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blob: edc8fe1eb9c288add842702c213f21002b49666b [file] [log] [blame]
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
163 you made to libxml, but it would be graceful to provide back bug fixes and
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]164 improvements as patches for possible incorporation in the main
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
573<h3>2.4.21: Apr 29 2002</h3>
574
575<p>This release is both a bug fix release and also contains the early XML
576Schemas <a href="http://www.w3.org/TR/xmlschema-1/">structures</a> and <a
577href="http://www.w3.org/TR/xmlschema-2/">datatypes</a> code, beware, all
578interfaces are likely to change, there is huge holes, it is clearly a work in
579progress and don't even think of putting this code in a production system,
Daniel Veillarde6d8e202002-05-02 06:11:10 +0000[diff] [blame]580it's actually not compiled in by default. The real fixes are:</p>
Daniel Veillardcf27f7c2002-04-30 07:12:39 +0000[diff] [blame]581<ul>
582 <li>a couple of bugs or limitations introduced in 2.4.20</li>
583 <li>patches for Borland C++ and MSC by Igor</li>
584 <li>some fixes on XPath strings and conformance patches by Richard
585 Jinks</li>
586 <li>patch from Aleksey for the ExcC14N specification</li>
587 <li>OSF/1 bug fix by Bjorn</li>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]588</ul>
589
Daniel Veillarda7084cd2002-04-15 17:12:47 +0000[diff] [blame]590<h3>2.4.20: Apr 15 2002</h3>
591<ul>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]592 <li>bug fixes: file descriptor leak, XPath, HTML output, DTD validation</li>
Daniel Veillarda7084cd2002-04-15 17:12:47 +0000[diff] [blame]593 <li>XPath conformance testing by Richard Jinks</li>
594 <li>Portability fixes: Solaris, MPE/iX, Windows, OSF/1, python bindings,
595 libxml.m4</li>
596</ul>
597
Daniel Veillard19274092002-03-25 16:48:03 +0000[diff] [blame]598<h3>2.4.19: Mar 25 2002</h3>
599<ul>
600 <li>bug fixes: half a dozen XPath bugs, Validation, ISO-Latin to UTF8
601 encoder</li>
602 <li>portability fixes in the HTTP code</li>
Daniel Veillardb2fb8ed2002-04-01 09:33:12 +0000[diff] [blame]603 <li>memory allocation checks using valgrind, and profiling tests</li>
Daniel Veillard19274092002-03-25 16:48:03 +0000[diff] [blame]604 <li>revamp of the Windows build and Makefiles</li>
605</ul>
606
Daniel Veillard34ce8be2002-03-18 19:37:11 +0000[diff] [blame]607<h3>2.4.18: Mar 18 2002</h3>
608<ul>
609 <li>bug fixes: tree, SAX, canonicalization, validation, portability,
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]610 XPath</li>
Daniel Veillard34ce8be2002-03-18 19:37:11 +0000[diff] [blame]611 <li>removed the --with-buffer option it was becoming unmaintainable</li>
612 <li>serious cleanup of the Python makefiles</li>
613 <li>speedup patch to XPath very effective for DocBook stylesheets</li>
614 <li>Fixes for Windows build, cleanup of the documentation</li>
615</ul>
616
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]617<h3>2.4.17: Mar 8 2002</h3>
618<ul>
619 <li>a lot of bug fixes, including "namespace nodes have no parents in
620 XPath"</li>
621 <li>fixed/improved the Python wrappers, added more examples and more
622 regression tests, XPath extension functions can now return node-sets</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]623 <li>added the XML Canonicalization support from Aleksey Sanin</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]624</ul>
625
Daniel Veillard5f4b5992002-02-20 10:22:49 +0000[diff] [blame]626<h3>2.4.16: Feb 20 2002</h3>
627<ul>
628 <li>a lot of bug fixes, most of them were triggered by the XML Testsuite
629 from OASIS and W3C. Compliance has been significantly improved.</li>
630 <li>a couple of portability fixes too.</li>
631</ul>
632
Daniel Veillard397ff112002-02-11 18:27:20 +0000[diff] [blame]633<h3>2.4.15: Feb 11 2002</h3>
634<ul>
635 <li>Fixed the Makefiles, especially the python module ones</li>
636 <li>A few bug fixes and cleanup</li>
637 <li>Includes cleanup</li>
638</ul>
639
Daniel Veillardb6c1e2f2002-02-08 14:52:52 +0000[diff] [blame]640<h3>2.4.14: Feb 8 2002</h3>
641<ul>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]642 <li>Change of License to the <a
Daniel Veillardb6c1e2f2002-02-08 14:52:52 +0000[diff] [blame]643 href="http://www.opensource.org/licenses/mit-license.html">MIT
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]644 License</a> basically for integration in XFree86 codebase, and removing
645 confusion around the previous dual-licensing</li>
Daniel Veillardb6c1e2f2002-02-08 14:52:52 +0000[diff] [blame]646 <li>added Python bindings, beta software but should already be quite
647 complete</li>
648 <li>a large number of fixes and cleanups, especially for all tree
649 manipulations</li>
650 <li>cleanup of the headers, generation of a reference API definition in
651 XML</li>
652</ul>
653
654<h3>2.4.13: Jan 14 2002</h3>
Daniel Veillard744683d2002-01-14 17:30:20 +0000[diff] [blame]655<ul>
656 <li>update of the documentation: John Fleck and Charlie Bozeman</li>
657 <li>cleanup of timing code from Justin Fletcher</li>
658 <li>fixes for Windows and initial thread support on Win32: Igor and Serguei
659 Narojnyi</li>
660 <li>Cygwin patch from Robert Collins</li>
661 <li>added xmlSetEntityReferenceFunc() for Keith Isdale work on xsldbg</li>
662</ul>
663
Daniel Veillardef90ba72001-12-07 14:24:22 +0000[diff] [blame]664<h3>2.4.12: Dec 7 2001</h3>
665<ul>
666 <li>a few bug fixes: thread (Gary Pennington), xmllint (Geert Kloosterman),
667 XML parser (Robin Berjon), XPointer (Danny Jamshy), I/O cleanups
668 (robert)</li>
669 <li>Eric Lavigne contributed project files for MacOS</li>
670 <li>some makefiles cleanups</li>
671</ul>
672
Daniel Veillarda4871052001-11-26 13:19:48 +0000[diff] [blame]673<h3>2.4.11: Nov 26 2001</h3>
674<ul>
675 <li>fixed a couple of errors in the includes, fixed a few bugs, some code
676 cleanups</li>
677 <li>xmllint man pages improvement by Heiko Rupp</li>
678 <li>updated VMS build instructions from John A Fotheringham</li>
679 <li>Windows Makefiles updates from Igor</li>
680</ul>
681
Daniel Veillard43d3f612001-11-10 11:57:23 +0000[diff] [blame]682<h3>2.4.10: Nov 10 2001</h3>
683<ul>
684 <li>URI escaping fix (Joel Young)</li>
685 <li>added xmlGetNodePath() (for paths or XPointers generation)</li>
686 <li>Fixes namespace handling problems when using DTD and validation</li>
687 <li>improvements on xmllint: Morus Walter patches for --format and
688 --encode, Stefan Kost and Heiko Rupp improvements on the --shell</li>
689 <li>fixes for xmlcatalog linking pointed by Weiqi Gao</li>
690 <li>fixes to the HTML parser</li>
691</ul>
692
693<h3>2.4.9: Nov 6 2001</h3>
694<ul>
695 <li>fixes more catalog bugs</li>
696 <li>avoid a compilation problem, improve xmlGetLineNo()</li>
697</ul>
698
Daniel Veillarded421aa2001-11-04 21:22:45 +0000[diff] [blame]699<h3>2.4.8: Nov 4 2001</h3>
700<ul>
701 <li>fixed SGML catalogs broken in previous release, updated xmlcatalog
702 tool</li>
703 <li>fixed a compile errors and some includes troubles.</li>
704</ul>
705
Daniel Veillard52dcab32001-10-30 12:51:17 +0000[diff] [blame]706<h3>2.4.7: Oct 30 2001</h3>
707<ul>
708 <li>exported some debugging interfaces</li>
709 <li>serious rewrite of the catalog code</li>
710 <li>integrated Gary Pennington thread safety patch, added configure option
711 and regression tests</li>
712 <li>removed an HTML parser bug</li>
713 <li>fixed a couple of potentially serious validation bugs</li>
714 <li>integrated the SGML DocBook support in xmllint</li>
715 <li>changed the nanoftp anonymous login passwd</li>
716 <li>some I/O cleanup and a couple of interfaces for Perl wrapper</li>
717 <li>general bug fixes</li>
718 <li>updated xmllint man page by John Fleck</li>
719 <li>some VMS and Windows updates</li>
720</ul>
721
Daniel Veillard60087f32001-10-10 09:45:09 +0000[diff] [blame]722<h3>2.4.6: Oct 10 2001</h3>
723<ul>
Daniel Veillard52dcab32001-10-30 12:51:17 +0000[diff] [blame]724 <li>added an updated man pages by John Fleck</li>
Daniel Veillard60087f32001-10-10 09:45:09 +0000[diff] [blame]725 <li>portability and configure fixes</li>
726 <li>an infinite loop on the HTML parser was removed (William)</li>
727 <li>Windows makefile patches from Igor</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]728 <li>fixed half a dozen bugs reported for libxml or libxslt</li>
Daniel Veillard60087f32001-10-10 09:45:09 +0000[diff] [blame]729 <li>updated xmlcatalog to be able to modify SGML super catalogs</li>
730</ul>
731
Daniel Veillarddadd0872001-09-15 09:21:44 +0000[diff] [blame]732<h3>2.4.5: Sep 14 2001</h3>
733<ul>
734 <li>Remove a few annoying bugs in 2.4.4</li>
735 <li>forces the HTML serializer to output decimal charrefs since some
736 version of Netscape can't handle hexadecimal ones</li>
737</ul>
738
739<h3>1.8.16: Sep 14 2001</h3>
740<ul>
741 <li>maintenance release of the old libxml1 branch, couple of bug and
742 portability fixes</li>
743</ul>
744
Daniel Veillard04382ae2001-09-12 18:51:30 +0000[diff] [blame]745<h3>2.4.4: Sep 12 2001</h3>
746<ul>
747 <li>added --convert to xmlcatalog, bug fixes and cleanups of XML
748 Catalog</li>
749 <li>a few bug fixes and some portability changes</li>
750 <li>some documentation cleanups</li>
751</ul>
752
Daniel Veillard39936902001-08-24 00:49:01 +0000[diff] [blame]753<h3>2.4.3: Aug 23 2001</h3>
754<ul>
755 <li>XML Catalog support see the doc</li>
756 <li>New NaN/Infinity floating point code</li>
757 <li>A few bug fixes</li>
758</ul>
759
760<h3>2.4.2: Aug 15 2001</h3>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]761<ul>
762 <li>adds xmlLineNumbersDefault() to control line number generation</li>
763 <li>lot of bug fixes</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]764 <li>the Microsoft MSC projects files should now be up to date</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]765 <li>inheritance of namespaces from DTD defaulted attributes</li>
766 <li>fixes a serious potential security bug</li>
767 <li>added a --format option to xmllint</li>
768</ul>
769
770<h3>2.4.1: July 24 2001</h3>
771<ul>
772 <li>possibility to keep line numbers in the tree</li>
773 <li>some computation NaN fixes</li>
774 <li>extension of the XPath API</li>
775 <li>cleanup for alpha and ia64 targets</li>
776 <li>patch to allow saving through HTTP PUT or POST</li>
Daniel Veillard09ab7e12001-07-10 15:49:44 +0000[diff] [blame]777</ul>
778
779<h3>2.4.0: July 10 2001</h3>
780<ul>
781 <li>Fixed a few bugs in XPath, validation, and tree handling.</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]782 <li>Fixed XML Base implementation, added a couple of examples to the
Daniel Veillard09ab7e12001-07-10 15:49:44 +0000[diff] [blame]783 regression tests</li>
784 <li>A bit of cleanup</li>
Daniel Veillardab8500d2000-10-15 21:06:19 +0000[diff] [blame]785</ul>
786
Daniel Veillard5b43fde2001-07-05 23:31:40 +0000[diff] [blame]787<h3>2.3.14: July 5 2001</h3>
788<ul>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]789 <li>fixed some entities problems and reduce memory requirement when
790 substituting them</li>
Daniel Veillard5b43fde2001-07-05 23:31:40 +0000[diff] [blame]791 <li>lots of improvements in the XPath queries interpreter can be
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]792 substantially faster</li>
Daniel Veillard5b43fde2001-07-05 23:31:40 +0000[diff] [blame]793 <li>Makefiles and configure cleanups</li>
794 <li>Fixes to XPath variable eval, and compare on empty node set</li>
795 <li>HTML tag closing bug fixed</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]796 <li>Fixed an URI reference computation problem when validating</li>
Daniel Veillard5b43fde2001-07-05 23:31:40 +0000[diff] [blame]797</ul>
798
Daniel Veillard2adbb512001-06-28 16:20:36 +0000[diff] [blame]799<h3>2.3.13: June 28 2001</h3>
800<ul>
801 <li>2.3.12 configure.in was broken as well as the push mode XML parser</li>
802 <li>a few more fixes for compilation on Windows MSC by Yon Derek</li>
803</ul>
804
805<h3>1.8.14: June 28 2001</h3>
806<ul>
807 <li>Zbigniew Chyla gave a patch to use the old XML parser in push mode</li>
808 <li>Small Makefile fix</li>
809</ul>
810
Daniel Veillard11648102001-06-26 16:08:24 +0000[diff] [blame]811<h3>2.3.12: June 26 2001</h3>
812<ul>
813 <li>lots of cleanup</li>
814 <li>a couple of validation fix</li>
815 <li>fixed line number counting</li>
816 <li>fixed serious problems in the XInclude processing</li>
817 <li>added support for UTF8 BOM at beginning of entities</li>
818 <li>fixed a strange gcc optimizer bugs in xpath handling of float, gcc-3.0
819 miscompile uri.c (William), Thomas Leitner provided a fix for the
820 optimizer on Tru64</li>
821 <li>incorporated Yon Derek and Igor Zlatkovic fixes and improvements for
822 compilation on Windows MSC</li>
823 <li>update of libxml-doc.el (Felix Natter)</li>
824 <li>fixed 2 bugs in URI normalization code</li>
825</ul>
826
Daniel Veillarde3c81b52001-06-17 14:50:34 +0000[diff] [blame]827<h3>2.3.11: June 17 2001</h3>
828<ul>
829 <li>updates to trio, Makefiles and configure should fix some portability
830 problems (alpha)</li>
831 <li>fixed some HTML serialization problems (pre, script, and block/inline
832 handling), added encoding aware APIs, cleanup of this code</li>
833 <li>added xmlHasNsProp()</li>
834 <li>implemented a specific PI for encoding support in the DocBook SGML
835 parser</li>
836 <li>some XPath fixes (-Infinity, / as a function parameter and namespaces
837 node selection)</li>
838 <li>fixed a performance problem and an error in the validation code</li>
839 <li>fixed XInclude routine to implement the recursive behaviour</li>
840 <li>fixed xmlFreeNode problem when libxml is included statically twice</li>
841 <li>added --version to xmllint for bug reports</li>
842</ul>
843
Daniel Veillard2e4f1882001-06-01 10:11:57 +0000[diff] [blame]844<h3>2.3.10: June 1 2001</h3>
845<ul>
846 <li>fixed the SGML catalog support</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]847 <li>a number of reported bugs got fixed, in XPath, iconv detection,
848 XInclude processing</li>
Daniel Veillard2e4f1882001-06-01 10:11:57 +0000[diff] [blame]849 <li>XPath string function should now handle unicode correctly</li>
850</ul>
851
Daniel Veillard4623acd2001-05-19 15:13:15 +0000[diff] [blame]852<h3>2.3.9: May 19 2001</h3>
853
854<p>Lots of bugfixes, and added a basic SGML catalog support:</p>
855<ul>
856 <li>HTML push bugfix #54891 and another patch from Jonas Borgström</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]857 <li>some serious speed optimization again</li>
Daniel Veillard4623acd2001-05-19 15:13:15 +0000[diff] [blame]858 <li>some documentation cleanups</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]859 <li>trying to get better linking on Solaris (-R)</li>
Daniel Veillard4623acd2001-05-19 15:13:15 +0000[diff] [blame]860 <li>XPath API cleanup from Thomas Broyer</li>
861 <li>Validation bug fixed #54631, added a patch from Gary Pennington, fixed
862 xmlValidGetValidElements()</li>
863 <li>Added an INSTALL file</li>
864 <li>Attribute removal added to API: #54433</li>
865 <li>added a basic support for SGML catalogs</li>
866 <li>fixed xmlKeepBlanksDefault(0) API</li>
867 <li>bugfix in xmlNodeGetLang()</li>
868 <li>fixed a small configure portability problem</li>
869 <li>fixed an inversion of SYSTEM and PUBLIC identifier in HTML document</li>
870</ul>
871
Daniel Veillarda265af72001-05-14 11:13:58 +0000[diff] [blame]872<h3>1.8.13: May 14 2001</h3>
873<ul>
874 <li>bugfixes release of the old libxml1 branch used by Gnome</li>
875</ul>
876
Daniel Veillard3bbbe6f2001-05-03 11:15:37 +0000[diff] [blame]877<h3>2.3.8: May 3 2001</h3>
878<ul>
879 <li>Integrated an SGML DocBook parser for the Gnome project</li>
880 <li>Fixed a few things in the HTML parser</li>
881 <li>Fixed some XPath bugs raised by XSLT use, tried to fix the floating
882 point portability issue</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]883 <li>Speed improvement (8M/s for SAX, 3M/s for DOM, 1.5M/s for
884 DOM+validation using the XML REC as input and a 700MHz celeron).</li>
Daniel Veillard3bbbe6f2001-05-03 11:15:37 +0000[diff] [blame]885 <li>incorporated more Windows cleanup</li>
886 <li>added xmlSaveFormatFile()</li>
887 <li>fixed problems in copying nodes with entities references (gdome)</li>
888 <li>removed some troubles surrounding the new validation module</li>
889</ul>
890
Daniel Veillarda41123c2001-04-22 19:31:20 +0000[diff] [blame]891<h3>2.3.7: April 22 2001</h3>
892<ul>
893 <li>lots of small bug fixes, corrected XPointer</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]894 <li>Non deterministic content model validation support</li>
Daniel Veillarda41123c2001-04-22 19:31:20 +0000[diff] [blame]895 <li>added xmlDocCopyNode for gdome2</li>
896 <li>revamped the way the HTML parser handles end of tags</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]897 <li>XPath: corrections of namespaces support and number formatting</li>
Daniel Veillarda41123c2001-04-22 19:31:20 +0000[diff] [blame]898 <li>Windows: Igor Zlatkovic patches for MSC compilation</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]899 <li>HTML output fixes from P C Chow and William M. Brack</li>
Daniel Veillarda41123c2001-04-22 19:31:20 +0000[diff] [blame]900 <li>Improved validation speed sensible for DocBook</li>
901 <li>fixed a big bug with ID declared in external parsed entities</li>
902 <li>portability fixes, update of Trio from Bjorn Reese</li>
903</ul>
904
Daniel Veillardafc73112001-04-11 11:51:41 +0000[diff] [blame]905<h3>2.3.6: April 8 2001</h3>
906<ul>
907 <li>Code cleanup using extreme gcc compiler warning options, found and
908 cleared half a dozen potential problem</li>
909 <li>the Eazel team found an XML parser bug</li>
910 <li>cleaned up the user of some of the string formatting function. used the
911 trio library code to provide the one needed when the platform is missing
912 them</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]913 <li>xpath: removed a memory leak and fixed the predicate evaluation
914 problem, extended the testsuite and cleaned up the result. XPointer seems
915 broken ...</li>
Daniel Veillardafc73112001-04-11 11:51:41 +0000[diff] [blame]916</ul>
917
Daniel Veillard56a4cb82001-03-24 17:00:36 +0000[diff] [blame]918<h3>2.3.5: Mar 23 2001</h3>
919<ul>
920 <li>Biggest change is separate parsing and evaluation of XPath expressions,
921 there is some new APIs for this too</li>
922 <li>included a number of bug fixes(XML push parser, 51876, notations,
923 52299)</li>
924 <li>Fixed some portability issues</li>
925</ul>
926
Daniel Veillarde356c282001-03-10 12:32:04 +0000[diff] [blame]927<h3>2.3.4: Mar 10 2001</h3>
928<ul>
929 <li>Fixed bugs #51860 and #51861</li>
930 <li>Added a global variable xmlDefaultBufferSize to allow default buffer
931 size to be application tunable.</li>
932 <li>Some cleanup in the validation code, still a bug left and this part
933 should probably be rewritten to support ambiguous content model :-\</li>
934 <li>Fix a couple of serious bugs introduced or raised by changes in 2.3.3
935 parser</li>
936 <li>Fixed another bug in xmlNodeGetContent()</li>
937 <li>Bjorn fixed XPath node collection and Number formatting</li>
938 <li>Fixed a loop reported in the HTML parsing</li>
939 <li>blank space are reported even if the Dtd content model proves that they
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]940 are formatting spaces, this is for XML conformance</li>
Daniel Veillarde356c282001-03-10 12:32:04 +0000[diff] [blame]941</ul>
942
Daniel Veillardb402c072001-03-01 17:28:58 +0000[diff] [blame]943<h3>2.3.3: Mar 1 2001</h3>
944<ul>
945 <li>small change in XPath for XSLT</li>
946 <li>documentation cleanups</li>
947 <li>fix in validation by Gary Pennington</li>
948 <li>serious parsing performances improvements</li>
949</ul>
950
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]951<h3>2.3.2: Feb 24 2001</h3>
Daniel Veillard71681102001-02-24 17:48:53 +0000[diff] [blame]952<ul>
953 <li>chasing XPath bugs, found a bunch, completed some TODO</li>
954 <li>fixed a Dtd parsing bug</li>
955 <li>fixed a bug in xmlNodeGetContent</li>
956 <li>ID/IDREF support partly rewritten by Gary Pennington</li>
957</ul>
958
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]959<h3>2.3.1: Feb 15 2001</h3>
Daniel Veillard6e6a6cc2001-02-15 15:55:44 +0000[diff] [blame]960<ul>
961 <li>some XPath and HTML bug fixes for XSLT</li>
962 <li>small extension of the hash table interfaces for DOM gdome2
963 implementation</li>
964 <li>A few bug fixes</li>
965</ul>
966
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]967<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]968<ul>
969 <li>Lots of XPath bug fixes</li>
970 <li>Add a mode with Dtd lookup but without validation error reporting for
971 XSLT</li>
972 <li>Add support for text node without escaping (XSLT)</li>
973 <li>bug fixes for xmlCheckFilename</li>
974 <li>validation code bug fixes from Gary Pennington</li>
975 <li>Patch from Paul D. Smith correcting URI path normalization</li>
976 <li>Patch to allow simultaneous install of libxml-devel and
977 libxml2-devel</li>
978 <li>the example Makefile is now fixed</li>
979 <li>added HTML to the RPM packages</li>
980 <li>tree copying bugfixes</li>
981 <li>updates to Windows makefiles</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]982 <li>optimization patch from Bjorn Reese</li>
Daniel Veillard6e6a6cc2001-02-15 15:55:44 +0000[diff] [blame]983</ul>
984
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]985<h3>2.2.11: Jan 4 2001</h3>
Daniel Veillard503b8932001-01-05 06:36:31 +0000[diff] [blame]986<ul>
987 <li>bunch of bug fixes (memory I/O, xpath, ftp/http, ...)</li>
988 <li>added htmlHandleOmittedElem()</li>
989 <li>Applied Bjorn Reese's IPV6 first patch</li>
990 <li>Applied Paul D. Smith patches for validation of XInclude results</li>
Daniel Veillard82687162001-01-22 15:32:01 +0000[diff] [blame]991 <li>added XPointer xmlns() new scheme support</li>
Daniel Veillard503b8932001-01-05 06:36:31 +0000[diff] [blame]992</ul>
993
Daniel Veillard2ddd23d2000-11-25 10:42:19 +0000[diff] [blame]994<h3>2.2.10: Nov 25 2000</h3>
Daniel Veillard9d343c42000-11-25 10:12:43 +0000[diff] [blame]995<ul>
996 <li>Fix the Windows problems of 2.2.8</li>
997 <li>integrate OpenVMS patches</li>
998 <li>better handling of some nasty HTML input</li>
999 <li>Improved the XPointer implementation</li>
1000 <li>integrate a number of provided patches</li>
1001</ul>
1002
Daniel Veillard2ddd23d2000-11-25 10:42:19 +0000[diff] [blame]1003<h3>2.2.9: Nov 25 2000</h3>
1004<ul>
1005 <li>erroneous release :-(</li>
1006</ul>
1007
Daniel Veillard28929b22000-11-13 18:22:49 +0000[diff] [blame]1008<h3>2.2.8: Nov 13 2000</h3>
1009<ul>
1010 <li>First version of <a href="http://www.w3.org/TR/xinclude">XInclude</a>
1011 support</li>
1012 <li>Patch in conditional section handling</li>
1013 <li>updated MS compiler project</li>
1014 <li>fixed some XPath problems</li>
1015 <li>added an URI escaping function</li>
1016 <li>some other bug fixes</li>
1017</ul>
1018
1019<h3>2.2.7: Oct 31 2000</h3>
1020<ul>
1021 <li>added message redirection</li>
1022 <li>XPath improvements (thanks TOM !)</li>
1023 <li>xmlIOParseDTD() added</li>
1024 <li>various small fixes in the HTML, URI, HTTP and XPointer support</li>
1025 <li>some cleanup of the Makefile, autoconf and the distribution content</li>
1026</ul>
1027
Daniel Veillard29a11cc2000-10-25 13:32:39 +0000[diff] [blame]1028<h3>2.2.6: Oct 25 2000:</h3>
1029<ul>
1030 <li>Added an hash table module, migrated a number of internal structure to
1031 those</li>
1032 <li>Fixed a posteriori validation problems</li>
1033 <li>HTTP module cleanups</li>
1034 <li>HTML parser improvements (tag errors, script/style handling, attribute
1035 normalization)</li>
1036 <li>coalescing of adjacent text nodes</li>
1037 <li>couple of XPath bug fixes, exported the internal API</li>
1038</ul>
1039
Daniel Veillardab8500d2000-10-15 21:06:19 +0000[diff] [blame]1040<h3>2.2.5: Oct 15 2000:</h3>
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000[diff] [blame]1041<ul>
Daniel Veillard189446d2000-10-13 10:23:06 +0000[diff] [blame]1042 <li>XPointer implementation and testsuite</li>
1043 <li>Lot of XPath fixes, added variable and functions registration, more
1044 tests</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]1045 <li>Portability fixes, lots of enhancements toward an easy Windows build
1046 and release</li>
Daniel Veillard189446d2000-10-13 10:23:06 +0000[diff] [blame]1047 <li>Late validation fixes</li>
1048 <li>Integrated a lot of contributed patches</li>
1049 <li>added memory management docs</li>
Daniel Veillardab8500d2000-10-15 21:06:19 +0000[diff] [blame]1050 <li>a performance problem when using large buffer seems fixed</li>
Daniel Veillard189446d2000-10-13 10:23:06 +0000[diff] [blame]1051</ul>
1052
1053<h3>2.2.4: Oct 1 2000:</h3>
1054<ul>
1055 <li>main XPath problem fixed</li>
1056 <li>Integrated portability patches for Windows</li>
1057 <li>Serious bug fixes on the URI and HTML code</li>
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]1058</ul>
1059
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]1060<h3>2.2.3: Sep 17 2000</h3>
1061<ul>
1062 <li>bug fixes</li>
1063 <li>cleanup of entity handling code</li>
1064 <li>overall review of all loops in the parsers, all sprintf usage has been
1065 checked too</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]1066 <li>Far better handling of larges Dtd. Validating against DocBook XML Dtd
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]1067 works smoothly now.</li>
1068</ul>
1069
1070<h3>1.8.10: Sep 6 2000</h3>
1071<ul>
1072 <li>bug fix release for some Gnome projects</li>
1073</ul>
1074
1075<h3>2.2.2: August 12 2000</h3>
Daniel Veillard786d7c82000-08-12 23:38:57 +0000[diff] [blame]1076<ul>
1077 <li>mostly bug fixes</li>
Daniel Veillardec78c0f2000-08-25 10:25:23 +0000[diff] [blame]1078 <li>started adding routines to access xml parser context options</li>
Daniel Veillard786d7c82000-08-12 23:38:57 +0000[diff] [blame]1079</ul>
1080
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]1081<h3>2.2.1: July 21 2000</h3>
Daniel Veillarda2679fa2000-07-22 02:38:15 +0000[diff] [blame]1082<ul>
1083 <li>a purely bug fixes release</li>
1084 <li>fixed an encoding support problem when parsing from a memory block</li>
1085 <li>fixed a DOCTYPE parsing problem</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]1086 <li>removed a bug in the function allowing to override the memory
1087 allocation routines</li>
Daniel Veillarda2679fa2000-07-22 02:38:15 +0000[diff] [blame]1088</ul>
1089
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]1090<h3>2.2.0: July 14 2000</h3>
Daniel Veillard94e90602000-07-17 14:38:19 +0000[diff] [blame]1091<ul>
1092 <li>applied a lot of portability fixes</li>
1093 <li>better encoding support/cleanup and saving (content is now always
1094 encoded in UTF-8)</li>
1095 <li>the HTML parser now correctly handles encodings</li>
1096 <li>added xmlHasProp()</li>
1097 <li>fixed a serious problem with &amp;#38;</li>
1098 <li>propagated the fix to FTP client</li>
1099 <li>cleanup, bugfixes, etc ...</li>
1100 <li>Added a page about <a href="encoding.html">libxml Internationalization
1101 support</a></li>
1102</ul>
1103
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1104<h3>1.8.9: July 9 2000</h3>
1105<ul>
1106 <li>fixed the spec the RPMs should be better</li>
1107 <li>fixed a serious bug in the FTP implementation, released 1.8.9 to solve
1108 rpmfind users problem</li>
1109</ul>
1110
Daniel Veillard6388e172000-07-03 16:07:19 +0000[diff] [blame]1111<h3>2.1.1: July 1 2000</h3>
1112<ul>
1113 <li>fixes a couple of bugs in the 2.1.0 packaging</li>
1114 <li>improvements on the HTML parser</li>
1115</ul>
1116
Daniel Veillard3f6f7f62000-06-30 17:58:25 +0000[diff] [blame]1117<h3>2.1.0 and 1.8.8: June 29 2000</h3>
1118<ul>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]1119 <li>1.8.8 is mostly a commodity package for upgrading to libxml2 according to
Daniel Veillard3f6f7f62000-06-30 17:58:25 +0000[diff] [blame]1120 <a href="upgrade.html">new instructions</a>. It fixes a nasty problem
1121 about &amp;#38; charref parsing</li>
1122 <li>2.1.0 also ease the upgrade from libxml v1 to the recent version. it
1123 also contains numerous fixes and enhancements:
1124 <ul>
1125 <li>added xmlStopParser() to stop parsing</li>
1126 <li>improved a lot parsing speed when there is large CDATA blocs</li>
1127 <li>includes XPath patches provided by Picdar Technology</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]1128 <li>tried to fix as much as possible DTD validation and namespace
Daniel Veillard3f6f7f62000-06-30 17:58:25 +0000[diff] [blame]1129 related problems</li>
1130 <li>output to a given encoding has been added/tested</li>
1131 <li>lot of various fixes</li>
1132 </ul>
1133 </li>
1134</ul>
1135
Daniel Veillarde0aed302000-04-16 08:52:20 +0000[diff] [blame]1136<h3>2.0.0: Apr 12 2000</h3>
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]1137<ul>
1138 <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^]1139 idea to check the 1.x to 2.x upgrade instructions. NOTE: while initially
1140 scheduled for Apr 3 the release occurred only on Apr 12 due to massive
Daniel Veillarde0aed302000-04-16 08:52:20 +0000[diff] [blame]1141 workload.</li>
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]1142 <li>The include are now located under $prefix/include/libxml (instead of
Daniel Veillarde0aed302000-04-16 08:52:20 +0000[diff] [blame]1143 $prefix/include/gnome-xml), they also are referenced by
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1144 <pre>#include &lt;libxml/xxx.h&gt;</pre>
Daniel Veillarde0aed302000-04-16 08:52:20 +0000[diff] [blame]1145 <p>instead of</p>
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]1146 <pre>#include "xxx.h"</pre>
1147 </li>
Daniel Veillard8f621982000-03-20 13:07:15 +0000[diff] [blame]1148 <li>a new URI module for parsing URIs and following strictly RFC 2396</li>
1149 <li>the memory allocation routines used by libxml can now be overloaded
1150 dynamically by using xmlMemSetup()</li>
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]1151 <li>The previously CVS only tool tester has been renamed
1152 <strong>xmllint</strong> and is now installed as part of the libxml2
1153 package</li>
Daniel Veillarde0aed302000-04-16 08:52:20 +0000[diff] [blame]1154 <li>The I/O interface has been revamped. There is now ways to plug in
1155 specific I/O modules, either at the URI scheme detection level using
1156 xmlRegisterInputCallbacks() or by passing I/O functions when creating a
1157 parser context using xmlCreateIOParserCtxt()</li>
1158 <li>there is a C preprocessor macro LIBXML_VERSION providing the version
1159 number of the libxml module in use</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]1160 <li>a number of optional features of libxml can now be excluded at
1161 configure time (FTP/HTTP/HTML/XPath/Debug)</li>
Daniel Veillardedfb29b2000-03-14 19:59:05 +0000[diff] [blame]1162</ul>
1163
1164<h3>2.0.0beta: Mar 14 2000</h3>
1165<ul>
1166 <li>This is a first Beta release of libxml version 2</li>
Daniel Veillarde356c282001-03-10 12:32:04 +0000[diff] [blame]1167 <li>It's available only from<a href="ftp://xmlsoft.org/">xmlsoft.org
1168 FTP</a>, it's packaged as libxml2-2.0.0beta and available as tar and
1169 RPMs</li>
Daniel Veillardedfb29b2000-03-14 19:59:05 +0000[diff] [blame]1170 <li>This version is now the head in the Gnome CVS base, the old one is
1171 available under the tag LIB_XML_1_X</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]1172 <li>This includes a very large set of changes. From a programmatic point of
Daniel Veillardedfb29b2000-03-14 19:59:05 +0000[diff] [blame]1173 view applications should not have to be modified too much, check the <a
1174 href="upgrade.html">upgrade page</a></li>
1175 <li>Some interfaces may changes (especially a bit about encoding).</li>
1176 <li>the updates includes:
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]1177 <ul>
Daniel Veillardedfb29b2000-03-14 19:59:05 +0000[diff] [blame]1178 <li>fix I18N support. ISO-Latin-x/UTF-8/UTF-16 (nearly) seems correctly
1179 handled now</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]1180 <li>Better handling of entities, especially well-formedness checking
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]1181 and proper PEref extensions in external subsets</li>
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]1182 <li>DTD conditional sections</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]1183 <li>Validation now correctly handle entities content</li>
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]1184 <li><a href="http://rpmfind.net/tools/gdome/messages/0039.html">change
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]1185 structures to accommodate DOM</a></li>
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]1186 </ul>
1187 </li>
Daniel Veillardedfb29b2000-03-14 19:59:05 +0000[diff] [blame]1188 <li>Serious progress were made toward compliance, <a
1189 href="conf/result.html">here are the result of the test</a> against the
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]1190 OASIS testsuite (except the Japanese tests since I don't support that
Daniel Veillardedfb29b2000-03-14 19:59:05 +0000[diff] [blame]1191 encoding yet). This URL is rebuilt every couple of hours using the CVS
1192 head version.</li>
Daniel Veillarde41f2b72000-01-30 20:00:07 +0000[diff] [blame]1193</ul>
1194
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1195<h3>1.8.7: Mar 6 2000</h3>
1196<ul>
1197 <li>This is a bug fix release:</li>
1198 <li>It is possible to disable the ignorable blanks heuristic used by
1199 libxml-1.x, a new function xmlKeepBlanksDefault(0) will allow this. Note
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]1200 that for adherence to XML spec, this behaviour will be disabled by
1201 default in 2.x . The same function will allow to keep compatibility for
1202 old code.</li>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1203 <li>Blanks in &lt;a&gt; &lt;/a&gt; constructs are not ignored anymore,
1204 avoiding heuristic is really the Right Way :-\</li>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1205 <li>The unchecked use of snprintf which was breaking libxml-1.8.6
1206 compilation on some platforms has been fixed</li>
1207 <li>nanoftp.c nanohttp.c: Fixed '#' and '?' stripping when processing
1208 URIs</li>
1209</ul>
1210
Daniel Veillarde41f2b72000-01-30 20:00:07 +0000[diff] [blame]1211<h3>1.8.6: Jan 31 2000</h3>
1212<ul>
1213 <li>added a nanoFTP transport module, debugged until the new version of <a
1214 href="http://rpmfind.net/linux/rpm2html/rpmfind.html">rpmfind</a> can use
1215 it without troubles</li>
Daniel Veillardda07c342000-01-25 18:31:22 +0000[diff] [blame]1216</ul>
1217
1218<h3>1.8.5: Jan 21 2000</h3>
1219<ul>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]1220 <li>adding APIs to parse a well balanced chunk of XML (production <a
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]1221 href="http://www.w3.org/TR/REC-xml#NT-content">[43] content</a> of the
1222 XML spec)</li>
Daniel Veillard461a66c2000-01-18 18:01:01 +0000[diff] [blame]1223 <li>fixed a hideous bug in xmlGetProp pointed by Rune.Djurhuus@fast.no</li>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1224 <li>Jody Goldberg &lt;jgoldberg@home.com&gt; provided another patch trying
1225 to solve the zlib checks problems</li>
Daniel Veillard461a66c2000-01-18 18:01:01 +0000[diff] [blame]1226 <li>The current state in gnome CVS base is expected to ship as 1.8.5 with
1227 gnumeric soon</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]1228</ul>
1229
1230<h3>1.8.4: Jan 13 2000</h3>
1231<ul>
1232 <li>bug fixes, reintroduced xmlNewGlobalNs(), fixed xmlNewNs()</li>
1233 <li>all exit() call should have been removed from libxml</li>
1234 <li>fixed a problem with INCLUDE_WINSOCK on WIN32 platform</li>
1235 <li>added newDocFragment()</li>
Daniel Veillardf84f71f2000-01-05 19:54:23 +0000[diff] [blame]1236</ul>
1237
1238<h3>1.8.3: Jan 5 2000</h3>
1239<ul>
1240 <li>a Push interface for the XML and HTML parsers</li>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1241 <li>a shell-like interface to the document tree (try tester --shell :-)</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]1242 <li>lots of bug fixes and improvement added over XMas holidays</li>
Daniel Veillard437b87b2000-01-03 17:30:46 +0000[diff] [blame]1243 <li>fixed the DTD parsing code to work with the xhtml DTD</li>
Daniel Veillardf84f71f2000-01-05 19:54:23 +0000[diff] [blame]1244 <li>added xmlRemoveProp(), xmlRemoveID() and xmlRemoveRef()</li>
1245 <li>Fixed bugs in xmlNewNs()</li>
Daniel Veillard437b87b2000-01-03 17:30:46 +0000[diff] [blame]1246 <li>External entity loading code has been revamped, now it uses
Daniel Veillardf84f71f2000-01-05 19:54:23 +0000[diff] [blame]1247 xmlLoadExternalEntity(), some fix on entities processing were added</li>
Daniel Veillard437b87b2000-01-03 17:30:46 +0000[diff] [blame]1248 <li>cleaned up WIN32 includes of socket stuff</li>
Daniel Veillard5cb5ab81999-12-21 15:35:29 +0000[diff] [blame]1249</ul>
1250
1251<h3>1.8.2: Dec 21 1999</h3>
1252<ul>
Daniel Veillardb24054a1999-12-18 15:32:46 +0000[diff] [blame]1253 <li>I got another problem with includes and C++, I hope this issue is fixed
1254 for good this time</li>
Daniel Veillard5cb5ab81999-12-21 15:35:29 +0000[diff] [blame]1255 <li>Added a few tree modification functions: xmlReplaceNode,
1256 xmlAddPrevSibling, xmlAddNextSibling, xmlNodeSetName and
1257 xmlDocSetRootElement</li>
1258 <li>Tried to improve the HTML output with help from <a
1259 href="mailto:clahey@umich.edu">Chris Lahey</a></li>
Daniel Veillarde4e51311999-12-18 15:32:46 +0000[diff] [blame]1260</ul>
Daniel Veillardb24054a1999-12-18 15:32:46 +0000[diff] [blame]1261
Daniel Veillarde4e51311999-12-18 15:32:46 +0000[diff] [blame]1262<h3>1.8.1: Dec 18 1999</h3>
1263<ul>
1264 <li>various patches to avoid troubles when using libxml with C++ compilers
1265 the "namespace" keyword and C escaping in include files</li>
1266 <li>a problem in one of the core macros IS_CHAR was corrected</li>
1267 <li>fixed a bug introduced in 1.8.0 breaking default namespace processing,
1268 and more specifically the Dia application</li>
Daniel Veillard944b5ff1999-12-15 19:08:24 +0000[diff] [blame]1269 <li>fixed a posteriori validation (validation after parsing, or by using a
1270 Dtd not specified in the original document)</li>
Daniel Veillardb24054a1999-12-18 15:32:46 +0000[diff] [blame]1271 <li>fixed a bug in</li>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]1272</ul>
1273
1274<h3>1.8.0: Dec 12 1999</h3>
1275<ul>
1276 <li>cleanup, especially memory wise</li>
1277 <li>the parser should be more reliable, especially the HTML one, it should
1278 not crash, whatever the input !</li>
1279 <li>Integrated various patches, especially a speedup improvement for large
1280 dataset from <a href="mailto:cnygard@bellatlantic.net">Carl Nygard</a>,
1281 configure with --with-buffers to enable them.</li>
1282 <li>attribute normalization, oops should have been added long ago !</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]1283 <li>attributes defaulted from DTDs should be available, xmlSetProp() now
1284 does entities escaping by default.</li>
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000[diff] [blame]1285</ul>
Daniel Veillard35008381999-10-25 13:15:52 +0000[diff] [blame]1286
1287<h3>1.7.4: Oct 25 1999</h3>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]1288<ul>
Daniel Veillard35008381999-10-25 13:15:52 +0000[diff] [blame]1289 <li>Lots of HTML improvement</li>
1290 <li>Fixed some errors when saving both XML and HTML</li>
1291 <li>More examples, the regression tests should now look clean</li>
1292 <li>Fixed a bug with contiguous charref</li>
1293</ul>
1294
1295<h3>1.7.3: Sep 29 1999</h3>
1296<ul>
1297 <li>portability problems fixed</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]1298 <li>snprintf was used unconditionally, leading to link problems on system
Daniel Veillard35008381999-10-25 13:15:52 +0000[diff] [blame]1299 were it's not available, fixed</li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]1300</ul>
1301
1302<h3>1.7.1: Sep 24 1999</h3>
1303<ul>
1304 <li>The basic type for strings manipulated by libxml has been renamed in
1305 1.7.1 from <strong>CHAR</strong> to <strong>xmlChar</strong>. The reason
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]1306 is that CHAR was conflicting with a predefined type on Windows. However
1307 on non WIN32 environment, compatibility is provided by the way of a
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]1308 <strong>#define </strong>.</li>
1309 <li>Changed another error : the use of a structure field called errno, and
1310 leading to troubles on platforms where it's a macro</li>
1311</ul>
1312
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]1313<h3>1.7.0: Sep 23 1999</h3>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]1314<ul>
1315 <li>Added the ability to fetch remote DTD or parsed entities, see the <a
Daniel Veillard9cb5ff42001-01-29 08:22:21 +0000[diff] [blame]1316 href="html/libxml-nanohttp.html">nanohttp</a> module.</li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]1317 <li>Added an errno to report errors by another mean than a simple printf
1318 like callback</li>
1319 <li>Finished ID/IDREF support and checking when validation</li>
1320 <li>Serious memory leaks fixed (there is now a <a
Daniel Veillard9cb5ff42001-01-29 08:22:21 +0000[diff] [blame]1321 href="html/libxml-xmlmemory.html">memory wrapper</a> module)</li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]1322 <li>Improvement of <a href="http://www.w3.org/TR/xpath">XPath</a>
1323 implementation</li>
1324 <li>Added an HTML parser front-end</li>
1325</ul>
1326
1327<h2><a name="XML">XML</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1328
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]1329<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]1330markup-based structured documents. Here is <a name="example">an example XML
1331document</a>:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1332<pre>&lt;?xml version="1.0"?&gt;
1333&lt;EXAMPLE prop1="gnome is great" prop2="&amp;amp; linux too"&gt;
1334 &lt;head&gt;
1335 &lt;title&gt;Welcome to Gnome&lt;/title&gt;
1336 &lt;/head&gt;
1337 &lt;chapter&gt;
1338 &lt;title&gt;The Linux adventure&lt;/title&gt;
1339 &lt;p&gt;bla bla bla ...&lt;/p&gt;
1340 &lt;image href="linus.gif"/&gt;
1341 &lt;p&gt;...&lt;/p&gt;
1342 &lt;/chapter&gt;
1343&lt;/EXAMPLE&gt;</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1344
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]1345<p>The first line specifies that it's an XML document and gives useful
1346information about its encoding. Then the document is a text format whose
1347structure is specified by tags between brackets. <strong>Each tag opened has
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1348to be closed</strong>. XML is pedantic about this. However, if a tag is empty
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]1349(no content), a single tag can serve as both the opening and closing tag if
1350it ends with <code>/&gt;</code> rather than with <code>&gt;</code>. Note
1351that, for example, the image tag has no content (just an attribute) and is
1352closed by ending the tag with <code>/&gt;</code>.</p>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]1353
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]1354<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]1355structured document maintenance (where it follows the steps of SGML) to
1356simple data encoding mechanisms like configuration file formatting (glade),
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1357spreadsheets (gnumeric), or even shorter lived documents such as WebDAV where
1358it is used to encode remote calls between a client and a server.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1359
Daniel Veillard82687162001-01-22 15:32:01 +0000[diff] [blame]1360<h2><a name="XSLT">XSLT</a></h2>
1361
Daniel Veillard6e6a6cc2001-02-15 15:55:44 +0000[diff] [blame]1362<p>Check <a href="http://xmlsoft.org/XSLT">the separate libxslt page</a></p>
1363
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]1364<p><a href="http://www.w3.org/TR/xslt">XSL Transformations</a>, is a
1365language for transforming XML documents into other XML documents (or
1366HTML/textual output).</p>
Daniel Veillard82687162001-01-22 15:32:01 +0000[diff] [blame]1367
1368<p>A separate library called libxslt is being built on top of libxml2. This
1369module "libxslt" can be found in the Gnome CVS base too.</p>
1370
Daniel Veillard383b1472001-01-23 11:39:52 +0000[diff] [blame]1371<p>You can check the <a
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]1372href="http://cvs.gnome.org/lxr/source/libxslt/FEATURES">features</a>
1373supported and the progresses on the <a
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1374href="http://cvs.gnome.org/lxr/source/libxslt/ChangeLog"
1375name="Changelog">Changelog</a></p>
1376
1377<h2><a name="Python">Python and bindings</a></h2>
1378
1379<p>There is a number of language bindings and wrappers available for libxml2,
1380the list below is not exhaustive. Please contact the <a
1381href="http://mail.gnome.org/mailman/listinfo/xml-bindings">xml-bindings@gnome.org</a>
1382(<a href="http://mail.gnome.org/archives/xml-bindings/">archives</a>) in
1383order to get updates to this list or to discuss the specific topic of libxml2
1384or libxslt wrappers or bindings:</p>
1385<ul>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]1386 <li><a href="mailto:ari@lusis.org">Ari Johnson</a> provides a C++ wrapper
1387 for libxml:<br>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1388 Website: <a
1389 href="http://lusis.org/~ari/xml++/">http://lusis.org/~ari/xml++/</a><br>
1390 Download: <a
1391 href="http://lusis.org/~ari/xml++/libxml++.tar.gz">http://lusis.org/~ari/xml++/libxml++.tar.gz</a></li>
1392 <li>There is another <a href="http://libgdome-cpp.berlios.de/">C++ wrapper
1393 based on the gdome2 </a>bindings maintained by Tobias Peters.</li>
Daniel Veillard9b6fd302002-05-13 12:06:47 +0000[diff] [blame]1394 <li>and a third C++ wrapper by Peter Jones &lt;pjones@pmade.org&gt;
1395 <p>Website: <a
1396 href="http://pmade.org/pjones/software/xmlwrapp/">http://pmade.org/pjones/software/xmlwrapp/</a></p>
1397 </li>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1398 <li><a
1399 href="http://mail.gnome.org/archives/xml/2001-March/msg00014.html">Matt
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]1400 Sergeant</a> developed <a
1401 href="http://axkit.org/download/">XML::LibXSLT</a>, a Perl wrapper for
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]1402 libxml2/libxslt as part of the <a href="http://axkit.com/">AxKit XML
1403 application server</a></li>
1404 <li><a href="mailto:dkuhlman@cutter.rexx.com">Dave Kuhlman</a> provides and
1405 earlier version of the libxml/libxslt <a
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1406 href="http://www.rexx.com/~dkuhlman">wrappers for Python</a></li>
1407 <li>Petr Kozelka provides <a
1408 href="http://sourceforge.net/projects/libxml2-pas">Pascal units to glue
1409 libxml2</a> with Kylix, Delphi and other Pascal compilers</li>
Daniel Veillardb2fb8ed2002-04-01 09:33:12 +0000[diff] [blame]1410 <li>Uwe Fechner also provides <a
1411 href="http://sourceforge.net/projects/idom2-pas/">idom2</a>, a DOM2
Daniel Veillard75794822002-04-11 16:24:32 +0000[diff] [blame]1412 implementation for Kylix2/D5/D6 from Borland</li>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1413 <li>Wai-Sun "Squidster" Chia provides <a
1414 href="http://www.rubycolor.org/arc/redist/">bindings for Ruby</a> and
1415 libxml2 bindings are also available in Ruby through the <a
1416 href="http://libgdome-ruby.berlios.de/">libgdome-ruby</a> module
1417 maintained by Tobias Peters.</li>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]1418 <li>Steve Ball and contributors maintains <a
1419 href="http://tclxml.sourceforge.net/">libxml2 and libxslt bindings for
1420 Tcl</a></li>
1421 <li>There is support for libxml2 in the DOM module of PHP.</li>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1422</ul>
1423
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]1424<p>The distribution includes a set of Python bindings, which are guaranteed to
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1425be maintained as part of the library in the future, though the Python
Daniel Veillard0b79dfe2002-02-23 13:02:31 +0000[diff] [blame]1426interface have not yet reached the maturity of the C API.</p>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]1427
1428<p>To install the Python bindings there are 2 options:</p>
Daniel Veillard0b79dfe2002-02-23 13:02:31 +0000[diff] [blame]1429<ul>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]1430 <li>If you use an RPM based distribution, simply install the <a
1431 href="http://rpmfind.net/linux/rpm2html/search.php?query=libxml2-python">libxml2-python
1432 RPM</a> (and if needed the <a
1433 href="http://rpmfind.net/linux/rpm2html/search.php?query=libxslt-python">libxslt-python
1434 RPM</a>).</li>
1435 <li>Otherwise use the <a href="ftp://xmlsoft.org/python/">libxml2-python
1436 module distribution</a> corresponding to your installed version of
1437 libxml2 and libxslt. Note that to install it you will need both libxml2
1438 and libxslt installed and run "python setup.py build install" in the
1439 module tree.</li>
Daniel Veillard0b79dfe2002-02-23 13:02:31 +0000[diff] [blame]1440</ul>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]1441
1442<p>The distribution includes a set of examples and regression tests for the
1443python bindings in the <code>python/tests</code> directory. Here are some
1444excepts from those tests:</p>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1445
1446<h3>tst.py:</h3>
1447
1448<p>This is a basic test of the file interface and DOM navigation:</p>
1449<pre>import libxml2
1450
1451doc = libxml2.parseFile("tst.xml")
1452if doc.name != "tst.xml":
1453 print "doc.name failed"
1454 sys.exit(1)
1455root = doc.children
1456if root.name != "doc":
1457 print "root.name failed"
1458 sys.exit(1)
1459child = root.children
1460if child.name != "foo":
1461 print "child.name failed"
1462 sys.exit(1)
1463doc.freeDoc()</pre>
1464
1465<p>The Python module is called libxml2, parseFile is the equivalent of
1466xmlParseFile (most of the bindings are automatically generated, and the xml
1467prefix is removed and the casing convention are kept). All node seen at the
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]1468binding level share the same subset of accessors:</p>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1469<ul>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]1470 <li><code>name</code> : returns the node name</li>
1471 <li><code>type</code> : returns a string indicating the node
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]1472 type</li>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]1473 <li><code>content</code> : returns the content of the node, it is based on
1474 xmlNodeGetContent() and hence is recursive.</li>
1475 <li><code>parent</code> , <code>children</code>, <code>last</code>,
1476 <code>next</code>, <code>prev</code>, <code>doc</code>,
1477 <code>properties</code>: pointing to the associated element in the tree,
1478 those may return None in case no such link exists.</li>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1479</ul>
1480
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]1481<p>Also note the need to explicitly deallocate documents with freeDoc() .
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1482Reference counting for libxml2 trees would need quite a lot of work to
1483function properly, and rather than risk memory leaks if not implemented
1484correctly it sounds safer to have an explicit function to free a tree. The
1485wrapper python objects like doc, root or child are them automatically garbage
1486collected.</p>
1487
1488<h3>validate.py:</h3>
1489
1490<p>This test check the validation interfaces and redirection of error
1491messages:</p>
1492<pre>import libxml2
1493
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]1494#deactivate error messages from the validation
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1495def noerr(ctx, str):
1496 pass
1497
1498libxml2.registerErrorHandler(noerr, None)
1499
1500ctxt = libxml2.createFileParserCtxt("invalid.xml")
1501ctxt.validate(1)
1502ctxt.parseDocument()
1503doc = ctxt.doc()
1504valid = ctxt.isValid()
1505doc.freeDoc()
1506if valid != 0:
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]1507 print "validity check failed"</pre>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1508
1509<p>The first thing to notice is the call to registerErrorHandler(), it
1510defines a new error handler global to the library. It is used to avoid seeing
1511the error messages when trying to validate the invalid document.</p>
1512
1513<p>The main interest of that test is the creation of a parser context with
1514createFileParserCtxt() and how the behaviour can be changed before calling
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]1515parseDocument() . Similarly the informations resulting from the parsing phase
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1516are also available using context methods.</p>
1517
1518<p>Contexts like nodes are defined as class and the libxml2 wrappers maps the
1519C function interfaces in terms of objects method as much as possible. The
1520best to get a complete view of what methods are supported is to look at the
1521libxml2.py module containing all the wrappers.</p>
1522
1523<h3>push.py:</h3>
1524
1525<p>This test show how to activate the push parser interface:</p>
1526<pre>import libxml2
1527
1528ctxt = libxml2.createPushParser(None, "&lt;foo", 4, "test.xml")
1529ctxt.parseChunk("/&gt;", 2, 1)
1530doc = ctxt.doc()
1531
1532doc.freeDoc()</pre>
1533
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]1534<p>The context is created with a special call based on the
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1535xmlCreatePushParser() from the C library. The first argument is an optional
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]1536SAX callback object, then the initial set of data, the length and the name of
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1537the resource in case URI-References need to be computed by the parser.</p>
1538
1539<p>Then the data are pushed using the parseChunk() method, the last call
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]1540setting the third argument terminate to 1.</p>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1541
1542<h3>pushSAX.py:</h3>
1543
1544<p>this test show the use of the event based parsing interfaces. In this case
1545the parser does not build a document, but provides callback information as
1546the parser makes progresses analyzing the data being provided:</p>
1547<pre>import libxml2
1548log = ""
1549
1550class callback:
1551 def startDocument(self):
1552 global log
1553 log = log + "startDocument:"
1554
1555 def endDocument(self):
1556 global log
1557 log = log + "endDocument:"
1558
1559 def startElement(self, tag, attrs):
1560 global log
1561 log = log + "startElement %s %s:" % (tag, attrs)
1562
1563 def endElement(self, tag):
1564 global log
1565 log = log + "endElement %s:" % (tag)
1566
1567 def characters(self, data):
1568 global log
1569 log = log + "characters: %s:" % (data)
1570
1571 def warning(self, msg):
1572 global log
1573 log = log + "warning: %s:" % (msg)
1574
1575 def error(self, msg):
1576 global log
1577 log = log + "error: %s:" % (msg)
1578
1579 def fatalError(self, msg):
1580 global log
1581 log = log + "fatalError: %s:" % (msg)
1582
1583handler = callback()
1584
1585ctxt = libxml2.createPushParser(handler, "&lt;foo", 4, "test.xml")
1586chunk = " url='tst'&gt;b"
1587ctxt.parseChunk(chunk, len(chunk), 0)
1588chunk = "ar&lt;/foo&gt;"
1589ctxt.parseChunk(chunk, len(chunk), 1)
1590
Daniel Veillardfcbfa2d2002-02-21 17:54:27 +0000[diff] [blame]1591reference = "startDocument:startElement foo {'url': 'tst'}:" + \
1592 "characters: bar:endElement foo:endDocument:"
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1593if log != reference:
1594 print "Error got: %s" % log
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]1595 print "Expected: %s" % reference</pre>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1596
1597<p>The key object in that test is the handler, it provides a number of entry
1598points which can be called by the parser as it makes progresses to indicate
1599the information set obtained. The full set of callback is larger than what
1600the callback class in that specific example implements (see the SAX
1601definition for a complete list). The wrapper will only call those supplied by
1602the object when activated. The startElement receives the names of the element
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]1603and a dictionary containing the attributes carried by this element.</p>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1604
1605<p>Also note that the reference string generated from the callback shows a
1606single character call even though the string "bar" is passed to the parser
1607from 2 different call to parseChunk()</p>
1608
1609<h3>xpath.py:</h3>
1610
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]1611<p>This is a basic test of XPath wrappers support</p>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1612<pre>import libxml2
1613
1614doc = libxml2.parseFile("tst.xml")
1615ctxt = doc.xpathNewContext()
1616res = ctxt.xpathEval("//*")
1617if len(res) != 2:
1618 print "xpath query: wrong node set size"
1619 sys.exit(1)
1620if res[0].name != "doc" or res[1].name != "foo":
1621 print "xpath query: wrong node set value"
1622 sys.exit(1)
1623doc.freeDoc()
1624ctxt.xpathFreeContext()</pre>
1625
1626<p>This test parses a file, then create an XPath context to evaluate XPath
1627expression on it. The xpathEval() method execute an XPath query and returns
1628the result mapped in a Python way. String and numbers are natively converted,
1629and node sets are returned as a tuple of libxml2 Python nodes wrappers. Like
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]1630the document, the XPath context need to be freed explicitly, also not that
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1631the result of the XPath query may point back to the document tree and hence
1632the document must be freed after the result of the query is used.</p>
1633
1634<h3>xpathext.py:</h3>
1635
1636<p>This test shows how to extend the XPath engine with functions written in
1637python:</p>
1638<pre>import libxml2
1639
1640def foo(ctx, x):
1641 return x + 1
1642
1643doc = libxml2.parseFile("tst.xml")
1644ctxt = doc.xpathNewContext()
1645libxml2.registerXPathFunction(ctxt._o, "foo", None, foo)
1646res = ctxt.xpathEval("foo(1)")
1647if res != 2:
1648 print "xpath extension failure"
1649doc.freeDoc()
1650ctxt.xpathFreeContext()</pre>
1651
1652<p>Note how the extension function is registered with the context (but that
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]1653part is not yet finalized, this may change slightly in the future).</p>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1654
1655<h3>tstxpath.py:</h3>
1656
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]1657<p>This test is similar to the previous one but shows how the extension
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1658function can access the XPath evaluation context:</p>
1659<pre>def foo(ctx, x):
1660 global called
1661
1662 #
1663 # test that access to the XPath evaluation contexts
1664 #
1665 pctxt = libxml2.xpathParserContext(_obj=ctx)
1666 ctxt = pctxt.context()
1667 called = ctxt.function()
1668 return x + 1</pre>
1669
1670<p>All the interfaces around the XPath parser(or rather evaluation) context
1671are not finalized, but it should be sufficient to do contextual work at the
1672evaluation point.</p>
1673
1674<h3>Memory debugging:</h3>
1675
1676<p>last but not least, all tests starts with the following prologue:</p>
1677<pre>#memory debug specific
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]1678libxml2.debugMemory(1)</pre>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1679
1680<p>and ends with the following epilogue:</p>
1681<pre>#memory debug specific
1682libxml2.cleanupParser()
1683if libxml2.debugMemory(1) == 0:
1684 print "OK"
1685else:
1686 print "Memory leak %d bytes" % (libxml2.debugMemory(1))
1687 libxml2.dumpMemory()</pre>
1688
1689<p>Those activate the memory debugging interface of libxml2 where all
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]1690allocated block in the library are tracked. The prologue then cleans up the
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1691library state and checks that all allocated memory has been freed. If not it
1692calls dumpMemory() which saves that list in a <code>.memdump</code> file.</p>
Daniel Veillard82687162001-01-22 15:32:01 +0000[diff] [blame]1693
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]1694<h2><a name="architecture">libxml architecture</a></h2>
Daniel Veillard4540be42000-08-19 16:40:28 +0000[diff] [blame]1695
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]1696<p>Libxml is made of multiple components; some of them are optional, and most
1697of the block interfaces are public. The main components are:</p>
Daniel Veillard4540be42000-08-19 16:40:28 +0000[diff] [blame]1698<ul>
1699 <li>an Input/Output layer</li>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]1700 <li>FTP and HTTP client layers (optional)</li>
Daniel Veillard4540be42000-08-19 16:40:28 +0000[diff] [blame]1701 <li>an Internationalization layer managing the encodings support</li>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]1702 <li>a URI module</li>
Daniel Veillard4540be42000-08-19 16:40:28 +0000[diff] [blame]1703 <li>the XML parser and its basic SAX interface</li>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]1704 <li>an HTML parser using the same SAX interface (optional)</li>
Daniel Veillard4540be42000-08-19 16:40:28 +0000[diff] [blame]1705 <li>a SAX tree module to build an in-memory DOM representation</li>
1706 <li>a tree module to manipulate the DOM representation</li>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]1707 <li>a validation module using the DOM representation (optional)</li>
Daniel Veillard4540be42000-08-19 16:40:28 +0000[diff] [blame]1708 <li>an XPath module for global lookup in a DOM representation
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]1709 (optional)</li>
1710 <li>a debug module (optional)</li>
Daniel Veillard4540be42000-08-19 16:40:28 +0000[diff] [blame]1711</ul>
1712
1713<p>Graphically this gives the following:</p>
1714
1715<p><img src="libxml.gif" alt="a graphical view of the various"></p>
1716
1717<p></p>
1718
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]1719<h2><a name="tree">The tree output</a></h2>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1720
1721<p>The parser returns a tree built during the document analysis. The value
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]1722returned is an <strong>xmlDocPtr</strong> (i.e., a pointer to an
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1723<strong>xmlDoc</strong> structure). This structure contains information such
Daniel Veillard306be992000-07-03 12:38:45 +0000[diff] [blame]1724as the file name, the document type, and a <strong>children</strong> pointer
1725which is the root of the document (or more exactly the first child under the
1726root which is the document). The tree is made of <strong>xmlNode</strong>s,
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]1727chained in double-linked lists of siblings and with a children&lt;-&gt;parent
Daniel Veillard306be992000-07-03 12:38:45 +0000[diff] [blame]1728relationship. An xmlNode can also carry properties (a chain of xmlAttr
1729structures). An attribute may have a value which is a list of TEXT or
1730ENTITY_REF nodes.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1731
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1732<p>Here is an example (erroneous with respect to the XML spec since there
1733should be only one ELEMENT under the root):</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1734
1735<p><img src="structure.gif" alt=" structure.gif "></p>
1736
1737<p>In the source package there is a small program (not installed by default)
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]1738called <strong>xmllint</strong> which parses XML files given as argument and
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1739prints them back as parsed. This is useful for detecting errors both in XML
1740code and in the XML parser itself. It has an option <strong>--debug</strong>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]1741which prints the actual in-memory structure of the document; here is the
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1742result with the <a href="#example">example</a> given before:</p>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]1743<pre>DOCUMENT
1744version=1.0
1745standalone=true
1746 ELEMENT EXAMPLE
1747 ATTRIBUTE prop1
1748 TEXT
1749 content=gnome is great
1750 ATTRIBUTE prop2
1751 ENTITY_REF
1752 TEXT
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]1753 content= linux too
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]1754 ELEMENT head
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]1755 ELEMENT title
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]1756 TEXT
1757 content=Welcome to Gnome
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]1758 ELEMENT chapter
1759 ELEMENT title
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]1760 TEXT
1761 content=The Linux adventure
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]1762 ELEMENT p
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]1763 TEXT
1764 content=bla bla bla ...
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]1765 ELEMENT image
1766 ATTRIBUTE href
1767 TEXT
1768 content=linus.gif
1769 ELEMENT p
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]1770 TEXT
1771 content=...</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1772
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1773<p>This should be useful for learning the internal representation model.</p>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]1774
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]1775<h2><a name="interface">The SAX interface</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1776
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]1777<p>Sometimes the DOM tree output is just too large to fit reasonably into
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1778memory. 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]1779loaded using libxml), it's better to use the SAX interface of libxml. SAX is
1780a <strong>callback-based interface</strong> to the parser. Before parsing,
1781the application layer registers a customized set of callbacks which are
1782called by the library as it progresses through the XML input.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1783
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1784<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]1785libxml, see the <a
1786href="http://www.daa.com.au/~james/gnome/xml-sax/xml-sax.html">nice
1787documentation</a>.written by <a href="mailto:james@daa.com.au">James
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1788Henstridge</a>.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1789
1790<p>You can debug the SAX behaviour by using the <strong>testSAX</strong>
1791program located in the gnome-xml module (it's usually not shipped in the
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1792binary packages of libxml, but you can find it in the tar source
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]1793distribution). Here is the sequence of callbacks that would be reported by
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1794testSAX when parsing the example XML document shown earlier:</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1795<pre>SAX.setDocumentLocator()
1796SAX.startDocument()
1797SAX.getEntity(amp)
1798SAX.startElement(EXAMPLE, prop1='gnome is great', prop2='&amp;amp; linux too')
1799SAX.characters( , 3)
1800SAX.startElement(head)
1801SAX.characters( , 4)
1802SAX.startElement(title)
1803SAX.characters(Welcome to Gnome, 16)
1804SAX.endElement(title)
1805SAX.characters( , 3)
1806SAX.endElement(head)
1807SAX.characters( , 3)
1808SAX.startElement(chapter)
1809SAX.characters( , 4)
1810SAX.startElement(title)
1811SAX.characters(The Linux adventure, 19)
1812SAX.endElement(title)
1813SAX.characters( , 4)
1814SAX.startElement(p)
1815SAX.characters(bla bla bla ..., 15)
1816SAX.endElement(p)
1817SAX.characters( , 4)
1818SAX.startElement(image, href='linus.gif')
1819SAX.endElement(image)
1820SAX.characters( , 4)
1821SAX.startElement(p)
1822SAX.characters(..., 3)
1823SAX.endElement(p)
1824SAX.characters( , 3)
1825SAX.endElement(chapter)
1826SAX.characters( , 1)
1827SAX.endElement(EXAMPLE)
1828SAX.endDocument()</pre>
1829
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]1830<p>Most of the other interfaces of libxml are based on the DOM tree-building
1831facility, so nearly everything up to the end of this document presupposes the
1832use of the standard DOM tree build. Note that the DOM tree itself is built by
1833a set of registered default callbacks, without internal specific
1834interface.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1835
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]1836<h2><a name="Validation">Validation &amp; DTDs</a></h2>
1837
1838<p>Table of Content:</p>
1839<ol>
1840 <li><a href="#General5">General overview</a></li>
1841 <li><a href="#definition">The definition</a></li>
1842 <li><a href="#Simple">Simple rules</a>
1843 <ol>
Daniel Veillard9c466822001-10-25 12:03:39 +0000[diff] [blame]1844 <li><a href="#reference">How to reference a DTD from a document</a></li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]1845 <li><a href="#Declaring">Declaring elements</a></li>
1846 <li><a href="#Declaring1">Declaring attributes</a></li>
1847 </ol>
1848 </li>
1849 <li><a href="#Some">Some examples</a></li>
1850 <li><a href="#validate">How to validate</a></li>
1851 <li><a href="#Other">Other resources</a></li>
1852</ol>
1853
1854<h3><a name="General5">General overview</a></h3>
1855
1856<p>Well what is validation and what is a DTD ?</p>
1857
1858<p>DTD is the acronym for Document Type Definition. This is a description of
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]1859the content for a family of XML files. This is part of the XML 1.0
1860specification, and allows to describe and check that a given document instance
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]1861conforms to a set of rules detailing its structure and content.</p>
1862
1863<p>Validation is the process of checking a document against a DTD (more
1864generally against a set of construction rules).</p>
1865
1866<p>The validation process and building DTDs are the two most difficult parts
1867of the XML life cycle. Briefly a DTD defines all the possibles element to be
1868found within your document, what is the formal shape of your document tree
1869(by defining the allowed content of an element, either text, a regular
1870expression for the allowed list of children, or mixed content i.e. both text
1871and children). The DTD also defines the allowed attributes for all elements
1872and the types of the attributes.</p>
1873
1874<h3><a name="definition1">The definition</a></h3>
1875
1876<p>The <a href="http://www.w3.org/TR/REC-xml">W3C XML Recommendation</a> (<a
1877href="http://www.xml.com/axml/axml.html">Tim Bray's annotated version of
1878Rev1</a>):</p>
1879<ul>
1880 <li><a href="http://www.w3.org/TR/REC-xml#elemdecls">Declaring
1881 elements</a></li>
1882 <li><a href="http://www.w3.org/TR/REC-xml#attdecls">Declaring
1883 attributes</a></li>
1884</ul>
1885
1886<p>(unfortunately) all this is inherited from the SGML world, the syntax is
1887ancient...</p>
1888
1889<h3><a name="Simple1">Simple rules</a></h3>
1890
1891<p>Writing DTD can be done in multiple ways, the rules to build them if you
1892need something fixed or something which can evolve over time can be radically
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]1893different. Really complex DTD like DocBook ones are flexible but quite harder
1894to design. I will just focus on DTDs for a formats with a fixed simple
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]1895structure. It is just a set of basic rules, and definitely not exhaustive nor
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]1896usable for complex DTD design.</p>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]1897
1898<h4><a name="reference1">How to reference a DTD from a document</a>:</h4>
1899
1900<p>Assuming the top element of the document is <code>spec</code> and the dtd
1901is placed in the file <code>mydtd</code> in the subdirectory
1902<code>dtds</code> of the directory from where the document were loaded:</p>
1903
1904<p><code>&lt;!DOCTYPE spec SYSTEM "dtds/mydtd"&gt;</code></p>
1905
1906<p>Notes:</p>
1907<ul>
1908 <li>the system string is actually an URI-Reference (as defined in <a
1909 href="http://www.ietf.org/rfc/rfc2396.txt">RFC 2396</a>) so you can use a
1910 full URL string indicating the location of your DTD on the Web, this is a
1911 really good thing to do if you want others to validate your document</li>
1912 <li>it is also possible to associate a <code>PUBLIC</code> identifier (a
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]1913 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]1914 without having to locate it on the web</li>
1915 <li>a dtd contains a set of elements and attributes declarations, but they
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]1916 don't define what the root of the document should be. This is explicitly
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]1917 told to the parser/validator as the first element of the
1918 <code>DOCTYPE</code> declaration.</li>
1919</ul>
1920
1921<h4><a name="Declaring2">Declaring elements</a>:</h4>
1922
1923<p>The following declares an element <code>spec</code>:</p>
1924
1925<p><code>&lt;!ELEMENT spec (front, body, back?)&gt;</code></p>
1926
1927<p>it also expresses that the spec element contains one <code>front</code>,
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]1928one <code>body</code> and one optional <code>back</code> children elements
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]1929in this order. The declaration of one element of the structure and its
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]1930content are done in a single declaration. Similarly the following declares
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]1931<code>div1</code> elements:</p>
1932
Daniel Veillard51737272002-01-23 23:10:38 +0000[diff] [blame]1933<p><code>&lt;!ELEMENT div1 (head, (p | list | note)*, div2?)&gt;</code></p>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]1934
1935<p>means div1 contains one <code>head</code> then a series of optional
1936<code>p</code>, <code>list</code>s and <code>note</code>s and then an
1937optional <code>div2</code>. And last but not least an element can contain
1938text:</p>
1939
1940<p><code>&lt;!ELEMENT b (#PCDATA)&gt;</code></p>
1941
1942<p><code>b</code> contains text or being of mixed content (text and elements
1943in no particular order):</p>
1944
1945<p><code>&lt;!ELEMENT p (#PCDATA|a|ul|b|i|em)*&gt;</code></p>
1946
1947<p><code>p </code>can contain text or <code>a</code>, <code>ul</code>,
1948<code>b</code>, <code>i </code>or <code>em</code> elements in no particular
1949order.</p>
1950
1951<h4><a name="Declaring1">Declaring attributes</a>:</h4>
1952
1953<p>again the attributes declaration includes their content definition:</p>
1954
1955<p><code>&lt;!ATTLIST termdef name CDATA #IMPLIED&gt;</code></p>
1956
1957<p>means that the element <code>termdef</code> can have a <code>name</code>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]1958attribute containing text (<code>CDATA</code>) and which is optional
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]1959(<code>#IMPLIED</code>). The attribute value can also be defined within a
1960set:</p>
1961
1962<p><code>&lt;!ATTLIST list type (bullets|ordered|glossary)
1963"ordered"&gt;</code></p>
1964
1965<p>means <code>list</code> element have a <code>type</code> attribute with 3
1966allowed values "bullets", "ordered" or "glossary" and which default to
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]1967"ordered" if the attribute is not explicitly specified.</p>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]1968
1969<p>The content type of an attribute can be text (<code>CDATA</code>),
1970anchor/reference/references
1971(<code>ID</code>/<code>IDREF</code>/<code>IDREFS</code>), entity(ies)
1972(<code>ENTITY</code>/<code>ENTITIES</code>) or name(s)
1973(<code>NMTOKEN</code>/<code>NMTOKENS</code>). The following defines that a
1974<code>chapter</code> element can have an optional <code>id</code> attribute
1975of type <code>ID</code>, usable for reference from attribute of type
1976IDREF:</p>
1977
1978<p><code>&lt;!ATTLIST chapter id ID #IMPLIED&gt;</code></p>
1979
1980<p>The last value of an attribute definition can be <code>#REQUIRED
1981</code>meaning that the attribute has to be given, <code>#IMPLIED</code>
1982meaning that it is optional, or the default value (possibly prefixed by
1983<code>#FIXED</code> if it is the only allowed).</p>
1984
1985<p>Notes:</p>
1986<ul>
1987 <li>usually the attributes pertaining to a given element are declared in a
1988 single expression, but it is just a convention adopted by a lot of DTD
1989 writers:
1990 <pre>&lt;!ATTLIST termdef
1991 id ID #REQUIRED
1992 name CDATA #IMPLIED&gt;</pre>
1993 <p>The previous construct defines both <code>id</code> and
1994 <code>name</code> attributes for the element <code>termdef</code></p>
1995 </li>
1996</ul>
1997
1998<h3><a name="Some1">Some examples</a></h3>
1999
2000<p>The directory <code>test/valid/dtds/</code> in the libxml distribution
2001contains some complex DTD examples. The <code>test/valid/dia.xml</code>
2002example shows an XML file where the simple DTD is directly included within
2003the document.</p>
2004
2005<h3><a name="validate1">How to validate</a></h3>
2006
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]2007<p>The simplest is to use the xmllint program coming with libxml. The
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2008<code>--valid</code> option turn on validation of the files given as input,
2009for example the following validates a copy of the first revision of the XML
20101.0 specification:</p>
2011
2012<p><code>xmllint --valid --noout test/valid/REC-xml-19980210.xml</code></p>
2013
2014<p>the -- noout is used to not output the resulting tree.</p>
2015
2016<p>The <code>--dtdvalid dtd</code> allows to validate the document(s) against
2017a given DTD.</p>
2018
2019<p>Libxml exports an API to handle DTDs and validation, check the <a
2020href="http://xmlsoft.org/html/libxml-valid.html">associated
2021description</a>.</p>
2022
2023<h3><a name="Other1">Other resources</a></h3>
2024
2025<p>DTDs are as old as SGML. So there may be a number of examples on-line, I
2026will just list one for now, others pointers welcome:</p>
2027<ul>
2028 <li><a href="http://www.xml101.com:8081/dtd/">XML-101 DTD</a></li>
2029</ul>
2030
2031<p>I suggest looking at the examples found under test/valid/dtd and any of
2032the large number of books available on XML. The dia example in test/valid
2033should be both simple and complete enough to allow you to build your own.</p>
2034
2035<p></p>
2036
2037<h2><a name="Memory">Memory Management</a></h2>
2038
2039<p>Table of Content:</p>
2040<ol>
2041 <li><a href="#General3">General overview</a></li>
Daniel Veillard9c466822001-10-25 12:03:39 +0000[diff] [blame]2042 <li><a href="#setting">Setting libxml set of memory routines</a></li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2043 <li><a href="#cleanup">Cleaning up after parsing</a></li>
2044 <li><a href="#Debugging">Debugging routines</a></li>
2045 <li><a href="#General4">General memory requirements</a></li>
2046</ol>
2047
2048<h3><a name="General3">General overview</a></h3>
2049
2050<p>The module <code><a
2051href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlmemory.h</a></code>
2052provides the interfaces to the libxml memory system:</p>
2053<ul>
2054 <li>libxml does not use the libc memory allocator directly but xmlFree(),
2055 xmlMalloc() and xmlRealloc()</li>
2056 <li>those routines can be reallocated to a specific set of routine, by
2057 default the libc ones i.e. free(), malloc() and realloc()</li>
2058 <li>the xmlmemory.c module includes a set of debugging routine</li>
2059</ul>
2060
2061<h3><a name="setting">Setting libxml set of memory routines</a></h3>
2062
2063<p>It is sometimes useful to not use the default memory allocator, either for
2064debugging, analysis or to implement a specific behaviour on memory management
2065(like on embedded systems). Two function calls are available to do so:</p>
2066<ul>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]2067 <li><a href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlMemGet
2068 ()</a> which return the current set of functions in use by the parser</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2069 <li><a
2070 href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlMemSetup()</a>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]2071 which allow to set up a new set of memory allocation functions</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2072</ul>
2073
2074<p>Of course a call to xmlMemSetup() should probably be done before calling
2075any other libxml routines (unless you are sure your allocations routines are
2076compatibles).</p>
2077
2078<h3><a name="cleanup">Cleaning up after parsing</a></h3>
2079
2080<p>Libxml is not stateless, there is a few set of memory structures needing
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]2081allocation before the parser is fully functional (some encoding structures
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2082for example). This also mean that once parsing is finished there is a tiny
2083amount of memory (a few hundred bytes) which can be recollected if you don't
2084reuse the parser immediately:</p>
2085<ul>
2086 <li><a href="http://xmlsoft.org/html/libxml-parser.html">xmlCleanupParser
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]2087 ()</a> is a centralized routine to free the parsing states. Note that it
2088 won't deallocate any produced tree if any (use the xmlFreeDoc() and
2089 related routines for this).</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2090 <li><a href="http://xmlsoft.org/html/libxml-parser.html">xmlInitParser
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]2091 ()</a> is the dual routine allowing to preallocate the parsing state
2092 which can be useful for example to avoid initialization reentrancy
2093 problems when using libxml in multithreaded applications</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2094</ul>
2095
2096<p>Generally xmlCleanupParser() is safe, if needed the state will be rebuild
2097at the next invocation of parser routines, but be careful of the consequences
2098in multithreaded applications.</p>
2099
2100<h3><a name="Debugging">Debugging routines</a></h3>
2101
2102<p>When configured using --with-mem-debug flag (off by default), libxml uses
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]2103a set of memory allocation debugging routines keeping track of all allocated
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2104blocks and the location in the code where the routine was called. A couple of
2105other debugging routines allow to dump the memory allocated infos to a file
2106or call a specific routine when a given block number is allocated:</p>
2107<ul>
2108 <li><a
2109 href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlMallocLoc()</a>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]2110 <a
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2111 href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlReallocLoc()</a>
2112 and <a
2113 href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlMemStrdupLoc()</a>
2114 are the memory debugging replacement allocation routines</li>
2115 <li><a href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlMemoryDump
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]2116 ()</a> dumps all the informations about the allocated memory block lefts
2117 in the <code>.memdump</code> file</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2118</ul>
2119
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]2120<p>When developing libxml memory debug is enabled, the tests programs call
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2121xmlMemoryDump () and the "make test" regression tests will check for any
2122memory leak during the full regression test sequence, this helps a lot
2123ensuring that libxml does not leak memory and bullet proof memory
2124allocations use (some libc implementations are known to be far too permissive
2125resulting in major portability problems!).</p>
2126
2127<p>If the .memdump reports a leak, it displays the allocation function and
2128also tries to give some informations about the content and structure of the
2129allocated blocks left. This is sufficient in most cases to find the culprit,
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]2130but not always. Assuming the allocation problem is reproducible, it is
2131possible to find more easily:</p>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2132<ol>
2133 <li>write down the block number xxxx not allocated</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]2134 <li>export the environment variable XML_MEM_BREAKPOINT=xxxx , the easiest
Daniel Veillard75794822002-04-11 16:24:32 +0000[diff] [blame]2135 when using GDB is to simply give the command
2136 <p><code>set environment XML_MEM_BREAKPOINT xxxx</code></p>
2137 <p>before running the program.</p>
2138 </li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2139 <li>run the program under a debugger and set a breakpoint on
2140 xmlMallocBreakpoint() a specific function called when this precise block
2141 is allocated</li>
2142 <li>when the breakpoint is reached you can then do a fine analysis of the
2143 allocation an step to see the condition resulting in the missing
2144 deallocation.</li>
2145</ol>
2146
2147<p>I used to use a commercial tool to debug libxml memory problems but after
2148noticing that it was not detecting memory leaks that simple mechanism was
Daniel Veillard75794822002-04-11 16:24:32 +0000[diff] [blame]2149used and proved extremely efficient until now. Lately I have also used <a
2150href="http://developer.kde.org/~sewardj/">valgrind</a> with quite some
2151success, it is tied to the i386 architecture since it works by emulating the
2152processor and instruction set, it is slow but extremely efficient, i.e. it
2153spot memory usage errors in a very precise way.</p>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2154
2155<h3><a name="General4">General memory requirements</a></h3>
2156
2157<p>How much libxml memory require ? It's hard to tell in average it depends
2158of a number of things:</p>
2159<ul>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]2160 <li>the parser itself should work in a fixed amount of memory, except for
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2161 information maintained about the stacks of names and entities locations.
2162 The I/O and encoding handlers will probably account for a few KBytes.
2163 This is true for both the XML and HTML parser (though the HTML parser
2164 need more state).</li>
2165 <li>If you are generating the DOM tree then memory requirements will grow
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]2166 nearly linear with the size of the data. In general for a balanced
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2167 textual document the internal memory requirement is about 4 times the
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]2168 size of the UTF8 serialization of this document (example the XML-1.0
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2169 recommendation is a bit more of 150KBytes and takes 650KBytes of main
2170 memory when parsed). Validation will add a amount of memory required for
2171 maintaining the external Dtd state which should be linear with the
2172 complexity of the content model defined by the Dtd</li>
2173 <li>If you don't care about the advanced features of libxml like
2174 validation, DOM, XPath or XPointer, but really need to work fixed memory
2175 requirements, then the SAX interface should be used.</li>
2176</ul>
2177
2178<p></p>
2179
2180<h2><a name="Encodings">Encodings support</a></h2>
2181
2182<p>Table of Content:</p>
2183<ol>
2184 <li><a href="encoding.html#What">What does internationalization support
2185 mean ?</a></li>
2186 <li><a href="encoding.html#internal">The internal encoding, how and
2187 why</a></li>
2188 <li><a href="encoding.html#implemente">How is it implemented ?</a></li>
2189 <li><a href="encoding.html#Default">Default supported encodings</a></li>
2190 <li><a href="encoding.html#extend">How to extend the existing
2191 support</a></li>
2192</ol>
2193
2194<h3><a name="What">What does internationalization support mean ?</a></h3>
2195
2196<p>XML was designed from the start to allow the support of any character set
2197by using Unicode. Any conformant XML parser has to support the UTF-8 and
2198UTF-16 default encodings which can both express the full unicode ranges. UTF8
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]2199is a variable length encoding whose greatest points are to reuse the same
2200encoding for ASCII and to save space for Western encodings, but it is a bit
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2201more complex to handle in practice. UTF-16 use 2 bytes per characters (and
2202sometimes combines two pairs), it makes implementation easier, but looks a
2203bit overkill for Western languages encoding. Moreover the XML specification
2204allows document to be encoded in other encodings at the condition that they
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]2205are clearly labeled as such. For example the following is a wellformed XML
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2206document encoded in ISO-8859 1 and using accentuated letter that we French
2207likes for both markup and content:</p>
2208<pre>&lt;?xml version="1.0" encoding="ISO-8859-1"?&gt;
2209&lt;très&gt;là&lt;/très&gt;</pre>
2210
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]2211<p>Having internationalization support in libxml means the following:</p>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2212<ul>
2213 <li>the document is properly parsed</li>
2214 <li>informations about it's encoding are saved</li>
2215 <li>it can be modified</li>
2216 <li>it can be saved in its original encoding</li>
2217 <li>it can also be saved in another encoding supported by libxml (for
2218 example straight UTF8 or even an ASCII form)</li>
2219</ul>
2220
2221<p>Another very important point is that the whole libxml API, with the
2222exception of a few routines to read with a specific encoding or save to a
2223specific encoding, is completely agnostic about the original encoding of the
2224document.</p>
2225
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]2226<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]2227the same rules too, the following document will be (as of 2.2.2) handled in
2228an internationalized fashion by libxml too:</p>
2229<pre>&lt;!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"
2230 "http://www.w3.org/TR/REC-html40/loose.dtd"&gt;
2231&lt;html lang="fr"&gt;
2232&lt;head&gt;
2233 &lt;META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=ISO-8859-1"&gt;
2234&lt;/head&gt;
2235&lt;body&gt;
2236&lt;p&gt;W3C crée des standards pour le Web.&lt;/body&gt;
2237&lt;/html&gt;</pre>
2238
2239<h3><a name="internal">The internal encoding, how and why</a></h3>
2240
2241<p>One of the core decision was to force all documents to be converted to a
2242default internal encoding, and that encoding to be UTF-8, here are the
2243rationale for those choices:</p>
2244<ul>
2245 <li>keeping the native encoding in the internal form would force the libxml
2246 users (or the code associated) to be fully aware of the encoding of the
2247 original document, for examples when adding a text node to a document,
2248 the content would have to be provided in the document encoding, i.e. the
2249 client code would have to check it before hand, make sure it's conformant
2250 to the encoding, etc ... Very hard in practice, though in some specific
2251 cases this may make sense.</li>
2252 <li>the second decision was which encoding. From the XML spec only UTF8 and
2253 UTF16 really makes sense as being the two only encodings for which there
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]2254 is mandatory support. UCS-4 (32 bits fixed size encoding) could be
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2255 considered an intelligent choice too since it's a direct Unicode mapping
2256 support. I selected UTF-8 on the basis of efficiency and compatibility
2257 with surrounding software:
2258 <ul>
2259 <li>UTF-8 while a bit more complex to convert from/to (i.e. slightly
2260 more costly to import and export CPU wise) is also far more compact
2261 than UTF-16 (and UCS-4) for a majority of the documents I see it used
2262 for right now (RPM RDF catalogs, advogato data, various configuration
2263 file formats, etc.) and the key point for today's computer
2264 architecture is efficient uses of caches. If one nearly double the
2265 memory requirement to store the same amount of data, this will trash
2266 caches (main memory/external caches/internal caches) and my take is
2267 that this harms the system far more than the CPU requirements needed
2268 for the conversion to UTF-8</li>
2269 <li>Most of libxml version 1 users were using it with straight ASCII
2270 most of the time, doing the conversion with an internal encoding
2271 requiring all their code to be rewritten was a serious show-stopper
2272 for using UTF-16 or UCS-4.</li>
2273 <li>UTF-8 is being used as the de-facto internal encoding standard for
2274 related code like the <a href="http://www.pango.org/">pango</a>
2275 upcoming Gnome text widget, and a lot of Unix code (yep another place
2276 where Unix programmer base takes a different approach from Microsoft
2277 - they are using UTF-16)</li>
2278 </ul>
2279 </li>
2280</ul>
2281
2282<p>What does this mean in practice for the libxml user:</p>
2283<ul>
2284 <li>xmlChar, the libxml data type is a byte, those bytes must be assembled
2285 as UTF-8 valid strings. The proper way to terminate an xmlChar * string
2286 is simply to append 0 byte, as usual.</li>
2287 <li>One just need to make sure that when using chars outside the ASCII set,
2288 the values has been properly converted to UTF-8</li>
2289</ul>
2290
2291<h3><a name="implemente">How is it implemented ?</a></h3>
2292
2293<p>Let's describe how all this works within libxml, basically the I18N
2294(internationalization) support get triggered only during I/O operation, i.e.
2295when reading a document or saving one. Let's look first at the reading
2296sequence:</p>
2297<ol>
2298 <li>when a document is processed, we usually don't know the encoding, a
2299 simple heuristic allows to detect UTF-18 and UCS-4 from whose where the
2300 ASCII range (0-0x7F) maps with ASCII</li>
2301 <li>the xml declaration if available is parsed, including the encoding
2302 declaration. At that point, if the autodetected encoding is different
2303 from the one declared a call to xmlSwitchEncoding() is issued.</li>
2304 <li>If there is no encoding declaration, then the input has to be in either
2305 UTF-8 or UTF-16, if it is not then at some point when processing the
2306 input, the converter/checker of UTF-8 form will raise an encoding error.
2307 You may end-up with a garbled document, or no document at all ! Example:
2308 <pre>~/XML -&gt; ./xmllint err.xml
2309err.xml:1: error: Input is not proper UTF-8, indicate encoding !
2310&lt;très&gt;là&lt;/très&gt;
2311 ^
2312err.xml:1: error: Bytes: 0xE8 0x73 0x3E 0x6C
2313&lt;très&gt;là&lt;/très&gt;
2314 ^</pre>
2315 </li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]2316 <li>xmlSwitchEncoding() does an encoding name lookup, canonicalize it, and
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2317 then search the default registered encoding converters for that encoding.
2318 If it's not within the default set and iconv() support has been compiled
2319 it, it will ask iconv for such an encoder. If this fails then the parser
2320 will report an error and stops processing:
2321 <pre>~/XML -&gt; ./xmllint err2.xml
2322err2.xml:1: error: Unsupported encoding UnsupportedEnc
2323&lt;?xml version="1.0" encoding="UnsupportedEnc"?&gt;
2324 ^</pre>
2325 </li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]2326 <li>From that point the encoder processes progressingly the input (it is
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2327 plugged as a front-end to the I/O module) for that entity. It captures
2328 and convert on-the-fly the document to be parsed to UTF-8. The parser
2329 itself just does UTF-8 checking of this input and process it
2330 transparently. The only difference is that the encoding information has
2331 been added to the parsing context (more precisely to the input
2332 corresponding to this entity).</li>
2333 <li>The result (when using DOM) is an internal form completely in UTF-8
2334 with just an encoding information on the document node.</li>
2335</ol>
2336
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]2337<p>Ok then what happens when saving the document (assuming you
2338collected/built an xmlDoc DOM like structure) ? It depends on the function
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2339called, xmlSaveFile() will just try to save in the original encoding, while
2340xmlSaveFileTo() and xmlSaveFileEnc() can optionally save to a given
2341encoding:</p>
2342<ol>
2343 <li>if no encoding is given, libxml will look for an encoding value
2344 associated to the document and if it exists will try to save to that
2345 encoding,
2346 <p>otherwise everything is written in the internal form, i.e. UTF-8</p>
2347 </li>
2348 <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^]2349 document, libxml will again canonicalize the encoding name, lookup for a
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2350 converter in the registered set or through iconv. If not found the
2351 function will return an error code</li>
2352 <li>the converter is placed before the I/O buffer layer, as another kind of
2353 buffer, then libxml will simply push the UTF-8 serialization to through
2354 that buffer, which will then progressively be converted and pushed onto
2355 the I/O layer.</li>
2356 <li>It is possible that the converter code fails on some input, for example
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]2357 trying to push an UTF-8 encoded Chinese character through the UTF-8 to
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2358 ISO-8859-1 converter won't work. Since the encoders are progressive they
2359 will just report the error and the number of bytes converted, at that
2360 point libxml will decode the offending character, remove it from the
2361 buffer and replace it with the associated charRef encoding &amp;#123; and
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]2362 resume the conversion. This guarantees that any document will be saved
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2363 without losses (except for markup names where this is not legal, this is
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]2364 a problem in the current version, in practice avoid using non-ascii
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2365 characters for tags or attributes names @@). A special "ascii" encoding
2366 name is used to save documents to a pure ascii form can be used when
2367 portability is really crucial</li>
2368</ol>
2369
2370<p>Here is a few examples based on the same test document:</p>
2371<pre>~/XML -&gt; ./xmllint isolat1
2372&lt;?xml version="1.0" encoding="ISO-8859-1"?&gt;
2373&lt;très&gt;là&lt;/très&gt;
2374~/XML -&gt; ./xmllint --encode UTF-8 isolat1
2375&lt;?xml version="1.0" encoding="UTF-8"?&gt;
2376&lt;très&gt;là  &lt;/très&gt;
2377~/XML -&gt; </pre>
2378
2379<p>The same processing is applied (and reuse most of the code) for HTML I18N
2380processing. Looking up and modifying the content encoding is a bit more
2381difficult since it is located in a &lt;meta&gt; tag under the &lt;head&gt;,
2382so a couple of functions htmlGetMetaEncoding() and htmlSetMetaEncoding() have
2383been provided. The parser also attempts to switch encoding on the fly when
2384detecting such a tag on input. Except for that the processing is the same
2385(and again reuses the same code).</p>
2386
2387<h3><a name="Default">Default supported encodings</a></h3>
2388
2389<p>libxml has a set of default converters for the following encodings
2390(located in encoding.c):</p>
2391<ol>
2392 <li>UTF-8 is supported by default (null handlers)</li>
2393 <li>UTF-16, both little and big endian</li>
2394 <li>ISO-Latin-1 (ISO-8859-1) covering most western languages</li>
2395 <li>ASCII, useful mostly for saving</li>
2396 <li>HTML, a specific handler for the conversion of UTF-8 to ASCII with HTML
2397 predefined entities like &amp;copy; for the Copyright sign.</li>
2398</ol>
2399
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]2400<p>More over when compiled on an Unix platform with iconv support the full set
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2401of encodings supported by iconv can be instantly be used by libxml. On a
2402linux machine with glibc-2.1 the list of supported encodings and aliases fill
24033 full pages, and include UCS-4, the full set of ISO-Latin encodings, and the
2404various Japanese ones.</p>
2405
2406<h4>Encoding aliases</h4>
2407
2408<p>From 2.2.3, libxml has support to register encoding names aliases. The
2409goal is to be able to parse document whose encoding is supported but where
2410the name differs (for example from the default set of names accepted by
2411iconv). The following functions allow to register and handle new aliases for
2412existing encodings. Once registered libxml will automatically lookup the
2413aliases when handling a document:</p>
2414<ul>
2415 <li>int xmlAddEncodingAlias(const char *name, const char *alias);</li>
2416 <li>int xmlDelEncodingAlias(const char *alias);</li>
2417 <li>const char * xmlGetEncodingAlias(const char *alias);</li>
2418 <li>void xmlCleanupEncodingAliases(void);</li>
2419</ul>
2420
2421<h3><a name="extend">How to extend the existing support</a></h3>
2422
2423<p>Well adding support for new encoding, or overriding one of the encoders
2424(assuming it is buggy) should not be hard, just write an input and output
2425conversion routines to/from UTF-8, and register them using
2426xmlNewCharEncodingHandler(name, xxxToUTF8, UTF8Toxxx), and they will be
2427called automatically if the parser(s) encounter such an encoding name
2428(register it uppercase, this will help). The description of the encoders,
2429their arguments and expected return values are described in the encoding.h
2430header.</p>
2431
2432<p>A quick note on the topic of subverting the parser to use a different
2433internal encoding than UTF-8, in some case people will absolutely want to
2434keep the internal encoding different, I think it's still possible (but the
2435encoding must be compliant with ASCII on the same subrange) though I didn't
2436tried it. The key is to override the default conversion routines (by
2437registering null encoders/decoders for your charsets), and bypass the UTF-8
2438checking of the parser by setting the parser context charset
2439(ctxt-&gt;charset) to something different than XML_CHAR_ENCODING_UTF8, but
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]2440there is no guarantee that this will work. You may also have some troubles
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2441saving back.</p>
2442
2443<p>Basically proper I18N support is important, this requires at least
2444libxml-2.0.0, but a lot of features and corrections are really available only
2445starting 2.2.</p>
2446
2447<h2><a name="IO">I/O Interfaces</a></h2>
2448
2449<p>Table of Content:</p>
2450<ol>
2451 <li><a href="#General1">General overview</a></li>
2452 <li><a href="#basic">The basic buffer type</a></li>
2453 <li><a href="#Input">Input I/O handlers</a></li>
2454 <li><a href="#Output">Output I/O handlers</a></li>
2455 <li><a href="#entities">The entities loader</a></li>
2456 <li><a href="#Example2">Example of customized I/O</a></li>
2457</ol>
2458
2459<h3><a name="General1">General overview</a></h3>
2460
2461<p>The module <code><a
2462href="http://xmlsoft.org/html/libxml-xmlio.html">xmlIO.h</a></code> provides
2463the interfaces to the libxml I/O system. This consists of 4 main parts:</p>
2464<ul>
2465 <li>Entities loader, this is a routine which tries to fetch the entities
2466 (files) based on their PUBLIC and SYSTEM identifiers. The default loader
2467 don't look at the public identifier since libxml do not maintain a
2468 catalog. You can redefine you own entity loader by using
2469 <code>xmlGetExternalEntityLoader()</code> and
Daniel Veillard9c466822001-10-25 12:03:39 +0000[diff] [blame]2470 <code>xmlSetExternalEntityLoader()</code>. <a href="#entities">Check the
2471 example</a>.</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2472 <li>Input I/O buffers which are a commodity structure used by the parser(s)
2473 input layer to handle fetching the informations to feed the parser. This
2474 provides buffering and is also a placeholder where the encoding
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]2475 converters to UTF8 are piggy-backed.</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2476 <li>Output I/O buffers are similar to the Input ones and fulfill similar
2477 task but when generating a serialization from a tree.</li>
2478 <li>A mechanism to register sets of I/O callbacks and associate them with
2479 specific naming schemes like the protocol part of the URIs.
2480 <p>This affect the default I/O operations and allows to use specific I/O
2481 handlers for certain names.</p>
2482 </li>
2483</ul>
2484
2485<p>The general mechanism used when loading http://rpmfind.net/xml.html for
2486example in the HTML parser is the following:</p>
2487<ol>
2488 <li>The default entity loader calls <code>xmlNewInputFromFile()</code> with
2489 the parsing context and the URI string.</li>
2490 <li>the URI string is checked against the existing registered handlers
2491 using their match() callback function, if the HTTP module was compiled
2492 in, it is registered and its match() function will succeeds</li>
2493 <li>the open() function of the handler is called and if successful will
2494 return an I/O Input buffer</li>
2495 <li>the parser will the start reading from this buffer and progressively
2496 fetch information from the resource, calling the read() function of the
2497 handler until the resource is exhausted</li>
2498 <li>if an encoding change is detected it will be installed on the input
2499 buffer, providing buffering and efficient use of the conversion
2500 routines</li>
2501 <li>once the parser has finished, the close() function of the handler is
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]2502 called once and the Input buffer and associated resources are
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2503 deallocated.</li>
2504</ol>
2505
2506<p>The user defined callbacks are checked first to allow overriding of the
2507default libxml I/O routines.</p>
2508
2509<h3><a name="basic">The basic buffer type</a></h3>
2510
2511<p>All the buffer manipulation handling is done using the
2512<code>xmlBuffer</code> type define in <code><a
2513href="http://xmlsoft.org/html/libxml-tree.html">tree.h</a> </code>which is a
2514resizable memory buffer. The buffer allocation strategy can be selected to be
2515either best-fit or use an exponential doubling one (CPU vs. memory use
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]2516trade-off). The values are <code>XML_BUFFER_ALLOC_EXACT</code> and
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2517<code>XML_BUFFER_ALLOC_DOUBLEIT</code>, and can be set individually or on a
2518system wide basis using <code>xmlBufferSetAllocationScheme()</code>. A number
2519of functions allows to manipulate buffers with names starting with the
2520<code>xmlBuffer...</code> prefix.</p>
2521
2522<h3><a name="Input">Input I/O handlers</a></h3>
2523
2524<p>An Input I/O handler is a simple structure
2525<code>xmlParserInputBuffer</code> containing a context associated to the
2526resource (file descriptor, or pointer to a protocol handler), the read() and
2527close() callbacks to use and an xmlBuffer. And extra xmlBuffer and a charset
2528encoding handler are also present to support charset conversion when
2529needed.</p>
2530
2531<h3><a name="Output">Output I/O handlers</a></h3>
2532
2533<p>An Output handler <code>xmlOutputBuffer</code> is completely similar to an
2534Input one except the callbacks are write() and close().</p>
2535
2536<h3><a name="entities">The entities loader</a></h3>
2537
2538<p>The entity loader resolves requests for new entities and create inputs for
2539the parser. Creating an input from a filename or an URI string is done
2540through the xmlNewInputFromFile() routine. The default entity loader do not
2541handle the PUBLIC identifier associated with an entity (if any). So it just
2542calls xmlNewInputFromFile() with the SYSTEM identifier (which is mandatory in
2543XML).</p>
2544
2545<p>If you want to hook up a catalog mechanism then you simply need to
2546override the default entity loader, here is an example:</p>
2547<pre>#include &lt;libxml/xmlIO.h&gt;
2548
2549xmlExternalEntityLoader defaultLoader = NULL;
2550
2551xmlParserInputPtr
2552xmlMyExternalEntityLoader(const char *URL, const char *ID,
2553 xmlParserCtxtPtr ctxt) {
2554 xmlParserInputPtr ret;
2555 const char *fileID = NULL;
2556 /* lookup for the fileID depending on ID */
2557
2558 ret = xmlNewInputFromFile(ctxt, fileID);
2559 if (ret != NULL)
2560 return(ret);
2561 if (defaultLoader != NULL)
2562 ret = defaultLoader(URL, ID, ctxt);
2563 return(ret);
2564}
2565
2566int main(..) {
2567 ...
2568
2569 /*
2570 * Install our own entity loader
2571 */
2572 defaultLoader = xmlGetExternalEntityLoader();
2573 xmlSetExternalEntityLoader(xmlMyExternalEntityLoader);
2574
2575 ...
2576}</pre>
2577
2578<h3><a name="Example2">Example of customized I/O</a></h3>
2579
2580<p>This example come from <a href="http://xmlsoft.org/messages/0708.html">a
2581real use case</a>, xmlDocDump() closes the FILE * passed by the application
2582and this was a problem. The <a
2583href="http://xmlsoft.org/messages/0711.html">solution</a> was to redefine a
2584new output handler with the closing call deactivated:</p>
2585<ol>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]2586 <li>First define a new I/O output allocator where the output don't close the
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2587 file:
2588 <pre>xmlOutputBufferPtr
2589xmlOutputBufferCreateOwn(FILE *file, xmlCharEncodingHandlerPtr encoder) {
2590    xmlOutputBufferPtr ret;
2591    
2592    if (xmlOutputCallbackInitialized == 0)
2593        xmlRegisterDefaultOutputCallbacks();
2594
2595    if (file == NULL) return(NULL);
2596    ret = xmlAllocOutputBuffer(encoder);
2597    if (ret != NULL) {
2598        ret-&gt;context = file;
2599        ret-&gt;writecallback = xmlFileWrite;
2600        ret-&gt;closecallback = NULL; /* No close callback */
2601    }
2602    return(ret); <br>
Daniel Veillard1eb24242002-03-18 11:33:03 +0000[diff] [blame]2603
Daniel Veillard34ce8be2002-03-18 19:37:11 +0000[diff] [blame]2604
2605
Daniel Veillard19274092002-03-25 16:48:03 +0000[diff] [blame]2606
Daniel Veillardb2fb8ed2002-04-01 09:33:12 +0000[diff] [blame]2607
Daniel Veillard75794822002-04-11 16:24:32 +0000[diff] [blame]2608
Daniel Veillarda7084cd2002-04-15 17:12:47 +0000[diff] [blame]2609
Daniel Veillard0bfbb422002-04-26 09:21:45 +0000[diff] [blame]2610
Daniel Veillard93d3a472002-04-26 14:04:55 +0000[diff] [blame]2611
Daniel Veillardcf27f7c2002-04-30 07:12:39 +0000[diff] [blame]2612
Daniel Veillarde6d8e202002-05-02 06:11:10 +0000[diff] [blame]2613
Daniel Veillard9b6fd302002-05-13 12:06:47 +0000[diff] [blame]2614
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2615} </pre>
2616 </li>
2617 <li>And then use it to save the document:
2618 <pre>FILE *f;
2619xmlOutputBufferPtr output;
2620xmlDocPtr doc;
2621int res;
2622
2623f = ...
2624doc = ....
2625
2626output = xmlOutputBufferCreateOwn(f, NULL);
2627res = xmlSaveFileTo(output, doc, NULL);
2628 </pre>
2629 </li>
2630</ol>
2631
2632<h2><a name="Catalog">Catalog support</a></h2>
2633
2634<p>Table of Content:</p>
2635<ol>
2636 <li><a href="General2">General overview</a></li>
2637 <li><a href="#definition">The definition</a></li>
2638 <li><a href="#Simple">Using catalogs</a></li>
2639 <li><a href="#Some">Some examples</a></li>
2640 <li><a href="#reference">How to tune catalog usage</a></li>
2641 <li><a href="#validate">How to debug catalog processing</a></li>
2642 <li><a href="#Declaring">How to create and maintain catalogs</a></li>
2643 <li><a href="#implemento">The implementor corner quick review of the
2644 API</a></li>
2645 <li><a href="#Other">Other resources</a></li>
2646</ol>
2647
2648<h3><a name="General2">General overview</a></h3>
2649
2650<p>What is a catalog? Basically it's a lookup mechanism used when an entity
2651(a file or a remote resource) references another entity. The catalog lookup
2652is inserted between the moment the reference is recognized by the software
2653(XML parser, stylesheet processing, or even images referenced for inclusion
2654in a rendering) and the time where loading that resource is actually
2655started.</p>
2656
2657<p>It is basically used for 3 things:</p>
2658<ul>
2659 <li>mapping from "logical" names, the public identifiers and a more
2660 concrete name usable for download (and URI). For example it can associate
2661 the logical name
2662 <p>"-//OASIS//DTD DocBook XML V4.1.2//EN"</p>
2663 <p>of the DocBook 4.1.2 XML DTD with the actual URL where it can be
2664 downloaded</p>
2665 <p>http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd</p>
2666 </li>
2667 <li>remapping from a given URL to another one, like an HTTP indirection
2668 saying that
2669 <p>"http://www.oasis-open.org/committes/tr.xsl"</p>
2670 <p>should really be looked at</p>
2671 <p>"http://www.oasis-open.org/committes/entity/stylesheets/base/tr.xsl"</p>
2672 </li>
2673 <li>providing a local cache mechanism allowing to load the entities
2674 associated to public identifiers or remote resources, this is a really
2675 important feature for any significant deployment of XML or SGML since it
2676 allows to avoid the aleas and delays associated to fetching remote
2677 resources.</li>
2678</ul>
2679
2680<h3><a name="definition">The definitions</a></h3>
2681
2682<p>Libxml, as of 2.4.3 implements 2 kind of catalogs:</p>
2683<ul>
2684 <li>the older SGML catalogs, the official spec is SGML Open Technical
2685 Resolution TR9401:1997, but is better understood by reading <a
2686 href="http://www.jclark.com/sp/catalog.htm">the SP Catalog page</a> from
2687 James Clark. This is relatively old and not the preferred mode of
2688 operation of libxml.</li>
2689 <li><a href="http://www.oasis-open.org/committees/entity/spec.html">XML
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]2690 Catalogs</a> is far more flexible, more recent, uses an XML syntax and
2691 should scale quite better. This is the default option of libxml.</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2692</ul>
2693
2694<p></p>
2695
2696<h3><a name="Simple">Using catalog</a></h3>
2697
2698<p>In a normal environment libxml will by default check the presence of a
2699catalog in /etc/xml/catalog, and assuming it has been correctly populated,
2700the processing is completely transparent to the document user. To take a
2701concrete example, suppose you are authoring a DocBook document, this one
2702starts with the following DOCTYPE definition:</p>
2703<pre>&lt;?xml version='1.0'?&gt;
2704&lt;!DOCTYPE book PUBLIC "-//Norman Walsh//DTD DocBk XML V3.1.4//EN"
2705 "http://nwalsh.com/docbook/xml/3.1.4/db3xml.dtd"&gt;</pre>
2706
2707<p>When validating the document with libxml, the catalog will be
2708automatically consulted to lookup the public identifier "-//Norman Walsh//DTD
2709DocBk XML V3.1.4//EN" and the system identifier
2710"http://nwalsh.com/docbook/xml/3.1.4/db3xml.dtd", and if these entities have
2711been installed on your system and the catalogs actually point to them, libxml
2712will fetch them from the local disk.</p>
2713
2714<p style="font-size: 10pt"><strong>Note</strong>: Really don't use this
2715DOCTYPE example it's a really old version, but is fine as an example.</p>
2716
2717<p>Libxml will check the catalog each time that it is requested to load an
2718entity, this includes DTD, external parsed entities, stylesheets, etc ... If
2719your system is correctly configured all the authoring phase and processing
2720should use only local files, even if your document stays portable because it
2721uses the canonical public and system ID, referencing the remote document.</p>
2722
2723<h3><a name="Some">Some examples:</a></h3>
2724
2725<p>Here is a couple of fragments from XML Catalogs used in libxml early
2726regression tests in <code>test/catalogs</code> :</p>
2727<pre>&lt;?xml version="1.0"?&gt;
2728&lt;!DOCTYPE catalog PUBLIC
2729 "-//OASIS//DTD Entity Resolution XML Catalog V1.0//EN"
2730 "http://www.oasis-open.org/committees/entity/release/1.0/catalog.dtd"&gt;
2731&lt;catalog xmlns="urn:oasis:names:tc:entity:xmlns:xml:catalog"&gt;
2732 &lt;public publicId="-//OASIS//DTD DocBook XML V4.1.2//EN"
2733 uri="http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd"/&gt;
2734...</pre>
2735
2736<p>This is the beginning of a catalog for DocBook 4.1.2, XML Catalogs are
2737written in XML, there is a specific namespace for catalog elements
2738"urn:oasis:names:tc:entity:xmlns:xml:catalog". The first entry in this
2739catalog is a <code>public</code> mapping it allows to associate a Public
2740Identifier with an URI.</p>
2741<pre>...
2742 &lt;rewriteSystem systemIdStartString="http://www.oasis-open.org/docbook/"
2743 rewritePrefix="file:///usr/share/xml/docbook/"/&gt;
2744...</pre>
2745
2746<p>A <code>rewriteSystem</code> is a very powerful instruction, it says that
2747any URI starting with a given prefix should be looked at another URI
2748constructed by replacing the prefix with an new one. In effect this acts like
2749a cache system for a full area of the Web. In practice it is extremely useful
2750with a file prefix if you have installed a copy of those resources on your
2751local system.</p>
2752<pre>...
2753&lt;delegatePublic publicIdStartString="-//OASIS//DTD XML Catalog //"
2754 catalog="file:///usr/share/xml/docbook.xml"/&gt;
2755&lt;delegatePublic publicIdStartString="-//OASIS//ENTITIES DocBook XML"
2756 catalog="file:///usr/share/xml/docbook.xml"/&gt;
2757&lt;delegatePublic publicIdStartString="-//OASIS//DTD DocBook XML"
2758 catalog="file:///usr/share/xml/docbook.xml"/&gt;
2759&lt;delegateSystem systemIdStartString="http://www.oasis-open.org/docbook/"
2760 catalog="file:///usr/share/xml/docbook.xml"/&gt;
2761&lt;delegateURI uriStartString="http://www.oasis-open.org/docbook/"
2762 catalog="file:///usr/share/xml/docbook.xml"/&gt;
2763...</pre>
2764
2765<p>Delegation is the core features which allows to build a tree of catalogs,
2766easier to maintain than a single catalog, based on Public Identifier, System
2767Identifier or URI prefixes it instructs the catalog software to look up
2768entries in another resource. This feature allow to build hierarchies of
2769catalogs, the set of entries presented should be sufficient to redirect the
2770resolution of all DocBook references to the specific catalog in
2771<code>/usr/share/xml/docbook.xml</code> this one in turn could delegate all
2772references for DocBook 4.2.1 to a specific catalog installed at the same time
2773as the DocBook resources on the local machine.</p>
2774
2775<h3><a name="reference">How to tune catalog usage:</a></h3>
2776
2777<p>The user can change the default catalog behaviour by redirecting queries
2778to its own set of catalogs, this can be done by setting the
2779<code>XML_CATALOG_FILES</code> environment variable to a list of catalogs, an
2780empty one should deactivate loading the default <code>/etc/xml/catalog</code>
2781default catalog</p>
2782
2783<h3><a name="validate">How to debug catalog processing:</a></h3>
2784
2785<p>Setting up the <code>XML_DEBUG_CATALOG</code> environment variable will
2786make libxml output debugging informations for each catalog operations, for
2787example:</p>
2788<pre>orchis:~/XML -&gt; xmllint --memory --noout test/ent2
2789warning: failed to load external entity "title.xml"
2790orchis:~/XML -&gt; export XML_DEBUG_CATALOG=
2791orchis:~/XML -&gt; xmllint --memory --noout test/ent2
2792Failed to parse catalog /etc/xml/catalog
2793Failed to parse catalog /etc/xml/catalog
2794warning: failed to load external entity "title.xml"
2795Catalogs cleanup
2796orchis:~/XML -&gt; </pre>
2797
2798<p>The test/ent2 references an entity, running the parser from memory makes
2799the base URI unavailable and the the "title.xml" entity cannot be loaded.
2800Setting up the debug environment variable allows to detect that an attempt is
2801made to load the <code>/etc/xml/catalog</code> but since it's not present the
2802resolution fails.</p>
2803
2804<p>But the most advanced way to debug XML catalog processing is to use the
2805<strong>xmlcatalog</strong> command shipped with libxml2, it allows to load
2806catalogs and make resolution queries to see what is going on. This is also
2807used for the regression tests:</p>
2808<pre>orchis:~/XML -&gt; ./xmlcatalog test/catalogs/docbook.xml \
2809 "-//OASIS//DTD DocBook XML V4.1.2//EN"
2810http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd
2811orchis:~/XML -&gt; </pre>
2812
2813<p>For debugging what is going on, adding one -v flags increase the verbosity
2814level to indicate the processing done (adding a second flag also indicate
2815what elements are recognized at parsing):</p>
2816<pre>orchis:~/XML -&gt; ./xmlcatalog -v test/catalogs/docbook.xml \
2817 "-//OASIS//DTD DocBook XML V4.1.2//EN"
2818Parsing catalog test/catalogs/docbook.xml's content
2819Found public match -//OASIS//DTD DocBook XML V4.1.2//EN
2820http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd
2821Catalogs cleanup
2822orchis:~/XML -&gt; </pre>
2823
2824<p>A shell interface is also available to debug and process multiple queries
2825(and for regression tests):</p>
2826<pre>orchis:~/XML -&gt; ./xmlcatalog -shell test/catalogs/docbook.xml \
2827 "-//OASIS//DTD DocBook XML V4.1.2//EN"
2828&gt; help
2829Commands available:
2830public PublicID: make a PUBLIC identifier lookup
2831system SystemID: make a SYSTEM identifier lookup
2832resolve PublicID SystemID: do a full resolver lookup
2833add 'type' 'orig' 'replace' : add an entry
2834del 'values' : remove values
2835dump: print the current catalog state
2836debug: increase the verbosity level
2837quiet: decrease the verbosity level
2838exit: quit the shell
2839&gt; public "-//OASIS//DTD DocBook XML V4.1.2//EN"
2840http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd
2841&gt; quit
2842orchis:~/XML -&gt; </pre>
2843
2844<p>This should be sufficient for most debugging purpose, this was actually
2845used heavily to debug the XML Catalog implementation itself.</p>
2846
2847<h3><a name="Declaring">How to create and maintain</a> catalogs:</h3>
2848
2849<p>Basically XML Catalogs are XML files, you can either use XML tools to
2850manage them or use <strong>xmlcatalog</strong> for this. The basic step is
2851to create a catalog the -create option provide this facility:</p>
2852<pre>orchis:~/XML -&gt; ./xmlcatalog --create tst.xml
2853&lt;?xml version="1.0"?&gt;
2854&lt;!DOCTYPE catalog PUBLIC "-//OASIS//DTD Entity Resolution XML Catalog V1.0//EN"
2855 "http://www.oasis-open.org/committees/entity/release/1.0/catalog.dtd"&gt;
2856&lt;catalog xmlns="urn:oasis:names:tc:entity:xmlns:xml:catalog"/&gt;
2857orchis:~/XML -&gt; </pre>
2858
2859<p>By default xmlcatalog does not overwrite the original catalog and save the
2860result on the standard output, this can be overridden using the -noout
2861option. The <code>-add</code> command allows to add entries in the
2862catalog:</p>
2863<pre>orchis:~/XML -&gt; ./xmlcatalog --noout --create --add "public" \
2864 "-//OASIS//DTD DocBook XML V4.1.2//EN" \
2865 http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd tst.xml
2866orchis:~/XML -&gt; cat tst.xml
2867&lt;?xml version="1.0"?&gt;
2868&lt;!DOCTYPE catalog PUBLIC "-//OASIS//DTD Entity Resolution XML Catalog V1.0//EN" \
2869 "http://www.oasis-open.org/committees/entity/release/1.0/catalog.dtd"&gt;
2870&lt;catalog xmlns="urn:oasis:names:tc:entity:xmlns:xml:catalog"&gt;
2871&lt;public publicId="-//OASIS//DTD DocBook XML V4.1.2//EN"
2872 uri="http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd"/&gt;
2873&lt;/catalog&gt;
2874orchis:~/XML -&gt; </pre>
2875
2876<p>The <code>-add</code> option will always take 3 parameters even if some of
2877the XML Catalog constructs (like nextCatalog) will have only a single
2878argument, just pass a third empty string, it will be ignored.</p>
2879
2880<p>Similarly the <code>-del</code> option remove matching entries from the
2881catalog:</p>
2882<pre>orchis:~/XML -&gt; ./xmlcatalog --del \
2883 "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd" tst.xml
2884&lt;?xml version="1.0"?&gt;
2885&lt;!DOCTYPE catalog PUBLIC "-//OASIS//DTD Entity Resolution XML Catalog V1.0//EN"
2886 "http://www.oasis-open.org/committees/entity/release/1.0/catalog.dtd"&gt;
2887&lt;catalog xmlns="urn:oasis:names:tc:entity:xmlns:xml:catalog"/&gt;
2888orchis:~/XML -&gt; </pre>
2889
2890<p>The catalog is now empty. Note that the matching of <code>-del</code> is
2891exact and would have worked in a similar fashion with the Public ID
2892string.</p>
2893
2894<p>This is rudimentary but should be sufficient to manage a not too complex
2895catalog tree of resources.</p>
2896
2897<h3><a name="implemento">The implementor corner quick review of the
2898API:</a></h3>
2899
2900<p>First, and like for every other module of libxml, there is an
2901automatically generated <a href="html/libxml-catalog.html">API page for
2902catalog support</a>.</p>
2903
2904<p>The header for the catalog interfaces should be included as:</p>
2905<pre>#include &lt;libxml/catalog.h&gt;</pre>
2906
2907<p>The API is voluntarily kept very simple. First it is not obvious that
2908applications really need access to it since it is the default behaviour of
2909libxml (Note: it is possible to completely override libxml default catalog by
2910using <a href="html/libxml-parser.html">xmlSetExternalEntityLoader</a> to
2911plug an application specific resolver).</p>
2912
2913<p>Basically libxml support 2 catalog lists:</p>
2914<ul>
2915 <li>the default one, global shared by all the application</li>
2916 <li>a per-document catalog, this one is built if the document uses the
2917 <code>oasis-xml-catalog</code> PIs to specify its own catalog list, it is
2918 associated to the parser context and destroyed when the parsing context
2919 is destroyed.</li>
2920</ul>
2921
2922<p>the document one will be used first if it exists.</p>
2923
2924<h4>Initialization routines:</h4>
2925
2926<p>xmlInitializeCatalog(), xmlLoadCatalog() and xmlLoadCatalogs() should be
2927used at startup to initialize the catalog, if the catalog should be
2928initialized with specific values xmlLoadCatalog() or xmlLoadCatalogs()
2929should be called before xmlInitializeCatalog() which would otherwise do a
2930default initialization first.</p>
2931
2932<p>The xmlCatalogAddLocal() call is used by the parser to grow the document
2933own catalog list if needed.</p>
2934
2935<h4>Preferences setup:</h4>
2936
2937<p>The XML Catalog spec requires the possibility to select default
2938preferences between public and system delegation,
2939xmlCatalogSetDefaultPrefer() allows this, xmlCatalogSetDefaults() and
2940xmlCatalogGetDefaults() allow to control if XML Catalogs resolution should
2941be forbidden, allowed for global catalog, for document catalog or both, the
2942default is to allow both.</p>
2943
2944<p>And of course xmlCatalogSetDebug() allows to generate debug messages
2945(through the xmlGenericError() mechanism).</p>
2946
2947<h4>Querying routines:</h4>
2948
2949<p>xmlCatalogResolve(), xmlCatalogResolveSystem(), xmlCatalogResolvePublic()
2950and xmlCatalogResolveURI() are relatively explicit if you read the XML
2951Catalog specification they correspond to section 7 algorithms, they should
2952also work if you have loaded an SGML catalog with a simplified semantic.</p>
2953
2954<p>xmlCatalogLocalResolve() and xmlCatalogLocalResolveURI() are the same but
2955operate on the document catalog list</p>
2956
2957<h4>Cleanup and Miscellaneous:</h4>
2958
2959<p>xmlCatalogCleanup() free-up the global catalog, xmlCatalogFreeLocal() is
2960the per-document equivalent.</p>
2961
2962<p>xmlCatalogAdd() and xmlCatalogRemove() are used to dynamically modify the
2963first catalog in the global list, and xmlCatalogDump() allows to dump a
2964catalog state, those routines are primarily designed for xmlcatalog, I'm not
2965sure that exposing more complex interfaces (like navigation ones) would be
2966really useful.</p>
2967
2968<p>The xmlParseCatalogFile() is a function used to load XML Catalog files,
2969it's similar as xmlParseFile() except it bypass all catalog lookups, it's
2970provided because this functionality may be useful for client tools.</p>
2971
2972<h4>threaded environments:</h4>
2973
2974<p>Since the catalog tree is built progressively, some care has been taken to
2975try to avoid troubles in multithreaded environments. The code is now thread
2976safe assuming that the libxml library has been compiled with threads
2977support.</p>
2978
2979<p></p>
2980
2981<h3><a name="Other">Other resources</a></h3>
2982
2983<p>The XML Catalog specification is relatively recent so there isn't much
2984literature to point at:</p>
2985<ul>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]2986 <li>You can find a good rant from Norm Walsh about <a
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2987 href="http://www.arbortext.com/Think_Tank/XML_Resources/Issue_Three/issue_three.html">the
2988 need for catalogs</a>, it provides a lot of context informations even if
Daniel Veillard93d3a472002-04-26 14:04:55 +0000[diff] [blame]2989 I don't agree with everything presented. Norm also wrote a more recent
2990 article <a
2991 href="http://wwws.sun.com/software/xml/developers/resolver/article/">XML
2992 entities and URI resolvers</a> describing them.</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2993 <li>An <a href="http://home.ccil.org/~cowan/XML/XCatalog.html">old XML
2994 catalog proposal</a> from John Cowan</li>
2995 <li>The <a href="http://www.rddl.org/">Resource Directory Description
2996 Language</a> (RDDL) another catalog system but more oriented toward
2997 providing metadata for XML namespaces.</li>
2998 <li>the page from the OASIS Technical <a
2999 href="http://www.oasis-open.org/committees/entity/">Committee on Entity
3000 Resolution</a> who maintains XML Catalog, you will find pointers to the
3001 specification update, some background and pointers to others tools
3002 providing XML Catalog support</li>
Daniel Veillard35e937a2002-01-19 22:21:54 +0000[diff] [blame]3003 <li>Here is a <a href="buildDocBookCatalog">shell script</a> to generate
3004 XML Catalogs for DocBook 4.1.2 . If it can write to the /etc/xml/
3005 directory, it will set-up /etc/xml/catalog and /etc/xml/docbook based on
3006 the resources found on the system. Otherwise it will just create
3007 ~/xmlcatalog and ~/dbkxmlcatalog and doing:
Daniel Veillardc575b992002-02-08 13:28:40 +0000[diff] [blame]3008 <p><code>export XMLCATALOG=$HOME/xmlcatalog</code></p>
Daniel Veillard35e937a2002-01-19 22:21:54 +0000[diff] [blame]3009 <p>should allow to process DocBook documentations without requiring
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]3010 network accesses for the DTD or stylesheets</p>
Daniel Veillard35e937a2002-01-19 22:21:54 +0000[diff] [blame]3011 </li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3012 <li>I have uploaded <a href="ftp://xmlsoft.org/test/dbk412catalog.tar.gz">a
Daniel Veillard35e937a2002-01-19 22:21:54 +0000[diff] [blame]3013 small tarball</a> containing XML Catalogs for DocBook 4.1.2 which seems
3014 to work fine for me too</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3015 <li>The <a href="http://www.xmlsoft.org/xmlcatalog_man.html">xmlcatalog
3016 manual page</a></li>
3017</ul>
3018
3019<p>If you have suggestions for corrections or additions, simply contact
3020me:</p>
3021
3022<h2><a name="library">The parser interfaces</a></h2>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3023
3024<p>This section is directly intended to help programmers getting bootstrapped
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3025using the XML library from the C language. It is not intended to be
3026extensive. I hope the automatically generated documents will provide the
3027completeness required, but as a separate set of documents. The interfaces of
3028the XML library are by principle low level, there is nearly zero abstraction.
3029Those interested in a higher level API should <a href="#DOM">look at
3030DOM</a>.</p>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]3031
Daniel Veillard9cb5ff42001-01-29 08:22:21 +0000[diff] [blame]3032<p>The <a href="html/libxml-parser.html">parser interfaces for XML</a> are
3033separated from the <a href="html/libxml-htmlparser.html">HTML parser
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3034interfaces</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]3035
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3036<h3><a name="Invoking">Invoking the parser : the pull method</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3037
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3038<p>Usually, the first thing to do is to read an XML input. The parser accepts
3039documents either from in-memory strings or from files. The functions are
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3040defined in "parser.h":</p>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]3041<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3042 <dt><code>xmlDocPtr xmlParseMemory(char *buffer, int size);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3043 <dd><p>Parse a null-terminated string containing the document.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3044 </dd>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]3045</dl>
3046<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3047 <dt><code>xmlDocPtr xmlParseFile(const char *filename);</code></dt>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]3048 <dd><p>Parse an XML document contained in a (possibly compressed)
3049 file.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3050 </dd>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]3051</dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3052
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3053<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]3054failure).</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3055
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3056<h3 id="Invoking1">Invoking the parser: the push method</h3>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]3057
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3058<p>In order for the application to keep the control when the document is
3059being fetched (which is common for GUI based programs) libxml provides a push
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3060interface, too, as of version 1.8.3. Here are the interface functions:</p>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]3061<pre>xmlParserCtxtPtr xmlCreatePushParserCtxt(xmlSAXHandlerPtr sax,
3062 void *user_data,
3063 const char *chunk,
3064 int size,
3065 const char *filename);
3066int xmlParseChunk (xmlParserCtxtPtr ctxt,
3067 const char *chunk,
3068 int size,
3069 int terminate);</pre>
3070
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3071<p>and here is a simple example showing how to use the interface:</p>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]3072<pre> FILE *f;
3073
3074 f = fopen(filename, "r");
3075 if (f != NULL) {
3076 int res, size = 1024;
3077 char chars[1024];
3078 xmlParserCtxtPtr ctxt;
3079
3080 res = fread(chars, 1, 4, f);
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3081 if (res &gt; 0) {
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]3082 ctxt = xmlCreatePushParserCtxt(NULL, NULL,
3083 chars, res, filename);
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3084 while ((res = fread(chars, 1, size, f)) &gt; 0) {
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]3085 xmlParseChunk(ctxt, chars, res, 0);
3086 }
3087 xmlParseChunk(ctxt, chars, 0, 1);
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3088 doc = ctxt-&gt;myDoc;
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]3089 xmlFreeParserCtxt(ctxt);
3090 }
3091 }</pre>
3092
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]3093<p>The HTML parser embedded into libxml also has a push interface; the
3094functions are just prefixed by "html" rather than "xml".</p>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]3095
3096<h3 id="Invoking2">Invoking the parser: the SAX interface</h3>
3097
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]3098<p>The tree-building interface makes the parser memory-hungry, first loading
3099the document in memory and then building the tree itself. Reading a document
3100without building the tree is possible using the SAX interfaces (see SAX.h and
3101<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]3102Henstridge's documentation</a>). Note also that the push interface can be
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3103limited to SAX: just use the two first arguments of
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]3104<code>xmlCreatePushParserCtxt()</code>.</p>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]3105
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]3106<h3><a name="Building">Building a tree from scratch</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3107
3108<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]3109there is a set of functions dedicated to building new elements. (These are
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3110also described in &lt;libxml/tree.h&gt;.) For example, here is a piece of
3111code that produces the XML document used in the previous examples:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3112<pre> #include &lt;libxml/tree.h&gt;
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]3113 xmlDocPtr doc;
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3114 xmlNodePtr tree, subtree;
3115
3116 doc = xmlNewDoc("1.0");
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3117 doc-&gt;children = xmlNewDocNode(doc, NULL, "EXAMPLE", NULL);
3118 xmlSetProp(doc-&gt;children, "prop1", "gnome is great");
3119 xmlSetProp(doc-&gt;children, "prop2", "&amp; linux too");
3120 tree = xmlNewChild(doc-&gt;children, NULL, "head", NULL);
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3121 subtree = xmlNewChild(tree, NULL, "title", "Welcome to Gnome");
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3122 tree = xmlNewChild(doc-&gt;children, NULL, "chapter", NULL);
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3123 subtree = xmlNewChild(tree, NULL, "title", "The Linux adventure");
3124 subtree = xmlNewChild(tree, NULL, "p", "bla bla bla ...");
3125 subtree = xmlNewChild(tree, NULL, "image", NULL);
3126 xmlSetProp(subtree, "href", "linus.gif");</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3127
3128<p>Not really rocket science ...</p>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3129
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]3130<h3><a name="Traversing">Traversing the tree</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3131
Daniel Veillard9cb5ff42001-01-29 08:22:21 +0000[diff] [blame]3132<p>Basically by <a href="html/libxml-tree.html">including "tree.h"</a> your
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3133code has access to the internal structure of all the elements of the tree.
3134The names should be somewhat simple like <strong>parent</strong>,
Daniel Veillard306be992000-07-03 12:38:45 +0000[diff] [blame]3135<strong>children</strong>, <strong>next</strong>, <strong>prev</strong>,
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3136<strong>properties</strong>, etc... For example, still with the previous
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]3137example:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3138<pre><code>doc-&gt;children-&gt;children-&gt;children</code></pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3139
3140<p>points to the title element,</p>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3141<pre>doc-&gt;children-&gt;children-&gt;next-&gt;children-&gt;children</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3142
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]3143<p>points to the text node containing the chapter title "The Linux
3144adventure".</p>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]3145
Daniel Veillardb24054a1999-12-18 15:32:46 +0000[diff] [blame]3146<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]3147present before the document root, so <code>doc-&gt;children</code> may point
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3148to an element which is not the document Root Element; a function
Daniel Veillard5cb5ab81999-12-21 15:35:29 +0000[diff] [blame]3149<code>xmlDocGetRootElement()</code> was added for this purpose.</p>
Daniel Veillardb24054a1999-12-18 15:32:46 +0000[diff] [blame]3150
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]3151<h3><a name="Modifying">Modifying the tree</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3152
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3153<p>Functions are provided for reading and writing the document content. Here
Daniel Veillard9cb5ff42001-01-29 08:22:21 +0000[diff] [blame]3154is an excerpt from the <a href="html/libxml-tree.html">tree API</a>:</p>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3155<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +0000[diff] [blame]3156 <dt><code>xmlAttrPtr xmlSetProp(xmlNodePtr node, const xmlChar *name, const
3157 xmlChar *value);</code></dt>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3158 <dd><p>This sets (or changes) an attribute carried by an ELEMENT node.
3159 The value can be NULL.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3160 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3161</dl>
3162<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +0000[diff] [blame]3163 <dt><code>const xmlChar *xmlGetProp(xmlNodePtr node, const xmlChar
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3164 *name);</code></dt>
Daniel Veillardc92c3042000-09-29 02:42:04 +0000[diff] [blame]3165 <dd><p>This function returns a pointer to new copy of the property
3166 content. Note that the user must deallocate the result.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3167 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3168</dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3169
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3170<p>Two functions are provided for reading and writing the text associated
3171with elements:</p>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3172<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +0000[diff] [blame]3173 <dt><code>xmlNodePtr xmlStringGetNodeList(xmlDocPtr doc, const xmlChar
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3174 *value);</code></dt>
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]3175 <dd><p>This function takes an "external" string and converts it to one
3176 text node or possibly to a list of entity and text nodes. All
3177 non-predefined entity references like &amp;Gnome; will be stored
3178 internally as entity nodes, hence the result of the function may not be
3179 a single node.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3180 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3181</dl>
3182<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +0000[diff] [blame]3183 <dt><code>xmlChar *xmlNodeListGetString(xmlDocPtr doc, xmlNodePtr list, int
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3184 inLine);</code></dt>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]3185 <dd><p>This function is the inverse of
3186 <code>xmlStringGetNodeList()</code>. It generates a new string
3187 containing the content of the text and entity nodes. Note the extra
3188 argument inLine. If this argument is set to 1, the function will expand
3189 entity references. For example, instead of returning the &amp;Gnome;
3190 XML encoding in the string, it will substitute it with its value (say,
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3191 "GNU Network Object Model Environment").</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>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]3194
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]3195<h3><a name="Saving">Saving a tree</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3196
3197<p>Basically 3 options are possible:</p>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3198<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +0000[diff] [blame]3199 <dt><code>void xmlDocDumpMemory(xmlDocPtr cur, xmlChar**mem, int
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3200 *size);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3201 <dd><p>Returns a buffer into which the document has been saved.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3202 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3203</dl>
3204<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3205 <dt><code>extern void xmlDocDump(FILE *f, xmlDocPtr doc);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3206 <dd><p>Dumps a document to an open file descriptor.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3207 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3208</dl>
3209<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3210 <dt><code>int xmlSaveFile(const char *filename, xmlDocPtr cur);</code></dt>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]3211 <dd><p>Saves the document to a file. In this case, the compression
3212 interface is triggered if it has been turned on.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3213 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3214</dl>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]3215
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]3216<h3><a name="Compressio">Compression</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3217
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3218<p>The library transparently handles compression when doing file-based
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]3219accesses. The level of compression on saves can be turned on either globally
3220or individually for one file:</p>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3221<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3222 <dt><code>int xmlGetDocCompressMode (xmlDocPtr doc);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3223 <dd><p>Gets the document compression ratio (0-9).</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3224 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3225</dl>
3226<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3227 <dt><code>void xmlSetDocCompressMode (xmlDocPtr doc, int mode);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3228 <dd><p>Sets the document compression ratio.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3229 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3230</dl>
3231<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3232 <dt><code>int xmlGetCompressMode(void);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3233 <dd><p>Gets the default compression ratio.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3234 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3235</dl>
3236<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3237 <dt><code>void xmlSetCompressMode(int mode);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3238 <dd><p>Sets the default compression ratio.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3239 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3240</dl>
3241
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]3242<h2><a name="Entities">Entities or no entities</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3243
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3244<p>Entities in principle are similar to simple C macros. An entity defines an
3245abbreviation for a given string that you can reuse many times throughout the
3246content of your document. Entities are especially useful when a given string
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]3247may occur frequently within a document, or to confine the change needed to a
3248document to a restricted area in the internal subset of the document (at the
3249beginning). Example:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3250<pre>1 &lt;?xml version="1.0"?&gt;
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]32512 &lt;!DOCTYPE EXAMPLE SYSTEM "example.dtd" [
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]32523 &lt;!ENTITY xml "Extensible Markup Language"&gt;
32534 ]&gt;
32545 &lt;EXAMPLE&gt;
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]32556 &amp;xml;
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]32567 &lt;/EXAMPLE&gt;</pre>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3257
3258<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]3259its name with '&amp;' and following it by ';' without any spaces added. There
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]3260are 5 predefined entities in libxml allowing you to escape characters with
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3261predefined meaning in some parts of the xml document content:
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3262<strong>&amp;lt;</strong> for the character '&lt;', <strong>&amp;gt;</strong>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3263for the character '&gt;', <strong>&amp;apos;</strong> for the character ''',
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3264<strong>&amp;quot;</strong> for the character '"', and
3265<strong>&amp;amp;</strong> for the character '&amp;'.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3266
3267<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]3268substitute an entity's content so that you can see the replacement text in
3269your application. Or you may prefer to keep entity references as such in the
3270content to be able to save the document back without losing this usually
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3271precious information (if the user went through the pain of explicitly
3272defining entities, he may have a a rather negative attitude if you blindly
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]3273substitute them as saving time). The <a
Daniel Veillard9cb5ff42001-01-29 08:22:21 +0000[diff] [blame]3274href="html/libxml-parser.html#XMLSUBSTITUTEENTITIESDEFAULT">xmlSubstituteEntitiesDefault()</a>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3275function allows you to check and change the behaviour, which is to not
3276substitute entities by default.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3277
3278<p>Here is the DOM tree built by libxml for the previous document in the
3279default case:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3280<pre>/gnome/src/gnome-xml -&gt; ./xmllint --debug test/ent1
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3281DOCUMENT
3282version=1.0
3283 ELEMENT EXAMPLE
3284 TEXT
3285 content=
3286 ENTITY_REF
3287 INTERNAL_GENERAL_ENTITY xml
3288 content=Extensible Markup Language
3289 TEXT
3290 content=</pre>
3291
3292<p>And here is the result when substituting entities:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3293<pre>/gnome/src/gnome-xml -&gt; ./tester --debug --noent test/ent1
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3294DOCUMENT
3295version=1.0
3296 ELEMENT EXAMPLE
3297 TEXT
3298 content= Extensible Markup Language</pre>
3299
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3300<p>So, entities or no entities? Basically, it depends on your use case. I
3301suggest that you keep the non-substituting default behaviour and avoid using
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3302entities in your XML document or data if you are not willing to handle the
3303entity references elements in the DOM tree.</p>
3304
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3305<p>Note that at save time libxml enforces the conversion of the predefined
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3306entities where necessary to prevent well-formedness problems, and will also
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3307transparently replace those with chars (i.e. it will not generate entity
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3308reference elements in the DOM tree or call the reference() SAX callback when
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3309finding them in the input).</p>
3310
Daniel Veillard7b9c4b72000-08-25 16:26:50 +0000[diff] [blame]3311<p><span style="background-color: #FF0000">WARNING</span>: handling entities
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3312on top of the libxml SAX interface is difficult!!! If you plan to use
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]3313non-predefined entities in your documents, then the learning curve to handle
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3314then 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]3315strongly suggest you consider using the DOM interface instead and let libxml
Daniel Veillard8c6d6af2000-08-25 17:14:13 +0000[diff] [blame]3316deal with the complexity rather than trying to do it yourself.</p>
Daniel Veillard7b9c4b72000-08-25 16:26:50 +0000[diff] [blame]3317
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]3318<h2><a name="Namespaces">Namespaces</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3319
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]3320<p>The libxml library implements <a
3321href="http://www.w3.org/TR/REC-xml-names/">XML namespaces</a> support by
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]3322recognizing namespace constructs in the input, and does namespace lookup
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]3323automatically when building the DOM tree. A namespace declaration is
3324associated with an in-memory structure and all elements or attributes within
3325that namespace point to it. Hence testing the namespace is a simple and fast
3326equality operation at the user level.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3327
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]3328<p>I suggest that people using libxml use a namespace, and declare it in the
3329root element of their document as the default namespace. Then they don't need
3330to 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]3331refinement and merging of data from different sources. This doesn't increase
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]3332the size of the XML output significantly, but significantly increases its
3333value in the long-term. Example:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3334<pre>&lt;mydoc xmlns="http://mydoc.example.org/schemas/"&gt;
3335 &lt;elem1&gt;...&lt;/elem1&gt;
3336 &lt;elem2&gt;...&lt;/elem2&gt;
3337&lt;/mydoc&gt;</pre>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3338
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]3339<p>The namespace value has to be an absolute URL, but the URL doesn't have to
3340point to any existing resource on the Web. It will bind all the element and
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]3341attributes with that URL. I suggest to use an URL within a domain you control,
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]3342and that the URL should contain some kind of version information if possible.
3343For example, <code>"http://www.gnome.org/gnumeric/1.0/"</code> is a good
3344namespace scheme.</p>
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]3345
3346<p>Then when you load a file, make sure that a namespace carrying the
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3347version-independent prefix is installed on the root element of your document,
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3348and if the version information don't match something you know, warn the user
3349and 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]3350namespace checking on the prefix value. &lt;foo:text&gt; may be exactly the
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3351same as &lt;bar:text&gt; in another document. What really matters is the URI
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3352associated with the element or the attribute, not the prefix string (which is
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3353just a shortcut for the full URI). In libxml, element and attributes have an
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]3354<code>ns</code> field pointing to an xmlNs structure detailing the namespace
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3355prefix and its URI.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3356
3357<p>@@Interfaces@@</p>
3358
3359<p>@@Examples@@</p>
3360
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3361<p>Usually people object to using namespaces together with validity checking.
3362I will try to make sure that using namespaces won't break validity checking,
3363so even if you plan to use or currently are using validation I strongly
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]3364suggest adding namespaces to your document. A default namespace scheme
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3365<code>xmlns="http://...."</code> should not break validity even on less
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3366flexible parsers. Using namespaces to mix and differentiate content coming
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3367from multiple DTDs will certainly break current validation schemes. I will
3368try to provide ways to do this, but this may not be portable or
3369standardized.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3370
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3371<h2><a name="Upgrading">Upgrading 1.x code</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3372
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3373<p>Incompatible changes:</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3374
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3375<p>Version 2 of libxml is the first version introducing serious backward
3376incompatible changes. The main goals were:</p>
3377<ul>
3378 <li>a general cleanup. A number of mistakes inherited from the very early
3379 versions couldn't be changed due to compatibility constraints. Example
3380 the "childs" element in the nodes.</li>
3381 <li>Uniformization of the various nodes, at least for their header and link
3382 parts (doc, parent, children, prev, next), the goal is a simpler
3383 programming model and simplifying the task of the DOM implementors.</li>
3384 <li>better conformances to the XML specification, for example version 1.x
3385 had an heuristic to try to detect ignorable white spaces. As a result the
3386 SAX event generated were ignorableWhitespace() while the spec requires
3387 character() in that case. This also mean that a number of DOM node
3388 containing blank text may populate the DOM tree which were not present
3389 before.</li>
3390</ul>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3391
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3392<h3>How to fix libxml-1.x code:</h3>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3393
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3394<p>So client code of libxml designed to run with version 1.x may have to be
3395changed to compile against version 2.x of libxml. Here is a list of changes
3396that I have collected, they may not be sufficient, so in case you find other
3397change which are required, <a href="mailto:Daniel.Ïeillardw3.org">drop me a
3398mail</a>:</p>
3399<ol>
3400 <li>The package name have changed from libxml to libxml2, the library name
3401 is now -lxml2 . There is a new xml2-config script which should be used to
3402 select the right parameters libxml2</li>
3403 <li>Node <strong>childs</strong> field has been renamed
3404 <strong>children</strong> so s/childs/children/g should be applied
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]3405 (probability of having "childs" anywhere else is close to 0+</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3406 <li>The document don't have anymore a <strong>root</strong> element it has
3407 been replaced by <strong>children</strong> and usually you will get a
3408 list of element here. For example a Dtd element for the internal subset
3409 and it's declaration may be found in that list, as well as processing
3410 instructions or comments found before or after the document root element.
3411 Use <strong>xmlDocGetRootElement(doc)</strong> to get the root element of
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]3412 a document. Alternatively if you are sure to not reference DTDs nor have
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3413 PIs or comments before or after the root element
3414 s/-&gt;root/-&gt;children/g will probably do it.</li>
3415 <li>The white space issue, this one is more complex, unless special case of
3416 validating parsing, the line breaks and spaces usually used for indenting
3417 and formatting the document content becomes significant. So they are
3418 reported by SAX and if your using the DOM tree, corresponding nodes are
3419 generated. Too approach can be taken:
3420 <ol>
3421 <li>lazy one, use the compatibility call
3422 <strong>xmlKeepBlanksDefault(0)</strong> but be aware that you are
3423 relying on a special (and possibly broken) set of heuristics of
3424 libxml to detect ignorable blanks. Don't complain if it breaks or
3425 make your application not 100% clean w.r.t. to it's input.</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]3426 <li>the Right Way: change you code to accept possibly insignificant
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3427 blanks characters, or have your tree populated with weird blank text
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]3428 nodes. You can spot them using the commodity function
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3429 <strong>xmlIsBlankNode(node)</strong> returning 1 for such blank
3430 nodes.</li>
3431 </ol>
3432 <p>Note also that with the new default the output functions don't add any
3433 extra indentation when saving a tree in order to be able to round trip
3434 (read and save) without inflating the document with extra formatting
3435 chars.</p>
3436 </li>
3437 <li>The include path has changed to $prefix/libxml/ and the includes
3438 themselves uses this new prefix in includes instructions... If you are
3439 using (as expected) the
3440 <pre>xml2-config --cflags</pre>
3441 <p>output to generate you compile commands this will probably work out of
3442 the box</p>
3443 </li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]3444 <li>xmlDetectCharEncoding takes an extra argument indicating the length in
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3445 byte of the head of the document available for character detection.</li>
3446</ol>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3447
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3448<h3>Ensuring both libxml-1.x and libxml-2.x compatibility</h3>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3449
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3450<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^]3451to allow smooth upgrade of existing libxml v1code while retaining
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3452compatibility. They offers the following:</p>
3453<ol>
3454 <li>similar include naming, one should use
3455 <strong>#include&lt;libxml/...&gt;</strong> in both cases.</li>
3456 <li>similar identifiers defined via macros for the child and root fields:
3457 respectively <strong>xmlChildrenNode</strong> and
3458 <strong>xmlRootNode</strong></li>
3459 <li>a new macro <strong>LIBXML_TEST_VERSION</strong> which should be
3460 inserted once in the client code</li>
3461</ol>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3462
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3463<p>So the roadmap to upgrade your existing libxml applications is the
3464following:</p>
3465<ol>
3466 <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^]3467 <li>find all occurrences where the xmlDoc <strong>root</strong> field is
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3468 used and change it to <strong>xmlRootNode</strong></li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]3469 <li>similarly find all occurrences where the xmlNode <strong>childs</strong>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3470 field is used and change it to <strong>xmlChildrenNode</strong></li>
3471 <li>add a <strong>LIBXML_TEST_VERSION</strong> macro somewhere in your
3472 <strong>main()</strong> or in the library init entry point</li>
3473 <li>Recompile, check compatibility, it should still work</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]3474 <li>Change your configure script to look first for xml2-config and fall back
3475 using xml-config . Use the --cflags and --libs output of the command as
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3476 the Include and Linking parameters needed to use libxml.</li>
3477 <li>install libxml2-2.3.x and libxml2-devel-2.3.x (libxml-1.8.y and
3478 libxml-devel-1.8.y can be kept simultaneously)</li>
3479 <li>remove your config.cache, relaunch your configuration mechanism, and
3480 recompile, if steps 2 and 3 were done right it should compile as-is</li>
3481 <li>Test that your application is still running correctly, if not this may
3482 be due to extra empty nodes due to formating spaces being kept in libxml2
3483 contrary to libxml1, in that case insert xmlKeepBlanksDefault(1) in your
3484 code before calling the parser (next to
3485 <strong>LIBXML_TEST_VERSION</strong> is a fine place).</li>
3486</ol>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3487
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3488<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]3489
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3490<p>Let me put some emphasis on the fact that there is far more changes from
3491libxml 1.x to 2.x than the ones you may have to patch for. The overall code
3492has been considerably cleaned up and the conformance to the XML specification
3493has been drastically improved too. Don't take those changes as an excuse to
3494not upgrade, it may cost a lot on the long term ...</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3495
Daniel Veillard52dcab32001-10-30 12:51:17 +0000[diff] [blame]3496<h2><a name="Thread">Thread safety</a></h2>
3497
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]3498<p>Starting with 2.4.7, libxml makes provisions to ensure that concurrent
Daniel Veillard52dcab32001-10-30 12:51:17 +0000[diff] [blame]3499threads can safely work in parallel parsing different documents. There is
3500however a couple of things to do to ensure it:</p>
3501<ul>
3502 <li>configure the library accordingly using the --with-threads options</li>
3503 <li>call xmlInitParser() in the "main" thread before using any of the
3504 libxml API (except possibly selecting a different memory allocator)</li>
3505</ul>
3506
3507<p>Note that the thread safety cannot be ensured for multiple threads sharing
3508the same document, the locking must be done at the application level, libxml
3509exports a basic mutex and reentrant mutexes API in &lt;libxml/threads.h&gt;.
3510The parts of the library checked for thread safety are:</p>
3511<ul>
3512 <li>concurrent loading</li>
3513 <li>file access resolution</li>
3514 <li>catalog access</li>
3515 <li>catalog building</li>
3516 <li>entities lookup/accesses</li>
3517 <li>validation</li>
3518 <li>global variables per-thread override</li>
3519 <li>memory handling</li>
3520</ul>
3521
3522<p>XPath is supposed to be thread safe now, but this wasn't tested
3523seriously.</p>
3524
Daniel Veillard35008381999-10-25 13:15:52 +0000[diff] [blame]3525<h2><a name="DOM"></a><a name="Principles">DOM Principles</a></h2>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3526
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3527<p><a href="http://www.w3.org/DOM/">DOM</a> stands for the <em>Document
3528Object Model</em>; this is an API for accessing XML or HTML structured
3529documents. Native support for DOM in Gnome is on the way (module gnome-dom),
3530and will be based on gnome-xml. This will be a far cleaner interface to
3531manipulate XML files within Gnome since it won't expose the internal
3532structure.</p>
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3533
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3534<p>The current DOM implementation on top of libxml is the <a
Daniel Veillarda47fb3d2001-03-25 17:23:49 +0000[diff] [blame]3535href="http://cvs.gnome.org/lxr/source/gdome2/">gdome2 Gnome module</a>, this
3536is a full DOM interface, thanks to Paolo Casarini, check the <a
3537href="http://www.cs.unibo.it/~casarini/gdome2/">Gdome2 homepage</a> for more
3538informations.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3539
Daniel Veillard35008381999-10-25 13:15:52 +0000[diff] [blame]3540<h2><a name="Example"></a><a name="real">A real example</a></h2>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3541
3542<p>Here is a real size example, where the actual content of the application
3543data 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]3544a proposal to keep a database of jobs related to Gnome, with an XML based
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3545storage structure. Here is an <a href="gjobs.xml">XML encoded jobs
3546base</a>:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3547<pre>&lt;?xml version="1.0"?&gt;
3548&lt;gjob:Helping xmlns:gjob="http://www.gnome.org/some-location"&gt;
3549 &lt;gjob:Jobs&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3550
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3551 &lt;gjob:Job&gt;
3552 &lt;gjob:Project ID="3"/&gt;
3553 &lt;gjob:Application&gt;GBackup&lt;/gjob:Application&gt;
3554 &lt;gjob:Category&gt;Development&lt;/gjob:Category&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3555
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3556 &lt;gjob:Update&gt;
3557 &lt;gjob:Status&gt;Open&lt;/gjob:Status&gt;
3558 &lt;gjob:Modified&gt;Mon, 07 Jun 1999 20:27:45 -0400 MET DST&lt;/gjob:Modified&gt;
3559 &lt;gjob:Salary&gt;USD 0.00&lt;/gjob:Salary&gt;
3560 &lt;/gjob:Update&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3561
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3562 &lt;gjob:Developers&gt;
3563 &lt;gjob:Developer&gt;
3564 &lt;/gjob:Developer&gt;
3565 &lt;/gjob:Developers&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3566
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3567 &lt;gjob:Contact&gt;
3568 &lt;gjob:Person&gt;Nathan Clemons&lt;/gjob:Person&gt;
3569 &lt;gjob:Email&gt;nathan@windsofstorm.net&lt;/gjob:Email&gt;
3570 &lt;gjob:Company&gt;
3571 &lt;/gjob:Company&gt;
3572 &lt;gjob:Organisation&gt;
3573 &lt;/gjob:Organisation&gt;
3574 &lt;gjob:Webpage&gt;
3575 &lt;/gjob:Webpage&gt;
3576 &lt;gjob:Snailmail&gt;
3577 &lt;/gjob:Snailmail&gt;
3578 &lt;gjob:Phone&gt;
3579 &lt;/gjob:Phone&gt;
3580 &lt;/gjob:Contact&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3581
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3582 &lt;gjob:Requirements&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3583 The program should be released as free software, under the GPL.
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3584 &lt;/gjob:Requirements&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3585
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3586 &lt;gjob:Skills&gt;
3587 &lt;/gjob:Skills&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3588
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3589 &lt;gjob:Details&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3590 A GNOME based system that will allow a superuser to configure
3591 compressed and uncompressed files and/or file systems to be backed
3592 up with a supported media in the system. This should be able to
3593 perform via find commands generating a list of files that are passed
3594 to tar, dd, cpio, cp, gzip, etc., to be directed to the tape machine
3595 or via operations performed on the filesystem itself. Email
3596 notification and GUI status display very important.
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3597 &lt;/gjob:Details&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:Job&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3600
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3601 &lt;/gjob:Jobs&gt;
3602&lt;/gjob:Helping&gt;</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3603
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3604<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^]3605calling only a couple of functions, browsing the tree to gather the data and
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3606generate the internal structures is harder, and more error prone.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3607
3608<p>The suggested principle is to be tolerant with respect to the input
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3609structure. For example, the ordering of the attributes is not significant,
3610the 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]3611depend on the order of the children of a given node, unless it really makes
3612things harder. Here is some code to parse the information for a person:</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3613<pre>/*
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3614 * A person record
3615 */
3616typedef struct person {
3617 char *name;
3618 char *email;
3619 char *company;
3620 char *organisation;
3621 char *smail;
3622 char *webPage;
3623 char *phone;
3624} person, *personPtr;
3625
3626/*
3627 * And the code needed to parse it
3628 */
3629personPtr parsePerson(xmlDocPtr doc, xmlNsPtr ns, xmlNodePtr cur) {
3630 personPtr ret = NULL;
3631
3632DEBUG("parsePerson\n");
3633 /*
3634 * allocate the struct
3635 */
3636 ret = (personPtr) malloc(sizeof(person));
3637 if (ret == NULL) {
3638 fprintf(stderr,"out of memory\n");
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3639 return(NULL);
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3640 }
3641 memset(ret, 0, sizeof(person));
3642
3643 /* We don't care what the top level element name is */
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3644 cur = cur-&gt;xmlChildrenNode;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3645 while (cur != NULL) {
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3646 if ((!strcmp(cur-&gt;name, "Person")) &amp;&amp; (cur-&gt;ns == ns))
3647 ret-&gt;name = xmlNodeListGetString(doc, cur-&gt;xmlChildrenNode, 1);
3648 if ((!strcmp(cur-&gt;name, "Email")) &amp;&amp; (cur-&gt;ns == ns))
3649 ret-&gt;email = xmlNodeListGetString(doc, cur-&gt;xmlChildrenNode, 1);
3650 cur = cur-&gt;next;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3651 }
3652
3653 return(ret);
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3654}</pre>
3655
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3656<p>Here are a couple of things to notice:</p>
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3657<ul>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3658 <li>Usually a recursive parsing style is the more convenient one: XML data
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]3659 is by nature subject to repetitive constructs and usually exhibits highly
3660 structured patterns.</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3661 <li>The two arguments of type <em>xmlDocPtr</em> and <em>xmlNsPtr</em>,
3662 i.e. the pointer to the global XML document and the namespace reserved to
3663 the application. Document wide information are needed for example to
3664 decode entities and it's a good coding practice to define a namespace for
3665 your application set of data and test that the element and attributes
3666 you're analyzing actually pertains to your application space. This is
3667 done by a simple equality test (cur-&gt;ns == ns).</li>
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]3668 <li>To retrieve text and attributes value, you can use the function
3669 <em>xmlNodeListGetString</em> to gather all the text and entity reference
3670 nodes generated by the DOM output and produce an single text string.</li>
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3671</ul>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3672
3673<p>Here is another piece of code used to parse another level of the
3674structure:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3675<pre>#include &lt;libxml/tree.h&gt;
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]3676/*
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3677 * a Description for a Job
3678 */
3679typedef struct job {
3680 char *projectID;
3681 char *application;
3682 char *category;
3683 personPtr contact;
3684 int nbDevelopers;
3685 personPtr developers[100]; /* using dynamic alloc is left as an exercise */
3686} job, *jobPtr;
3687
3688/*
3689 * And the code needed to parse it
3690 */
3691jobPtr parseJob(xmlDocPtr doc, xmlNsPtr ns, xmlNodePtr cur) {
3692 jobPtr ret = NULL;
3693
3694DEBUG("parseJob\n");
3695 /*
3696 * allocate the struct
3697 */
3698 ret = (jobPtr) malloc(sizeof(job));
3699 if (ret == NULL) {
3700 fprintf(stderr,"out of memory\n");
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3701 return(NULL);
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3702 }
3703 memset(ret, 0, sizeof(job));
3704
3705 /* We don't care what the top level element name is */
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3706 cur = cur-&gt;xmlChildrenNode;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3707 while (cur != NULL) {
3708
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3709 if ((!strcmp(cur-&gt;name, "Project")) &amp;&amp; (cur-&gt;ns == ns)) {
3710 ret-&gt;projectID = xmlGetProp(cur, "ID");
3711 if (ret-&gt;projectID == NULL) {
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3712 fprintf(stderr, "Project has no ID\n");
3713 }
3714 }
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3715 if ((!strcmp(cur-&gt;name, "Application")) &amp;&amp; (cur-&gt;ns == ns))
3716 ret-&gt;application = xmlNodeListGetString(doc, cur-&gt;xmlChildrenNode, 1);
3717 if ((!strcmp(cur-&gt;name, "Category")) &amp;&amp; (cur-&gt;ns == ns))
3718 ret-&gt;category = xmlNodeListGetString(doc, cur-&gt;xmlChildrenNode, 1);
3719 if ((!strcmp(cur-&gt;name, "Contact")) &amp;&amp; (cur-&gt;ns == ns))
3720 ret-&gt;contact = parsePerson(doc, ns, cur);
3721 cur = cur-&gt;next;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3722 }
3723
3724 return(ret);
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3725}</pre>
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3726
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]3727<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^]3728boring. Ultimately, it could be possible to write stubbers taking either C
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3729data structure definitions, a set of XML examples or an XML DTD and produce
3730the code needed to import and export the content between C data and XML
3731storage. This is left as an exercise to the reader :-)</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3732
Daniel Veillard6f0adb52000-07-03 11:41:26 +0000[diff] [blame]3733<p>Feel free to use <a href="example/gjobread.c">the code for the full C
3734parsing example</a> as a template, it is also available with Makefile in the
3735Gnome CVS base under gnome-xml/example</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3736
Daniel Veillardc310d562000-06-23 18:32:15 +0000[diff] [blame]3737<h2><a name="Contributi">Contributions</a></h2>
3738<ul>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3739 <li>Bjorn Reese, William Brack and Thomas Broyer have provided a number of
3740 patches, Gary Pennington worked on the validation API, threading support
3741 and Solaris port.</li>
3742 <li>John Fleck helps maintaining the documentation and man pages.</li>
Daniel Veillardb2fb8ed2002-04-01 09:33:12 +0000[diff] [blame]3743 <li><a href="mailto:igor@stud.fh-frankfurt.de">Igor Zlatkovic</a> is now
3744 the maintainer of the Windows port, <a
Daniel Veillard95189532001-07-26 18:30:26 +0000[diff] [blame]3745 href="http://www.fh-frankfurt.de/~igor/projects/libxml/index.html">he
3746 provides binaries</a></li>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]3747 <li><a href="mailto:Gary.Pennington@sun.com">Gary Pennington</a> provides
3748 <a href="http://garypennington.net/libxml2/">Solaris binaries</a></li>
Daniel Veillarde356c282001-03-10 12:32:04 +0000[diff] [blame]3749 <li><a
3750 href="http://mail.gnome.org/archives/xml/2001-March/msg00014.html">Matt
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame^]3751 Sergeant</a> developed <a
3752 href="http://axkit.org/download/">XML::LibXSLT</a>, a Perl wrapper for
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]3753 libxml2/libxslt as part of the <a href="http://axkit.com/">AxKit XML
3754 application server</a></li>
3755 <li><a href="mailto:fnatter@gmx.net">Felix Natter</a> and <a
3756 href="mailto:geertk@ai.rug.nl">Geert Kloosterman</a> provide <a
Daniel Veillardca989762001-06-23 17:39:29 +0000[diff] [blame]3757 href="libxml-doc.el">an emacs module</a> to lookup libxml(2) functions
Daniel Veillard3f6f7f62000-06-30 17:58:25 +0000[diff] [blame]3758 documentation</li>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]3759 <li><a href="mailto:sherwin@nlm.nih.gov">Ziying Sherwin</a> provided <a
3760 href="http://xmlsoft.org/messages/0488.html">man pages</a></li>
Daniel Veillard5168dbf2001-07-07 00:18:23 +0000[diff] [blame]3761 <li>there is a module for <a
3762 href="http://acs-misc.sourceforge.net/nsxml.html">libxml/libxslt support
3763 in OpenNSD/AOLServer</a></li>
Daniel Veillard2d347fa2002-03-17 10:34:11 +0000[diff] [blame]3764 <li><a href="mailto:dkuhlman@cutter.rexx.com">Dave Kuhlman</a> provided the
3765 first version of libxml/libxslt <a
3766 href="http://www.rexx.com/~dkuhlman">wrappers for Python</a></li>
Daniel Veillard1aadc442001-11-28 13:10:32 +0000[diff] [blame]3767 <li>Petr Kozelka provides <a
3768 href="http://sourceforge.net/projects/libxml2-pas">Pascal units to glue
3769 libxml2</a> with Kylix and Delphi and other Pascal compilers</li>
Daniel Veillard2d347fa2002-03-17 10:34:11 +0000[diff] [blame]3770 <li><a href="mailto:aleksey@aleksey.com">Aleksey Sanin</a> implemented the
3771 <a href="http://www.w3.org/Signature/">XML Canonicalization and XML
3772 Digital Signature</a> <a
3773 href="http://www.aleksey.com/xmlsec/">implementations for libxml2</a></li>
Daniel Veillardc310d562000-06-23 18:32:15 +0000[diff] [blame]3774</ul>
3775
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3776<p></p>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]3777</body>
3778</html>