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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>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]423 <li><a href="mailto:james@daa.com.au">James Henstridge</a> wrote <a
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]424 href="http://www.daa.com.au/~james/gnome/xml-sax/xml-sax.html">some nice
425 documentation</a> explaining how to use the libxml SAX interface.</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]426 <li>George Lebl wrote <a
427 href="http://www-4.ibm.com/software/developer/library/gnome3/">an article
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]428 for IBM developerWorks</a> about using libxml.</li>
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]429 <li>Check <a href="http://cvs.gnome.org/lxr/source/gnome-xml/TODO">the TODO
430 file</a></li>
431 <li>Read the <a href="upgrade.html">1.x to 2.x upgrade path</a>. If you are
432 starting a new project using libxml you should really use the 2.x
433 version.</li>
Daniel Veillard845cce42002-01-09 11:51:37 +0000[diff] [blame]434 <li>And don't forget to look at the <a
435 href="http://mail.gnome.org/archives/xml/">mailing-list archive</a>.</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]436</ol>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]437
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]438<h2><a name="Reporting">Reporting bugs and getting help</a></h2>
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000[diff] [blame]439
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]440<p>Well, bugs or missing features are always possible, and I will make a
441point of fixing them in a timely fashion. The best way to report a bug is to
442use the <a href="http://bugzilla.gnome.org/buglist.cgi?product=libxml">Gnome
443bug tracking database</a> (make sure to use the "libxml" module name). I look
444at 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]445still open. Be sure to specify that the bug is for the package libxml.</p>
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000[diff] [blame]446
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]447<p>There is also a mailing-list <a
Daniel Veillard3197f162001-04-04 00:40:08 +0000[diff] [blame]448href="mailto:xml@gnome.org">xml@gnome.org</a> for libxml, with an <a
449href="http://mail.gnome.org/archives/xml/">on-line archive</a> (<a
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]450href="http://xmlsoft.org/messages">old</a>). To subscribe to this list,
451please visit the <a
452href="http://mail.gnome.org/mailman/listinfo/xml">associated Web</a> page and
453follow the instructions. <strong>Do not send code, I won't debug it</strong>
454(but patches are really appreciated!).</p>
Daniel Veillard234547b2001-07-05 09:46:10 +0000[diff] [blame]455
Daniel Veillard008186f2001-09-13 14:24:44 +0000[diff] [blame]456<p>Check the following <strong><span style="color: #FF0000">before
457posting</span></strong>:</p>
Daniel Veillard234547b2001-07-05 09:46:10 +0000[diff] [blame]458<ul>
Daniel Veillarddadd0872001-09-15 09:21:44 +0000[diff] [blame]459 <li>read the <a href="FAQ.html">FAQ</a></li>
Daniel Veillard234547b2001-07-05 09:46:10 +0000[diff] [blame]460 <li>make sure you are <a href="ftp://xmlsoft.org/">using a recent
461 version</a>, and that the problem still shows up in those</li>
462 <li>check the <a href="http://mail.gnome.org/archives/xml/">list
463 archives</a> to see if the problem was reported already, in this case
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]464 there is probably a fix available, similarly check the <a
Daniel Veillarde7ead2d2001-08-22 23:44:09 +0000[diff] [blame]465 href="http://bugzilla.gnome.org/buglist.cgi?product=libxml">registered
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]466 open bugs</a></li>
Daniel Veillard234547b2001-07-05 09:46:10 +0000[diff] [blame]467 <li>make sure you can reproduce the bug with xmllint or one of the test
468 programs found in source in the distribution</li>
469 <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]470 attachment)</li>
Daniel Veillard234547b2001-07-05 09:46:10 +0000[diff] [blame]471</ul>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]472
Daniel Veillarddadd0872001-09-15 09:21:44 +0000[diff] [blame]473<p>Then send the bug with associated informations to reproduce it to the <a
Daniel Veillard33a67802001-03-07 09:44:02 +0000[diff] [blame]474href="mailto:xml@gnome.org">xml@gnome.org</a> list; if it's really libxml
Daniel Veillard008186f2001-09-13 14:24:44 +0000[diff] [blame]475related I will approve it.. Please do not send me mail directly, it makes
476things really harder to track and in some cases I'm not the best person to
477answer a given question, ask the list instead.</p>
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000[diff] [blame]478
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]479<p>Of course, bugs reported with a suggested patch for fixing them will
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]480probably be processed faster.</p>
481
482<p>If you're looking for help, a quick look at <a
Daniel Veillardf7ed3362001-08-17 12:01:21 +0000[diff] [blame]483href="http://mail.gnome.org/archives/xml/">the list archive</a> may actually
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]484provide the answer, I usually send source samples when answering libxml usage
Daniel Veillard6f0adb52000-07-03 11:41:26 +0000[diff] [blame]485questions. The <a href="http://xmlsoft.org/html/book1.html">auto-generated
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]486documentation</a> is not as polished as I would like (i need to learn more
487about DocBook), but it's a good starting point.</p>
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]488
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]489<h2><a name="help">How to help</a></h2>
490
491<p>You can help the project in various ways, the best thing to do first is to
492subscribe to the mailing-list as explained before, check the <a
Daniel Veillardf7ed3362001-08-17 12:01:21 +0000[diff] [blame]493href="http://mail.gnome.org/archives/xml/">archives </a>and the <a
494href="http://bugzilla.gnome.org/buglist.cgi?product=libxml">Gnome bug
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]495database:</a>:</p>
496<ol>
497 <li>provide patches when you find problems</li>
Daniel Veillard189446d2000-10-13 10:23:06 +0000[diff] [blame]498 <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]499 be integrated in all cases but help pinpointing portability problems
500 and</li>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]501 <li>provide documentation fixes (either as patches to the code comments or
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]502 as HTML diffs).</li>
503 <li>provide new documentations pieces (translations, examples, etc ...)</li>
504 <li>Check the TODO file and try to close one of the items</li>
505 <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]506 provide a fix. <a href="mailto:daniel@veillard.com">Get in touch with me
507 </a>before to avoid synchronization problems and check that the suggested
508 fix will fit in nicely :-)</li>
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]509</ol>
510
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]511<h2><a name="Downloads">Downloads</a></h2>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]512
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]513<p>The latest versions of libxml can be found on <a
Daniel Veillard20c8cf22001-06-26 22:47:36 +0000[diff] [blame]514href="ftp://xmlsoft.org/">xmlsoft.org</a> (<a
515href="ftp://speakeasy.rpmfind.net/pub/libxml/">Seattle</a>, <a
516href="ftp://fr.rpmfind.net/pub/libxml/">France</a>) or on the <a
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]517href="ftp://ftp.gnome.org/pub/GNOME/MIRRORS.html">Gnome FTP server</a> either
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]518as a <a href="ftp://ftp.gnome.org/pub/GNOME/stable/sources/libxml/">source
Daniel Veillard306be992000-07-03 12:38:45 +0000[diff] [blame]519archive</a> or <a
Daniel Veillarda41123c2001-04-22 19:31:20 +0000[diff] [blame]520href="ftp://ftp.gnome.org/pub/GNOME/stable/redhat/i386/libxml/">RPM
Daniel Veillard0bfbb422002-04-26 09:21:45 +0000[diff] [blame]521packages</a>, Antonin Sprinzl also provide <a
522href="ftp://gd.tuwien.ac.at/pub/libxml/">a mirror in Austria</a>. (NOTE that
523you need both the <a
Daniel Veillardc19fccc2000-07-03 11:52:01 +0000[diff] [blame]524href="http://rpmfind.net/linux/RPM/libxml2.html">libxml(2)</a> and <a
525href="http://rpmfind.net/linux/RPM/libxml2-devel.html">libxml(2)-devel</a>
Daniel Veillard95189532001-07-26 18:30:26 +0000[diff] [blame]526packages installed to compile applications using libxml.) <a
Daniel Veillardb2fb8ed2002-04-01 09:33:12 +0000[diff] [blame]527href="mailto:igor@stud.fh-frankfurt.de">Igor Zlatkovic</a> is now the
528maintainer of the Windows port, <a
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]529href="http://www.fh-frankfurt.de/~igor/projects/libxml/index.html">he
Daniel Veillardc6271d22001-10-27 07:50:58 +0000[diff] [blame]530provides binaries</a>. <a href="mailto:Gary.Pennington@sun.com">Gary
Daniel Veillard1aadc442001-11-28 13:10:32 +0000[diff] [blame]531Pennington</a> provides <a href="http://garypennington.net/libxml2/">Solaris
532binaries</a>.</p>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]533
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]534<p><a name="Snapshot">Snapshot:</a></p>
535<ul>
536 <li>Code from the W3C cvs base libxml <a
Daniel Veillard33a67802001-03-07 09:44:02 +0000[diff] [blame]537 href="ftp://xmlsoft.org/cvs-snapshot.tar.gz">cvs-snapshot.tar.gz</a></li>
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]538 <li>Docs, content of the web site, the list archive included <a
Daniel Veillard33a67802001-03-07 09:44:02 +0000[diff] [blame]539 href="ftp://xmlsoft.org/libxml-docs.tar.gz">libxml-docs.tar.gz</a></li>
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]540</ul>
541
Daniel Veillardc6271d22001-10-27 07:50:58 +0000[diff] [blame]542<p><a name="Contribs">Contributions:</a></p>
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]543
544<p>I do accept external contributions, especially if compiling on another
Daniel Veillardc6271d22001-10-27 07:50:58 +0000[diff] [blame]545platform, get in touch with me to upload the package, wrappers for various
Daniel Veillard51095312001-10-28 18:51:57 +0000[diff] [blame]546languages have been provided, and can be found in the <a
547href="contribs.html">contrib section</a></p>
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]548
Daniel Veillard82687162001-01-22 15:32:01 +0000[diff] [blame]549<p>Libxml is also available from CVS:</p>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]550<ul>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]551 <li><p>The <a
552 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]553 CVS base</a>. Check the <a
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]554 href="http://developer.gnome.org/tools/cvs.html">Gnome CVS Tools</a>
555 page; the CVS module is <b>gnome-xml</b>.</p>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]556 </li>
Daniel Veillard82687162001-01-22 15:32:01 +0000[diff] [blame]557 <li>The <strong>libxslt</strong> module is also present there</li>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]558</ul>
559
560<h2><a name="News">News</a></h2>
561
Daniel Veillard944b5ff1999-12-15 19:08:24 +0000[diff] [blame]562<h3>CVS only : check the <a
563href="http://cvs.gnome.org/lxr/source/gnome-xml/ChangeLog">Changelog</a> file
Daniel Veillard189446d2000-10-13 10:23:06 +0000[diff] [blame]564for a really accurate description</h3>
Daniel Veillardab8500d2000-10-15 21:06:19 +0000[diff] [blame]565
Daniel Veillarde6d8e202002-05-02 06:11:10 +0000[diff] [blame]566<p>Items not finished and worked on, get in touch with the list if you want
567to test those</p>
Daniel Veillardab8500d2000-10-15 21:06:19 +0000[diff] [blame]568<ul>
Daniel Veillardcf27f7c2002-04-30 07:12:39 +0000[diff] [blame]569 <li>Finishing up <a href="http://www.w3.org/TR/xmlschema-1/">XML
570 Schemas</a> and <a href="http://www.w3.org/TR/xinclude">XInclude</a></li>
571</ul>
572
Daniel Veillardc0801af2002-05-28 16:28:42 +0000[diff] [blame^]573<h3>2.4.22: May 27 2002</h3>
574<ul>
575 <li>a number of bug fixes: configure scripts, base handling, parser, memory
576 usage, HTML parser, XPath, documentation (Christian Cornelssen),
577 indentation, URI parsing </li>
578 <li>Optimizations for XMLSec, fixing and making public some of the network
579 protocol handlers (Aleksey)</li>
580 <li>performance patch from Gary Pennington</li>
581 <li>Charles Bozeman provided date and time support for XML Schemas
582 datatypes</li>
583</ul>
584
Daniel Veillardcf27f7c2002-04-30 07:12:39 +0000[diff] [blame]585<h3>2.4.21: Apr 29 2002</h3>
586
587<p>This release is both a bug fix release and also contains the early XML
588Schemas <a href="http://www.w3.org/TR/xmlschema-1/">structures</a> and <a
589href="http://www.w3.org/TR/xmlschema-2/">datatypes</a> code, beware, all
590interfaces are likely to change, there is huge holes, it is clearly a work in
591progress and don't even think of putting this code in a production system,
Daniel Veillarde6d8e202002-05-02 06:11:10 +0000[diff] [blame]592it's actually not compiled in by default. The real fixes are:</p>
Daniel Veillardcf27f7c2002-04-30 07:12:39 +0000[diff] [blame]593<ul>
594 <li>a couple of bugs or limitations introduced in 2.4.20</li>
595 <li>patches for Borland C++ and MSC by Igor</li>
596 <li>some fixes on XPath strings and conformance patches by Richard
597 Jinks</li>
598 <li>patch from Aleksey for the ExcC14N specification</li>
599 <li>OSF/1 bug fix by Bjorn</li>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]600</ul>
601
Daniel Veillarda7084cd2002-04-15 17:12:47 +0000[diff] [blame]602<h3>2.4.20: Apr 15 2002</h3>
603<ul>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]604 <li>bug fixes: file descriptor leak, XPath, HTML output, DTD validation</li>
Daniel Veillarda7084cd2002-04-15 17:12:47 +0000[diff] [blame]605 <li>XPath conformance testing by Richard Jinks</li>
606 <li>Portability fixes: Solaris, MPE/iX, Windows, OSF/1, python bindings,
607 libxml.m4</li>
608</ul>
609
Daniel Veillard19274092002-03-25 16:48:03 +0000[diff] [blame]610<h3>2.4.19: Mar 25 2002</h3>
611<ul>
612 <li>bug fixes: half a dozen XPath bugs, Validation, ISO-Latin to UTF8
613 encoder</li>
614 <li>portability fixes in the HTTP code</li>
Daniel Veillardb2fb8ed2002-04-01 09:33:12 +0000[diff] [blame]615 <li>memory allocation checks using valgrind, and profiling tests</li>
Daniel Veillard19274092002-03-25 16:48:03 +0000[diff] [blame]616 <li>revamp of the Windows build and Makefiles</li>
617</ul>
618
Daniel Veillard34ce8be2002-03-18 19:37:11 +0000[diff] [blame]619<h3>2.4.18: Mar 18 2002</h3>
620<ul>
621 <li>bug fixes: tree, SAX, canonicalization, validation, portability,
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]622 XPath</li>
Daniel Veillard34ce8be2002-03-18 19:37:11 +0000[diff] [blame]623 <li>removed the --with-buffer option it was becoming unmaintainable</li>
624 <li>serious cleanup of the Python makefiles</li>
625 <li>speedup patch to XPath very effective for DocBook stylesheets</li>
626 <li>Fixes for Windows build, cleanup of the documentation</li>
627</ul>
628
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]629<h3>2.4.17: Mar 8 2002</h3>
630<ul>
631 <li>a lot of bug fixes, including "namespace nodes have no parents in
632 XPath"</li>
633 <li>fixed/improved the Python wrappers, added more examples and more
634 regression tests, XPath extension functions can now return node-sets</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]635 <li>added the XML Canonicalization support from Aleksey Sanin</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]636</ul>
637
Daniel Veillard5f4b5992002-02-20 10:22:49 +0000[diff] [blame]638<h3>2.4.16: Feb 20 2002</h3>
639<ul>
640 <li>a lot of bug fixes, most of them were triggered by the XML Testsuite
641 from OASIS and W3C. Compliance has been significantly improved.</li>
642 <li>a couple of portability fixes too.</li>
643</ul>
644
Daniel Veillard397ff112002-02-11 18:27:20 +0000[diff] [blame]645<h3>2.4.15: Feb 11 2002</h3>
646<ul>
647 <li>Fixed the Makefiles, especially the python module ones</li>
648 <li>A few bug fixes and cleanup</li>
649 <li>Includes cleanup</li>
650</ul>
651
Daniel Veillardb6c1e2f2002-02-08 14:52:52 +0000[diff] [blame]652<h3>2.4.14: Feb 8 2002</h3>
653<ul>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]654 <li>Change of License to the <a
Daniel Veillardb6c1e2f2002-02-08 14:52:52 +0000[diff] [blame]655 href="http://www.opensource.org/licenses/mit-license.html">MIT
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]656 License</a> basically for integration in XFree86 codebase, and removing
657 confusion around the previous dual-licensing</li>
Daniel Veillardb6c1e2f2002-02-08 14:52:52 +0000[diff] [blame]658 <li>added Python bindings, beta software but should already be quite
659 complete</li>
660 <li>a large number of fixes and cleanups, especially for all tree
661 manipulations</li>
662 <li>cleanup of the headers, generation of a reference API definition in
663 XML</li>
664</ul>
665
666<h3>2.4.13: Jan 14 2002</h3>
Daniel Veillard744683d2002-01-14 17:30:20 +0000[diff] [blame]667<ul>
668 <li>update of the documentation: John Fleck and Charlie Bozeman</li>
669 <li>cleanup of timing code from Justin Fletcher</li>
670 <li>fixes for Windows and initial thread support on Win32: Igor and Serguei
671 Narojnyi</li>
672 <li>Cygwin patch from Robert Collins</li>
673 <li>added xmlSetEntityReferenceFunc() for Keith Isdale work on xsldbg</li>
674</ul>
675
Daniel Veillardef90ba72001-12-07 14:24:22 +0000[diff] [blame]676<h3>2.4.12: Dec 7 2001</h3>
677<ul>
678 <li>a few bug fixes: thread (Gary Pennington), xmllint (Geert Kloosterman),
679 XML parser (Robin Berjon), XPointer (Danny Jamshy), I/O cleanups
680 (robert)</li>
681 <li>Eric Lavigne contributed project files for MacOS</li>
682 <li>some makefiles cleanups</li>
683</ul>
684
Daniel Veillarda4871052001-11-26 13:19:48 +0000[diff] [blame]685<h3>2.4.11: Nov 26 2001</h3>
686<ul>
687 <li>fixed a couple of errors in the includes, fixed a few bugs, some code
688 cleanups</li>
689 <li>xmllint man pages improvement by Heiko Rupp</li>
690 <li>updated VMS build instructions from John A Fotheringham</li>
691 <li>Windows Makefiles updates from Igor</li>
692</ul>
693
Daniel Veillard43d3f612001-11-10 11:57:23 +0000[diff] [blame]694<h3>2.4.10: Nov 10 2001</h3>
695<ul>
696 <li>URI escaping fix (Joel Young)</li>
697 <li>added xmlGetNodePath() (for paths or XPointers generation)</li>
698 <li>Fixes namespace handling problems when using DTD and validation</li>
699 <li>improvements on xmllint: Morus Walter patches for --format and
700 --encode, Stefan Kost and Heiko Rupp improvements on the --shell</li>
701 <li>fixes for xmlcatalog linking pointed by Weiqi Gao</li>
702 <li>fixes to the HTML parser</li>
703</ul>
704
705<h3>2.4.9: Nov 6 2001</h3>
706<ul>
707 <li>fixes more catalog bugs</li>
708 <li>avoid a compilation problem, improve xmlGetLineNo()</li>
709</ul>
710
Daniel Veillarded421aa2001-11-04 21:22:45 +0000[diff] [blame]711<h3>2.4.8: Nov 4 2001</h3>
712<ul>
713 <li>fixed SGML catalogs broken in previous release, updated xmlcatalog
714 tool</li>
715 <li>fixed a compile errors and some includes troubles.</li>
716</ul>
717
Daniel Veillard52dcab32001-10-30 12:51:17 +0000[diff] [blame]718<h3>2.4.7: Oct 30 2001</h3>
719<ul>
720 <li>exported some debugging interfaces</li>
721 <li>serious rewrite of the catalog code</li>
722 <li>integrated Gary Pennington thread safety patch, added configure option
723 and regression tests</li>
724 <li>removed an HTML parser bug</li>
725 <li>fixed a couple of potentially serious validation bugs</li>
726 <li>integrated the SGML DocBook support in xmllint</li>
727 <li>changed the nanoftp anonymous login passwd</li>
728 <li>some I/O cleanup and a couple of interfaces for Perl wrapper</li>
729 <li>general bug fixes</li>
730 <li>updated xmllint man page by John Fleck</li>
731 <li>some VMS and Windows updates</li>
732</ul>
733
Daniel Veillard60087f32001-10-10 09:45:09 +0000[diff] [blame]734<h3>2.4.6: Oct 10 2001</h3>
735<ul>
Daniel Veillard52dcab32001-10-30 12:51:17 +0000[diff] [blame]736 <li>added an updated man pages by John Fleck</li>
Daniel Veillard60087f32001-10-10 09:45:09 +0000[diff] [blame]737 <li>portability and configure fixes</li>
738 <li>an infinite loop on the HTML parser was removed (William)</li>
739 <li>Windows makefile patches from Igor</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]740 <li>fixed half a dozen bugs reported for libxml or libxslt</li>
Daniel Veillard60087f32001-10-10 09:45:09 +0000[diff] [blame]741 <li>updated xmlcatalog to be able to modify SGML super catalogs</li>
742</ul>
743
Daniel Veillarddadd0872001-09-15 09:21:44 +0000[diff] [blame]744<h3>2.4.5: Sep 14 2001</h3>
745<ul>
746 <li>Remove a few annoying bugs in 2.4.4</li>
747 <li>forces the HTML serializer to output decimal charrefs since some
748 version of Netscape can't handle hexadecimal ones</li>
749</ul>
750
751<h3>1.8.16: Sep 14 2001</h3>
752<ul>
753 <li>maintenance release of the old libxml1 branch, couple of bug and
754 portability fixes</li>
755</ul>
756
Daniel Veillard04382ae2001-09-12 18:51:30 +0000[diff] [blame]757<h3>2.4.4: Sep 12 2001</h3>
758<ul>
759 <li>added --convert to xmlcatalog, bug fixes and cleanups of XML
760 Catalog</li>
761 <li>a few bug fixes and some portability changes</li>
762 <li>some documentation cleanups</li>
763</ul>
764
Daniel Veillard39936902001-08-24 00:49:01 +0000[diff] [blame]765<h3>2.4.3: Aug 23 2001</h3>
766<ul>
767 <li>XML Catalog support see the doc</li>
768 <li>New NaN/Infinity floating point code</li>
769 <li>A few bug fixes</li>
770</ul>
771
772<h3>2.4.2: Aug 15 2001</h3>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]773<ul>
774 <li>adds xmlLineNumbersDefault() to control line number generation</li>
775 <li>lot of bug fixes</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]776 <li>the Microsoft MSC projects files should now be up to date</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]777 <li>inheritance of namespaces from DTD defaulted attributes</li>
778 <li>fixes a serious potential security bug</li>
779 <li>added a --format option to xmllint</li>
780</ul>
781
782<h3>2.4.1: July 24 2001</h3>
783<ul>
784 <li>possibility to keep line numbers in the tree</li>
785 <li>some computation NaN fixes</li>
786 <li>extension of the XPath API</li>
787 <li>cleanup for alpha and ia64 targets</li>
788 <li>patch to allow saving through HTTP PUT or POST</li>
Daniel Veillard09ab7e12001-07-10 15:49:44 +0000[diff] [blame]789</ul>
790
791<h3>2.4.0: July 10 2001</h3>
792<ul>
793 <li>Fixed a few bugs in XPath, validation, and tree handling.</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]794 <li>Fixed XML Base implementation, added a couple of examples to the
Daniel Veillard09ab7e12001-07-10 15:49:44 +0000[diff] [blame]795 regression tests</li>
796 <li>A bit of cleanup</li>
Daniel Veillardab8500d2000-10-15 21:06:19 +0000[diff] [blame]797</ul>
798
Daniel Veillard5b43fde2001-07-05 23:31:40 +0000[diff] [blame]799<h3>2.3.14: July 5 2001</h3>
800<ul>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]801 <li>fixed some entities problems and reduce memory requirement when
802 substituting them</li>
Daniel Veillard5b43fde2001-07-05 23:31:40 +0000[diff] [blame]803 <li>lots of improvements in the XPath queries interpreter can be
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]804 substantially faster</li>
Daniel Veillard5b43fde2001-07-05 23:31:40 +0000[diff] [blame]805 <li>Makefiles and configure cleanups</li>
806 <li>Fixes to XPath variable eval, and compare on empty node set</li>
807 <li>HTML tag closing bug fixed</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]808 <li>Fixed an URI reference computation problem when validating</li>
Daniel Veillard5b43fde2001-07-05 23:31:40 +0000[diff] [blame]809</ul>
810
Daniel Veillard2adbb512001-06-28 16:20:36 +0000[diff] [blame]811<h3>2.3.13: June 28 2001</h3>
812<ul>
813 <li>2.3.12 configure.in was broken as well as the push mode XML parser</li>
814 <li>a few more fixes for compilation on Windows MSC by Yon Derek</li>
815</ul>
816
817<h3>1.8.14: June 28 2001</h3>
818<ul>
819 <li>Zbigniew Chyla gave a patch to use the old XML parser in push mode</li>
820 <li>Small Makefile fix</li>
821</ul>
822
Daniel Veillard11648102001-06-26 16:08:24 +0000[diff] [blame]823<h3>2.3.12: June 26 2001</h3>
824<ul>
825 <li>lots of cleanup</li>
826 <li>a couple of validation fix</li>
827 <li>fixed line number counting</li>
828 <li>fixed serious problems in the XInclude processing</li>
829 <li>added support for UTF8 BOM at beginning of entities</li>
830 <li>fixed a strange gcc optimizer bugs in xpath handling of float, gcc-3.0
831 miscompile uri.c (William), Thomas Leitner provided a fix for the
832 optimizer on Tru64</li>
833 <li>incorporated Yon Derek and Igor Zlatkovic fixes and improvements for
834 compilation on Windows MSC</li>
835 <li>update of libxml-doc.el (Felix Natter)</li>
836 <li>fixed 2 bugs in URI normalization code</li>
837</ul>
838
Daniel Veillarde3c81b52001-06-17 14:50:34 +0000[diff] [blame]839<h3>2.3.11: June 17 2001</h3>
840<ul>
841 <li>updates to trio, Makefiles and configure should fix some portability
842 problems (alpha)</li>
843 <li>fixed some HTML serialization problems (pre, script, and block/inline
844 handling), added encoding aware APIs, cleanup of this code</li>
845 <li>added xmlHasNsProp()</li>
846 <li>implemented a specific PI for encoding support in the DocBook SGML
847 parser</li>
848 <li>some XPath fixes (-Infinity, / as a function parameter and namespaces
849 node selection)</li>
850 <li>fixed a performance problem and an error in the validation code</li>
851 <li>fixed XInclude routine to implement the recursive behaviour</li>
852 <li>fixed xmlFreeNode problem when libxml is included statically twice</li>
853 <li>added --version to xmllint for bug reports</li>
854</ul>
855
Daniel Veillard2e4f1882001-06-01 10:11:57 +0000[diff] [blame]856<h3>2.3.10: June 1 2001</h3>
857<ul>
858 <li>fixed the SGML catalog support</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]859 <li>a number of reported bugs got fixed, in XPath, iconv detection,
860 XInclude processing</li>
Daniel Veillard2e4f1882001-06-01 10:11:57 +0000[diff] [blame]861 <li>XPath string function should now handle unicode correctly</li>
862</ul>
863
Daniel Veillard4623acd2001-05-19 15:13:15 +0000[diff] [blame]864<h3>2.3.9: May 19 2001</h3>
865
866<p>Lots of bugfixes, and added a basic SGML catalog support:</p>
867<ul>
868 <li>HTML push bugfix #54891 and another patch from Jonas Borgström</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]869 <li>some serious speed optimization again</li>
Daniel Veillard4623acd2001-05-19 15:13:15 +0000[diff] [blame]870 <li>some documentation cleanups</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]871 <li>trying to get better linking on Solaris (-R)</li>
Daniel Veillard4623acd2001-05-19 15:13:15 +0000[diff] [blame]872 <li>XPath API cleanup from Thomas Broyer</li>
873 <li>Validation bug fixed #54631, added a patch from Gary Pennington, fixed
874 xmlValidGetValidElements()</li>
875 <li>Added an INSTALL file</li>
876 <li>Attribute removal added to API: #54433</li>
877 <li>added a basic support for SGML catalogs</li>
878 <li>fixed xmlKeepBlanksDefault(0) API</li>
879 <li>bugfix in xmlNodeGetLang()</li>
880 <li>fixed a small configure portability problem</li>
881 <li>fixed an inversion of SYSTEM and PUBLIC identifier in HTML document</li>
882</ul>
883
Daniel Veillarda265af72001-05-14 11:13:58 +0000[diff] [blame]884<h3>1.8.13: May 14 2001</h3>
885<ul>
886 <li>bugfixes release of the old libxml1 branch used by Gnome</li>
887</ul>
888
Daniel Veillard3bbbe6f2001-05-03 11:15:37 +0000[diff] [blame]889<h3>2.3.8: May 3 2001</h3>
890<ul>
891 <li>Integrated an SGML DocBook parser for the Gnome project</li>
892 <li>Fixed a few things in the HTML parser</li>
893 <li>Fixed some XPath bugs raised by XSLT use, tried to fix the floating
894 point portability issue</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]895 <li>Speed improvement (8M/s for SAX, 3M/s for DOM, 1.5M/s for
896 DOM+validation using the XML REC as input and a 700MHz celeron).</li>
Daniel Veillard3bbbe6f2001-05-03 11:15:37 +0000[diff] [blame]897 <li>incorporated more Windows cleanup</li>
898 <li>added xmlSaveFormatFile()</li>
899 <li>fixed problems in copying nodes with entities references (gdome)</li>
900 <li>removed some troubles surrounding the new validation module</li>
901</ul>
902
Daniel Veillarda41123c2001-04-22 19:31:20 +0000[diff] [blame]903<h3>2.3.7: April 22 2001</h3>
904<ul>
905 <li>lots of small bug fixes, corrected XPointer</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]906 <li>Non deterministic content model validation support</li>
Daniel Veillarda41123c2001-04-22 19:31:20 +0000[diff] [blame]907 <li>added xmlDocCopyNode for gdome2</li>
908 <li>revamped the way the HTML parser handles end of tags</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]909 <li>XPath: corrections of namespaces support and number formatting</li>
Daniel Veillarda41123c2001-04-22 19:31:20 +0000[diff] [blame]910 <li>Windows: Igor Zlatkovic patches for MSC compilation</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]911 <li>HTML output fixes from P C Chow and William M. Brack</li>
Daniel Veillarda41123c2001-04-22 19:31:20 +0000[diff] [blame]912 <li>Improved validation speed sensible for DocBook</li>
913 <li>fixed a big bug with ID declared in external parsed entities</li>
914 <li>portability fixes, update of Trio from Bjorn Reese</li>
915</ul>
916
Daniel Veillardafc73112001-04-11 11:51:41 +0000[diff] [blame]917<h3>2.3.6: April 8 2001</h3>
918<ul>
919 <li>Code cleanup using extreme gcc compiler warning options, found and
920 cleared half a dozen potential problem</li>
921 <li>the Eazel team found an XML parser bug</li>
922 <li>cleaned up the user of some of the string formatting function. used the
923 trio library code to provide the one needed when the platform is missing
924 them</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]925 <li>xpath: removed a memory leak and fixed the predicate evaluation
926 problem, extended the testsuite and cleaned up the result. XPointer seems
927 broken ...</li>
Daniel Veillardafc73112001-04-11 11:51:41 +0000[diff] [blame]928</ul>
929
Daniel Veillard56a4cb82001-03-24 17:00:36 +0000[diff] [blame]930<h3>2.3.5: Mar 23 2001</h3>
931<ul>
932 <li>Biggest change is separate parsing and evaluation of XPath expressions,
933 there is some new APIs for this too</li>
934 <li>included a number of bug fixes(XML push parser, 51876, notations,
935 52299)</li>
936 <li>Fixed some portability issues</li>
937</ul>
938
Daniel Veillarde356c282001-03-10 12:32:04 +0000[diff] [blame]939<h3>2.3.4: Mar 10 2001</h3>
940<ul>
941 <li>Fixed bugs #51860 and #51861</li>
942 <li>Added a global variable xmlDefaultBufferSize to allow default buffer
943 size to be application tunable.</li>
944 <li>Some cleanup in the validation code, still a bug left and this part
945 should probably be rewritten to support ambiguous content model :-\</li>
946 <li>Fix a couple of serious bugs introduced or raised by changes in 2.3.3
947 parser</li>
948 <li>Fixed another bug in xmlNodeGetContent()</li>
949 <li>Bjorn fixed XPath node collection and Number formatting</li>
950 <li>Fixed a loop reported in the HTML parsing</li>
951 <li>blank space are reported even if the Dtd content model proves that they
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]952 are formatting spaces, this is for XML conformance</li>
Daniel Veillarde356c282001-03-10 12:32:04 +0000[diff] [blame]953</ul>
954
Daniel Veillardb402c072001-03-01 17:28:58 +0000[diff] [blame]955<h3>2.3.3: Mar 1 2001</h3>
956<ul>
957 <li>small change in XPath for XSLT</li>
958 <li>documentation cleanups</li>
959 <li>fix in validation by Gary Pennington</li>
960 <li>serious parsing performances improvements</li>
961</ul>
962
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]963<h3>2.3.2: Feb 24 2001</h3>
Daniel Veillard71681102001-02-24 17:48:53 +0000[diff] [blame]964<ul>
965 <li>chasing XPath bugs, found a bunch, completed some TODO</li>
966 <li>fixed a Dtd parsing bug</li>
967 <li>fixed a bug in xmlNodeGetContent</li>
968 <li>ID/IDREF support partly rewritten by Gary Pennington</li>
969</ul>
970
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]971<h3>2.3.1: Feb 15 2001</h3>
Daniel Veillard6e6a6cc2001-02-15 15:55:44 +0000[diff] [blame]972<ul>
973 <li>some XPath and HTML bug fixes for XSLT</li>
974 <li>small extension of the hash table interfaces for DOM gdome2
975 implementation</li>
976 <li>A few bug fixes</li>
977</ul>
978
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]979<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]980<ul>
981 <li>Lots of XPath bug fixes</li>
982 <li>Add a mode with Dtd lookup but without validation error reporting for
983 XSLT</li>
984 <li>Add support for text node without escaping (XSLT)</li>
985 <li>bug fixes for xmlCheckFilename</li>
986 <li>validation code bug fixes from Gary Pennington</li>
987 <li>Patch from Paul D. Smith correcting URI path normalization</li>
988 <li>Patch to allow simultaneous install of libxml-devel and
989 libxml2-devel</li>
990 <li>the example Makefile is now fixed</li>
991 <li>added HTML to the RPM packages</li>
992 <li>tree copying bugfixes</li>
993 <li>updates to Windows makefiles</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]994 <li>optimization patch from Bjorn Reese</li>
Daniel Veillard6e6a6cc2001-02-15 15:55:44 +0000[diff] [blame]995</ul>
996
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]997<h3>2.2.11: Jan 4 2001</h3>
Daniel Veillard503b8932001-01-05 06:36:31 +0000[diff] [blame]998<ul>
999 <li>bunch of bug fixes (memory I/O, xpath, ftp/http, ...)</li>
1000 <li>added htmlHandleOmittedElem()</li>
1001 <li>Applied Bjorn Reese's IPV6 first patch</li>
1002 <li>Applied Paul D. Smith patches for validation of XInclude results</li>
Daniel Veillard82687162001-01-22 15:32:01 +0000[diff] [blame]1003 <li>added XPointer xmlns() new scheme support</li>
Daniel Veillard503b8932001-01-05 06:36:31 +0000[diff] [blame]1004</ul>
1005
Daniel Veillard2ddd23d2000-11-25 10:42:19 +0000[diff] [blame]1006<h3>2.2.10: Nov 25 2000</h3>
Daniel Veillard9d343c42000-11-25 10:12:43 +0000[diff] [blame]1007<ul>
1008 <li>Fix the Windows problems of 2.2.8</li>
1009 <li>integrate OpenVMS patches</li>
1010 <li>better handling of some nasty HTML input</li>
1011 <li>Improved the XPointer implementation</li>
1012 <li>integrate a number of provided patches</li>
1013</ul>
1014
Daniel Veillard2ddd23d2000-11-25 10:42:19 +0000[diff] [blame]1015<h3>2.2.9: Nov 25 2000</h3>
1016<ul>
1017 <li>erroneous release :-(</li>
1018</ul>
1019
Daniel Veillard28929b22000-11-13 18:22:49 +0000[diff] [blame]1020<h3>2.2.8: Nov 13 2000</h3>
1021<ul>
1022 <li>First version of <a href="http://www.w3.org/TR/xinclude">XInclude</a>
1023 support</li>
1024 <li>Patch in conditional section handling</li>
1025 <li>updated MS compiler project</li>
1026 <li>fixed some XPath problems</li>
1027 <li>added an URI escaping function</li>
1028 <li>some other bug fixes</li>
1029</ul>
1030
1031<h3>2.2.7: Oct 31 2000</h3>
1032<ul>
1033 <li>added message redirection</li>
1034 <li>XPath improvements (thanks TOM !)</li>
1035 <li>xmlIOParseDTD() added</li>
1036 <li>various small fixes in the HTML, URI, HTTP and XPointer support</li>
1037 <li>some cleanup of the Makefile, autoconf and the distribution content</li>
1038</ul>
1039
Daniel Veillard29a11cc2000-10-25 13:32:39 +0000[diff] [blame]1040<h3>2.2.6: Oct 25 2000:</h3>
1041<ul>
1042 <li>Added an hash table module, migrated a number of internal structure to
1043 those</li>
1044 <li>Fixed a posteriori validation problems</li>
1045 <li>HTTP module cleanups</li>
1046 <li>HTML parser improvements (tag errors, script/style handling, attribute
1047 normalization)</li>
1048 <li>coalescing of adjacent text nodes</li>
1049 <li>couple of XPath bug fixes, exported the internal API</li>
1050</ul>
1051
Daniel Veillardab8500d2000-10-15 21:06:19 +0000[diff] [blame]1052<h3>2.2.5: Oct 15 2000:</h3>
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000[diff] [blame]1053<ul>
Daniel Veillard189446d2000-10-13 10:23:06 +0000[diff] [blame]1054 <li>XPointer implementation and testsuite</li>
1055 <li>Lot of XPath fixes, added variable and functions registration, more
1056 tests</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]1057 <li>Portability fixes, lots of enhancements toward an easy Windows build
1058 and release</li>
Daniel Veillard189446d2000-10-13 10:23:06 +0000[diff] [blame]1059 <li>Late validation fixes</li>
1060 <li>Integrated a lot of contributed patches</li>
1061 <li>added memory management docs</li>
Daniel Veillardab8500d2000-10-15 21:06:19 +0000[diff] [blame]1062 <li>a performance problem when using large buffer seems fixed</li>
Daniel Veillard189446d2000-10-13 10:23:06 +0000[diff] [blame]1063</ul>
1064
1065<h3>2.2.4: Oct 1 2000:</h3>
1066<ul>
1067 <li>main XPath problem fixed</li>
1068 <li>Integrated portability patches for Windows</li>
1069 <li>Serious bug fixes on the URI and HTML code</li>
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]1070</ul>
1071
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]1072<h3>2.2.3: Sep 17 2000</h3>
1073<ul>
1074 <li>bug fixes</li>
1075 <li>cleanup of entity handling code</li>
1076 <li>overall review of all loops in the parsers, all sprintf usage has been
1077 checked too</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1078 <li>Far better handling of larges Dtd. Validating against DocBook XML Dtd
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]1079 works smoothly now.</li>
1080</ul>
1081
1082<h3>1.8.10: Sep 6 2000</h3>
1083<ul>
1084 <li>bug fix release for some Gnome projects</li>
1085</ul>
1086
1087<h3>2.2.2: August 12 2000</h3>
Daniel Veillard786d7c82000-08-12 23:38:57 +0000[diff] [blame]1088<ul>
1089 <li>mostly bug fixes</li>
Daniel Veillardec78c0f2000-08-25 10:25:23 +0000[diff] [blame]1090 <li>started adding routines to access xml parser context options</li>
Daniel Veillard786d7c82000-08-12 23:38:57 +0000[diff] [blame]1091</ul>
1092
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]1093<h3>2.2.1: July 21 2000</h3>
Daniel Veillarda2679fa2000-07-22 02:38:15 +0000[diff] [blame]1094<ul>
1095 <li>a purely bug fixes release</li>
1096 <li>fixed an encoding support problem when parsing from a memory block</li>
1097 <li>fixed a DOCTYPE parsing problem</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]1098 <li>removed a bug in the function allowing to override the memory
1099 allocation routines</li>
Daniel Veillarda2679fa2000-07-22 02:38:15 +0000[diff] [blame]1100</ul>
1101
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]1102<h3>2.2.0: July 14 2000</h3>
Daniel Veillard94e90602000-07-17 14:38:19 +0000[diff] [blame]1103<ul>
1104 <li>applied a lot of portability fixes</li>
1105 <li>better encoding support/cleanup and saving (content is now always
1106 encoded in UTF-8)</li>
1107 <li>the HTML parser now correctly handles encodings</li>
1108 <li>added xmlHasProp()</li>
1109 <li>fixed a serious problem with &amp;#38;</li>
1110 <li>propagated the fix to FTP client</li>
1111 <li>cleanup, bugfixes, etc ...</li>
1112 <li>Added a page about <a href="encoding.html">libxml Internationalization
1113 support</a></li>
1114</ul>
1115
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1116<h3>1.8.9: July 9 2000</h3>
1117<ul>
1118 <li>fixed the spec the RPMs should be better</li>
1119 <li>fixed a serious bug in the FTP implementation, released 1.8.9 to solve
1120 rpmfind users problem</li>
1121</ul>
1122
Daniel Veillard6388e172000-07-03 16:07:19 +0000[diff] [blame]1123<h3>2.1.1: July 1 2000</h3>
1124<ul>
1125 <li>fixes a couple of bugs in the 2.1.0 packaging</li>
1126 <li>improvements on the HTML parser</li>
1127</ul>
1128
Daniel Veillard3f6f7f62000-06-30 17:58:25 +0000[diff] [blame]1129<h3>2.1.0 and 1.8.8: June 29 2000</h3>
1130<ul>
Daniel Veillardc0801af2002-05-28 16:28:42 +0000[diff] [blame^]1131 <li>1.8.8 is mostly a commodity package for upgrading to libxml2 according
1132 to <a href="upgrade.html">new instructions</a>. It fixes a nasty problem
Daniel Veillard3f6f7f62000-06-30 17:58:25 +0000[diff] [blame]1133 about &amp;#38; charref parsing</li>
1134 <li>2.1.0 also ease the upgrade from libxml v1 to the recent version. it
1135 also contains numerous fixes and enhancements:
1136 <ul>
1137 <li>added xmlStopParser() to stop parsing</li>
1138 <li>improved a lot parsing speed when there is large CDATA blocs</li>
1139 <li>includes XPath patches provided by Picdar Technology</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1140 <li>tried to fix as much as possible DTD validation and namespace
Daniel Veillard3f6f7f62000-06-30 17:58:25 +0000[diff] [blame]1141 related problems</li>
1142 <li>output to a given encoding has been added/tested</li>
1143 <li>lot of various fixes</li>
1144 </ul>
1145 </li>
1146</ul>
1147
Daniel Veillarde0aed302000-04-16 08:52:20 +0000[diff] [blame]1148<h3>2.0.0: Apr 12 2000</h3>
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]1149<ul>
1150 <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]1151 idea to check the 1.x to 2.x upgrade instructions. NOTE: while initially
1152 scheduled for Apr 3 the release occurred only on Apr 12 due to massive
Daniel Veillarde0aed302000-04-16 08:52:20 +0000[diff] [blame]1153 workload.</li>
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]1154 <li>The include are now located under $prefix/include/libxml (instead of
Daniel Veillarde0aed302000-04-16 08:52:20 +0000[diff] [blame]1155 $prefix/include/gnome-xml), they also are referenced by
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1156 <pre>#include &lt;libxml/xxx.h&gt;</pre>
Daniel Veillarde0aed302000-04-16 08:52:20 +0000[diff] [blame]1157 <p>instead of</p>
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]1158 <pre>#include "xxx.h"</pre>
1159 </li>
Daniel Veillard8f621982000-03-20 13:07:15 +0000[diff] [blame]1160 <li>a new URI module for parsing URIs and following strictly RFC 2396</li>
1161 <li>the memory allocation routines used by libxml can now be overloaded
1162 dynamically by using xmlMemSetup()</li>
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]1163 <li>The previously CVS only tool tester has been renamed
1164 <strong>xmllint</strong> and is now installed as part of the libxml2
1165 package</li>
Daniel Veillarde0aed302000-04-16 08:52:20 +0000[diff] [blame]1166 <li>The I/O interface has been revamped. There is now ways to plug in
1167 specific I/O modules, either at the URI scheme detection level using
1168 xmlRegisterInputCallbacks() or by passing I/O functions when creating a
1169 parser context using xmlCreateIOParserCtxt()</li>
1170 <li>there is a C preprocessor macro LIBXML_VERSION providing the version
1171 number of the libxml module in use</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]1172 <li>a number of optional features of libxml can now be excluded at
1173 configure time (FTP/HTTP/HTML/XPath/Debug)</li>
Daniel Veillardedfb29b2000-03-14 19:59:05 +0000[diff] [blame]1174</ul>
1175
1176<h3>2.0.0beta: Mar 14 2000</h3>
1177<ul>
1178 <li>This is a first Beta release of libxml version 2</li>
Daniel Veillarde356c282001-03-10 12:32:04 +0000[diff] [blame]1179 <li>It's available only from<a href="ftp://xmlsoft.org/">xmlsoft.org
1180 FTP</a>, it's packaged as libxml2-2.0.0beta and available as tar and
1181 RPMs</li>
Daniel Veillardedfb29b2000-03-14 19:59:05 +0000[diff] [blame]1182 <li>This version is now the head in the Gnome CVS base, the old one is
1183 available under the tag LIB_XML_1_X</li>
Daniel Veillardc0801af2002-05-28 16:28:42 +0000[diff] [blame^]1184 <li>This includes a very large set of changes. From a programmatic point
1185 of view applications should not have to be modified too much, check the
1186 <a href="upgrade.html">upgrade page</a></li>
Daniel Veillardedfb29b2000-03-14 19:59:05 +0000[diff] [blame]1187 <li>Some interfaces may changes (especially a bit about encoding).</li>
1188 <li>the updates includes:
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]1189 <ul>
Daniel Veillardedfb29b2000-03-14 19:59:05 +0000[diff] [blame]1190 <li>fix I18N support. ISO-Latin-x/UTF-8/UTF-16 (nearly) seems correctly
1191 handled now</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1192 <li>Better handling of entities, especially well-formedness checking
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]1193 and proper PEref extensions in external subsets</li>
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]1194 <li>DTD conditional sections</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1195 <li>Validation now correctly handle entities content</li>
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]1196 <li><a href="http://rpmfind.net/tools/gdome/messages/0039.html">change
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1197 structures to accommodate DOM</a></li>
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]1198 </ul>
1199 </li>
Daniel Veillardedfb29b2000-03-14 19:59:05 +0000[diff] [blame]1200 <li>Serious progress were made toward compliance, <a
1201 href="conf/result.html">here are the result of the test</a> against the
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1202 OASIS testsuite (except the Japanese tests since I don't support that
Daniel Veillardedfb29b2000-03-14 19:59:05 +0000[diff] [blame]1203 encoding yet). This URL is rebuilt every couple of hours using the CVS
1204 head version.</li>
Daniel Veillarde41f2b72000-01-30 20:00:07 +0000[diff] [blame]1205</ul>
1206
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1207<h3>1.8.7: Mar 6 2000</h3>
1208<ul>
1209 <li>This is a bug fix release:</li>
1210 <li>It is possible to disable the ignorable blanks heuristic used by
1211 libxml-1.x, a new function xmlKeepBlanksDefault(0) will allow this. Note
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]1212 that for adherence to XML spec, this behaviour will be disabled by
1213 default in 2.x . The same function will allow to keep compatibility for
1214 old code.</li>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1215 <li>Blanks in &lt;a&gt; &lt;/a&gt; constructs are not ignored anymore,
1216 avoiding heuristic is really the Right Way :-\</li>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1217 <li>The unchecked use of snprintf which was breaking libxml-1.8.6
1218 compilation on some platforms has been fixed</li>
1219 <li>nanoftp.c nanohttp.c: Fixed '#' and '?' stripping when processing
1220 URIs</li>
1221</ul>
1222
Daniel Veillarde41f2b72000-01-30 20:00:07 +0000[diff] [blame]1223<h3>1.8.6: Jan 31 2000</h3>
1224<ul>
1225 <li>added a nanoFTP transport module, debugged until the new version of <a
1226 href="http://rpmfind.net/linux/rpm2html/rpmfind.html">rpmfind</a> can use
1227 it without troubles</li>
Daniel Veillardda07c342000-01-25 18:31:22 +0000[diff] [blame]1228</ul>
1229
1230<h3>1.8.5: Jan 21 2000</h3>
1231<ul>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]1232 <li>adding APIs to parse a well balanced chunk of XML (production <a
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]1233 href="http://www.w3.org/TR/REC-xml#NT-content">[43] content</a> of the
1234 XML spec)</li>
Daniel Veillard461a66c2000-01-18 18:01:01 +0000[diff] [blame]1235 <li>fixed a hideous bug in xmlGetProp pointed by Rune.Djurhuus@fast.no</li>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1236 <li>Jody Goldberg &lt;jgoldberg@home.com&gt; provided another patch trying
1237 to solve the zlib checks problems</li>
Daniel Veillard461a66c2000-01-18 18:01:01 +0000[diff] [blame]1238 <li>The current state in gnome CVS base is expected to ship as 1.8.5 with
1239 gnumeric soon</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]1240</ul>
1241
1242<h3>1.8.4: Jan 13 2000</h3>
1243<ul>
1244 <li>bug fixes, reintroduced xmlNewGlobalNs(), fixed xmlNewNs()</li>
1245 <li>all exit() call should have been removed from libxml</li>
1246 <li>fixed a problem with INCLUDE_WINSOCK on WIN32 platform</li>
1247 <li>added newDocFragment()</li>
Daniel Veillardf84f71f2000-01-05 19:54:23 +0000[diff] [blame]1248</ul>
1249
1250<h3>1.8.3: Jan 5 2000</h3>
1251<ul>
1252 <li>a Push interface for the XML and HTML parsers</li>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1253 <li>a shell-like interface to the document tree (try tester --shell :-)</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1254 <li>lots of bug fixes and improvement added over XMas holidays</li>
Daniel Veillard437b87b2000-01-03 17:30:46 +0000[diff] [blame]1255 <li>fixed the DTD parsing code to work with the xhtml DTD</li>
Daniel Veillardf84f71f2000-01-05 19:54:23 +0000[diff] [blame]1256 <li>added xmlRemoveProp(), xmlRemoveID() and xmlRemoveRef()</li>
1257 <li>Fixed bugs in xmlNewNs()</li>
Daniel Veillard437b87b2000-01-03 17:30:46 +0000[diff] [blame]1258 <li>External entity loading code has been revamped, now it uses
Daniel Veillardf84f71f2000-01-05 19:54:23 +0000[diff] [blame]1259 xmlLoadExternalEntity(), some fix on entities processing were added</li>
Daniel Veillard437b87b2000-01-03 17:30:46 +0000[diff] [blame]1260 <li>cleaned up WIN32 includes of socket stuff</li>
Daniel Veillard5cb5ab81999-12-21 15:35:29 +0000[diff] [blame]1261</ul>
1262
1263<h3>1.8.2: Dec 21 1999</h3>
1264<ul>
Daniel Veillardb24054a1999-12-18 15:32:46 +0000[diff] [blame]1265 <li>I got another problem with includes and C++, I hope this issue is fixed
1266 for good this time</li>
Daniel Veillard5cb5ab81999-12-21 15:35:29 +0000[diff] [blame]1267 <li>Added a few tree modification functions: xmlReplaceNode,
1268 xmlAddPrevSibling, xmlAddNextSibling, xmlNodeSetName and
1269 xmlDocSetRootElement</li>
1270 <li>Tried to improve the HTML output with help from <a
1271 href="mailto:clahey@umich.edu">Chris Lahey</a></li>
Daniel Veillarde4e51311999-12-18 15:32:46 +0000[diff] [blame]1272</ul>
Daniel Veillardb24054a1999-12-18 15:32:46 +0000[diff] [blame]1273
Daniel Veillarde4e51311999-12-18 15:32:46 +0000[diff] [blame]1274<h3>1.8.1: Dec 18 1999</h3>
1275<ul>
1276 <li>various patches to avoid troubles when using libxml with C++ compilers
1277 the "namespace" keyword and C escaping in include files</li>
1278 <li>a problem in one of the core macros IS_CHAR was corrected</li>
1279 <li>fixed a bug introduced in 1.8.0 breaking default namespace processing,
1280 and more specifically the Dia application</li>
Daniel Veillard944b5ff1999-12-15 19:08:24 +0000[diff] [blame]1281 <li>fixed a posteriori validation (validation after parsing, or by using a
1282 Dtd not specified in the original document)</li>
Daniel Veillardb24054a1999-12-18 15:32:46 +0000[diff] [blame]1283 <li>fixed a bug in</li>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]1284</ul>
1285
1286<h3>1.8.0: Dec 12 1999</h3>
1287<ul>
1288 <li>cleanup, especially memory wise</li>
1289 <li>the parser should be more reliable, especially the HTML one, it should
1290 not crash, whatever the input !</li>
1291 <li>Integrated various patches, especially a speedup improvement for large
1292 dataset from <a href="mailto:cnygard@bellatlantic.net">Carl Nygard</a>,
1293 configure with --with-buffers to enable them.</li>
1294 <li>attribute normalization, oops should have been added long ago !</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1295 <li>attributes defaulted from DTDs should be available, xmlSetProp() now
1296 does entities escaping by default.</li>
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000[diff] [blame]1297</ul>
Daniel Veillard35008381999-10-25 13:15:52 +0000[diff] [blame]1298
1299<h3>1.7.4: Oct 25 1999</h3>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]1300<ul>
Daniel Veillard35008381999-10-25 13:15:52 +0000[diff] [blame]1301 <li>Lots of HTML improvement</li>
1302 <li>Fixed some errors when saving both XML and HTML</li>
1303 <li>More examples, the regression tests should now look clean</li>
1304 <li>Fixed a bug with contiguous charref</li>
1305</ul>
1306
1307<h3>1.7.3: Sep 29 1999</h3>
1308<ul>
1309 <li>portability problems fixed</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1310 <li>snprintf was used unconditionally, leading to link problems on system
Daniel Veillard35008381999-10-25 13:15:52 +0000[diff] [blame]1311 were it's not available, fixed</li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]1312</ul>
1313
1314<h3>1.7.1: Sep 24 1999</h3>
1315<ul>
1316 <li>The basic type for strings manipulated by libxml has been renamed in
1317 1.7.1 from <strong>CHAR</strong> to <strong>xmlChar</strong>. The reason
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]1318 is that CHAR was conflicting with a predefined type on Windows. However
1319 on non WIN32 environment, compatibility is provided by the way of a
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]1320 <strong>#define </strong>.</li>
1321 <li>Changed another error : the use of a structure field called errno, and
1322 leading to troubles on platforms where it's a macro</li>
1323</ul>
1324
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1325<h3>1.7.0: Sep 23 1999</h3>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]1326<ul>
1327 <li>Added the ability to fetch remote DTD or parsed entities, see the <a
Daniel Veillard9cb5ff42001-01-29 08:22:21 +0000[diff] [blame]1328 href="html/libxml-nanohttp.html">nanohttp</a> module.</li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]1329 <li>Added an errno to report errors by another mean than a simple printf
1330 like callback</li>
1331 <li>Finished ID/IDREF support and checking when validation</li>
1332 <li>Serious memory leaks fixed (there is now a <a
Daniel Veillard9cb5ff42001-01-29 08:22:21 +0000[diff] [blame]1333 href="html/libxml-xmlmemory.html">memory wrapper</a> module)</li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]1334 <li>Improvement of <a href="http://www.w3.org/TR/xpath">XPath</a>
1335 implementation</li>
1336 <li>Added an HTML parser front-end</li>
1337</ul>
1338
1339<h2><a name="XML">XML</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1340
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]1341<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]1342markup-based structured documents. Here is <a name="example">an example XML
1343document</a>:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1344<pre>&lt;?xml version="1.0"?&gt;
1345&lt;EXAMPLE prop1="gnome is great" prop2="&amp;amp; linux too"&gt;
1346 &lt;head&gt;
1347 &lt;title&gt;Welcome to Gnome&lt;/title&gt;
1348 &lt;/head&gt;
1349 &lt;chapter&gt;
1350 &lt;title&gt;The Linux adventure&lt;/title&gt;
1351 &lt;p&gt;bla bla bla ...&lt;/p&gt;
1352 &lt;image href="linus.gif"/&gt;
1353 &lt;p&gt;...&lt;/p&gt;
1354 &lt;/chapter&gt;
1355&lt;/EXAMPLE&gt;</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1356
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]1357<p>The first line specifies that it's an XML document and gives useful
1358information about its encoding. Then the document is a text format whose
1359structure is specified by tags between brackets. <strong>Each tag opened has
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1360to be closed</strong>. XML is pedantic about this. However, if a tag is empty
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]1361(no content), a single tag can serve as both the opening and closing tag if
1362it ends with <code>/&gt;</code> rather than with <code>&gt;</code>. Note
1363that, for example, the image tag has no content (just an attribute) and is
1364closed by ending the tag with <code>/&gt;</code>.</p>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]1365
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1366<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]1367structured document maintenance (where it follows the steps of SGML) to
1368simple data encoding mechanisms like configuration file formatting (glade),
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1369spreadsheets (gnumeric), or even shorter lived documents such as WebDAV where
1370it is used to encode remote calls between a client and a server.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1371
Daniel Veillard82687162001-01-22 15:32:01 +0000[diff] [blame]1372<h2><a name="XSLT">XSLT</a></h2>
1373
Daniel Veillard6e6a6cc2001-02-15 15:55:44 +0000[diff] [blame]1374<p>Check <a href="http://xmlsoft.org/XSLT">the separate libxslt page</a></p>
1375
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]1376<p><a href="http://www.w3.org/TR/xslt">XSL Transformations</a>, is a
1377language for transforming XML documents into other XML documents (or
1378HTML/textual output).</p>
Daniel Veillard82687162001-01-22 15:32:01 +0000[diff] [blame]1379
1380<p>A separate library called libxslt is being built on top of libxml2. This
1381module "libxslt" can be found in the Gnome CVS base too.</p>
1382
Daniel Veillard383b1472001-01-23 11:39:52 +0000[diff] [blame]1383<p>You can check the <a
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]1384href="http://cvs.gnome.org/lxr/source/libxslt/FEATURES">features</a>
1385supported and the progresses on the <a
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1386href="http://cvs.gnome.org/lxr/source/libxslt/ChangeLog"
1387name="Changelog">Changelog</a></p>
1388
1389<h2><a name="Python">Python and bindings</a></h2>
1390
1391<p>There is a number of language bindings and wrappers available for libxml2,
1392the list below is not exhaustive. Please contact the <a
1393href="http://mail.gnome.org/mailman/listinfo/xml-bindings">xml-bindings@gnome.org</a>
1394(<a href="http://mail.gnome.org/archives/xml-bindings/">archives</a>) in
1395order to get updates to this list or to discuss the specific topic of libxml2
1396or libxslt wrappers or bindings:</p>
1397<ul>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]1398 <li><a href="mailto:ari@lusis.org">Ari Johnson</a> provides a C++ wrapper
1399 for libxml:<br>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1400 Website: <a
1401 href="http://lusis.org/~ari/xml++/">http://lusis.org/~ari/xml++/</a><br>
1402 Download: <a
1403 href="http://lusis.org/~ari/xml++/libxml++.tar.gz">http://lusis.org/~ari/xml++/libxml++.tar.gz</a></li>
1404 <li>There is another <a href="http://libgdome-cpp.berlios.de/">C++ wrapper
1405 based on the gdome2 </a>bindings maintained by Tobias Peters.</li>
Daniel Veillard9b6fd302002-05-13 12:06:47 +0000[diff] [blame]1406 <li>and a third C++ wrapper by Peter Jones &lt;pjones@pmade.org&gt;
1407 <p>Website: <a
1408 href="http://pmade.org/pjones/software/xmlwrapp/">http://pmade.org/pjones/software/xmlwrapp/</a></p>
1409 </li>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1410 <li><a
1411 href="http://mail.gnome.org/archives/xml/2001-March/msg00014.html">Matt
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1412 Sergeant</a> developed <a
1413 href="http://axkit.org/download/">XML::LibXSLT</a>, a Perl wrapper for
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]1414 libxml2/libxslt as part of the <a href="http://axkit.com/">AxKit XML
1415 application server</a></li>
1416 <li><a href="mailto:dkuhlman@cutter.rexx.com">Dave Kuhlman</a> provides and
1417 earlier version of the libxml/libxslt <a
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1418 href="http://www.rexx.com/~dkuhlman">wrappers for Python</a></li>
1419 <li>Petr Kozelka provides <a
1420 href="http://sourceforge.net/projects/libxml2-pas">Pascal units to glue
1421 libxml2</a> with Kylix, Delphi and other Pascal compilers</li>
Daniel Veillardb2fb8ed2002-04-01 09:33:12 +0000[diff] [blame]1422 <li>Uwe Fechner also provides <a
1423 href="http://sourceforge.net/projects/idom2-pas/">idom2</a>, a DOM2
Daniel Veillard75794822002-04-11 16:24:32 +0000[diff] [blame]1424 implementation for Kylix2/D5/D6 from Borland</li>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1425 <li>Wai-Sun "Squidster" Chia provides <a
1426 href="http://www.rubycolor.org/arc/redist/">bindings for Ruby</a> and
1427 libxml2 bindings are also available in Ruby through the <a
1428 href="http://libgdome-ruby.berlios.de/">libgdome-ruby</a> module
1429 maintained by Tobias Peters.</li>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]1430 <li>Steve Ball and contributors maintains <a
1431 href="http://tclxml.sourceforge.net/">libxml2 and libxslt bindings for
1432 Tcl</a></li>
1433 <li>There is support for libxml2 in the DOM module of PHP.</li>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1434</ul>
1435
Daniel Veillardc0801af2002-05-28 16:28:42 +0000[diff] [blame^]1436<p>The distribution includes a set of Python bindings, which are guaranteed
1437to be maintained as part of the library in the future, though the Python
Daniel Veillard0b79dfe2002-02-23 13:02:31 +0000[diff] [blame]1438interface have not yet reached the maturity of the C API.</p>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]1439
1440<p>To install the Python bindings there are 2 options:</p>
Daniel Veillard0b79dfe2002-02-23 13:02:31 +0000[diff] [blame]1441<ul>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]1442 <li>If you use an RPM based distribution, simply install the <a
1443 href="http://rpmfind.net/linux/rpm2html/search.php?query=libxml2-python">libxml2-python
1444 RPM</a> (and if needed the <a
1445 href="http://rpmfind.net/linux/rpm2html/search.php?query=libxslt-python">libxslt-python
1446 RPM</a>).</li>
1447 <li>Otherwise use the <a href="ftp://xmlsoft.org/python/">libxml2-python
1448 module distribution</a> corresponding to your installed version of
1449 libxml2 and libxslt. Note that to install it you will need both libxml2
1450 and libxslt installed and run "python setup.py build install" in the
1451 module tree.</li>
Daniel Veillard0b79dfe2002-02-23 13:02:31 +0000[diff] [blame]1452</ul>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]1453
1454<p>The distribution includes a set of examples and regression tests for the
1455python bindings in the <code>python/tests</code> directory. Here are some
1456excepts from those tests:</p>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1457
1458<h3>tst.py:</h3>
1459
1460<p>This is a basic test of the file interface and DOM navigation:</p>
1461<pre>import libxml2
1462
1463doc = libxml2.parseFile("tst.xml")
1464if doc.name != "tst.xml":
1465 print "doc.name failed"
1466 sys.exit(1)
1467root = doc.children
1468if root.name != "doc":
1469 print "root.name failed"
1470 sys.exit(1)
1471child = root.children
1472if child.name != "foo":
1473 print "child.name failed"
1474 sys.exit(1)
1475doc.freeDoc()</pre>
1476
1477<p>The Python module is called libxml2, parseFile is the equivalent of
1478xmlParseFile (most of the bindings are automatically generated, and the xml
1479prefix is removed and the casing convention are kept). All node seen at the
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1480binding level share the same subset of accessors:</p>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1481<ul>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]1482 <li><code>name</code> : returns the node name</li>
Daniel Veillardc0801af2002-05-28 16:28:42 +0000[diff] [blame^]1483 <li><code>type</code> : returns a string indicating the node type</li>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]1484 <li><code>content</code> : returns the content of the node, it is based on
1485 xmlNodeGetContent() and hence is recursive.</li>
1486 <li><code>parent</code> , <code>children</code>, <code>last</code>,
1487 <code>next</code>, <code>prev</code>, <code>doc</code>,
1488 <code>properties</code>: pointing to the associated element in the tree,
1489 those may return None in case no such link exists.</li>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1490</ul>
1491
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1492<p>Also note the need to explicitly deallocate documents with freeDoc() .
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1493Reference counting for libxml2 trees would need quite a lot of work to
1494function properly, and rather than risk memory leaks if not implemented
1495correctly it sounds safer to have an explicit function to free a tree. The
1496wrapper python objects like doc, root or child are them automatically garbage
1497collected.</p>
1498
1499<h3>validate.py:</h3>
1500
1501<p>This test check the validation interfaces and redirection of error
1502messages:</p>
1503<pre>import libxml2
1504
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1505#deactivate error messages from the validation
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1506def noerr(ctx, str):
1507 pass
1508
1509libxml2.registerErrorHandler(noerr, None)
1510
1511ctxt = libxml2.createFileParserCtxt("invalid.xml")
1512ctxt.validate(1)
1513ctxt.parseDocument()
1514doc = ctxt.doc()
1515valid = ctxt.isValid()
1516doc.freeDoc()
1517if valid != 0:
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1518 print "validity check failed"</pre>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1519
1520<p>The first thing to notice is the call to registerErrorHandler(), it
1521defines a new error handler global to the library. It is used to avoid seeing
1522the error messages when trying to validate the invalid document.</p>
1523
1524<p>The main interest of that test is the creation of a parser context with
1525createFileParserCtxt() and how the behaviour can be changed before calling
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1526parseDocument() . Similarly the informations resulting from the parsing phase
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1527are also available using context methods.</p>
1528
1529<p>Contexts like nodes are defined as class and the libxml2 wrappers maps the
1530C function interfaces in terms of objects method as much as possible. The
1531best to get a complete view of what methods are supported is to look at the
1532libxml2.py module containing all the wrappers.</p>
1533
1534<h3>push.py:</h3>
1535
1536<p>This test show how to activate the push parser interface:</p>
1537<pre>import libxml2
1538
1539ctxt = libxml2.createPushParser(None, "&lt;foo", 4, "test.xml")
1540ctxt.parseChunk("/&gt;", 2, 1)
1541doc = ctxt.doc()
1542
1543doc.freeDoc()</pre>
1544
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1545<p>The context is created with a special call based on the
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1546xmlCreatePushParser() from the C library. The first argument is an optional
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1547SAX callback object, then the initial set of data, the length and the name of
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1548the resource in case URI-References need to be computed by the parser.</p>
1549
1550<p>Then the data are pushed using the parseChunk() method, the last call
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1551setting the third argument terminate to 1.</p>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1552
1553<h3>pushSAX.py:</h3>
1554
1555<p>this test show the use of the event based parsing interfaces. In this case
1556the parser does not build a document, but provides callback information as
1557the parser makes progresses analyzing the data being provided:</p>
1558<pre>import libxml2
1559log = ""
1560
1561class callback:
1562 def startDocument(self):
1563 global log
1564 log = log + "startDocument:"
1565
1566 def endDocument(self):
1567 global log
1568 log = log + "endDocument:"
1569
1570 def startElement(self, tag, attrs):
1571 global log
1572 log = log + "startElement %s %s:" % (tag, attrs)
1573
1574 def endElement(self, tag):
1575 global log
1576 log = log + "endElement %s:" % (tag)
1577
1578 def characters(self, data):
1579 global log
1580 log = log + "characters: %s:" % (data)
1581
1582 def warning(self, msg):
1583 global log
1584 log = log + "warning: %s:" % (msg)
1585
1586 def error(self, msg):
1587 global log
1588 log = log + "error: %s:" % (msg)
1589
1590 def fatalError(self, msg):
1591 global log
1592 log = log + "fatalError: %s:" % (msg)
1593
1594handler = callback()
1595
1596ctxt = libxml2.createPushParser(handler, "&lt;foo", 4, "test.xml")
1597chunk = " url='tst'&gt;b"
1598ctxt.parseChunk(chunk, len(chunk), 0)
1599chunk = "ar&lt;/foo&gt;"
1600ctxt.parseChunk(chunk, len(chunk), 1)
1601
Daniel Veillardfcbfa2d2002-02-21 17:54:27 +0000[diff] [blame]1602reference = "startDocument:startElement foo {'url': 'tst'}:" + \
1603 "characters: bar:endElement foo:endDocument:"
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1604if log != reference:
1605 print "Error got: %s" % log
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1606 print "Expected: %s" % reference</pre>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1607
1608<p>The key object in that test is the handler, it provides a number of entry
1609points which can be called by the parser as it makes progresses to indicate
1610the information set obtained. The full set of callback is larger than what
1611the callback class in that specific example implements (see the SAX
1612definition for a complete list). The wrapper will only call those supplied by
1613the object when activated. The startElement receives the names of the element
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1614and a dictionary containing the attributes carried by this element.</p>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1615
1616<p>Also note that the reference string generated from the callback shows a
1617single character call even though the string "bar" is passed to the parser
1618from 2 different call to parseChunk()</p>
1619
1620<h3>xpath.py:</h3>
1621
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1622<p>This is a basic test of XPath wrappers support</p>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1623<pre>import libxml2
1624
1625doc = libxml2.parseFile("tst.xml")
1626ctxt = doc.xpathNewContext()
1627res = ctxt.xpathEval("//*")
1628if len(res) != 2:
1629 print "xpath query: wrong node set size"
1630 sys.exit(1)
1631if res[0].name != "doc" or res[1].name != "foo":
1632 print "xpath query: wrong node set value"
1633 sys.exit(1)
1634doc.freeDoc()
1635ctxt.xpathFreeContext()</pre>
1636
1637<p>This test parses a file, then create an XPath context to evaluate XPath
1638expression on it. The xpathEval() method execute an XPath query and returns
1639the result mapped in a Python way. String and numbers are natively converted,
1640and node sets are returned as a tuple of libxml2 Python nodes wrappers. Like
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1641the document, the XPath context need to be freed explicitly, also not that
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1642the result of the XPath query may point back to the document tree and hence
1643the document must be freed after the result of the query is used.</p>
1644
1645<h3>xpathext.py:</h3>
1646
1647<p>This test shows how to extend the XPath engine with functions written in
1648python:</p>
1649<pre>import libxml2
1650
1651def foo(ctx, x):
1652 return x + 1
1653
1654doc = libxml2.parseFile("tst.xml")
1655ctxt = doc.xpathNewContext()
1656libxml2.registerXPathFunction(ctxt._o, "foo", None, foo)
1657res = ctxt.xpathEval("foo(1)")
1658if res != 2:
1659 print "xpath extension failure"
1660doc.freeDoc()
1661ctxt.xpathFreeContext()</pre>
1662
1663<p>Note how the extension function is registered with the context (but that
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1664part is not yet finalized, this may change slightly in the future).</p>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1665
1666<h3>tstxpath.py:</h3>
1667
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1668<p>This test is similar to the previous one but shows how the extension
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1669function can access the XPath evaluation context:</p>
1670<pre>def foo(ctx, x):
1671 global called
1672
1673 #
1674 # test that access to the XPath evaluation contexts
1675 #
1676 pctxt = libxml2.xpathParserContext(_obj=ctx)
1677 ctxt = pctxt.context()
1678 called = ctxt.function()
1679 return x + 1</pre>
1680
1681<p>All the interfaces around the XPath parser(or rather evaluation) context
1682are not finalized, but it should be sufficient to do contextual work at the
1683evaluation point.</p>
1684
1685<h3>Memory debugging:</h3>
1686
1687<p>last but not least, all tests starts with the following prologue:</p>
1688<pre>#memory debug specific
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]1689libxml2.debugMemory(1)</pre>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1690
1691<p>and ends with the following epilogue:</p>
1692<pre>#memory debug specific
1693libxml2.cleanupParser()
1694if libxml2.debugMemory(1) == 0:
1695 print "OK"
1696else:
1697 print "Memory leak %d bytes" % (libxml2.debugMemory(1))
1698 libxml2.dumpMemory()</pre>
1699
1700<p>Those activate the memory debugging interface of libxml2 where all
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1701allocated block in the library are tracked. The prologue then cleans up the
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1702library state and checks that all allocated memory has been freed. If not it
1703calls dumpMemory() which saves that list in a <code>.memdump</code> file.</p>
Daniel Veillard82687162001-01-22 15:32:01 +0000[diff] [blame]1704
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]1705<h2><a name="architecture">libxml architecture</a></h2>
Daniel Veillard4540be42000-08-19 16:40:28 +0000[diff] [blame]1706
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]1707<p>Libxml is made of multiple components; some of them are optional, and most
1708of the block interfaces are public. The main components are:</p>
Daniel Veillard4540be42000-08-19 16:40:28 +0000[diff] [blame]1709<ul>
1710 <li>an Input/Output layer</li>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]1711 <li>FTP and HTTP client layers (optional)</li>
Daniel Veillard4540be42000-08-19 16:40:28 +0000[diff] [blame]1712 <li>an Internationalization layer managing the encodings support</li>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]1713 <li>a URI module</li>
Daniel Veillard4540be42000-08-19 16:40:28 +0000[diff] [blame]1714 <li>the XML parser and its basic SAX interface</li>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]1715 <li>an HTML parser using the same SAX interface (optional)</li>
Daniel Veillard4540be42000-08-19 16:40:28 +0000[diff] [blame]1716 <li>a SAX tree module to build an in-memory DOM representation</li>
1717 <li>a tree module to manipulate the DOM representation</li>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]1718 <li>a validation module using the DOM representation (optional)</li>
Daniel Veillard4540be42000-08-19 16:40:28 +0000[diff] [blame]1719 <li>an XPath module for global lookup in a DOM representation
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]1720 (optional)</li>
1721 <li>a debug module (optional)</li>
Daniel Veillard4540be42000-08-19 16:40:28 +0000[diff] [blame]1722</ul>
1723
1724<p>Graphically this gives the following:</p>
1725
1726<p><img src="libxml.gif" alt="a graphical view of the various"></p>
1727
1728<p></p>
1729
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]1730<h2><a name="tree">The tree output</a></h2>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1731
1732<p>The parser returns a tree built during the document analysis. The value
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]1733returned is an <strong>xmlDocPtr</strong> (i.e., a pointer to an
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1734<strong>xmlDoc</strong> structure). This structure contains information such
Daniel Veillard306be992000-07-03 12:38:45 +0000[diff] [blame]1735as the file name, the document type, and a <strong>children</strong> pointer
1736which is the root of the document (or more exactly the first child under the
1737root which is the document). The tree is made of <strong>xmlNode</strong>s,
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]1738chained in double-linked lists of siblings and with a children&lt;-&gt;parent
Daniel Veillard306be992000-07-03 12:38:45 +0000[diff] [blame]1739relationship. An xmlNode can also carry properties (a chain of xmlAttr
1740structures). An attribute may have a value which is a list of TEXT or
1741ENTITY_REF nodes.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1742
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1743<p>Here is an example (erroneous with respect to the XML spec since there
1744should be only one ELEMENT under the root):</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1745
1746<p><img src="structure.gif" alt=" structure.gif "></p>
1747
1748<p>In the source package there is a small program (not installed by default)
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]1749called <strong>xmllint</strong> which parses XML files given as argument and
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1750prints them back as parsed. This is useful for detecting errors both in XML
1751code and in the XML parser itself. It has an option <strong>--debug</strong>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]1752which prints the actual in-memory structure of the document; here is the
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1753result with the <a href="#example">example</a> given before:</p>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]1754<pre>DOCUMENT
1755version=1.0
1756standalone=true
1757 ELEMENT EXAMPLE
1758 ATTRIBUTE prop1
1759 TEXT
1760 content=gnome is great
1761 ATTRIBUTE prop2
1762 ENTITY_REF
1763 TEXT
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]1764 content= linux too
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]1765 ELEMENT head
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]1766 ELEMENT title
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]1767 TEXT
1768 content=Welcome to Gnome
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]1769 ELEMENT chapter
1770 ELEMENT title
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]1771 TEXT
1772 content=The Linux adventure
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]1773 ELEMENT p
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]1774 TEXT
1775 content=bla bla bla ...
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]1776 ELEMENT image
1777 ATTRIBUTE href
1778 TEXT
1779 content=linus.gif
1780 ELEMENT p
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]1781 TEXT
1782 content=...</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1783
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1784<p>This should be useful for learning the internal representation model.</p>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]1785
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]1786<h2><a name="interface">The SAX interface</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1787
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]1788<p>Sometimes the DOM tree output is just too large to fit reasonably into
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1789memory. 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]1790loaded using libxml), it's better to use the SAX interface of libxml. SAX is
1791a <strong>callback-based interface</strong> to the parser. Before parsing,
1792the application layer registers a customized set of callbacks which are
1793called by the library as it progresses through the XML input.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1794
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1795<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]1796libxml, see the <a
1797href="http://www.daa.com.au/~james/gnome/xml-sax/xml-sax.html">nice
1798documentation</a>.written by <a href="mailto:james@daa.com.au">James
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1799Henstridge</a>.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1800
1801<p>You can debug the SAX behaviour by using the <strong>testSAX</strong>
1802program located in the gnome-xml module (it's usually not shipped in the
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1803binary packages of libxml, but you can find it in the tar source
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]1804distribution). Here is the sequence of callbacks that would be reported by
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1805testSAX when parsing the example XML document shown earlier:</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1806<pre>SAX.setDocumentLocator()
1807SAX.startDocument()
1808SAX.getEntity(amp)
1809SAX.startElement(EXAMPLE, prop1='gnome is great', prop2='&amp;amp; linux too')
1810SAX.characters( , 3)
1811SAX.startElement(head)
1812SAX.characters( , 4)
1813SAX.startElement(title)
1814SAX.characters(Welcome to Gnome, 16)
1815SAX.endElement(title)
1816SAX.characters( , 3)
1817SAX.endElement(head)
1818SAX.characters( , 3)
1819SAX.startElement(chapter)
1820SAX.characters( , 4)
1821SAX.startElement(title)
1822SAX.characters(The Linux adventure, 19)
1823SAX.endElement(title)
1824SAX.characters( , 4)
1825SAX.startElement(p)
1826SAX.characters(bla bla bla ..., 15)
1827SAX.endElement(p)
1828SAX.characters( , 4)
1829SAX.startElement(image, href='linus.gif')
1830SAX.endElement(image)
1831SAX.characters( , 4)
1832SAX.startElement(p)
1833SAX.characters(..., 3)
1834SAX.endElement(p)
1835SAX.characters( , 3)
1836SAX.endElement(chapter)
1837SAX.characters( , 1)
1838SAX.endElement(EXAMPLE)
1839SAX.endDocument()</pre>
1840
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]1841<p>Most of the other interfaces of libxml are based on the DOM tree-building
1842facility, so nearly everything up to the end of this document presupposes the
1843use of the standard DOM tree build. Note that the DOM tree itself is built by
1844a set of registered default callbacks, without internal specific
1845interface.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1846
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]1847<h2><a name="Validation">Validation &amp; DTDs</a></h2>
1848
1849<p>Table of Content:</p>
1850<ol>
1851 <li><a href="#General5">General overview</a></li>
1852 <li><a href="#definition">The definition</a></li>
1853 <li><a href="#Simple">Simple rules</a>
1854 <ol>
Daniel Veillard9c466822001-10-25 12:03:39 +0000[diff] [blame]1855 <li><a href="#reference">How to reference a DTD from a document</a></li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]1856 <li><a href="#Declaring">Declaring elements</a></li>
1857 <li><a href="#Declaring1">Declaring attributes</a></li>
1858 </ol>
1859 </li>
1860 <li><a href="#Some">Some examples</a></li>
1861 <li><a href="#validate">How to validate</a></li>
1862 <li><a href="#Other">Other resources</a></li>
1863</ol>
1864
1865<h3><a name="General5">General overview</a></h3>
1866
1867<p>Well what is validation and what is a DTD ?</p>
1868
1869<p>DTD is the acronym for Document Type Definition. This is a description of
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1870the 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^]1871specification, and allows to describe and check that a given document
1872instance conforms to a set of rules detailing its structure and content.</p>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]1873
1874<p>Validation is the process of checking a document against a DTD (more
1875generally against a set of construction rules).</p>
1876
1877<p>The validation process and building DTDs are the two most difficult parts
1878of the XML life cycle. Briefly a DTD defines all the possibles element to be
1879found within your document, what is the formal shape of your document tree
1880(by defining the allowed content of an element, either text, a regular
1881expression for the allowed list of children, or mixed content i.e. both text
1882and children). The DTD also defines the allowed attributes for all elements
1883and the types of the attributes.</p>
1884
1885<h3><a name="definition1">The definition</a></h3>
1886
1887<p>The <a href="http://www.w3.org/TR/REC-xml">W3C XML Recommendation</a> (<a
1888href="http://www.xml.com/axml/axml.html">Tim Bray's annotated version of
1889Rev1</a>):</p>
1890<ul>
1891 <li><a href="http://www.w3.org/TR/REC-xml#elemdecls">Declaring
1892 elements</a></li>
1893 <li><a href="http://www.w3.org/TR/REC-xml#attdecls">Declaring
1894 attributes</a></li>
1895</ul>
1896
1897<p>(unfortunately) all this is inherited from the SGML world, the syntax is
1898ancient...</p>
1899
1900<h3><a name="Simple1">Simple rules</a></h3>
1901
1902<p>Writing DTD can be done in multiple ways, the rules to build them if you
1903need something fixed or something which can evolve over time can be radically
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1904different. Really complex DTD like DocBook ones are flexible but quite harder
1905to design. I will just focus on DTDs for a formats with a fixed simple
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]1906structure. It is just a set of basic rules, and definitely not exhaustive nor
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1907usable for complex DTD design.</p>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]1908
1909<h4><a name="reference1">How to reference a DTD from a document</a>:</h4>
1910
1911<p>Assuming the top element of the document is <code>spec</code> and the dtd
1912is placed in the file <code>mydtd</code> in the subdirectory
1913<code>dtds</code> of the directory from where the document were loaded:</p>
1914
1915<p><code>&lt;!DOCTYPE spec SYSTEM "dtds/mydtd"&gt;</code></p>
1916
1917<p>Notes:</p>
1918<ul>
1919 <li>the system string is actually an URI-Reference (as defined in <a
1920 href="http://www.ietf.org/rfc/rfc2396.txt">RFC 2396</a>) so you can use a
1921 full URL string indicating the location of your DTD on the Web, this is a
1922 really good thing to do if you want others to validate your document</li>
1923 <li>it is also possible to associate a <code>PUBLIC</code> identifier (a
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1924 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]1925 without having to locate it on the web</li>
1926 <li>a dtd contains a set of elements and attributes declarations, but they
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1927 don't define what the root of the document should be. This is explicitly
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]1928 told to the parser/validator as the first element of the
1929 <code>DOCTYPE</code> declaration.</li>
1930</ul>
1931
1932<h4><a name="Declaring2">Declaring elements</a>:</h4>
1933
1934<p>The following declares an element <code>spec</code>:</p>
1935
1936<p><code>&lt;!ELEMENT spec (front, body, back?)&gt;</code></p>
1937
1938<p>it also expresses that the spec element contains one <code>front</code>,
Daniel Veillardc0801af2002-05-28 16:28:42 +0000[diff] [blame^]1939one <code>body</code> and one optional <code>back</code> children elements in
1940this order. The declaration of one element of the structure and its content
1941are done in a single declaration. Similarly the following declares
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]1942<code>div1</code> elements:</p>
1943
Daniel Veillard51737272002-01-23 23:10:38 +0000[diff] [blame]1944<p><code>&lt;!ELEMENT div1 (head, (p | list | note)*, div2?)&gt;</code></p>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]1945
1946<p>means div1 contains one <code>head</code> then a series of optional
1947<code>p</code>, <code>list</code>s and <code>note</code>s and then an
1948optional <code>div2</code>. And last but not least an element can contain
1949text:</p>
1950
1951<p><code>&lt;!ELEMENT b (#PCDATA)&gt;</code></p>
1952
1953<p><code>b</code> contains text or being of mixed content (text and elements
1954in no particular order):</p>
1955
1956<p><code>&lt;!ELEMENT p (#PCDATA|a|ul|b|i|em)*&gt;</code></p>
1957
1958<p><code>p </code>can contain text or <code>a</code>, <code>ul</code>,
1959<code>b</code>, <code>i </code>or <code>em</code> elements in no particular
1960order.</p>
1961
1962<h4><a name="Declaring1">Declaring attributes</a>:</h4>
1963
1964<p>again the attributes declaration includes their content definition:</p>
1965
1966<p><code>&lt;!ATTLIST termdef name CDATA #IMPLIED&gt;</code></p>
1967
1968<p>means that the element <code>termdef</code> can have a <code>name</code>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1969attribute containing text (<code>CDATA</code>) and which is optional
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]1970(<code>#IMPLIED</code>). The attribute value can also be defined within a
1971set:</p>
1972
1973<p><code>&lt;!ATTLIST list type (bullets|ordered|glossary)
1974"ordered"&gt;</code></p>
1975
1976<p>means <code>list</code> element have a <code>type</code> attribute with 3
1977allowed values "bullets", "ordered" or "glossary" and which default to
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1978"ordered" if the attribute is not explicitly specified.</p>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]1979
1980<p>The content type of an attribute can be text (<code>CDATA</code>),
1981anchor/reference/references
1982(<code>ID</code>/<code>IDREF</code>/<code>IDREFS</code>), entity(ies)
1983(<code>ENTITY</code>/<code>ENTITIES</code>) or name(s)
1984(<code>NMTOKEN</code>/<code>NMTOKENS</code>). The following defines that a
1985<code>chapter</code> element can have an optional <code>id</code> attribute
1986of type <code>ID</code>, usable for reference from attribute of type
1987IDREF:</p>
1988
1989<p><code>&lt;!ATTLIST chapter id ID #IMPLIED&gt;</code></p>
1990
1991<p>The last value of an attribute definition can be <code>#REQUIRED
1992</code>meaning that the attribute has to be given, <code>#IMPLIED</code>
1993meaning that it is optional, or the default value (possibly prefixed by
1994<code>#FIXED</code> if it is the only allowed).</p>
1995
1996<p>Notes:</p>
1997<ul>
1998 <li>usually the attributes pertaining to a given element are declared in a
1999 single expression, but it is just a convention adopted by a lot of DTD
2000 writers:
2001 <pre>&lt;!ATTLIST termdef
2002 id ID #REQUIRED
2003 name CDATA #IMPLIED&gt;</pre>
2004 <p>The previous construct defines both <code>id</code> and
2005 <code>name</code> attributes for the element <code>termdef</code></p>
2006 </li>
2007</ul>
2008
2009<h3><a name="Some1">Some examples</a></h3>
2010
2011<p>The directory <code>test/valid/dtds/</code> in the libxml distribution
2012contains some complex DTD examples. The <code>test/valid/dia.xml</code>
2013example shows an XML file where the simple DTD is directly included within
2014the document.</p>
2015
2016<h3><a name="validate1">How to validate</a></h3>
2017
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]2018<p>The simplest is to use the xmllint program coming with libxml. The
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2019<code>--valid</code> option turn on validation of the files given as input,
2020for example the following validates a copy of the first revision of the XML
20211.0 specification:</p>
2022
2023<p><code>xmllint --valid --noout test/valid/REC-xml-19980210.xml</code></p>
2024
2025<p>the -- noout is used to not output the resulting tree.</p>
2026
2027<p>The <code>--dtdvalid dtd</code> allows to validate the document(s) against
2028a given DTD.</p>
2029
2030<p>Libxml exports an API to handle DTDs and validation, check the <a
2031href="http://xmlsoft.org/html/libxml-valid.html">associated
2032description</a>.</p>
2033
2034<h3><a name="Other1">Other resources</a></h3>
2035
2036<p>DTDs are as old as SGML. So there may be a number of examples on-line, I
2037will just list one for now, others pointers welcome:</p>
2038<ul>
2039 <li><a href="http://www.xml101.com:8081/dtd/">XML-101 DTD</a></li>
2040</ul>
2041
2042<p>I suggest looking at the examples found under test/valid/dtd and any of
2043the large number of books available on XML. The dia example in test/valid
2044should be both simple and complete enough to allow you to build your own.</p>
2045
2046<p></p>
2047
2048<h2><a name="Memory">Memory Management</a></h2>
2049
2050<p>Table of Content:</p>
2051<ol>
2052 <li><a href="#General3">General overview</a></li>
Daniel Veillard9c466822001-10-25 12:03:39 +0000[diff] [blame]2053 <li><a href="#setting">Setting libxml set of memory routines</a></li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2054 <li><a href="#cleanup">Cleaning up after parsing</a></li>
2055 <li><a href="#Debugging">Debugging routines</a></li>
2056 <li><a href="#General4">General memory requirements</a></li>
2057</ol>
2058
2059<h3><a name="General3">General overview</a></h3>
2060
2061<p>The module <code><a
2062href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlmemory.h</a></code>
2063provides the interfaces to the libxml memory system:</p>
2064<ul>
2065 <li>libxml does not use the libc memory allocator directly but xmlFree(),
2066 xmlMalloc() and xmlRealloc()</li>
2067 <li>those routines can be reallocated to a specific set of routine, by
2068 default the libc ones i.e. free(), malloc() and realloc()</li>
2069 <li>the xmlmemory.c module includes a set of debugging routine</li>
2070</ul>
2071
2072<h3><a name="setting">Setting libxml set of memory routines</a></h3>
2073
2074<p>It is sometimes useful to not use the default memory allocator, either for
2075debugging, analysis or to implement a specific behaviour on memory management
2076(like on embedded systems). Two function calls are available to do so:</p>
2077<ul>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]2078 <li><a href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlMemGet
2079 ()</a> which return the current set of functions in use by the parser</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2080 <li><a
2081 href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlMemSetup()</a>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]2082 which allow to set up a new set of memory allocation functions</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2083</ul>
2084
2085<p>Of course a call to xmlMemSetup() should probably be done before calling
2086any other libxml routines (unless you are sure your allocations routines are
2087compatibles).</p>
2088
2089<h3><a name="cleanup">Cleaning up after parsing</a></h3>
2090
2091<p>Libxml is not stateless, there is a few set of memory structures needing
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]2092allocation before the parser is fully functional (some encoding structures
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2093for example). This also mean that once parsing is finished there is a tiny
2094amount of memory (a few hundred bytes) which can be recollected if you don't
2095reuse the parser immediately:</p>
2096<ul>
2097 <li><a href="http://xmlsoft.org/html/libxml-parser.html">xmlCleanupParser
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]2098 ()</a> is a centralized routine to free the parsing states. Note that it
2099 won't deallocate any produced tree if any (use the xmlFreeDoc() and
2100 related routines for this).</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2101 <li><a href="http://xmlsoft.org/html/libxml-parser.html">xmlInitParser
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]2102 ()</a> is the dual routine allowing to preallocate the parsing state
2103 which can be useful for example to avoid initialization reentrancy
2104 problems when using libxml in multithreaded applications</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2105</ul>
2106
2107<p>Generally xmlCleanupParser() is safe, if needed the state will be rebuild
2108at the next invocation of parser routines, but be careful of the consequences
2109in multithreaded applications.</p>
2110
2111<h3><a name="Debugging">Debugging routines</a></h3>
2112
2113<p>When configured using --with-mem-debug flag (off by default), libxml uses
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]2114a set of memory allocation debugging routines keeping track of all allocated
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2115blocks and the location in the code where the routine was called. A couple of
2116other debugging routines allow to dump the memory allocated infos to a file
2117or call a specific routine when a given block number is allocated:</p>
2118<ul>
2119 <li><a
2120 href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlMallocLoc()</a>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]2121 <a
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2122 href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlReallocLoc()</a>
2123 and <a
2124 href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlMemStrdupLoc()</a>
2125 are the memory debugging replacement allocation routines</li>
2126 <li><a href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlMemoryDump
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]2127 ()</a> dumps all the informations about the allocated memory block lefts
2128 in the <code>.memdump</code> file</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2129</ul>
2130
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]2131<p>When developing libxml memory debug is enabled, the tests programs call
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2132xmlMemoryDump () and the "make test" regression tests will check for any
2133memory leak during the full regression test sequence, this helps a lot
2134ensuring that libxml does not leak memory and bullet proof memory
2135allocations use (some libc implementations are known to be far too permissive
2136resulting in major portability problems!).</p>
2137
2138<p>If the .memdump reports a leak, it displays the allocation function and
2139also tries to give some informations about the content and structure of the
2140allocated blocks left. This is sufficient in most cases to find the culprit,
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]2141but not always. Assuming the allocation problem is reproducible, it is
2142possible to find more easily:</p>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2143<ol>
2144 <li>write down the block number xxxx not allocated</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]2145 <li>export the environment variable XML_MEM_BREAKPOINT=xxxx , the easiest
Daniel Veillard75794822002-04-11 16:24:32 +0000[diff] [blame]2146 when using GDB is to simply give the command
2147 <p><code>set environment XML_MEM_BREAKPOINT xxxx</code></p>
2148 <p>before running the program.</p>
2149 </li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2150 <li>run the program under a debugger and set a breakpoint on
2151 xmlMallocBreakpoint() a specific function called when this precise block
2152 is allocated</li>
2153 <li>when the breakpoint is reached you can then do a fine analysis of the
2154 allocation an step to see the condition resulting in the missing
2155 deallocation.</li>
2156</ol>
2157
2158<p>I used to use a commercial tool to debug libxml memory problems but after
2159noticing that it was not detecting memory leaks that simple mechanism was
Daniel Veillard75794822002-04-11 16:24:32 +0000[diff] [blame]2160used and proved extremely efficient until now. Lately I have also used <a
2161href="http://developer.kde.org/~sewardj/">valgrind</a> with quite some
2162success, it is tied to the i386 architecture since it works by emulating the
2163processor and instruction set, it is slow but extremely efficient, i.e. it
2164spot memory usage errors in a very precise way.</p>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2165
2166<h3><a name="General4">General memory requirements</a></h3>
2167
2168<p>How much libxml memory require ? It's hard to tell in average it depends
2169of a number of things:</p>
2170<ul>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]2171 <li>the parser itself should work in a fixed amount of memory, except for
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2172 information maintained about the stacks of names and entities locations.
2173 The I/O and encoding handlers will probably account for a few KBytes.
2174 This is true for both the XML and HTML parser (though the HTML parser
2175 need more state).</li>
2176 <li>If you are generating the DOM tree then memory requirements will grow
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]2177 nearly linear with the size of the data. In general for a balanced
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2178 textual document the internal memory requirement is about 4 times the
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]2179 size of the UTF8 serialization of this document (example the XML-1.0
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2180 recommendation is a bit more of 150KBytes and takes 650KBytes of main
2181 memory when parsed). Validation will add a amount of memory required for
2182 maintaining the external Dtd state which should be linear with the
2183 complexity of the content model defined by the Dtd</li>
2184 <li>If you don't care about the advanced features of libxml like
2185 validation, DOM, XPath or XPointer, but really need to work fixed memory
2186 requirements, then the SAX interface should be used.</li>
2187</ul>
2188
2189<p></p>
2190
2191<h2><a name="Encodings">Encodings support</a></h2>
2192
2193<p>Table of Content:</p>
2194<ol>
2195 <li><a href="encoding.html#What">What does internationalization support
2196 mean ?</a></li>
2197 <li><a href="encoding.html#internal">The internal encoding, how and
2198 why</a></li>
2199 <li><a href="encoding.html#implemente">How is it implemented ?</a></li>
2200 <li><a href="encoding.html#Default">Default supported encodings</a></li>
2201 <li><a href="encoding.html#extend">How to extend the existing
2202 support</a></li>
2203</ol>
2204
2205<h3><a name="What">What does internationalization support mean ?</a></h3>
2206
2207<p>XML was designed from the start to allow the support of any character set
2208by using Unicode. Any conformant XML parser has to support the UTF-8 and
2209UTF-16 default encodings which can both express the full unicode ranges. UTF8
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]2210is a variable length encoding whose greatest points are to reuse the same
2211encoding for ASCII and to save space for Western encodings, but it is a bit
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2212more complex to handle in practice. UTF-16 use 2 bytes per characters (and
2213sometimes combines two pairs), it makes implementation easier, but looks a
2214bit overkill for Western languages encoding. Moreover the XML specification
2215allows document to be encoded in other encodings at the condition that they
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]2216are clearly labeled as such. For example the following is a wellformed XML
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2217document encoded in ISO-8859 1 and using accentuated letter that we French
2218likes for both markup and content:</p>
2219<pre>&lt;?xml version="1.0" encoding="ISO-8859-1"?&gt;
2220&lt;très&gt;là&lt;/très&gt;</pre>
2221
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]2222<p>Having internationalization support in libxml means the following:</p>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2223<ul>
2224 <li>the document is properly parsed</li>
2225 <li>informations about it's encoding are saved</li>
2226 <li>it can be modified</li>
2227 <li>it can be saved in its original encoding</li>
2228 <li>it can also be saved in another encoding supported by libxml (for
2229 example straight UTF8 or even an ASCII form)</li>
2230</ul>
2231
2232<p>Another very important point is that the whole libxml API, with the
2233exception of a few routines to read with a specific encoding or save to a
2234specific encoding, is completely agnostic about the original encoding of the
2235document.</p>
2236
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]2237<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]2238the same rules too, the following document will be (as of 2.2.2) handled in
2239an internationalized fashion by libxml too:</p>
2240<pre>&lt;!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"
2241 "http://www.w3.org/TR/REC-html40/loose.dtd"&gt;
2242&lt;html lang="fr"&gt;
2243&lt;head&gt;
2244 &lt;META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=ISO-8859-1"&gt;
2245&lt;/head&gt;
2246&lt;body&gt;
2247&lt;p&gt;W3C crée des standards pour le Web.&lt;/body&gt;
2248&lt;/html&gt;</pre>
2249
2250<h3><a name="internal">The internal encoding, how and why</a></h3>
2251
2252<p>One of the core decision was to force all documents to be converted to a
2253default internal encoding, and that encoding to be UTF-8, here are the
2254rationale for those choices:</p>
2255<ul>
2256 <li>keeping the native encoding in the internal form would force the libxml
2257 users (or the code associated) to be fully aware of the encoding of the
2258 original document, for examples when adding a text node to a document,
2259 the content would have to be provided in the document encoding, i.e. the
2260 client code would have to check it before hand, make sure it's conformant
2261 to the encoding, etc ... Very hard in practice, though in some specific
2262 cases this may make sense.</li>
2263 <li>the second decision was which encoding. From the XML spec only UTF8 and
2264 UTF16 really makes sense as being the two only encodings for which there
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]2265 is mandatory support. UCS-4 (32 bits fixed size encoding) could be
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2266 considered an intelligent choice too since it's a direct Unicode mapping
2267 support. I selected UTF-8 on the basis of efficiency and compatibility
2268 with surrounding software:
2269 <ul>
2270 <li>UTF-8 while a bit more complex to convert from/to (i.e. slightly
2271 more costly to import and export CPU wise) is also far more compact
2272 than UTF-16 (and UCS-4) for a majority of the documents I see it used
2273 for right now (RPM RDF catalogs, advogato data, various configuration
2274 file formats, etc.) and the key point for today's computer
2275 architecture is efficient uses of caches. If one nearly double the
2276 memory requirement to store the same amount of data, this will trash
2277 caches (main memory/external caches/internal caches) and my take is
2278 that this harms the system far more than the CPU requirements needed
2279 for the conversion to UTF-8</li>
2280 <li>Most of libxml version 1 users were using it with straight ASCII
2281 most of the time, doing the conversion with an internal encoding
2282 requiring all their code to be rewritten was a serious show-stopper
2283 for using UTF-16 or UCS-4.</li>
2284 <li>UTF-8 is being used as the de-facto internal encoding standard for
2285 related code like the <a href="http://www.pango.org/">pango</a>
2286 upcoming Gnome text widget, and a lot of Unix code (yep another place
2287 where Unix programmer base takes a different approach from Microsoft
2288 - they are using UTF-16)</li>
2289 </ul>
2290 </li>
2291</ul>
2292
2293<p>What does this mean in practice for the libxml user:</p>
2294<ul>
2295 <li>xmlChar, the libxml data type is a byte, those bytes must be assembled
2296 as UTF-8 valid strings. The proper way to terminate an xmlChar * string
2297 is simply to append 0 byte, as usual.</li>
2298 <li>One just need to make sure that when using chars outside the ASCII set,
2299 the values has been properly converted to UTF-8</li>
2300</ul>
2301
2302<h3><a name="implemente">How is it implemented ?</a></h3>
2303
2304<p>Let's describe how all this works within libxml, basically the I18N
2305(internationalization) support get triggered only during I/O operation, i.e.
2306when reading a document or saving one. Let's look first at the reading
2307sequence:</p>
2308<ol>
2309 <li>when a document is processed, we usually don't know the encoding, a
2310 simple heuristic allows to detect UTF-18 and UCS-4 from whose where the
2311 ASCII range (0-0x7F) maps with ASCII</li>
2312 <li>the xml declaration if available is parsed, including the encoding
2313 declaration. At that point, if the autodetected encoding is different
2314 from the one declared a call to xmlSwitchEncoding() is issued.</li>
2315 <li>If there is no encoding declaration, then the input has to be in either
2316 UTF-8 or UTF-16, if it is not then at some point when processing the
2317 input, the converter/checker of UTF-8 form will raise an encoding error.
2318 You may end-up with a garbled document, or no document at all ! Example:
2319 <pre>~/XML -&gt; ./xmllint err.xml
2320err.xml:1: error: Input is not proper UTF-8, indicate encoding !
2321&lt;très&gt;là&lt;/très&gt;
2322 ^
2323err.xml:1: error: Bytes: 0xE8 0x73 0x3E 0x6C
2324&lt;très&gt;là&lt;/très&gt;
2325 ^</pre>
2326 </li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]2327 <li>xmlSwitchEncoding() does an encoding name lookup, canonicalize it, and
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2328 then search the default registered encoding converters for that encoding.
2329 If it's not within the default set and iconv() support has been compiled
2330 it, it will ask iconv for such an encoder. If this fails then the parser
2331 will report an error and stops processing:
2332 <pre>~/XML -&gt; ./xmllint err2.xml
2333err2.xml:1: error: Unsupported encoding UnsupportedEnc
2334&lt;?xml version="1.0" encoding="UnsupportedEnc"?&gt;
2335 ^</pre>
2336 </li>
Daniel Veillard46c5c1d2002-05-20 07:15:54 +0000[diff] [blame]2337 <li>From that point the encoder processes progressively the input (it is
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2338 plugged as a front-end to the I/O module) for that entity. It captures
2339 and convert on-the-fly the document to be parsed to UTF-8. The parser
2340 itself just does UTF-8 checking of this input and process it
2341 transparently. The only difference is that the encoding information has
2342 been added to the parsing context (more precisely to the input
2343 corresponding to this entity).</li>
2344 <li>The result (when using DOM) is an internal form completely in UTF-8
2345 with just an encoding information on the document node.</li>
2346</ol>
2347
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]2348<p>Ok then what happens when saving the document (assuming you
2349collected/built an xmlDoc DOM like structure) ? It depends on the function
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2350called, xmlSaveFile() will just try to save in the original encoding, while
2351xmlSaveFileTo() and xmlSaveFileEnc() can optionally save to a given
2352encoding:</p>
2353<ol>
2354 <li>if no encoding is given, libxml will look for an encoding value
2355 associated to the document and if it exists will try to save to that
2356 encoding,
2357 <p>otherwise everything is written in the internal form, i.e. UTF-8</p>
2358 </li>
2359 <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]2360 document, libxml will again canonicalize the encoding name, lookup for a
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2361 converter in the registered set or through iconv. If not found the
2362 function will return an error code</li>
2363 <li>the converter is placed before the I/O buffer layer, as another kind of
2364 buffer, then libxml will simply push the UTF-8 serialization to through
2365 that buffer, which will then progressively be converted and pushed onto
2366 the I/O layer.</li>
2367 <li>It is possible that the converter code fails on some input, for example
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]2368 trying to push an UTF-8 encoded Chinese character through the UTF-8 to
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2369 ISO-8859-1 converter won't work. Since the encoders are progressive they
2370 will just report the error and the number of bytes converted, at that
2371 point libxml will decode the offending character, remove it from the
2372 buffer and replace it with the associated charRef encoding &amp;#123; and
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]2373 resume the conversion. This guarantees that any document will be saved
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2374 without losses (except for markup names where this is not legal, this is
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]2375 a problem in the current version, in practice avoid using non-ascii
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2376 characters for tags or attributes names @@). A special "ascii" encoding
2377 name is used to save documents to a pure ascii form can be used when
2378 portability is really crucial</li>
2379</ol>
2380
2381<p>Here is a few examples based on the same test document:</p>
2382<pre>~/XML -&gt; ./xmllint isolat1
2383&lt;?xml version="1.0" encoding="ISO-8859-1"?&gt;
2384&lt;très&gt;là&lt;/très&gt;
2385~/XML -&gt; ./xmllint --encode UTF-8 isolat1
2386&lt;?xml version="1.0" encoding="UTF-8"?&gt;
2387&lt;très&gt;là  &lt;/très&gt;
2388~/XML -&gt; </pre>
2389
2390<p>The same processing is applied (and reuse most of the code) for HTML I18N
2391processing. Looking up and modifying the content encoding is a bit more
2392difficult since it is located in a &lt;meta&gt; tag under the &lt;head&gt;,
2393so a couple of functions htmlGetMetaEncoding() and htmlSetMetaEncoding() have
2394been provided. The parser also attempts to switch encoding on the fly when
2395detecting such a tag on input. Except for that the processing is the same
2396(and again reuses the same code).</p>
2397
2398<h3><a name="Default">Default supported encodings</a></h3>
2399
2400<p>libxml has a set of default converters for the following encodings
2401(located in encoding.c):</p>
2402<ol>
2403 <li>UTF-8 is supported by default (null handlers)</li>
2404 <li>UTF-16, both little and big endian</li>
2405 <li>ISO-Latin-1 (ISO-8859-1) covering most western languages</li>
2406 <li>ASCII, useful mostly for saving</li>
2407 <li>HTML, a specific handler for the conversion of UTF-8 to ASCII with HTML
2408 predefined entities like &amp;copy; for the Copyright sign.</li>
2409</ol>
2410
Daniel Veillardc0801af2002-05-28 16:28:42 +0000[diff] [blame^]2411<p>More over when compiled on an Unix platform with iconv support the full
2412set of encodings supported by iconv can be instantly be used by libxml. On a
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2413linux machine with glibc-2.1 the list of supported encodings and aliases fill
24143 full pages, and include UCS-4, the full set of ISO-Latin encodings, and the
2415various Japanese ones.</p>
2416
2417<h4>Encoding aliases</h4>
2418
2419<p>From 2.2.3, libxml has support to register encoding names aliases. The
2420goal is to be able to parse document whose encoding is supported but where
2421the name differs (for example from the default set of names accepted by
2422iconv). The following functions allow to register and handle new aliases for
2423existing encodings. Once registered libxml will automatically lookup the
2424aliases when handling a document:</p>
2425<ul>
2426 <li>int xmlAddEncodingAlias(const char *name, const char *alias);</li>
2427 <li>int xmlDelEncodingAlias(const char *alias);</li>
2428 <li>const char * xmlGetEncodingAlias(const char *alias);</li>
2429 <li>void xmlCleanupEncodingAliases(void);</li>
2430</ul>
2431
2432<h3><a name="extend">How to extend the existing support</a></h3>
2433
2434<p>Well adding support for new encoding, or overriding one of the encoders
2435(assuming it is buggy) should not be hard, just write an input and output
2436conversion routines to/from UTF-8, and register them using
2437xmlNewCharEncodingHandler(name, xxxToUTF8, UTF8Toxxx), and they will be
2438called automatically if the parser(s) encounter such an encoding name
2439(register it uppercase, this will help). The description of the encoders,
2440their arguments and expected return values are described in the encoding.h
2441header.</p>
2442
2443<p>A quick note on the topic of subverting the parser to use a different
2444internal encoding than UTF-8, in some case people will absolutely want to
2445keep the internal encoding different, I think it's still possible (but the
2446encoding must be compliant with ASCII on the same subrange) though I didn't
2447tried it. The key is to override the default conversion routines (by
2448registering null encoders/decoders for your charsets), and bypass the UTF-8
2449checking of the parser by setting the parser context charset
2450(ctxt-&gt;charset) to something different than XML_CHAR_ENCODING_UTF8, but
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]2451there is no guarantee that this will work. You may also have some troubles
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2452saving back.</p>
2453
2454<p>Basically proper I18N support is important, this requires at least
2455libxml-2.0.0, but a lot of features and corrections are really available only
2456starting 2.2.</p>
2457
2458<h2><a name="IO">I/O Interfaces</a></h2>
2459
2460<p>Table of Content:</p>
2461<ol>
2462 <li><a href="#General1">General overview</a></li>
2463 <li><a href="#basic">The basic buffer type</a></li>
2464 <li><a href="#Input">Input I/O handlers</a></li>
2465 <li><a href="#Output">Output I/O handlers</a></li>
2466 <li><a href="#entities">The entities loader</a></li>
2467 <li><a href="#Example2">Example of customized I/O</a></li>
2468</ol>
2469
2470<h3><a name="General1">General overview</a></h3>
2471
2472<p>The module <code><a
2473href="http://xmlsoft.org/html/libxml-xmlio.html">xmlIO.h</a></code> provides
2474the interfaces to the libxml I/O system. This consists of 4 main parts:</p>
2475<ul>
2476 <li>Entities loader, this is a routine which tries to fetch the entities
2477 (files) based on their PUBLIC and SYSTEM identifiers. The default loader
2478 don't look at the public identifier since libxml do not maintain a
2479 catalog. You can redefine you own entity loader by using
2480 <code>xmlGetExternalEntityLoader()</code> and
Daniel Veillard9c466822001-10-25 12:03:39 +0000[diff] [blame]2481 <code>xmlSetExternalEntityLoader()</code>. <a href="#entities">Check the
2482 example</a>.</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2483 <li>Input I/O buffers which are a commodity structure used by the parser(s)
2484 input layer to handle fetching the informations to feed the parser. This
2485 provides buffering and is also a placeholder where the encoding
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]2486 converters to UTF8 are piggy-backed.</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2487 <li>Output I/O buffers are similar to the Input ones and fulfill similar
2488 task but when generating a serialization from a tree.</li>
2489 <li>A mechanism to register sets of I/O callbacks and associate them with
2490 specific naming schemes like the protocol part of the URIs.
2491 <p>This affect the default I/O operations and allows to use specific I/O
2492 handlers for certain names.</p>
2493 </li>
2494</ul>
2495
2496<p>The general mechanism used when loading http://rpmfind.net/xml.html for
2497example in the HTML parser is the following:</p>
2498<ol>
2499 <li>The default entity loader calls <code>xmlNewInputFromFile()</code> with
2500 the parsing context and the URI string.</li>
2501 <li>the URI string is checked against the existing registered handlers
2502 using their match() callback function, if the HTTP module was compiled
2503 in, it is registered and its match() function will succeeds</li>
2504 <li>the open() function of the handler is called and if successful will
2505 return an I/O Input buffer</li>
2506 <li>the parser will the start reading from this buffer and progressively
2507 fetch information from the resource, calling the read() function of the
2508 handler until the resource is exhausted</li>
2509 <li>if an encoding change is detected it will be installed on the input
2510 buffer, providing buffering and efficient use of the conversion
2511 routines</li>
2512 <li>once the parser has finished, the close() function of the handler is
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]2513 called once and the Input buffer and associated resources are
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2514 deallocated.</li>
2515</ol>
2516
2517<p>The user defined callbacks are checked first to allow overriding of the
2518default libxml I/O routines.</p>
2519
2520<h3><a name="basic">The basic buffer type</a></h3>
2521
2522<p>All the buffer manipulation handling is done using the
2523<code>xmlBuffer</code> type define in <code><a
2524href="http://xmlsoft.org/html/libxml-tree.html">tree.h</a> </code>which is a
2525resizable memory buffer. The buffer allocation strategy can be selected to be
2526either best-fit or use an exponential doubling one (CPU vs. memory use
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]2527trade-off). The values are <code>XML_BUFFER_ALLOC_EXACT</code> and
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2528<code>XML_BUFFER_ALLOC_DOUBLEIT</code>, and can be set individually or on a
2529system wide basis using <code>xmlBufferSetAllocationScheme()</code>. A number
2530of functions allows to manipulate buffers with names starting with the
2531<code>xmlBuffer...</code> prefix.</p>
2532
2533<h3><a name="Input">Input I/O handlers</a></h3>
2534
2535<p>An Input I/O handler is a simple structure
2536<code>xmlParserInputBuffer</code> containing a context associated to the
2537resource (file descriptor, or pointer to a protocol handler), the read() and
2538close() callbacks to use and an xmlBuffer. And extra xmlBuffer and a charset
2539encoding handler are also present to support charset conversion when
2540needed.</p>
2541
2542<h3><a name="Output">Output I/O handlers</a></h3>
2543
2544<p>An Output handler <code>xmlOutputBuffer</code> is completely similar to an
2545Input one except the callbacks are write() and close().</p>
2546
2547<h3><a name="entities">The entities loader</a></h3>
2548
2549<p>The entity loader resolves requests for new entities and create inputs for
2550the parser. Creating an input from a filename or an URI string is done
2551through the xmlNewInputFromFile() routine. The default entity loader do not
2552handle the PUBLIC identifier associated with an entity (if any). So it just
2553calls xmlNewInputFromFile() with the SYSTEM identifier (which is mandatory in
2554XML).</p>
2555
2556<p>If you want to hook up a catalog mechanism then you simply need to
2557override the default entity loader, here is an example:</p>
2558<pre>#include &lt;libxml/xmlIO.h&gt;
2559
2560xmlExternalEntityLoader defaultLoader = NULL;
2561
2562xmlParserInputPtr
2563xmlMyExternalEntityLoader(const char *URL, const char *ID,
2564 xmlParserCtxtPtr ctxt) {
2565 xmlParserInputPtr ret;
2566 const char *fileID = NULL;
2567 /* lookup for the fileID depending on ID */
2568
2569 ret = xmlNewInputFromFile(ctxt, fileID);
2570 if (ret != NULL)
2571 return(ret);
2572 if (defaultLoader != NULL)
2573 ret = defaultLoader(URL, ID, ctxt);
2574 return(ret);
2575}
2576
2577int main(..) {
2578 ...
2579
2580 /*
2581 * Install our own entity loader
2582 */
2583 defaultLoader = xmlGetExternalEntityLoader();
2584 xmlSetExternalEntityLoader(xmlMyExternalEntityLoader);
2585
2586 ...
2587}</pre>
2588
2589<h3><a name="Example2">Example of customized I/O</a></h3>
2590
2591<p>This example come from <a href="http://xmlsoft.org/messages/0708.html">a
2592real use case</a>, xmlDocDump() closes the FILE * passed by the application
2593and this was a problem. The <a
2594href="http://xmlsoft.org/messages/0711.html">solution</a> was to redefine a
2595new output handler with the closing call deactivated:</p>
2596<ol>
Daniel Veillardc0801af2002-05-28 16:28:42 +0000[diff] [blame^]2597 <li>First define a new I/O output allocator where the output don't close
2598 the file:
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2599 <pre>xmlOutputBufferPtr
2600xmlOutputBufferCreateOwn(FILE *file, xmlCharEncodingHandlerPtr encoder) {
2601    xmlOutputBufferPtr ret;
2602    
2603    if (xmlOutputCallbackInitialized == 0)
2604        xmlRegisterDefaultOutputCallbacks();
2605
2606    if (file == NULL) return(NULL);
2607    ret = xmlAllocOutputBuffer(encoder);
2608    if (ret != NULL) {
2609        ret-&gt;context = file;
2610        ret-&gt;writecallback = xmlFileWrite;
2611        ret-&gt;closecallback = NULL; /* No close callback */
2612    }
2613    return(ret); <br>
Daniel Veillard1eb24242002-03-18 11:33:03 +0000[diff] [blame]2614
Daniel Veillard34ce8be2002-03-18 19:37:11 +0000[diff] [blame]2615
2616
Daniel Veillard19274092002-03-25 16:48:03 +0000[diff] [blame]2617
Daniel Veillardb2fb8ed2002-04-01 09:33:12 +0000[diff] [blame]2618
Daniel Veillard75794822002-04-11 16:24:32 +0000[diff] [blame]2619
Daniel Veillarda7084cd2002-04-15 17:12:47 +0000[diff] [blame]2620
Daniel Veillard0bfbb422002-04-26 09:21:45 +0000[diff] [blame]2621
Daniel Veillard93d3a472002-04-26 14:04:55 +0000[diff] [blame]2622
Daniel Veillardcf27f7c2002-04-30 07:12:39 +0000[diff] [blame]2623
Daniel Veillarde6d8e202002-05-02 06:11:10 +0000[diff] [blame]2624
Daniel Veillard9b6fd302002-05-13 12:06:47 +0000[diff] [blame]2625
Daniel Veillardc0801af2002-05-28 16:28:42 +0000[diff] [blame^]2626
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2627} </pre>
2628 </li>
2629 <li>And then use it to save the document:
2630 <pre>FILE *f;
2631xmlOutputBufferPtr output;
2632xmlDocPtr doc;
2633int res;
2634
2635f = ...
2636doc = ....
2637
2638output = xmlOutputBufferCreateOwn(f, NULL);
2639res = xmlSaveFileTo(output, doc, NULL);
2640 </pre>
2641 </li>
2642</ol>
2643
2644<h2><a name="Catalog">Catalog support</a></h2>
2645
2646<p>Table of Content:</p>
2647<ol>
2648 <li><a href="General2">General overview</a></li>
2649 <li><a href="#definition">The definition</a></li>
2650 <li><a href="#Simple">Using catalogs</a></li>
2651 <li><a href="#Some">Some examples</a></li>
2652 <li><a href="#reference">How to tune catalog usage</a></li>
2653 <li><a href="#validate">How to debug catalog processing</a></li>
2654 <li><a href="#Declaring">How to create and maintain catalogs</a></li>
2655 <li><a href="#implemento">The implementor corner quick review of the
2656 API</a></li>
2657 <li><a href="#Other">Other resources</a></li>
2658</ol>
2659
2660<h3><a name="General2">General overview</a></h3>
2661
2662<p>What is a catalog? Basically it's a lookup mechanism used when an entity
2663(a file or a remote resource) references another entity. The catalog lookup
2664is inserted between the moment the reference is recognized by the software
2665(XML parser, stylesheet processing, or even images referenced for inclusion
2666in a rendering) and the time where loading that resource is actually
2667started.</p>
2668
2669<p>It is basically used for 3 things:</p>
2670<ul>
2671 <li>mapping from "logical" names, the public identifiers and a more
2672 concrete name usable for download (and URI). For example it can associate
2673 the logical name
2674 <p>"-//OASIS//DTD DocBook XML V4.1.2//EN"</p>
2675 <p>of the DocBook 4.1.2 XML DTD with the actual URL where it can be
2676 downloaded</p>
2677 <p>http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd</p>
2678 </li>
2679 <li>remapping from a given URL to another one, like an HTTP indirection
2680 saying that
2681 <p>"http://www.oasis-open.org/committes/tr.xsl"</p>
2682 <p>should really be looked at</p>
2683 <p>"http://www.oasis-open.org/committes/entity/stylesheets/base/tr.xsl"</p>
2684 </li>
2685 <li>providing a local cache mechanism allowing to load the entities
2686 associated to public identifiers or remote resources, this is a really
2687 important feature for any significant deployment of XML or SGML since it
2688 allows to avoid the aleas and delays associated to fetching remote
2689 resources.</li>
2690</ul>
2691
2692<h3><a name="definition">The definitions</a></h3>
2693
2694<p>Libxml, as of 2.4.3 implements 2 kind of catalogs:</p>
2695<ul>
2696 <li>the older SGML catalogs, the official spec is SGML Open Technical
2697 Resolution TR9401:1997, but is better understood by reading <a
2698 href="http://www.jclark.com/sp/catalog.htm">the SP Catalog page</a> from
2699 James Clark. This is relatively old and not the preferred mode of
2700 operation of libxml.</li>
2701 <li><a href="http://www.oasis-open.org/committees/entity/spec.html">XML
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]2702 Catalogs</a> is far more flexible, more recent, uses an XML syntax and
2703 should scale quite better. This is the default option of libxml.</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2704</ul>
2705
2706<p></p>
2707
2708<h3><a name="Simple">Using catalog</a></h3>
2709
2710<p>In a normal environment libxml will by default check the presence of a
2711catalog in /etc/xml/catalog, and assuming it has been correctly populated,
2712the processing is completely transparent to the document user. To take a
2713concrete example, suppose you are authoring a DocBook document, this one
2714starts with the following DOCTYPE definition:</p>
2715<pre>&lt;?xml version='1.0'?&gt;
2716&lt;!DOCTYPE book PUBLIC "-//Norman Walsh//DTD DocBk XML V3.1.4//EN"
2717 "http://nwalsh.com/docbook/xml/3.1.4/db3xml.dtd"&gt;</pre>
2718
2719<p>When validating the document with libxml, the catalog will be
2720automatically consulted to lookup the public identifier "-//Norman Walsh//DTD
2721DocBk XML V3.1.4//EN" and the system identifier
2722"http://nwalsh.com/docbook/xml/3.1.4/db3xml.dtd", and if these entities have
2723been installed on your system and the catalogs actually point to them, libxml
2724will fetch them from the local disk.</p>
2725
2726<p style="font-size: 10pt"><strong>Note</strong>: Really don't use this
2727DOCTYPE example it's a really old version, but is fine as an example.</p>
2728
2729<p>Libxml will check the catalog each time that it is requested to load an
2730entity, this includes DTD, external parsed entities, stylesheets, etc ... If
2731your system is correctly configured all the authoring phase and processing
2732should use only local files, even if your document stays portable because it
2733uses the canonical public and system ID, referencing the remote document.</p>
2734
2735<h3><a name="Some">Some examples:</a></h3>
2736
2737<p>Here is a couple of fragments from XML Catalogs used in libxml early
2738regression tests in <code>test/catalogs</code> :</p>
2739<pre>&lt;?xml version="1.0"?&gt;
2740&lt;!DOCTYPE catalog PUBLIC
2741 "-//OASIS//DTD Entity Resolution XML Catalog V1.0//EN"
2742 "http://www.oasis-open.org/committees/entity/release/1.0/catalog.dtd"&gt;
2743&lt;catalog xmlns="urn:oasis:names:tc:entity:xmlns:xml:catalog"&gt;
2744 &lt;public publicId="-//OASIS//DTD DocBook XML V4.1.2//EN"
2745 uri="http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd"/&gt;
2746...</pre>
2747
2748<p>This is the beginning of a catalog for DocBook 4.1.2, XML Catalogs are
2749written in XML, there is a specific namespace for catalog elements
2750"urn:oasis:names:tc:entity:xmlns:xml:catalog". The first entry in this
2751catalog is a <code>public</code> mapping it allows to associate a Public
2752Identifier with an URI.</p>
2753<pre>...
2754 &lt;rewriteSystem systemIdStartString="http://www.oasis-open.org/docbook/"
2755 rewritePrefix="file:///usr/share/xml/docbook/"/&gt;
2756...</pre>
2757
2758<p>A <code>rewriteSystem</code> is a very powerful instruction, it says that
2759any URI starting with a given prefix should be looked at another URI
2760constructed by replacing the prefix with an new one. In effect this acts like
2761a cache system for a full area of the Web. In practice it is extremely useful
2762with a file prefix if you have installed a copy of those resources on your
2763local system.</p>
2764<pre>...
2765&lt;delegatePublic publicIdStartString="-//OASIS//DTD XML Catalog //"
2766 catalog="file:///usr/share/xml/docbook.xml"/&gt;
2767&lt;delegatePublic publicIdStartString="-//OASIS//ENTITIES DocBook XML"
2768 catalog="file:///usr/share/xml/docbook.xml"/&gt;
2769&lt;delegatePublic publicIdStartString="-//OASIS//DTD DocBook XML"
2770 catalog="file:///usr/share/xml/docbook.xml"/&gt;
2771&lt;delegateSystem systemIdStartString="http://www.oasis-open.org/docbook/"
2772 catalog="file:///usr/share/xml/docbook.xml"/&gt;
2773&lt;delegateURI uriStartString="http://www.oasis-open.org/docbook/"
2774 catalog="file:///usr/share/xml/docbook.xml"/&gt;
2775...</pre>
2776
2777<p>Delegation is the core features which allows to build a tree of catalogs,
2778easier to maintain than a single catalog, based on Public Identifier, System
2779Identifier or URI prefixes it instructs the catalog software to look up
2780entries in another resource. This feature allow to build hierarchies of
2781catalogs, the set of entries presented should be sufficient to redirect the
2782resolution of all DocBook references to the specific catalog in
2783<code>/usr/share/xml/docbook.xml</code> this one in turn could delegate all
2784references for DocBook 4.2.1 to a specific catalog installed at the same time
2785as the DocBook resources on the local machine.</p>
2786
2787<h3><a name="reference">How to tune catalog usage:</a></h3>
2788
2789<p>The user can change the default catalog behaviour by redirecting queries
2790to its own set of catalogs, this can be done by setting the
2791<code>XML_CATALOG_FILES</code> environment variable to a list of catalogs, an
2792empty one should deactivate loading the default <code>/etc/xml/catalog</code>
2793default catalog</p>
2794
2795<h3><a name="validate">How to debug catalog processing:</a></h3>
2796
2797<p>Setting up the <code>XML_DEBUG_CATALOG</code> environment variable will
2798make libxml output debugging informations for each catalog operations, for
2799example:</p>
2800<pre>orchis:~/XML -&gt; xmllint --memory --noout test/ent2
2801warning: failed to load external entity "title.xml"
2802orchis:~/XML -&gt; export XML_DEBUG_CATALOG=
2803orchis:~/XML -&gt; xmllint --memory --noout test/ent2
2804Failed to parse catalog /etc/xml/catalog
2805Failed to parse catalog /etc/xml/catalog
2806warning: failed to load external entity "title.xml"
2807Catalogs cleanup
2808orchis:~/XML -&gt; </pre>
2809
2810<p>The test/ent2 references an entity, running the parser from memory makes
2811the base URI unavailable and the the "title.xml" entity cannot be loaded.
2812Setting up the debug environment variable allows to detect that an attempt is
2813made to load the <code>/etc/xml/catalog</code> but since it's not present the
2814resolution fails.</p>
2815
2816<p>But the most advanced way to debug XML catalog processing is to use the
2817<strong>xmlcatalog</strong> command shipped with libxml2, it allows to load
2818catalogs and make resolution queries to see what is going on. This is also
2819used for the regression tests:</p>
2820<pre>orchis:~/XML -&gt; ./xmlcatalog test/catalogs/docbook.xml \
2821 "-//OASIS//DTD DocBook XML V4.1.2//EN"
2822http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd
2823orchis:~/XML -&gt; </pre>
2824
2825<p>For debugging what is going on, adding one -v flags increase the verbosity
2826level to indicate the processing done (adding a second flag also indicate
2827what elements are recognized at parsing):</p>
2828<pre>orchis:~/XML -&gt; ./xmlcatalog -v test/catalogs/docbook.xml \
2829 "-//OASIS//DTD DocBook XML V4.1.2//EN"
2830Parsing catalog test/catalogs/docbook.xml's content
2831Found public match -//OASIS//DTD DocBook XML V4.1.2//EN
2832http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd
2833Catalogs cleanup
2834orchis:~/XML -&gt; </pre>
2835
2836<p>A shell interface is also available to debug and process multiple queries
2837(and for regression tests):</p>
2838<pre>orchis:~/XML -&gt; ./xmlcatalog -shell test/catalogs/docbook.xml \
2839 "-//OASIS//DTD DocBook XML V4.1.2//EN"
2840&gt; help
2841Commands available:
2842public PublicID: make a PUBLIC identifier lookup
2843system SystemID: make a SYSTEM identifier lookup
2844resolve PublicID SystemID: do a full resolver lookup
2845add 'type' 'orig' 'replace' : add an entry
2846del 'values' : remove values
2847dump: print the current catalog state
2848debug: increase the verbosity level
2849quiet: decrease the verbosity level
2850exit: quit the shell
2851&gt; public "-//OASIS//DTD DocBook XML V4.1.2//EN"
2852http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd
2853&gt; quit
2854orchis:~/XML -&gt; </pre>
2855
2856<p>This should be sufficient for most debugging purpose, this was actually
2857used heavily to debug the XML Catalog implementation itself.</p>
2858
2859<h3><a name="Declaring">How to create and maintain</a> catalogs:</h3>
2860
2861<p>Basically XML Catalogs are XML files, you can either use XML tools to
2862manage them or use <strong>xmlcatalog</strong> for this. The basic step is
2863to create a catalog the -create option provide this facility:</p>
2864<pre>orchis:~/XML -&gt; ./xmlcatalog --create tst.xml
2865&lt;?xml version="1.0"?&gt;
2866&lt;!DOCTYPE catalog PUBLIC "-//OASIS//DTD Entity Resolution XML Catalog V1.0//EN"
2867 "http://www.oasis-open.org/committees/entity/release/1.0/catalog.dtd"&gt;
2868&lt;catalog xmlns="urn:oasis:names:tc:entity:xmlns:xml:catalog"/&gt;
2869orchis:~/XML -&gt; </pre>
2870
2871<p>By default xmlcatalog does not overwrite the original catalog and save the
2872result on the standard output, this can be overridden using the -noout
2873option. The <code>-add</code> command allows to add entries in the
2874catalog:</p>
2875<pre>orchis:~/XML -&gt; ./xmlcatalog --noout --create --add "public" \
2876 "-//OASIS//DTD DocBook XML V4.1.2//EN" \
2877 http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd tst.xml
2878orchis:~/XML -&gt; cat tst.xml
2879&lt;?xml version="1.0"?&gt;
2880&lt;!DOCTYPE catalog PUBLIC "-//OASIS//DTD Entity Resolution XML Catalog V1.0//EN" \
2881 "http://www.oasis-open.org/committees/entity/release/1.0/catalog.dtd"&gt;
2882&lt;catalog xmlns="urn:oasis:names:tc:entity:xmlns:xml:catalog"&gt;
2883&lt;public publicId="-//OASIS//DTD DocBook XML V4.1.2//EN"
2884 uri="http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd"/&gt;
2885&lt;/catalog&gt;
2886orchis:~/XML -&gt; </pre>
2887
2888<p>The <code>-add</code> option will always take 3 parameters even if some of
2889the XML Catalog constructs (like nextCatalog) will have only a single
2890argument, just pass a third empty string, it will be ignored.</p>
2891
2892<p>Similarly the <code>-del</code> option remove matching entries from the
2893catalog:</p>
2894<pre>orchis:~/XML -&gt; ./xmlcatalog --del \
2895 "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd" tst.xml
2896&lt;?xml version="1.0"?&gt;
2897&lt;!DOCTYPE catalog PUBLIC "-//OASIS//DTD Entity Resolution XML Catalog V1.0//EN"
2898 "http://www.oasis-open.org/committees/entity/release/1.0/catalog.dtd"&gt;
2899&lt;catalog xmlns="urn:oasis:names:tc:entity:xmlns:xml:catalog"/&gt;
2900orchis:~/XML -&gt; </pre>
2901
2902<p>The catalog is now empty. Note that the matching of <code>-del</code> is
2903exact and would have worked in a similar fashion with the Public ID
2904string.</p>
2905
2906<p>This is rudimentary but should be sufficient to manage a not too complex
2907catalog tree of resources.</p>
2908
2909<h3><a name="implemento">The implementor corner quick review of the
2910API:</a></h3>
2911
2912<p>First, and like for every other module of libxml, there is an
2913automatically generated <a href="html/libxml-catalog.html">API page for
2914catalog support</a>.</p>
2915
2916<p>The header for the catalog interfaces should be included as:</p>
2917<pre>#include &lt;libxml/catalog.h&gt;</pre>
2918
2919<p>The API is voluntarily kept very simple. First it is not obvious that
2920applications really need access to it since it is the default behaviour of
2921libxml (Note: it is possible to completely override libxml default catalog by
2922using <a href="html/libxml-parser.html">xmlSetExternalEntityLoader</a> to
2923plug an application specific resolver).</p>
2924
2925<p>Basically libxml support 2 catalog lists:</p>
2926<ul>
2927 <li>the default one, global shared by all the application</li>
2928 <li>a per-document catalog, this one is built if the document uses the
2929 <code>oasis-xml-catalog</code> PIs to specify its own catalog list, it is
2930 associated to the parser context and destroyed when the parsing context
2931 is destroyed.</li>
2932</ul>
2933
2934<p>the document one will be used first if it exists.</p>
2935
2936<h4>Initialization routines:</h4>
2937
2938<p>xmlInitializeCatalog(), xmlLoadCatalog() and xmlLoadCatalogs() should be
2939used at startup to initialize the catalog, if the catalog should be
2940initialized with specific values xmlLoadCatalog() or xmlLoadCatalogs()
2941should be called before xmlInitializeCatalog() which would otherwise do a
2942default initialization first.</p>
2943
2944<p>The xmlCatalogAddLocal() call is used by the parser to grow the document
2945own catalog list if needed.</p>
2946
2947<h4>Preferences setup:</h4>
2948
2949<p>The XML Catalog spec requires the possibility to select default
2950preferences between public and system delegation,
2951xmlCatalogSetDefaultPrefer() allows this, xmlCatalogSetDefaults() and
2952xmlCatalogGetDefaults() allow to control if XML Catalogs resolution should
2953be forbidden, allowed for global catalog, for document catalog or both, the
2954default is to allow both.</p>
2955
2956<p>And of course xmlCatalogSetDebug() allows to generate debug messages
2957(through the xmlGenericError() mechanism).</p>
2958
2959<h4>Querying routines:</h4>
2960
2961<p>xmlCatalogResolve(), xmlCatalogResolveSystem(), xmlCatalogResolvePublic()
2962and xmlCatalogResolveURI() are relatively explicit if you read the XML
2963Catalog specification they correspond to section 7 algorithms, they should
2964also work if you have loaded an SGML catalog with a simplified semantic.</p>
2965
2966<p>xmlCatalogLocalResolve() and xmlCatalogLocalResolveURI() are the same but
2967operate on the document catalog list</p>
2968
2969<h4>Cleanup and Miscellaneous:</h4>
2970
2971<p>xmlCatalogCleanup() free-up the global catalog, xmlCatalogFreeLocal() is
2972the per-document equivalent.</p>
2973
2974<p>xmlCatalogAdd() and xmlCatalogRemove() are used to dynamically modify the
2975first catalog in the global list, and xmlCatalogDump() allows to dump a
2976catalog state, those routines are primarily designed for xmlcatalog, I'm not
2977sure that exposing more complex interfaces (like navigation ones) would be
2978really useful.</p>
2979
2980<p>The xmlParseCatalogFile() is a function used to load XML Catalog files,
2981it's similar as xmlParseFile() except it bypass all catalog lookups, it's
2982provided because this functionality may be useful for client tools.</p>
2983
2984<h4>threaded environments:</h4>
2985
2986<p>Since the catalog tree is built progressively, some care has been taken to
2987try to avoid troubles in multithreaded environments. The code is now thread
2988safe assuming that the libxml library has been compiled with threads
2989support.</p>
2990
2991<p></p>
2992
2993<h3><a name="Other">Other resources</a></h3>
2994
2995<p>The XML Catalog specification is relatively recent so there isn't much
2996literature to point at:</p>
2997<ul>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]2998 <li>You can find a good rant from Norm Walsh about <a
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2999 href="http://www.arbortext.com/Think_Tank/XML_Resources/Issue_Three/issue_three.html">the
3000 need for catalogs</a>, it provides a lot of context informations even if
Daniel Veillard93d3a472002-04-26 14:04:55 +0000[diff] [blame]3001 I don't agree with everything presented. Norm also wrote a more recent
3002 article <a
3003 href="http://wwws.sun.com/software/xml/developers/resolver/article/">XML
3004 entities and URI resolvers</a> describing them.</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3005 <li>An <a href="http://home.ccil.org/~cowan/XML/XCatalog.html">old XML
3006 catalog proposal</a> from John Cowan</li>
3007 <li>The <a href="http://www.rddl.org/">Resource Directory Description
3008 Language</a> (RDDL) another catalog system but more oriented toward
3009 providing metadata for XML namespaces.</li>
3010 <li>the page from the OASIS Technical <a
3011 href="http://www.oasis-open.org/committees/entity/">Committee on Entity
3012 Resolution</a> who maintains XML Catalog, you will find pointers to the
3013 specification update, some background and pointers to others tools
3014 providing XML Catalog support</li>
Daniel Veillard35e937a2002-01-19 22:21:54 +0000[diff] [blame]3015 <li>Here is a <a href="buildDocBookCatalog">shell script</a> to generate
3016 XML Catalogs for DocBook 4.1.2 . If it can write to the /etc/xml/
3017 directory, it will set-up /etc/xml/catalog and /etc/xml/docbook based on
3018 the resources found on the system. Otherwise it will just create
3019 ~/xmlcatalog and ~/dbkxmlcatalog and doing:
Daniel Veillardc575b992002-02-08 13:28:40 +0000[diff] [blame]3020 <p><code>export XMLCATALOG=$HOME/xmlcatalog</code></p>
Daniel Veillard35e937a2002-01-19 22:21:54 +0000[diff] [blame]3021 <p>should allow to process DocBook documentations without requiring
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]3022 network accesses for the DTD or stylesheets</p>
Daniel Veillard35e937a2002-01-19 22:21:54 +0000[diff] [blame]3023 </li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3024 <li>I have uploaded <a href="ftp://xmlsoft.org/test/dbk412catalog.tar.gz">a
Daniel Veillard35e937a2002-01-19 22:21:54 +0000[diff] [blame]3025 small tarball</a> containing XML Catalogs for DocBook 4.1.2 which seems
3026 to work fine for me too</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3027 <li>The <a href="http://www.xmlsoft.org/xmlcatalog_man.html">xmlcatalog
3028 manual page</a></li>
3029</ul>
3030
3031<p>If you have suggestions for corrections or additions, simply contact
3032me:</p>
3033
3034<h2><a name="library">The parser interfaces</a></h2>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3035
3036<p>This section is directly intended to help programmers getting bootstrapped
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3037using the XML library from the C language. It is not intended to be
3038extensive. I hope the automatically generated documents will provide the
3039completeness required, but as a separate set of documents. The interfaces of
3040the XML library are by principle low level, there is nearly zero abstraction.
3041Those interested in a higher level API should <a href="#DOM">look at
3042DOM</a>.</p>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]3043
Daniel Veillard9cb5ff42001-01-29 08:22:21 +0000[diff] [blame]3044<p>The <a href="html/libxml-parser.html">parser interfaces for XML</a> are
3045separated from the <a href="html/libxml-htmlparser.html">HTML parser
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3046interfaces</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]3047
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3048<h3><a name="Invoking">Invoking the parser : the pull method</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3049
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3050<p>Usually, the first thing to do is to read an XML input. The parser accepts
3051documents either from in-memory strings or from files. The functions are
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3052defined in "parser.h":</p>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]3053<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3054 <dt><code>xmlDocPtr xmlParseMemory(char *buffer, int size);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3055 <dd><p>Parse a null-terminated string containing the document.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3056 </dd>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]3057</dl>
3058<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3059 <dt><code>xmlDocPtr xmlParseFile(const char *filename);</code></dt>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]3060 <dd><p>Parse an XML document contained in a (possibly compressed)
3061 file.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3062 </dd>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]3063</dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3064
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3065<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]3066failure).</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3067
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3068<h3 id="Invoking1">Invoking the parser: the push method</h3>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]3069
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3070<p>In order for the application to keep the control when the document is
3071being fetched (which is common for GUI based programs) libxml provides a push
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3072interface, too, as of version 1.8.3. Here are the interface functions:</p>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]3073<pre>xmlParserCtxtPtr xmlCreatePushParserCtxt(xmlSAXHandlerPtr sax,
3074 void *user_data,
3075 const char *chunk,
3076 int size,
3077 const char *filename);
3078int xmlParseChunk (xmlParserCtxtPtr ctxt,
3079 const char *chunk,
3080 int size,
3081 int terminate);</pre>
3082
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3083<p>and here is a simple example showing how to use the interface:</p>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]3084<pre> FILE *f;
3085
3086 f = fopen(filename, "r");
3087 if (f != NULL) {
3088 int res, size = 1024;
3089 char chars[1024];
3090 xmlParserCtxtPtr ctxt;
3091
3092 res = fread(chars, 1, 4, f);
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3093 if (res &gt; 0) {
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]3094 ctxt = xmlCreatePushParserCtxt(NULL, NULL,
3095 chars, res, filename);
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3096 while ((res = fread(chars, 1, size, f)) &gt; 0) {
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]3097 xmlParseChunk(ctxt, chars, res, 0);
3098 }
3099 xmlParseChunk(ctxt, chars, 0, 1);
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3100 doc = ctxt-&gt;myDoc;
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]3101 xmlFreeParserCtxt(ctxt);
3102 }
3103 }</pre>
3104
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]3105<p>The HTML parser embedded into libxml also has a push interface; the
3106functions are just prefixed by "html" rather than "xml".</p>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]3107
3108<h3 id="Invoking2">Invoking the parser: the SAX interface</h3>
3109
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]3110<p>The tree-building interface makes the parser memory-hungry, first loading
3111the document in memory and then building the tree itself. Reading a document
3112without building the tree is possible using the SAX interfaces (see SAX.h and
3113<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]3114Henstridge's documentation</a>). Note also that the push interface can be
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3115limited to SAX: just use the two first arguments of
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]3116<code>xmlCreatePushParserCtxt()</code>.</p>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]3117
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]3118<h3><a name="Building">Building a tree from scratch</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3119
3120<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]3121there is a set of functions dedicated to building new elements. (These are
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3122also described in &lt;libxml/tree.h&gt;.) For example, here is a piece of
3123code that produces the XML document used in the previous examples:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3124<pre> #include &lt;libxml/tree.h&gt;
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]3125 xmlDocPtr doc;
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3126 xmlNodePtr tree, subtree;
3127
3128 doc = xmlNewDoc("1.0");
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3129 doc-&gt;children = xmlNewDocNode(doc, NULL, "EXAMPLE", NULL);
3130 xmlSetProp(doc-&gt;children, "prop1", "gnome is great");
3131 xmlSetProp(doc-&gt;children, "prop2", "&amp; linux too");
3132 tree = xmlNewChild(doc-&gt;children, NULL, "head", NULL);
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3133 subtree = xmlNewChild(tree, NULL, "title", "Welcome to Gnome");
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3134 tree = xmlNewChild(doc-&gt;children, NULL, "chapter", NULL);
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3135 subtree = xmlNewChild(tree, NULL, "title", "The Linux adventure");
3136 subtree = xmlNewChild(tree, NULL, "p", "bla bla bla ...");
3137 subtree = xmlNewChild(tree, NULL, "image", NULL);
3138 xmlSetProp(subtree, "href", "linus.gif");</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3139
3140<p>Not really rocket science ...</p>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3141
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]3142<h3><a name="Traversing">Traversing the tree</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3143
Daniel Veillard9cb5ff42001-01-29 08:22:21 +0000[diff] [blame]3144<p>Basically by <a href="html/libxml-tree.html">including "tree.h"</a> your
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3145code has access to the internal structure of all the elements of the tree.
3146The names should be somewhat simple like <strong>parent</strong>,
Daniel Veillard306be992000-07-03 12:38:45 +0000[diff] [blame]3147<strong>children</strong>, <strong>next</strong>, <strong>prev</strong>,
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3148<strong>properties</strong>, etc... For example, still with the previous
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]3149example:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3150<pre><code>doc-&gt;children-&gt;children-&gt;children</code></pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3151
3152<p>points to the title element,</p>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3153<pre>doc-&gt;children-&gt;children-&gt;next-&gt;children-&gt;children</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3154
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]3155<p>points to the text node containing the chapter title "The Linux
3156adventure".</p>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]3157
Daniel Veillardb24054a1999-12-18 15:32:46 +0000[diff] [blame]3158<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]3159present before the document root, so <code>doc-&gt;children</code> may point
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3160to an element which is not the document Root Element; a function
Daniel Veillard5cb5ab81999-12-21 15:35:29 +0000[diff] [blame]3161<code>xmlDocGetRootElement()</code> was added for this purpose.</p>
Daniel Veillardb24054a1999-12-18 15:32:46 +0000[diff] [blame]3162
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]3163<h3><a name="Modifying">Modifying the tree</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3164
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3165<p>Functions are provided for reading and writing the document content. Here
Daniel Veillard9cb5ff42001-01-29 08:22:21 +0000[diff] [blame]3166is an excerpt from the <a href="html/libxml-tree.html">tree API</a>:</p>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3167<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +0000[diff] [blame]3168 <dt><code>xmlAttrPtr xmlSetProp(xmlNodePtr node, const xmlChar *name, const
3169 xmlChar *value);</code></dt>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3170 <dd><p>This sets (or changes) an attribute carried by an ELEMENT node.
3171 The value can be NULL.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3172 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3173</dl>
3174<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +0000[diff] [blame]3175 <dt><code>const xmlChar *xmlGetProp(xmlNodePtr node, const xmlChar
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3176 *name);</code></dt>
Daniel Veillardc92c3042000-09-29 02:42:04 +0000[diff] [blame]3177 <dd><p>This function returns a pointer to new copy of the property
3178 content. Note that the user must deallocate the result.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3179 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3180</dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3181
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3182<p>Two functions are provided for reading and writing the text associated
3183with elements:</p>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3184<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +0000[diff] [blame]3185 <dt><code>xmlNodePtr xmlStringGetNodeList(xmlDocPtr doc, const xmlChar
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3186 *value);</code></dt>
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]3187 <dd><p>This function takes an "external" string and converts it to one
3188 text node or possibly to a list of entity and text nodes. All
3189 non-predefined entity references like &amp;Gnome; will be stored
3190 internally as entity nodes, hence the result of the function may not be
3191 a single node.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3192 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3193</dl>
3194<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +0000[diff] [blame]3195 <dt><code>xmlChar *xmlNodeListGetString(xmlDocPtr doc, xmlNodePtr list, int
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3196 inLine);</code></dt>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]3197 <dd><p>This function is the inverse of
3198 <code>xmlStringGetNodeList()</code>. It generates a new string
3199 containing the content of the text and entity nodes. Note the extra
3200 argument inLine. If this argument is set to 1, the function will expand
3201 entity references. For example, instead of returning the &amp;Gnome;
3202 XML encoding in the string, it will substitute it with its value (say,
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3203 "GNU Network Object Model Environment").</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3204 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3205</dl>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]3206
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]3207<h3><a name="Saving">Saving a tree</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3208
3209<p>Basically 3 options are possible:</p>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3210<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +0000[diff] [blame]3211 <dt><code>void xmlDocDumpMemory(xmlDocPtr cur, xmlChar**mem, int
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3212 *size);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3213 <dd><p>Returns a buffer into which the document has been saved.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3214 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3215</dl>
3216<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3217 <dt><code>extern void xmlDocDump(FILE *f, xmlDocPtr doc);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3218 <dd><p>Dumps a document to an open file descriptor.</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>int xmlSaveFile(const char *filename, xmlDocPtr cur);</code></dt>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]3223 <dd><p>Saves the document to a file. In this case, the compression
3224 interface is triggered if it has been turned on.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3225 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3226</dl>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]3227
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]3228<h3><a name="Compressio">Compression</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3229
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3230<p>The library transparently handles compression when doing file-based
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]3231accesses. The level of compression on saves can be turned on either globally
3232or individually for one file:</p>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3233<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3234 <dt><code>int xmlGetDocCompressMode (xmlDocPtr doc);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3235 <dd><p>Gets the document compression ratio (0-9).</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3236 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3237</dl>
3238<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3239 <dt><code>void xmlSetDocCompressMode (xmlDocPtr doc, int mode);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3240 <dd><p>Sets the document compression ratio.</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>int xmlGetCompressMode(void);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3245 <dd><p>Gets the default 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>void xmlSetCompressMode(int mode);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3250 <dd><p>Sets 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
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]3254<h2><a name="Entities">Entities or no entities</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3255
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3256<p>Entities in principle are similar to simple C macros. An entity defines an
3257abbreviation for a given string that you can reuse many times throughout the
3258content of your document. Entities are especially useful when a given string
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]3259may occur frequently within a document, or to confine the change needed to a
3260document to a restricted area in the internal subset of the document (at the
3261beginning). Example:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3262<pre>1 &lt;?xml version="1.0"?&gt;
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]32632 &lt;!DOCTYPE EXAMPLE SYSTEM "example.dtd" [
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]32643 &lt;!ENTITY xml "Extensible Markup Language"&gt;
32654 ]&gt;
32665 &lt;EXAMPLE&gt;
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]32676 &amp;xml;
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]32687 &lt;/EXAMPLE&gt;</pre>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3269
3270<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]3271its name with '&amp;' and following it by ';' without any spaces added. There
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]3272are 5 predefined entities in libxml allowing you to escape characters with
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3273predefined meaning in some parts of the xml document content:
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3274<strong>&amp;lt;</strong> for the character '&lt;', <strong>&amp;gt;</strong>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3275for the character '&gt;', <strong>&amp;apos;</strong> for the character ''',
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3276<strong>&amp;quot;</strong> for the character '"', and
3277<strong>&amp;amp;</strong> for the character '&amp;'.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3278
3279<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]3280substitute an entity's content so that you can see the replacement text in
3281your application. Or you may prefer to keep entity references as such in the
3282content to be able to save the document back without losing this usually
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3283precious information (if the user went through the pain of explicitly
3284defining entities, he may have a a rather negative attitude if you blindly
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]3285substitute them as saving time). The <a
Daniel Veillard9cb5ff42001-01-29 08:22:21 +0000[diff] [blame]3286href="html/libxml-parser.html#XMLSUBSTITUTEENTITIESDEFAULT">xmlSubstituteEntitiesDefault()</a>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3287function allows you to check and change the behaviour, which is to not
3288substitute entities by default.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3289
3290<p>Here is the DOM tree built by libxml for the previous document in the
3291default case:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3292<pre>/gnome/src/gnome-xml -&gt; ./xmllint --debug test/ent1
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3293DOCUMENT
3294version=1.0
3295 ELEMENT EXAMPLE
3296 TEXT
3297 content=
3298 ENTITY_REF
3299 INTERNAL_GENERAL_ENTITY xml
3300 content=Extensible Markup Language
3301 TEXT
3302 content=</pre>
3303
3304<p>And here is the result when substituting entities:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3305<pre>/gnome/src/gnome-xml -&gt; ./tester --debug --noent test/ent1
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3306DOCUMENT
3307version=1.0
3308 ELEMENT EXAMPLE
3309 TEXT
3310 content= Extensible Markup Language</pre>
3311
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3312<p>So, entities or no entities? Basically, it depends on your use case. I
3313suggest that you keep the non-substituting default behaviour and avoid using
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3314entities in your XML document or data if you are not willing to handle the
3315entity references elements in the DOM tree.</p>
3316
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3317<p>Note that at save time libxml enforces the conversion of the predefined
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3318entities where necessary to prevent well-formedness problems, and will also
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3319transparently replace those with chars (i.e. it will not generate entity
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3320reference elements in the DOM tree or call the reference() SAX callback when
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3321finding them in the input).</p>
3322
Daniel Veillard7b9c4b72000-08-25 16:26:50 +0000[diff] [blame]3323<p><span style="background-color: #FF0000">WARNING</span>: handling entities
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3324on top of the libxml SAX interface is difficult!!! If you plan to use
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]3325non-predefined entities in your documents, then the learning curve to handle
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3326then 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]3327strongly suggest you consider using the DOM interface instead and let libxml
Daniel Veillard8c6d6af2000-08-25 17:14:13 +0000[diff] [blame]3328deal with the complexity rather than trying to do it yourself.</p>
Daniel Veillard7b9c4b72000-08-25 16:26:50 +0000[diff] [blame]3329
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]3330<h2><a name="Namespaces">Namespaces</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3331
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]3332<p>The libxml library implements <a
3333href="http://www.w3.org/TR/REC-xml-names/">XML namespaces</a> support by
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]3334recognizing namespace constructs in the input, and does namespace lookup
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]3335automatically when building the DOM tree. A namespace declaration is
3336associated with an in-memory structure and all elements or attributes within
3337that namespace point to it. Hence testing the namespace is a simple and fast
3338equality operation at the user level.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3339
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]3340<p>I suggest that people using libxml use a namespace, and declare it in the
3341root element of their document as the default namespace. Then they don't need
3342to 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]3343refinement and merging of data from different sources. This doesn't increase
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]3344the size of the XML output significantly, but significantly increases its
3345value in the long-term. Example:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3346<pre>&lt;mydoc xmlns="http://mydoc.example.org/schemas/"&gt;
3347 &lt;elem1&gt;...&lt;/elem1&gt;
3348 &lt;elem2&gt;...&lt;/elem2&gt;
3349&lt;/mydoc&gt;</pre>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3350
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]3351<p>The namespace value has to be an absolute URL, but the URL doesn't have to
3352point to any existing resource on the Web. It will bind all the element and
Daniel Veillardc0801af2002-05-28 16:28:42 +0000[diff] [blame^]3353attributes with that URL. I suggest to use an URL within a domain you
3354control, and that the URL should contain some kind of version information if
3355possible. For example, <code>"http://www.gnome.org/gnumeric/1.0/"</code> is a
3356good namespace scheme.</p>
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]3357
3358<p>Then when you load a file, make sure that a namespace carrying the
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3359version-independent prefix is installed on the root element of your document,
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3360and if the version information don't match something you know, warn the user
3361and 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]3362namespace checking on the prefix value. &lt;foo:text&gt; may be exactly the
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3363same as &lt;bar:text&gt; in another document. What really matters is the URI
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3364associated with the element or the attribute, not the prefix string (which is
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3365just a shortcut for the full URI). In libxml, element and attributes have an
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]3366<code>ns</code> field pointing to an xmlNs structure detailing the namespace
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3367prefix and its URI.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3368
3369<p>@@Interfaces@@</p>
3370
3371<p>@@Examples@@</p>
3372
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3373<p>Usually people object to using namespaces together with validity checking.
3374I will try to make sure that using namespaces won't break validity checking,
3375so even if you plan to use or currently are using validation I strongly
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]3376suggest adding namespaces to your document. A default namespace scheme
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3377<code>xmlns="http://...."</code> should not break validity even on less
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3378flexible parsers. Using namespaces to mix and differentiate content coming
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3379from multiple DTDs will certainly break current validation schemes. I will
3380try to provide ways to do this, but this may not be portable or
3381standardized.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3382
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3383<h2><a name="Upgrading">Upgrading 1.x code</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3384
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3385<p>Incompatible changes:</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3386
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3387<p>Version 2 of libxml is the first version introducing serious backward
3388incompatible changes. The main goals were:</p>
3389<ul>
3390 <li>a general cleanup. A number of mistakes inherited from the very early
3391 versions couldn't be changed due to compatibility constraints. Example
3392 the "childs" element in the nodes.</li>
3393 <li>Uniformization of the various nodes, at least for their header and link
3394 parts (doc, parent, children, prev, next), the goal is a simpler
3395 programming model and simplifying the task of the DOM implementors.</li>
3396 <li>better conformances to the XML specification, for example version 1.x
3397 had an heuristic to try to detect ignorable white spaces. As a result the
3398 SAX event generated were ignorableWhitespace() while the spec requires
3399 character() in that case. This also mean that a number of DOM node
3400 containing blank text may populate the DOM tree which were not present
3401 before.</li>
3402</ul>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3403
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3404<h3>How to fix libxml-1.x code:</h3>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3405
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3406<p>So client code of libxml designed to run with version 1.x may have to be
3407changed to compile against version 2.x of libxml. Here is a list of changes
3408that I have collected, they may not be sufficient, so in case you find other
3409change which are required, <a href="mailto:Daniel.Ïeillardw3.org">drop me a
3410mail</a>:</p>
3411<ol>
3412 <li>The package name have changed from libxml to libxml2, the library name
3413 is now -lxml2 . There is a new xml2-config script which should be used to
3414 select the right parameters libxml2</li>
3415 <li>Node <strong>childs</strong> field has been renamed
3416 <strong>children</strong> so s/childs/children/g should be applied
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]3417 (probability of having "childs" anywhere else is close to 0+</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3418 <li>The document don't have anymore a <strong>root</strong> element it has
3419 been replaced by <strong>children</strong> and usually you will get a
3420 list of element here. For example a Dtd element for the internal subset
3421 and it's declaration may be found in that list, as well as processing
3422 instructions or comments found before or after the document root element.
3423 Use <strong>xmlDocGetRootElement(doc)</strong> to get the root element of
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]3424 a document. Alternatively if you are sure to not reference DTDs nor have
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3425 PIs or comments before or after the root element
3426 s/-&gt;root/-&gt;children/g will probably do it.</li>
3427 <li>The white space issue, this one is more complex, unless special case of
3428 validating parsing, the line breaks and spaces usually used for indenting
3429 and formatting the document content becomes significant. So they are
3430 reported by SAX and if your using the DOM tree, corresponding nodes are
3431 generated. Too approach can be taken:
3432 <ol>
3433 <li>lazy one, use the compatibility call
3434 <strong>xmlKeepBlanksDefault(0)</strong> but be aware that you are
3435 relying on a special (and possibly broken) set of heuristics of
3436 libxml to detect ignorable blanks. Don't complain if it breaks or
3437 make your application not 100% clean w.r.t. to it's input.</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]3438 <li>the Right Way: change you code to accept possibly insignificant
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3439 blanks characters, or have your tree populated with weird blank text
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]3440 nodes. You can spot them using the commodity function
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3441 <strong>xmlIsBlankNode(node)</strong> returning 1 for such blank
3442 nodes.</li>
3443 </ol>
3444 <p>Note also that with the new default the output functions don't add any
3445 extra indentation when saving a tree in order to be able to round trip
3446 (read and save) without inflating the document with extra formatting
3447 chars.</p>
3448 </li>
3449 <li>The include path has changed to $prefix/libxml/ and the includes
3450 themselves uses this new prefix in includes instructions... If you are
3451 using (as expected) the
3452 <pre>xml2-config --cflags</pre>
3453 <p>output to generate you compile commands this will probably work out of
3454 the box</p>
3455 </li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]3456 <li>xmlDetectCharEncoding takes an extra argument indicating the length in
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3457 byte of the head of the document available for character detection.</li>
3458</ol>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3459
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3460<h3>Ensuring both libxml-1.x and libxml-2.x compatibility</h3>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3461
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3462<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]3463to allow smooth upgrade of existing libxml v1code while retaining
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3464compatibility. They offers the following:</p>
3465<ol>
3466 <li>similar include naming, one should use
3467 <strong>#include&lt;libxml/...&gt;</strong> in both cases.</li>
3468 <li>similar identifiers defined via macros for the child and root fields:
3469 respectively <strong>xmlChildrenNode</strong> and
3470 <strong>xmlRootNode</strong></li>
3471 <li>a new macro <strong>LIBXML_TEST_VERSION</strong> which should be
3472 inserted once in the client code</li>
3473</ol>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3474
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3475<p>So the roadmap to upgrade your existing libxml applications is the
3476following:</p>
3477<ol>
3478 <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]3479 <li>find all occurrences where the xmlDoc <strong>root</strong> field is
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3480 used and change it to <strong>xmlRootNode</strong></li>
Daniel Veillardc0801af2002-05-28 16:28:42 +0000[diff] [blame^]3481 <li>similarly find all occurrences where the xmlNode
3482 <strong>childs</strong> field is used and change it to
3483 <strong>xmlChildrenNode</strong></li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3484 <li>add a <strong>LIBXML_TEST_VERSION</strong> macro somewhere in your
3485 <strong>main()</strong> or in the library init entry point</li>
3486 <li>Recompile, check compatibility, it should still work</li>
Daniel Veillardc0801af2002-05-28 16:28:42 +0000[diff] [blame^]3487 <li>Change your configure script to look first for xml2-config and fall
3488 back using xml-config . Use the --cflags and --libs output of the command
3489 as the Include and Linking parameters needed to use libxml.</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3490 <li>install libxml2-2.3.x and libxml2-devel-2.3.x (libxml-1.8.y and
3491 libxml-devel-1.8.y can be kept simultaneously)</li>
3492 <li>remove your config.cache, relaunch your configuration mechanism, and
3493 recompile, if steps 2 and 3 were done right it should compile as-is</li>
3494 <li>Test that your application is still running correctly, if not this may
3495 be due to extra empty nodes due to formating spaces being kept in libxml2
3496 contrary to libxml1, in that case insert xmlKeepBlanksDefault(1) in your
3497 code before calling the parser (next to
3498 <strong>LIBXML_TEST_VERSION</strong> is a fine place).</li>
3499</ol>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3500
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3501<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]3502
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3503<p>Let me put some emphasis on the fact that there is far more changes from
3504libxml 1.x to 2.x than the ones you may have to patch for. The overall code
3505has been considerably cleaned up and the conformance to the XML specification
3506has been drastically improved too. Don't take those changes as an excuse to
3507not upgrade, it may cost a lot on the long term ...</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3508
Daniel Veillard52dcab32001-10-30 12:51:17 +0000[diff] [blame]3509<h2><a name="Thread">Thread safety</a></h2>
3510
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]3511<p>Starting with 2.4.7, libxml makes provisions to ensure that concurrent
Daniel Veillard52dcab32001-10-30 12:51:17 +0000[diff] [blame]3512threads can safely work in parallel parsing different documents. There is
3513however a couple of things to do to ensure it:</p>
3514<ul>
3515 <li>configure the library accordingly using the --with-threads options</li>
3516 <li>call xmlInitParser() in the "main" thread before using any of the
3517 libxml API (except possibly selecting a different memory allocator)</li>
3518</ul>
3519
3520<p>Note that the thread safety cannot be ensured for multiple threads sharing
3521the same document, the locking must be done at the application level, libxml
3522exports a basic mutex and reentrant mutexes API in &lt;libxml/threads.h&gt;.
3523The parts of the library checked for thread safety are:</p>
3524<ul>
3525 <li>concurrent loading</li>
3526 <li>file access resolution</li>
3527 <li>catalog access</li>
3528 <li>catalog building</li>
3529 <li>entities lookup/accesses</li>
3530 <li>validation</li>
3531 <li>global variables per-thread override</li>
3532 <li>memory handling</li>
3533</ul>
3534
3535<p>XPath is supposed to be thread safe now, but this wasn't tested
3536seriously.</p>
3537
Daniel Veillard35008381999-10-25 13:15:52 +0000[diff] [blame]3538<h2><a name="DOM"></a><a name="Principles">DOM Principles</a></h2>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3539
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3540<p><a href="http://www.w3.org/DOM/">DOM</a> stands for the <em>Document
3541Object Model</em>; this is an API for accessing XML or HTML structured
3542documents. Native support for DOM in Gnome is on the way (module gnome-dom),
3543and will be based on gnome-xml. This will be a far cleaner interface to
3544manipulate XML files within Gnome since it won't expose the internal
3545structure.</p>
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3546
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3547<p>The current DOM implementation on top of libxml is the <a
Daniel Veillarda47fb3d2001-03-25 17:23:49 +0000[diff] [blame]3548href="http://cvs.gnome.org/lxr/source/gdome2/">gdome2 Gnome module</a>, this
3549is a full DOM interface, thanks to Paolo Casarini, check the <a
3550href="http://www.cs.unibo.it/~casarini/gdome2/">Gdome2 homepage</a> for more
3551informations.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3552
Daniel Veillard35008381999-10-25 13:15:52 +0000[diff] [blame]3553<h2><a name="Example"></a><a name="real">A real example</a></h2>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3554
3555<p>Here is a real size example, where the actual content of the application
3556data 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]3557a proposal to keep a database of jobs related to Gnome, with an XML based
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3558storage structure. Here is an <a href="gjobs.xml">XML encoded jobs
3559base</a>:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3560<pre>&lt;?xml version="1.0"?&gt;
3561&lt;gjob:Helping xmlns:gjob="http://www.gnome.org/some-location"&gt;
3562 &lt;gjob:Jobs&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3563
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3564 &lt;gjob:Job&gt;
3565 &lt;gjob:Project ID="3"/&gt;
3566 &lt;gjob:Application&gt;GBackup&lt;/gjob:Application&gt;
3567 &lt;gjob:Category&gt;Development&lt;/gjob:Category&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:Update&gt;
3570 &lt;gjob:Status&gt;Open&lt;/gjob:Status&gt;
3571 &lt;gjob:Modified&gt;Mon, 07 Jun 1999 20:27:45 -0400 MET DST&lt;/gjob:Modified&gt;
3572 &lt;gjob:Salary&gt;USD 0.00&lt;/gjob:Salary&gt;
3573 &lt;/gjob:Update&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3574
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3575 &lt;gjob:Developers&gt;
3576 &lt;gjob:Developer&gt;
3577 &lt;/gjob:Developer&gt;
3578 &lt;/gjob:Developers&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:Contact&gt;
3581 &lt;gjob:Person&gt;Nathan Clemons&lt;/gjob:Person&gt;
3582 &lt;gjob:Email&gt;nathan@windsofstorm.net&lt;/gjob:Email&gt;
3583 &lt;gjob:Company&gt;
3584 &lt;/gjob:Company&gt;
3585 &lt;gjob:Organisation&gt;
3586 &lt;/gjob:Organisation&gt;
3587 &lt;gjob:Webpage&gt;
3588 &lt;/gjob:Webpage&gt;
3589 &lt;gjob:Snailmail&gt;
3590 &lt;/gjob:Snailmail&gt;
3591 &lt;gjob:Phone&gt;
3592 &lt;/gjob:Phone&gt;
3593 &lt;/gjob:Contact&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3594
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3595 &lt;gjob:Requirements&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3596 The program should be released as free software, under the GPL.
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3597 &lt;/gjob:Requirements&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3598
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3599 &lt;gjob:Skills&gt;
3600 &lt;/gjob:Skills&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3601
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3602 &lt;gjob:Details&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3603 A GNOME based system that will allow a superuser to configure
3604 compressed and uncompressed files and/or file systems to be backed
3605 up with a supported media in the system. This should be able to
3606 perform via find commands generating a list of files that are passed
3607 to tar, dd, cpio, cp, gzip, etc., to be directed to the tape machine
3608 or via operations performed on the filesystem itself. Email
3609 notification and GUI status display very important.
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3610 &lt;/gjob:Details&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3611
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3612 &lt;/gjob:Job&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3613
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3614 &lt;/gjob:Jobs&gt;
3615&lt;/gjob:Helping&gt;</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3616
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3617<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]3618calling only a couple of functions, browsing the tree to gather the data and
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3619generate the internal structures is harder, and more error prone.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3620
3621<p>The suggested principle is to be tolerant with respect to the input
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3622structure. For example, the ordering of the attributes is not significant,
3623the 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]3624depend on the order of the children of a given node, unless it really makes
3625things harder. Here is some code to parse the information for a person:</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3626<pre>/*
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3627 * A person record
3628 */
3629typedef struct person {
3630 char *name;
3631 char *email;
3632 char *company;
3633 char *organisation;
3634 char *smail;
3635 char *webPage;
3636 char *phone;
3637} person, *personPtr;
3638
3639/*
3640 * And the code needed to parse it
3641 */
3642personPtr parsePerson(xmlDocPtr doc, xmlNsPtr ns, xmlNodePtr cur) {
3643 personPtr ret = NULL;
3644
3645DEBUG("parsePerson\n");
3646 /*
3647 * allocate the struct
3648 */
3649 ret = (personPtr) malloc(sizeof(person));
3650 if (ret == NULL) {
3651 fprintf(stderr,"out of memory\n");
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3652 return(NULL);
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3653 }
3654 memset(ret, 0, sizeof(person));
3655
3656 /* We don't care what the top level element name is */
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3657 cur = cur-&gt;xmlChildrenNode;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3658 while (cur != NULL) {
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3659 if ((!strcmp(cur-&gt;name, "Person")) &amp;&amp; (cur-&gt;ns == ns))
3660 ret-&gt;name = xmlNodeListGetString(doc, cur-&gt;xmlChildrenNode, 1);
3661 if ((!strcmp(cur-&gt;name, "Email")) &amp;&amp; (cur-&gt;ns == ns))
3662 ret-&gt;email = xmlNodeListGetString(doc, cur-&gt;xmlChildrenNode, 1);
3663 cur = cur-&gt;next;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3664 }
3665
3666 return(ret);
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3667}</pre>
3668
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3669<p>Here are a couple of things to notice:</p>
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3670<ul>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3671 <li>Usually a recursive parsing style is the more convenient one: XML data
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]3672 is by nature subject to repetitive constructs and usually exhibits highly
3673 structured patterns.</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3674 <li>The two arguments of type <em>xmlDocPtr</em> and <em>xmlNsPtr</em>,
3675 i.e. the pointer to the global XML document and the namespace reserved to
3676 the application. Document wide information are needed for example to
3677 decode entities and it's a good coding practice to define a namespace for
3678 your application set of data and test that the element and attributes
3679 you're analyzing actually pertains to your application space. This is
3680 done by a simple equality test (cur-&gt;ns == ns).</li>
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]3681 <li>To retrieve text and attributes value, you can use the function
3682 <em>xmlNodeListGetString</em> to gather all the text and entity reference
3683 nodes generated by the DOM output and produce an single text string.</li>
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3684</ul>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3685
3686<p>Here is another piece of code used to parse another level of the
3687structure:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3688<pre>#include &lt;libxml/tree.h&gt;
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]3689/*
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3690 * a Description for a Job
3691 */
3692typedef struct job {
3693 char *projectID;
3694 char *application;
3695 char *category;
3696 personPtr contact;
3697 int nbDevelopers;
3698 personPtr developers[100]; /* using dynamic alloc is left as an exercise */
3699} job, *jobPtr;
3700
3701/*
3702 * And the code needed to parse it
3703 */
3704jobPtr parseJob(xmlDocPtr doc, xmlNsPtr ns, xmlNodePtr cur) {
3705 jobPtr ret = NULL;
3706
3707DEBUG("parseJob\n");
3708 /*
3709 * allocate the struct
3710 */
3711 ret = (jobPtr) malloc(sizeof(job));
3712 if (ret == NULL) {
3713 fprintf(stderr,"out of memory\n");
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3714 return(NULL);
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3715 }
3716 memset(ret, 0, sizeof(job));
3717
3718 /* We don't care what the top level element name is */
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3719 cur = cur-&gt;xmlChildrenNode;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3720 while (cur != NULL) {
3721
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3722 if ((!strcmp(cur-&gt;name, "Project")) &amp;&amp; (cur-&gt;ns == ns)) {
3723 ret-&gt;projectID = xmlGetProp(cur, "ID");
3724 if (ret-&gt;projectID == NULL) {
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3725 fprintf(stderr, "Project has no ID\n");
3726 }
3727 }
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3728 if ((!strcmp(cur-&gt;name, "Application")) &amp;&amp; (cur-&gt;ns == ns))
3729 ret-&gt;application = xmlNodeListGetString(doc, cur-&gt;xmlChildrenNode, 1);
3730 if ((!strcmp(cur-&gt;name, "Category")) &amp;&amp; (cur-&gt;ns == ns))
3731 ret-&gt;category = xmlNodeListGetString(doc, cur-&gt;xmlChildrenNode, 1);
3732 if ((!strcmp(cur-&gt;name, "Contact")) &amp;&amp; (cur-&gt;ns == ns))
3733 ret-&gt;contact = parsePerson(doc, ns, cur);
3734 cur = cur-&gt;next;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3735 }
3736
3737 return(ret);
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3738}</pre>
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3739
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]3740<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]3741boring. Ultimately, it could be possible to write stubbers taking either C
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3742data structure definitions, a set of XML examples or an XML DTD and produce
3743the code needed to import and export the content between C data and XML
3744storage. This is left as an exercise to the reader :-)</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3745
Daniel Veillard6f0adb52000-07-03 11:41:26 +0000[diff] [blame]3746<p>Feel free to use <a href="example/gjobread.c">the code for the full C
3747parsing example</a> as a template, it is also available with Makefile in the
3748Gnome CVS base under gnome-xml/example</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3749
Daniel Veillardc310d562000-06-23 18:32:15 +0000[diff] [blame]3750<h2><a name="Contributi">Contributions</a></h2>
3751<ul>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3752 <li>Bjorn Reese, William Brack and Thomas Broyer have provided a number of
3753 patches, Gary Pennington worked on the validation API, threading support
3754 and Solaris port.</li>
3755 <li>John Fleck helps maintaining the documentation and man pages.</li>
Daniel Veillardb2fb8ed2002-04-01 09:33:12 +0000[diff] [blame]3756 <li><a href="mailto:igor@stud.fh-frankfurt.de">Igor Zlatkovic</a> is now
3757 the maintainer of the Windows port, <a
Daniel Veillard95189532001-07-26 18:30:26 +0000[diff] [blame]3758 href="http://www.fh-frankfurt.de/~igor/projects/libxml/index.html">he
3759 provides binaries</a></li>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]3760 <li><a href="mailto:Gary.Pennington@sun.com">Gary Pennington</a> provides
3761 <a href="http://garypennington.net/libxml2/">Solaris binaries</a></li>
Daniel Veillarde356c282001-03-10 12:32:04 +0000[diff] [blame]3762 <li><a
3763 href="http://mail.gnome.org/archives/xml/2001-March/msg00014.html">Matt
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]3764 Sergeant</a> developed <a
3765 href="http://axkit.org/download/">XML::LibXSLT</a>, a Perl wrapper for
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]3766 libxml2/libxslt as part of the <a href="http://axkit.com/">AxKit XML
3767 application server</a></li>
3768 <li><a href="mailto:fnatter@gmx.net">Felix Natter</a> and <a
3769 href="mailto:geertk@ai.rug.nl">Geert Kloosterman</a> provide <a
Daniel Veillardca989762001-06-23 17:39:29 +0000[diff] [blame]3770 href="libxml-doc.el">an emacs module</a> to lookup libxml(2) functions
Daniel Veillard3f6f7f62000-06-30 17:58:25 +0000[diff] [blame]3771 documentation</li>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]3772 <li><a href="mailto:sherwin@nlm.nih.gov">Ziying Sherwin</a> provided <a
3773 href="http://xmlsoft.org/messages/0488.html">man pages</a></li>
Daniel Veillard5168dbf2001-07-07 00:18:23 +0000[diff] [blame]3774 <li>there is a module for <a
3775 href="http://acs-misc.sourceforge.net/nsxml.html">libxml/libxslt support
3776 in OpenNSD/AOLServer</a></li>
Daniel Veillard2d347fa2002-03-17 10:34:11 +0000[diff] [blame]3777 <li><a href="mailto:dkuhlman@cutter.rexx.com">Dave Kuhlman</a> provided the
3778 first version of libxml/libxslt <a
3779 href="http://www.rexx.com/~dkuhlman">wrappers for Python</a></li>
Daniel Veillard1aadc442001-11-28 13:10:32 +0000[diff] [blame]3780 <li>Petr Kozelka provides <a
3781 href="http://sourceforge.net/projects/libxml2-pas">Pascal units to glue
3782 libxml2</a> with Kylix and Delphi and other Pascal compilers</li>
Daniel Veillard2d347fa2002-03-17 10:34:11 +0000[diff] [blame]3783 <li><a href="mailto:aleksey@aleksey.com">Aleksey Sanin</a> implemented the
3784 <a href="http://www.w3.org/Signature/">XML Canonicalization and XML
3785 Digital Signature</a> <a
3786 href="http://www.aleksey.com/xmlsec/">implementations for libxml2</a></li>
Daniel Veillardc310d562000-06-23 18:32:15 +0000[diff] [blame]3787</ul>
3788
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3789<p></p>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]3790</body>
3791</html>