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Daniel Veillard09ab7e12001-07-10 15:49:44 +0000[diff] [blame]1<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
2 "http://www.w3.org/TR/html4/loose.dtd">
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]3<html>
4<head>
Daniel Veillardec78c0f2000-08-25 10:25:23 +0000[diff] [blame]5 <title>The XML C library for Gnome</title>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]6 <meta name="GENERATOR" content="amaya 5.1">
Daniel Veillardb24054a1999-12-18 15:32:46 +0000[diff] [blame]7 <meta http-equiv="Content-Type" content="text/html">
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]8</head>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]9
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]10<body bgcolor="#ffffff">
Daniel Veillardec78c0f2000-08-25 10:25:23 +0000[diff] [blame]11<h1 align="center">The XML C library for Gnome</h1>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]12
Daniel Veillard9c466822001-10-25 12:03:39 +0000[diff] [blame]13<h1>Note: this is the flat content of the <a href="index.html">web
14site</a></h1>
15
Daniel Veillardc9484202001-10-24 12:35:52 +0000[diff] [blame]16<h1 style="text-align: center">libxml, a.k.a. gnome-xml</h1>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]17
18<p></p>
Daniel Veillard9c466822001-10-25 12:03:39 +0000[diff] [blame]19
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]20<p>Libxml is the XML C library developed for the Gnome project. XML itself
Daniel Veillard9c466822001-10-25 12:03:39 +0000[diff] [blame]21is a metalanguage to design markup languages, i.e. text language where
22semantic and structure are added to the content using extra "markup"
23information enclosed between angle bracket. HTML is the most well-known
Daniel Veillard1eb24242002-03-18 11:33:03 +0000[diff] [blame]24markup language. Though the library is written in C <a href="python.html">a
25variety of language binding</a> makes it available in other environments.</p>
Daniel Veillard9c466822001-10-25 12:03:39 +0000[diff] [blame]26
27<p>Libxml2 implements a number of existing standards related to markup
28languages:</p>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]29<ul>
Daniel Veillard9c466822001-10-25 12:03:39 +0000[diff] [blame]30 <li>the XML standard: <a
31 href="http://www.w3.org/TR/REC-xml">http://www.w3.org/TR/REC-xml</a></li>
32 <li>Namespaces in XML: <a
33 href="http://www.w3.org/TR/REC-xml-names/">http://www.w3.org/TR/REC-xml-names/</a></li>
34 <li>XML Base: <a
35 href="http://www.w3.org/TR/xmlbase/">http://www.w3.org/TR/xmlbase/</a></li>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]36 <li><a href="http://www.cis.ohio-state.edu/rfc/rfc2396.txt">RFC 2396</a> :
37 Uniform Resource Identifiers <a
Daniel Veillard9c466822001-10-25 12:03:39 +0000[diff] [blame]38 href="http://www.ietf.org/rfc/rfc2396.txt">http://www.ietf.org/rfc/rfc2396.txt</a></li>
39 <li>XML Path Language (XPath) 1.0: <a
40 href="http://www.w3.org/TR/xpath">http://www.w3.org/TR/xpath</a></li>
41 <li>HTML4 parser: <a
42 href="http://www.w3.org/TR/html401/">http://www.w3.org/TR/html401/</a></li>
43 <li>most of XML Pointer Language (XPointer) Version 1.0: <a
44 href="http://www.w3.org/TR/xptr">http://www.w3.org/TR/xptr</a></li>
45 <li>XML Inclusions (XInclude) Version 1.0: <a
46 href="http://www.w3.org/TR/xinclude/">http://www.w3.org/TR/xinclude/</a></li>
47 <li>[ISO-8859-1], <a
48 href="http://www.cis.ohio-state.edu/rfc/rfc2044.txt">rfc2044</a> [UTF-8]
49 and <a href="http://www.cis.ohio-state.edu/rfc/rfc2781.txt">rfc2781</a>
50 [UTF-16] core encodings</li>
51 <li>part of SGML Open Technical Resolution TR9401:1997</li>
52 <li>XML Catalogs Working Draft 06 August 2001: <a
53 href="http://www.oasis-open.org/committees/entity/spec-2001-08-06.html">http://www.oasis-open.org/committees/entity/spec-2001-08-06.html</a></li>
Daniel Veillard5c396542002-03-15 07:57:50 +0000[diff] [blame]54 <li>Canonical XML Version 1.0: <a
55 href="http://www.w3.org/TR/xml-c14n">http://www.w3.org/TR/xml-c14n</a>
Daniel Veillard2d347fa2002-03-17 10:34:11 +0000[diff] [blame]56 and the Exclusive XML Canonicalization CR draft <a
57 href="http://www.w3.org/TR/xml-exc-c14n">http://www.w3.org/TR/xml-exc-c14n</a></li>
Daniel Veillard96984452000-08-31 13:50:12 +0000[diff] [blame]58</ul>
59
Daniel Veillard9c466822001-10-25 12:03:39 +0000[diff] [blame]60<p>In most cases libxml tries to implement the specifications in a relatively
Daniel Veillarda5393562002-02-20 11:40:49 +0000[diff] [blame]61strict way. As of release 2.4.16, libxml2 passes all 1800+ tests from the <a
62href="http://www.oasis-open.org/committees/xml-conformance/">OASIS XML Tests
63Suite</a>.</p>
Daniel Veillard5b16f582002-02-20 11:38:46 +0000[diff] [blame]64
65<p>To some extent libxml2 provide some support for the following other
66specification but don't claim to implement them:</p>
Daniel Veillard9c466822001-10-25 12:03:39 +0000[diff] [blame]67<ul>
68 <li>Document Object Model (DOM) <a
69 href="http://www.w3.org/TR/DOM-Level-2-Core/">http://www.w3.org/TR/DOM-Level-2-Core/</a>
70 it doesn't implement the API itself, gdome2 does this in top of
71 libxml2</li>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]72 <li><a href="http://www.cis.ohio-state.edu/rfc/rfc959.txt">RFC 959</a> :
73 libxml implements a basic FTP client code</li>
74 <li><a href="http://www.cis.ohio-state.edu/rfc/rfc1945.txt">RFC 1945</a> :
75 HTTP/1.0, again a basic HTTP client code</li>
Daniel Veillard9c466822001-10-25 12:03:39 +0000[diff] [blame]76 <li>SAX: a minimal SAX implementation compatible with early expat
77 versions</li>
78 <li>DocBook SGML v4: libxml2 includes a hackish parser to transition to
79 XML</li>
80</ul>
81
Daniel Veillarde6d8e202002-05-02 06:11:10 +0000[diff] [blame]82<p>XML Schemas is being worked on but it would be far too early to make any
83conformance statement about it at the moment.</p>
84
Daniel Veillard2d347fa2002-03-17 10:34:11 +0000[diff] [blame]85<p>Libxml2 is known to be very portable, the library should build and work
86without serious troubles on a variety of systems (Linux, Unix, Windows,
87CygWin, MacOs, MacOsX, RISC Os, OS/2, VMS, QNX, MVS, ...)</p>
Daniel Veillard9c466822001-10-25 12:03:39 +0000[diff] [blame]88
Daniel Veillard96984452000-08-31 13:50:12 +0000[diff] [blame]89<p>Separate documents:</p>
90<ul>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]91 <li><a href="http://xmlsoft.org/XSLT/">the libxslt page</a> providing an
Daniel Veillard2d347fa2002-03-17 10:34:11 +0000[diff] [blame]92 implementation of XSLT 1.0 and common extensions like EXSLT for
93 libxml2</li>
Daniel Veillardc6271d22001-10-27 07:50:58 +0000[diff] [blame]94 <li><a href="http://www.cs.unibo.it/~casarini/gdome2/">the gdome2 page</a>
Daniel Veillard2d347fa2002-03-17 10:34:11 +0000[diff] [blame]95 : a standard DOM2 implementation for libxml2</li>
96 <li><a href="http://www.aleksey.com/xmlsec/">the XMLSec page</a>: an
97 implementation of <a href="http://www.w3.org/TR/xmldsig-core/">W3C XML
98 Digital Signature</a> for libxml2</li>
Daniel Veillarde6d8e202002-05-02 06:11:10 +0000[diff] [blame]99 <li>also check the related links section below for more related and active
100 projects.</li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]101</ul>
102
103<h2><a name="Introducti">Introduction</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]104
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]105<p>This document describes libxml, the <a
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]106href="http://www.w3.org/XML/">XML</a> C library developed for the <a
Daniel Veillardec78c0f2000-08-25 10:25:23 +0000[diff] [blame]107href="http://www.gnome.org/">Gnome</a> project. <a
108href="http://www.w3.org/XML/">XML is a standard</a> for building tag-based
109structured documents/data.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]110
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]111<p>Here are some key points about libxml:</p>
112<ul>
Daniel Veillard2d347fa2002-03-17 10:34:11 +0000[diff] [blame]113 <li>Libxml exports Push (progressive) and Pull (blocking) type parser
114 interfaces for both XML and HTML.</li>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]115 <li>Libxml can do DTD validation at parse time, using a parsed document
116 instance, or with an arbitrary DTD.</li>
Daniel Veillard2d347fa2002-03-17 10:34:11 +0000[diff] [blame]117 <li>Libxml includes complete <a
Daniel Veillard8c2ecaf2001-07-10 17:53:07 +0000[diff] [blame]118 href="http://www.w3.org/TR/xpath">XPath</a>, <a
119 href="http://www.w3.org/TR/xptr">XPointer</a> and <a
120 href="http://www.w3.org/TR/xinclude">XInclude</a> implementations.</li>
Daniel Veillardec78c0f2000-08-25 10:25:23 +0000[diff] [blame]121 <li>It is written in plain C, making as few assumptions as possible, and
Daniel Veillard189446d2000-10-13 10:23:06 +0000[diff] [blame]122 sticking closely to ANSI C/POSIX for easy embedding. Works on
Daniel Veillardab8500d2000-10-15 21:06:19 +0000[diff] [blame]123 Linux/Unix/Windows, ported to a number of other platforms.</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]124 <li>Basic support for HTTP and FTP client allowing applications to fetch
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]125 remote resources</li>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]126 <li>The design is modular, most of the extensions can be compiled out.</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]127 <li>The internal document representation is as close as possible to the <a
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]128 href="http://www.w3.org/DOM/">DOM</a> interfaces.</li>
129 <li>Libxml also has a <a href="http://www.megginson.com/SAX/index.html">SAX
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]130 like interface</a>; the interface is designed to be compatible with <a
131 href="http://www.jclark.com/xml/expat.html">Expat</a>.</li>
Daniel Veillardc575b992002-02-08 13:28:40 +0000[diff] [blame]132 <li>This library is released under the <a
133 href="http://www.opensource.org/licenses/mit-license.html">MIT
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]134 License</a> see the Copyright file in the distribution for the precise
Daniel Veillardc575b992002-02-08 13:28:40 +0000[diff] [blame]135 wording.</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]136</ul>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]137
Daniel Veillarde0c1d722001-03-21 10:28:36 +0000[diff] [blame]138<p>Warning: unless you are forced to because your application links with a
Daniel Veillard2d347fa2002-03-17 10:34:11 +0000[diff] [blame]139Gnome-1.X library requiring it, <strong><span
Daniel Veillarde0c1d722001-03-21 10:28:36 +0000[diff] [blame]140style="background-color: #FF0000">Do Not Use libxml1</span></strong>, use
141libxml2</p>
142
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]143<h2><a name="FAQ">FAQ</a></h2>
144
145<p>Table of Content:</p>
146<ul>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]147 <li><a href="FAQ.html#License">License(s)</a></li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]148 <li><a href="FAQ.html#Installati">Installation</a></li>
149 <li><a href="FAQ.html#Compilatio">Compilation</a></li>
150 <li><a href="FAQ.html#Developer">Developer corner</a></li>
151</ul>
152
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]153<h3><a name="License">License</a>(s)</h3>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]154<ol>
155 <li><em>Licensing Terms for libxml</em>
Daniel Veillardc575b992002-02-08 13:28:40 +0000[diff] [blame]156 <p>libxml is released under the <a
157 href="http://www.opensource.org/licenses/mit-license.html">MIT
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]158 License</a>, see the file Copyright in the distribution for the precise
Daniel Veillardc575b992002-02-08 13:28:40 +0000[diff] [blame]159 wording</p>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]160 </li>
161 <li><em>Can I embed libxml in a proprietary application ?</em>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]162 <p>Yes. The MIT License allows you to also keep proprietary the changes
Daniel Veillardc0801af2002-05-28 16:28:42 +0000[diff] [blame]163 you made to libxml, but it would be graceful to provide back bug fixes
164 and improvements as patches for possible incorporation in the main
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]165 development tree</p>
166 </li>
167</ol>
168
169<h3><a name="Installati">Installation</a></h3>
170<ol>
171 <li>Unless you are forced to because your application links with a Gnome
172 library requiring it, <strong><span style="background-color: #FF0000">Do
173 Not Use libxml1</span></strong>, use libxml2</li>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]174 <li><em>Where can I get libxml</em> ?
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]175 <p>The original distribution comes from <a
176 href="ftp://rpmfind.net/pub/libxml/">rpmfind.net</a> or <a
177 href="ftp://ftp.gnome.org/pub/GNOME/stable/sources/libxml/">gnome.org</a></p>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]178 <p>Most Linux and BSD distributions include libxml, this is probably the
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]179 safer way for end-users</p>
180 <p>David Doolin provides precompiled Windows versions at <a
181 href="http://www.ce.berkeley.edu/~doolin/code/libxmlwin32/ ">http://www.ce.berkeley.edu/~doolin/code/libxmlwin32/</a></p>
182 </li>
183 <li><em>I see libxml and libxml2 releases, which one should I install ?</em>
184 <ul>
185 <li>If you are not concerned by any existing backward compatibility
186 with existing application, install libxml2 only</li>
187 <li>If you are not doing development, you can safely install both.
188 usually the packages <a
189 href="http://rpmfind.net/linux/RPM/libxml.html">libxml</a> and <a
190 href="http://rpmfind.net/linux/RPM/libxml2.html">libxml2</a> are
191 compatible (this is not the case for development packages)</li>
192 <li>If you are a developer and your system provides separate packaging
193 for shared libraries and the development components, it is possible
194 to install libxml and libxml2, and also <a
195 href="http://rpmfind.net/linux/RPM/libxml-devel.html">libxml-devel</a>
196 and <a
197 href="http://rpmfind.net/linux/RPM/libxml2-devel.html">libxml2-devel</a>
198 too for libxml2 &gt;= 2.3.0</li>
199 <li>If you are developing a new application, please develop against
200 libxml2(-devel)</li>
201 </ul>
202 </li>
203 <li><em>I can't install the libxml package it conflicts with libxml0</em>
204 <p>You probably have an old libxml0 package used to provide the shared
205 library for libxml.so.0, you can probably safely remove it. Anyway the
206 libxml packages provided on <a
207 href="ftp://rpmfind.net/pub/libxml/">rpmfind.net</a> provides
208 libxml.so.0</p>
209 </li>
210 <li><em>I can't install the libxml(2) RPM package due to failed
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]211 dependencies</em>
212 <p>The most generic solution is to re-fetch the latest src.rpm , and
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]213 rebuild it locally with</p>
214 <p><code>rpm --rebuild libxml(2)-xxx.src.rpm</code></p>
215 <p>if everything goes well it will generate two binary rpm (one providing
216 the shared libs and xmllint, and the other one, the -devel package
217 providing includes, static libraries and scripts needed to build
218 applications with libxml(2)) that you can install locally.</p>
219 </li>
220</ol>
221
222<h3><a name="Compilatio">Compilation</a></h3>
223<ol>
224 <li><em>What is the process to compile libxml ?</em>
225 <p>As most UNIX libraries libxml follows the "standard":</p>
226 <p><code>gunzip -c xxx.tar.gz | tar xvf -</code></p>
227 <p><code>cd libxml-xxxx</code></p>
228 <p><code>./configure --help</code></p>
229 <p>to see the options, then the compilation/installation proper</p>
230 <p><code>./configure [possible options]</code></p>
231 <p><code>make</code></p>
232 <p><code>make install</code></p>
233 <p>At that point you may have to rerun ldconfig or similar utility to
234 update your list of installed shared libs.</p>
235 </li>
236 <li><em>What other libraries are needed to compile/install libxml ?</em>
237 <p>Libxml does not requires any other library, the normal C ANSI API
238 should be sufficient (please report any violation to this rule you may
239 find).</p>
240 <p>However if found at configuration time libxml will detect and use the
241 following libs:</p>
242 <ul>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]243 <li><a href="http://www.info-zip.org/pub/infozip/zlib/">libz</a> : a
244 highly portable and available widely compression library</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]245 <li>iconv: a powerful character encoding conversion library. It's
246 included by default on recent glibc libraries, so it doesn't need to
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]247 be installed specifically on Linux. It seems it's now <a
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]248 href="http://www.opennc.org/onlinepubs/7908799/xsh/iconv.html">part
249 of the official UNIX</a> specification. Here is one <a
250 href="http://clisp.cons.org/~haible/packages-libiconv.html">implementation
251 of the library</a> which source can be found <a
252 href="ftp://ftp.ilog.fr/pub/Users/haible/gnu/">here</a>.</li>
253 </ul>
254 </li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]255 <li><em>make check fails on some platforms</em>
256 <p>Sometime the regression tests results don't completely match the value
257 produced by the parser, and the makefile uses diff to print the delta. On
258 some platforms the diff return breaks the compilation process, if the
Daniel Veillarde46182c2002-02-12 14:29:11 +0000[diff] [blame]259 diff is small this is probably not a serious problem.</p>
260 <p>Sometimes (especially on Solaris) make checks fails due to limitations
261 in make. Try using GNU-make instead.</p>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]262 </li>
263 <li><em>I use the CVS version and there is no configure script</em>
264 <p>The configure (and other Makefiles) are generated. Use the autogen.sh
265 script to regenerate the configure and Makefiles, like:</p>
266 <p><code>./autogen.sh --prefix=/usr --disable-shared</code></p>
267 </li>
268 <li><em>I have troubles when running make tests with gcc-3.0</em>
269 <p>It seems the initial release of gcc-3.0 has a problem with the
270 optimizer which miscompiles the URI module. Please use another
271 compiler</p>
272 </li>
273</ol>
274
275<h3><a name="Developer">Developer</a> corner</h3>
276<ol>
277 <li><em>xmlDocDump() generates output on one line</em>
278 <p>libxml will not <strong>invent</strong> spaces in the content of a
279 document since <strong>all spaces in the content of a document are
280 significant</strong>. If you build a tree from the API and want
281 indentation:</p>
282 <ol>
283 <li>the correct way is to generate those yourself too</li>
284 <li>the dangerous way is to ask libxml to add those blanks to your
285 content <strong>modifying the content of your document in the
286 process</strong>. The result may not be what you expect. There is
287 <strong>NO</strong> way to guarantee that such a modification won't
288 impact other part of the content of your document. See <a
289 href="http://xmlsoft.org/html/libxml-parser.html#XMLKEEPBLANKSDEFAULT">xmlKeepBlanksDefault
290 ()</a> and <a
291 href="http://xmlsoft.org/html/libxml-tree.html#XMLSAVEFORMATFILE">xmlSaveFormatFile
292 ()</a></li>
293 </ol>
294 </li>
295 <li>Extra nodes in the document:
296 <p><em>For a XML file as below:</em></p>
297 <pre>&lt;?xml version="1.0"?&gt;
298&lt;PLAN xmlns="http://www.argus.ca/autotest/1.0/"&gt;
299&lt;NODE CommFlag="0"/&gt;
300&lt;NODE CommFlag="1"/&gt;
301&lt;/PLAN&gt;</pre>
302 <p><em>after parsing it with the function
303 pxmlDoc=xmlParseFile(...);</em></p>
304 <p><em>I want to the get the content of the first node (node with the
305 CommFlag="0")</em></p>
306 <p><em>so I did it as following;</em></p>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]307 <pre>xmlNodePtr pnode;
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]308pnode=pxmlDoc-&gt;children-&gt;children;</pre>
309 <p><em>but it does not work. If I change it to</em></p>
310 <pre>pnode=pxmlDoc-&gt;children-&gt;children-&gt;next;</pre>
311 <p><em>then it works. Can someone explain it to me.</em></p>
312 <p></p>
313 <p>In XML all characters in the content of the document are significant
314 <strong>including blanks and formatting line breaks</strong>.</p>
315 <p>The extra nodes you are wondering about are just that, text nodes with
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]316 the formatting spaces which are part of the document but that people tend
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]317 to forget. There is a function <a
318 href="http://xmlsoft.org/html/libxml-parser.html">xmlKeepBlanksDefault
319 ()</a> to remove those at parse time, but that's an heuristic, and its
320 use should be limited to case where you are sure there is no
321 mixed-content in the document.</p>
322 </li>
323 <li><em>I get compilation errors of existing code like when accessing
324 <strong>root</strong> or <strong>childs fields</strong> of nodes</em>
325 <p>You are compiling code developed for libxml version 1 and using a
326 libxml2 development environment. Either switch back to libxml v1 devel or
327 even better fix the code to compile with libxml2 (or both) by <a
328 href="upgrade.html">following the instructions</a>.</p>
329 </li>
330 <li><em>I get compilation errors about non existing
331 <strong>xmlRootNode</strong> or <strong>xmlChildrenNode</strong>
332 fields</em>
333 <p>The source code you are using has been <a
334 href="upgrade.html">upgraded</a> to be able to compile with both libxml
335 and libxml2, but you need to install a more recent version:
336 libxml(-devel) &gt;= 1.8.8 or libxml2(-devel) &gt;= 2.1.0</p>
337 </li>
338 <li><em>XPath implementation looks seriously broken</em>
339 <p>XPath implementation prior to 2.3.0 was really incomplete, upgrade to
Daniel Veillard2d347fa2002-03-17 10:34:11 +0000[diff] [blame]340 a recent version, there is no known bug in the current version.</p>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]341 </li>
342 <li><em>The example provided in the web page does not compile</em>
343 <p>It's hard to maintain the documentation in sync with the code
344 &lt;grin/&gt; ...</p>
345 <p>Check the previous points 1/ and 2/ raised before, and send
346 patches.</p>
347 </li>
348 <li><em>Where can I get more examples and informations than in the web
349 page</em>
350 <p>Ideally a libxml book would be nice. I have no such plan ... But you
351 can:</p>
352 <ul>
353 <li>check more deeply the <a href="html/libxml-lib.html">existing
354 generated doc</a></li>
355 <li>looks for examples of use for libxml function using the Gnome code
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]356 for example the following will query the full Gnome CVS base for the
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]357 use of the <strong>xmlAddChild()</strong> function:
358 <p><a
359 href="http://cvs.gnome.org/lxr/search?string=xmlAddChild">http://cvs.gnome.org/lxr/search?string=xmlAddChild</a></p>
360 <p>This may be slow, a large hardware donation to the gnome project
361 could cure this :-)</p>
362 </li>
363 <li><a
364 href="http://cvs.gnome.org/bonsai/rview.cgi?cvsroot=/cvs/gnome&amp;dir=gnome-xml">Browse
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]365 the libxml source</a> , I try to write code as clean and documented
Daniel Veillard2d347fa2002-03-17 10:34:11 +0000[diff] [blame]366 as possible, so looking at it may be helpful. Especially the code of
367 xmllint.c and of the various testXXX.c tests programs should provide
368 good example on how to do things with the library.</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]369 </ul>
370 </li>
371 <li>What about C++ ?
372 <p>libxml is written in pure C in order to allow easy reuse on a number
373 of platforms, including embedded systems. I don't intend to convert to
374 C++.</p>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]375 <p>There is however a few C++ wrappers which may fulfill your needs:</p>
Daniel Veillard9b6fd302002-05-13 12:06:47 +0000[diff] [blame]376 <ul>
377 <li>by Ari Johnson &lt;ari@btigate.com&gt;:
378 <p>Website: <a
379 href="http://lusis.org/~ari/xml++/">http://lusis.org/~ari/xml++/</a></p>
380 <p>Download: <a
381 href="http://lusis.org/~ari/xml++/libxml++.tar.gz">http://lusis.org/~ari/xml++/libxml++.tar.gz</a></p>
382 </li>
383 <li>by Peter Jones &lt;pjones@pmade.org&gt;
384 <p>Website: <a
385 href="http://pmade.org/pjones/software/xmlwrapp/">http://pmade.org/pjones/software/xmlwrapp/</a></p>
386 </li>
387 </ul>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]388 </li>
389 <li>How to validate a document a posteriori ?
390 <p>It is possible to validate documents which had not been validated at
391 initial parsing time or documents who have been built from scratch using
392 the API. Use the <a
393 href="http://xmlsoft.org/html/libxml-valid.html#XMLVALIDATEDTD">xmlValidateDtd()</a>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]394 function. It is also possible to simply add a DTD to an existing
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]395 document:</p>
396 <pre>xmlDocPtr doc; /* your existing document */
397 xmlDtdPtr dtd = xmlParseDTD(NULL, filename_of_dtd); /* parse the DTD */
398 dtd-&gt;name = xmlStrDup((xmlChar*)"root_name"); /* use the given root */
399
400 doc-&gt;intSubset = dtd;
401 if (doc-&gt;children == NULL) xmlAddChild((xmlNodePtr)doc, (xmlNodePtr)dtd);
402 else xmlAddPrevSibling(doc-&gt;children, (xmlNodePtr)dtd);
403 </pre>
404 </li>
405 <li>etc ...</li>
406</ol>
407
408<p></p>
409
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]410<h2><a name="Documentat">Documentation</a></h2>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]411
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]412<p>There are some on-line resources about using libxml:</p>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]413<ol>
Daniel Veillard365e13b2000-07-02 07:56:37 +0000[diff] [blame]414 <li>Check the <a href="FAQ.html">FAQ</a></li>
Daniel Veillardc19fccc2000-07-03 11:52:01 +0000[diff] [blame]415 <li>Check the <a href="http://xmlsoft.org/html/libxml-lib.html">extensive
Daniel Veillard8c6d6af2000-08-25 17:14:13 +0000[diff] [blame]416 documentation</a> automatically extracted from code comments (using <a
417 href="http://cvs.gnome.org/bonsai/rview.cgi?cvsroot=/cvs/gnome&amp;dir=gtk-doc">gtk
418 doc</a>).</li>
Daniel Veillard8d869642000-07-14 12:12:59 +0000[diff] [blame]419 <li>Look at the documentation about <a href="encoding.html">libxml
420 internationalization support</a></li>
Daniel Veillardbc66f852002-01-14 09:49:20 +0000[diff] [blame]421 <li>This page provides a global overview and <a href="example.html">some
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]422 examples</a> on how to use libxml.</li>
MDT 2002 John Fleckd7ca7f92002-06-13 03:41:03 +0000[diff] [blame]423 <li>John Fleck's <a href="tutorial/index.html">libxml tutorial</a></li>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]424 <li><a href="mailto:james@daa.com.au">James Henstridge</a> wrote <a
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]425 href="http://www.daa.com.au/~james/gnome/xml-sax/xml-sax.html">some nice
426 documentation</a> explaining how to use the libxml SAX interface.</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]427 <li>George Lebl wrote <a
428 href="http://www-4.ibm.com/software/developer/library/gnome3/">an article
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]429 for IBM developerWorks</a> about using libxml.</li>
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]430 <li>Check <a href="http://cvs.gnome.org/lxr/source/gnome-xml/TODO">the TODO
431 file</a></li>
432 <li>Read the <a href="upgrade.html">1.x to 2.x upgrade path</a>. If you are
433 starting a new project using libxml you should really use the 2.x
434 version.</li>
Daniel Veillard845cce42002-01-09 11:51:37 +0000[diff] [blame]435 <li>And don't forget to look at the <a
436 href="http://mail.gnome.org/archives/xml/">mailing-list archive</a>.</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]437</ol>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]438
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]439<h2><a name="Reporting">Reporting bugs and getting help</a></h2>
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000[diff] [blame]440
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]441<p>Well, bugs or missing features are always possible, and I will make a
442point of fixing them in a timely fashion. The best way to report a bug is to
443use the <a href="http://bugzilla.gnome.org/buglist.cgi?product=libxml">Gnome
444bug tracking database</a> (make sure to use the "libxml" module name). I look
445at reports there regularly and it's good to have a reminder when a bug is
Daniel Veillard51095312001-10-28 18:51:57 +0000[diff] [blame]446still open. Be sure to specify that the bug is for the package libxml.</p>
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000[diff] [blame]447
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]448<p>There is also a mailing-list <a
Daniel Veillard3197f162001-04-04 00:40:08 +0000[diff] [blame]449href="mailto:xml@gnome.org">xml@gnome.org</a> for libxml, with an <a
450href="http://mail.gnome.org/archives/xml/">on-line archive</a> (<a
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]451href="http://xmlsoft.org/messages">old</a>). To subscribe to this list,
452please visit the <a
453href="http://mail.gnome.org/mailman/listinfo/xml">associated Web</a> page and
454follow the instructions. <strong>Do not send code, I won't debug it</strong>
455(but patches are really appreciated!).</p>
Daniel Veillard234547b2001-07-05 09:46:10 +0000[diff] [blame]456
Daniel Veillard008186f2001-09-13 14:24:44 +0000[diff] [blame]457<p>Check the following <strong><span style="color: #FF0000">before
458posting</span></strong>:</p>
Daniel Veillard234547b2001-07-05 09:46:10 +0000[diff] [blame]459<ul>
Daniel Veillarddadd0872001-09-15 09:21:44 +0000[diff] [blame]460 <li>read the <a href="FAQ.html">FAQ</a></li>
Daniel Veillard234547b2001-07-05 09:46:10 +0000[diff] [blame]461 <li>make sure you are <a href="ftp://xmlsoft.org/">using a recent
462 version</a>, and that the problem still shows up in those</li>
463 <li>check the <a href="http://mail.gnome.org/archives/xml/">list
464 archives</a> to see if the problem was reported already, in this case
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]465 there is probably a fix available, similarly check the <a
Daniel Veillarde7ead2d2001-08-22 23:44:09 +0000[diff] [blame]466 href="http://bugzilla.gnome.org/buglist.cgi?product=libxml">registered
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]467 open bugs</a></li>
Daniel Veillard234547b2001-07-05 09:46:10 +0000[diff] [blame]468 <li>make sure you can reproduce the bug with xmllint or one of the test
469 programs found in source in the distribution</li>
470 <li>Please send the command showing the error as well as the input (as an
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]471 attachment)</li>
Daniel Veillard234547b2001-07-05 09:46:10 +0000[diff] [blame]472</ul>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]473
Daniel Veillarddadd0872001-09-15 09:21:44 +0000[diff] [blame]474<p>Then send the bug with associated informations to reproduce it to the <a
Daniel Veillard33a67802001-03-07 09:44:02 +0000[diff] [blame]475href="mailto:xml@gnome.org">xml@gnome.org</a> list; if it's really libxml
Daniel Veillard008186f2001-09-13 14:24:44 +0000[diff] [blame]476related I will approve it.. Please do not send me mail directly, it makes
477things really harder to track and in some cases I'm not the best person to
478answer a given question, ask the list instead.</p>
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000[diff] [blame]479
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]480<p>Of course, bugs reported with a suggested patch for fixing them will
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]481probably be processed faster.</p>
482
483<p>If you're looking for help, a quick look at <a
Daniel Veillardf7ed3362001-08-17 12:01:21 +0000[diff] [blame]484href="http://mail.gnome.org/archives/xml/">the list archive</a> may actually
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]485provide the answer, I usually send source samples when answering libxml usage
Daniel Veillard6f0adb52000-07-03 11:41:26 +0000[diff] [blame]486questions. The <a href="http://xmlsoft.org/html/book1.html">auto-generated
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]487documentation</a> is not as polished as I would like (i need to learn more
488about DocBook), but it's a good starting point.</p>
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]489
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]490<h2><a name="help">How to help</a></h2>
491
492<p>You can help the project in various ways, the best thing to do first is to
493subscribe to the mailing-list as explained before, check the <a
Daniel Veillardf7ed3362001-08-17 12:01:21 +0000[diff] [blame]494href="http://mail.gnome.org/archives/xml/">archives </a>and the <a
495href="http://bugzilla.gnome.org/buglist.cgi?product=libxml">Gnome bug
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]496database:</a>:</p>
497<ol>
498 <li>provide patches when you find problems</li>
Daniel Veillard189446d2000-10-13 10:23:06 +0000[diff] [blame]499 <li>provide the diffs when you port libxml to a new platform. They may not
Daniel Veillardab8500d2000-10-15 21:06:19 +0000[diff] [blame]500 be integrated in all cases but help pinpointing portability problems
501 and</li>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]502 <li>provide documentation fixes (either as patches to the code comments or
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]503 as HTML diffs).</li>
504 <li>provide new documentations pieces (translations, examples, etc ...)</li>
505 <li>Check the TODO file and try to close one of the items</li>
506 <li>take one of the points raised in the archive or the bug database and
Daniel Veillarde7ead2d2001-08-22 23:44:09 +0000[diff] [blame]507 provide a fix. <a href="mailto:daniel@veillard.com">Get in touch with me
508 </a>before to avoid synchronization problems and check that the suggested
509 fix will fit in nicely :-)</li>
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]510</ol>
511
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]512<h2><a name="Downloads">Downloads</a></h2>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]513
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]514<p>The latest versions of libxml can be found on <a
Daniel Veillard20c8cf22001-06-26 22:47:36 +0000[diff] [blame]515href="ftp://xmlsoft.org/">xmlsoft.org</a> (<a
516href="ftp://speakeasy.rpmfind.net/pub/libxml/">Seattle</a>, <a
517href="ftp://fr.rpmfind.net/pub/libxml/">France</a>) or on the <a
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]518href="ftp://ftp.gnome.org/pub/GNOME/MIRRORS.html">Gnome FTP server</a> either
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]519as a <a href="ftp://ftp.gnome.org/pub/GNOME/stable/sources/libxml/">source
Daniel Veillard306be992000-07-03 12:38:45 +0000[diff] [blame]520archive</a> or <a
Daniel Veillarda41123c2001-04-22 19:31:20 +0000[diff] [blame]521href="ftp://ftp.gnome.org/pub/GNOME/stable/redhat/i386/libxml/">RPM
Daniel Veillard0bfbb422002-04-26 09:21:45 +0000[diff] [blame]522packages</a>, Antonin Sprinzl also provide <a
523href="ftp://gd.tuwien.ac.at/pub/libxml/">a mirror in Austria</a>. (NOTE that
524you need both the <a
Daniel Veillardc19fccc2000-07-03 11:52:01 +0000[diff] [blame]525href="http://rpmfind.net/linux/RPM/libxml2.html">libxml(2)</a> and <a
526href="http://rpmfind.net/linux/RPM/libxml2-devel.html">libxml(2)-devel</a>
Daniel Veillard95189532001-07-26 18:30:26 +0000[diff] [blame]527packages installed to compile applications using libxml.) <a
Daniel Veillardb2fb8ed2002-04-01 09:33:12 +0000[diff] [blame]528href="mailto:igor@stud.fh-frankfurt.de">Igor Zlatkovic</a> is now the
529maintainer of the Windows port, <a
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]530href="http://www.fh-frankfurt.de/~igor/projects/libxml/index.html">he
Daniel Veillardc6271d22001-10-27 07:50:58 +0000[diff] [blame]531provides binaries</a>. <a href="mailto:Gary.Pennington@sun.com">Gary
Daniel Veillard1aadc442001-11-28 13:10:32 +0000[diff] [blame]532Pennington</a> provides <a href="http://garypennington.net/libxml2/">Solaris
533binaries</a>.</p>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]534
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]535<p><a name="Snapshot">Snapshot:</a></p>
536<ul>
537 <li>Code from the W3C cvs base libxml <a
Daniel Veillard33a67802001-03-07 09:44:02 +0000[diff] [blame]538 href="ftp://xmlsoft.org/cvs-snapshot.tar.gz">cvs-snapshot.tar.gz</a></li>
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]539 <li>Docs, content of the web site, the list archive included <a
Daniel Veillard33a67802001-03-07 09:44:02 +0000[diff] [blame]540 href="ftp://xmlsoft.org/libxml-docs.tar.gz">libxml-docs.tar.gz</a></li>
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]541</ul>
542
Daniel Veillardc6271d22001-10-27 07:50:58 +0000[diff] [blame]543<p><a name="Contribs">Contributions:</a></p>
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]544
545<p>I do accept external contributions, especially if compiling on another
Daniel Veillardc6271d22001-10-27 07:50:58 +0000[diff] [blame]546platform, get in touch with me to upload the package, wrappers for various
Daniel Veillard51095312001-10-28 18:51:57 +0000[diff] [blame]547languages have been provided, and can be found in the <a
548href="contribs.html">contrib section</a></p>
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]549
Daniel Veillard82687162001-01-22 15:32:01 +0000[diff] [blame]550<p>Libxml is also available from CVS:</p>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]551<ul>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]552 <li><p>The <a
553 href="http://cvs.gnome.org/bonsai/rview.cgi?cvsroot=/cvs/gnome&amp;dir=gnome-xml">Gnome
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]554 CVS base</a>. Check the <a
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]555 href="http://developer.gnome.org/tools/cvs.html">Gnome CVS Tools</a>
556 page; the CVS module is <b>gnome-xml</b>.</p>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]557 </li>
Daniel Veillard82687162001-01-22 15:32:01 +0000[diff] [blame]558 <li>The <strong>libxslt</strong> module is also present there</li>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]559</ul>
560
561<h2><a name="News">News</a></h2>
562
Daniel Veillard944b5ff1999-12-15 19:08:24 +0000[diff] [blame]563<h3>CVS only : check the <a
564href="http://cvs.gnome.org/lxr/source/gnome-xml/ChangeLog">Changelog</a> file
Daniel Veillard189446d2000-10-13 10:23:06 +0000[diff] [blame]565for a really accurate description</h3>
Daniel Veillardab8500d2000-10-15 21:06:19 +0000[diff] [blame]566
Daniel Veillarde6d8e202002-05-02 06:11:10 +0000[diff] [blame]567<p>Items not finished and worked on, get in touch with the list if you want
568to test those</p>
Daniel Veillardab8500d2000-10-15 21:06:19 +0000[diff] [blame]569<ul>
Daniel Veillardcf27f7c2002-04-30 07:12:39 +0000[diff] [blame]570 <li>Finishing up <a href="http://www.w3.org/TR/xmlschema-1/">XML
571 Schemas</a> and <a href="http://www.w3.org/TR/xinclude">XInclude</a></li>
572</ul>
573
Daniel Veillardc0801af2002-05-28 16:28:42 +0000[diff] [blame]574<h3>2.4.22: May 27 2002</h3>
575<ul>
576 <li>a number of bug fixes: configure scripts, base handling, parser, memory
577 usage, HTML parser, XPath, documentation (Christian Cornelssen),
Daniel Veillard21473672002-06-17 07:29:22 +0000[diff] [blame]578 indentation, URI parsing</li>
Daniel Veillardc0801af2002-05-28 16:28:42 +0000[diff] [blame]579 <li>Optimizations for XMLSec, fixing and making public some of the network
580 protocol handlers (Aleksey)</li>
581 <li>performance patch from Gary Pennington</li>
582 <li>Charles Bozeman provided date and time support for XML Schemas
583 datatypes</li>
584</ul>
585
Daniel Veillardcf27f7c2002-04-30 07:12:39 +0000[diff] [blame]586<h3>2.4.21: Apr 29 2002</h3>
587
588<p>This release is both a bug fix release and also contains the early XML
589Schemas <a href="http://www.w3.org/TR/xmlschema-1/">structures</a> and <a
590href="http://www.w3.org/TR/xmlschema-2/">datatypes</a> code, beware, all
591interfaces are likely to change, there is huge holes, it is clearly a work in
592progress and don't even think of putting this code in a production system,
Daniel Veillarde6d8e202002-05-02 06:11:10 +0000[diff] [blame]593it's actually not compiled in by default. The real fixes are:</p>
Daniel Veillardcf27f7c2002-04-30 07:12:39 +0000[diff] [blame]594<ul>
595 <li>a couple of bugs or limitations introduced in 2.4.20</li>
596 <li>patches for Borland C++ and MSC by Igor</li>
597 <li>some fixes on XPath strings and conformance patches by Richard
598 Jinks</li>
599 <li>patch from Aleksey for the ExcC14N specification</li>
600 <li>OSF/1 bug fix by Bjorn</li>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]601</ul>
602
Daniel Veillarda7084cd2002-04-15 17:12:47 +0000[diff] [blame]603<h3>2.4.20: Apr 15 2002</h3>
604<ul>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]605 <li>bug fixes: file descriptor leak, XPath, HTML output, DTD validation</li>
Daniel Veillarda7084cd2002-04-15 17:12:47 +0000[diff] [blame]606 <li>XPath conformance testing by Richard Jinks</li>
607 <li>Portability fixes: Solaris, MPE/iX, Windows, OSF/1, python bindings,
608 libxml.m4</li>
609</ul>
610
Daniel Veillard19274092002-03-25 16:48:03 +0000[diff] [blame]611<h3>2.4.19: Mar 25 2002</h3>
612<ul>
613 <li>bug fixes: half a dozen XPath bugs, Validation, ISO-Latin to UTF8
614 encoder</li>
615 <li>portability fixes in the HTTP code</li>
Daniel Veillardb2fb8ed2002-04-01 09:33:12 +0000[diff] [blame]616 <li>memory allocation checks using valgrind, and profiling tests</li>
Daniel Veillard19274092002-03-25 16:48:03 +0000[diff] [blame]617 <li>revamp of the Windows build and Makefiles</li>
618</ul>
619
Daniel Veillard34ce8be2002-03-18 19:37:11 +0000[diff] [blame]620<h3>2.4.18: Mar 18 2002</h3>
621<ul>
622 <li>bug fixes: tree, SAX, canonicalization, validation, portability,
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]623 XPath</li>
Daniel Veillard34ce8be2002-03-18 19:37:11 +0000[diff] [blame]624 <li>removed the --with-buffer option it was becoming unmaintainable</li>
625 <li>serious cleanup of the Python makefiles</li>
626 <li>speedup patch to XPath very effective for DocBook stylesheets</li>
627 <li>Fixes for Windows build, cleanup of the documentation</li>
628</ul>
629
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]630<h3>2.4.17: Mar 8 2002</h3>
631<ul>
632 <li>a lot of bug fixes, including "namespace nodes have no parents in
633 XPath"</li>
634 <li>fixed/improved the Python wrappers, added more examples and more
635 regression tests, XPath extension functions can now return node-sets</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]636 <li>added the XML Canonicalization support from Aleksey Sanin</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]637</ul>
638
Daniel Veillard5f4b5992002-02-20 10:22:49 +0000[diff] [blame]639<h3>2.4.16: Feb 20 2002</h3>
640<ul>
641 <li>a lot of bug fixes, most of them were triggered by the XML Testsuite
642 from OASIS and W3C. Compliance has been significantly improved.</li>
643 <li>a couple of portability fixes too.</li>
644</ul>
645
Daniel Veillard397ff112002-02-11 18:27:20 +0000[diff] [blame]646<h3>2.4.15: Feb 11 2002</h3>
647<ul>
648 <li>Fixed the Makefiles, especially the python module ones</li>
649 <li>A few bug fixes and cleanup</li>
650 <li>Includes cleanup</li>
651</ul>
652
Daniel Veillardb6c1e2f2002-02-08 14:52:52 +0000[diff] [blame]653<h3>2.4.14: Feb 8 2002</h3>
654<ul>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]655 <li>Change of License to the <a
Daniel Veillardb6c1e2f2002-02-08 14:52:52 +0000[diff] [blame]656 href="http://www.opensource.org/licenses/mit-license.html">MIT
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]657 License</a> basically for integration in XFree86 codebase, and removing
658 confusion around the previous dual-licensing</li>
Daniel Veillardb6c1e2f2002-02-08 14:52:52 +0000[diff] [blame]659 <li>added Python bindings, beta software but should already be quite
660 complete</li>
661 <li>a large number of fixes and cleanups, especially for all tree
662 manipulations</li>
663 <li>cleanup of the headers, generation of a reference API definition in
664 XML</li>
665</ul>
666
667<h3>2.4.13: Jan 14 2002</h3>
Daniel Veillard744683d2002-01-14 17:30:20 +0000[diff] [blame]668<ul>
669 <li>update of the documentation: John Fleck and Charlie Bozeman</li>
670 <li>cleanup of timing code from Justin Fletcher</li>
671 <li>fixes for Windows and initial thread support on Win32: Igor and Serguei
672 Narojnyi</li>
673 <li>Cygwin patch from Robert Collins</li>
674 <li>added xmlSetEntityReferenceFunc() for Keith Isdale work on xsldbg</li>
675</ul>
676
Daniel Veillardef90ba72001-12-07 14:24:22 +0000[diff] [blame]677<h3>2.4.12: Dec 7 2001</h3>
678<ul>
679 <li>a few bug fixes: thread (Gary Pennington), xmllint (Geert Kloosterman),
680 XML parser (Robin Berjon), XPointer (Danny Jamshy), I/O cleanups
681 (robert)</li>
682 <li>Eric Lavigne contributed project files for MacOS</li>
683 <li>some makefiles cleanups</li>
684</ul>
685
Daniel Veillarda4871052001-11-26 13:19:48 +0000[diff] [blame]686<h3>2.4.11: Nov 26 2001</h3>
687<ul>
688 <li>fixed a couple of errors in the includes, fixed a few bugs, some code
689 cleanups</li>
690 <li>xmllint man pages improvement by Heiko Rupp</li>
691 <li>updated VMS build instructions from John A Fotheringham</li>
692 <li>Windows Makefiles updates from Igor</li>
693</ul>
694
Daniel Veillard43d3f612001-11-10 11:57:23 +0000[diff] [blame]695<h3>2.4.10: Nov 10 2001</h3>
696<ul>
697 <li>URI escaping fix (Joel Young)</li>
698 <li>added xmlGetNodePath() (for paths or XPointers generation)</li>
699 <li>Fixes namespace handling problems when using DTD and validation</li>
700 <li>improvements on xmllint: Morus Walter patches for --format and
701 --encode, Stefan Kost and Heiko Rupp improvements on the --shell</li>
702 <li>fixes for xmlcatalog linking pointed by Weiqi Gao</li>
703 <li>fixes to the HTML parser</li>
704</ul>
705
706<h3>2.4.9: Nov 6 2001</h3>
707<ul>
708 <li>fixes more catalog bugs</li>
709 <li>avoid a compilation problem, improve xmlGetLineNo()</li>
710</ul>
711
Daniel Veillarded421aa2001-11-04 21:22:45 +0000[diff] [blame]712<h3>2.4.8: Nov 4 2001</h3>
713<ul>
714 <li>fixed SGML catalogs broken in previous release, updated xmlcatalog
715 tool</li>
716 <li>fixed a compile errors and some includes troubles.</li>
717</ul>
718
Daniel Veillard52dcab32001-10-30 12:51:17 +0000[diff] [blame]719<h3>2.4.7: Oct 30 2001</h3>
720<ul>
721 <li>exported some debugging interfaces</li>
722 <li>serious rewrite of the catalog code</li>
723 <li>integrated Gary Pennington thread safety patch, added configure option
724 and regression tests</li>
725 <li>removed an HTML parser bug</li>
726 <li>fixed a couple of potentially serious validation bugs</li>
727 <li>integrated the SGML DocBook support in xmllint</li>
728 <li>changed the nanoftp anonymous login passwd</li>
729 <li>some I/O cleanup and a couple of interfaces for Perl wrapper</li>
730 <li>general bug fixes</li>
731 <li>updated xmllint man page by John Fleck</li>
732 <li>some VMS and Windows updates</li>
733</ul>
734
Daniel Veillard60087f32001-10-10 09:45:09 +0000[diff] [blame]735<h3>2.4.6: Oct 10 2001</h3>
736<ul>
Daniel Veillard52dcab32001-10-30 12:51:17 +0000[diff] [blame]737 <li>added an updated man pages by John Fleck</li>
Daniel Veillard60087f32001-10-10 09:45:09 +0000[diff] [blame]738 <li>portability and configure fixes</li>
739 <li>an infinite loop on the HTML parser was removed (William)</li>
740 <li>Windows makefile patches from Igor</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]741 <li>fixed half a dozen bugs reported for libxml or libxslt</li>
Daniel Veillard60087f32001-10-10 09:45:09 +0000[diff] [blame]742 <li>updated xmlcatalog to be able to modify SGML super catalogs</li>
743</ul>
744
Daniel Veillarddadd0872001-09-15 09:21:44 +0000[diff] [blame]745<h3>2.4.5: Sep 14 2001</h3>
746<ul>
747 <li>Remove a few annoying bugs in 2.4.4</li>
748 <li>forces the HTML serializer to output decimal charrefs since some
749 version of Netscape can't handle hexadecimal ones</li>
750</ul>
751
752<h3>1.8.16: Sep 14 2001</h3>
753<ul>
754 <li>maintenance release of the old libxml1 branch, couple of bug and
755 portability fixes</li>
756</ul>
757
Daniel Veillard04382ae2001-09-12 18:51:30 +0000[diff] [blame]758<h3>2.4.4: Sep 12 2001</h3>
759<ul>
760 <li>added --convert to xmlcatalog, bug fixes and cleanups of XML
761 Catalog</li>
762 <li>a few bug fixes and some portability changes</li>
763 <li>some documentation cleanups</li>
764</ul>
765
Daniel Veillard39936902001-08-24 00:49:01 +0000[diff] [blame]766<h3>2.4.3: Aug 23 2001</h3>
767<ul>
768 <li>XML Catalog support see the doc</li>
769 <li>New NaN/Infinity floating point code</li>
770 <li>A few bug fixes</li>
771</ul>
772
773<h3>2.4.2: Aug 15 2001</h3>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]774<ul>
775 <li>adds xmlLineNumbersDefault() to control line number generation</li>
776 <li>lot of bug fixes</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]777 <li>the Microsoft MSC projects files should now be up to date</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]778 <li>inheritance of namespaces from DTD defaulted attributes</li>
779 <li>fixes a serious potential security bug</li>
780 <li>added a --format option to xmllint</li>
781</ul>
782
783<h3>2.4.1: July 24 2001</h3>
784<ul>
785 <li>possibility to keep line numbers in the tree</li>
786 <li>some computation NaN fixes</li>
787 <li>extension of the XPath API</li>
788 <li>cleanup for alpha and ia64 targets</li>
789 <li>patch to allow saving through HTTP PUT or POST</li>
Daniel Veillard09ab7e12001-07-10 15:49:44 +0000[diff] [blame]790</ul>
791
792<h3>2.4.0: July 10 2001</h3>
793<ul>
794 <li>Fixed a few bugs in XPath, validation, and tree handling.</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]795 <li>Fixed XML Base implementation, added a couple of examples to the
Daniel Veillard09ab7e12001-07-10 15:49:44 +0000[diff] [blame]796 regression tests</li>
797 <li>A bit of cleanup</li>
Daniel Veillardab8500d2000-10-15 21:06:19 +0000[diff] [blame]798</ul>
799
Daniel Veillard5b43fde2001-07-05 23:31:40 +0000[diff] [blame]800<h3>2.3.14: July 5 2001</h3>
801<ul>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]802 <li>fixed some entities problems and reduce memory requirement when
803 substituting them</li>
Daniel Veillard5b43fde2001-07-05 23:31:40 +0000[diff] [blame]804 <li>lots of improvements in the XPath queries interpreter can be
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]805 substantially faster</li>
Daniel Veillard5b43fde2001-07-05 23:31:40 +0000[diff] [blame]806 <li>Makefiles and configure cleanups</li>
807 <li>Fixes to XPath variable eval, and compare on empty node set</li>
808 <li>HTML tag closing bug fixed</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]809 <li>Fixed an URI reference computation problem when validating</li>
Daniel Veillard5b43fde2001-07-05 23:31:40 +0000[diff] [blame]810</ul>
811
Daniel Veillard2adbb512001-06-28 16:20:36 +0000[diff] [blame]812<h3>2.3.13: June 28 2001</h3>
813<ul>
814 <li>2.3.12 configure.in was broken as well as the push mode XML parser</li>
815 <li>a few more fixes for compilation on Windows MSC by Yon Derek</li>
816</ul>
817
818<h3>1.8.14: June 28 2001</h3>
819<ul>
820 <li>Zbigniew Chyla gave a patch to use the old XML parser in push mode</li>
821 <li>Small Makefile fix</li>
822</ul>
823
Daniel Veillard11648102001-06-26 16:08:24 +0000[diff] [blame]824<h3>2.3.12: June 26 2001</h3>
825<ul>
826 <li>lots of cleanup</li>
827 <li>a couple of validation fix</li>
828 <li>fixed line number counting</li>
829 <li>fixed serious problems in the XInclude processing</li>
830 <li>added support for UTF8 BOM at beginning of entities</li>
831 <li>fixed a strange gcc optimizer bugs in xpath handling of float, gcc-3.0
832 miscompile uri.c (William), Thomas Leitner provided a fix for the
833 optimizer on Tru64</li>
834 <li>incorporated Yon Derek and Igor Zlatkovic fixes and improvements for
835 compilation on Windows MSC</li>
836 <li>update of libxml-doc.el (Felix Natter)</li>
837 <li>fixed 2 bugs in URI normalization code</li>
838</ul>
839
Daniel Veillarde3c81b52001-06-17 14:50:34 +0000[diff] [blame]840<h3>2.3.11: June 17 2001</h3>
841<ul>
842 <li>updates to trio, Makefiles and configure should fix some portability
843 problems (alpha)</li>
844 <li>fixed some HTML serialization problems (pre, script, and block/inline
845 handling), added encoding aware APIs, cleanup of this code</li>
846 <li>added xmlHasNsProp()</li>
847 <li>implemented a specific PI for encoding support in the DocBook SGML
848 parser</li>
849 <li>some XPath fixes (-Infinity, / as a function parameter and namespaces
850 node selection)</li>
851 <li>fixed a performance problem and an error in the validation code</li>
852 <li>fixed XInclude routine to implement the recursive behaviour</li>
853 <li>fixed xmlFreeNode problem when libxml is included statically twice</li>
854 <li>added --version to xmllint for bug reports</li>
855</ul>
856
Daniel Veillard2e4f1882001-06-01 10:11:57 +0000[diff] [blame]857<h3>2.3.10: June 1 2001</h3>
858<ul>
859 <li>fixed the SGML catalog support</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]860 <li>a number of reported bugs got fixed, in XPath, iconv detection,
861 XInclude processing</li>
Daniel Veillard2e4f1882001-06-01 10:11:57 +0000[diff] [blame]862 <li>XPath string function should now handle unicode correctly</li>
863</ul>
864
Daniel Veillard4623acd2001-05-19 15:13:15 +0000[diff] [blame]865<h3>2.3.9: May 19 2001</h3>
866
867<p>Lots of bugfixes, and added a basic SGML catalog support:</p>
868<ul>
869 <li>HTML push bugfix #54891 and another patch from Jonas Borgström</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]870 <li>some serious speed optimization again</li>
Daniel Veillard4623acd2001-05-19 15:13:15 +0000[diff] [blame]871 <li>some documentation cleanups</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]872 <li>trying to get better linking on Solaris (-R)</li>
Daniel Veillard4623acd2001-05-19 15:13:15 +0000[diff] [blame]873 <li>XPath API cleanup from Thomas Broyer</li>
874 <li>Validation bug fixed #54631, added a patch from Gary Pennington, fixed
875 xmlValidGetValidElements()</li>
876 <li>Added an INSTALL file</li>
877 <li>Attribute removal added to API: #54433</li>
878 <li>added a basic support for SGML catalogs</li>
879 <li>fixed xmlKeepBlanksDefault(0) API</li>
880 <li>bugfix in xmlNodeGetLang()</li>
881 <li>fixed a small configure portability problem</li>
882 <li>fixed an inversion of SYSTEM and PUBLIC identifier in HTML document</li>
883</ul>
884
Daniel Veillarda265af72001-05-14 11:13:58 +0000[diff] [blame]885<h3>1.8.13: May 14 2001</h3>
886<ul>
887 <li>bugfixes release of the old libxml1 branch used by Gnome</li>
888</ul>
889
Daniel Veillard3bbbe6f2001-05-03 11:15:37 +0000[diff] [blame]890<h3>2.3.8: May 3 2001</h3>
891<ul>
892 <li>Integrated an SGML DocBook parser for the Gnome project</li>
893 <li>Fixed a few things in the HTML parser</li>
894 <li>Fixed some XPath bugs raised by XSLT use, tried to fix the floating
895 point portability issue</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]896 <li>Speed improvement (8M/s for SAX, 3M/s for DOM, 1.5M/s for
897 DOM+validation using the XML REC as input and a 700MHz celeron).</li>
Daniel Veillard3bbbe6f2001-05-03 11:15:37 +0000[diff] [blame]898 <li>incorporated more Windows cleanup</li>
899 <li>added xmlSaveFormatFile()</li>
900 <li>fixed problems in copying nodes with entities references (gdome)</li>
901 <li>removed some troubles surrounding the new validation module</li>
902</ul>
903
Daniel Veillarda41123c2001-04-22 19:31:20 +0000[diff] [blame]904<h3>2.3.7: April 22 2001</h3>
905<ul>
906 <li>lots of small bug fixes, corrected XPointer</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]907 <li>Non deterministic content model validation support</li>
Daniel Veillarda41123c2001-04-22 19:31:20 +0000[diff] [blame]908 <li>added xmlDocCopyNode for gdome2</li>
909 <li>revamped the way the HTML parser handles end of tags</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]910 <li>XPath: corrections of namespaces support and number formatting</li>
Daniel Veillarda41123c2001-04-22 19:31:20 +0000[diff] [blame]911 <li>Windows: Igor Zlatkovic patches for MSC compilation</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]912 <li>HTML output fixes from P C Chow and William M. Brack</li>
Daniel Veillarda41123c2001-04-22 19:31:20 +0000[diff] [blame]913 <li>Improved validation speed sensible for DocBook</li>
914 <li>fixed a big bug with ID declared in external parsed entities</li>
915 <li>portability fixes, update of Trio from Bjorn Reese</li>
916</ul>
917
Daniel Veillardafc73112001-04-11 11:51:41 +0000[diff] [blame]918<h3>2.3.6: April 8 2001</h3>
919<ul>
920 <li>Code cleanup using extreme gcc compiler warning options, found and
921 cleared half a dozen potential problem</li>
922 <li>the Eazel team found an XML parser bug</li>
923 <li>cleaned up the user of some of the string formatting function. used the
924 trio library code to provide the one needed when the platform is missing
925 them</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]926 <li>xpath: removed a memory leak and fixed the predicate evaluation
927 problem, extended the testsuite and cleaned up the result. XPointer seems
928 broken ...</li>
Daniel Veillardafc73112001-04-11 11:51:41 +0000[diff] [blame]929</ul>
930
Daniel Veillard56a4cb82001-03-24 17:00:36 +0000[diff] [blame]931<h3>2.3.5: Mar 23 2001</h3>
932<ul>
933 <li>Biggest change is separate parsing and evaluation of XPath expressions,
934 there is some new APIs for this too</li>
935 <li>included a number of bug fixes(XML push parser, 51876, notations,
936 52299)</li>
937 <li>Fixed some portability issues</li>
938</ul>
939
Daniel Veillarde356c282001-03-10 12:32:04 +0000[diff] [blame]940<h3>2.3.4: Mar 10 2001</h3>
941<ul>
942 <li>Fixed bugs #51860 and #51861</li>
943 <li>Added a global variable xmlDefaultBufferSize to allow default buffer
944 size to be application tunable.</li>
945 <li>Some cleanup in the validation code, still a bug left and this part
946 should probably be rewritten to support ambiguous content model :-\</li>
947 <li>Fix a couple of serious bugs introduced or raised by changes in 2.3.3
948 parser</li>
949 <li>Fixed another bug in xmlNodeGetContent()</li>
950 <li>Bjorn fixed XPath node collection and Number formatting</li>
951 <li>Fixed a loop reported in the HTML parsing</li>
952 <li>blank space are reported even if the Dtd content model proves that they
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]953 are formatting spaces, this is for XML conformance</li>
Daniel Veillarde356c282001-03-10 12:32:04 +0000[diff] [blame]954</ul>
955
Daniel Veillardb402c072001-03-01 17:28:58 +0000[diff] [blame]956<h3>2.3.3: Mar 1 2001</h3>
957<ul>
958 <li>small change in XPath for XSLT</li>
959 <li>documentation cleanups</li>
960 <li>fix in validation by Gary Pennington</li>
961 <li>serious parsing performances improvements</li>
962</ul>
963
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]964<h3>2.3.2: Feb 24 2001</h3>
Daniel Veillard71681102001-02-24 17:48:53 +0000[diff] [blame]965<ul>
966 <li>chasing XPath bugs, found a bunch, completed some TODO</li>
967 <li>fixed a Dtd parsing bug</li>
968 <li>fixed a bug in xmlNodeGetContent</li>
969 <li>ID/IDREF support partly rewritten by Gary Pennington</li>
970</ul>
971
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]972<h3>2.3.1: Feb 15 2001</h3>
Daniel Veillard6e6a6cc2001-02-15 15:55:44 +0000[diff] [blame]973<ul>
974 <li>some XPath and HTML bug fixes for XSLT</li>
975 <li>small extension of the hash table interfaces for DOM gdome2
976 implementation</li>
977 <li>A few bug fixes</li>
978</ul>
979
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]980<h3>2.3.0: Feb 8 2001 (2.2.12 was on 25 Jan but I didn't kept track)</h3>
Daniel Veillard6e6a6cc2001-02-15 15:55:44 +0000[diff] [blame]981<ul>
982 <li>Lots of XPath bug fixes</li>
983 <li>Add a mode with Dtd lookup but without validation error reporting for
984 XSLT</li>
985 <li>Add support for text node without escaping (XSLT)</li>
986 <li>bug fixes for xmlCheckFilename</li>
987 <li>validation code bug fixes from Gary Pennington</li>
988 <li>Patch from Paul D. Smith correcting URI path normalization</li>
989 <li>Patch to allow simultaneous install of libxml-devel and
990 libxml2-devel</li>
991 <li>the example Makefile is now fixed</li>
992 <li>added HTML to the RPM packages</li>
993 <li>tree copying bugfixes</li>
994 <li>updates to Windows makefiles</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]995 <li>optimization patch from Bjorn Reese</li>
Daniel Veillard6e6a6cc2001-02-15 15:55:44 +0000[diff] [blame]996</ul>
997
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]998<h3>2.2.11: Jan 4 2001</h3>
Daniel Veillard503b8932001-01-05 06:36:31 +0000[diff] [blame]999<ul>
1000 <li>bunch of bug fixes (memory I/O, xpath, ftp/http, ...)</li>
1001 <li>added htmlHandleOmittedElem()</li>
1002 <li>Applied Bjorn Reese's IPV6 first patch</li>
1003 <li>Applied Paul D. Smith patches for validation of XInclude results</li>
Daniel Veillard82687162001-01-22 15:32:01 +0000[diff] [blame]1004 <li>added XPointer xmlns() new scheme support</li>
Daniel Veillard503b8932001-01-05 06:36:31 +0000[diff] [blame]1005</ul>
1006
Daniel Veillard2ddd23d2000-11-25 10:42:19 +0000[diff] [blame]1007<h3>2.2.10: Nov 25 2000</h3>
Daniel Veillard9d343c42000-11-25 10:12:43 +0000[diff] [blame]1008<ul>
1009 <li>Fix the Windows problems of 2.2.8</li>
1010 <li>integrate OpenVMS patches</li>
1011 <li>better handling of some nasty HTML input</li>
1012 <li>Improved the XPointer implementation</li>
1013 <li>integrate a number of provided patches</li>
1014</ul>
1015
Daniel Veillard2ddd23d2000-11-25 10:42:19 +0000[diff] [blame]1016<h3>2.2.9: Nov 25 2000</h3>
1017<ul>
1018 <li>erroneous release :-(</li>
1019</ul>
1020
Daniel Veillard28929b22000-11-13 18:22:49 +0000[diff] [blame]1021<h3>2.2.8: Nov 13 2000</h3>
1022<ul>
1023 <li>First version of <a href="http://www.w3.org/TR/xinclude">XInclude</a>
1024 support</li>
1025 <li>Patch in conditional section handling</li>
1026 <li>updated MS compiler project</li>
1027 <li>fixed some XPath problems</li>
1028 <li>added an URI escaping function</li>
1029 <li>some other bug fixes</li>
1030</ul>
1031
1032<h3>2.2.7: Oct 31 2000</h3>
1033<ul>
1034 <li>added message redirection</li>
1035 <li>XPath improvements (thanks TOM !)</li>
1036 <li>xmlIOParseDTD() added</li>
1037 <li>various small fixes in the HTML, URI, HTTP and XPointer support</li>
1038 <li>some cleanup of the Makefile, autoconf and the distribution content</li>
1039</ul>
1040
Daniel Veillard29a11cc2000-10-25 13:32:39 +0000[diff] [blame]1041<h3>2.2.6: Oct 25 2000:</h3>
1042<ul>
1043 <li>Added an hash table module, migrated a number of internal structure to
1044 those</li>
1045 <li>Fixed a posteriori validation problems</li>
1046 <li>HTTP module cleanups</li>
1047 <li>HTML parser improvements (tag errors, script/style handling, attribute
1048 normalization)</li>
1049 <li>coalescing of adjacent text nodes</li>
1050 <li>couple of XPath bug fixes, exported the internal API</li>
1051</ul>
1052
Daniel Veillardab8500d2000-10-15 21:06:19 +0000[diff] [blame]1053<h3>2.2.5: Oct 15 2000:</h3>
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000[diff] [blame]1054<ul>
Daniel Veillard189446d2000-10-13 10:23:06 +0000[diff] [blame]1055 <li>XPointer implementation and testsuite</li>
1056 <li>Lot of XPath fixes, added variable and functions registration, more
1057 tests</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]1058 <li>Portability fixes, lots of enhancements toward an easy Windows build
1059 and release</li>
Daniel Veillard189446d2000-10-13 10:23:06 +0000[diff] [blame]1060 <li>Late validation fixes</li>
1061 <li>Integrated a lot of contributed patches</li>
1062 <li>added memory management docs</li>
Daniel Veillardab8500d2000-10-15 21:06:19 +0000[diff] [blame]1063 <li>a performance problem when using large buffer seems fixed</li>
Daniel Veillard189446d2000-10-13 10:23:06 +0000[diff] [blame]1064</ul>
1065
1066<h3>2.2.4: Oct 1 2000:</h3>
1067<ul>
1068 <li>main XPath problem fixed</li>
1069 <li>Integrated portability patches for Windows</li>
1070 <li>Serious bug fixes on the URI and HTML code</li>
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]1071</ul>
1072
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]1073<h3>2.2.3: Sep 17 2000</h3>
1074<ul>
1075 <li>bug fixes</li>
1076 <li>cleanup of entity handling code</li>
1077 <li>overall review of all loops in the parsers, all sprintf usage has been
1078 checked too</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1079 <li>Far better handling of larges Dtd. Validating against DocBook XML Dtd
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]1080 works smoothly now.</li>
1081</ul>
1082
1083<h3>1.8.10: Sep 6 2000</h3>
1084<ul>
1085 <li>bug fix release for some Gnome projects</li>
1086</ul>
1087
1088<h3>2.2.2: August 12 2000</h3>
Daniel Veillard786d7c82000-08-12 23:38:57 +0000[diff] [blame]1089<ul>
1090 <li>mostly bug fixes</li>
Daniel Veillardec78c0f2000-08-25 10:25:23 +0000[diff] [blame]1091 <li>started adding routines to access xml parser context options</li>
Daniel Veillard786d7c82000-08-12 23:38:57 +0000[diff] [blame]1092</ul>
1093
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]1094<h3>2.2.1: July 21 2000</h3>
Daniel Veillarda2679fa2000-07-22 02:38:15 +0000[diff] [blame]1095<ul>
1096 <li>a purely bug fixes release</li>
1097 <li>fixed an encoding support problem when parsing from a memory block</li>
1098 <li>fixed a DOCTYPE parsing problem</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]1099 <li>removed a bug in the function allowing to override the memory
1100 allocation routines</li>
Daniel Veillarda2679fa2000-07-22 02:38:15 +0000[diff] [blame]1101</ul>
1102
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]1103<h3>2.2.0: July 14 2000</h3>
Daniel Veillard94e90602000-07-17 14:38:19 +0000[diff] [blame]1104<ul>
1105 <li>applied a lot of portability fixes</li>
1106 <li>better encoding support/cleanup and saving (content is now always
1107 encoded in UTF-8)</li>
1108 <li>the HTML parser now correctly handles encodings</li>
1109 <li>added xmlHasProp()</li>
1110 <li>fixed a serious problem with &amp;#38;</li>
1111 <li>propagated the fix to FTP client</li>
1112 <li>cleanup, bugfixes, etc ...</li>
1113 <li>Added a page about <a href="encoding.html">libxml Internationalization
1114 support</a></li>
1115</ul>
1116
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1117<h3>1.8.9: July 9 2000</h3>
1118<ul>
1119 <li>fixed the spec the RPMs should be better</li>
1120 <li>fixed a serious bug in the FTP implementation, released 1.8.9 to solve
1121 rpmfind users problem</li>
1122</ul>
1123
Daniel Veillard6388e172000-07-03 16:07:19 +0000[diff] [blame]1124<h3>2.1.1: July 1 2000</h3>
1125<ul>
1126 <li>fixes a couple of bugs in the 2.1.0 packaging</li>
1127 <li>improvements on the HTML parser</li>
1128</ul>
1129
Daniel Veillard3f6f7f62000-06-30 17:58:25 +0000[diff] [blame]1130<h3>2.1.0 and 1.8.8: June 29 2000</h3>
1131<ul>
Daniel Veillardc0801af2002-05-28 16:28:42 +0000[diff] [blame]1132 <li>1.8.8 is mostly a commodity package for upgrading to libxml2 according
1133 to <a href="upgrade.html">new instructions</a>. It fixes a nasty problem
Daniel Veillard3f6f7f62000-06-30 17:58:25 +0000[diff] [blame]1134 about &amp;#38; charref parsing</li>
1135 <li>2.1.0 also ease the upgrade from libxml v1 to the recent version. it
1136 also contains numerous fixes and enhancements:
1137 <ul>
1138 <li>added xmlStopParser() to stop parsing</li>
1139 <li>improved a lot parsing speed when there is large CDATA blocs</li>
1140 <li>includes XPath patches provided by Picdar Technology</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1141 <li>tried to fix as much as possible DTD validation and namespace
Daniel Veillard3f6f7f62000-06-30 17:58:25 +0000[diff] [blame]1142 related problems</li>
1143 <li>output to a given encoding has been added/tested</li>
1144 <li>lot of various fixes</li>
1145 </ul>
1146 </li>
1147</ul>
1148
Daniel Veillarde0aed302000-04-16 08:52:20 +0000[diff] [blame]1149<h3>2.0.0: Apr 12 2000</h3>
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]1150<ul>
1151 <li>First public release of libxml2. If you are using libxml, it's a good
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1152 idea to check the 1.x to 2.x upgrade instructions. NOTE: while initially
1153 scheduled for Apr 3 the release occurred only on Apr 12 due to massive
Daniel Veillarde0aed302000-04-16 08:52:20 +0000[diff] [blame]1154 workload.</li>
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]1155 <li>The include are now located under $prefix/include/libxml (instead of
Daniel Veillarde0aed302000-04-16 08:52:20 +0000[diff] [blame]1156 $prefix/include/gnome-xml), they also are referenced by
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1157 <pre>#include &lt;libxml/xxx.h&gt;</pre>
Daniel Veillarde0aed302000-04-16 08:52:20 +0000[diff] [blame]1158 <p>instead of</p>
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]1159 <pre>#include "xxx.h"</pre>
1160 </li>
Daniel Veillard8f621982000-03-20 13:07:15 +0000[diff] [blame]1161 <li>a new URI module for parsing URIs and following strictly RFC 2396</li>
1162 <li>the memory allocation routines used by libxml can now be overloaded
1163 dynamically by using xmlMemSetup()</li>
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]1164 <li>The previously CVS only tool tester has been renamed
1165 <strong>xmllint</strong> and is now installed as part of the libxml2
1166 package</li>
Daniel Veillarde0aed302000-04-16 08:52:20 +0000[diff] [blame]1167 <li>The I/O interface has been revamped. There is now ways to plug in
1168 specific I/O modules, either at the URI scheme detection level using
1169 xmlRegisterInputCallbacks() or by passing I/O functions when creating a
1170 parser context using xmlCreateIOParserCtxt()</li>
1171 <li>there is a C preprocessor macro LIBXML_VERSION providing the version
1172 number of the libxml module in use</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]1173 <li>a number of optional features of libxml can now be excluded at
1174 configure time (FTP/HTTP/HTML/XPath/Debug)</li>
Daniel Veillardedfb29b2000-03-14 19:59:05 +0000[diff] [blame]1175</ul>
1176
1177<h3>2.0.0beta: Mar 14 2000</h3>
1178<ul>
1179 <li>This is a first Beta release of libxml version 2</li>
Daniel Veillarde356c282001-03-10 12:32:04 +0000[diff] [blame]1180 <li>It's available only from<a href="ftp://xmlsoft.org/">xmlsoft.org
1181 FTP</a>, it's packaged as libxml2-2.0.0beta and available as tar and
1182 RPMs</li>
Daniel Veillardedfb29b2000-03-14 19:59:05 +0000[diff] [blame]1183 <li>This version is now the head in the Gnome CVS base, the old one is
1184 available under the tag LIB_XML_1_X</li>
Daniel Veillardc0801af2002-05-28 16:28:42 +0000[diff] [blame]1185 <li>This includes a very large set of changes. From a programmatic point
1186 of view applications should not have to be modified too much, check the
1187 <a href="upgrade.html">upgrade page</a></li>
Daniel Veillardedfb29b2000-03-14 19:59:05 +0000[diff] [blame]1188 <li>Some interfaces may changes (especially a bit about encoding).</li>
1189 <li>the updates includes:
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]1190 <ul>
Daniel Veillardedfb29b2000-03-14 19:59:05 +0000[diff] [blame]1191 <li>fix I18N support. ISO-Latin-x/UTF-8/UTF-16 (nearly) seems correctly
1192 handled now</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1193 <li>Better handling of entities, especially well-formedness checking
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]1194 and proper PEref extensions in external subsets</li>
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]1195 <li>DTD conditional sections</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1196 <li>Validation now correctly handle entities content</li>
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]1197 <li><a href="http://rpmfind.net/tools/gdome/messages/0039.html">change
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1198 structures to accommodate DOM</a></li>
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]1199 </ul>
1200 </li>
Daniel Veillardedfb29b2000-03-14 19:59:05 +0000[diff] [blame]1201 <li>Serious progress were made toward compliance, <a
1202 href="conf/result.html">here are the result of the test</a> against the
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1203 OASIS testsuite (except the Japanese tests since I don't support that
Daniel Veillardedfb29b2000-03-14 19:59:05 +0000[diff] [blame]1204 encoding yet). This URL is rebuilt every couple of hours using the CVS
1205 head version.</li>
Daniel Veillarde41f2b72000-01-30 20:00:07 +0000[diff] [blame]1206</ul>
1207
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1208<h3>1.8.7: Mar 6 2000</h3>
1209<ul>
1210 <li>This is a bug fix release:</li>
1211 <li>It is possible to disable the ignorable blanks heuristic used by
1212 libxml-1.x, a new function xmlKeepBlanksDefault(0) will allow this. Note
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]1213 that for adherence to XML spec, this behaviour will be disabled by
1214 default in 2.x . The same function will allow to keep compatibility for
1215 old code.</li>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1216 <li>Blanks in &lt;a&gt; &lt;/a&gt; constructs are not ignored anymore,
1217 avoiding heuristic is really the Right Way :-\</li>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1218 <li>The unchecked use of snprintf which was breaking libxml-1.8.6
1219 compilation on some platforms has been fixed</li>
1220 <li>nanoftp.c nanohttp.c: Fixed '#' and '?' stripping when processing
1221 URIs</li>
1222</ul>
1223
Daniel Veillarde41f2b72000-01-30 20:00:07 +0000[diff] [blame]1224<h3>1.8.6: Jan 31 2000</h3>
1225<ul>
1226 <li>added a nanoFTP transport module, debugged until the new version of <a
1227 href="http://rpmfind.net/linux/rpm2html/rpmfind.html">rpmfind</a> can use
1228 it without troubles</li>
Daniel Veillardda07c342000-01-25 18:31:22 +0000[diff] [blame]1229</ul>
1230
1231<h3>1.8.5: Jan 21 2000</h3>
1232<ul>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]1233 <li>adding APIs to parse a well balanced chunk of XML (production <a
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]1234 href="http://www.w3.org/TR/REC-xml#NT-content">[43] content</a> of the
1235 XML spec)</li>
Daniel Veillard461a66c2000-01-18 18:01:01 +0000[diff] [blame]1236 <li>fixed a hideous bug in xmlGetProp pointed by Rune.Djurhuus@fast.no</li>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1237 <li>Jody Goldberg &lt;jgoldberg@home.com&gt; provided another patch trying
1238 to solve the zlib checks problems</li>
Daniel Veillard461a66c2000-01-18 18:01:01 +0000[diff] [blame]1239 <li>The current state in gnome CVS base is expected to ship as 1.8.5 with
1240 gnumeric soon</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]1241</ul>
1242
1243<h3>1.8.4: Jan 13 2000</h3>
1244<ul>
1245 <li>bug fixes, reintroduced xmlNewGlobalNs(), fixed xmlNewNs()</li>
1246 <li>all exit() call should have been removed from libxml</li>
1247 <li>fixed a problem with INCLUDE_WINSOCK on WIN32 platform</li>
1248 <li>added newDocFragment()</li>
Daniel Veillardf84f71f2000-01-05 19:54:23 +0000[diff] [blame]1249</ul>
1250
1251<h3>1.8.3: Jan 5 2000</h3>
1252<ul>
1253 <li>a Push interface for the XML and HTML parsers</li>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1254 <li>a shell-like interface to the document tree (try tester --shell :-)</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1255 <li>lots of bug fixes and improvement added over XMas holidays</li>
Daniel Veillard437b87b2000-01-03 17:30:46 +0000[diff] [blame]1256 <li>fixed the DTD parsing code to work with the xhtml DTD</li>
Daniel Veillardf84f71f2000-01-05 19:54:23 +0000[diff] [blame]1257 <li>added xmlRemoveProp(), xmlRemoveID() and xmlRemoveRef()</li>
1258 <li>Fixed bugs in xmlNewNs()</li>
Daniel Veillard437b87b2000-01-03 17:30:46 +0000[diff] [blame]1259 <li>External entity loading code has been revamped, now it uses
Daniel Veillardf84f71f2000-01-05 19:54:23 +0000[diff] [blame]1260 xmlLoadExternalEntity(), some fix on entities processing were added</li>
Daniel Veillard437b87b2000-01-03 17:30:46 +0000[diff] [blame]1261 <li>cleaned up WIN32 includes of socket stuff</li>
Daniel Veillard5cb5ab81999-12-21 15:35:29 +0000[diff] [blame]1262</ul>
1263
1264<h3>1.8.2: Dec 21 1999</h3>
1265<ul>
Daniel Veillardb24054a1999-12-18 15:32:46 +0000[diff] [blame]1266 <li>I got another problem with includes and C++, I hope this issue is fixed
1267 for good this time</li>
Daniel Veillard5cb5ab81999-12-21 15:35:29 +0000[diff] [blame]1268 <li>Added a few tree modification functions: xmlReplaceNode,
1269 xmlAddPrevSibling, xmlAddNextSibling, xmlNodeSetName and
1270 xmlDocSetRootElement</li>
1271 <li>Tried to improve the HTML output with help from <a
1272 href="mailto:clahey@umich.edu">Chris Lahey</a></li>
Daniel Veillarde4e51311999-12-18 15:32:46 +0000[diff] [blame]1273</ul>
Daniel Veillardb24054a1999-12-18 15:32:46 +0000[diff] [blame]1274
Daniel Veillarde4e51311999-12-18 15:32:46 +0000[diff] [blame]1275<h3>1.8.1: Dec 18 1999</h3>
1276<ul>
1277 <li>various patches to avoid troubles when using libxml with C++ compilers
1278 the "namespace" keyword and C escaping in include files</li>
1279 <li>a problem in one of the core macros IS_CHAR was corrected</li>
1280 <li>fixed a bug introduced in 1.8.0 breaking default namespace processing,
1281 and more specifically the Dia application</li>
Daniel Veillard944b5ff1999-12-15 19:08:24 +0000[diff] [blame]1282 <li>fixed a posteriori validation (validation after parsing, or by using a
1283 Dtd not specified in the original document)</li>
Daniel Veillardb24054a1999-12-18 15:32:46 +0000[diff] [blame]1284 <li>fixed a bug in</li>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]1285</ul>
1286
1287<h3>1.8.0: Dec 12 1999</h3>
1288<ul>
1289 <li>cleanup, especially memory wise</li>
1290 <li>the parser should be more reliable, especially the HTML one, it should
1291 not crash, whatever the input !</li>
1292 <li>Integrated various patches, especially a speedup improvement for large
1293 dataset from <a href="mailto:cnygard@bellatlantic.net">Carl Nygard</a>,
1294 configure with --with-buffers to enable them.</li>
1295 <li>attribute normalization, oops should have been added long ago !</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1296 <li>attributes defaulted from DTDs should be available, xmlSetProp() now
1297 does entities escaping by default.</li>
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000[diff] [blame]1298</ul>
Daniel Veillard35008381999-10-25 13:15:52 +0000[diff] [blame]1299
1300<h3>1.7.4: Oct 25 1999</h3>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]1301<ul>
Daniel Veillard35008381999-10-25 13:15:52 +0000[diff] [blame]1302 <li>Lots of HTML improvement</li>
1303 <li>Fixed some errors when saving both XML and HTML</li>
1304 <li>More examples, the regression tests should now look clean</li>
1305 <li>Fixed a bug with contiguous charref</li>
1306</ul>
1307
1308<h3>1.7.3: Sep 29 1999</h3>
1309<ul>
1310 <li>portability problems fixed</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1311 <li>snprintf was used unconditionally, leading to link problems on system
Daniel Veillard35008381999-10-25 13:15:52 +0000[diff] [blame]1312 were it's not available, fixed</li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]1313</ul>
1314
1315<h3>1.7.1: Sep 24 1999</h3>
1316<ul>
1317 <li>The basic type for strings manipulated by libxml has been renamed in
1318 1.7.1 from <strong>CHAR</strong> to <strong>xmlChar</strong>. The reason
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]1319 is that CHAR was conflicting with a predefined type on Windows. However
1320 on non WIN32 environment, compatibility is provided by the way of a
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]1321 <strong>#define </strong>.</li>
1322 <li>Changed another error : the use of a structure field called errno, and
1323 leading to troubles on platforms where it's a macro</li>
1324</ul>
1325
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1326<h3>1.7.0: Sep 23 1999</h3>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]1327<ul>
1328 <li>Added the ability to fetch remote DTD or parsed entities, see the <a
Daniel Veillard9cb5ff42001-01-29 08:22:21 +0000[diff] [blame]1329 href="html/libxml-nanohttp.html">nanohttp</a> module.</li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]1330 <li>Added an errno to report errors by another mean than a simple printf
1331 like callback</li>
1332 <li>Finished ID/IDREF support and checking when validation</li>
1333 <li>Serious memory leaks fixed (there is now a <a
Daniel Veillard9cb5ff42001-01-29 08:22:21 +0000[diff] [blame]1334 href="html/libxml-xmlmemory.html">memory wrapper</a> module)</li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]1335 <li>Improvement of <a href="http://www.w3.org/TR/xpath">XPath</a>
1336 implementation</li>
1337 <li>Added an HTML parser front-end</li>
1338</ul>
1339
1340<h2><a name="XML">XML</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1341
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]1342<p><a href="http://www.w3.org/TR/REC-xml">XML is a standard</a> for
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1343markup-based structured documents. Here is <a name="example">an example XML
1344document</a>:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1345<pre>&lt;?xml version="1.0"?&gt;
1346&lt;EXAMPLE prop1="gnome is great" prop2="&amp;amp; linux too"&gt;
1347 &lt;head&gt;
1348 &lt;title&gt;Welcome to Gnome&lt;/title&gt;
1349 &lt;/head&gt;
1350 &lt;chapter&gt;
1351 &lt;title&gt;The Linux adventure&lt;/title&gt;
1352 &lt;p&gt;bla bla bla ...&lt;/p&gt;
1353 &lt;image href="linus.gif"/&gt;
1354 &lt;p&gt;...&lt;/p&gt;
1355 &lt;/chapter&gt;
1356&lt;/EXAMPLE&gt;</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1357
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]1358<p>The first line specifies that it's an XML document and gives useful
1359information about its encoding. Then the document is a text format whose
1360structure is specified by tags between brackets. <strong>Each tag opened has
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1361to be closed</strong>. XML is pedantic about this. However, if a tag is empty
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]1362(no content), a single tag can serve as both the opening and closing tag if
1363it ends with <code>/&gt;</code> rather than with <code>&gt;</code>. Note
1364that, for example, the image tag has no content (just an attribute) and is
1365closed by ending the tag with <code>/&gt;</code>.</p>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]1366
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1367<p>XML can be applied successfully to a wide range of uses, from long term
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]1368structured document maintenance (where it follows the steps of SGML) to
1369simple data encoding mechanisms like configuration file formatting (glade),
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1370spreadsheets (gnumeric), or even shorter lived documents such as WebDAV where
1371it is used to encode remote calls between a client and a server.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1372
Daniel Veillard82687162001-01-22 15:32:01 +0000[diff] [blame]1373<h2><a name="XSLT">XSLT</a></h2>
1374
Daniel Veillard6e6a6cc2001-02-15 15:55:44 +0000[diff] [blame]1375<p>Check <a href="http://xmlsoft.org/XSLT">the separate libxslt page</a></p>
1376
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]1377<p><a href="http://www.w3.org/TR/xslt">XSL Transformations</a>, is a
1378language for transforming XML documents into other XML documents (or
1379HTML/textual output).</p>
Daniel Veillard82687162001-01-22 15:32:01 +0000[diff] [blame]1380
1381<p>A separate library called libxslt is being built on top of libxml2. This
1382module "libxslt" can be found in the Gnome CVS base too.</p>
1383
Daniel Veillard383b1472001-01-23 11:39:52 +0000[diff] [blame]1384<p>You can check the <a
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]1385href="http://cvs.gnome.org/lxr/source/libxslt/FEATURES">features</a>
1386supported and the progresses on the <a
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1387href="http://cvs.gnome.org/lxr/source/libxslt/ChangeLog"
1388name="Changelog">Changelog</a></p>
1389
1390<h2><a name="Python">Python and bindings</a></h2>
1391
1392<p>There is a number of language bindings and wrappers available for libxml2,
1393the list below is not exhaustive. Please contact the <a
1394href="http://mail.gnome.org/mailman/listinfo/xml-bindings">xml-bindings@gnome.org</a>
1395(<a href="http://mail.gnome.org/archives/xml-bindings/">archives</a>) in
1396order to get updates to this list or to discuss the specific topic of libxml2
1397or libxslt wrappers or bindings:</p>
1398<ul>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]1399 <li><a href="mailto:ari@lusis.org">Ari Johnson</a> provides a C++ wrapper
1400 for libxml:<br>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1401 Website: <a
1402 href="http://lusis.org/~ari/xml++/">http://lusis.org/~ari/xml++/</a><br>
1403 Download: <a
1404 href="http://lusis.org/~ari/xml++/libxml++.tar.gz">http://lusis.org/~ari/xml++/libxml++.tar.gz</a></li>
1405 <li>There is another <a href="http://libgdome-cpp.berlios.de/">C++ wrapper
1406 based on the gdome2 </a>bindings maintained by Tobias Peters.</li>
Daniel Veillard9b6fd302002-05-13 12:06:47 +0000[diff] [blame]1407 <li>and a third C++ wrapper by Peter Jones &lt;pjones@pmade.org&gt;
1408 <p>Website: <a
1409 href="http://pmade.org/pjones/software/xmlwrapp/">http://pmade.org/pjones/software/xmlwrapp/</a></p>
1410 </li>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1411 <li><a
1412 href="http://mail.gnome.org/archives/xml/2001-March/msg00014.html">Matt
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1413 Sergeant</a> developed <a
1414 href="http://axkit.org/download/">XML::LibXSLT</a>, a Perl wrapper for
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]1415 libxml2/libxslt as part of the <a href="http://axkit.com/">AxKit XML
1416 application server</a></li>
Daniel Veillard21473672002-06-17 07:29:22 +0000[diff] [blame]1417 <li><a href="mailto:dkuhlman@cutter.rexx.com">Dave Kuhlman</a> provides an
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]1418 earlier version of the libxml/libxslt <a
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1419 href="http://www.rexx.com/~dkuhlman">wrappers for Python</a></li>
Daniel Veillard21473672002-06-17 07:29:22 +0000[diff] [blame]1420 <li>Gopal.V and Peter Minten develop <a
1421 href="http://savannah.gnu.org/projects/libxmlsharp">libxml#</a>, a set of
1422 C# libxml2 bindings</li>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1423 <li>Petr Kozelka provides <a
1424 href="http://sourceforge.net/projects/libxml2-pas">Pascal units to glue
1425 libxml2</a> with Kylix, Delphi and other Pascal compilers</li>
Daniel Veillardb2fb8ed2002-04-01 09:33:12 +0000[diff] [blame]1426 <li>Uwe Fechner also provides <a
1427 href="http://sourceforge.net/projects/idom2-pas/">idom2</a>, a DOM2
Daniel Veillard75794822002-04-11 16:24:32 +0000[diff] [blame]1428 implementation for Kylix2/D5/D6 from Borland</li>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1429 <li>Wai-Sun "Squidster" Chia provides <a
1430 href="http://www.rubycolor.org/arc/redist/">bindings for Ruby</a> and
1431 libxml2 bindings are also available in Ruby through the <a
1432 href="http://libgdome-ruby.berlios.de/">libgdome-ruby</a> module
1433 maintained by Tobias Peters.</li>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]1434 <li>Steve Ball and contributors maintains <a
1435 href="http://tclxml.sourceforge.net/">libxml2 and libxslt bindings for
1436 Tcl</a></li>
1437 <li>There is support for libxml2 in the DOM module of PHP.</li>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1438</ul>
1439
Daniel Veillardc0801af2002-05-28 16:28:42 +0000[diff] [blame]1440<p>The distribution includes a set of Python bindings, which are guaranteed
1441to be maintained as part of the library in the future, though the Python
Daniel Veillard0b79dfe2002-02-23 13:02:31 +0000[diff] [blame]1442interface have not yet reached the maturity of the C API.</p>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]1443
1444<p>To install the Python bindings there are 2 options:</p>
Daniel Veillard0b79dfe2002-02-23 13:02:31 +0000[diff] [blame]1445<ul>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]1446 <li>If you use an RPM based distribution, simply install the <a
1447 href="http://rpmfind.net/linux/rpm2html/search.php?query=libxml2-python">libxml2-python
1448 RPM</a> (and if needed the <a
1449 href="http://rpmfind.net/linux/rpm2html/search.php?query=libxslt-python">libxslt-python
1450 RPM</a>).</li>
1451 <li>Otherwise use the <a href="ftp://xmlsoft.org/python/">libxml2-python
1452 module distribution</a> corresponding to your installed version of
1453 libxml2 and libxslt. Note that to install it you will need both libxml2
1454 and libxslt installed and run "python setup.py build install" in the
1455 module tree.</li>
Daniel Veillard0b79dfe2002-02-23 13:02:31 +0000[diff] [blame]1456</ul>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]1457
1458<p>The distribution includes a set of examples and regression tests for the
1459python bindings in the <code>python/tests</code> directory. Here are some
1460excepts from those tests:</p>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1461
1462<h3>tst.py:</h3>
1463
1464<p>This is a basic test of the file interface and DOM navigation:</p>
1465<pre>import libxml2
1466
1467doc = libxml2.parseFile("tst.xml")
1468if doc.name != "tst.xml":
1469 print "doc.name failed"
1470 sys.exit(1)
1471root = doc.children
1472if root.name != "doc":
1473 print "root.name failed"
1474 sys.exit(1)
1475child = root.children
1476if child.name != "foo":
1477 print "child.name failed"
1478 sys.exit(1)
1479doc.freeDoc()</pre>
1480
1481<p>The Python module is called libxml2, parseFile is the equivalent of
1482xmlParseFile (most of the bindings are automatically generated, and the xml
1483prefix is removed and the casing convention are kept). All node seen at the
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1484binding level share the same subset of accessors:</p>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1485<ul>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]1486 <li><code>name</code> : returns the node name</li>
Daniel Veillardc0801af2002-05-28 16:28:42 +0000[diff] [blame]1487 <li><code>type</code> : returns a string indicating the node type</li>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]1488 <li><code>content</code> : returns the content of the node, it is based on
1489 xmlNodeGetContent() and hence is recursive.</li>
1490 <li><code>parent</code> , <code>children</code>, <code>last</code>,
1491 <code>next</code>, <code>prev</code>, <code>doc</code>,
1492 <code>properties</code>: pointing to the associated element in the tree,
1493 those may return None in case no such link exists.</li>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1494</ul>
1495
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1496<p>Also note the need to explicitly deallocate documents with freeDoc() .
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1497Reference counting for libxml2 trees would need quite a lot of work to
1498function properly, and rather than risk memory leaks if not implemented
1499correctly it sounds safer to have an explicit function to free a tree. The
1500wrapper python objects like doc, root or child are them automatically garbage
1501collected.</p>
1502
1503<h3>validate.py:</h3>
1504
1505<p>This test check the validation interfaces and redirection of error
1506messages:</p>
1507<pre>import libxml2
1508
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1509#deactivate error messages from the validation
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1510def noerr(ctx, str):
1511 pass
1512
1513libxml2.registerErrorHandler(noerr, None)
1514
1515ctxt = libxml2.createFileParserCtxt("invalid.xml")
1516ctxt.validate(1)
1517ctxt.parseDocument()
1518doc = ctxt.doc()
1519valid = ctxt.isValid()
1520doc.freeDoc()
1521if valid != 0:
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1522 print "validity check failed"</pre>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1523
1524<p>The first thing to notice is the call to registerErrorHandler(), it
1525defines a new error handler global to the library. It is used to avoid seeing
1526the error messages when trying to validate the invalid document.</p>
1527
1528<p>The main interest of that test is the creation of a parser context with
1529createFileParserCtxt() and how the behaviour can be changed before calling
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1530parseDocument() . Similarly the informations resulting from the parsing phase
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1531are also available using context methods.</p>
1532
1533<p>Contexts like nodes are defined as class and the libxml2 wrappers maps the
1534C function interfaces in terms of objects method as much as possible. The
1535best to get a complete view of what methods are supported is to look at the
1536libxml2.py module containing all the wrappers.</p>
1537
1538<h3>push.py:</h3>
1539
1540<p>This test show how to activate the push parser interface:</p>
1541<pre>import libxml2
1542
1543ctxt = libxml2.createPushParser(None, "&lt;foo", 4, "test.xml")
1544ctxt.parseChunk("/&gt;", 2, 1)
1545doc = ctxt.doc()
1546
1547doc.freeDoc()</pre>
1548
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1549<p>The context is created with a special call based on the
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1550xmlCreatePushParser() from the C library. The first argument is an optional
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1551SAX callback object, then the initial set of data, the length and the name of
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1552the resource in case URI-References need to be computed by the parser.</p>
1553
1554<p>Then the data are pushed using the parseChunk() method, the last call
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1555setting the third argument terminate to 1.</p>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1556
1557<h3>pushSAX.py:</h3>
1558
1559<p>this test show the use of the event based parsing interfaces. In this case
1560the parser does not build a document, but provides callback information as
1561the parser makes progresses analyzing the data being provided:</p>
1562<pre>import libxml2
1563log = ""
1564
1565class callback:
1566 def startDocument(self):
1567 global log
1568 log = log + "startDocument:"
1569
1570 def endDocument(self):
1571 global log
1572 log = log + "endDocument:"
1573
1574 def startElement(self, tag, attrs):
1575 global log
1576 log = log + "startElement %s %s:" % (tag, attrs)
1577
1578 def endElement(self, tag):
1579 global log
1580 log = log + "endElement %s:" % (tag)
1581
1582 def characters(self, data):
1583 global log
1584 log = log + "characters: %s:" % (data)
1585
1586 def warning(self, msg):
1587 global log
1588 log = log + "warning: %s:" % (msg)
1589
1590 def error(self, msg):
1591 global log
1592 log = log + "error: %s:" % (msg)
1593
1594 def fatalError(self, msg):
1595 global log
1596 log = log + "fatalError: %s:" % (msg)
1597
1598handler = callback()
1599
1600ctxt = libxml2.createPushParser(handler, "&lt;foo", 4, "test.xml")
1601chunk = " url='tst'&gt;b"
1602ctxt.parseChunk(chunk, len(chunk), 0)
1603chunk = "ar&lt;/foo&gt;"
1604ctxt.parseChunk(chunk, len(chunk), 1)
1605
Daniel Veillardfcbfa2d2002-02-21 17:54:27 +0000[diff] [blame]1606reference = "startDocument:startElement foo {'url': 'tst'}:" + \
1607 "characters: bar:endElement foo:endDocument:"
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1608if log != reference:
1609 print "Error got: %s" % log
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1610 print "Expected: %s" % reference</pre>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1611
1612<p>The key object in that test is the handler, it provides a number of entry
1613points which can be called by the parser as it makes progresses to indicate
1614the information set obtained. The full set of callback is larger than what
1615the callback class in that specific example implements (see the SAX
1616definition for a complete list). The wrapper will only call those supplied by
1617the object when activated. The startElement receives the names of the element
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1618and a dictionary containing the attributes carried by this element.</p>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1619
1620<p>Also note that the reference string generated from the callback shows a
1621single character call even though the string "bar" is passed to the parser
1622from 2 different call to parseChunk()</p>
1623
1624<h3>xpath.py:</h3>
1625
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1626<p>This is a basic test of XPath wrappers support</p>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1627<pre>import libxml2
1628
1629doc = libxml2.parseFile("tst.xml")
1630ctxt = doc.xpathNewContext()
1631res = ctxt.xpathEval("//*")
1632if len(res) != 2:
1633 print "xpath query: wrong node set size"
1634 sys.exit(1)
1635if res[0].name != "doc" or res[1].name != "foo":
1636 print "xpath query: wrong node set value"
1637 sys.exit(1)
1638doc.freeDoc()
1639ctxt.xpathFreeContext()</pre>
1640
1641<p>This test parses a file, then create an XPath context to evaluate XPath
1642expression on it. The xpathEval() method execute an XPath query and returns
1643the result mapped in a Python way. String and numbers are natively converted,
1644and node sets are returned as a tuple of libxml2 Python nodes wrappers. Like
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1645the document, the XPath context need to be freed explicitly, also not that
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1646the result of the XPath query may point back to the document tree and hence
1647the document must be freed after the result of the query is used.</p>
1648
1649<h3>xpathext.py:</h3>
1650
1651<p>This test shows how to extend the XPath engine with functions written in
1652python:</p>
1653<pre>import libxml2
1654
1655def foo(ctx, x):
1656 return x + 1
1657
1658doc = libxml2.parseFile("tst.xml")
1659ctxt = doc.xpathNewContext()
1660libxml2.registerXPathFunction(ctxt._o, "foo", None, foo)
1661res = ctxt.xpathEval("foo(1)")
1662if res != 2:
1663 print "xpath extension failure"
1664doc.freeDoc()
1665ctxt.xpathFreeContext()</pre>
1666
1667<p>Note how the extension function is registered with the context (but that
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1668part is not yet finalized, this may change slightly in the future).</p>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1669
1670<h3>tstxpath.py:</h3>
1671
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1672<p>This test is similar to the previous one but shows how the extension
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1673function can access the XPath evaluation context:</p>
1674<pre>def foo(ctx, x):
1675 global called
1676
1677 #
1678 # test that access to the XPath evaluation contexts
1679 #
1680 pctxt = libxml2.xpathParserContext(_obj=ctx)
1681 ctxt = pctxt.context()
1682 called = ctxt.function()
1683 return x + 1</pre>
1684
1685<p>All the interfaces around the XPath parser(or rather evaluation) context
1686are not finalized, but it should be sufficient to do contextual work at the
1687evaluation point.</p>
1688
1689<h3>Memory debugging:</h3>
1690
1691<p>last but not least, all tests starts with the following prologue:</p>
1692<pre>#memory debug specific
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]1693libxml2.debugMemory(1)</pre>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1694
1695<p>and ends with the following epilogue:</p>
1696<pre>#memory debug specific
1697libxml2.cleanupParser()
1698if libxml2.debugMemory(1) == 0:
1699 print "OK"
1700else:
1701 print "Memory leak %d bytes" % (libxml2.debugMemory(1))
1702 libxml2.dumpMemory()</pre>
1703
1704<p>Those activate the memory debugging interface of libxml2 where all
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1705allocated block in the library are tracked. The prologue then cleans up the
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1706library state and checks that all allocated memory has been freed. If not it
1707calls dumpMemory() which saves that list in a <code>.memdump</code> file.</p>
Daniel Veillard82687162001-01-22 15:32:01 +0000[diff] [blame]1708
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]1709<h2><a name="architecture">libxml architecture</a></h2>
Daniel Veillard4540be42000-08-19 16:40:28 +0000[diff] [blame]1710
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]1711<p>Libxml is made of multiple components; some of them are optional, and most
1712of the block interfaces are public. The main components are:</p>
Daniel Veillard4540be42000-08-19 16:40:28 +0000[diff] [blame]1713<ul>
1714 <li>an Input/Output layer</li>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]1715 <li>FTP and HTTP client layers (optional)</li>
Daniel Veillard4540be42000-08-19 16:40:28 +0000[diff] [blame]1716 <li>an Internationalization layer managing the encodings support</li>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]1717 <li>a URI module</li>
Daniel Veillard4540be42000-08-19 16:40:28 +0000[diff] [blame]1718 <li>the XML parser and its basic SAX interface</li>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]1719 <li>an HTML parser using the same SAX interface (optional)</li>
Daniel Veillard4540be42000-08-19 16:40:28 +0000[diff] [blame]1720 <li>a SAX tree module to build an in-memory DOM representation</li>
1721 <li>a tree module to manipulate the DOM representation</li>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]1722 <li>a validation module using the DOM representation (optional)</li>
Daniel Veillard4540be42000-08-19 16:40:28 +0000[diff] [blame]1723 <li>an XPath module for global lookup in a DOM representation
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]1724 (optional)</li>
1725 <li>a debug module (optional)</li>
Daniel Veillard4540be42000-08-19 16:40:28 +0000[diff] [blame]1726</ul>
1727
1728<p>Graphically this gives the following:</p>
1729
1730<p><img src="libxml.gif" alt="a graphical view of the various"></p>
1731
1732<p></p>
1733
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]1734<h2><a name="tree">The tree output</a></h2>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1735
1736<p>The parser returns a tree built during the document analysis. The value
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]1737returned is an <strong>xmlDocPtr</strong> (i.e., a pointer to an
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1738<strong>xmlDoc</strong> structure). This structure contains information such
Daniel Veillard306be992000-07-03 12:38:45 +0000[diff] [blame]1739as the file name, the document type, and a <strong>children</strong> pointer
1740which is the root of the document (or more exactly the first child under the
1741root which is the document). The tree is made of <strong>xmlNode</strong>s,
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]1742chained in double-linked lists of siblings and with a children&lt;-&gt;parent
Daniel Veillard306be992000-07-03 12:38:45 +0000[diff] [blame]1743relationship. An xmlNode can also carry properties (a chain of xmlAttr
1744structures). An attribute may have a value which is a list of TEXT or
1745ENTITY_REF nodes.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1746
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1747<p>Here is an example (erroneous with respect to the XML spec since there
1748should be only one ELEMENT under the root):</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1749
1750<p><img src="structure.gif" alt=" structure.gif "></p>
1751
1752<p>In the source package there is a small program (not installed by default)
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]1753called <strong>xmllint</strong> which parses XML files given as argument and
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1754prints them back as parsed. This is useful for detecting errors both in XML
1755code and in the XML parser itself. It has an option <strong>--debug</strong>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]1756which prints the actual in-memory structure of the document; here is the
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1757result with the <a href="#example">example</a> given before:</p>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]1758<pre>DOCUMENT
1759version=1.0
1760standalone=true
1761 ELEMENT EXAMPLE
1762 ATTRIBUTE prop1
1763 TEXT
1764 content=gnome is great
1765 ATTRIBUTE prop2
1766 ENTITY_REF
1767 TEXT
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]1768 content= linux too
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]1769 ELEMENT head
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]1770 ELEMENT title
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]1771 TEXT
1772 content=Welcome to Gnome
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]1773 ELEMENT chapter
1774 ELEMENT title
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]1775 TEXT
1776 content=The Linux adventure
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]1777 ELEMENT p
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]1778 TEXT
1779 content=bla bla bla ...
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]1780 ELEMENT image
1781 ATTRIBUTE href
1782 TEXT
1783 content=linus.gif
1784 ELEMENT p
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]1785 TEXT
1786 content=...</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1787
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1788<p>This should be useful for learning the internal representation model.</p>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]1789
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]1790<h2><a name="interface">The SAX interface</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1791
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]1792<p>Sometimes the DOM tree output is just too large to fit reasonably into
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1793memory. In that case (and if you don't expect to save back the XML document
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]1794loaded using libxml), it's better to use the SAX interface of libxml. SAX is
1795a <strong>callback-based interface</strong> to the parser. Before parsing,
1796the application layer registers a customized set of callbacks which are
1797called by the library as it progresses through the XML input.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1798
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1799<p>To get more detailed step-by-step guidance on using the SAX interface of
Daniel Veillard4540be42000-08-19 16:40:28 +0000[diff] [blame]1800libxml, see the <a
1801href="http://www.daa.com.au/~james/gnome/xml-sax/xml-sax.html">nice
1802documentation</a>.written by <a href="mailto:james@daa.com.au">James
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1803Henstridge</a>.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1804
1805<p>You can debug the SAX behaviour by using the <strong>testSAX</strong>
1806program located in the gnome-xml module (it's usually not shipped in the
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1807binary packages of libxml, but you can find it in the tar source
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]1808distribution). Here is the sequence of callbacks that would be reported by
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1809testSAX when parsing the example XML document shown earlier:</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1810<pre>SAX.setDocumentLocator()
1811SAX.startDocument()
1812SAX.getEntity(amp)
1813SAX.startElement(EXAMPLE, prop1='gnome is great', prop2='&amp;amp; linux too')
1814SAX.characters( , 3)
1815SAX.startElement(head)
1816SAX.characters( , 4)
1817SAX.startElement(title)
1818SAX.characters(Welcome to Gnome, 16)
1819SAX.endElement(title)
1820SAX.characters( , 3)
1821SAX.endElement(head)
1822SAX.characters( , 3)
1823SAX.startElement(chapter)
1824SAX.characters( , 4)
1825SAX.startElement(title)
1826SAX.characters(The Linux adventure, 19)
1827SAX.endElement(title)
1828SAX.characters( , 4)
1829SAX.startElement(p)
1830SAX.characters(bla bla bla ..., 15)
1831SAX.endElement(p)
1832SAX.characters( , 4)
1833SAX.startElement(image, href='linus.gif')
1834SAX.endElement(image)
1835SAX.characters( , 4)
1836SAX.startElement(p)
1837SAX.characters(..., 3)
1838SAX.endElement(p)
1839SAX.characters( , 3)
1840SAX.endElement(chapter)
1841SAX.characters( , 1)
1842SAX.endElement(EXAMPLE)
1843SAX.endDocument()</pre>
1844
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]1845<p>Most of the other interfaces of libxml are based on the DOM tree-building
1846facility, so nearly everything up to the end of this document presupposes the
1847use of the standard DOM tree build. Note that the DOM tree itself is built by
1848a set of registered default callbacks, without internal specific
1849interface.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1850
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]1851<h2><a name="Validation">Validation &amp; DTDs</a></h2>
1852
1853<p>Table of Content:</p>
1854<ol>
1855 <li><a href="#General5">General overview</a></li>
1856 <li><a href="#definition">The definition</a></li>
1857 <li><a href="#Simple">Simple rules</a>
1858 <ol>
Daniel Veillard9c466822001-10-25 12:03:39 +0000[diff] [blame]1859 <li><a href="#reference">How to reference a DTD from a document</a></li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]1860 <li><a href="#Declaring">Declaring elements</a></li>
1861 <li><a href="#Declaring1">Declaring attributes</a></li>
1862 </ol>
1863 </li>
1864 <li><a href="#Some">Some examples</a></li>
1865 <li><a href="#validate">How to validate</a></li>
1866 <li><a href="#Other">Other resources</a></li>
1867</ol>
1868
1869<h3><a name="General5">General overview</a></h3>
1870
1871<p>Well what is validation and what is a DTD ?</p>
1872
1873<p>DTD is the acronym for Document Type Definition. This is a description of
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1874the content for a family of XML files. This is part of the XML 1.0
Daniel Veillardc0801af2002-05-28 16:28:42 +0000[diff] [blame]1875specification, and allows to describe and check that a given document
1876instance conforms to a set of rules detailing its structure and content.</p>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]1877
1878<p>Validation is the process of checking a document against a DTD (more
1879generally against a set of construction rules).</p>
1880
1881<p>The validation process and building DTDs are the two most difficult parts
1882of the XML life cycle. Briefly a DTD defines all the possibles element to be
1883found within your document, what is the formal shape of your document tree
1884(by defining the allowed content of an element, either text, a regular
1885expression for the allowed list of children, or mixed content i.e. both text
1886and children). The DTD also defines the allowed attributes for all elements
1887and the types of the attributes.</p>
1888
1889<h3><a name="definition1">The definition</a></h3>
1890
1891<p>The <a href="http://www.w3.org/TR/REC-xml">W3C XML Recommendation</a> (<a
1892href="http://www.xml.com/axml/axml.html">Tim Bray's annotated version of
1893Rev1</a>):</p>
1894<ul>
1895 <li><a href="http://www.w3.org/TR/REC-xml#elemdecls">Declaring
1896 elements</a></li>
1897 <li><a href="http://www.w3.org/TR/REC-xml#attdecls">Declaring
1898 attributes</a></li>
1899</ul>
1900
1901<p>(unfortunately) all this is inherited from the SGML world, the syntax is
1902ancient...</p>
1903
1904<h3><a name="Simple1">Simple rules</a></h3>
1905
1906<p>Writing DTD can be done in multiple ways, the rules to build them if you
1907need something fixed or something which can evolve over time can be radically
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1908different. Really complex DTD like DocBook ones are flexible but quite harder
1909to design. I will just focus on DTDs for a formats with a fixed simple
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]1910structure. It is just a set of basic rules, and definitely not exhaustive nor
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1911usable for complex DTD design.</p>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]1912
1913<h4><a name="reference1">How to reference a DTD from a document</a>:</h4>
1914
1915<p>Assuming the top element of the document is <code>spec</code> and the dtd
1916is placed in the file <code>mydtd</code> in the subdirectory
1917<code>dtds</code> of the directory from where the document were loaded:</p>
1918
1919<p><code>&lt;!DOCTYPE spec SYSTEM "dtds/mydtd"&gt;</code></p>
1920
1921<p>Notes:</p>
1922<ul>
1923 <li>the system string is actually an URI-Reference (as defined in <a
1924 href="http://www.ietf.org/rfc/rfc2396.txt">RFC 2396</a>) so you can use a
1925 full URL string indicating the location of your DTD on the Web, this is a
1926 really good thing to do if you want others to validate your document</li>
1927 <li>it is also possible to associate a <code>PUBLIC</code> identifier (a
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1928 magic string) so that the DTD is looked up in catalogs on the client side
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]1929 without having to locate it on the web</li>
1930 <li>a dtd contains a set of elements and attributes declarations, but they
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1931 don't define what the root of the document should be. This is explicitly
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]1932 told to the parser/validator as the first element of the
1933 <code>DOCTYPE</code> declaration.</li>
1934</ul>
1935
1936<h4><a name="Declaring2">Declaring elements</a>:</h4>
1937
1938<p>The following declares an element <code>spec</code>:</p>
1939
1940<p><code>&lt;!ELEMENT spec (front, body, back?)&gt;</code></p>
1941
1942<p>it also expresses that the spec element contains one <code>front</code>,
Daniel Veillardc0801af2002-05-28 16:28:42 +0000[diff] [blame]1943one <code>body</code> and one optional <code>back</code> children elements in
1944this order. The declaration of one element of the structure and its content
1945are done in a single declaration. Similarly the following declares
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]1946<code>div1</code> elements:</p>
1947
Daniel Veillard51737272002-01-23 23:10:38 +0000[diff] [blame]1948<p><code>&lt;!ELEMENT div1 (head, (p | list | note)*, div2?)&gt;</code></p>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]1949
1950<p>means div1 contains one <code>head</code> then a series of optional
1951<code>p</code>, <code>list</code>s and <code>note</code>s and then an
1952optional <code>div2</code>. And last but not least an element can contain
1953text:</p>
1954
1955<p><code>&lt;!ELEMENT b (#PCDATA)&gt;</code></p>
1956
1957<p><code>b</code> contains text or being of mixed content (text and elements
1958in no particular order):</p>
1959
1960<p><code>&lt;!ELEMENT p (#PCDATA|a|ul|b|i|em)*&gt;</code></p>
1961
1962<p><code>p </code>can contain text or <code>a</code>, <code>ul</code>,
1963<code>b</code>, <code>i </code>or <code>em</code> elements in no particular
1964order.</p>
1965
1966<h4><a name="Declaring1">Declaring attributes</a>:</h4>
1967
1968<p>again the attributes declaration includes their content definition:</p>
1969
1970<p><code>&lt;!ATTLIST termdef name CDATA #IMPLIED&gt;</code></p>
1971
1972<p>means that the element <code>termdef</code> can have a <code>name</code>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1973attribute containing text (<code>CDATA</code>) and which is optional
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]1974(<code>#IMPLIED</code>). The attribute value can also be defined within a
1975set:</p>
1976
1977<p><code>&lt;!ATTLIST list type (bullets|ordered|glossary)
1978"ordered"&gt;</code></p>
1979
1980<p>means <code>list</code> element have a <code>type</code> attribute with 3
1981allowed values "bullets", "ordered" or "glossary" and which default to
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1982"ordered" if the attribute is not explicitly specified.</p>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]1983
1984<p>The content type of an attribute can be text (<code>CDATA</code>),
1985anchor/reference/references
1986(<code>ID</code>/<code>IDREF</code>/<code>IDREFS</code>), entity(ies)
1987(<code>ENTITY</code>/<code>ENTITIES</code>) or name(s)
1988(<code>NMTOKEN</code>/<code>NMTOKENS</code>). The following defines that a
1989<code>chapter</code> element can have an optional <code>id</code> attribute
1990of type <code>ID</code>, usable for reference from attribute of type
1991IDREF:</p>
1992
1993<p><code>&lt;!ATTLIST chapter id ID #IMPLIED&gt;</code></p>
1994
1995<p>The last value of an attribute definition can be <code>#REQUIRED
1996</code>meaning that the attribute has to be given, <code>#IMPLIED</code>
1997meaning that it is optional, or the default value (possibly prefixed by
1998<code>#FIXED</code> if it is the only allowed).</p>
1999
2000<p>Notes:</p>
2001<ul>
2002 <li>usually the attributes pertaining to a given element are declared in a
2003 single expression, but it is just a convention adopted by a lot of DTD
2004 writers:
2005 <pre>&lt;!ATTLIST termdef
2006 id ID #REQUIRED
2007 name CDATA #IMPLIED&gt;</pre>
2008 <p>The previous construct defines both <code>id</code> and
2009 <code>name</code> attributes for the element <code>termdef</code></p>
2010 </li>
2011</ul>
2012
2013<h3><a name="Some1">Some examples</a></h3>
2014
2015<p>The directory <code>test/valid/dtds/</code> in the libxml distribution
2016contains some complex DTD examples. The <code>test/valid/dia.xml</code>
2017example shows an XML file where the simple DTD is directly included within
2018the document.</p>
2019
2020<h3><a name="validate1">How to validate</a></h3>
2021
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]2022<p>The simplest is to use the xmllint program coming with libxml. The
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2023<code>--valid</code> option turn on validation of the files given as input,
2024for example the following validates a copy of the first revision of the XML
20251.0 specification:</p>
2026
2027<p><code>xmllint --valid --noout test/valid/REC-xml-19980210.xml</code></p>
2028
2029<p>the -- noout is used to not output the resulting tree.</p>
2030
2031<p>The <code>--dtdvalid dtd</code> allows to validate the document(s) against
2032a given DTD.</p>
2033
2034<p>Libxml exports an API to handle DTDs and validation, check the <a
2035href="http://xmlsoft.org/html/libxml-valid.html">associated
2036description</a>.</p>
2037
2038<h3><a name="Other1">Other resources</a></h3>
2039
2040<p>DTDs are as old as SGML. So there may be a number of examples on-line, I
2041will just list one for now, others pointers welcome:</p>
2042<ul>
2043 <li><a href="http://www.xml101.com:8081/dtd/">XML-101 DTD</a></li>
2044</ul>
2045
2046<p>I suggest looking at the examples found under test/valid/dtd and any of
2047the large number of books available on XML. The dia example in test/valid
2048should be both simple and complete enough to allow you to build your own.</p>
2049
2050<p></p>
2051
2052<h2><a name="Memory">Memory Management</a></h2>
2053
2054<p>Table of Content:</p>
2055<ol>
2056 <li><a href="#General3">General overview</a></li>
Daniel Veillard9c466822001-10-25 12:03:39 +0000[diff] [blame]2057 <li><a href="#setting">Setting libxml set of memory routines</a></li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2058 <li><a href="#cleanup">Cleaning up after parsing</a></li>
2059 <li><a href="#Debugging">Debugging routines</a></li>
2060 <li><a href="#General4">General memory requirements</a></li>
2061</ol>
2062
2063<h3><a name="General3">General overview</a></h3>
2064
2065<p>The module <code><a
2066href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlmemory.h</a></code>
2067provides the interfaces to the libxml memory system:</p>
2068<ul>
2069 <li>libxml does not use the libc memory allocator directly but xmlFree(),
2070 xmlMalloc() and xmlRealloc()</li>
2071 <li>those routines can be reallocated to a specific set of routine, by
2072 default the libc ones i.e. free(), malloc() and realloc()</li>
2073 <li>the xmlmemory.c module includes a set of debugging routine</li>
2074</ul>
2075
2076<h3><a name="setting">Setting libxml set of memory routines</a></h3>
2077
2078<p>It is sometimes useful to not use the default memory allocator, either for
2079debugging, analysis or to implement a specific behaviour on memory management
2080(like on embedded systems). Two function calls are available to do so:</p>
2081<ul>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]2082 <li><a href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlMemGet
2083 ()</a> which return the current set of functions in use by the parser</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2084 <li><a
2085 href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlMemSetup()</a>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]2086 which allow to set up a new set of memory allocation functions</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2087</ul>
2088
2089<p>Of course a call to xmlMemSetup() should probably be done before calling
2090any other libxml routines (unless you are sure your allocations routines are
2091compatibles).</p>
2092
2093<h3><a name="cleanup">Cleaning up after parsing</a></h3>
2094
2095<p>Libxml is not stateless, there is a few set of memory structures needing
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]2096allocation before the parser is fully functional (some encoding structures
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2097for example). This also mean that once parsing is finished there is a tiny
2098amount of memory (a few hundred bytes) which can be recollected if you don't
2099reuse the parser immediately:</p>
2100<ul>
2101 <li><a href="http://xmlsoft.org/html/libxml-parser.html">xmlCleanupParser
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]2102 ()</a> is a centralized routine to free the parsing states. Note that it
2103 won't deallocate any produced tree if any (use the xmlFreeDoc() and
2104 related routines for this).</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2105 <li><a href="http://xmlsoft.org/html/libxml-parser.html">xmlInitParser
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]2106 ()</a> is the dual routine allowing to preallocate the parsing state
2107 which can be useful for example to avoid initialization reentrancy
2108 problems when using libxml in multithreaded applications</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2109</ul>
2110
2111<p>Generally xmlCleanupParser() is safe, if needed the state will be rebuild
2112at the next invocation of parser routines, but be careful of the consequences
2113in multithreaded applications.</p>
2114
2115<h3><a name="Debugging">Debugging routines</a></h3>
2116
2117<p>When configured using --with-mem-debug flag (off by default), libxml uses
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]2118a set of memory allocation debugging routines keeping track of all allocated
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2119blocks and the location in the code where the routine was called. A couple of
2120other debugging routines allow to dump the memory allocated infos to a file
2121or call a specific routine when a given block number is allocated:</p>
2122<ul>
2123 <li><a
2124 href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlMallocLoc()</a>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]2125 <a
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2126 href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlReallocLoc()</a>
2127 and <a
2128 href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlMemStrdupLoc()</a>
2129 are the memory debugging replacement allocation routines</li>
2130 <li><a href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlMemoryDump
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]2131 ()</a> dumps all the informations about the allocated memory block lefts
2132 in the <code>.memdump</code> file</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2133</ul>
2134
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]2135<p>When developing libxml memory debug is enabled, the tests programs call
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2136xmlMemoryDump () and the "make test" regression tests will check for any
2137memory leak during the full regression test sequence, this helps a lot
2138ensuring that libxml does not leak memory and bullet proof memory
2139allocations use (some libc implementations are known to be far too permissive
2140resulting in major portability problems!).</p>
2141
2142<p>If the .memdump reports a leak, it displays the allocation function and
2143also tries to give some informations about the content and structure of the
2144allocated blocks left. This is sufficient in most cases to find the culprit,
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]2145but not always. Assuming the allocation problem is reproducible, it is
2146possible to find more easily:</p>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2147<ol>
2148 <li>write down the block number xxxx not allocated</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]2149 <li>export the environment variable XML_MEM_BREAKPOINT=xxxx , the easiest
Daniel Veillard75794822002-04-11 16:24:32 +0000[diff] [blame]2150 when using GDB is to simply give the command
2151 <p><code>set environment XML_MEM_BREAKPOINT xxxx</code></p>
2152 <p>before running the program.</p>
2153 </li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2154 <li>run the program under a debugger and set a breakpoint on
2155 xmlMallocBreakpoint() a specific function called when this precise block
2156 is allocated</li>
2157 <li>when the breakpoint is reached you can then do a fine analysis of the
2158 allocation an step to see the condition resulting in the missing
2159 deallocation.</li>
2160</ol>
2161
2162<p>I used to use a commercial tool to debug libxml memory problems but after
2163noticing that it was not detecting memory leaks that simple mechanism was
Daniel Veillard75794822002-04-11 16:24:32 +0000[diff] [blame]2164used and proved extremely efficient until now. Lately I have also used <a
2165href="http://developer.kde.org/~sewardj/">valgrind</a> with quite some
2166success, it is tied to the i386 architecture since it works by emulating the
2167processor and instruction set, it is slow but extremely efficient, i.e. it
2168spot memory usage errors in a very precise way.</p>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2169
2170<h3><a name="General4">General memory requirements</a></h3>
2171
2172<p>How much libxml memory require ? It's hard to tell in average it depends
2173of a number of things:</p>
2174<ul>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]2175 <li>the parser itself should work in a fixed amount of memory, except for
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2176 information maintained about the stacks of names and entities locations.
2177 The I/O and encoding handlers will probably account for a few KBytes.
2178 This is true for both the XML and HTML parser (though the HTML parser
2179 need more state).</li>
2180 <li>If you are generating the DOM tree then memory requirements will grow
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]2181 nearly linear with the size of the data. In general for a balanced
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2182 textual document the internal memory requirement is about 4 times the
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]2183 size of the UTF8 serialization of this document (example the XML-1.0
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2184 recommendation is a bit more of 150KBytes and takes 650KBytes of main
2185 memory when parsed). Validation will add a amount of memory required for
2186 maintaining the external Dtd state which should be linear with the
2187 complexity of the content model defined by the Dtd</li>
2188 <li>If you don't care about the advanced features of libxml like
2189 validation, DOM, XPath or XPointer, but really need to work fixed memory
2190 requirements, then the SAX interface should be used.</li>
2191</ul>
2192
2193<p></p>
2194
2195<h2><a name="Encodings">Encodings support</a></h2>
2196
2197<p>Table of Content:</p>
2198<ol>
2199 <li><a href="encoding.html#What">What does internationalization support
2200 mean ?</a></li>
2201 <li><a href="encoding.html#internal">The internal encoding, how and
2202 why</a></li>
2203 <li><a href="encoding.html#implemente">How is it implemented ?</a></li>
2204 <li><a href="encoding.html#Default">Default supported encodings</a></li>
2205 <li><a href="encoding.html#extend">How to extend the existing
2206 support</a></li>
2207</ol>
2208
2209<h3><a name="What">What does internationalization support mean ?</a></h3>
2210
2211<p>XML was designed from the start to allow the support of any character set
2212by using Unicode. Any conformant XML parser has to support the UTF-8 and
2213UTF-16 default encodings which can both express the full unicode ranges. UTF8
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]2214is a variable length encoding whose greatest points are to reuse the same
2215encoding for ASCII and to save space for Western encodings, but it is a bit
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2216more complex to handle in practice. UTF-16 use 2 bytes per characters (and
2217sometimes combines two pairs), it makes implementation easier, but looks a
2218bit overkill for Western languages encoding. Moreover the XML specification
2219allows document to be encoded in other encodings at the condition that they
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]2220are clearly labeled as such. For example the following is a wellformed XML
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2221document encoded in ISO-8859 1 and using accentuated letter that we French
2222likes for both markup and content:</p>
2223<pre>&lt;?xml version="1.0" encoding="ISO-8859-1"?&gt;
2224&lt;très&gt;là&lt;/très&gt;</pre>
2225
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]2226<p>Having internationalization support in libxml means the following:</p>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2227<ul>
2228 <li>the document is properly parsed</li>
2229 <li>informations about it's encoding are saved</li>
2230 <li>it can be modified</li>
2231 <li>it can be saved in its original encoding</li>
2232 <li>it can also be saved in another encoding supported by libxml (for
2233 example straight UTF8 or even an ASCII form)</li>
2234</ul>
2235
2236<p>Another very important point is that the whole libxml API, with the
2237exception of a few routines to read with a specific encoding or save to a
2238specific encoding, is completely agnostic about the original encoding of the
2239document.</p>
2240
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]2241<p>It should be noted too that the HTML parser embedded in libxml now obey
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2242the same rules too, the following document will be (as of 2.2.2) handled in
2243an internationalized fashion by libxml too:</p>
2244<pre>&lt;!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"
2245 "http://www.w3.org/TR/REC-html40/loose.dtd"&gt;
2246&lt;html lang="fr"&gt;
2247&lt;head&gt;
2248 &lt;META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=ISO-8859-1"&gt;
2249&lt;/head&gt;
2250&lt;body&gt;
2251&lt;p&gt;W3C crée des standards pour le Web.&lt;/body&gt;
2252&lt;/html&gt;</pre>
2253
2254<h3><a name="internal">The internal encoding, how and why</a></h3>
2255
2256<p>One of the core decision was to force all documents to be converted to a
2257default internal encoding, and that encoding to be UTF-8, here are the
2258rationale for those choices:</p>
2259<ul>
2260 <li>keeping the native encoding in the internal form would force the libxml
2261 users (or the code associated) to be fully aware of the encoding of the
2262 original document, for examples when adding a text node to a document,
2263 the content would have to be provided in the document encoding, i.e. the
2264 client code would have to check it before hand, make sure it's conformant
2265 to the encoding, etc ... Very hard in practice, though in some specific
2266 cases this may make sense.</li>
2267 <li>the second decision was which encoding. From the XML spec only UTF8 and
2268 UTF16 really makes sense as being the two only encodings for which there
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]2269 is mandatory support. UCS-4 (32 bits fixed size encoding) could be
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2270 considered an intelligent choice too since it's a direct Unicode mapping
2271 support. I selected UTF-8 on the basis of efficiency and compatibility
2272 with surrounding software:
2273 <ul>
2274 <li>UTF-8 while a bit more complex to convert from/to (i.e. slightly
2275 more costly to import and export CPU wise) is also far more compact
2276 than UTF-16 (and UCS-4) for a majority of the documents I see it used
2277 for right now (RPM RDF catalogs, advogato data, various configuration
2278 file formats, etc.) and the key point for today's computer
2279 architecture is efficient uses of caches. If one nearly double the
2280 memory requirement to store the same amount of data, this will trash
2281 caches (main memory/external caches/internal caches) and my take is
2282 that this harms the system far more than the CPU requirements needed
2283 for the conversion to UTF-8</li>
2284 <li>Most of libxml version 1 users were using it with straight ASCII
2285 most of the time, doing the conversion with an internal encoding
2286 requiring all their code to be rewritten was a serious show-stopper
2287 for using UTF-16 or UCS-4.</li>
2288 <li>UTF-8 is being used as the de-facto internal encoding standard for
2289 related code like the <a href="http://www.pango.org/">pango</a>
2290 upcoming Gnome text widget, and a lot of Unix code (yep another place
2291 where Unix programmer base takes a different approach from Microsoft
2292 - they are using UTF-16)</li>
2293 </ul>
2294 </li>
2295</ul>
2296
2297<p>What does this mean in practice for the libxml user:</p>
2298<ul>
2299 <li>xmlChar, the libxml data type is a byte, those bytes must be assembled
2300 as UTF-8 valid strings. The proper way to terminate an xmlChar * string
2301 is simply to append 0 byte, as usual.</li>
2302 <li>One just need to make sure that when using chars outside the ASCII set,
2303 the values has been properly converted to UTF-8</li>
2304</ul>
2305
2306<h3><a name="implemente">How is it implemented ?</a></h3>
2307
2308<p>Let's describe how all this works within libxml, basically the I18N
2309(internationalization) support get triggered only during I/O operation, i.e.
2310when reading a document or saving one. Let's look first at the reading
2311sequence:</p>
2312<ol>
2313 <li>when a document is processed, we usually don't know the encoding, a
2314 simple heuristic allows to detect UTF-18 and UCS-4 from whose where the
2315 ASCII range (0-0x7F) maps with ASCII</li>
2316 <li>the xml declaration if available is parsed, including the encoding
2317 declaration. At that point, if the autodetected encoding is different
2318 from the one declared a call to xmlSwitchEncoding() is issued.</li>
2319 <li>If there is no encoding declaration, then the input has to be in either
2320 UTF-8 or UTF-16, if it is not then at some point when processing the
2321 input, the converter/checker of UTF-8 form will raise an encoding error.
2322 You may end-up with a garbled document, or no document at all ! Example:
2323 <pre>~/XML -&gt; ./xmllint err.xml
2324err.xml:1: error: Input is not proper UTF-8, indicate encoding !
2325&lt;très&gt;là&lt;/très&gt;
2326 ^
2327err.xml:1: error: Bytes: 0xE8 0x73 0x3E 0x6C
2328&lt;très&gt;là&lt;/très&gt;
2329 ^</pre>
2330 </li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]2331 <li>xmlSwitchEncoding() does an encoding name lookup, canonicalize it, and
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2332 then search the default registered encoding converters for that encoding.
2333 If it's not within the default set and iconv() support has been compiled
2334 it, it will ask iconv for such an encoder. If this fails then the parser
2335 will report an error and stops processing:
2336 <pre>~/XML -&gt; ./xmllint err2.xml
2337err2.xml:1: error: Unsupported encoding UnsupportedEnc
2338&lt;?xml version="1.0" encoding="UnsupportedEnc"?&gt;
2339 ^</pre>
2340 </li>
Daniel Veillard46c5c1d2002-05-20 07:15:54 +0000[diff] [blame]2341 <li>From that point the encoder processes progressively the input (it is
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2342 plugged as a front-end to the I/O module) for that entity. It captures
2343 and convert on-the-fly the document to be parsed to UTF-8. The parser
2344 itself just does UTF-8 checking of this input and process it
2345 transparently. The only difference is that the encoding information has
2346 been added to the parsing context (more precisely to the input
2347 corresponding to this entity).</li>
2348 <li>The result (when using DOM) is an internal form completely in UTF-8
2349 with just an encoding information on the document node.</li>
2350</ol>
2351
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]2352<p>Ok then what happens when saving the document (assuming you
2353collected/built an xmlDoc DOM like structure) ? It depends on the function
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2354called, xmlSaveFile() will just try to save in the original encoding, while
2355xmlSaveFileTo() and xmlSaveFileEnc() can optionally save to a given
2356encoding:</p>
2357<ol>
2358 <li>if no encoding is given, libxml will look for an encoding value
2359 associated to the document and if it exists will try to save to that
2360 encoding,
2361 <p>otherwise everything is written in the internal form, i.e. UTF-8</p>
2362 </li>
2363 <li>so if an encoding was specified, either at the API level or on the
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]2364 document, libxml will again canonicalize the encoding name, lookup for a
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2365 converter in the registered set or through iconv. If not found the
2366 function will return an error code</li>
2367 <li>the converter is placed before the I/O buffer layer, as another kind of
2368 buffer, then libxml will simply push the UTF-8 serialization to through
2369 that buffer, which will then progressively be converted and pushed onto
2370 the I/O layer.</li>
2371 <li>It is possible that the converter code fails on some input, for example
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]2372 trying to push an UTF-8 encoded Chinese character through the UTF-8 to
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2373 ISO-8859-1 converter won't work. Since the encoders are progressive they
2374 will just report the error and the number of bytes converted, at that
2375 point libxml will decode the offending character, remove it from the
2376 buffer and replace it with the associated charRef encoding &amp;#123; and
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]2377 resume the conversion. This guarantees that any document will be saved
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2378 without losses (except for markup names where this is not legal, this is
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]2379 a problem in the current version, in practice avoid using non-ascii
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2380 characters for tags or attributes names @@). A special "ascii" encoding
2381 name is used to save documents to a pure ascii form can be used when
2382 portability is really crucial</li>
2383</ol>
2384
2385<p>Here is a few examples based on the same test document:</p>
2386<pre>~/XML -&gt; ./xmllint isolat1
2387&lt;?xml version="1.0" encoding="ISO-8859-1"?&gt;
2388&lt;très&gt;là&lt;/très&gt;
2389~/XML -&gt; ./xmllint --encode UTF-8 isolat1
2390&lt;?xml version="1.0" encoding="UTF-8"?&gt;
2391&lt;très&gt;là  &lt;/très&gt;
2392~/XML -&gt; </pre>
2393
2394<p>The same processing is applied (and reuse most of the code) for HTML I18N
2395processing. Looking up and modifying the content encoding is a bit more
2396difficult since it is located in a &lt;meta&gt; tag under the &lt;head&gt;,
2397so a couple of functions htmlGetMetaEncoding() and htmlSetMetaEncoding() have
2398been provided. The parser also attempts to switch encoding on the fly when
2399detecting such a tag on input. Except for that the processing is the same
2400(and again reuses the same code).</p>
2401
2402<h3><a name="Default">Default supported encodings</a></h3>
2403
2404<p>libxml has a set of default converters for the following encodings
2405(located in encoding.c):</p>
2406<ol>
2407 <li>UTF-8 is supported by default (null handlers)</li>
2408 <li>UTF-16, both little and big endian</li>
2409 <li>ISO-Latin-1 (ISO-8859-1) covering most western languages</li>
2410 <li>ASCII, useful mostly for saving</li>
2411 <li>HTML, a specific handler for the conversion of UTF-8 to ASCII with HTML
2412 predefined entities like &amp;copy; for the Copyright sign.</li>
2413</ol>
2414
Daniel Veillardc0801af2002-05-28 16:28:42 +0000[diff] [blame]2415<p>More over when compiled on an Unix platform with iconv support the full
2416set of encodings supported by iconv can be instantly be used by libxml. On a
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2417linux machine with glibc-2.1 the list of supported encodings and aliases fill
24183 full pages, and include UCS-4, the full set of ISO-Latin encodings, and the
2419various Japanese ones.</p>
2420
2421<h4>Encoding aliases</h4>
2422
2423<p>From 2.2.3, libxml has support to register encoding names aliases. The
2424goal is to be able to parse document whose encoding is supported but where
2425the name differs (for example from the default set of names accepted by
2426iconv). The following functions allow to register and handle new aliases for
2427existing encodings. Once registered libxml will automatically lookup the
2428aliases when handling a document:</p>
2429<ul>
2430 <li>int xmlAddEncodingAlias(const char *name, const char *alias);</li>
2431 <li>int xmlDelEncodingAlias(const char *alias);</li>
2432 <li>const char * xmlGetEncodingAlias(const char *alias);</li>
2433 <li>void xmlCleanupEncodingAliases(void);</li>
2434</ul>
2435
2436<h3><a name="extend">How to extend the existing support</a></h3>
2437
2438<p>Well adding support for new encoding, or overriding one of the encoders
2439(assuming it is buggy) should not be hard, just write an input and output
2440conversion routines to/from UTF-8, and register them using
2441xmlNewCharEncodingHandler(name, xxxToUTF8, UTF8Toxxx), and they will be
2442called automatically if the parser(s) encounter such an encoding name
2443(register it uppercase, this will help). The description of the encoders,
2444their arguments and expected return values are described in the encoding.h
2445header.</p>
2446
2447<p>A quick note on the topic of subverting the parser to use a different
2448internal encoding than UTF-8, in some case people will absolutely want to
2449keep the internal encoding different, I think it's still possible (but the
2450encoding must be compliant with ASCII on the same subrange) though I didn't
2451tried it. The key is to override the default conversion routines (by
2452registering null encoders/decoders for your charsets), and bypass the UTF-8
2453checking of the parser by setting the parser context charset
2454(ctxt-&gt;charset) to something different than XML_CHAR_ENCODING_UTF8, but
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]2455there is no guarantee that this will work. You may also have some troubles
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2456saving back.</p>
2457
2458<p>Basically proper I18N support is important, this requires at least
2459libxml-2.0.0, but a lot of features and corrections are really available only
2460starting 2.2.</p>
2461
2462<h2><a name="IO">I/O Interfaces</a></h2>
2463
2464<p>Table of Content:</p>
2465<ol>
2466 <li><a href="#General1">General overview</a></li>
2467 <li><a href="#basic">The basic buffer type</a></li>
2468 <li><a href="#Input">Input I/O handlers</a></li>
2469 <li><a href="#Output">Output I/O handlers</a></li>
2470 <li><a href="#entities">The entities loader</a></li>
2471 <li><a href="#Example2">Example of customized I/O</a></li>
2472</ol>
2473
2474<h3><a name="General1">General overview</a></h3>
2475
2476<p>The module <code><a
2477href="http://xmlsoft.org/html/libxml-xmlio.html">xmlIO.h</a></code> provides
2478the interfaces to the libxml I/O system. This consists of 4 main parts:</p>
2479<ul>
2480 <li>Entities loader, this is a routine which tries to fetch the entities
2481 (files) based on their PUBLIC and SYSTEM identifiers. The default loader
2482 don't look at the public identifier since libxml do not maintain a
2483 catalog. You can redefine you own entity loader by using
2484 <code>xmlGetExternalEntityLoader()</code> and
Daniel Veillard9c466822001-10-25 12:03:39 +0000[diff] [blame]2485 <code>xmlSetExternalEntityLoader()</code>. <a href="#entities">Check the
2486 example</a>.</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2487 <li>Input I/O buffers which are a commodity structure used by the parser(s)
2488 input layer to handle fetching the informations to feed the parser. This
2489 provides buffering and is also a placeholder where the encoding
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]2490 converters to UTF8 are piggy-backed.</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2491 <li>Output I/O buffers are similar to the Input ones and fulfill similar
2492 task but when generating a serialization from a tree.</li>
2493 <li>A mechanism to register sets of I/O callbacks and associate them with
2494 specific naming schemes like the protocol part of the URIs.
2495 <p>This affect the default I/O operations and allows to use specific I/O
2496 handlers for certain names.</p>
2497 </li>
2498</ul>
2499
2500<p>The general mechanism used when loading http://rpmfind.net/xml.html for
2501example in the HTML parser is the following:</p>
2502<ol>
2503 <li>The default entity loader calls <code>xmlNewInputFromFile()</code> with
2504 the parsing context and the URI string.</li>
2505 <li>the URI string is checked against the existing registered handlers
2506 using their match() callback function, if the HTTP module was compiled
2507 in, it is registered and its match() function will succeeds</li>
2508 <li>the open() function of the handler is called and if successful will
2509 return an I/O Input buffer</li>
2510 <li>the parser will the start reading from this buffer and progressively
2511 fetch information from the resource, calling the read() function of the
2512 handler until the resource is exhausted</li>
2513 <li>if an encoding change is detected it will be installed on the input
2514 buffer, providing buffering and efficient use of the conversion
2515 routines</li>
2516 <li>once the parser has finished, the close() function of the handler is
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]2517 called once and the Input buffer and associated resources are
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2518 deallocated.</li>
2519</ol>
2520
2521<p>The user defined callbacks are checked first to allow overriding of the
2522default libxml I/O routines.</p>
2523
2524<h3><a name="basic">The basic buffer type</a></h3>
2525
2526<p>All the buffer manipulation handling is done using the
2527<code>xmlBuffer</code> type define in <code><a
2528href="http://xmlsoft.org/html/libxml-tree.html">tree.h</a> </code>which is a
2529resizable memory buffer. The buffer allocation strategy can be selected to be
2530either best-fit or use an exponential doubling one (CPU vs. memory use
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]2531trade-off). The values are <code>XML_BUFFER_ALLOC_EXACT</code> and
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2532<code>XML_BUFFER_ALLOC_DOUBLEIT</code>, and can be set individually or on a
2533system wide basis using <code>xmlBufferSetAllocationScheme()</code>. A number
2534of functions allows to manipulate buffers with names starting with the
2535<code>xmlBuffer...</code> prefix.</p>
2536
2537<h3><a name="Input">Input I/O handlers</a></h3>
2538
2539<p>An Input I/O handler is a simple structure
2540<code>xmlParserInputBuffer</code> containing a context associated to the
2541resource (file descriptor, or pointer to a protocol handler), the read() and
2542close() callbacks to use and an xmlBuffer. And extra xmlBuffer and a charset
2543encoding handler are also present to support charset conversion when
2544needed.</p>
2545
2546<h3><a name="Output">Output I/O handlers</a></h3>
2547
2548<p>An Output handler <code>xmlOutputBuffer</code> is completely similar to an
2549Input one except the callbacks are write() and close().</p>
2550
2551<h3><a name="entities">The entities loader</a></h3>
2552
2553<p>The entity loader resolves requests for new entities and create inputs for
2554the parser. Creating an input from a filename or an URI string is done
2555through the xmlNewInputFromFile() routine. The default entity loader do not
2556handle the PUBLIC identifier associated with an entity (if any). So it just
2557calls xmlNewInputFromFile() with the SYSTEM identifier (which is mandatory in
2558XML).</p>
2559
2560<p>If you want to hook up a catalog mechanism then you simply need to
2561override the default entity loader, here is an example:</p>
2562<pre>#include &lt;libxml/xmlIO.h&gt;
2563
2564xmlExternalEntityLoader defaultLoader = NULL;
2565
2566xmlParserInputPtr
2567xmlMyExternalEntityLoader(const char *URL, const char *ID,
2568 xmlParserCtxtPtr ctxt) {
2569 xmlParserInputPtr ret;
2570 const char *fileID = NULL;
2571 /* lookup for the fileID depending on ID */
2572
2573 ret = xmlNewInputFromFile(ctxt, fileID);
2574 if (ret != NULL)
2575 return(ret);
2576 if (defaultLoader != NULL)
2577 ret = defaultLoader(URL, ID, ctxt);
2578 return(ret);
2579}
2580
2581int main(..) {
2582 ...
2583
2584 /*
2585 * Install our own entity loader
2586 */
2587 defaultLoader = xmlGetExternalEntityLoader();
2588 xmlSetExternalEntityLoader(xmlMyExternalEntityLoader);
2589
2590 ...
2591}</pre>
2592
2593<h3><a name="Example2">Example of customized I/O</a></h3>
2594
2595<p>This example come from <a href="http://xmlsoft.org/messages/0708.html">a
2596real use case</a>, xmlDocDump() closes the FILE * passed by the application
2597and this was a problem. The <a
2598href="http://xmlsoft.org/messages/0711.html">solution</a> was to redefine a
2599new output handler with the closing call deactivated:</p>
2600<ol>
Daniel Veillardc0801af2002-05-28 16:28:42 +0000[diff] [blame]2601 <li>First define a new I/O output allocator where the output don't close
2602 the file:
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2603 <pre>xmlOutputBufferPtr
2604xmlOutputBufferCreateOwn(FILE *file, xmlCharEncodingHandlerPtr encoder) {
2605    xmlOutputBufferPtr ret;
2606    
2607    if (xmlOutputCallbackInitialized == 0)
2608        xmlRegisterDefaultOutputCallbacks();
2609
2610    if (file == NULL) return(NULL);
2611    ret = xmlAllocOutputBuffer(encoder);
2612    if (ret != NULL) {
2613        ret-&gt;context = file;
2614        ret-&gt;writecallback = xmlFileWrite;
2615        ret-&gt;closecallback = NULL; /* No close callback */
2616    }
2617    return(ret); <br>
Daniel Veillard1eb24242002-03-18 11:33:03 +0000[diff] [blame]2618
Daniel Veillard34ce8be2002-03-18 19:37:11 +0000[diff] [blame]2619
2620
Daniel Veillard19274092002-03-25 16:48:03 +0000[diff] [blame]2621
Daniel Veillardb2fb8ed2002-04-01 09:33:12 +0000[diff] [blame]2622
Daniel Veillard75794822002-04-11 16:24:32 +0000[diff] [blame]2623
Daniel Veillarda7084cd2002-04-15 17:12:47 +0000[diff] [blame]2624
Daniel Veillard0bfbb422002-04-26 09:21:45 +0000[diff] [blame]2625
Daniel Veillard93d3a472002-04-26 14:04:55 +0000[diff] [blame]2626
Daniel Veillardcf27f7c2002-04-30 07:12:39 +0000[diff] [blame]2627
Daniel Veillarde6d8e202002-05-02 06:11:10 +0000[diff] [blame]2628
Daniel Veillard9b6fd302002-05-13 12:06:47 +0000[diff] [blame]2629
Daniel Veillardc0801af2002-05-28 16:28:42 +0000[diff] [blame]2630
Daniel Veillard21473672002-06-17 07:29:22 +0000[diff] [blame]2631
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2632} </pre>
2633 </li>
2634 <li>And then use it to save the document:
2635 <pre>FILE *f;
2636xmlOutputBufferPtr output;
2637xmlDocPtr doc;
2638int res;
2639
2640f = ...
2641doc = ....
2642
2643output = xmlOutputBufferCreateOwn(f, NULL);
2644res = xmlSaveFileTo(output, doc, NULL);
2645 </pre>
2646 </li>
2647</ol>
2648
2649<h2><a name="Catalog">Catalog support</a></h2>
2650
2651<p>Table of Content:</p>
2652<ol>
2653 <li><a href="General2">General overview</a></li>
2654 <li><a href="#definition">The definition</a></li>
2655 <li><a href="#Simple">Using catalogs</a></li>
2656 <li><a href="#Some">Some examples</a></li>
2657 <li><a href="#reference">How to tune catalog usage</a></li>
2658 <li><a href="#validate">How to debug catalog processing</a></li>
2659 <li><a href="#Declaring">How to create and maintain catalogs</a></li>
2660 <li><a href="#implemento">The implementor corner quick review of the
2661 API</a></li>
2662 <li><a href="#Other">Other resources</a></li>
2663</ol>
2664
2665<h3><a name="General2">General overview</a></h3>
2666
2667<p>What is a catalog? Basically it's a lookup mechanism used when an entity
2668(a file or a remote resource) references another entity. The catalog lookup
2669is inserted between the moment the reference is recognized by the software
2670(XML parser, stylesheet processing, or even images referenced for inclusion
2671in a rendering) and the time where loading that resource is actually
2672started.</p>
2673
2674<p>It is basically used for 3 things:</p>
2675<ul>
2676 <li>mapping from "logical" names, the public identifiers and a more
2677 concrete name usable for download (and URI). For example it can associate
2678 the logical name
2679 <p>"-//OASIS//DTD DocBook XML V4.1.2//EN"</p>
2680 <p>of the DocBook 4.1.2 XML DTD with the actual URL where it can be
2681 downloaded</p>
2682 <p>http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd</p>
2683 </li>
2684 <li>remapping from a given URL to another one, like an HTTP indirection
2685 saying that
2686 <p>"http://www.oasis-open.org/committes/tr.xsl"</p>
2687 <p>should really be looked at</p>
2688 <p>"http://www.oasis-open.org/committes/entity/stylesheets/base/tr.xsl"</p>
2689 </li>
2690 <li>providing a local cache mechanism allowing to load the entities
2691 associated to public identifiers or remote resources, this is a really
2692 important feature for any significant deployment of XML or SGML since it
2693 allows to avoid the aleas and delays associated to fetching remote
2694 resources.</li>
2695</ul>
2696
2697<h3><a name="definition">The definitions</a></h3>
2698
2699<p>Libxml, as of 2.4.3 implements 2 kind of catalogs:</p>
2700<ul>
2701 <li>the older SGML catalogs, the official spec is SGML Open Technical
2702 Resolution TR9401:1997, but is better understood by reading <a
2703 href="http://www.jclark.com/sp/catalog.htm">the SP Catalog page</a> from
2704 James Clark. This is relatively old and not the preferred mode of
2705 operation of libxml.</li>
2706 <li><a href="http://www.oasis-open.org/committees/entity/spec.html">XML
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]2707 Catalogs</a> is far more flexible, more recent, uses an XML syntax and
2708 should scale quite better. This is the default option of libxml.</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2709</ul>
2710
2711<p></p>
2712
2713<h3><a name="Simple">Using catalog</a></h3>
2714
2715<p>In a normal environment libxml will by default check the presence of a
2716catalog in /etc/xml/catalog, and assuming it has been correctly populated,
2717the processing is completely transparent to the document user. To take a
2718concrete example, suppose you are authoring a DocBook document, this one
2719starts with the following DOCTYPE definition:</p>
2720<pre>&lt;?xml version='1.0'?&gt;
2721&lt;!DOCTYPE book PUBLIC "-//Norman Walsh//DTD DocBk XML V3.1.4//EN"
2722 "http://nwalsh.com/docbook/xml/3.1.4/db3xml.dtd"&gt;</pre>
2723
2724<p>When validating the document with libxml, the catalog will be
2725automatically consulted to lookup the public identifier "-//Norman Walsh//DTD
2726DocBk XML V3.1.4//EN" and the system identifier
2727"http://nwalsh.com/docbook/xml/3.1.4/db3xml.dtd", and if these entities have
2728been installed on your system and the catalogs actually point to them, libxml
2729will fetch them from the local disk.</p>
2730
2731<p style="font-size: 10pt"><strong>Note</strong>: Really don't use this
2732DOCTYPE example it's a really old version, but is fine as an example.</p>
2733
2734<p>Libxml will check the catalog each time that it is requested to load an
2735entity, this includes DTD, external parsed entities, stylesheets, etc ... If
2736your system is correctly configured all the authoring phase and processing
2737should use only local files, even if your document stays portable because it
2738uses the canonical public and system ID, referencing the remote document.</p>
2739
2740<h3><a name="Some">Some examples:</a></h3>
2741
2742<p>Here is a couple of fragments from XML Catalogs used in libxml early
2743regression tests in <code>test/catalogs</code> :</p>
2744<pre>&lt;?xml version="1.0"?&gt;
2745&lt;!DOCTYPE catalog PUBLIC
2746 "-//OASIS//DTD Entity Resolution XML Catalog V1.0//EN"
2747 "http://www.oasis-open.org/committees/entity/release/1.0/catalog.dtd"&gt;
2748&lt;catalog xmlns="urn:oasis:names:tc:entity:xmlns:xml:catalog"&gt;
2749 &lt;public publicId="-//OASIS//DTD DocBook XML V4.1.2//EN"
2750 uri="http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd"/&gt;
2751...</pre>
2752
2753<p>This is the beginning of a catalog for DocBook 4.1.2, XML Catalogs are
2754written in XML, there is a specific namespace for catalog elements
2755"urn:oasis:names:tc:entity:xmlns:xml:catalog". The first entry in this
2756catalog is a <code>public</code> mapping it allows to associate a Public
2757Identifier with an URI.</p>
2758<pre>...
2759 &lt;rewriteSystem systemIdStartString="http://www.oasis-open.org/docbook/"
2760 rewritePrefix="file:///usr/share/xml/docbook/"/&gt;
2761...</pre>
2762
2763<p>A <code>rewriteSystem</code> is a very powerful instruction, it says that
2764any URI starting with a given prefix should be looked at another URI
2765constructed by replacing the prefix with an new one. In effect this acts like
2766a cache system for a full area of the Web. In practice it is extremely useful
2767with a file prefix if you have installed a copy of those resources on your
2768local system.</p>
2769<pre>...
2770&lt;delegatePublic publicIdStartString="-//OASIS//DTD XML Catalog //"
2771 catalog="file:///usr/share/xml/docbook.xml"/&gt;
2772&lt;delegatePublic publicIdStartString="-//OASIS//ENTITIES DocBook XML"
2773 catalog="file:///usr/share/xml/docbook.xml"/&gt;
2774&lt;delegatePublic publicIdStartString="-//OASIS//DTD DocBook XML"
2775 catalog="file:///usr/share/xml/docbook.xml"/&gt;
2776&lt;delegateSystem systemIdStartString="http://www.oasis-open.org/docbook/"
2777 catalog="file:///usr/share/xml/docbook.xml"/&gt;
2778&lt;delegateURI uriStartString="http://www.oasis-open.org/docbook/"
2779 catalog="file:///usr/share/xml/docbook.xml"/&gt;
2780...</pre>
2781
2782<p>Delegation is the core features which allows to build a tree of catalogs,
2783easier to maintain than a single catalog, based on Public Identifier, System
2784Identifier or URI prefixes it instructs the catalog software to look up
2785entries in another resource. This feature allow to build hierarchies of
2786catalogs, the set of entries presented should be sufficient to redirect the
2787resolution of all DocBook references to the specific catalog in
2788<code>/usr/share/xml/docbook.xml</code> this one in turn could delegate all
2789references for DocBook 4.2.1 to a specific catalog installed at the same time
2790as the DocBook resources on the local machine.</p>
2791
2792<h3><a name="reference">How to tune catalog usage:</a></h3>
2793
2794<p>The user can change the default catalog behaviour by redirecting queries
2795to its own set of catalogs, this can be done by setting the
2796<code>XML_CATALOG_FILES</code> environment variable to a list of catalogs, an
2797empty one should deactivate loading the default <code>/etc/xml/catalog</code>
2798default catalog</p>
2799
2800<h3><a name="validate">How to debug catalog processing:</a></h3>
2801
2802<p>Setting up the <code>XML_DEBUG_CATALOG</code> environment variable will
2803make libxml output debugging informations for each catalog operations, for
2804example:</p>
2805<pre>orchis:~/XML -&gt; xmllint --memory --noout test/ent2
2806warning: failed to load external entity "title.xml"
2807orchis:~/XML -&gt; export XML_DEBUG_CATALOG=
2808orchis:~/XML -&gt; xmllint --memory --noout test/ent2
2809Failed to parse catalog /etc/xml/catalog
2810Failed to parse catalog /etc/xml/catalog
2811warning: failed to load external entity "title.xml"
2812Catalogs cleanup
2813orchis:~/XML -&gt; </pre>
2814
2815<p>The test/ent2 references an entity, running the parser from memory makes
2816the base URI unavailable and the the "title.xml" entity cannot be loaded.
2817Setting up the debug environment variable allows to detect that an attempt is
2818made to load the <code>/etc/xml/catalog</code> but since it's not present the
2819resolution fails.</p>
2820
2821<p>But the most advanced way to debug XML catalog processing is to use the
2822<strong>xmlcatalog</strong> command shipped with libxml2, it allows to load
2823catalogs and make resolution queries to see what is going on. This is also
2824used for the regression tests:</p>
2825<pre>orchis:~/XML -&gt; ./xmlcatalog test/catalogs/docbook.xml \
2826 "-//OASIS//DTD DocBook XML V4.1.2//EN"
2827http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd
2828orchis:~/XML -&gt; </pre>
2829
2830<p>For debugging what is going on, adding one -v flags increase the verbosity
2831level to indicate the processing done (adding a second flag also indicate
2832what elements are recognized at parsing):</p>
2833<pre>orchis:~/XML -&gt; ./xmlcatalog -v test/catalogs/docbook.xml \
2834 "-//OASIS//DTD DocBook XML V4.1.2//EN"
2835Parsing catalog test/catalogs/docbook.xml's content
2836Found public match -//OASIS//DTD DocBook XML V4.1.2//EN
2837http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd
2838Catalogs cleanup
2839orchis:~/XML -&gt; </pre>
2840
2841<p>A shell interface is also available to debug and process multiple queries
2842(and for regression tests):</p>
2843<pre>orchis:~/XML -&gt; ./xmlcatalog -shell test/catalogs/docbook.xml \
2844 "-//OASIS//DTD DocBook XML V4.1.2//EN"
2845&gt; help
2846Commands available:
2847public PublicID: make a PUBLIC identifier lookup
2848system SystemID: make a SYSTEM identifier lookup
2849resolve PublicID SystemID: do a full resolver lookup
2850add 'type' 'orig' 'replace' : add an entry
2851del 'values' : remove values
2852dump: print the current catalog state
2853debug: increase the verbosity level
2854quiet: decrease the verbosity level
2855exit: quit the shell
2856&gt; public "-//OASIS//DTD DocBook XML V4.1.2//EN"
2857http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd
2858&gt; quit
2859orchis:~/XML -&gt; </pre>
2860
2861<p>This should be sufficient for most debugging purpose, this was actually
2862used heavily to debug the XML Catalog implementation itself.</p>
2863
2864<h3><a name="Declaring">How to create and maintain</a> catalogs:</h3>
2865
2866<p>Basically XML Catalogs are XML files, you can either use XML tools to
2867manage them or use <strong>xmlcatalog</strong> for this. The basic step is
2868to create a catalog the -create option provide this facility:</p>
2869<pre>orchis:~/XML -&gt; ./xmlcatalog --create tst.xml
2870&lt;?xml version="1.0"?&gt;
2871&lt;!DOCTYPE catalog PUBLIC "-//OASIS//DTD Entity Resolution XML Catalog V1.0//EN"
2872 "http://www.oasis-open.org/committees/entity/release/1.0/catalog.dtd"&gt;
2873&lt;catalog xmlns="urn:oasis:names:tc:entity:xmlns:xml:catalog"/&gt;
2874orchis:~/XML -&gt; </pre>
2875
2876<p>By default xmlcatalog does not overwrite the original catalog and save the
2877result on the standard output, this can be overridden using the -noout
2878option. The <code>-add</code> command allows to add entries in the
2879catalog:</p>
2880<pre>orchis:~/XML -&gt; ./xmlcatalog --noout --create --add "public" \
2881 "-//OASIS//DTD DocBook XML V4.1.2//EN" \
2882 http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd tst.xml
2883orchis:~/XML -&gt; cat tst.xml
2884&lt;?xml version="1.0"?&gt;
2885&lt;!DOCTYPE catalog PUBLIC "-//OASIS//DTD Entity Resolution XML Catalog V1.0//EN" \
2886 "http://www.oasis-open.org/committees/entity/release/1.0/catalog.dtd"&gt;
2887&lt;catalog xmlns="urn:oasis:names:tc:entity:xmlns:xml:catalog"&gt;
2888&lt;public publicId="-//OASIS//DTD DocBook XML V4.1.2//EN"
2889 uri="http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd"/&gt;
2890&lt;/catalog&gt;
2891orchis:~/XML -&gt; </pre>
2892
2893<p>The <code>-add</code> option will always take 3 parameters even if some of
2894the XML Catalog constructs (like nextCatalog) will have only a single
2895argument, just pass a third empty string, it will be ignored.</p>
2896
2897<p>Similarly the <code>-del</code> option remove matching entries from the
2898catalog:</p>
2899<pre>orchis:~/XML -&gt; ./xmlcatalog --del \
2900 "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd" tst.xml
2901&lt;?xml version="1.0"?&gt;
2902&lt;!DOCTYPE catalog PUBLIC "-//OASIS//DTD Entity Resolution XML Catalog V1.0//EN"
2903 "http://www.oasis-open.org/committees/entity/release/1.0/catalog.dtd"&gt;
2904&lt;catalog xmlns="urn:oasis:names:tc:entity:xmlns:xml:catalog"/&gt;
2905orchis:~/XML -&gt; </pre>
2906
2907<p>The catalog is now empty. Note that the matching of <code>-del</code> is
2908exact and would have worked in a similar fashion with the Public ID
2909string.</p>
2910
2911<p>This is rudimentary but should be sufficient to manage a not too complex
2912catalog tree of resources.</p>
2913
2914<h3><a name="implemento">The implementor corner quick review of the
2915API:</a></h3>
2916
2917<p>First, and like for every other module of libxml, there is an
2918automatically generated <a href="html/libxml-catalog.html">API page for
2919catalog support</a>.</p>
2920
2921<p>The header for the catalog interfaces should be included as:</p>
2922<pre>#include &lt;libxml/catalog.h&gt;</pre>
2923
2924<p>The API is voluntarily kept very simple. First it is not obvious that
2925applications really need access to it since it is the default behaviour of
2926libxml (Note: it is possible to completely override libxml default catalog by
2927using <a href="html/libxml-parser.html">xmlSetExternalEntityLoader</a> to
2928plug an application specific resolver).</p>
2929
2930<p>Basically libxml support 2 catalog lists:</p>
2931<ul>
2932 <li>the default one, global shared by all the application</li>
2933 <li>a per-document catalog, this one is built if the document uses the
2934 <code>oasis-xml-catalog</code> PIs to specify its own catalog list, it is
2935 associated to the parser context and destroyed when the parsing context
2936 is destroyed.</li>
2937</ul>
2938
2939<p>the document one will be used first if it exists.</p>
2940
2941<h4>Initialization routines:</h4>
2942
2943<p>xmlInitializeCatalog(), xmlLoadCatalog() and xmlLoadCatalogs() should be
2944used at startup to initialize the catalog, if the catalog should be
2945initialized with specific values xmlLoadCatalog() or xmlLoadCatalogs()
2946should be called before xmlInitializeCatalog() which would otherwise do a
2947default initialization first.</p>
2948
2949<p>The xmlCatalogAddLocal() call is used by the parser to grow the document
2950own catalog list if needed.</p>
2951
2952<h4>Preferences setup:</h4>
2953
2954<p>The XML Catalog spec requires the possibility to select default
2955preferences between public and system delegation,
2956xmlCatalogSetDefaultPrefer() allows this, xmlCatalogSetDefaults() and
2957xmlCatalogGetDefaults() allow to control if XML Catalogs resolution should
2958be forbidden, allowed for global catalog, for document catalog or both, the
2959default is to allow both.</p>
2960
2961<p>And of course xmlCatalogSetDebug() allows to generate debug messages
2962(through the xmlGenericError() mechanism).</p>
2963
2964<h4>Querying routines:</h4>
2965
2966<p>xmlCatalogResolve(), xmlCatalogResolveSystem(), xmlCatalogResolvePublic()
2967and xmlCatalogResolveURI() are relatively explicit if you read the XML
2968Catalog specification they correspond to section 7 algorithms, they should
2969also work if you have loaded an SGML catalog with a simplified semantic.</p>
2970
2971<p>xmlCatalogLocalResolve() and xmlCatalogLocalResolveURI() are the same but
2972operate on the document catalog list</p>
2973
2974<h4>Cleanup and Miscellaneous:</h4>
2975
2976<p>xmlCatalogCleanup() free-up the global catalog, xmlCatalogFreeLocal() is
2977the per-document equivalent.</p>
2978
2979<p>xmlCatalogAdd() and xmlCatalogRemove() are used to dynamically modify the
2980first catalog in the global list, and xmlCatalogDump() allows to dump a
2981catalog state, those routines are primarily designed for xmlcatalog, I'm not
2982sure that exposing more complex interfaces (like navigation ones) would be
2983really useful.</p>
2984
2985<p>The xmlParseCatalogFile() is a function used to load XML Catalog files,
2986it's similar as xmlParseFile() except it bypass all catalog lookups, it's
2987provided because this functionality may be useful for client tools.</p>
2988
2989<h4>threaded environments:</h4>
2990
2991<p>Since the catalog tree is built progressively, some care has been taken to
2992try to avoid troubles in multithreaded environments. The code is now thread
2993safe assuming that the libxml library has been compiled with threads
2994support.</p>
2995
2996<p></p>
2997
2998<h3><a name="Other">Other resources</a></h3>
2999
3000<p>The XML Catalog specification is relatively recent so there isn't much
3001literature to point at:</p>
3002<ul>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]3003 <li>You can find a good rant from Norm Walsh about <a
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3004 href="http://www.arbortext.com/Think_Tank/XML_Resources/Issue_Three/issue_three.html">the
3005 need for catalogs</a>, it provides a lot of context informations even if
Daniel Veillard93d3a472002-04-26 14:04:55 +0000[diff] [blame]3006 I don't agree with everything presented. Norm also wrote a more recent
3007 article <a
3008 href="http://wwws.sun.com/software/xml/developers/resolver/article/">XML
3009 entities and URI resolvers</a> describing them.</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3010 <li>An <a href="http://home.ccil.org/~cowan/XML/XCatalog.html">old XML
3011 catalog proposal</a> from John Cowan</li>
3012 <li>The <a href="http://www.rddl.org/">Resource Directory Description
3013 Language</a> (RDDL) another catalog system but more oriented toward
3014 providing metadata for XML namespaces.</li>
3015 <li>the page from the OASIS Technical <a
3016 href="http://www.oasis-open.org/committees/entity/">Committee on Entity
3017 Resolution</a> who maintains XML Catalog, you will find pointers to the
3018 specification update, some background and pointers to others tools
3019 providing XML Catalog support</li>
Daniel Veillard35e937a2002-01-19 22:21:54 +0000[diff] [blame]3020 <li>Here is a <a href="buildDocBookCatalog">shell script</a> to generate
3021 XML Catalogs for DocBook 4.1.2 . If it can write to the /etc/xml/
3022 directory, it will set-up /etc/xml/catalog and /etc/xml/docbook based on
3023 the resources found on the system. Otherwise it will just create
3024 ~/xmlcatalog and ~/dbkxmlcatalog and doing:
Daniel Veillardc575b992002-02-08 13:28:40 +0000[diff] [blame]3025 <p><code>export XMLCATALOG=$HOME/xmlcatalog</code></p>
Daniel Veillard35e937a2002-01-19 22:21:54 +0000[diff] [blame]3026 <p>should allow to process DocBook documentations without requiring
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]3027 network accesses for the DTD or stylesheets</p>
Daniel Veillard35e937a2002-01-19 22:21:54 +0000[diff] [blame]3028 </li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3029 <li>I have uploaded <a href="ftp://xmlsoft.org/test/dbk412catalog.tar.gz">a
Daniel Veillard35e937a2002-01-19 22:21:54 +0000[diff] [blame]3030 small tarball</a> containing XML Catalogs for DocBook 4.1.2 which seems
3031 to work fine for me too</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3032 <li>The <a href="http://www.xmlsoft.org/xmlcatalog_man.html">xmlcatalog
3033 manual page</a></li>
3034</ul>
3035
3036<p>If you have suggestions for corrections or additions, simply contact
3037me:</p>
3038
3039<h2><a name="library">The parser interfaces</a></h2>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3040
3041<p>This section is directly intended to help programmers getting bootstrapped
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3042using the XML library from the C language. It is not intended to be
3043extensive. I hope the automatically generated documents will provide the
3044completeness required, but as a separate set of documents. The interfaces of
3045the XML library are by principle low level, there is nearly zero abstraction.
3046Those interested in a higher level API should <a href="#DOM">look at
3047DOM</a>.</p>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]3048
Daniel Veillard9cb5ff42001-01-29 08:22:21 +0000[diff] [blame]3049<p>The <a href="html/libxml-parser.html">parser interfaces for XML</a> are
3050separated from the <a href="html/libxml-htmlparser.html">HTML parser
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3051interfaces</a>. Let's have a look at how the XML parser can be called:</p>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]3052
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3053<h3><a name="Invoking">Invoking the parser : the pull method</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3054
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3055<p>Usually, the first thing to do is to read an XML input. The parser accepts
3056documents either from in-memory strings or from files. The functions are
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3057defined in "parser.h":</p>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]3058<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3059 <dt><code>xmlDocPtr xmlParseMemory(char *buffer, int size);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3060 <dd><p>Parse a null-terminated string containing the document.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3061 </dd>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]3062</dl>
3063<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3064 <dt><code>xmlDocPtr xmlParseFile(const char *filename);</code></dt>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]3065 <dd><p>Parse an XML document contained in a (possibly compressed)
3066 file.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3067 </dd>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]3068</dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3069
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3070<p>The parser returns a pointer to the document structure (or NULL in case of
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]3071failure).</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3072
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3073<h3 id="Invoking1">Invoking the parser: the push method</h3>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]3074
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3075<p>In order for the application to keep the control when the document is
3076being fetched (which is common for GUI based programs) libxml provides a push
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3077interface, too, as of version 1.8.3. Here are the interface functions:</p>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]3078<pre>xmlParserCtxtPtr xmlCreatePushParserCtxt(xmlSAXHandlerPtr sax,
3079 void *user_data,
3080 const char *chunk,
3081 int size,
3082 const char *filename);
3083int xmlParseChunk (xmlParserCtxtPtr ctxt,
3084 const char *chunk,
3085 int size,
3086 int terminate);</pre>
3087
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3088<p>and here is a simple example showing how to use the interface:</p>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]3089<pre> FILE *f;
3090
3091 f = fopen(filename, "r");
3092 if (f != NULL) {
3093 int res, size = 1024;
3094 char chars[1024];
3095 xmlParserCtxtPtr ctxt;
3096
3097 res = fread(chars, 1, 4, f);
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3098 if (res &gt; 0) {
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]3099 ctxt = xmlCreatePushParserCtxt(NULL, NULL,
3100 chars, res, filename);
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3101 while ((res = fread(chars, 1, size, f)) &gt; 0) {
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]3102 xmlParseChunk(ctxt, chars, res, 0);
3103 }
3104 xmlParseChunk(ctxt, chars, 0, 1);
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3105 doc = ctxt-&gt;myDoc;
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]3106 xmlFreeParserCtxt(ctxt);
3107 }
3108 }</pre>
3109
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]3110<p>The HTML parser embedded into libxml also has a push interface; the
3111functions are just prefixed by "html" rather than "xml".</p>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]3112
3113<h3 id="Invoking2">Invoking the parser: the SAX interface</h3>
3114
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]3115<p>The tree-building interface makes the parser memory-hungry, first loading
3116the document in memory and then building the tree itself. Reading a document
3117without building the tree is possible using the SAX interfaces (see SAX.h and
3118<a href="http://www.daa.com.au/~james/gnome/xml-sax/xml-sax.html">James
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3119Henstridge's documentation</a>). Note also that the push interface can be
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3120limited to SAX: just use the two first arguments of
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]3121<code>xmlCreatePushParserCtxt()</code>.</p>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]3122
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]3123<h3><a name="Building">Building a tree from scratch</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3124
3125<p>The other way to get an XML tree in memory is by building it. Basically
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]3126there is a set of functions dedicated to building new elements. (These are
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3127also described in &lt;libxml/tree.h&gt;.) For example, here is a piece of
3128code that produces the XML document used in the previous examples:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3129<pre> #include &lt;libxml/tree.h&gt;
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]3130 xmlDocPtr doc;
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3131 xmlNodePtr tree, subtree;
3132
3133 doc = xmlNewDoc("1.0");
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3134 doc-&gt;children = xmlNewDocNode(doc, NULL, "EXAMPLE", NULL);
3135 xmlSetProp(doc-&gt;children, "prop1", "gnome is great");
3136 xmlSetProp(doc-&gt;children, "prop2", "&amp; linux too");
3137 tree = xmlNewChild(doc-&gt;children, NULL, "head", NULL);
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3138 subtree = xmlNewChild(tree, NULL, "title", "Welcome to Gnome");
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3139 tree = xmlNewChild(doc-&gt;children, NULL, "chapter", NULL);
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3140 subtree = xmlNewChild(tree, NULL, "title", "The Linux adventure");
3141 subtree = xmlNewChild(tree, NULL, "p", "bla bla bla ...");
3142 subtree = xmlNewChild(tree, NULL, "image", NULL);
3143 xmlSetProp(subtree, "href", "linus.gif");</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3144
3145<p>Not really rocket science ...</p>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3146
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]3147<h3><a name="Traversing">Traversing the tree</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3148
Daniel Veillard9cb5ff42001-01-29 08:22:21 +0000[diff] [blame]3149<p>Basically by <a href="html/libxml-tree.html">including "tree.h"</a> your
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3150code has access to the internal structure of all the elements of the tree.
3151The names should be somewhat simple like <strong>parent</strong>,
Daniel Veillard306be992000-07-03 12:38:45 +0000[diff] [blame]3152<strong>children</strong>, <strong>next</strong>, <strong>prev</strong>,
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3153<strong>properties</strong>, etc... For example, still with the previous
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]3154example:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3155<pre><code>doc-&gt;children-&gt;children-&gt;children</code></pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3156
3157<p>points to the title element,</p>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3158<pre>doc-&gt;children-&gt;children-&gt;next-&gt;children-&gt;children</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3159
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]3160<p>points to the text node containing the chapter title "The Linux
3161adventure".</p>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]3162
Daniel Veillardb24054a1999-12-18 15:32:46 +0000[diff] [blame]3163<p><strong>NOTE</strong>: XML allows <em>PI</em>s and <em>comments</em> to be
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3164present before the document root, so <code>doc-&gt;children</code> may point
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3165to an element which is not the document Root Element; a function
Daniel Veillard5cb5ab81999-12-21 15:35:29 +0000[diff] [blame]3166<code>xmlDocGetRootElement()</code> was added for this purpose.</p>
Daniel Veillardb24054a1999-12-18 15:32:46 +0000[diff] [blame]3167
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]3168<h3><a name="Modifying">Modifying the tree</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3169
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3170<p>Functions are provided for reading and writing the document content. Here
Daniel Veillard9cb5ff42001-01-29 08:22:21 +0000[diff] [blame]3171is an excerpt from the <a href="html/libxml-tree.html">tree API</a>:</p>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3172<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +0000[diff] [blame]3173 <dt><code>xmlAttrPtr xmlSetProp(xmlNodePtr node, const xmlChar *name, const
3174 xmlChar *value);</code></dt>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3175 <dd><p>This sets (or changes) an attribute carried by an ELEMENT node.
3176 The value can be NULL.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3177 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3178</dl>
3179<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +0000[diff] [blame]3180 <dt><code>const xmlChar *xmlGetProp(xmlNodePtr node, const xmlChar
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3181 *name);</code></dt>
Daniel Veillardc92c3042000-09-29 02:42:04 +0000[diff] [blame]3182 <dd><p>This function returns a pointer to new copy of the property
3183 content. Note that the user must deallocate the result.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3184 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3185</dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3186
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3187<p>Two functions are provided for reading and writing the text associated
3188with elements:</p>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3189<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +0000[diff] [blame]3190 <dt><code>xmlNodePtr xmlStringGetNodeList(xmlDocPtr doc, const xmlChar
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3191 *value);</code></dt>
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]3192 <dd><p>This function takes an "external" string and converts it to one
3193 text node or possibly to a list of entity and text nodes. All
3194 non-predefined entity references like &amp;Gnome; will be stored
3195 internally as entity nodes, hence the result of the function may not be
3196 a single node.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3197 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3198</dl>
3199<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +0000[diff] [blame]3200 <dt><code>xmlChar *xmlNodeListGetString(xmlDocPtr doc, xmlNodePtr list, int
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3201 inLine);</code></dt>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]3202 <dd><p>This function is the inverse of
3203 <code>xmlStringGetNodeList()</code>. It generates a new string
3204 containing the content of the text and entity nodes. Note the extra
3205 argument inLine. If this argument is set to 1, the function will expand
3206 entity references. For example, instead of returning the &amp;Gnome;
3207 XML encoding in the string, it will substitute it with its value (say,
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3208 "GNU Network Object Model Environment").</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3209 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3210</dl>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]3211
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]3212<h3><a name="Saving">Saving a tree</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3213
3214<p>Basically 3 options are possible:</p>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3215<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +0000[diff] [blame]3216 <dt><code>void xmlDocDumpMemory(xmlDocPtr cur, xmlChar**mem, int
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3217 *size);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3218 <dd><p>Returns a buffer into which the document has been saved.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3219 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3220</dl>
3221<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3222 <dt><code>extern void xmlDocDump(FILE *f, xmlDocPtr doc);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3223 <dd><p>Dumps a document to an open file descriptor.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3224 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3225</dl>
3226<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3227 <dt><code>int xmlSaveFile(const char *filename, xmlDocPtr cur);</code></dt>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]3228 <dd><p>Saves the document to a file. In this case, the compression
3229 interface is triggered if it has been turned on.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3230 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3231</dl>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]3232
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]3233<h3><a name="Compressio">Compression</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3234
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3235<p>The library transparently handles compression when doing file-based
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]3236accesses. The level of compression on saves can be turned on either globally
3237or individually for one file:</p>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3238<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3239 <dt><code>int xmlGetDocCompressMode (xmlDocPtr doc);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3240 <dd><p>Gets the document compression ratio (0-9).</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3241 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3242</dl>
3243<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3244 <dt><code>void xmlSetDocCompressMode (xmlDocPtr doc, int mode);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3245 <dd><p>Sets the document compression ratio.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3246 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3247</dl>
3248<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3249 <dt><code>int xmlGetCompressMode(void);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3250 <dd><p>Gets the default compression ratio.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3251 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3252</dl>
3253<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3254 <dt><code>void xmlSetCompressMode(int mode);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3255 <dd><p>Sets the default compression ratio.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3256 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3257</dl>
3258
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]3259<h2><a name="Entities">Entities or no entities</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3260
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3261<p>Entities in principle are similar to simple C macros. An entity defines an
3262abbreviation for a given string that you can reuse many times throughout the
3263content of your document. Entities are especially useful when a given string
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]3264may occur frequently within a document, or to confine the change needed to a
3265document to a restricted area in the internal subset of the document (at the
3266beginning). Example:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3267<pre>1 &lt;?xml version="1.0"?&gt;
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]32682 &lt;!DOCTYPE EXAMPLE SYSTEM "example.dtd" [
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]32693 &lt;!ENTITY xml "Extensible Markup Language"&gt;
32704 ]&gt;
32715 &lt;EXAMPLE&gt;
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]32726 &amp;xml;
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]32737 &lt;/EXAMPLE&gt;</pre>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3274
3275<p>Line 3 declares the xml entity. Line 6 uses the xml entity, by prefixing
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3276its name with '&amp;' and following it by ';' without any spaces added. There
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]3277are 5 predefined entities in libxml allowing you to escape characters with
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3278predefined meaning in some parts of the xml document content:
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3279<strong>&amp;lt;</strong> for the character '&lt;', <strong>&amp;gt;</strong>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3280for the character '&gt;', <strong>&amp;apos;</strong> for the character ''',
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3281<strong>&amp;quot;</strong> for the character '"', and
3282<strong>&amp;amp;</strong> for the character '&amp;'.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3283
3284<p>One of the problems related to entities is that you may want the parser to
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]3285substitute an entity's content so that you can see the replacement text in
3286your application. Or you may prefer to keep entity references as such in the
3287content to be able to save the document back without losing this usually
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3288precious information (if the user went through the pain of explicitly
3289defining entities, he may have a a rather negative attitude if you blindly
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]3290substitute them as saving time). The <a
Daniel Veillard9cb5ff42001-01-29 08:22:21 +0000[diff] [blame]3291href="html/libxml-parser.html#XMLSUBSTITUTEENTITIESDEFAULT">xmlSubstituteEntitiesDefault()</a>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3292function allows you to check and change the behaviour, which is to not
3293substitute entities by default.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3294
3295<p>Here is the DOM tree built by libxml for the previous document in the
3296default case:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3297<pre>/gnome/src/gnome-xml -&gt; ./xmllint --debug test/ent1
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3298DOCUMENT
3299version=1.0
3300 ELEMENT EXAMPLE
3301 TEXT
3302 content=
3303 ENTITY_REF
3304 INTERNAL_GENERAL_ENTITY xml
3305 content=Extensible Markup Language
3306 TEXT
3307 content=</pre>
3308
3309<p>And here is the result when substituting entities:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3310<pre>/gnome/src/gnome-xml -&gt; ./tester --debug --noent test/ent1
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3311DOCUMENT
3312version=1.0
3313 ELEMENT EXAMPLE
3314 TEXT
3315 content= Extensible Markup Language</pre>
3316
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3317<p>So, entities or no entities? Basically, it depends on your use case. I
3318suggest that you keep the non-substituting default behaviour and avoid using
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3319entities in your XML document or data if you are not willing to handle the
3320entity references elements in the DOM tree.</p>
3321
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3322<p>Note that at save time libxml enforces the conversion of the predefined
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3323entities where necessary to prevent well-formedness problems, and will also
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3324transparently replace those with chars (i.e. it will not generate entity
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3325reference elements in the DOM tree or call the reference() SAX callback when
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3326finding them in the input).</p>
3327
Daniel Veillard7b9c4b72000-08-25 16:26:50 +0000[diff] [blame]3328<p><span style="background-color: #FF0000">WARNING</span>: handling entities
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3329on top of the libxml SAX interface is difficult!!! If you plan to use
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]3330non-predefined entities in your documents, then the learning curve to handle
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3331then using the SAX API may be long. If you plan to use complex documents, I
Daniel Veillard7b9c4b72000-08-25 16:26:50 +0000[diff] [blame]3332strongly suggest you consider using the DOM interface instead and let libxml
Daniel Veillard8c6d6af2000-08-25 17:14:13 +0000[diff] [blame]3333deal with the complexity rather than trying to do it yourself.</p>
Daniel Veillard7b9c4b72000-08-25 16:26:50 +0000[diff] [blame]3334
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]3335<h2><a name="Namespaces">Namespaces</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3336
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]3337<p>The libxml library implements <a
3338href="http://www.w3.org/TR/REC-xml-names/">XML namespaces</a> support by
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]3339recognizing namespace constructs in the input, and does namespace lookup
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]3340automatically when building the DOM tree. A namespace declaration is
3341associated with an in-memory structure and all elements or attributes within
3342that namespace point to it. Hence testing the namespace is a simple and fast
3343equality operation at the user level.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3344
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]3345<p>I suggest that people using libxml use a namespace, and declare it in the
3346root element of their document as the default namespace. Then they don't need
3347to use the prefix in the content but we will have a basis for future semantic
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3348refinement and merging of data from different sources. This doesn't increase
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]3349the size of the XML output significantly, but significantly increases its
3350value in the long-term. Example:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3351<pre>&lt;mydoc xmlns="http://mydoc.example.org/schemas/"&gt;
3352 &lt;elem1&gt;...&lt;/elem1&gt;
3353 &lt;elem2&gt;...&lt;/elem2&gt;
3354&lt;/mydoc&gt;</pre>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3355
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]3356<p>The namespace value has to be an absolute URL, but the URL doesn't have to
3357point to any existing resource on the Web. It will bind all the element and
Daniel Veillardc0801af2002-05-28 16:28:42 +0000[diff] [blame]3358attributes with that URL. I suggest to use an URL within a domain you
3359control, and that the URL should contain some kind of version information if
3360possible. For example, <code>"http://www.gnome.org/gnumeric/1.0/"</code> is a
3361good namespace scheme.</p>
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]3362
3363<p>Then when you load a file, make sure that a namespace carrying the
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3364version-independent prefix is installed on the root element of your document,
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3365and if the version information don't match something you know, warn the user
3366and be liberal in what you accept as the input. Also do *not* try to base
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3367namespace checking on the prefix value. &lt;foo:text&gt; may be exactly the
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3368same as &lt;bar:text&gt; in another document. What really matters is the URI
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3369associated with the element or the attribute, not the prefix string (which is
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3370just a shortcut for the full URI). In libxml, element and attributes have an
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]3371<code>ns</code> field pointing to an xmlNs structure detailing the namespace
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3372prefix and its URI.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3373
3374<p>@@Interfaces@@</p>
3375
3376<p>@@Examples@@</p>
3377
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3378<p>Usually people object to using namespaces together with validity checking.
3379I will try to make sure that using namespaces won't break validity checking,
3380so even if you plan to use or currently are using validation I strongly
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]3381suggest adding namespaces to your document. A default namespace scheme
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3382<code>xmlns="http://...."</code> should not break validity even on less
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3383flexible parsers. Using namespaces to mix and differentiate content coming
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3384from multiple DTDs will certainly break current validation schemes. I will
3385try to provide ways to do this, but this may not be portable or
3386standardized.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3387
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3388<h2><a name="Upgrading">Upgrading 1.x code</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3389
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3390<p>Incompatible changes:</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3391
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3392<p>Version 2 of libxml is the first version introducing serious backward
3393incompatible changes. The main goals were:</p>
3394<ul>
3395 <li>a general cleanup. A number of mistakes inherited from the very early
3396 versions couldn't be changed due to compatibility constraints. Example
3397 the "childs" element in the nodes.</li>
3398 <li>Uniformization of the various nodes, at least for their header and link
3399 parts (doc, parent, children, prev, next), the goal is a simpler
3400 programming model and simplifying the task of the DOM implementors.</li>
3401 <li>better conformances to the XML specification, for example version 1.x
3402 had an heuristic to try to detect ignorable white spaces. As a result the
3403 SAX event generated were ignorableWhitespace() while the spec requires
3404 character() in that case. This also mean that a number of DOM node
3405 containing blank text may populate the DOM tree which were not present
3406 before.</li>
3407</ul>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3408
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3409<h3>How to fix libxml-1.x code:</h3>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3410
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3411<p>So client code of libxml designed to run with version 1.x may have to be
3412changed to compile against version 2.x of libxml. Here is a list of changes
3413that I have collected, they may not be sufficient, so in case you find other
3414change which are required, <a href="mailto:Daniel.Ïeillardw3.org">drop me a
3415mail</a>:</p>
3416<ol>
3417 <li>The package name have changed from libxml to libxml2, the library name
3418 is now -lxml2 . There is a new xml2-config script which should be used to
3419 select the right parameters libxml2</li>
3420 <li>Node <strong>childs</strong> field has been renamed
3421 <strong>children</strong> so s/childs/children/g should be applied
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]3422 (probability of having "childs" anywhere else is close to 0+</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3423 <li>The document don't have anymore a <strong>root</strong> element it has
3424 been replaced by <strong>children</strong> and usually you will get a
3425 list of element here. For example a Dtd element for the internal subset
3426 and it's declaration may be found in that list, as well as processing
3427 instructions or comments found before or after the document root element.
3428 Use <strong>xmlDocGetRootElement(doc)</strong> to get the root element of
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]3429 a document. Alternatively if you are sure to not reference DTDs nor have
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3430 PIs or comments before or after the root element
3431 s/-&gt;root/-&gt;children/g will probably do it.</li>
3432 <li>The white space issue, this one is more complex, unless special case of
3433 validating parsing, the line breaks and spaces usually used for indenting
3434 and formatting the document content becomes significant. So they are
3435 reported by SAX and if your using the DOM tree, corresponding nodes are
3436 generated. Too approach can be taken:
3437 <ol>
3438 <li>lazy one, use the compatibility call
3439 <strong>xmlKeepBlanksDefault(0)</strong> but be aware that you are
3440 relying on a special (and possibly broken) set of heuristics of
3441 libxml to detect ignorable blanks. Don't complain if it breaks or
3442 make your application not 100% clean w.r.t. to it's input.</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]3443 <li>the Right Way: change you code to accept possibly insignificant
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3444 blanks characters, or have your tree populated with weird blank text
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]3445 nodes. You can spot them using the commodity function
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3446 <strong>xmlIsBlankNode(node)</strong> returning 1 for such blank
3447 nodes.</li>
3448 </ol>
3449 <p>Note also that with the new default the output functions don't add any
3450 extra indentation when saving a tree in order to be able to round trip
3451 (read and save) without inflating the document with extra formatting
3452 chars.</p>
3453 </li>
3454 <li>The include path has changed to $prefix/libxml/ and the includes
3455 themselves uses this new prefix in includes instructions... If you are
3456 using (as expected) the
3457 <pre>xml2-config --cflags</pre>
3458 <p>output to generate you compile commands this will probably work out of
3459 the box</p>
3460 </li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]3461 <li>xmlDetectCharEncoding takes an extra argument indicating the length in
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3462 byte of the head of the document available for character detection.</li>
3463</ol>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3464
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3465<h3>Ensuring both libxml-1.x and libxml-2.x compatibility</h3>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3466
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3467<p>Two new version of libxml (1.8.11) and libxml2 (2.3.4) have been released
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]3468to allow smooth upgrade of existing libxml v1code while retaining
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3469compatibility. They offers the following:</p>
3470<ol>
3471 <li>similar include naming, one should use
3472 <strong>#include&lt;libxml/...&gt;</strong> in both cases.</li>
3473 <li>similar identifiers defined via macros for the child and root fields:
3474 respectively <strong>xmlChildrenNode</strong> and
3475 <strong>xmlRootNode</strong></li>
3476 <li>a new macro <strong>LIBXML_TEST_VERSION</strong> which should be
3477 inserted once in the client code</li>
3478</ol>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3479
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3480<p>So the roadmap to upgrade your existing libxml applications is the
3481following:</p>
3482<ol>
3483 <li>install the libxml-1.8.8 (and libxml-devel-1.8.8) packages</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]3484 <li>find all occurrences where the xmlDoc <strong>root</strong> field is
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3485 used and change it to <strong>xmlRootNode</strong></li>
Daniel Veillardc0801af2002-05-28 16:28:42 +0000[diff] [blame]3486 <li>similarly find all occurrences where the xmlNode
3487 <strong>childs</strong> field is used and change it to
3488 <strong>xmlChildrenNode</strong></li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3489 <li>add a <strong>LIBXML_TEST_VERSION</strong> macro somewhere in your
3490 <strong>main()</strong> or in the library init entry point</li>
3491 <li>Recompile, check compatibility, it should still work</li>
Daniel Veillardc0801af2002-05-28 16:28:42 +0000[diff] [blame]3492 <li>Change your configure script to look first for xml2-config and fall
3493 back using xml-config . Use the --cflags and --libs output of the command
3494 as the Include and Linking parameters needed to use libxml.</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3495 <li>install libxml2-2.3.x and libxml2-devel-2.3.x (libxml-1.8.y and
3496 libxml-devel-1.8.y can be kept simultaneously)</li>
3497 <li>remove your config.cache, relaunch your configuration mechanism, and
3498 recompile, if steps 2 and 3 were done right it should compile as-is</li>
3499 <li>Test that your application is still running correctly, if not this may
3500 be due to extra empty nodes due to formating spaces being kept in libxml2
3501 contrary to libxml1, in that case insert xmlKeepBlanksDefault(1) in your
3502 code before calling the parser (next to
3503 <strong>LIBXML_TEST_VERSION</strong> is a fine place).</li>
3504</ol>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3505
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3506<p>Following those steps should work. It worked for some of my own code.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3507
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3508<p>Let me put some emphasis on the fact that there is far more changes from
3509libxml 1.x to 2.x than the ones you may have to patch for. The overall code
3510has been considerably cleaned up and the conformance to the XML specification
3511has been drastically improved too. Don't take those changes as an excuse to
3512not upgrade, it may cost a lot on the long term ...</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3513
Daniel Veillard52dcab32001-10-30 12:51:17 +0000[diff] [blame]3514<h2><a name="Thread">Thread safety</a></h2>
3515
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]3516<p>Starting with 2.4.7, libxml makes provisions to ensure that concurrent
Daniel Veillard52dcab32001-10-30 12:51:17 +0000[diff] [blame]3517threads can safely work in parallel parsing different documents. There is
3518however a couple of things to do to ensure it:</p>
3519<ul>
3520 <li>configure the library accordingly using the --with-threads options</li>
3521 <li>call xmlInitParser() in the "main" thread before using any of the
3522 libxml API (except possibly selecting a different memory allocator)</li>
3523</ul>
3524
3525<p>Note that the thread safety cannot be ensured for multiple threads sharing
3526the same document, the locking must be done at the application level, libxml
3527exports a basic mutex and reentrant mutexes API in &lt;libxml/threads.h&gt;.
3528The parts of the library checked for thread safety are:</p>
3529<ul>
3530 <li>concurrent loading</li>
3531 <li>file access resolution</li>
3532 <li>catalog access</li>
3533 <li>catalog building</li>
3534 <li>entities lookup/accesses</li>
3535 <li>validation</li>
3536 <li>global variables per-thread override</li>
3537 <li>memory handling</li>
3538</ul>
3539
3540<p>XPath is supposed to be thread safe now, but this wasn't tested
3541seriously.</p>
3542
Daniel Veillard35008381999-10-25 13:15:52 +0000[diff] [blame]3543<h2><a name="DOM"></a><a name="Principles">DOM Principles</a></h2>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3544
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3545<p><a href="http://www.w3.org/DOM/">DOM</a> stands for the <em>Document
3546Object Model</em>; this is an API for accessing XML or HTML structured
3547documents. Native support for DOM in Gnome is on the way (module gnome-dom),
3548and will be based on gnome-xml. This will be a far cleaner interface to
3549manipulate XML files within Gnome since it won't expose the internal
3550structure.</p>
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3551
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3552<p>The current DOM implementation on top of libxml is the <a
Daniel Veillarda47fb3d2001-03-25 17:23:49 +0000[diff] [blame]3553href="http://cvs.gnome.org/lxr/source/gdome2/">gdome2 Gnome module</a>, this
3554is a full DOM interface, thanks to Paolo Casarini, check the <a
3555href="http://www.cs.unibo.it/~casarini/gdome2/">Gdome2 homepage</a> for more
3556informations.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3557
Daniel Veillard35008381999-10-25 13:15:52 +0000[diff] [blame]3558<h2><a name="Example"></a><a name="real">A real example</a></h2>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3559
3560<p>Here is a real size example, where the actual content of the application
3561data is not kept in the DOM tree but uses internal structures. It is based on
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3562a proposal to keep a database of jobs related to Gnome, with an XML based
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3563storage structure. Here is an <a href="gjobs.xml">XML encoded jobs
3564base</a>:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3565<pre>&lt;?xml version="1.0"?&gt;
3566&lt;gjob:Helping xmlns:gjob="http://www.gnome.org/some-location"&gt;
3567 &lt;gjob:Jobs&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3568
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3569 &lt;gjob:Job&gt;
3570 &lt;gjob:Project ID="3"/&gt;
3571 &lt;gjob:Application&gt;GBackup&lt;/gjob:Application&gt;
3572 &lt;gjob:Category&gt;Development&lt;/gjob:Category&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3573
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3574 &lt;gjob:Update&gt;
3575 &lt;gjob:Status&gt;Open&lt;/gjob:Status&gt;
3576 &lt;gjob:Modified&gt;Mon, 07 Jun 1999 20:27:45 -0400 MET DST&lt;/gjob:Modified&gt;
3577 &lt;gjob:Salary&gt;USD 0.00&lt;/gjob:Salary&gt;
3578 &lt;/gjob:Update&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3579
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3580 &lt;gjob:Developers&gt;
3581 &lt;gjob:Developer&gt;
3582 &lt;/gjob:Developer&gt;
3583 &lt;/gjob:Developers&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3584
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3585 &lt;gjob:Contact&gt;
3586 &lt;gjob:Person&gt;Nathan Clemons&lt;/gjob:Person&gt;
3587 &lt;gjob:Email&gt;nathan@windsofstorm.net&lt;/gjob:Email&gt;
3588 &lt;gjob:Company&gt;
3589 &lt;/gjob:Company&gt;
3590 &lt;gjob:Organisation&gt;
3591 &lt;/gjob:Organisation&gt;
3592 &lt;gjob:Webpage&gt;
3593 &lt;/gjob:Webpage&gt;
3594 &lt;gjob:Snailmail&gt;
3595 &lt;/gjob:Snailmail&gt;
3596 &lt;gjob:Phone&gt;
3597 &lt;/gjob:Phone&gt;
3598 &lt;/gjob:Contact&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3599
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3600 &lt;gjob:Requirements&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3601 The program should be released as free software, under the GPL.
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3602 &lt;/gjob:Requirements&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3603
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3604 &lt;gjob:Skills&gt;
3605 &lt;/gjob:Skills&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3606
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3607 &lt;gjob:Details&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3608 A GNOME based system that will allow a superuser to configure
3609 compressed and uncompressed files and/or file systems to be backed
3610 up with a supported media in the system. This should be able to
3611 perform via find commands generating a list of files that are passed
3612 to tar, dd, cpio, cp, gzip, etc., to be directed to the tape machine
3613 or via operations performed on the filesystem itself. Email
3614 notification and GUI status display very important.
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3615 &lt;/gjob:Details&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3616
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3617 &lt;/gjob:Job&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3618
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3619 &lt;/gjob:Jobs&gt;
3620&lt;/gjob:Helping&gt;</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3621
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3622<p>While loading the XML file into an internal DOM tree is a matter of
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]3623calling only a couple of functions, browsing the tree to gather the data and
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3624generate the internal structures is harder, and more error prone.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3625
3626<p>The suggested principle is to be tolerant with respect to the input
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3627structure. For example, the ordering of the attributes is not significant,
3628the XML specification is clear about it. It's also usually a good idea not to
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]3629depend on the order of the children of a given node, unless it really makes
3630things harder. Here is some code to parse the information for a person:</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3631<pre>/*
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3632 * A person record
3633 */
3634typedef struct person {
3635 char *name;
3636 char *email;
3637 char *company;
3638 char *organisation;
3639 char *smail;
3640 char *webPage;
3641 char *phone;
3642} person, *personPtr;
3643
3644/*
3645 * And the code needed to parse it
3646 */
3647personPtr parsePerson(xmlDocPtr doc, xmlNsPtr ns, xmlNodePtr cur) {
3648 personPtr ret = NULL;
3649
3650DEBUG("parsePerson\n");
3651 /*
3652 * allocate the struct
3653 */
3654 ret = (personPtr) malloc(sizeof(person));
3655 if (ret == NULL) {
3656 fprintf(stderr,"out of memory\n");
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3657 return(NULL);
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3658 }
3659 memset(ret, 0, sizeof(person));
3660
3661 /* We don't care what the top level element name is */
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3662 cur = cur-&gt;xmlChildrenNode;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3663 while (cur != NULL) {
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3664 if ((!strcmp(cur-&gt;name, "Person")) &amp;&amp; (cur-&gt;ns == ns))
3665 ret-&gt;name = xmlNodeListGetString(doc, cur-&gt;xmlChildrenNode, 1);
3666 if ((!strcmp(cur-&gt;name, "Email")) &amp;&amp; (cur-&gt;ns == ns))
3667 ret-&gt;email = xmlNodeListGetString(doc, cur-&gt;xmlChildrenNode, 1);
3668 cur = cur-&gt;next;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3669 }
3670
3671 return(ret);
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3672}</pre>
3673
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3674<p>Here are a couple of things to notice:</p>
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3675<ul>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3676 <li>Usually a recursive parsing style is the more convenient one: XML data
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]3677 is by nature subject to repetitive constructs and usually exhibits highly
3678 structured patterns.</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3679 <li>The two arguments of type <em>xmlDocPtr</em> and <em>xmlNsPtr</em>,
3680 i.e. the pointer to the global XML document and the namespace reserved to
3681 the application. Document wide information are needed for example to
3682 decode entities and it's a good coding practice to define a namespace for
3683 your application set of data and test that the element and attributes
3684 you're analyzing actually pertains to your application space. This is
3685 done by a simple equality test (cur-&gt;ns == ns).</li>
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]3686 <li>To retrieve text and attributes value, you can use the function
3687 <em>xmlNodeListGetString</em> to gather all the text and entity reference
3688 nodes generated by the DOM output and produce an single text string.</li>
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3689</ul>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3690
3691<p>Here is another piece of code used to parse another level of the
3692structure:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3693<pre>#include &lt;libxml/tree.h&gt;
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]3694/*
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3695 * a Description for a Job
3696 */
3697typedef struct job {
3698 char *projectID;
3699 char *application;
3700 char *category;
3701 personPtr contact;
3702 int nbDevelopers;
3703 personPtr developers[100]; /* using dynamic alloc is left as an exercise */
3704} job, *jobPtr;
3705
3706/*
3707 * And the code needed to parse it
3708 */
3709jobPtr parseJob(xmlDocPtr doc, xmlNsPtr ns, xmlNodePtr cur) {
3710 jobPtr ret = NULL;
3711
3712DEBUG("parseJob\n");
3713 /*
3714 * allocate the struct
3715 */
3716 ret = (jobPtr) malloc(sizeof(job));
3717 if (ret == NULL) {
3718 fprintf(stderr,"out of memory\n");
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3719 return(NULL);
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3720 }
3721 memset(ret, 0, sizeof(job));
3722
3723 /* We don't care what the top level element name is */
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3724 cur = cur-&gt;xmlChildrenNode;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3725 while (cur != NULL) {
3726
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3727 if ((!strcmp(cur-&gt;name, "Project")) &amp;&amp; (cur-&gt;ns == ns)) {
3728 ret-&gt;projectID = xmlGetProp(cur, "ID");
3729 if (ret-&gt;projectID == NULL) {
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3730 fprintf(stderr, "Project has no ID\n");
3731 }
3732 }
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3733 if ((!strcmp(cur-&gt;name, "Application")) &amp;&amp; (cur-&gt;ns == ns))
3734 ret-&gt;application = xmlNodeListGetString(doc, cur-&gt;xmlChildrenNode, 1);
3735 if ((!strcmp(cur-&gt;name, "Category")) &amp;&amp; (cur-&gt;ns == ns))
3736 ret-&gt;category = xmlNodeListGetString(doc, cur-&gt;xmlChildrenNode, 1);
3737 if ((!strcmp(cur-&gt;name, "Contact")) &amp;&amp; (cur-&gt;ns == ns))
3738 ret-&gt;contact = parsePerson(doc, ns, cur);
3739 cur = cur-&gt;next;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3740 }
3741
3742 return(ret);
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3743}</pre>
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3744
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]3745<p>Once you are used to it, writing this kind of code is quite simple, but
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]3746boring. Ultimately, it could be possible to write stubbers taking either C
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3747data structure definitions, a set of XML examples or an XML DTD and produce
3748the code needed to import and export the content between C data and XML
3749storage. This is left as an exercise to the reader :-)</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3750
Daniel Veillard6f0adb52000-07-03 11:41:26 +0000[diff] [blame]3751<p>Feel free to use <a href="example/gjobread.c">the code for the full C
3752parsing example</a> as a template, it is also available with Makefile in the
3753Gnome CVS base under gnome-xml/example</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3754
Daniel Veillardc310d562000-06-23 18:32:15 +0000[diff] [blame]3755<h2><a name="Contributi">Contributions</a></h2>
3756<ul>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3757 <li>Bjorn Reese, William Brack and Thomas Broyer have provided a number of
3758 patches, Gary Pennington worked on the validation API, threading support
3759 and Solaris port.</li>
3760 <li>John Fleck helps maintaining the documentation and man pages.</li>
Daniel Veillardb2fb8ed2002-04-01 09:33:12 +0000[diff] [blame]3761 <li><a href="mailto:igor@stud.fh-frankfurt.de">Igor Zlatkovic</a> is now
3762 the maintainer of the Windows port, <a
Daniel Veillard95189532001-07-26 18:30:26 +0000[diff] [blame]3763 href="http://www.fh-frankfurt.de/~igor/projects/libxml/index.html">he
3764 provides binaries</a></li>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]3765 <li><a href="mailto:Gary.Pennington@sun.com">Gary Pennington</a> provides
3766 <a href="http://garypennington.net/libxml2/">Solaris binaries</a></li>
Daniel Veillarde356c282001-03-10 12:32:04 +0000[diff] [blame]3767 <li><a
3768 href="http://mail.gnome.org/archives/xml/2001-March/msg00014.html">Matt
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]3769 Sergeant</a> developed <a
3770 href="http://axkit.org/download/">XML::LibXSLT</a>, a Perl wrapper for
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]3771 libxml2/libxslt as part of the <a href="http://axkit.com/">AxKit XML
3772 application server</a></li>
3773 <li><a href="mailto:fnatter@gmx.net">Felix Natter</a> and <a
3774 href="mailto:geertk@ai.rug.nl">Geert Kloosterman</a> provide <a
Daniel Veillardca989762001-06-23 17:39:29 +0000[diff] [blame]3775 href="libxml-doc.el">an emacs module</a> to lookup libxml(2) functions
Daniel Veillard3f6f7f62000-06-30 17:58:25 +0000[diff] [blame]3776 documentation</li>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]3777 <li><a href="mailto:sherwin@nlm.nih.gov">Ziying Sherwin</a> provided <a
3778 href="http://xmlsoft.org/messages/0488.html">man pages</a></li>
Daniel Veillard5168dbf2001-07-07 00:18:23 +0000[diff] [blame]3779 <li>there is a module for <a
3780 href="http://acs-misc.sourceforge.net/nsxml.html">libxml/libxslt support
3781 in OpenNSD/AOLServer</a></li>
Daniel Veillard2d347fa2002-03-17 10:34:11 +0000[diff] [blame]3782 <li><a href="mailto:dkuhlman@cutter.rexx.com">Dave Kuhlman</a> provided the
3783 first version of libxml/libxslt <a
3784 href="http://www.rexx.com/~dkuhlman">wrappers for Python</a></li>
Daniel Veillard1aadc442001-11-28 13:10:32 +0000[diff] [blame]3785 <li>Petr Kozelka provides <a
3786 href="http://sourceforge.net/projects/libxml2-pas">Pascal units to glue
3787 libxml2</a> with Kylix and Delphi and other Pascal compilers</li>
Daniel Veillard2d347fa2002-03-17 10:34:11 +0000[diff] [blame]3788 <li><a href="mailto:aleksey@aleksey.com">Aleksey Sanin</a> implemented the
3789 <a href="http://www.w3.org/Signature/">XML Canonicalization and XML
3790 Digital Signature</a> <a
3791 href="http://www.aleksey.com/xmlsec/">implementations for libxml2</a></li>
Daniel Veillardc310d562000-06-23 18:32:15 +0000[diff] [blame]3792</ul>
3793
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3794<p></p>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]3795</body>
3796</html>