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4<head>
Daniel Veillardec78c0f2000-08-25 10:25:23 +00005 <title>The XML C library for Gnome</title>
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Daniel Veillardec78c0f2000-08-25 10:25:23 +000011<h1 align="center">The XML C library for Gnome</h1>
Daniel Veillardb05deb71999-08-10 19:04:08 +000012
Daniel Veillard9c466822001-10-25 12:03:39 +000013<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 +000016<h1 style="text-align: center">libxml, a.k.a. gnome-xml</h1>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +000017
18<p></p>
Daniel Veillard9c466822001-10-25 12:03:39 +000019
20<p>Libxml is the XML C library developped for the Gnome project. XML itself
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 +000024markup 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 +000026
27<p>Libxml2 implements a number of existing standards related to markup
28languages:</p>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +000029<ul>
Daniel Veillard9c466822001-10-25 12:03:39 +000030 <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 +000036 <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 +000038 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 +000054 <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 +000056 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 +000058</ul>
59
Daniel Veillard9c466822001-10-25 12:03:39 +000060<p>In most cases libxml tries to implement the specifications in a relatively
Daniel Veillarda5393562002-02-20 11:40:49 +000061strict 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 +000064
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 +000067<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 +000072 <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 +000076 <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 Veillard2d347fa2002-03-17 10:34:11 +000082<p>Libxml2 is known to be very portable, the library should build and work
83without serious troubles on a variety of systems (Linux, Unix, Windows,
84CygWin, MacOs, MacOsX, RISC Os, OS/2, VMS, QNX, MVS, ...)</p>
Daniel Veillard9c466822001-10-25 12:03:39 +000085
Daniel Veillard96984452000-08-31 13:50:12 +000086<p>Separate documents:</p>
87<ul>
Daniel Veillardaf43f632002-03-08 15:05:20 +000088 <li><a href="http://xmlsoft.org/XSLT/">the libxslt page</a> providing an
Daniel Veillard2d347fa2002-03-17 10:34:11 +000089 implementation of XSLT 1.0 and common extensions like EXSLT for
90 libxml2</li>
Daniel Veillardc6271d22001-10-27 07:50:58 +000091 <li><a href="http://www.cs.unibo.it/~casarini/gdome2/">the gdome2 page</a>
Daniel Veillard2d347fa2002-03-17 10:34:11 +000092 : a standard DOM2 implementation for libxml2</li>
93 <li><a href="http://www.aleksey.com/xmlsec/">the XMLSec page</a>: an
94 implementation of <a href="http://www.w3.org/TR/xmldsig-core/">W3C XML
95 Digital Signature</a> for libxml2</li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +000096</ul>
97
98<h2><a name="Introducti">Introduction</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +000099
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000100<p>This document describes libxml, the <a
Daniel Veillardec78c0f2000-08-25 10:25:23 +0000101href="http://www.w3.org/XML/">XML</a> C library developped for the <a
102href="http://www.gnome.org/">Gnome</a> project. <a
103href="http://www.w3.org/XML/">XML is a standard</a> for building tag-based
104structured documents/data.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000105
Daniel Veillard0142b842000-01-14 14:45:24 +0000106<p>Here are some key points about libxml:</p>
107<ul>
Daniel Veillard2d347fa2002-03-17 10:34:11 +0000108 <li>Libxml exports Push (progressive) and Pull (blocking) type parser
109 interfaces for both XML and HTML.</li>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000110 <li>Libxml can do DTD validation at parse time, using a parsed document
111 instance, or with an arbitrary DTD.</li>
Daniel Veillard2d347fa2002-03-17 10:34:11 +0000112 <li>Libxml includes complete <a
Daniel Veillard8c2ecaf2001-07-10 17:53:07 +0000113 href="http://www.w3.org/TR/xpath">XPath</a>, <a
114 href="http://www.w3.org/TR/xptr">XPointer</a> and <a
115 href="http://www.w3.org/TR/xinclude">XInclude</a> implementations.</li>
Daniel Veillardec78c0f2000-08-25 10:25:23 +0000116 <li>It is written in plain C, making as few assumptions as possible, and
Daniel Veillard189446d2000-10-13 10:23:06 +0000117 sticking closely to ANSI C/POSIX for easy embedding. Works on
Daniel Veillardab8500d2000-10-15 21:06:19 +0000118 Linux/Unix/Windows, ported to a number of other platforms.</li>
Daniel Veillardec70e912001-02-26 20:10:45 +0000119 <li>Basic support for HTTP and FTP client allowing aplications to fetch
120 remote resources</li>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000121 <li>The design is modular, most of the extensions can be compiled out.</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000122 <li>The internal document repesentation is as close as possible to the <a
123 href="http://www.w3.org/DOM/">DOM</a> interfaces.</li>
124 <li>Libxml also has a <a href="http://www.megginson.com/SAX/index.html">SAX
Daniel Veillard402e8c82000-02-29 22:57:47 +0000125 like interface</a>; the interface is designed to be compatible with <a
126 href="http://www.jclark.com/xml/expat.html">Expat</a>.</li>
Daniel Veillardc575b992002-02-08 13:28:40 +0000127 <li>This library is released under the <a
128 href="http://www.opensource.org/licenses/mit-license.html">MIT
129 Licence</a> see the Copyright file in the distribution for the precise
130 wording.</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000131</ul>
Daniel Veillardccb09631998-10-27 06:21:04 +0000132
Daniel Veillarde0c1d722001-03-21 10:28:36 +0000133<p>Warning: unless you are forced to because your application links with a
Daniel Veillard2d347fa2002-03-17 10:34:11 +0000134Gnome-1.X library requiring it, <strong><span
Daniel Veillarde0c1d722001-03-21 10:28:36 +0000135style="background-color: #FF0000">Do Not Use libxml1</span></strong>, use
136libxml2</p>
137
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000138<h2><a name="FAQ">FAQ</a></h2>
139
140<p>Table of Content:</p>
141<ul>
142 <li><a href="FAQ.html#Licence">Licence(s)</a></li>
143 <li><a href="FAQ.html#Installati">Installation</a></li>
144 <li><a href="FAQ.html#Compilatio">Compilation</a></li>
145 <li><a href="FAQ.html#Developer">Developer corner</a></li>
146</ul>
147
148<h3><a name="Licence">Licence</a>(s)</h3>
149<ol>
150 <li><em>Licensing Terms for libxml</em>
Daniel Veillardc575b992002-02-08 13:28:40 +0000151 <p>libxml is released under the <a
152 href="http://www.opensource.org/licenses/mit-license.html">MIT
153 Licence</a>, see the file Copyright in the distribution for the precise
154 wording</p>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000155 </li>
156 <li><em>Can I embed libxml in a proprietary application ?</em>
Daniel Veillardc575b992002-02-08 13:28:40 +0000157 <p>Yes. The MIT Licence allows you to also keep proprietary the changes
158 you made to libxml, but it would be graceful to provide back bugfixes and
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000159 improvements as patches for possible incorporation in the main
160 development tree</p>
161 </li>
162</ol>
163
164<h3><a name="Installati">Installation</a></h3>
165<ol>
166 <li>Unless you are forced to because your application links with a Gnome
167 library requiring it, <strong><span style="background-color: #FF0000">Do
168 Not Use libxml1</span></strong>, use libxml2</li>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000169 <li><em>Where can I get libxml</em> ?
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000170 <p>The original distribution comes from <a
171 href="ftp://rpmfind.net/pub/libxml/">rpmfind.net</a> or <a
172 href="ftp://ftp.gnome.org/pub/GNOME/stable/sources/libxml/">gnome.org</a></p>
173 <p>Most linux and Bsd distribution includes libxml, this is probably the
174 safer way for end-users</p>
175 <p>David Doolin provides precompiled Windows versions at <a
176 href="http://www.ce.berkeley.edu/~doolin/code/libxmlwin32/ ">http://www.ce.berkeley.edu/~doolin/code/libxmlwin32/</a></p>
177 </li>
178 <li><em>I see libxml and libxml2 releases, which one should I install ?</em>
179 <ul>
180 <li>If you are not concerned by any existing backward compatibility
181 with existing application, install libxml2 only</li>
182 <li>If you are not doing development, you can safely install both.
183 usually the packages <a
184 href="http://rpmfind.net/linux/RPM/libxml.html">libxml</a> and <a
185 href="http://rpmfind.net/linux/RPM/libxml2.html">libxml2</a> are
186 compatible (this is not the case for development packages)</li>
187 <li>If you are a developer and your system provides separate packaging
188 for shared libraries and the development components, it is possible
189 to install libxml and libxml2, and also <a
190 href="http://rpmfind.net/linux/RPM/libxml-devel.html">libxml-devel</a>
191 and <a
192 href="http://rpmfind.net/linux/RPM/libxml2-devel.html">libxml2-devel</a>
193 too for libxml2 &gt;= 2.3.0</li>
194 <li>If you are developing a new application, please develop against
195 libxml2(-devel)</li>
196 </ul>
197 </li>
198 <li><em>I can't install the libxml package it conflicts with libxml0</em>
199 <p>You probably have an old libxml0 package used to provide the shared
200 library for libxml.so.0, you can probably safely remove it. Anyway the
201 libxml packages provided on <a
202 href="ftp://rpmfind.net/pub/libxml/">rpmfind.net</a> provides
203 libxml.so.0</p>
204 </li>
205 <li><em>I can't install the libxml(2) RPM package due to failed
206 dependancies</em>
207 <p>The most generic solution is to refetch the latest src.rpm , and
208 rebuild it locally with</p>
209 <p><code>rpm --rebuild libxml(2)-xxx.src.rpm</code></p>
210 <p>if everything goes well it will generate two binary rpm (one providing
211 the shared libs and xmllint, and the other one, the -devel package
212 providing includes, static libraries and scripts needed to build
213 applications with libxml(2)) that you can install locally.</p>
214 </li>
215</ol>
216
217<h3><a name="Compilatio">Compilation</a></h3>
218<ol>
219 <li><em>What is the process to compile libxml ?</em>
220 <p>As most UNIX libraries libxml follows the "standard":</p>
221 <p><code>gunzip -c xxx.tar.gz | tar xvf -</code></p>
222 <p><code>cd libxml-xxxx</code></p>
223 <p><code>./configure --help</code></p>
224 <p>to see the options, then the compilation/installation proper</p>
225 <p><code>./configure [possible options]</code></p>
226 <p><code>make</code></p>
227 <p><code>make install</code></p>
228 <p>At that point you may have to rerun ldconfig or similar utility to
229 update your list of installed shared libs.</p>
230 </li>
231 <li><em>What other libraries are needed to compile/install libxml ?</em>
232 <p>Libxml does not requires any other library, the normal C ANSI API
233 should be sufficient (please report any violation to this rule you may
234 find).</p>
235 <p>However if found at configuration time libxml will detect and use the
236 following libs:</p>
237 <ul>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000238 <li><a href="http://www.info-zip.org/pub/infozip/zlib/">libz</a> : a
239 highly portable and available widely compression library</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000240 <li>iconv: a powerful character encoding conversion library. It's
241 included by default on recent glibc libraries, so it doesn't need to
242 be installed specifically on linux. It seems it's now <a
243 href="http://www.opennc.org/onlinepubs/7908799/xsh/iconv.html">part
244 of the official UNIX</a> specification. Here is one <a
245 href="http://clisp.cons.org/~haible/packages-libiconv.html">implementation
246 of the library</a> which source can be found <a
247 href="ftp://ftp.ilog.fr/pub/Users/haible/gnu/">here</a>.</li>
248 </ul>
249 </li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000250 <li><em>make check fails on some platforms</em>
251 <p>Sometime the regression tests results don't completely match the value
252 produced by the parser, and the makefile uses diff to print the delta. On
253 some platforms the diff return breaks the compilation process, if the
Daniel Veillarde46182c2002-02-12 14:29:11 +0000254 diff is small this is probably not a serious problem.</p>
255 <p>Sometimes (especially on Solaris) make checks fails due to limitations
256 in make. Try using GNU-make instead.</p>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000257 </li>
258 <li><em>I use the CVS version and there is no configure script</em>
259 <p>The configure (and other Makefiles) are generated. Use the autogen.sh
260 script to regenerate the configure and Makefiles, like:</p>
261 <p><code>./autogen.sh --prefix=/usr --disable-shared</code></p>
262 </li>
263 <li><em>I have troubles when running make tests with gcc-3.0</em>
264 <p>It seems the initial release of gcc-3.0 has a problem with the
265 optimizer which miscompiles the URI module. Please use another
266 compiler</p>
267 </li>
268</ol>
269
270<h3><a name="Developer">Developer</a> corner</h3>
271<ol>
272 <li><em>xmlDocDump() generates output on one line</em>
273 <p>libxml will not <strong>invent</strong> spaces in the content of a
274 document since <strong>all spaces in the content of a document are
275 significant</strong>. If you build a tree from the API and want
276 indentation:</p>
277 <ol>
278 <li>the correct way is to generate those yourself too</li>
279 <li>the dangerous way is to ask libxml to add those blanks to your
280 content <strong>modifying the content of your document in the
281 process</strong>. The result may not be what you expect. There is
282 <strong>NO</strong> way to guarantee that such a modification won't
283 impact other part of the content of your document. See <a
284 href="http://xmlsoft.org/html/libxml-parser.html#XMLKEEPBLANKSDEFAULT">xmlKeepBlanksDefault
285 ()</a> and <a
286 href="http://xmlsoft.org/html/libxml-tree.html#XMLSAVEFORMATFILE">xmlSaveFormatFile
287 ()</a></li>
288 </ol>
289 </li>
290 <li>Extra nodes in the document:
291 <p><em>For a XML file as below:</em></p>
292 <pre>&lt;?xml version="1.0"?&gt;
293&lt;PLAN xmlns="http://www.argus.ca/autotest/1.0/"&gt;
294&lt;NODE CommFlag="0"/&gt;
295&lt;NODE CommFlag="1"/&gt;
296&lt;/PLAN&gt;</pre>
297 <p><em>after parsing it with the function
298 pxmlDoc=xmlParseFile(...);</em></p>
299 <p><em>I want to the get the content of the first node (node with the
300 CommFlag="0")</em></p>
301 <p><em>so I did it as following;</em></p>
302 <pre>xmlNodePtr pode;
303pnode=pxmlDoc-&gt;children-&gt;children;</pre>
304 <p><em>but it does not work. If I change it to</em></p>
305 <pre>pnode=pxmlDoc-&gt;children-&gt;children-&gt;next;</pre>
306 <p><em>then it works. Can someone explain it to me.</em></p>
307 <p></p>
308 <p>In XML all characters in the content of the document are significant
309 <strong>including blanks and formatting line breaks</strong>.</p>
310 <p>The extra nodes you are wondering about are just that, text nodes with
311 the formatting spaces wich are part of the document but that people tend
312 to forget. There is a function <a
313 href="http://xmlsoft.org/html/libxml-parser.html">xmlKeepBlanksDefault
314 ()</a> to remove those at parse time, but that's an heuristic, and its
315 use should be limited to case where you are sure there is no
316 mixed-content in the document.</p>
317 </li>
318 <li><em>I get compilation errors of existing code like when accessing
319 <strong>root</strong> or <strong>childs fields</strong> of nodes</em>
320 <p>You are compiling code developed for libxml version 1 and using a
321 libxml2 development environment. Either switch back to libxml v1 devel or
322 even better fix the code to compile with libxml2 (or both) by <a
323 href="upgrade.html">following the instructions</a>.</p>
324 </li>
325 <li><em>I get compilation errors about non existing
326 <strong>xmlRootNode</strong> or <strong>xmlChildrenNode</strong>
327 fields</em>
328 <p>The source code you are using has been <a
329 href="upgrade.html">upgraded</a> to be able to compile with both libxml
330 and libxml2, but you need to install a more recent version:
331 libxml(-devel) &gt;= 1.8.8 or libxml2(-devel) &gt;= 2.1.0</p>
332 </li>
333 <li><em>XPath implementation looks seriously broken</em>
334 <p>XPath implementation prior to 2.3.0 was really incomplete, upgrade to
Daniel Veillard2d347fa2002-03-17 10:34:11 +0000335 a recent version, there is no known bug in the current version.</p>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000336 </li>
337 <li><em>The example provided in the web page does not compile</em>
338 <p>It's hard to maintain the documentation in sync with the code
339 &lt;grin/&gt; ...</p>
340 <p>Check the previous points 1/ and 2/ raised before, and send
341 patches.</p>
342 </li>
343 <li><em>Where can I get more examples and informations than in the web
344 page</em>
345 <p>Ideally a libxml book would be nice. I have no such plan ... But you
346 can:</p>
347 <ul>
348 <li>check more deeply the <a href="html/libxml-lib.html">existing
349 generated doc</a></li>
350 <li>looks for examples of use for libxml function using the Gnome code
351 for example the following will query the full Gnome CVs base for the
352 use of the <strong>xmlAddChild()</strong> function:
353 <p><a
354 href="http://cvs.gnome.org/lxr/search?string=xmlAddChild">http://cvs.gnome.org/lxr/search?string=xmlAddChild</a></p>
355 <p>This may be slow, a large hardware donation to the gnome project
356 could cure this :-)</p>
357 </li>
358 <li><a
359 href="http://cvs.gnome.org/bonsai/rview.cgi?cvsroot=/cvs/gnome&amp;dir=gnome-xml">Browse
Daniel Veillardaf43f632002-03-08 15:05:20 +0000360 the libxml source</a> , I try to write code as clean and documented
Daniel Veillard2d347fa2002-03-17 10:34:11 +0000361 as possible, so looking at it may be helpful. Especially the code of
362 xmllint.c and of the various testXXX.c tests programs should provide
363 good example on how to do things with the library.</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000364 </ul>
365 </li>
366 <li>What about C++ ?
367 <p>libxml is written in pure C in order to allow easy reuse on a number
368 of platforms, including embedded systems. I don't intend to convert to
369 C++.</p>
370 <p>There is however a C++ wrapper provided by Ari Johnson
371 &lt;ari@btigate.com&gt; which may fullfill your needs:</p>
372 <p>Website: <a
373 href="http://lusis.org/~ari/xml++/">http://lusis.org/~ari/xml++/</a></p>
374 <p>Download: <a
375 href="http://lusis.org/~ari/xml++/libxml++.tar.gz">http://lusis.org/~ari/xml++/libxml++.tar.gz</a></p>
376 </li>
377 <li>How to validate a document a posteriori ?
378 <p>It is possible to validate documents which had not been validated at
379 initial parsing time or documents who have been built from scratch using
380 the API. Use the <a
381 href="http://xmlsoft.org/html/libxml-valid.html#XMLVALIDATEDTD">xmlValidateDtd()</a>
382 function. It is also possible to simply add a Dtd to an existing
383 document:</p>
384 <pre>xmlDocPtr doc; /* your existing document */
385 xmlDtdPtr dtd = xmlParseDTD(NULL, filename_of_dtd); /* parse the DTD */
386 dtd-&gt;name = xmlStrDup((xmlChar*)"root_name"); /* use the given root */
387
388 doc-&gt;intSubset = dtd;
389 if (doc-&gt;children == NULL) xmlAddChild((xmlNodePtr)doc, (xmlNodePtr)dtd);
390 else xmlAddPrevSibling(doc-&gt;children, (xmlNodePtr)dtd);
391 </pre>
392 </li>
393 <li>etc ...</li>
394</ol>
395
396<p></p>
397
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000398<h2><a name="Documentat">Documentation</a></h2>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000399
Daniel Veillard402e8c82000-02-29 22:57:47 +0000400<p>There are some on-line resources about using libxml:</p>
Daniel Veillard0142b842000-01-14 14:45:24 +0000401<ol>
Daniel Veillard365e13b2000-07-02 07:56:37 +0000402 <li>Check the <a href="FAQ.html">FAQ</a></li>
Daniel Veillardc19fccc2000-07-03 11:52:01 +0000403 <li>Check the <a href="http://xmlsoft.org/html/libxml-lib.html">extensive
Daniel Veillard8c6d6af2000-08-25 17:14:13 +0000404 documentation</a> automatically extracted from code comments (using <a
405 href="http://cvs.gnome.org/bonsai/rview.cgi?cvsroot=/cvs/gnome&amp;dir=gtk-doc">gtk
406 doc</a>).</li>
Daniel Veillard8d869642000-07-14 12:12:59 +0000407 <li>Look at the documentation about <a href="encoding.html">libxml
408 internationalization support</a></li>
Daniel Veillardbc66f852002-01-14 09:49:20 +0000409 <li>This page provides a global overview and <a href="example.html">some
Daniel Veillard402e8c82000-02-29 22:57:47 +0000410 examples</a> on how to use libxml.</li>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000411 <li><a href="mailto:james@daa.com.au">James Henstridge</a> wrote <a
Daniel Veillard402e8c82000-02-29 22:57:47 +0000412 href="http://www.daa.com.au/~james/gnome/xml-sax/xml-sax.html">some nice
413 documentation</a> explaining how to use the libxml SAX interface.</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000414 <li>George Lebl wrote <a
415 href="http://www-4.ibm.com/software/developer/library/gnome3/">an article
Daniel Veillard402e8c82000-02-29 22:57:47 +0000416 for IBM developerWorks</a> about using libxml.</li>
Daniel Veillardec303412000-03-24 13:41:54 +0000417 <li>Check <a href="http://cvs.gnome.org/lxr/source/gnome-xml/TODO">the TODO
418 file</a></li>
419 <li>Read the <a href="upgrade.html">1.x to 2.x upgrade path</a>. If you are
420 starting a new project using libxml you should really use the 2.x
421 version.</li>
Daniel Veillard845cce42002-01-09 11:51:37 +0000422 <li>And don't forget to look at the <a
423 href="http://mail.gnome.org/archives/xml/">mailing-list archive</a>.</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000424</ol>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000425
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000426<h2><a name="Reporting">Reporting bugs and getting help</a></h2>
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000427
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000428<p>Well, bugs or missing features are always possible, and I will make a
429point of fixing them in a timely fashion. The best way to report a bug is to
430use the <a href="http://bugzilla.gnome.org/buglist.cgi?product=libxml">Gnome
431bug tracking database</a> (make sure to use the "libxml" module name). I look
432at reports there regularly and it's good to have a reminder when a bug is
Daniel Veillard51095312001-10-28 18:51:57 +0000433still open. Be sure to specify that the bug is for the package libxml.</p>
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000434
Daniel Veillard0142b842000-01-14 14:45:24 +0000435<p>There is also a mailing-list <a
Daniel Veillard3197f162001-04-04 00:40:08 +0000436href="mailto:xml@gnome.org">xml@gnome.org</a> for libxml, with an <a
437href="http://mail.gnome.org/archives/xml/">on-line archive</a> (<a
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000438href="http://xmlsoft.org/messages">old</a>). To subscribe to this list,
439please visit the <a
440href="http://mail.gnome.org/mailman/listinfo/xml">associated Web</a> page and
441follow the instructions. <strong>Do not send code, I won't debug it</strong>
442(but patches are really appreciated!).</p>
Daniel Veillard234547b2001-07-05 09:46:10 +0000443
Daniel Veillard008186f2001-09-13 14:24:44 +0000444<p>Check the following <strong><span style="color: #FF0000">before
445posting</span></strong>:</p>
Daniel Veillard234547b2001-07-05 09:46:10 +0000446<ul>
Daniel Veillarddadd0872001-09-15 09:21:44 +0000447 <li>read the <a href="FAQ.html">FAQ</a></li>
Daniel Veillard234547b2001-07-05 09:46:10 +0000448 <li>make sure you are <a href="ftp://xmlsoft.org/">using a recent
449 version</a>, and that the problem still shows up in those</li>
450 <li>check the <a href="http://mail.gnome.org/archives/xml/">list
451 archives</a> to see if the problem was reported already, in this case
Daniel Veillarde7ead2d2001-08-22 23:44:09 +0000452 there is probably a fix available, similary check the <a
453 href="http://bugzilla.gnome.org/buglist.cgi?product=libxml">registered
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000454 open bugs</a></li>
Daniel Veillard234547b2001-07-05 09:46:10 +0000455 <li>make sure you can reproduce the bug with xmllint or one of the test
456 programs found in source in the distribution</li>
457 <li>Please send the command showing the error as well as the input (as an
458 attachement)</li>
459</ul>
Daniel Veillard0142b842000-01-14 14:45:24 +0000460
Daniel Veillarddadd0872001-09-15 09:21:44 +0000461<p>Then send the bug with associated informations to reproduce it to the <a
Daniel Veillard33a67802001-03-07 09:44:02 +0000462href="mailto:xml@gnome.org">xml@gnome.org</a> list; if it's really libxml
Daniel Veillard008186f2001-09-13 14:24:44 +0000463related I will approve it.. Please do not send me mail directly, it makes
464things really harder to track and in some cases I'm not the best person to
465answer a given question, ask the list instead.</p>
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000466
Daniel Veillard91e9d582001-02-26 07:31:12 +0000467<p>Of course, bugs reported with a suggested patch for fixing them will
Daniel Veillardec303412000-03-24 13:41:54 +0000468probably be processed faster.</p>
469
470<p>If you're looking for help, a quick look at <a
Daniel Veillardf7ed3362001-08-17 12:01:21 +0000471href="http://mail.gnome.org/archives/xml/">the list archive</a> may actually
Daniel Veillardec303412000-03-24 13:41:54 +0000472provide the answer, I usually send source samples when answering libxml usage
Daniel Veillard6f0adb52000-07-03 11:41:26 +0000473questions. The <a href="http://xmlsoft.org/html/book1.html">auto-generated
Daniel Veillardec303412000-03-24 13:41:54 +0000474documentantion</a> is not as polished as I would like (i need to learn more
475about Docbook), but it's a good starting point.</p>
476
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000477<h2><a name="help">How to help</a></h2>
478
479<p>You can help the project in various ways, the best thing to do first is to
480subscribe to the mailing-list as explained before, check the <a
Daniel Veillardf7ed3362001-08-17 12:01:21 +0000481href="http://mail.gnome.org/archives/xml/">archives </a>and the <a
482href="http://bugzilla.gnome.org/buglist.cgi?product=libxml">Gnome bug
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000483database:</a>:</p>
484<ol>
485 <li>provide patches when you find problems</li>
Daniel Veillard189446d2000-10-13 10:23:06 +0000486 <li>provide the diffs when you port libxml to a new platform. They may not
Daniel Veillardab8500d2000-10-15 21:06:19 +0000487 be integrated in all cases but help pinpointing portability problems
488 and</li>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000489 <li>provide documentation fixes (either as patches to the code comments or
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000490 as HTML diffs).</li>
491 <li>provide new documentations pieces (translations, examples, etc ...)</li>
492 <li>Check the TODO file and try to close one of the items</li>
493 <li>take one of the points raised in the archive or the bug database and
Daniel Veillarde7ead2d2001-08-22 23:44:09 +0000494 provide a fix. <a href="mailto:daniel@veillard.com">Get in touch with me
495 </a>before to avoid synchronization problems and check that the suggested
496 fix will fit in nicely :-)</li>
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000497</ol>
498
Daniel Veillard10a2c651999-12-12 13:03:50 +0000499<h2><a name="Downloads">Downloads</a></h2>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000500
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000501<p>The latest versions of libxml can be found on <a
Daniel Veillard20c8cf22001-06-26 22:47:36 +0000502href="ftp://xmlsoft.org/">xmlsoft.org</a> (<a
503href="ftp://speakeasy.rpmfind.net/pub/libxml/">Seattle</a>, <a
504href="ftp://fr.rpmfind.net/pub/libxml/">France</a>) or on the <a
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000505href="ftp://ftp.gnome.org/pub/GNOME/MIRRORS.html">Gnome FTP server</a> either
Daniel Veillard10a2c651999-12-12 13:03:50 +0000506as a <a href="ftp://ftp.gnome.org/pub/GNOME/stable/sources/libxml/">source
Daniel Veillard306be992000-07-03 12:38:45 +0000507archive</a> or <a
Daniel Veillarda41123c2001-04-22 19:31:20 +0000508href="ftp://ftp.gnome.org/pub/GNOME/stable/redhat/i386/libxml/">RPM
509packages</a>. (NOTE that you need both the <a
Daniel Veillardc19fccc2000-07-03 11:52:01 +0000510href="http://rpmfind.net/linux/RPM/libxml2.html">libxml(2)</a> and <a
511href="http://rpmfind.net/linux/RPM/libxml2-devel.html">libxml(2)-devel</a>
Daniel Veillard95189532001-07-26 18:30:26 +0000512packages installed to compile applications using libxml.) <a
513href="mailto:izlatkovic@daenet.de">Igor Zlatkovic</a> is now the maintainer
514of the Windows port, <a
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000515href="http://www.fh-frankfurt.de/~igor/projects/libxml/index.html">he
Daniel Veillardc6271d22001-10-27 07:50:58 +0000516provides binaries</a>. <a href="mailto:Gary.Pennington@sun.com">Gary
Daniel Veillard1aadc442001-11-28 13:10:32 +0000517Pennington</a> provides <a href="http://garypennington.net/libxml2/">Solaris
518binaries</a>.</p>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000519
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000520<p><a name="Snapshot">Snapshot:</a></p>
521<ul>
522 <li>Code from the W3C cvs base libxml <a
Daniel Veillard33a67802001-03-07 09:44:02 +0000523 href="ftp://xmlsoft.org/cvs-snapshot.tar.gz">cvs-snapshot.tar.gz</a></li>
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000524 <li>Docs, content of the web site, the list archive included <a
Daniel Veillard33a67802001-03-07 09:44:02 +0000525 href="ftp://xmlsoft.org/libxml-docs.tar.gz">libxml-docs.tar.gz</a></li>
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000526</ul>
527
Daniel Veillardc6271d22001-10-27 07:50:58 +0000528<p><a name="Contribs">Contributions:</a></p>
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000529
530<p>I do accept external contributions, especially if compiling on another
Daniel Veillardc6271d22001-10-27 07:50:58 +0000531platform, get in touch with me to upload the package, wrappers for various
Daniel Veillard51095312001-10-28 18:51:57 +0000532languages have been provided, and can be found in the <a
533href="contribs.html">contrib section</a></p>
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000534
Daniel Veillard82687162001-01-22 15:32:01 +0000535<p>Libxml is also available from CVS:</p>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000536<ul>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000537 <li><p>The <a
538 href="http://cvs.gnome.org/bonsai/rview.cgi?cvsroot=/cvs/gnome&amp;dir=gnome-xml">Gnome
Daniel Veillard402e8c82000-02-29 22:57:47 +0000539 CVS base</a>. Check the <a
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000540 href="http://developer.gnome.org/tools/cvs.html">Gnome CVS Tools</a>
541 page; the CVS module is <b>gnome-xml</b>.</p>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000542 </li>
Daniel Veillard82687162001-01-22 15:32:01 +0000543 <li>The <strong>libxslt</strong> module is also present there</li>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000544</ul>
545
546<h2><a name="News">News</a></h2>
547
Daniel Veillard944b5ff1999-12-15 19:08:24 +0000548<h3>CVS only : check the <a
549href="http://cvs.gnome.org/lxr/source/gnome-xml/ChangeLog">Changelog</a> file
Daniel Veillard189446d2000-10-13 10:23:06 +0000550for a really accurate description</h3>
Daniel Veillardab8500d2000-10-15 21:06:19 +0000551
Daniel Veillard91e9d582001-02-26 07:31:12 +0000552<p>Items floating around but not actively worked on, get in touch with me if
Daniel Veillardab8500d2000-10-15 21:06:19 +0000553you want to test those</p>
554<ul>
Daniel Veillard28929b22000-11-13 18:22:49 +0000555 <li>Finishing up <a href="http://www.w3.org/TR/xptr">XPointer</a> and <a
556 href="http://www.w3.org/TR/xinclude">XInclude</a></li>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000557</ul>
558
Daniel Veillard34ce8be2002-03-18 19:37:11 +0000559<h3>2.4.18: Mar 18 2002</h3>
560<ul>
561 <li>bug fixes: tree, SAX, canonicalization, validation, portability,
562 xpath</li>
563 <li>removed the --with-buffer option it was becoming unmaintainable</li>
564 <li>serious cleanup of the Python makefiles</li>
565 <li>speedup patch to XPath very effective for DocBook stylesheets</li>
566 <li>Fixes for Windows build, cleanup of the documentation</li>
567</ul>
568
Daniel Veillardaf43f632002-03-08 15:05:20 +0000569<h3>2.4.17: Mar 8 2002</h3>
570<ul>
571 <li>a lot of bug fixes, including "namespace nodes have no parents in
572 XPath"</li>
573 <li>fixed/improved the Python wrappers, added more examples and more
574 regression tests, XPath extension functions can now return node-sets</li>
575 <li>added the XML Canonalization support from Aleksey Sanin</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000576</ul>
577
Daniel Veillard5f4b5992002-02-20 10:22:49 +0000578<h3>2.4.16: Feb 20 2002</h3>
579<ul>
580 <li>a lot of bug fixes, most of them were triggered by the XML Testsuite
581 from OASIS and W3C. Compliance has been significantly improved.</li>
582 <li>a couple of portability fixes too.</li>
583</ul>
584
Daniel Veillard397ff112002-02-11 18:27:20 +0000585<h3>2.4.15: Feb 11 2002</h3>
586<ul>
587 <li>Fixed the Makefiles, especially the python module ones</li>
588 <li>A few bug fixes and cleanup</li>
589 <li>Includes cleanup</li>
590</ul>
591
Daniel Veillardb6c1e2f2002-02-08 14:52:52 +0000592<h3>2.4.14: Feb 8 2002</h3>
593<ul>
594 <li>Change of Licence to the <a
595 href="http://www.opensource.org/licenses/mit-license.html">MIT
596 Licence</a> basisally for integration in XFree86 codebase, and removing
597 confusion around the previous dual-licencing</li>
598 <li>added Python bindings, beta software but should already be quite
599 complete</li>
600 <li>a large number of fixes and cleanups, especially for all tree
601 manipulations</li>
602 <li>cleanup of the headers, generation of a reference API definition in
603 XML</li>
604</ul>
605
606<h3>2.4.13: Jan 14 2002</h3>
Daniel Veillard744683d2002-01-14 17:30:20 +0000607<ul>
608 <li>update of the documentation: John Fleck and Charlie Bozeman</li>
609 <li>cleanup of timing code from Justin Fletcher</li>
610 <li>fixes for Windows and initial thread support on Win32: Igor and Serguei
611 Narojnyi</li>
612 <li>Cygwin patch from Robert Collins</li>
613 <li>added xmlSetEntityReferenceFunc() for Keith Isdale work on xsldbg</li>
614</ul>
615
Daniel Veillardef90ba72001-12-07 14:24:22 +0000616<h3>2.4.12: Dec 7 2001</h3>
617<ul>
618 <li>a few bug fixes: thread (Gary Pennington), xmllint (Geert Kloosterman),
619 XML parser (Robin Berjon), XPointer (Danny Jamshy), I/O cleanups
620 (robert)</li>
621 <li>Eric Lavigne contributed project files for MacOS</li>
622 <li>some makefiles cleanups</li>
623</ul>
624
Daniel Veillarda4871052001-11-26 13:19:48 +0000625<h3>2.4.11: Nov 26 2001</h3>
626<ul>
627 <li>fixed a couple of errors in the includes, fixed a few bugs, some code
628 cleanups</li>
629 <li>xmllint man pages improvement by Heiko Rupp</li>
630 <li>updated VMS build instructions from John A Fotheringham</li>
631 <li>Windows Makefiles updates from Igor</li>
632</ul>
633
Daniel Veillard43d3f612001-11-10 11:57:23 +0000634<h3>2.4.10: Nov 10 2001</h3>
635<ul>
636 <li>URI escaping fix (Joel Young)</li>
637 <li>added xmlGetNodePath() (for paths or XPointers generation)</li>
638 <li>Fixes namespace handling problems when using DTD and validation</li>
639 <li>improvements on xmllint: Morus Walter patches for --format and
640 --encode, Stefan Kost and Heiko Rupp improvements on the --shell</li>
641 <li>fixes for xmlcatalog linking pointed by Weiqi Gao</li>
642 <li>fixes to the HTML parser</li>
643</ul>
644
645<h3>2.4.9: Nov 6 2001</h3>
646<ul>
647 <li>fixes more catalog bugs</li>
648 <li>avoid a compilation problem, improve xmlGetLineNo()</li>
649</ul>
650
Daniel Veillarded421aa2001-11-04 21:22:45 +0000651<h3>2.4.8: Nov 4 2001</h3>
652<ul>
653 <li>fixed SGML catalogs broken in previous release, updated xmlcatalog
654 tool</li>
655 <li>fixed a compile errors and some includes troubles.</li>
656</ul>
657
Daniel Veillard52dcab32001-10-30 12:51:17 +0000658<h3>2.4.7: Oct 30 2001</h3>
659<ul>
660 <li>exported some debugging interfaces</li>
661 <li>serious rewrite of the catalog code</li>
662 <li>integrated Gary Pennington thread safety patch, added configure option
663 and regression tests</li>
664 <li>removed an HTML parser bug</li>
665 <li>fixed a couple of potentially serious validation bugs</li>
666 <li>integrated the SGML DocBook support in xmllint</li>
667 <li>changed the nanoftp anonymous login passwd</li>
668 <li>some I/O cleanup and a couple of interfaces for Perl wrapper</li>
669 <li>general bug fixes</li>
670 <li>updated xmllint man page by John Fleck</li>
671 <li>some VMS and Windows updates</li>
672</ul>
673
Daniel Veillard60087f32001-10-10 09:45:09 +0000674<h3>2.4.6: Oct 10 2001</h3>
675<ul>
Daniel Veillard52dcab32001-10-30 12:51:17 +0000676 <li>added an updated man pages by John Fleck</li>
Daniel Veillard60087f32001-10-10 09:45:09 +0000677 <li>portability and configure fixes</li>
678 <li>an infinite loop on the HTML parser was removed (William)</li>
679 <li>Windows makefile patches from Igor</li>
680 <li>fixed half a dozen bugs reported fof libxml or libxslt</li>
681 <li>updated xmlcatalog to be able to modify SGML super catalogs</li>
682</ul>
683
Daniel Veillarddadd0872001-09-15 09:21:44 +0000684<h3>2.4.5: Sep 14 2001</h3>
685<ul>
686 <li>Remove a few annoying bugs in 2.4.4</li>
687 <li>forces the HTML serializer to output decimal charrefs since some
688 version of Netscape can't handle hexadecimal ones</li>
689</ul>
690
691<h3>1.8.16: Sep 14 2001</h3>
692<ul>
693 <li>maintenance release of the old libxml1 branch, couple of bug and
694 portability fixes</li>
695</ul>
696
Daniel Veillard04382ae2001-09-12 18:51:30 +0000697<h3>2.4.4: Sep 12 2001</h3>
698<ul>
699 <li>added --convert to xmlcatalog, bug fixes and cleanups of XML
700 Catalog</li>
701 <li>a few bug fixes and some portability changes</li>
702 <li>some documentation cleanups</li>
703</ul>
704
Daniel Veillard39936902001-08-24 00:49:01 +0000705<h3>2.4.3: Aug 23 2001</h3>
706<ul>
707 <li>XML Catalog support see the doc</li>
708 <li>New NaN/Infinity floating point code</li>
709 <li>A few bug fixes</li>
710</ul>
711
712<h3>2.4.2: Aug 15 2001</h3>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000713<ul>
714 <li>adds xmlLineNumbersDefault() to control line number generation</li>
715 <li>lot of bug fixes</li>
716 <li>the Microsoft MSC projects files shuld now be up to date</li>
717 <li>inheritance of namespaces from DTD defaulted attributes</li>
718 <li>fixes a serious potential security bug</li>
719 <li>added a --format option to xmllint</li>
720</ul>
721
722<h3>2.4.1: July 24 2001</h3>
723<ul>
724 <li>possibility to keep line numbers in the tree</li>
725 <li>some computation NaN fixes</li>
726 <li>extension of the XPath API</li>
727 <li>cleanup for alpha and ia64 targets</li>
728 <li>patch to allow saving through HTTP PUT or POST</li>
Daniel Veillard09ab7e12001-07-10 15:49:44 +0000729</ul>
730
731<h3>2.4.0: July 10 2001</h3>
732<ul>
733 <li>Fixed a few bugs in XPath, validation, and tree handling.</li>
734 <li>Fixed XML Base implementation, added a coupel of examples to the
735 regression tests</li>
736 <li>A bit of cleanup</li>
Daniel Veillardab8500d2000-10-15 21:06:19 +0000737</ul>
738
Daniel Veillard5b43fde2001-07-05 23:31:40 +0000739<h3>2.3.14: July 5 2001</h3>
740<ul>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000741 <li>fixed some entities problems and reduce mem requirement when
742 substituing them</li>
Daniel Veillard5b43fde2001-07-05 23:31:40 +0000743 <li>lots of improvements in the XPath queries interpreter can be
744 substancially faster</li>
745 <li>Makefiles and configure cleanups</li>
746 <li>Fixes to XPath variable eval, and compare on empty node set</li>
747 <li>HTML tag closing bug fixed</li>
748 <li>Fixed an URI reference computating problem when validating</li>
749</ul>
750
Daniel Veillard2adbb512001-06-28 16:20:36 +0000751<h3>2.3.13: June 28 2001</h3>
752<ul>
753 <li>2.3.12 configure.in was broken as well as the push mode XML parser</li>
754 <li>a few more fixes for compilation on Windows MSC by Yon Derek</li>
755</ul>
756
757<h3>1.8.14: June 28 2001</h3>
758<ul>
759 <li>Zbigniew Chyla gave a patch to use the old XML parser in push mode</li>
760 <li>Small Makefile fix</li>
761</ul>
762
Daniel Veillard11648102001-06-26 16:08:24 +0000763<h3>2.3.12: June 26 2001</h3>
764<ul>
765 <li>lots of cleanup</li>
766 <li>a couple of validation fix</li>
767 <li>fixed line number counting</li>
768 <li>fixed serious problems in the XInclude processing</li>
769 <li>added support for UTF8 BOM at beginning of entities</li>
770 <li>fixed a strange gcc optimizer bugs in xpath handling of float, gcc-3.0
771 miscompile uri.c (William), Thomas Leitner provided a fix for the
772 optimizer on Tru64</li>
773 <li>incorporated Yon Derek and Igor Zlatkovic fixes and improvements for
774 compilation on Windows MSC</li>
775 <li>update of libxml-doc.el (Felix Natter)</li>
776 <li>fixed 2 bugs in URI normalization code</li>
777</ul>
778
Daniel Veillarde3c81b52001-06-17 14:50:34 +0000779<h3>2.3.11: June 17 2001</h3>
780<ul>
781 <li>updates to trio, Makefiles and configure should fix some portability
782 problems (alpha)</li>
783 <li>fixed some HTML serialization problems (pre, script, and block/inline
784 handling), added encoding aware APIs, cleanup of this code</li>
785 <li>added xmlHasNsProp()</li>
786 <li>implemented a specific PI for encoding support in the DocBook SGML
787 parser</li>
788 <li>some XPath fixes (-Infinity, / as a function parameter and namespaces
789 node selection)</li>
790 <li>fixed a performance problem and an error in the validation code</li>
791 <li>fixed XInclude routine to implement the recursive behaviour</li>
792 <li>fixed xmlFreeNode problem when libxml is included statically twice</li>
793 <li>added --version to xmllint for bug reports</li>
794</ul>
795
Daniel Veillard2e4f1882001-06-01 10:11:57 +0000796<h3>2.3.10: June 1 2001</h3>
797<ul>
798 <li>fixed the SGML catalog support</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000799 <li>a number of reported bugs got fixed, in XPath, iconv detection,
800 XInclude processing</li>
Daniel Veillard2e4f1882001-06-01 10:11:57 +0000801 <li>XPath string function should now handle unicode correctly</li>
802</ul>
803
Daniel Veillard4623acd2001-05-19 15:13:15 +0000804<h3>2.3.9: May 19 2001</h3>
805
806<p>Lots of bugfixes, and added a basic SGML catalog support:</p>
807<ul>
808 <li>HTML push bugfix #54891 and another patch from Jonas Borgström</li>
809 <li>some serious speed optimisation again</li>
810 <li>some documentation cleanups</li>
811 <li>trying to get better linking on solaris (-R)</li>
812 <li>XPath API cleanup from Thomas Broyer</li>
813 <li>Validation bug fixed #54631, added a patch from Gary Pennington, fixed
814 xmlValidGetValidElements()</li>
815 <li>Added an INSTALL file</li>
816 <li>Attribute removal added to API: #54433</li>
817 <li>added a basic support for SGML catalogs</li>
818 <li>fixed xmlKeepBlanksDefault(0) API</li>
819 <li>bugfix in xmlNodeGetLang()</li>
820 <li>fixed a small configure portability problem</li>
821 <li>fixed an inversion of SYSTEM and PUBLIC identifier in HTML document</li>
822</ul>
823
Daniel Veillarda265af72001-05-14 11:13:58 +0000824<h3>1.8.13: May 14 2001</h3>
825<ul>
826 <li>bugfixes release of the old libxml1 branch used by Gnome</li>
827</ul>
828
Daniel Veillard3bbbe6f2001-05-03 11:15:37 +0000829<h3>2.3.8: May 3 2001</h3>
830<ul>
831 <li>Integrated an SGML DocBook parser for the Gnome project</li>
832 <li>Fixed a few things in the HTML parser</li>
833 <li>Fixed some XPath bugs raised by XSLT use, tried to fix the floating
834 point portability issue</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000835 <li>Speed improvement (8M/s for SAX, 3M/s for DOM, 1.5M/s for
836 DOM+validation using the XML REC as input and a 700MHz celeron).</li>
Daniel Veillard3bbbe6f2001-05-03 11:15:37 +0000837 <li>incorporated more Windows cleanup</li>
838 <li>added xmlSaveFormatFile()</li>
839 <li>fixed problems in copying nodes with entities references (gdome)</li>
840 <li>removed some troubles surrounding the new validation module</li>
841</ul>
842
Daniel Veillarda41123c2001-04-22 19:31:20 +0000843<h3>2.3.7: April 22 2001</h3>
844<ul>
845 <li>lots of small bug fixes, corrected XPointer</li>
846 <li>Non determinist content model validation support</li>
847 <li>added xmlDocCopyNode for gdome2</li>
848 <li>revamped the way the HTML parser handles end of tags</li>
849 <li>XPath: corrctions of namespacessupport and number formatting</li>
850 <li>Windows: Igor Zlatkovic patches for MSC compilation</li>
851 <li>HTML ouput fixes from P C Chow and William M. Brack</li>
852 <li>Improved validation speed sensible for DocBook</li>
853 <li>fixed a big bug with ID declared in external parsed entities</li>
854 <li>portability fixes, update of Trio from Bjorn Reese</li>
855</ul>
856
Daniel Veillardafc73112001-04-11 11:51:41 +0000857<h3>2.3.6: April 8 2001</h3>
858<ul>
859 <li>Code cleanup using extreme gcc compiler warning options, found and
860 cleared half a dozen potential problem</li>
861 <li>the Eazel team found an XML parser bug</li>
862 <li>cleaned up the user of some of the string formatting function. used the
863 trio library code to provide the one needed when the platform is missing
864 them</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000865 <li>xpath: removed a memory leak and fixed the predicate evaluation
866 problem, extended the testsuite and cleaned up the result. XPointer seems
867 broken ...</li>
Daniel Veillardafc73112001-04-11 11:51:41 +0000868</ul>
869
Daniel Veillard56a4cb82001-03-24 17:00:36 +0000870<h3>2.3.5: Mar 23 2001</h3>
871<ul>
872 <li>Biggest change is separate parsing and evaluation of XPath expressions,
873 there is some new APIs for this too</li>
874 <li>included a number of bug fixes(XML push parser, 51876, notations,
875 52299)</li>
876 <li>Fixed some portability issues</li>
877</ul>
878
Daniel Veillarde356c282001-03-10 12:32:04 +0000879<h3>2.3.4: Mar 10 2001</h3>
880<ul>
881 <li>Fixed bugs #51860 and #51861</li>
882 <li>Added a global variable xmlDefaultBufferSize to allow default buffer
883 size to be application tunable.</li>
884 <li>Some cleanup in the validation code, still a bug left and this part
885 should probably be rewritten to support ambiguous content model :-\</li>
886 <li>Fix a couple of serious bugs introduced or raised by changes in 2.3.3
887 parser</li>
888 <li>Fixed another bug in xmlNodeGetContent()</li>
889 <li>Bjorn fixed XPath node collection and Number formatting</li>
890 <li>Fixed a loop reported in the HTML parsing</li>
891 <li>blank space are reported even if the Dtd content model proves that they
892 are formatting spaces, this is for XmL conformance</li>
893</ul>
894
Daniel Veillardb402c072001-03-01 17:28:58 +0000895<h3>2.3.3: Mar 1 2001</h3>
896<ul>
897 <li>small change in XPath for XSLT</li>
898 <li>documentation cleanups</li>
899 <li>fix in validation by Gary Pennington</li>
900 <li>serious parsing performances improvements</li>
901</ul>
902
Daniel Veillardec70e912001-02-26 20:10:45 +0000903<h3>2.3.2: Feb 24 2001</h3>
Daniel Veillard71681102001-02-24 17:48:53 +0000904<ul>
905 <li>chasing XPath bugs, found a bunch, completed some TODO</li>
906 <li>fixed a Dtd parsing bug</li>
907 <li>fixed a bug in xmlNodeGetContent</li>
908 <li>ID/IDREF support partly rewritten by Gary Pennington</li>
909</ul>
910
Daniel Veillardec70e912001-02-26 20:10:45 +0000911<h3>2.3.1: Feb 15 2001</h3>
Daniel Veillard6e6a6cc2001-02-15 15:55:44 +0000912<ul>
913 <li>some XPath and HTML bug fixes for XSLT</li>
914 <li>small extension of the hash table interfaces for DOM gdome2
915 implementation</li>
916 <li>A few bug fixes</li>
917</ul>
918
Daniel Veillardec70e912001-02-26 20:10:45 +0000919<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 +0000920<ul>
921 <li>Lots of XPath bug fixes</li>
922 <li>Add a mode with Dtd lookup but without validation error reporting for
923 XSLT</li>
924 <li>Add support for text node without escaping (XSLT)</li>
925 <li>bug fixes for xmlCheckFilename</li>
926 <li>validation code bug fixes from Gary Pennington</li>
927 <li>Patch from Paul D. Smith correcting URI path normalization</li>
928 <li>Patch to allow simultaneous install of libxml-devel and
929 libxml2-devel</li>
930 <li>the example Makefile is now fixed</li>
931 <li>added HTML to the RPM packages</li>
932 <li>tree copying bugfixes</li>
933 <li>updates to Windows makefiles</li>
934 <li>optimisation patch from Bjorn Reese</li>
935</ul>
936
Daniel Veillardec70e912001-02-26 20:10:45 +0000937<h3>2.2.11: Jan 4 2001</h3>
Daniel Veillard503b8932001-01-05 06:36:31 +0000938<ul>
939 <li>bunch of bug fixes (memory I/O, xpath, ftp/http, ...)</li>
940 <li>added htmlHandleOmittedElem()</li>
941 <li>Applied Bjorn Reese's IPV6 first patch</li>
942 <li>Applied Paul D. Smith patches for validation of XInclude results</li>
Daniel Veillard82687162001-01-22 15:32:01 +0000943 <li>added XPointer xmlns() new scheme support</li>
Daniel Veillard503b8932001-01-05 06:36:31 +0000944</ul>
945
Daniel Veillard2ddd23d2000-11-25 10:42:19 +0000946<h3>2.2.10: Nov 25 2000</h3>
Daniel Veillard9d343c42000-11-25 10:12:43 +0000947<ul>
948 <li>Fix the Windows problems of 2.2.8</li>
949 <li>integrate OpenVMS patches</li>
950 <li>better handling of some nasty HTML input</li>
951 <li>Improved the XPointer implementation</li>
952 <li>integrate a number of provided patches</li>
953</ul>
954
Daniel Veillard2ddd23d2000-11-25 10:42:19 +0000955<h3>2.2.9: Nov 25 2000</h3>
956<ul>
957 <li>erroneous release :-(</li>
958</ul>
959
Daniel Veillard28929b22000-11-13 18:22:49 +0000960<h3>2.2.8: Nov 13 2000</h3>
961<ul>
962 <li>First version of <a href="http://www.w3.org/TR/xinclude">XInclude</a>
963 support</li>
964 <li>Patch in conditional section handling</li>
965 <li>updated MS compiler project</li>
966 <li>fixed some XPath problems</li>
967 <li>added an URI escaping function</li>
968 <li>some other bug fixes</li>
969</ul>
970
971<h3>2.2.7: Oct 31 2000</h3>
972<ul>
973 <li>added message redirection</li>
974 <li>XPath improvements (thanks TOM !)</li>
975 <li>xmlIOParseDTD() added</li>
976 <li>various small fixes in the HTML, URI, HTTP and XPointer support</li>
977 <li>some cleanup of the Makefile, autoconf and the distribution content</li>
978</ul>
979
Daniel Veillard29a11cc2000-10-25 13:32:39 +0000980<h3>2.2.6: Oct 25 2000:</h3>
981<ul>
982 <li>Added an hash table module, migrated a number of internal structure to
983 those</li>
984 <li>Fixed a posteriori validation problems</li>
985 <li>HTTP module cleanups</li>
986 <li>HTML parser improvements (tag errors, script/style handling, attribute
987 normalization)</li>
988 <li>coalescing of adjacent text nodes</li>
989 <li>couple of XPath bug fixes, exported the internal API</li>
990</ul>
991
Daniel Veillardab8500d2000-10-15 21:06:19 +0000992<h3>2.2.5: Oct 15 2000:</h3>
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000993<ul>
Daniel Veillard189446d2000-10-13 10:23:06 +0000994 <li>XPointer implementation and testsuite</li>
995 <li>Lot of XPath fixes, added variable and functions registration, more
996 tests</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000997 <li>Portability fixes, lots of enhancements toward an easy Windows build
998 and release</li>
Daniel Veillard189446d2000-10-13 10:23:06 +0000999 <li>Late validation fixes</li>
1000 <li>Integrated a lot of contributed patches</li>
1001 <li>added memory management docs</li>
Daniel Veillardab8500d2000-10-15 21:06:19 +00001002 <li>a performance problem when using large buffer seems fixed</li>
Daniel Veillard189446d2000-10-13 10:23:06 +00001003</ul>
1004
1005<h3>2.2.4: Oct 1 2000:</h3>
1006<ul>
1007 <li>main XPath problem fixed</li>
1008 <li>Integrated portability patches for Windows</li>
1009 <li>Serious bug fixes on the URI and HTML code</li>
Daniel Veillard361d8452000-04-03 19:48:13 +00001010</ul>
1011
Daniel Veillardd5f97f82000-09-17 16:38:14 +00001012<h3>2.2.3: Sep 17 2000</h3>
1013<ul>
1014 <li>bug fixes</li>
1015 <li>cleanup of entity handling code</li>
1016 <li>overall review of all loops in the parsers, all sprintf usage has been
1017 checked too</li>
1018 <li>Far better handling of larges Dtd. Validating against Docbook XML Dtd
1019 works smoothly now.</li>
1020</ul>
1021
1022<h3>1.8.10: Sep 6 2000</h3>
1023<ul>
1024 <li>bug fix release for some Gnome projects</li>
1025</ul>
1026
1027<h3>2.2.2: August 12 2000</h3>
Daniel Veillard786d7c82000-08-12 23:38:57 +00001028<ul>
1029 <li>mostly bug fixes</li>
Daniel Veillardec78c0f2000-08-25 10:25:23 +00001030 <li>started adding routines to access xml parser context options</li>
Daniel Veillard786d7c82000-08-12 23:38:57 +00001031</ul>
1032
Daniel Veillardd5f97f82000-09-17 16:38:14 +00001033<h3>2.2.1: July 21 2000</h3>
Daniel Veillarda2679fa2000-07-22 02:38:15 +00001034<ul>
1035 <li>a purely bug fixes release</li>
1036 <li>fixed an encoding support problem when parsing from a memory block</li>
1037 <li>fixed a DOCTYPE parsing problem</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +00001038 <li>removed a bug in the function allowing to override the memory
1039 allocation routines</li>
Daniel Veillarda2679fa2000-07-22 02:38:15 +00001040</ul>
1041
Daniel Veillardd5f97f82000-09-17 16:38:14 +00001042<h3>2.2.0: July 14 2000</h3>
Daniel Veillard94e90602000-07-17 14:38:19 +00001043<ul>
1044 <li>applied a lot of portability fixes</li>
1045 <li>better encoding support/cleanup and saving (content is now always
1046 encoded in UTF-8)</li>
1047 <li>the HTML parser now correctly handles encodings</li>
1048 <li>added xmlHasProp()</li>
1049 <li>fixed a serious problem with &amp;#38;</li>
1050 <li>propagated the fix to FTP client</li>
1051 <li>cleanup, bugfixes, etc ...</li>
1052 <li>Added a page about <a href="encoding.html">libxml Internationalization
1053 support</a></li>
1054</ul>
1055
Daniel Veillard60979bd2000-07-10 12:17:33 +00001056<h3>1.8.9: July 9 2000</h3>
1057<ul>
1058 <li>fixed the spec the RPMs should be better</li>
1059 <li>fixed a serious bug in the FTP implementation, released 1.8.9 to solve
1060 rpmfind users problem</li>
1061</ul>
1062
Daniel Veillard6388e172000-07-03 16:07:19 +00001063<h3>2.1.1: July 1 2000</h3>
1064<ul>
1065 <li>fixes a couple of bugs in the 2.1.0 packaging</li>
1066 <li>improvements on the HTML parser</li>
1067</ul>
1068
Daniel Veillard3f6f7f62000-06-30 17:58:25 +00001069<h3>2.1.0 and 1.8.8: June 29 2000</h3>
1070<ul>
1071 <li>1.8.8 is mostly a comodity package for upgrading to libxml2 accoding to
1072 <a href="upgrade.html">new instructions</a>. It fixes a nasty problem
1073 about &amp;#38; charref parsing</li>
1074 <li>2.1.0 also ease the upgrade from libxml v1 to the recent version. it
1075 also contains numerous fixes and enhancements:
1076 <ul>
1077 <li>added xmlStopParser() to stop parsing</li>
1078 <li>improved a lot parsing speed when there is large CDATA blocs</li>
1079 <li>includes XPath patches provided by Picdar Technology</li>
1080 <li>tried to fix as much as possible DtD validation and namespace
1081 related problems</li>
1082 <li>output to a given encoding has been added/tested</li>
1083 <li>lot of various fixes</li>
1084 </ul>
1085 </li>
1086</ul>
1087
Daniel Veillarde0aed302000-04-16 08:52:20 +00001088<h3>2.0.0: Apr 12 2000</h3>
Daniel Veillard361d8452000-04-03 19:48:13 +00001089<ul>
1090 <li>First public release of libxml2. If you are using libxml, it's a good
Daniel Veillarde0aed302000-04-16 08:52:20 +00001091 idea to check the 1.x to 2.x upgrade instructions. NOTE: while initally
1092 scheduled for Apr 3 the relase occured only on Apr 12 due to massive
1093 workload.</li>
Daniel Veillard361d8452000-04-03 19:48:13 +00001094 <li>The include are now located under $prefix/include/libxml (instead of
Daniel Veillarde0aed302000-04-16 08:52:20 +00001095 $prefix/include/gnome-xml), they also are referenced by
Daniel Veillard60979bd2000-07-10 12:17:33 +00001096 <pre>#include &lt;libxml/xxx.h&gt;</pre>
Daniel Veillarde0aed302000-04-16 08:52:20 +00001097 <p>instead of</p>
Daniel Veillard361d8452000-04-03 19:48:13 +00001098 <pre>#include "xxx.h"</pre>
1099 </li>
Daniel Veillard8f621982000-03-20 13:07:15 +00001100 <li>a new URI module for parsing URIs and following strictly RFC 2396</li>
1101 <li>the memory allocation routines used by libxml can now be overloaded
1102 dynamically by using xmlMemSetup()</li>
Daniel Veillard361d8452000-04-03 19:48:13 +00001103 <li>The previously CVS only tool tester has been renamed
1104 <strong>xmllint</strong> and is now installed as part of the libxml2
1105 package</li>
Daniel Veillarde0aed302000-04-16 08:52:20 +00001106 <li>The I/O interface has been revamped. There is now ways to plug in
1107 specific I/O modules, either at the URI scheme detection level using
1108 xmlRegisterInputCallbacks() or by passing I/O functions when creating a
1109 parser context using xmlCreateIOParserCtxt()</li>
1110 <li>there is a C preprocessor macro LIBXML_VERSION providing the version
1111 number of the libxml module in use</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +00001112 <li>a number of optional features of libxml can now be excluded at
1113 configure time (FTP/HTTP/HTML/XPath/Debug)</li>
Daniel Veillardedfb29b2000-03-14 19:59:05 +00001114</ul>
1115
1116<h3>2.0.0beta: Mar 14 2000</h3>
1117<ul>
1118 <li>This is a first Beta release of libxml version 2</li>
Daniel Veillarde356c282001-03-10 12:32:04 +00001119 <li>It's available only from<a href="ftp://xmlsoft.org/">xmlsoft.org
1120 FTP</a>, it's packaged as libxml2-2.0.0beta and available as tar and
1121 RPMs</li>
Daniel Veillardedfb29b2000-03-14 19:59:05 +00001122 <li>This version is now the head in the Gnome CVS base, the old one is
1123 available under the tag LIB_XML_1_X</li>
1124 <li>This includes a very large set of changes. Froma programmatic point of
1125 view applications should not have to be modified too much, check the <a
1126 href="upgrade.html">upgrade page</a></li>
1127 <li>Some interfaces may changes (especially a bit about encoding).</li>
1128 <li>the updates includes:
Daniel Veillard6c8b1172000-03-01 00:40:41 +00001129 <ul>
Daniel Veillardedfb29b2000-03-14 19:59:05 +00001130 <li>fix I18N support. ISO-Latin-x/UTF-8/UTF-16 (nearly) seems correctly
1131 handled now</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +00001132 <li>Better handling of entities, especially well formedness checking
1133 and proper PEref extensions in external subsets</li>
Daniel Veillard6c8b1172000-03-01 00:40:41 +00001134 <li>DTD conditional sections</li>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +00001135 <li>Validation now correcly handle entities content</li>
Daniel Veillard6c8b1172000-03-01 00:40:41 +00001136 <li><a href="http://rpmfind.net/tools/gdome/messages/0039.html">change
1137 structures to accomodate DOM</a></li>
Daniel Veillard6c8b1172000-03-01 00:40:41 +00001138 </ul>
1139 </li>
Daniel Veillardedfb29b2000-03-14 19:59:05 +00001140 <li>Serious progress were made toward compliance, <a
1141 href="conf/result.html">here are the result of the test</a> against the
1142 OASIS testsuite (except the japanese tests since I don't support that
1143 encoding yet). This URL is rebuilt every couple of hours using the CVS
1144 head version.</li>
Daniel Veillarde41f2b72000-01-30 20:00:07 +00001145</ul>
1146
Daniel Veillardf13e1ed2000-03-06 07:41:49 +00001147<h3>1.8.7: Mar 6 2000</h3>
1148<ul>
1149 <li>This is a bug fix release:</li>
1150 <li>It is possible to disable the ignorable blanks heuristic used by
1151 libxml-1.x, a new function xmlKeepBlanksDefault(0) will allow this. Note
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +00001152 that for adherence to XML spec, this behaviour will be disabled by
1153 default in 2.x . The same function will allow to keep compatibility for
1154 old code.</li>
Daniel Veillard60979bd2000-07-10 12:17:33 +00001155 <li>Blanks in &lt;a&gt; &lt;/a&gt; constructs are not ignored anymore,
1156 avoiding heuristic is really the Right Way :-\</li>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +00001157 <li>The unchecked use of snprintf which was breaking libxml-1.8.6
1158 compilation on some platforms has been fixed</li>
1159 <li>nanoftp.c nanohttp.c: Fixed '#' and '?' stripping when processing
1160 URIs</li>
1161</ul>
1162
Daniel Veillarde41f2b72000-01-30 20:00:07 +00001163<h3>1.8.6: Jan 31 2000</h3>
1164<ul>
1165 <li>added a nanoFTP transport module, debugged until the new version of <a
1166 href="http://rpmfind.net/linux/rpm2html/rpmfind.html">rpmfind</a> can use
1167 it without troubles</li>
Daniel Veillardda07c342000-01-25 18:31:22 +00001168</ul>
1169
1170<h3>1.8.5: Jan 21 2000</h3>
1171<ul>
Daniel Veillard0142b842000-01-14 14:45:24 +00001172 <li>adding APIs to parse a well balanced chunk of XML (production <a
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +00001173 href="http://www.w3.org/TR/REC-xml#NT-content">[43] content</a> of the
1174 XML spec)</li>
Daniel Veillard461a66c2000-01-18 18:01:01 +00001175 <li>fixed a hideous bug in xmlGetProp pointed by Rune.Djurhuus@fast.no</li>
Daniel Veillard60979bd2000-07-10 12:17:33 +00001176 <li>Jody Goldberg &lt;jgoldberg@home.com&gt; provided another patch trying
1177 to solve the zlib checks problems</li>
Daniel Veillard461a66c2000-01-18 18:01:01 +00001178 <li>The current state in gnome CVS base is expected to ship as 1.8.5 with
1179 gnumeric soon</li>
Daniel Veillard0142b842000-01-14 14:45:24 +00001180</ul>
1181
1182<h3>1.8.4: Jan 13 2000</h3>
1183<ul>
1184 <li>bug fixes, reintroduced xmlNewGlobalNs(), fixed xmlNewNs()</li>
1185 <li>all exit() call should have been removed from libxml</li>
1186 <li>fixed a problem with INCLUDE_WINSOCK on WIN32 platform</li>
1187 <li>added newDocFragment()</li>
Daniel Veillardf84f71f2000-01-05 19:54:23 +00001188</ul>
1189
1190<h3>1.8.3: Jan 5 2000</h3>
1191<ul>
1192 <li>a Push interface for the XML and HTML parsers</li>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +00001193 <li>a shell-like interface to the document tree (try tester --shell :-)</li>
Daniel Veillarddbfd6411999-12-28 16:35:14 +00001194 <li>lots of bug fixes and improvement added over XMas hollidays</li>
Daniel Veillard437b87b2000-01-03 17:30:46 +00001195 <li>fixed the DTD parsing code to work with the xhtml DTD</li>
Daniel Veillardf84f71f2000-01-05 19:54:23 +00001196 <li>added xmlRemoveProp(), xmlRemoveID() and xmlRemoveRef()</li>
1197 <li>Fixed bugs in xmlNewNs()</li>
Daniel Veillard437b87b2000-01-03 17:30:46 +00001198 <li>External entity loading code has been revamped, now it uses
Daniel Veillardf84f71f2000-01-05 19:54:23 +00001199 xmlLoadExternalEntity(), some fix on entities processing were added</li>
Daniel Veillard437b87b2000-01-03 17:30:46 +00001200 <li>cleaned up WIN32 includes of socket stuff</li>
Daniel Veillard5cb5ab81999-12-21 15:35:29 +00001201</ul>
1202
1203<h3>1.8.2: Dec 21 1999</h3>
1204<ul>
Daniel Veillardb24054a1999-12-18 15:32:46 +00001205 <li>I got another problem with includes and C++, I hope this issue is fixed
1206 for good this time</li>
Daniel Veillard5cb5ab81999-12-21 15:35:29 +00001207 <li>Added a few tree modification functions: xmlReplaceNode,
1208 xmlAddPrevSibling, xmlAddNextSibling, xmlNodeSetName and
1209 xmlDocSetRootElement</li>
1210 <li>Tried to improve the HTML output with help from <a
1211 href="mailto:clahey@umich.edu">Chris Lahey</a></li>
Daniel Veillarde4e51311999-12-18 15:32:46 +00001212</ul>
Daniel Veillardb24054a1999-12-18 15:32:46 +00001213
Daniel Veillarde4e51311999-12-18 15:32:46 +00001214<h3>1.8.1: Dec 18 1999</h3>
1215<ul>
1216 <li>various patches to avoid troubles when using libxml with C++ compilers
1217 the "namespace" keyword and C escaping in include files</li>
1218 <li>a problem in one of the core macros IS_CHAR was corrected</li>
1219 <li>fixed a bug introduced in 1.8.0 breaking default namespace processing,
1220 and more specifically the Dia application</li>
Daniel Veillard944b5ff1999-12-15 19:08:24 +00001221 <li>fixed a posteriori validation (validation after parsing, or by using a
1222 Dtd not specified in the original document)</li>
Daniel Veillardb24054a1999-12-18 15:32:46 +00001223 <li>fixed a bug in</li>
Daniel Veillard10a2c651999-12-12 13:03:50 +00001224</ul>
1225
1226<h3>1.8.0: Dec 12 1999</h3>
1227<ul>
1228 <li>cleanup, especially memory wise</li>
1229 <li>the parser should be more reliable, especially the HTML one, it should
1230 not crash, whatever the input !</li>
1231 <li>Integrated various patches, especially a speedup improvement for large
1232 dataset from <a href="mailto:cnygard@bellatlantic.net">Carl Nygard</a>,
1233 configure with --with-buffers to enable them.</li>
1234 <li>attribute normalization, oops should have been added long ago !</li>
1235 <li>attributes defaulted from Dtds should be available, xmlSetProp() now
1236 does entities escapting by default.</li>
Daniel Veillard4c3a2031999-11-19 17:46:26 +00001237</ul>
Daniel Veillard35008381999-10-25 13:15:52 +00001238
1239<h3>1.7.4: Oct 25 1999</h3>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +00001240<ul>
Daniel Veillard35008381999-10-25 13:15:52 +00001241 <li>Lots of HTML improvement</li>
1242 <li>Fixed some errors when saving both XML and HTML</li>
1243 <li>More examples, the regression tests should now look clean</li>
1244 <li>Fixed a bug with contiguous charref</li>
1245</ul>
1246
1247<h3>1.7.3: Sep 29 1999</h3>
1248<ul>
1249 <li>portability problems fixed</li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +00001250 <li>snprintf was used unconditionnally, leading to link problems on system
Daniel Veillard35008381999-10-25 13:15:52 +00001251 were it's not available, fixed</li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +00001252</ul>
1253
1254<h3>1.7.1: Sep 24 1999</h3>
1255<ul>
1256 <li>The basic type for strings manipulated by libxml has been renamed in
1257 1.7.1 from <strong>CHAR</strong> to <strong>xmlChar</strong>. The reason
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +00001258 is that CHAR was conflicting with a predefined type on Windows. However
1259 on non WIN32 environment, compatibility is provided by the way of a
Daniel Veillard2f4dfc41999-09-24 14:03:48 +00001260 <strong>#define </strong>.</li>
1261 <li>Changed another error : the use of a structure field called errno, and
1262 leading to troubles on platforms where it's a macro</li>
1263</ul>
1264
1265<h3>1.7.0: sep 23 1999</h3>
1266<ul>
1267 <li>Added the ability to fetch remote DTD or parsed entities, see the <a
Daniel Veillard9cb5ff42001-01-29 08:22:21 +00001268 href="html/libxml-nanohttp.html">nanohttp</a> module.</li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +00001269 <li>Added an errno to report errors by another mean than a simple printf
1270 like callback</li>
1271 <li>Finished ID/IDREF support and checking when validation</li>
1272 <li>Serious memory leaks fixed (there is now a <a
Daniel Veillard9cb5ff42001-01-29 08:22:21 +00001273 href="html/libxml-xmlmemory.html">memory wrapper</a> module)</li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +00001274 <li>Improvement of <a href="http://www.w3.org/TR/xpath">XPath</a>
1275 implementation</li>
1276 <li>Added an HTML parser front-end</li>
1277</ul>
1278
1279<h2><a name="XML">XML</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00001280
Daniel Veillard402e8c82000-02-29 22:57:47 +00001281<p><a href="http://www.w3.org/TR/REC-xml">XML is a standard</a> for
Daniel Veillardf13e1ed2000-03-06 07:41:49 +00001282markup-based structured documents. Here is <a name="example">an example XML
1283document</a>:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +00001284<pre>&lt;?xml version="1.0"?&gt;
1285&lt;EXAMPLE prop1="gnome is great" prop2="&amp;amp; linux too"&gt;
1286 &lt;head&gt;
1287 &lt;title&gt;Welcome to Gnome&lt;/title&gt;
1288 &lt;/head&gt;
1289 &lt;chapter&gt;
1290 &lt;title&gt;The Linux adventure&lt;/title&gt;
1291 &lt;p&gt;bla bla bla ...&lt;/p&gt;
1292 &lt;image href="linus.gif"/&gt;
1293 &lt;p&gt;...&lt;/p&gt;
1294 &lt;/chapter&gt;
1295&lt;/EXAMPLE&gt;</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +00001296
Daniel Veillard402e8c82000-02-29 22:57:47 +00001297<p>The first line specifies that it's an XML document and gives useful
1298information about its encoding. Then the document is a text format whose
1299structure is specified by tags between brackets. <strong>Each tag opened has
Daniel Veillardf13e1ed2000-03-06 07:41:49 +00001300to be closed</strong>. XML is pedantic about this. However, if a tag is empty
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +00001301(no content), a single tag can serve as both the opening and closing tag if
1302it ends with <code>/&gt;</code> rather than with <code>&gt;</code>. Note
1303that, for example, the image tag has no content (just an attribute) and is
1304closed by ending the tag with <code>/&gt;</code>.</p>
Daniel Veillardccb09631998-10-27 06:21:04 +00001305
Daniel Veillard402e8c82000-02-29 22:57:47 +00001306<p>XML can be applied sucessfully to a wide range of uses, from long term
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +00001307structured document maintenance (where it follows the steps of SGML) to
1308simple data encoding mechanisms like configuration file formatting (glade),
Daniel Veillardf13e1ed2000-03-06 07:41:49 +00001309spreadsheets (gnumeric), or even shorter lived documents such as WebDAV where
1310it is used to encode remote calls between a client and a server.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00001311
Daniel Veillard82687162001-01-22 15:32:01 +00001312<h2><a name="XSLT">XSLT</a></h2>
1313
Daniel Veillard6e6a6cc2001-02-15 15:55:44 +00001314<p>Check <a href="http://xmlsoft.org/XSLT">the separate libxslt page</a></p>
1315
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +00001316<p><a href="http://www.w3.org/TR/xslt">XSL Transformations</a>, is a
1317language for transforming XML documents into other XML documents (or
1318HTML/textual output).</p>
Daniel Veillard82687162001-01-22 15:32:01 +00001319
1320<p>A separate library called libxslt is being built on top of libxml2. This
1321module "libxslt" can be found in the Gnome CVS base too.</p>
1322
Daniel Veillard383b1472001-01-23 11:39:52 +00001323<p>You can check the <a
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +00001324href="http://cvs.gnome.org/lxr/source/libxslt/FEATURES">features</a>
1325supported and the progresses on the <a
Daniel Veillard6dbcaf82002-02-20 14:37:47 +00001326href="http://cvs.gnome.org/lxr/source/libxslt/ChangeLog"
1327name="Changelog">Changelog</a></p>
1328
1329<h2><a name="Python">Python and bindings</a></h2>
1330
1331<p>There is a number of language bindings and wrappers available for libxml2,
1332the list below is not exhaustive. Please contact the <a
1333href="http://mail.gnome.org/mailman/listinfo/xml-bindings">xml-bindings@gnome.org</a>
1334(<a href="http://mail.gnome.org/archives/xml-bindings/">archives</a>) in
1335order to get updates to this list or to discuss the specific topic of libxml2
1336or libxslt wrappers or bindings:</p>
1337<ul>
Daniel Veillardaf43f632002-03-08 15:05:20 +00001338 <li><a href="mailto:ari@lusis.org">Ari Johnson</a> provides a C++ wrapper
1339 for libxml:<br>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +00001340 Website: <a
1341 href="http://lusis.org/~ari/xml++/">http://lusis.org/~ari/xml++/</a><br>
1342 Download: <a
1343 href="http://lusis.org/~ari/xml++/libxml++.tar.gz">http://lusis.org/~ari/xml++/libxml++.tar.gz</a></li>
1344 <li>There is another <a href="http://libgdome-cpp.berlios.de/">C++ wrapper
1345 based on the gdome2 </a>bindings maintained by Tobias Peters.</li>
1346 <li><a
1347 href="http://mail.gnome.org/archives/xml/2001-March/msg00014.html">Matt
Daniel Veillardaf43f632002-03-08 15:05:20 +00001348 Sergeant</a> developped <a
1349 href="http://axkit.org/download/">XML::LibXSLT</a>, a perl wrapper for
1350 libxml2/libxslt as part of the <a href="http://axkit.com/">AxKit XML
1351 application server</a></li>
1352 <li><a href="mailto:dkuhlman@cutter.rexx.com">Dave Kuhlman</a> provides and
1353 earlier version of the libxml/libxslt <a
Daniel Veillard6dbcaf82002-02-20 14:37:47 +00001354 href="http://www.rexx.com/~dkuhlman">wrappers for Python</a></li>
1355 <li>Petr Kozelka provides <a
1356 href="http://sourceforge.net/projects/libxml2-pas">Pascal units to glue
1357 libxml2</a> with Kylix, Delphi and other Pascal compilers</li>
1358 <li>Wai-Sun "Squidster" Chia provides <a
1359 href="http://www.rubycolor.org/arc/redist/">bindings for Ruby</a> and
1360 libxml2 bindings are also available in Ruby through the <a
1361 href="http://libgdome-ruby.berlios.de/">libgdome-ruby</a> module
1362 maintained by Tobias Peters.</li>
Daniel Veillardaf43f632002-03-08 15:05:20 +00001363 <li>Steve Ball and contributors maintains <a
1364 href="http://tclxml.sourceforge.net/">libxml2 and libxslt bindings for
1365 Tcl</a></li>
1366 <li>There is support for libxml2 in the DOM module of PHP.</li>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +00001367</ul>
1368
1369<p>The distribution includes a set of Python bindings, which are garanteed to
1370be maintained as part of the library in the future, though the Python
Daniel Veillard0b79dfe2002-02-23 13:02:31 +00001371interface have not yet reached the maturity of the C API.</p>
Daniel Veillardaf43f632002-03-08 15:05:20 +00001372
1373<p>To install the Python bindings there are 2 options:</p>
Daniel Veillard0b79dfe2002-02-23 13:02:31 +00001374<ul>
Daniel Veillardaf43f632002-03-08 15:05:20 +00001375 <li>If you use an RPM based distribution, simply install the <a
1376 href="http://rpmfind.net/linux/rpm2html/search.php?query=libxml2-python">libxml2-python
1377 RPM</a> (and if needed the <a
1378 href="http://rpmfind.net/linux/rpm2html/search.php?query=libxslt-python">libxslt-python
1379 RPM</a>).</li>
1380 <li>Otherwise use the <a href="ftp://xmlsoft.org/python/">libxml2-python
1381 module distribution</a> corresponding to your installed version of
1382 libxml2 and libxslt. Note that to install it you will need both libxml2
1383 and libxslt installed and run "python setup.py build install" in the
1384 module tree.</li>
Daniel Veillard0b79dfe2002-02-23 13:02:31 +00001385</ul>
Daniel Veillardaf43f632002-03-08 15:05:20 +00001386
1387<p>The distribution includes a set of examples and regression tests for the
1388python bindings in the <code>python/tests</code> directory. Here are some
1389excepts from those tests:</p>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +00001390
1391<h3>tst.py:</h3>
1392
1393<p>This is a basic test of the file interface and DOM navigation:</p>
1394<pre>import libxml2
1395
1396doc = libxml2.parseFile("tst.xml")
1397if doc.name != "tst.xml":
1398 print "doc.name failed"
1399 sys.exit(1)
1400root = doc.children
1401if root.name != "doc":
1402 print "root.name failed"
1403 sys.exit(1)
1404child = root.children
1405if child.name != "foo":
1406 print "child.name failed"
1407 sys.exit(1)
1408doc.freeDoc()</pre>
1409
1410<p>The Python module is called libxml2, parseFile is the equivalent of
1411xmlParseFile (most of the bindings are automatically generated, and the xml
1412prefix is removed and the casing convention are kept). All node seen at the
1413binding level share the same subset of accesors:</p>
1414<ul>
Daniel Veillardaf43f632002-03-08 15:05:20 +00001415 <li><code>name</code> : returns the node name</li>
1416 <li><code>type</code> : returns a string indicating the node
1417 typ<code>e</code></li>
1418 <li><code>content</code> : returns the content of the node, it is based on
1419 xmlNodeGetContent() and hence is recursive.</li>
1420 <li><code>parent</code> , <code>children</code>, <code>last</code>,
1421 <code>next</code>, <code>prev</code>, <code>doc</code>,
1422 <code>properties</code>: pointing to the associated element in the tree,
1423 those may return None in case no such link exists.</li>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +00001424</ul>
1425
1426<p>Also note the need to explicitely deallocate documents with freeDoc() .
1427Reference counting for libxml2 trees would need quite a lot of work to
1428function properly, and rather than risk memory leaks if not implemented
1429correctly it sounds safer to have an explicit function to free a tree. The
1430wrapper python objects like doc, root or child are them automatically garbage
1431collected.</p>
1432
1433<h3>validate.py:</h3>
1434
1435<p>This test check the validation interfaces and redirection of error
1436messages:</p>
1437<pre>import libxml2
1438
1439#desactivate error messages from the validation
1440def noerr(ctx, str):
1441 pass
1442
1443libxml2.registerErrorHandler(noerr, None)
1444
1445ctxt = libxml2.createFileParserCtxt("invalid.xml")
1446ctxt.validate(1)
1447ctxt.parseDocument()
1448doc = ctxt.doc()
1449valid = ctxt.isValid()
1450doc.freeDoc()
1451if valid != 0:
1452 print "validity chec failed"</pre>
1453
1454<p>The first thing to notice is the call to registerErrorHandler(), it
1455defines a new error handler global to the library. It is used to avoid seeing
1456the error messages when trying to validate the invalid document.</p>
1457
1458<p>The main interest of that test is the creation of a parser context with
1459createFileParserCtxt() and how the behaviour can be changed before calling
1460parseDocument() . Similary the informations resulting from the parsing phase
1461are also available using context methods.</p>
1462
1463<p>Contexts like nodes are defined as class and the libxml2 wrappers maps the
1464C function interfaces in terms of objects method as much as possible. The
1465best to get a complete view of what methods are supported is to look at the
1466libxml2.py module containing all the wrappers.</p>
1467
1468<h3>push.py:</h3>
1469
1470<p>This test show how to activate the push parser interface:</p>
1471<pre>import libxml2
1472
1473ctxt = libxml2.createPushParser(None, "&lt;foo", 4, "test.xml")
1474ctxt.parseChunk("/&gt;", 2, 1)
1475doc = ctxt.doc()
1476
1477doc.freeDoc()</pre>
1478
1479<p>The context is created with a speciall call based on the
1480xmlCreatePushParser() from the C library. The first argument is an optional
1481SAX callback object, then the initial set of data, the lenght and the name of
1482the resource in case URI-References need to be computed by the parser.</p>
1483
1484<p>Then the data are pushed using the parseChunk() method, the last call
1485setting the thrird argument terminate to 1.</p>
1486
1487<h3>pushSAX.py:</h3>
1488
1489<p>this test show the use of the event based parsing interfaces. In this case
1490the parser does not build a document, but provides callback information as
1491the parser makes progresses analyzing the data being provided:</p>
1492<pre>import libxml2
1493log = ""
1494
1495class callback:
1496 def startDocument(self):
1497 global log
1498 log = log + "startDocument:"
1499
1500 def endDocument(self):
1501 global log
1502 log = log + "endDocument:"
1503
1504 def startElement(self, tag, attrs):
1505 global log
1506 log = log + "startElement %s %s:" % (tag, attrs)
1507
1508 def endElement(self, tag):
1509 global log
1510 log = log + "endElement %s:" % (tag)
1511
1512 def characters(self, data):
1513 global log
1514 log = log + "characters: %s:" % (data)
1515
1516 def warning(self, msg):
1517 global log
1518 log = log + "warning: %s:" % (msg)
1519
1520 def error(self, msg):
1521 global log
1522 log = log + "error: %s:" % (msg)
1523
1524 def fatalError(self, msg):
1525 global log
1526 log = log + "fatalError: %s:" % (msg)
1527
1528handler = callback()
1529
1530ctxt = libxml2.createPushParser(handler, "&lt;foo", 4, "test.xml")
1531chunk = " url='tst'&gt;b"
1532ctxt.parseChunk(chunk, len(chunk), 0)
1533chunk = "ar&lt;/foo&gt;"
1534ctxt.parseChunk(chunk, len(chunk), 1)
1535
Daniel Veillardfcbfa2d2002-02-21 17:54:27 +00001536reference = "startDocument:startElement foo {'url': 'tst'}:" + \
1537 "characters: bar:endElement foo:endDocument:"
Daniel Veillard6dbcaf82002-02-20 14:37:47 +00001538if log != reference:
1539 print "Error got: %s" % log
1540 print "Exprected: %s" % reference</pre>
1541
1542<p>The key object in that test is the handler, it provides a number of entry
1543points which can be called by the parser as it makes progresses to indicate
1544the information set obtained. The full set of callback is larger than what
1545the callback class in that specific example implements (see the SAX
1546definition for a complete list). The wrapper will only call those supplied by
1547the object when activated. The startElement receives the names of the element
1548and a dictionnary containing the attributes carried by this element.</p>
1549
1550<p>Also note that the reference string generated from the callback shows a
1551single character call even though the string "bar" is passed to the parser
1552from 2 different call to parseChunk()</p>
1553
1554<h3>xpath.py:</h3>
1555
1556<p>This is a basic test of XPath warppers support</p>
1557<pre>import libxml2
1558
1559doc = libxml2.parseFile("tst.xml")
1560ctxt = doc.xpathNewContext()
1561res = ctxt.xpathEval("//*")
1562if len(res) != 2:
1563 print "xpath query: wrong node set size"
1564 sys.exit(1)
1565if res[0].name != "doc" or res[1].name != "foo":
1566 print "xpath query: wrong node set value"
1567 sys.exit(1)
1568doc.freeDoc()
1569ctxt.xpathFreeContext()</pre>
1570
1571<p>This test parses a file, then create an XPath context to evaluate XPath
1572expression on it. The xpathEval() method execute an XPath query and returns
1573the result mapped in a Python way. String and numbers are natively converted,
1574and node sets are returned as a tuple of libxml2 Python nodes wrappers. Like
1575the document, the XPath context need to be freed explicitely, also not that
1576the result of the XPath query may point back to the document tree and hence
1577the document must be freed after the result of the query is used.</p>
1578
1579<h3>xpathext.py:</h3>
1580
1581<p>This test shows how to extend the XPath engine with functions written in
1582python:</p>
1583<pre>import libxml2
1584
1585def foo(ctx, x):
1586 return x + 1
1587
1588doc = libxml2.parseFile("tst.xml")
1589ctxt = doc.xpathNewContext()
1590libxml2.registerXPathFunction(ctxt._o, "foo", None, foo)
1591res = ctxt.xpathEval("foo(1)")
1592if res != 2:
1593 print "xpath extension failure"
1594doc.freeDoc()
1595ctxt.xpathFreeContext()</pre>
1596
1597<p>Note how the extension function is registered with the context (but that
1598part is not yet finalized, ths may change slightly in the future).</p>
1599
1600<h3>tstxpath.py:</h3>
1601
1602<p>This test is similar to the previousone but shows how the extension
1603function can access the XPath evaluation context:</p>
1604<pre>def foo(ctx, x):
1605 global called
1606
1607 #
1608 # test that access to the XPath evaluation contexts
1609 #
1610 pctxt = libxml2.xpathParserContext(_obj=ctx)
1611 ctxt = pctxt.context()
1612 called = ctxt.function()
1613 return x + 1</pre>
1614
1615<p>All the interfaces around the XPath parser(or rather evaluation) context
1616are not finalized, but it should be sufficient to do contextual work at the
1617evaluation point.</p>
1618
1619<h3>Memory debugging:</h3>
1620
1621<p>last but not least, all tests starts with the following prologue:</p>
1622<pre>#memory debug specific
Daniel Veillardaf43f632002-03-08 15:05:20 +00001623libxml2.debugMemory(1)</pre>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +00001624
1625<p>and ends with the following epilogue:</p>
1626<pre>#memory debug specific
1627libxml2.cleanupParser()
1628if libxml2.debugMemory(1) == 0:
1629 print "OK"
1630else:
1631 print "Memory leak %d bytes" % (libxml2.debugMemory(1))
1632 libxml2.dumpMemory()</pre>
1633
1634<p>Those activate the memory debugging interface of libxml2 where all
1635alloacted block in the library are tracked. The prologue then cleans up the
1636library state and checks that all allocated memory has been freed. If not it
1637calls dumpMemory() which saves that list in a <code>.memdump</code> file.</p>
Daniel Veillard82687162001-01-22 15:32:01 +00001638
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00001639<h2><a name="architecture">libxml architecture</a></h2>
Daniel Veillard4540be42000-08-19 16:40:28 +00001640
Daniel Veillardec70e912001-02-26 20:10:45 +00001641<p>Libxml is made of multiple components; some of them are optional, and most
1642of the block interfaces are public. The main components are:</p>
Daniel Veillard4540be42000-08-19 16:40:28 +00001643<ul>
1644 <li>an Input/Output layer</li>
Daniel Veillard91e9d582001-02-26 07:31:12 +00001645 <li>FTP and HTTP client layers (optional)</li>
Daniel Veillard4540be42000-08-19 16:40:28 +00001646 <li>an Internationalization layer managing the encodings support</li>
Daniel Veillard91e9d582001-02-26 07:31:12 +00001647 <li>a URI module</li>
Daniel Veillard4540be42000-08-19 16:40:28 +00001648 <li>the XML parser and its basic SAX interface</li>
Daniel Veillard91e9d582001-02-26 07:31:12 +00001649 <li>an HTML parser using the same SAX interface (optional)</li>
Daniel Veillard4540be42000-08-19 16:40:28 +00001650 <li>a SAX tree module to build an in-memory DOM representation</li>
1651 <li>a tree module to manipulate the DOM representation</li>
Daniel Veillard91e9d582001-02-26 07:31:12 +00001652 <li>a validation module using the DOM representation (optional)</li>
Daniel Veillard4540be42000-08-19 16:40:28 +00001653 <li>an XPath module for global lookup in a DOM representation
Daniel Veillard91e9d582001-02-26 07:31:12 +00001654 (optional)</li>
1655 <li>a debug module (optional)</li>
Daniel Veillard4540be42000-08-19 16:40:28 +00001656</ul>
1657
1658<p>Graphically this gives the following:</p>
1659
1660<p><img src="libxml.gif" alt="a graphical view of the various"></p>
1661
1662<p></p>
1663
Daniel Veillard2f4dfc41999-09-24 14:03:48 +00001664<h2><a name="tree">The tree output</a></h2>
Daniel Veillardb05deb71999-08-10 19:04:08 +00001665
1666<p>The parser returns a tree built during the document analysis. The value
Daniel Veillard402e8c82000-02-29 22:57:47 +00001667returned is an <strong>xmlDocPtr</strong> (i.e., a pointer to an
Daniel Veillardf13e1ed2000-03-06 07:41:49 +00001668<strong>xmlDoc</strong> structure). This structure contains information such
Daniel Veillard306be992000-07-03 12:38:45 +00001669as the file name, the document type, and a <strong>children</strong> pointer
1670which is the root of the document (or more exactly the first child under the
1671root which is the document). The tree is made of <strong>xmlNode</strong>s,
Daniel Veillard91e9d582001-02-26 07:31:12 +00001672chained in double-linked lists of siblings and with a children&lt;-&gt;parent
Daniel Veillard306be992000-07-03 12:38:45 +00001673relationship. An xmlNode can also carry properties (a chain of xmlAttr
1674structures). An attribute may have a value which is a list of TEXT or
1675ENTITY_REF nodes.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +00001676
Daniel Veillard88f00ae2000-03-02 00:15:55 +00001677<p>Here is an example (erroneous with respect to the XML spec since there
1678should be only one ELEMENT under the root):</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +00001679
1680<p><img src="structure.gif" alt=" structure.gif "></p>
1681
1682<p>In the source package there is a small program (not installed by default)
Daniel Veillard361d8452000-04-03 19:48:13 +00001683called <strong>xmllint</strong> which parses XML files given as argument and
Daniel Veillardf13e1ed2000-03-06 07:41:49 +00001684prints them back as parsed. This is useful for detecting errors both in XML
1685code and in the XML parser itself. It has an option <strong>--debug</strong>
Daniel Veillard91e9d582001-02-26 07:31:12 +00001686which prints the actual in-memory structure of the document; here is the
Daniel Veillardf13e1ed2000-03-06 07:41:49 +00001687result with the <a href="#example">example</a> given before:</p>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +00001688<pre>DOCUMENT
1689version=1.0
1690standalone=true
1691 ELEMENT EXAMPLE
1692 ATTRIBUTE prop1
1693 TEXT
1694 content=gnome is great
1695 ATTRIBUTE prop2
1696 ENTITY_REF
1697 TEXT
Daniel Veillard0142b842000-01-14 14:45:24 +00001698 content= linux too
Daniel Veillard402e8c82000-02-29 22:57:47 +00001699 ELEMENT head
Daniel Veillard10c6a8f1998-10-28 01:00:12 +00001700 ELEMENT title
Daniel Veillard25940b71998-10-29 05:51:30 +00001701 TEXT
1702 content=Welcome to Gnome
Daniel Veillard10c6a8f1998-10-28 01:00:12 +00001703 ELEMENT chapter
1704 ELEMENT title
Daniel Veillard25940b71998-10-29 05:51:30 +00001705 TEXT
1706 content=The Linux adventure
Daniel Veillard10c6a8f1998-10-28 01:00:12 +00001707 ELEMENT p
Daniel Veillard25940b71998-10-29 05:51:30 +00001708 TEXT
1709 content=bla bla bla ...
Daniel Veillard10c6a8f1998-10-28 01:00:12 +00001710 ELEMENT image
1711 ATTRIBUTE href
1712 TEXT
1713 content=linus.gif
1714 ELEMENT p
Daniel Veillard25940b71998-10-29 05:51:30 +00001715 TEXT
1716 content=...</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +00001717
Daniel Veillard88f00ae2000-03-02 00:15:55 +00001718<p>This should be useful for learning the internal representation model.</p>
Daniel Veillardccb09631998-10-27 06:21:04 +00001719
Daniel Veillard2f4dfc41999-09-24 14:03:48 +00001720<h2><a name="interface">The SAX interface</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00001721
Daniel Veillard402e8c82000-02-29 22:57:47 +00001722<p>Sometimes the DOM tree output is just too large to fit reasonably into
Daniel Veillard88f00ae2000-03-02 00:15:55 +00001723memory. In that case (and if you don't expect to save back the XML document
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +00001724loaded using libxml), it's better to use the SAX interface of libxml. SAX is
1725a <strong>callback-based interface</strong> to the parser. Before parsing,
1726the application layer registers a customized set of callbacks which are
1727called by the library as it progresses through the XML input.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00001728
Daniel Veillard88f00ae2000-03-02 00:15:55 +00001729<p>To get more detailed step-by-step guidance on using the SAX interface of
Daniel Veillard4540be42000-08-19 16:40:28 +00001730libxml, see the <a
1731href="http://www.daa.com.au/~james/gnome/xml-sax/xml-sax.html">nice
1732documentation</a>.written by <a href="mailto:james@daa.com.au">James
Daniel Veillard88f00ae2000-03-02 00:15:55 +00001733Henstridge</a>.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00001734
1735<p>You can debug the SAX behaviour by using the <strong>testSAX</strong>
1736program located in the gnome-xml module (it's usually not shipped in the
Daniel Veillard88f00ae2000-03-02 00:15:55 +00001737binary packages of libxml, but you can find it in the tar source
Daniel Veillard402e8c82000-02-29 22:57:47 +00001738distribution). Here is the sequence of callbacks that would be reported by
Daniel Veillard88f00ae2000-03-02 00:15:55 +00001739testSAX when parsing the example XML document shown earlier:</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00001740<pre>SAX.setDocumentLocator()
1741SAX.startDocument()
1742SAX.getEntity(amp)
1743SAX.startElement(EXAMPLE, prop1='gnome is great', prop2='&amp;amp; linux too')
1744SAX.characters( , 3)
1745SAX.startElement(head)
1746SAX.characters( , 4)
1747SAX.startElement(title)
1748SAX.characters(Welcome to Gnome, 16)
1749SAX.endElement(title)
1750SAX.characters( , 3)
1751SAX.endElement(head)
1752SAX.characters( , 3)
1753SAX.startElement(chapter)
1754SAX.characters( , 4)
1755SAX.startElement(title)
1756SAX.characters(The Linux adventure, 19)
1757SAX.endElement(title)
1758SAX.characters( , 4)
1759SAX.startElement(p)
1760SAX.characters(bla bla bla ..., 15)
1761SAX.endElement(p)
1762SAX.characters( , 4)
1763SAX.startElement(image, href='linus.gif')
1764SAX.endElement(image)
1765SAX.characters( , 4)
1766SAX.startElement(p)
1767SAX.characters(..., 3)
1768SAX.endElement(p)
1769SAX.characters( , 3)
1770SAX.endElement(chapter)
1771SAX.characters( , 1)
1772SAX.endElement(EXAMPLE)
1773SAX.endDocument()</pre>
1774
Daniel Veillardec70e912001-02-26 20:10:45 +00001775<p>Most of the other interfaces of libxml are based on the DOM tree-building
1776facility, so nearly everything up to the end of this document presupposes the
1777use of the standard DOM tree build. Note that the DOM tree itself is built by
1778a set of registered default callbacks, without internal specific
1779interface.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00001780
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00001781<h2><a name="Validation">Validation &amp; DTDs</a></h2>
1782
1783<p>Table of Content:</p>
1784<ol>
1785 <li><a href="#General5">General overview</a></li>
1786 <li><a href="#definition">The definition</a></li>
1787 <li><a href="#Simple">Simple rules</a>
1788 <ol>
Daniel Veillard9c466822001-10-25 12:03:39 +00001789 <li><a href="#reference">How to reference a DTD from a document</a></li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00001790 <li><a href="#Declaring">Declaring elements</a></li>
1791 <li><a href="#Declaring1">Declaring attributes</a></li>
1792 </ol>
1793 </li>
1794 <li><a href="#Some">Some examples</a></li>
1795 <li><a href="#validate">How to validate</a></li>
1796 <li><a href="#Other">Other resources</a></li>
1797</ol>
1798
1799<h3><a name="General5">General overview</a></h3>
1800
1801<p>Well what is validation and what is a DTD ?</p>
1802
1803<p>DTD is the acronym for Document Type Definition. This is a description of
1804the content for a familly of XML files. This is part of the XML 1.0
1805specification, and alows to describe and check that a given document instance
1806conforms to a set of rules detailing its structure and content.</p>
1807
1808<p>Validation is the process of checking a document against a DTD (more
1809generally against a set of construction rules).</p>
1810
1811<p>The validation process and building DTDs are the two most difficult parts
1812of the XML life cycle. Briefly a DTD defines all the possibles element to be
1813found within your document, what is the formal shape of your document tree
1814(by defining the allowed content of an element, either text, a regular
1815expression for the allowed list of children, or mixed content i.e. both text
1816and children). The DTD also defines the allowed attributes for all elements
1817and the types of the attributes.</p>
1818
1819<h3><a name="definition1">The definition</a></h3>
1820
1821<p>The <a href="http://www.w3.org/TR/REC-xml">W3C XML Recommendation</a> (<a
1822href="http://www.xml.com/axml/axml.html">Tim Bray's annotated version of
1823Rev1</a>):</p>
1824<ul>
1825 <li><a href="http://www.w3.org/TR/REC-xml#elemdecls">Declaring
1826 elements</a></li>
1827 <li><a href="http://www.w3.org/TR/REC-xml#attdecls">Declaring
1828 attributes</a></li>
1829</ul>
1830
1831<p>(unfortunately) all this is inherited from the SGML world, the syntax is
1832ancient...</p>
1833
1834<h3><a name="Simple1">Simple rules</a></h3>
1835
1836<p>Writing DTD can be done in multiple ways, the rules to build them if you
1837need something fixed or something which can evolve over time can be radically
1838different. Really complex DTD like Docbook ones are flexible but quite harder
1839to design. I will just focuse on DTDs for a formats with a fixed simple
1840structure. It is just a set of basic rules, and definitely not exhaustive nor
1841useable for complex DTD design.</p>
1842
1843<h4><a name="reference1">How to reference a DTD from a document</a>:</h4>
1844
1845<p>Assuming the top element of the document is <code>spec</code> and the dtd
1846is placed in the file <code>mydtd</code> in the subdirectory
1847<code>dtds</code> of the directory from where the document were loaded:</p>
1848
1849<p><code>&lt;!DOCTYPE spec SYSTEM "dtds/mydtd"&gt;</code></p>
1850
1851<p>Notes:</p>
1852<ul>
1853 <li>the system string is actually an URI-Reference (as defined in <a
1854 href="http://www.ietf.org/rfc/rfc2396.txt">RFC 2396</a>) so you can use a
1855 full URL string indicating the location of your DTD on the Web, this is a
1856 really good thing to do if you want others to validate your document</li>
1857 <li>it is also possible to associate a <code>PUBLIC</code> identifier (a
1858 magic string) so that the DTd is looked up in catalogs on the client side
1859 without having to locate it on the web</li>
1860 <li>a dtd contains a set of elements and attributes declarations, but they
1861 don't define what the root of the document should be. This is explicitely
1862 told to the parser/validator as the first element of the
1863 <code>DOCTYPE</code> declaration.</li>
1864</ul>
1865
1866<h4><a name="Declaring2">Declaring elements</a>:</h4>
1867
1868<p>The following declares an element <code>spec</code>:</p>
1869
1870<p><code>&lt;!ELEMENT spec (front, body, back?)&gt;</code></p>
1871
1872<p>it also expresses that the spec element contains one <code>front</code>,
1873one <code>body</code> and one optionnal <code>back</code> children elements
1874in this order. The declaration of one element of the structure and its
1875content are done in a single declaration. Similary the following declares
1876<code>div1</code> elements:</p>
1877
Daniel Veillard51737272002-01-23 23:10:38 +00001878<p><code>&lt;!ELEMENT div1 (head, (p | list | note)*, div2?)&gt;</code></p>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00001879
1880<p>means div1 contains one <code>head</code> then a series of optional
1881<code>p</code>, <code>list</code>s and <code>note</code>s and then an
1882optional <code>div2</code>. And last but not least an element can contain
1883text:</p>
1884
1885<p><code>&lt;!ELEMENT b (#PCDATA)&gt;</code></p>
1886
1887<p><code>b</code> contains text or being of mixed content (text and elements
1888in no particular order):</p>
1889
1890<p><code>&lt;!ELEMENT p (#PCDATA|a|ul|b|i|em)*&gt;</code></p>
1891
1892<p><code>p </code>can contain text or <code>a</code>, <code>ul</code>,
1893<code>b</code>, <code>i </code>or <code>em</code> elements in no particular
1894order.</p>
1895
1896<h4><a name="Declaring1">Declaring attributes</a>:</h4>
1897
1898<p>again the attributes declaration includes their content definition:</p>
1899
1900<p><code>&lt;!ATTLIST termdef name CDATA #IMPLIED&gt;</code></p>
1901
1902<p>means that the element <code>termdef</code> can have a <code>name</code>
1903attribute containing text (<code>CDATA</code>) and which is optionnal
1904(<code>#IMPLIED</code>). The attribute value can also be defined within a
1905set:</p>
1906
1907<p><code>&lt;!ATTLIST list type (bullets|ordered|glossary)
1908"ordered"&gt;</code></p>
1909
1910<p>means <code>list</code> element have a <code>type</code> attribute with 3
1911allowed values "bullets", "ordered" or "glossary" and which default to
1912"ordered" if the attribute is not explicitely specified.</p>
1913
1914<p>The content type of an attribute can be text (<code>CDATA</code>),
1915anchor/reference/references
1916(<code>ID</code>/<code>IDREF</code>/<code>IDREFS</code>), entity(ies)
1917(<code>ENTITY</code>/<code>ENTITIES</code>) or name(s)
1918(<code>NMTOKEN</code>/<code>NMTOKENS</code>). The following defines that a
1919<code>chapter</code> element can have an optional <code>id</code> attribute
1920of type <code>ID</code>, usable for reference from attribute of type
1921IDREF:</p>
1922
1923<p><code>&lt;!ATTLIST chapter id ID #IMPLIED&gt;</code></p>
1924
1925<p>The last value of an attribute definition can be <code>#REQUIRED
1926</code>meaning that the attribute has to be given, <code>#IMPLIED</code>
1927meaning that it is optional, or the default value (possibly prefixed by
1928<code>#FIXED</code> if it is the only allowed).</p>
1929
1930<p>Notes:</p>
1931<ul>
1932 <li>usually the attributes pertaining to a given element are declared in a
1933 single expression, but it is just a convention adopted by a lot of DTD
1934 writers:
1935 <pre>&lt;!ATTLIST termdef
1936 id ID #REQUIRED
1937 name CDATA #IMPLIED&gt;</pre>
1938 <p>The previous construct defines both <code>id</code> and
1939 <code>name</code> attributes for the element <code>termdef</code></p>
1940 </li>
1941</ul>
1942
1943<h3><a name="Some1">Some examples</a></h3>
1944
1945<p>The directory <code>test/valid/dtds/</code> in the libxml distribution
1946contains some complex DTD examples. The <code>test/valid/dia.xml</code>
1947example shows an XML file where the simple DTD is directly included within
1948the document.</p>
1949
1950<h3><a name="validate1">How to validate</a></h3>
1951
1952<p>The simplest is to use the xmllint program comming with libxml. The
1953<code>--valid</code> option turn on validation of the files given as input,
1954for example the following validates a copy of the first revision of the XML
19551.0 specification:</p>
1956
1957<p><code>xmllint --valid --noout test/valid/REC-xml-19980210.xml</code></p>
1958
1959<p>the -- noout is used to not output the resulting tree.</p>
1960
1961<p>The <code>--dtdvalid dtd</code> allows to validate the document(s) against
1962a given DTD.</p>
1963
1964<p>Libxml exports an API to handle DTDs and validation, check the <a
1965href="http://xmlsoft.org/html/libxml-valid.html">associated
1966description</a>.</p>
1967
1968<h3><a name="Other1">Other resources</a></h3>
1969
1970<p>DTDs are as old as SGML. So there may be a number of examples on-line, I
1971will just list one for now, others pointers welcome:</p>
1972<ul>
1973 <li><a href="http://www.xml101.com:8081/dtd/">XML-101 DTD</a></li>
1974</ul>
1975
1976<p>I suggest looking at the examples found under test/valid/dtd and any of
1977the large number of books available on XML. The dia example in test/valid
1978should be both simple and complete enough to allow you to build your own.</p>
1979
1980<p></p>
1981
1982<h2><a name="Memory">Memory Management</a></h2>
1983
1984<p>Table of Content:</p>
1985<ol>
1986 <li><a href="#General3">General overview</a></li>
Daniel Veillard9c466822001-10-25 12:03:39 +00001987 <li><a href="#setting">Setting libxml set of memory routines</a></li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00001988 <li><a href="#cleanup">Cleaning up after parsing</a></li>
1989 <li><a href="#Debugging">Debugging routines</a></li>
1990 <li><a href="#General4">General memory requirements</a></li>
1991</ol>
1992
1993<h3><a name="General3">General overview</a></h3>
1994
1995<p>The module <code><a
1996href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlmemory.h</a></code>
1997provides the interfaces to the libxml memory system:</p>
1998<ul>
1999 <li>libxml does not use the libc memory allocator directly but xmlFree(),
2000 xmlMalloc() and xmlRealloc()</li>
2001 <li>those routines can be reallocated to a specific set of routine, by
2002 default the libc ones i.e. free(), malloc() and realloc()</li>
2003 <li>the xmlmemory.c module includes a set of debugging routine</li>
2004</ul>
2005
2006<h3><a name="setting">Setting libxml set of memory routines</a></h3>
2007
2008<p>It is sometimes useful to not use the default memory allocator, either for
2009debugging, analysis or to implement a specific behaviour on memory management
2010(like on embedded systems). Two function calls are available to do so:</p>
2011<ul>
Daniel Veillardaf43f632002-03-08 15:05:20 +00002012 <li><a href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlMemGet
2013 ()</a> which return the current set of functions in use by the parser</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002014 <li><a
2015 href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlMemSetup()</a>
Daniel Veillardaf43f632002-03-08 15:05:20 +00002016 which allow to set up a new set of memory allocation functions</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002017</ul>
2018
2019<p>Of course a call to xmlMemSetup() should probably be done before calling
2020any other libxml routines (unless you are sure your allocations routines are
2021compatibles).</p>
2022
2023<h3><a name="cleanup">Cleaning up after parsing</a></h3>
2024
2025<p>Libxml is not stateless, there is a few set of memory structures needing
2026allocation before the parser is fully functionnal (some encoding structures
2027for example). This also mean that once parsing is finished there is a tiny
2028amount of memory (a few hundred bytes) which can be recollected if you don't
2029reuse the parser immediately:</p>
2030<ul>
2031 <li><a href="http://xmlsoft.org/html/libxml-parser.html">xmlCleanupParser
Daniel Veillardaf43f632002-03-08 15:05:20 +00002032 ()</a> is a centralized routine to free the parsing states. Note that it
2033 won't deallocate any produced tree if any (use the xmlFreeDoc() and
2034 related routines for this).</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002035 <li><a href="http://xmlsoft.org/html/libxml-parser.html">xmlInitParser
Daniel Veillardaf43f632002-03-08 15:05:20 +00002036 ()</a> is the dual routine allowing to preallocate the parsing state
2037 which can be useful for example to avoid initialization reentrancy
2038 problems when using libxml in multithreaded applications</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002039</ul>
2040
2041<p>Generally xmlCleanupParser() is safe, if needed the state will be rebuild
2042at the next invocation of parser routines, but be careful of the consequences
2043in multithreaded applications.</p>
2044
2045<h3><a name="Debugging">Debugging routines</a></h3>
2046
2047<p>When configured using --with-mem-debug flag (off by default), libxml uses
2048a set of memory allocation debugging routineskeeping track of all allocated
2049blocks and the location in the code where the routine was called. A couple of
2050other debugging routines allow to dump the memory allocated infos to a file
2051or call a specific routine when a given block number is allocated:</p>
2052<ul>
2053 <li><a
2054 href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlMallocLoc()</a>
Daniel Veillardaf43f632002-03-08 15:05:20 +00002055 <a
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002056 href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlReallocLoc()</a>
2057 and <a
2058 href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlMemStrdupLoc()</a>
2059 are the memory debugging replacement allocation routines</li>
2060 <li><a href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlMemoryDump
Daniel Veillardaf43f632002-03-08 15:05:20 +00002061 ()</a> dumps all the informations about the allocated memory block lefts
2062 in the <code>.memdump</code> file</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002063</ul>
2064
2065<p>When developping libxml memory debug is enabled, the tests programs call
2066xmlMemoryDump () and the "make test" regression tests will check for any
2067memory leak during the full regression test sequence, this helps a lot
2068ensuring that libxml does not leak memory and bullet proof memory
2069allocations use (some libc implementations are known to be far too permissive
2070resulting in major portability problems!).</p>
2071
2072<p>If the .memdump reports a leak, it displays the allocation function and
2073also tries to give some informations about the content and structure of the
2074allocated blocks left. This is sufficient in most cases to find the culprit,
2075but not always. Assuming the allocation problem is reproductible, it is
2076possible to find more easilly:</p>
2077<ol>
2078 <li>write down the block number xxxx not allocated</li>
2079 <li>export the environement variable XML_MEM_BREAKPOINT=xxxx</li>
2080 <li>run the program under a debugger and set a breakpoint on
2081 xmlMallocBreakpoint() a specific function called when this precise block
2082 is allocated</li>
2083 <li>when the breakpoint is reached you can then do a fine analysis of the
2084 allocation an step to see the condition resulting in the missing
2085 deallocation.</li>
2086</ol>
2087
2088<p>I used to use a commercial tool to debug libxml memory problems but after
2089noticing that it was not detecting memory leaks that simple mechanism was
2090used and proved extremely efficient until now.</p>
2091
2092<h3><a name="General4">General memory requirements</a></h3>
2093
2094<p>How much libxml memory require ? It's hard to tell in average it depends
2095of a number of things:</p>
2096<ul>
2097 <li>the parser itself should work in a fixed amout of memory, except for
2098 information maintained about the stacks of names and entities locations.
2099 The I/O and encoding handlers will probably account for a few KBytes.
2100 This is true for both the XML and HTML parser (though the HTML parser
2101 need more state).</li>
2102 <li>If you are generating the DOM tree then memory requirements will grow
2103 nearly lineary with the size of the data. In general for a balanced
2104 textual document the internal memory requirement is about 4 times the
2105 size of the UTF8 serialization of this document (exmple the XML-1.0
2106 recommendation is a bit more of 150KBytes and takes 650KBytes of main
2107 memory when parsed). Validation will add a amount of memory required for
2108 maintaining the external Dtd state which should be linear with the
2109 complexity of the content model defined by the Dtd</li>
2110 <li>If you don't care about the advanced features of libxml like
2111 validation, DOM, XPath or XPointer, but really need to work fixed memory
2112 requirements, then the SAX interface should be used.</li>
2113</ul>
2114
2115<p></p>
2116
2117<h2><a name="Encodings">Encodings support</a></h2>
2118
2119<p>Table of Content:</p>
2120<ol>
2121 <li><a href="encoding.html#What">What does internationalization support
2122 mean ?</a></li>
2123 <li><a href="encoding.html#internal">The internal encoding, how and
2124 why</a></li>
2125 <li><a href="encoding.html#implemente">How is it implemented ?</a></li>
2126 <li><a href="encoding.html#Default">Default supported encodings</a></li>
2127 <li><a href="encoding.html#extend">How to extend the existing
2128 support</a></li>
2129</ol>
2130
2131<h3><a name="What">What does internationalization support mean ?</a></h3>
2132
2133<p>XML was designed from the start to allow the support of any character set
2134by using Unicode. Any conformant XML parser has to support the UTF-8 and
2135UTF-16 default encodings which can both express the full unicode ranges. UTF8
2136is a variable length encoding whose greatest point are to resuse the same
2137emcoding for ASCII and to save space for Western encodings, but it is a bit
2138more complex to handle in practice. UTF-16 use 2 bytes per characters (and
2139sometimes combines two pairs), it makes implementation easier, but looks a
2140bit overkill for Western languages encoding. Moreover the XML specification
2141allows document to be encoded in other encodings at the condition that they
2142are clearly labelled as such. For example the following is a wellformed XML
2143document encoded in ISO-8859 1 and using accentuated letter that we French
2144likes for both markup and content:</p>
2145<pre>&lt;?xml version="1.0" encoding="ISO-8859-1"?&gt;
2146&lt;très&gt;là&lt;/très&gt;</pre>
2147
2148<p>Having internationalization support in libxml means the foolowing:</p>
2149<ul>
2150 <li>the document is properly parsed</li>
2151 <li>informations about it's encoding are saved</li>
2152 <li>it can be modified</li>
2153 <li>it can be saved in its original encoding</li>
2154 <li>it can also be saved in another encoding supported by libxml (for
2155 example straight UTF8 or even an ASCII form)</li>
2156</ul>
2157
2158<p>Another very important point is that the whole libxml API, with the
2159exception of a few routines to read with a specific encoding or save to a
2160specific encoding, is completely agnostic about the original encoding of the
2161document.</p>
2162
2163<p>It should be noted too that the HTML parser embedded in libxml now obbey
2164the same rules too, the following document will be (as of 2.2.2) handled in
2165an internationalized fashion by libxml too:</p>
2166<pre>&lt;!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"
2167 "http://www.w3.org/TR/REC-html40/loose.dtd"&gt;
2168&lt;html lang="fr"&gt;
2169&lt;head&gt;
2170 &lt;META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=ISO-8859-1"&gt;
2171&lt;/head&gt;
2172&lt;body&gt;
2173&lt;p&gt;W3C crée des standards pour le Web.&lt;/body&gt;
2174&lt;/html&gt;</pre>
2175
2176<h3><a name="internal">The internal encoding, how and why</a></h3>
2177
2178<p>One of the core decision was to force all documents to be converted to a
2179default internal encoding, and that encoding to be UTF-8, here are the
2180rationale for those choices:</p>
2181<ul>
2182 <li>keeping the native encoding in the internal form would force the libxml
2183 users (or the code associated) to be fully aware of the encoding of the
2184 original document, for examples when adding a text node to a document,
2185 the content would have to be provided in the document encoding, i.e. the
2186 client code would have to check it before hand, make sure it's conformant
2187 to the encoding, etc ... Very hard in practice, though in some specific
2188 cases this may make sense.</li>
2189 <li>the second decision was which encoding. From the XML spec only UTF8 and
2190 UTF16 really makes sense as being the two only encodings for which there
2191 is amndatory support. UCS-4 (32 bits fixed size encoding) could be
2192 considered an intelligent choice too since it's a direct Unicode mapping
2193 support. I selected UTF-8 on the basis of efficiency and compatibility
2194 with surrounding software:
2195 <ul>
2196 <li>UTF-8 while a bit more complex to convert from/to (i.e. slightly
2197 more costly to import and export CPU wise) is also far more compact
2198 than UTF-16 (and UCS-4) for a majority of the documents I see it used
2199 for right now (RPM RDF catalogs, advogato data, various configuration
2200 file formats, etc.) and the key point for today's computer
2201 architecture is efficient uses of caches. If one nearly double the
2202 memory requirement to store the same amount of data, this will trash
2203 caches (main memory/external caches/internal caches) and my take is
2204 that this harms the system far more than the CPU requirements needed
2205 for the conversion to UTF-8</li>
2206 <li>Most of libxml version 1 users were using it with straight ASCII
2207 most of the time, doing the conversion with an internal encoding
2208 requiring all their code to be rewritten was a serious show-stopper
2209 for using UTF-16 or UCS-4.</li>
2210 <li>UTF-8 is being used as the de-facto internal encoding standard for
2211 related code like the <a href="http://www.pango.org/">pango</a>
2212 upcoming Gnome text widget, and a lot of Unix code (yep another place
2213 where Unix programmer base takes a different approach from Microsoft
2214 - they are using UTF-16)</li>
2215 </ul>
2216 </li>
2217</ul>
2218
2219<p>What does this mean in practice for the libxml user:</p>
2220<ul>
2221 <li>xmlChar, the libxml data type is a byte, those bytes must be assembled
2222 as UTF-8 valid strings. The proper way to terminate an xmlChar * string
2223 is simply to append 0 byte, as usual.</li>
2224 <li>One just need to make sure that when using chars outside the ASCII set,
2225 the values has been properly converted to UTF-8</li>
2226</ul>
2227
2228<h3><a name="implemente">How is it implemented ?</a></h3>
2229
2230<p>Let's describe how all this works within libxml, basically the I18N
2231(internationalization) support get triggered only during I/O operation, i.e.
2232when reading a document or saving one. Let's look first at the reading
2233sequence:</p>
2234<ol>
2235 <li>when a document is processed, we usually don't know the encoding, a
2236 simple heuristic allows to detect UTF-18 and UCS-4 from whose where the
2237 ASCII range (0-0x7F) maps with ASCII</li>
2238 <li>the xml declaration if available is parsed, including the encoding
2239 declaration. At that point, if the autodetected encoding is different
2240 from the one declared a call to xmlSwitchEncoding() is issued.</li>
2241 <li>If there is no encoding declaration, then the input has to be in either
2242 UTF-8 or UTF-16, if it is not then at some point when processing the
2243 input, the converter/checker of UTF-8 form will raise an encoding error.
2244 You may end-up with a garbled document, or no document at all ! Example:
2245 <pre>~/XML -&gt; ./xmllint err.xml
2246err.xml:1: error: Input is not proper UTF-8, indicate encoding !
2247&lt;très&gt;là&lt;/très&gt;
2248 ^
2249err.xml:1: error: Bytes: 0xE8 0x73 0x3E 0x6C
2250&lt;très&gt;là&lt;/très&gt;
2251 ^</pre>
2252 </li>
2253 <li>xmlSwitchEncoding() does an encoding name lookup, canonalize it, and
2254 then search the default registered encoding converters for that encoding.
2255 If it's not within the default set and iconv() support has been compiled
2256 it, it will ask iconv for such an encoder. If this fails then the parser
2257 will report an error and stops processing:
2258 <pre>~/XML -&gt; ./xmllint err2.xml
2259err2.xml:1: error: Unsupported encoding UnsupportedEnc
2260&lt;?xml version="1.0" encoding="UnsupportedEnc"?&gt;
2261 ^</pre>
2262 </li>
2263 <li>From that point the encoder process progressingly the input (it is
2264 plugged as a front-end to the I/O module) for that entity. It captures
2265 and convert on-the-fly the document to be parsed to UTF-8. The parser
2266 itself just does UTF-8 checking of this input and process it
2267 transparently. The only difference is that the encoding information has
2268 been added to the parsing context (more precisely to the input
2269 corresponding to this entity).</li>
2270 <li>The result (when using DOM) is an internal form completely in UTF-8
2271 with just an encoding information on the document node.</li>
2272</ol>
2273
2274<p>Ok then what's happen when saving the document (assuming you
2275colllected/built an xmlDoc DOM like structure) ? It depends on the function
2276called, xmlSaveFile() will just try to save in the original encoding, while
2277xmlSaveFileTo() and xmlSaveFileEnc() can optionally save to a given
2278encoding:</p>
2279<ol>
2280 <li>if no encoding is given, libxml will look for an encoding value
2281 associated to the document and if it exists will try to save to that
2282 encoding,
2283 <p>otherwise everything is written in the internal form, i.e. UTF-8</p>
2284 </li>
2285 <li>so if an encoding was specified, either at the API level or on the
2286 document, libxml will again canonalize the encoding name, lookup for a
2287 converter in the registered set or through iconv. If not found the
2288 function will return an error code</li>
2289 <li>the converter is placed before the I/O buffer layer, as another kind of
2290 buffer, then libxml will simply push the UTF-8 serialization to through
2291 that buffer, which will then progressively be converted and pushed onto
2292 the I/O layer.</li>
2293 <li>It is possible that the converter code fails on some input, for example
2294 trying to push an UTF-8 encoded chinese character through the UTF-8 to
2295 ISO-8859-1 converter won't work. Since the encoders are progressive they
2296 will just report the error and the number of bytes converted, at that
2297 point libxml will decode the offending character, remove it from the
2298 buffer and replace it with the associated charRef encoding &amp;#123; and
2299 resume the convertion. This guarante that any document will be saved
2300 without losses (except for markup names where this is not legal, this is
2301 a problem in the current version, in pactice avoid using non-ascci
2302 characters for tags or attributes names @@). A special "ascii" encoding
2303 name is used to save documents to a pure ascii form can be used when
2304 portability is really crucial</li>
2305</ol>
2306
2307<p>Here is a few examples based on the same test document:</p>
2308<pre>~/XML -&gt; ./xmllint isolat1
2309&lt;?xml version="1.0" encoding="ISO-8859-1"?&gt;
2310&lt;très&gt;là&lt;/très&gt;
2311~/XML -&gt; ./xmllint --encode UTF-8 isolat1
2312&lt;?xml version="1.0" encoding="UTF-8"?&gt;
2313&lt;très&gt;là  &lt;/très&gt;
2314~/XML -&gt; </pre>
2315
2316<p>The same processing is applied (and reuse most of the code) for HTML I18N
2317processing. Looking up and modifying the content encoding is a bit more
2318difficult since it is located in a &lt;meta&gt; tag under the &lt;head&gt;,
2319so a couple of functions htmlGetMetaEncoding() and htmlSetMetaEncoding() have
2320been provided. The parser also attempts to switch encoding on the fly when
2321detecting such a tag on input. Except for that the processing is the same
2322(and again reuses the same code).</p>
2323
2324<h3><a name="Default">Default supported encodings</a></h3>
2325
2326<p>libxml has a set of default converters for the following encodings
2327(located in encoding.c):</p>
2328<ol>
2329 <li>UTF-8 is supported by default (null handlers)</li>
2330 <li>UTF-16, both little and big endian</li>
2331 <li>ISO-Latin-1 (ISO-8859-1) covering most western languages</li>
2332 <li>ASCII, useful mostly for saving</li>
2333 <li>HTML, a specific handler for the conversion of UTF-8 to ASCII with HTML
2334 predefined entities like &amp;copy; for the Copyright sign.</li>
2335</ol>
2336
2337<p>More over when compiled on an Unix platfor with iconv support the full set
2338of encodings supported by iconv can be instantly be used by libxml. On a
2339linux machine with glibc-2.1 the list of supported encodings and aliases fill
23403 full pages, and include UCS-4, the full set of ISO-Latin encodings, and the
2341various Japanese ones.</p>
2342
2343<h4>Encoding aliases</h4>
2344
2345<p>From 2.2.3, libxml has support to register encoding names aliases. The
2346goal is to be able to parse document whose encoding is supported but where
2347the name differs (for example from the default set of names accepted by
2348iconv). The following functions allow to register and handle new aliases for
2349existing encodings. Once registered libxml will automatically lookup the
2350aliases when handling a document:</p>
2351<ul>
2352 <li>int xmlAddEncodingAlias(const char *name, const char *alias);</li>
2353 <li>int xmlDelEncodingAlias(const char *alias);</li>
2354 <li>const char * xmlGetEncodingAlias(const char *alias);</li>
2355 <li>void xmlCleanupEncodingAliases(void);</li>
2356</ul>
2357
2358<h3><a name="extend">How to extend the existing support</a></h3>
2359
2360<p>Well adding support for new encoding, or overriding one of the encoders
2361(assuming it is buggy) should not be hard, just write an input and output
2362conversion routines to/from UTF-8, and register them using
2363xmlNewCharEncodingHandler(name, xxxToUTF8, UTF8Toxxx), and they will be
2364called automatically if the parser(s) encounter such an encoding name
2365(register it uppercase, this will help). The description of the encoders,
2366their arguments and expected return values are described in the encoding.h
2367header.</p>
2368
2369<p>A quick note on the topic of subverting the parser to use a different
2370internal encoding than UTF-8, in some case people will absolutely want to
2371keep the internal encoding different, I think it's still possible (but the
2372encoding must be compliant with ASCII on the same subrange) though I didn't
2373tried it. The key is to override the default conversion routines (by
2374registering null encoders/decoders for your charsets), and bypass the UTF-8
2375checking of the parser by setting the parser context charset
2376(ctxt-&gt;charset) to something different than XML_CHAR_ENCODING_UTF8, but
2377there is no guarantee taht this will work. You may also have some troubles
2378saving back.</p>
2379
2380<p>Basically proper I18N support is important, this requires at least
2381libxml-2.0.0, but a lot of features and corrections are really available only
2382starting 2.2.</p>
2383
2384<h2><a name="IO">I/O Interfaces</a></h2>
2385
2386<p>Table of Content:</p>
2387<ol>
2388 <li><a href="#General1">General overview</a></li>
2389 <li><a href="#basic">The basic buffer type</a></li>
2390 <li><a href="#Input">Input I/O handlers</a></li>
2391 <li><a href="#Output">Output I/O handlers</a></li>
2392 <li><a href="#entities">The entities loader</a></li>
2393 <li><a href="#Example2">Example of customized I/O</a></li>
2394</ol>
2395
2396<h3><a name="General1">General overview</a></h3>
2397
2398<p>The module <code><a
2399href="http://xmlsoft.org/html/libxml-xmlio.html">xmlIO.h</a></code> provides
2400the interfaces to the libxml I/O system. This consists of 4 main parts:</p>
2401<ul>
2402 <li>Entities loader, this is a routine which tries to fetch the entities
2403 (files) based on their PUBLIC and SYSTEM identifiers. The default loader
2404 don't look at the public identifier since libxml do not maintain a
2405 catalog. You can redefine you own entity loader by using
2406 <code>xmlGetExternalEntityLoader()</code> and
Daniel Veillard9c466822001-10-25 12:03:39 +00002407 <code>xmlSetExternalEntityLoader()</code>. <a href="#entities">Check the
2408 example</a>.</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002409 <li>Input I/O buffers which are a commodity structure used by the parser(s)
2410 input layer to handle fetching the informations to feed the parser. This
2411 provides buffering and is also a placeholder where the encoding
2412 convertors to UTF8 are piggy-backed.</li>
2413 <li>Output I/O buffers are similar to the Input ones and fulfill similar
2414 task but when generating a serialization from a tree.</li>
2415 <li>A mechanism to register sets of I/O callbacks and associate them with
2416 specific naming schemes like the protocol part of the URIs.
2417 <p>This affect the default I/O operations and allows to use specific I/O
2418 handlers for certain names.</p>
2419 </li>
2420</ul>
2421
2422<p>The general mechanism used when loading http://rpmfind.net/xml.html for
2423example in the HTML parser is the following:</p>
2424<ol>
2425 <li>The default entity loader calls <code>xmlNewInputFromFile()</code> with
2426 the parsing context and the URI string.</li>
2427 <li>the URI string is checked against the existing registered handlers
2428 using their match() callback function, if the HTTP module was compiled
2429 in, it is registered and its match() function will succeeds</li>
2430 <li>the open() function of the handler is called and if successful will
2431 return an I/O Input buffer</li>
2432 <li>the parser will the start reading from this buffer and progressively
2433 fetch information from the resource, calling the read() function of the
2434 handler until the resource is exhausted</li>
2435 <li>if an encoding change is detected it will be installed on the input
2436 buffer, providing buffering and efficient use of the conversion
2437 routines</li>
2438 <li>once the parser has finished, the close() function of the handler is
2439 called once and the Input buffer and associed resources are
2440 deallocated.</li>
2441</ol>
2442
2443<p>The user defined callbacks are checked first to allow overriding of the
2444default libxml I/O routines.</p>
2445
2446<h3><a name="basic">The basic buffer type</a></h3>
2447
2448<p>All the buffer manipulation handling is done using the
2449<code>xmlBuffer</code> type define in <code><a
2450href="http://xmlsoft.org/html/libxml-tree.html">tree.h</a> </code>which is a
2451resizable memory buffer. The buffer allocation strategy can be selected to be
2452either best-fit or use an exponential doubling one (CPU vs. memory use
2453tradeoff). The values are <code>XML_BUFFER_ALLOC_EXACT</code> and
2454<code>XML_BUFFER_ALLOC_DOUBLEIT</code>, and can be set individually or on a
2455system wide basis using <code>xmlBufferSetAllocationScheme()</code>. A number
2456of functions allows to manipulate buffers with names starting with the
2457<code>xmlBuffer...</code> prefix.</p>
2458
2459<h3><a name="Input">Input I/O handlers</a></h3>
2460
2461<p>An Input I/O handler is a simple structure
2462<code>xmlParserInputBuffer</code> containing a context associated to the
2463resource (file descriptor, or pointer to a protocol handler), the read() and
2464close() callbacks to use and an xmlBuffer. And extra xmlBuffer and a charset
2465encoding handler are also present to support charset conversion when
2466needed.</p>
2467
2468<h3><a name="Output">Output I/O handlers</a></h3>
2469
2470<p>An Output handler <code>xmlOutputBuffer</code> is completely similar to an
2471Input one except the callbacks are write() and close().</p>
2472
2473<h3><a name="entities">The entities loader</a></h3>
2474
2475<p>The entity loader resolves requests for new entities and create inputs for
2476the parser. Creating an input from a filename or an URI string is done
2477through the xmlNewInputFromFile() routine. The default entity loader do not
2478handle the PUBLIC identifier associated with an entity (if any). So it just
2479calls xmlNewInputFromFile() with the SYSTEM identifier (which is mandatory in
2480XML).</p>
2481
2482<p>If you want to hook up a catalog mechanism then you simply need to
2483override the default entity loader, here is an example:</p>
2484<pre>#include &lt;libxml/xmlIO.h&gt;
2485
2486xmlExternalEntityLoader defaultLoader = NULL;
2487
2488xmlParserInputPtr
2489xmlMyExternalEntityLoader(const char *URL, const char *ID,
2490 xmlParserCtxtPtr ctxt) {
2491 xmlParserInputPtr ret;
2492 const char *fileID = NULL;
2493 /* lookup for the fileID depending on ID */
2494
2495 ret = xmlNewInputFromFile(ctxt, fileID);
2496 if (ret != NULL)
2497 return(ret);
2498 if (defaultLoader != NULL)
2499 ret = defaultLoader(URL, ID, ctxt);
2500 return(ret);
2501}
2502
2503int main(..) {
2504 ...
2505
2506 /*
2507 * Install our own entity loader
2508 */
2509 defaultLoader = xmlGetExternalEntityLoader();
2510 xmlSetExternalEntityLoader(xmlMyExternalEntityLoader);
2511
2512 ...
2513}</pre>
2514
2515<h3><a name="Example2">Example of customized I/O</a></h3>
2516
2517<p>This example come from <a href="http://xmlsoft.org/messages/0708.html">a
2518real use case</a>, xmlDocDump() closes the FILE * passed by the application
2519and this was a problem. The <a
2520href="http://xmlsoft.org/messages/0711.html">solution</a> was to redefine a
2521new output handler with the closing call deactivated:</p>
2522<ol>
2523 <li>First define a new I/O ouput allocator where the output don't close the
2524 file:
2525 <pre>xmlOutputBufferPtr
2526xmlOutputBufferCreateOwn(FILE *file, xmlCharEncodingHandlerPtr encoder) {
2527    xmlOutputBufferPtr ret;
2528    
2529    if (xmlOutputCallbackInitialized == 0)
2530        xmlRegisterDefaultOutputCallbacks();
2531
2532    if (file == NULL) return(NULL);
2533    ret = xmlAllocOutputBuffer(encoder);
2534    if (ret != NULL) {
2535        ret-&gt;context = file;
2536        ret-&gt;writecallback = xmlFileWrite;
2537        ret-&gt;closecallback = NULL; /* No close callback */
2538    }
2539    return(ret); <br>
Daniel Veillard1eb24242002-03-18 11:33:03 +00002540
Daniel Veillard34ce8be2002-03-18 19:37:11 +00002541
2542
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002543} </pre>
2544 </li>
2545 <li>And then use it to save the document:
2546 <pre>FILE *f;
2547xmlOutputBufferPtr output;
2548xmlDocPtr doc;
2549int res;
2550
2551f = ...
2552doc = ....
2553
2554output = xmlOutputBufferCreateOwn(f, NULL);
2555res = xmlSaveFileTo(output, doc, NULL);
2556 </pre>
2557 </li>
2558</ol>
2559
2560<h2><a name="Catalog">Catalog support</a></h2>
2561
2562<p>Table of Content:</p>
2563<ol>
2564 <li><a href="General2">General overview</a></li>
2565 <li><a href="#definition">The definition</a></li>
2566 <li><a href="#Simple">Using catalogs</a></li>
2567 <li><a href="#Some">Some examples</a></li>
2568 <li><a href="#reference">How to tune catalog usage</a></li>
2569 <li><a href="#validate">How to debug catalog processing</a></li>
2570 <li><a href="#Declaring">How to create and maintain catalogs</a></li>
2571 <li><a href="#implemento">The implementor corner quick review of the
2572 API</a></li>
2573 <li><a href="#Other">Other resources</a></li>
2574</ol>
2575
2576<h3><a name="General2">General overview</a></h3>
2577
2578<p>What is a catalog? Basically it's a lookup mechanism used when an entity
2579(a file or a remote resource) references another entity. The catalog lookup
2580is inserted between the moment the reference is recognized by the software
2581(XML parser, stylesheet processing, or even images referenced for inclusion
2582in a rendering) and the time where loading that resource is actually
2583started.</p>
2584
2585<p>It is basically used for 3 things:</p>
2586<ul>
2587 <li>mapping from "logical" names, the public identifiers and a more
2588 concrete name usable for download (and URI). For example it can associate
2589 the logical name
2590 <p>"-//OASIS//DTD DocBook XML V4.1.2//EN"</p>
2591 <p>of the DocBook 4.1.2 XML DTD with the actual URL where it can be
2592 downloaded</p>
2593 <p>http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd</p>
2594 </li>
2595 <li>remapping from a given URL to another one, like an HTTP indirection
2596 saying that
2597 <p>"http://www.oasis-open.org/committes/tr.xsl"</p>
2598 <p>should really be looked at</p>
2599 <p>"http://www.oasis-open.org/committes/entity/stylesheets/base/tr.xsl"</p>
2600 </li>
2601 <li>providing a local cache mechanism allowing to load the entities
2602 associated to public identifiers or remote resources, this is a really
2603 important feature for any significant deployment of XML or SGML since it
2604 allows to avoid the aleas and delays associated to fetching remote
2605 resources.</li>
2606</ul>
2607
2608<h3><a name="definition">The definitions</a></h3>
2609
2610<p>Libxml, as of 2.4.3 implements 2 kind of catalogs:</p>
2611<ul>
2612 <li>the older SGML catalogs, the official spec is SGML Open Technical
2613 Resolution TR9401:1997, but is better understood by reading <a
2614 href="http://www.jclark.com/sp/catalog.htm">the SP Catalog page</a> from
2615 James Clark. This is relatively old and not the preferred mode of
2616 operation of libxml.</li>
2617 <li><a href="http://www.oasis-open.org/committees/entity/spec.html">XML
Daniel Veillardaf43f632002-03-08 15:05:20 +00002618 Catalogs</a> is far more flexible, more recent, uses an XML syntax and
2619 should scale quite better. This is the default option of libxml.</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002620</ul>
2621
2622<p></p>
2623
2624<h3><a name="Simple">Using catalog</a></h3>
2625
2626<p>In a normal environment libxml will by default check the presence of a
2627catalog in /etc/xml/catalog, and assuming it has been correctly populated,
2628the processing is completely transparent to the document user. To take a
2629concrete example, suppose you are authoring a DocBook document, this one
2630starts with the following DOCTYPE definition:</p>
2631<pre>&lt;?xml version='1.0'?&gt;
2632&lt;!DOCTYPE book PUBLIC "-//Norman Walsh//DTD DocBk XML V3.1.4//EN"
2633 "http://nwalsh.com/docbook/xml/3.1.4/db3xml.dtd"&gt;</pre>
2634
2635<p>When validating the document with libxml, the catalog will be
2636automatically consulted to lookup the public identifier "-//Norman Walsh//DTD
2637DocBk XML V3.1.4//EN" and the system identifier
2638"http://nwalsh.com/docbook/xml/3.1.4/db3xml.dtd", and if these entities have
2639been installed on your system and the catalogs actually point to them, libxml
2640will fetch them from the local disk.</p>
2641
2642<p style="font-size: 10pt"><strong>Note</strong>: Really don't use this
2643DOCTYPE example it's a really old version, but is fine as an example.</p>
2644
2645<p>Libxml will check the catalog each time that it is requested to load an
2646entity, this includes DTD, external parsed entities, stylesheets, etc ... If
2647your system is correctly configured all the authoring phase and processing
2648should use only local files, even if your document stays portable because it
2649uses the canonical public and system ID, referencing the remote document.</p>
2650
2651<h3><a name="Some">Some examples:</a></h3>
2652
2653<p>Here is a couple of fragments from XML Catalogs used in libxml early
2654regression tests in <code>test/catalogs</code> :</p>
2655<pre>&lt;?xml version="1.0"?&gt;
2656&lt;!DOCTYPE catalog PUBLIC
2657 "-//OASIS//DTD Entity Resolution XML Catalog V1.0//EN"
2658 "http://www.oasis-open.org/committees/entity/release/1.0/catalog.dtd"&gt;
2659&lt;catalog xmlns="urn:oasis:names:tc:entity:xmlns:xml:catalog"&gt;
2660 &lt;public publicId="-//OASIS//DTD DocBook XML V4.1.2//EN"
2661 uri="http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd"/&gt;
2662...</pre>
2663
2664<p>This is the beginning of a catalog for DocBook 4.1.2, XML Catalogs are
2665written in XML, there is a specific namespace for catalog elements
2666"urn:oasis:names:tc:entity:xmlns:xml:catalog". The first entry in this
2667catalog is a <code>public</code> mapping it allows to associate a Public
2668Identifier with an URI.</p>
2669<pre>...
2670 &lt;rewriteSystem systemIdStartString="http://www.oasis-open.org/docbook/"
2671 rewritePrefix="file:///usr/share/xml/docbook/"/&gt;
2672...</pre>
2673
2674<p>A <code>rewriteSystem</code> is a very powerful instruction, it says that
2675any URI starting with a given prefix should be looked at another URI
2676constructed by replacing the prefix with an new one. In effect this acts like
2677a cache system for a full area of the Web. In practice it is extremely useful
2678with a file prefix if you have installed a copy of those resources on your
2679local system.</p>
2680<pre>...
2681&lt;delegatePublic publicIdStartString="-//OASIS//DTD XML Catalog //"
2682 catalog="file:///usr/share/xml/docbook.xml"/&gt;
2683&lt;delegatePublic publicIdStartString="-//OASIS//ENTITIES DocBook XML"
2684 catalog="file:///usr/share/xml/docbook.xml"/&gt;
2685&lt;delegatePublic publicIdStartString="-//OASIS//DTD DocBook XML"
2686 catalog="file:///usr/share/xml/docbook.xml"/&gt;
2687&lt;delegateSystem systemIdStartString="http://www.oasis-open.org/docbook/"
2688 catalog="file:///usr/share/xml/docbook.xml"/&gt;
2689&lt;delegateURI uriStartString="http://www.oasis-open.org/docbook/"
2690 catalog="file:///usr/share/xml/docbook.xml"/&gt;
2691...</pre>
2692
2693<p>Delegation is the core features which allows to build a tree of catalogs,
2694easier to maintain than a single catalog, based on Public Identifier, System
2695Identifier or URI prefixes it instructs the catalog software to look up
2696entries in another resource. This feature allow to build hierarchies of
2697catalogs, the set of entries presented should be sufficient to redirect the
2698resolution of all DocBook references to the specific catalog in
2699<code>/usr/share/xml/docbook.xml</code> this one in turn could delegate all
2700references for DocBook 4.2.1 to a specific catalog installed at the same time
2701as the DocBook resources on the local machine.</p>
2702
2703<h3><a name="reference">How to tune catalog usage:</a></h3>
2704
2705<p>The user can change the default catalog behaviour by redirecting queries
2706to its own set of catalogs, this can be done by setting the
2707<code>XML_CATALOG_FILES</code> environment variable to a list of catalogs, an
2708empty one should deactivate loading the default <code>/etc/xml/catalog</code>
2709default catalog</p>
2710
2711<h3><a name="validate">How to debug catalog processing:</a></h3>
2712
2713<p>Setting up the <code>XML_DEBUG_CATALOG</code> environment variable will
2714make libxml output debugging informations for each catalog operations, for
2715example:</p>
2716<pre>orchis:~/XML -&gt; xmllint --memory --noout test/ent2
2717warning: failed to load external entity "title.xml"
2718orchis:~/XML -&gt; export XML_DEBUG_CATALOG=
2719orchis:~/XML -&gt; xmllint --memory --noout test/ent2
2720Failed to parse catalog /etc/xml/catalog
2721Failed to parse catalog /etc/xml/catalog
2722warning: failed to load external entity "title.xml"
2723Catalogs cleanup
2724orchis:~/XML -&gt; </pre>
2725
2726<p>The test/ent2 references an entity, running the parser from memory makes
2727the base URI unavailable and the the "title.xml" entity cannot be loaded.
2728Setting up the debug environment variable allows to detect that an attempt is
2729made to load the <code>/etc/xml/catalog</code> but since it's not present the
2730resolution fails.</p>
2731
2732<p>But the most advanced way to debug XML catalog processing is to use the
2733<strong>xmlcatalog</strong> command shipped with libxml2, it allows to load
2734catalogs and make resolution queries to see what is going on. This is also
2735used for the regression tests:</p>
2736<pre>orchis:~/XML -&gt; ./xmlcatalog test/catalogs/docbook.xml \
2737 "-//OASIS//DTD DocBook XML V4.1.2//EN"
2738http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd
2739orchis:~/XML -&gt; </pre>
2740
2741<p>For debugging what is going on, adding one -v flags increase the verbosity
2742level to indicate the processing done (adding a second flag also indicate
2743what elements are recognized at parsing):</p>
2744<pre>orchis:~/XML -&gt; ./xmlcatalog -v test/catalogs/docbook.xml \
2745 "-//OASIS//DTD DocBook XML V4.1.2//EN"
2746Parsing catalog test/catalogs/docbook.xml's content
2747Found public match -//OASIS//DTD DocBook XML V4.1.2//EN
2748http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd
2749Catalogs cleanup
2750orchis:~/XML -&gt; </pre>
2751
2752<p>A shell interface is also available to debug and process multiple queries
2753(and for regression tests):</p>
2754<pre>orchis:~/XML -&gt; ./xmlcatalog -shell test/catalogs/docbook.xml \
2755 "-//OASIS//DTD DocBook XML V4.1.2//EN"
2756&gt; help
2757Commands available:
2758public PublicID: make a PUBLIC identifier lookup
2759system SystemID: make a SYSTEM identifier lookup
2760resolve PublicID SystemID: do a full resolver lookup
2761add 'type' 'orig' 'replace' : add an entry
2762del 'values' : remove values
2763dump: print the current catalog state
2764debug: increase the verbosity level
2765quiet: decrease the verbosity level
2766exit: quit the shell
2767&gt; public "-//OASIS//DTD DocBook XML V4.1.2//EN"
2768http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd
2769&gt; quit
2770orchis:~/XML -&gt; </pre>
2771
2772<p>This should be sufficient for most debugging purpose, this was actually
2773used heavily to debug the XML Catalog implementation itself.</p>
2774
2775<h3><a name="Declaring">How to create and maintain</a> catalogs:</h3>
2776
2777<p>Basically XML Catalogs are XML files, you can either use XML tools to
2778manage them or use <strong>xmlcatalog</strong> for this. The basic step is
2779to create a catalog the -create option provide this facility:</p>
2780<pre>orchis:~/XML -&gt; ./xmlcatalog --create tst.xml
2781&lt;?xml version="1.0"?&gt;
2782&lt;!DOCTYPE catalog PUBLIC "-//OASIS//DTD Entity Resolution XML Catalog V1.0//EN"
2783 "http://www.oasis-open.org/committees/entity/release/1.0/catalog.dtd"&gt;
2784&lt;catalog xmlns="urn:oasis:names:tc:entity:xmlns:xml:catalog"/&gt;
2785orchis:~/XML -&gt; </pre>
2786
2787<p>By default xmlcatalog does not overwrite the original catalog and save the
2788result on the standard output, this can be overridden using the -noout
2789option. The <code>-add</code> command allows to add entries in the
2790catalog:</p>
2791<pre>orchis:~/XML -&gt; ./xmlcatalog --noout --create --add "public" \
2792 "-//OASIS//DTD DocBook XML V4.1.2//EN" \
2793 http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd tst.xml
2794orchis:~/XML -&gt; cat tst.xml
2795&lt;?xml version="1.0"?&gt;
2796&lt;!DOCTYPE catalog PUBLIC "-//OASIS//DTD Entity Resolution XML Catalog V1.0//EN" \
2797 "http://www.oasis-open.org/committees/entity/release/1.0/catalog.dtd"&gt;
2798&lt;catalog xmlns="urn:oasis:names:tc:entity:xmlns:xml:catalog"&gt;
2799&lt;public publicId="-//OASIS//DTD DocBook XML V4.1.2//EN"
2800 uri="http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd"/&gt;
2801&lt;/catalog&gt;
2802orchis:~/XML -&gt; </pre>
2803
2804<p>The <code>-add</code> option will always take 3 parameters even if some of
2805the XML Catalog constructs (like nextCatalog) will have only a single
2806argument, just pass a third empty string, it will be ignored.</p>
2807
2808<p>Similarly the <code>-del</code> option remove matching entries from the
2809catalog:</p>
2810<pre>orchis:~/XML -&gt; ./xmlcatalog --del \
2811 "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd" tst.xml
2812&lt;?xml version="1.0"?&gt;
2813&lt;!DOCTYPE catalog PUBLIC "-//OASIS//DTD Entity Resolution XML Catalog V1.0//EN"
2814 "http://www.oasis-open.org/committees/entity/release/1.0/catalog.dtd"&gt;
2815&lt;catalog xmlns="urn:oasis:names:tc:entity:xmlns:xml:catalog"/&gt;
2816orchis:~/XML -&gt; </pre>
2817
2818<p>The catalog is now empty. Note that the matching of <code>-del</code> is
2819exact and would have worked in a similar fashion with the Public ID
2820string.</p>
2821
2822<p>This is rudimentary but should be sufficient to manage a not too complex
2823catalog tree of resources.</p>
2824
2825<h3><a name="implemento">The implementor corner quick review of the
2826API:</a></h3>
2827
2828<p>First, and like for every other module of libxml, there is an
2829automatically generated <a href="html/libxml-catalog.html">API page for
2830catalog support</a>.</p>
2831
2832<p>The header for the catalog interfaces should be included as:</p>
2833<pre>#include &lt;libxml/catalog.h&gt;</pre>
2834
2835<p>The API is voluntarily kept very simple. First it is not obvious that
2836applications really need access to it since it is the default behaviour of
2837libxml (Note: it is possible to completely override libxml default catalog by
2838using <a href="html/libxml-parser.html">xmlSetExternalEntityLoader</a> to
2839plug an application specific resolver).</p>
2840
2841<p>Basically libxml support 2 catalog lists:</p>
2842<ul>
2843 <li>the default one, global shared by all the application</li>
2844 <li>a per-document catalog, this one is built if the document uses the
2845 <code>oasis-xml-catalog</code> PIs to specify its own catalog list, it is
2846 associated to the parser context and destroyed when the parsing context
2847 is destroyed.</li>
2848</ul>
2849
2850<p>the document one will be used first if it exists.</p>
2851
2852<h4>Initialization routines:</h4>
2853
2854<p>xmlInitializeCatalog(), xmlLoadCatalog() and xmlLoadCatalogs() should be
2855used at startup to initialize the catalog, if the catalog should be
2856initialized with specific values xmlLoadCatalog() or xmlLoadCatalogs()
2857should be called before xmlInitializeCatalog() which would otherwise do a
2858default initialization first.</p>
2859
2860<p>The xmlCatalogAddLocal() call is used by the parser to grow the document
2861own catalog list if needed.</p>
2862
2863<h4>Preferences setup:</h4>
2864
2865<p>The XML Catalog spec requires the possibility to select default
2866preferences between public and system delegation,
2867xmlCatalogSetDefaultPrefer() allows this, xmlCatalogSetDefaults() and
2868xmlCatalogGetDefaults() allow to control if XML Catalogs resolution should
2869be forbidden, allowed for global catalog, for document catalog or both, the
2870default is to allow both.</p>
2871
2872<p>And of course xmlCatalogSetDebug() allows to generate debug messages
2873(through the xmlGenericError() mechanism).</p>
2874
2875<h4>Querying routines:</h4>
2876
2877<p>xmlCatalogResolve(), xmlCatalogResolveSystem(), xmlCatalogResolvePublic()
2878and xmlCatalogResolveURI() are relatively explicit if you read the XML
2879Catalog specification they correspond to section 7 algorithms, they should
2880also work if you have loaded an SGML catalog with a simplified semantic.</p>
2881
2882<p>xmlCatalogLocalResolve() and xmlCatalogLocalResolveURI() are the same but
2883operate on the document catalog list</p>
2884
2885<h4>Cleanup and Miscellaneous:</h4>
2886
2887<p>xmlCatalogCleanup() free-up the global catalog, xmlCatalogFreeLocal() is
2888the per-document equivalent.</p>
2889
2890<p>xmlCatalogAdd() and xmlCatalogRemove() are used to dynamically modify the
2891first catalog in the global list, and xmlCatalogDump() allows to dump a
2892catalog state, those routines are primarily designed for xmlcatalog, I'm not
2893sure that exposing more complex interfaces (like navigation ones) would be
2894really useful.</p>
2895
2896<p>The xmlParseCatalogFile() is a function used to load XML Catalog files,
2897it's similar as xmlParseFile() except it bypass all catalog lookups, it's
2898provided because this functionality may be useful for client tools.</p>
2899
2900<h4>threaded environments:</h4>
2901
2902<p>Since the catalog tree is built progressively, some care has been taken to
2903try to avoid troubles in multithreaded environments. The code is now thread
2904safe assuming that the libxml library has been compiled with threads
2905support.</p>
2906
2907<p></p>
2908
2909<h3><a name="Other">Other resources</a></h3>
2910
2911<p>The XML Catalog specification is relatively recent so there isn't much
2912literature to point at:</p>
2913<ul>
2914 <li>You can find an good rant from Norm Walsh about <a
2915 href="http://www.arbortext.com/Think_Tank/XML_Resources/Issue_Three/issue_three.html">the
2916 need for catalogs</a>, it provides a lot of context informations even if
2917 I don't agree with everything presented.</li>
2918 <li>An <a href="http://home.ccil.org/~cowan/XML/XCatalog.html">old XML
2919 catalog proposal</a> from John Cowan</li>
2920 <li>The <a href="http://www.rddl.org/">Resource Directory Description
2921 Language</a> (RDDL) another catalog system but more oriented toward
2922 providing metadata for XML namespaces.</li>
2923 <li>the page from the OASIS Technical <a
2924 href="http://www.oasis-open.org/committees/entity/">Committee on Entity
2925 Resolution</a> who maintains XML Catalog, you will find pointers to the
2926 specification update, some background and pointers to others tools
2927 providing XML Catalog support</li>
Daniel Veillard35e937a2002-01-19 22:21:54 +00002928 <li>Here is a <a href="buildDocBookCatalog">shell script</a> to generate
2929 XML Catalogs for DocBook 4.1.2 . If it can write to the /etc/xml/
2930 directory, it will set-up /etc/xml/catalog and /etc/xml/docbook based on
2931 the resources found on the system. Otherwise it will just create
2932 ~/xmlcatalog and ~/dbkxmlcatalog and doing:
Daniel Veillardc575b992002-02-08 13:28:40 +00002933 <p><code>export XMLCATALOG=$HOME/xmlcatalog</code></p>
Daniel Veillard35e937a2002-01-19 22:21:54 +00002934 <p>should allow to process DocBook documentations without requiring
2935 network accesses for the DTd or stylesheets</p>
2936 </li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002937 <li>I have uploaded <a href="ftp://xmlsoft.org/test/dbk412catalog.tar.gz">a
Daniel Veillard35e937a2002-01-19 22:21:54 +00002938 small tarball</a> containing XML Catalogs for DocBook 4.1.2 which seems
2939 to work fine for me too</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00002940 <li>The <a href="http://www.xmlsoft.org/xmlcatalog_man.html">xmlcatalog
2941 manual page</a></li>
2942</ul>
2943
2944<p>If you have suggestions for corrections or additions, simply contact
2945me:</p>
2946
2947<h2><a name="library">The parser interfaces</a></h2>
Daniel Veillardb05deb71999-08-10 19:04:08 +00002948
2949<p>This section is directly intended to help programmers getting bootstrapped
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +00002950using the XML library from the C language. It is not intended to be
2951extensive. I hope the automatically generated documents will provide the
2952completeness required, but as a separate set of documents. The interfaces of
2953the XML library are by principle low level, there is nearly zero abstraction.
2954Those interested in a higher level API should <a href="#DOM">look at
2955DOM</a>.</p>
Daniel Veillardccb09631998-10-27 06:21:04 +00002956
Daniel Veillard9cb5ff42001-01-29 08:22:21 +00002957<p>The <a href="html/libxml-parser.html">parser interfaces for XML</a> are
2958separated from the <a href="html/libxml-htmlparser.html">HTML parser
Daniel Veillard88f00ae2000-03-02 00:15:55 +00002959interfaces</a>. Let's have a look at how the XML parser can be called:</p>
Daniel Veillard0142b842000-01-14 14:45:24 +00002960
Daniel Veillard88f00ae2000-03-02 00:15:55 +00002961<h3><a name="Invoking">Invoking the parser : the pull method</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +00002962
Daniel Veillard88f00ae2000-03-02 00:15:55 +00002963<p>Usually, the first thing to do is to read an XML input. The parser accepts
2964documents either from in-memory strings or from files. The functions are
Daniel Veillardb05deb71999-08-10 19:04:08 +00002965defined in "parser.h":</p>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +00002966<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +00002967 <dt><code>xmlDocPtr xmlParseMemory(char *buffer, int size);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +00002968 <dd><p>Parse a null-terminated string containing the document.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +00002969 </dd>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +00002970</dl>
2971<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +00002972 <dt><code>xmlDocPtr xmlParseFile(const char *filename);</code></dt>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +00002973 <dd><p>Parse an XML document contained in a (possibly compressed)
2974 file.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +00002975 </dd>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +00002976</dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +00002977
Daniel Veillard88f00ae2000-03-02 00:15:55 +00002978<p>The parser returns a pointer to the document structure (or NULL in case of
Daniel Veillard10c6a8f1998-10-28 01:00:12 +00002979failure).</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +00002980
Daniel Veillard88f00ae2000-03-02 00:15:55 +00002981<h3 id="Invoking1">Invoking the parser: the push method</h3>
Daniel Veillard0142b842000-01-14 14:45:24 +00002982
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +00002983<p>In order for the application to keep the control when the document is
2984being fetched (which is common for GUI based programs) libxml provides a push
Daniel Veillard88f00ae2000-03-02 00:15:55 +00002985interface, too, as of version 1.8.3. Here are the interface functions:</p>
Daniel Veillard0142b842000-01-14 14:45:24 +00002986<pre>xmlParserCtxtPtr xmlCreatePushParserCtxt(xmlSAXHandlerPtr sax,
2987 void *user_data,
2988 const char *chunk,
2989 int size,
2990 const char *filename);
2991int xmlParseChunk (xmlParserCtxtPtr ctxt,
2992 const char *chunk,
2993 int size,
2994 int terminate);</pre>
2995
Daniel Veillard88f00ae2000-03-02 00:15:55 +00002996<p>and here is a simple example showing how to use the interface:</p>
Daniel Veillard0142b842000-01-14 14:45:24 +00002997<pre> FILE *f;
2998
2999 f = fopen(filename, "r");
3000 if (f != NULL) {
3001 int res, size = 1024;
3002 char chars[1024];
3003 xmlParserCtxtPtr ctxt;
3004
3005 res = fread(chars, 1, 4, f);
Daniel Veillard60979bd2000-07-10 12:17:33 +00003006 if (res &gt; 0) {
Daniel Veillard0142b842000-01-14 14:45:24 +00003007 ctxt = xmlCreatePushParserCtxt(NULL, NULL,
3008 chars, res, filename);
Daniel Veillard60979bd2000-07-10 12:17:33 +00003009 while ((res = fread(chars, 1, size, f)) &gt; 0) {
Daniel Veillard0142b842000-01-14 14:45:24 +00003010 xmlParseChunk(ctxt, chars, res, 0);
3011 }
3012 xmlParseChunk(ctxt, chars, 0, 1);
Daniel Veillard60979bd2000-07-10 12:17:33 +00003013 doc = ctxt-&gt;myDoc;
Daniel Veillard0142b842000-01-14 14:45:24 +00003014 xmlFreeParserCtxt(ctxt);
3015 }
3016 }</pre>
3017
Daniel Veillardec70e912001-02-26 20:10:45 +00003018<p>The HTML parser embedded into libxml also has a push interface; the
3019functions are just prefixed by "html" rather than "xml".</p>
Daniel Veillard0142b842000-01-14 14:45:24 +00003020
3021<h3 id="Invoking2">Invoking the parser: the SAX interface</h3>
3022
Daniel Veillardec70e912001-02-26 20:10:45 +00003023<p>The tree-building interface makes the parser memory-hungry, first loading
3024the document in memory and then building the tree itself. Reading a document
3025without building the tree is possible using the SAX interfaces (see SAX.h and
3026<a href="http://www.daa.com.au/~james/gnome/xml-sax/xml-sax.html">James
Daniel Veillard88f00ae2000-03-02 00:15:55 +00003027Henstridge's documentation</a>). Note also that the push interface can be
Daniel Veillard91e9d582001-02-26 07:31:12 +00003028limited to SAX: just use the two first arguments of
Daniel Veillard0142b842000-01-14 14:45:24 +00003029<code>xmlCreatePushParserCtxt()</code>.</p>
Daniel Veillardccb09631998-10-27 06:21:04 +00003030
Daniel Veillard2f4dfc41999-09-24 14:03:48 +00003031<h3><a name="Building">Building a tree from scratch</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003032
3033<p>The other way to get an XML tree in memory is by building it. Basically
Daniel Veillardf13e1ed2000-03-06 07:41:49 +00003034there is a set of functions dedicated to building new elements. (These are
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +00003035also described in &lt;libxml/tree.h&gt;.) For example, here is a piece of
3036code that produces the XML document used in the previous examples:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +00003037<pre> #include &lt;libxml/tree.h&gt;
Daniel Veillard361d8452000-04-03 19:48:13 +00003038 xmlDocPtr doc;
Daniel Veillard25940b71998-10-29 05:51:30 +00003039 xmlNodePtr tree, subtree;
3040
3041 doc = xmlNewDoc("1.0");
Daniel Veillard60979bd2000-07-10 12:17:33 +00003042 doc-&gt;children = xmlNewDocNode(doc, NULL, "EXAMPLE", NULL);
3043 xmlSetProp(doc-&gt;children, "prop1", "gnome is great");
3044 xmlSetProp(doc-&gt;children, "prop2", "&amp; linux too");
3045 tree = xmlNewChild(doc-&gt;children, NULL, "head", NULL);
Daniel Veillard25940b71998-10-29 05:51:30 +00003046 subtree = xmlNewChild(tree, NULL, "title", "Welcome to Gnome");
Daniel Veillard60979bd2000-07-10 12:17:33 +00003047 tree = xmlNewChild(doc-&gt;children, NULL, "chapter", NULL);
Daniel Veillard25940b71998-10-29 05:51:30 +00003048 subtree = xmlNewChild(tree, NULL, "title", "The Linux adventure");
3049 subtree = xmlNewChild(tree, NULL, "p", "bla bla bla ...");
3050 subtree = xmlNewChild(tree, NULL, "image", NULL);
3051 xmlSetProp(subtree, "href", "linus.gif");</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003052
3053<p>Not really rocket science ...</p>
Daniel Veillard25940b71998-10-29 05:51:30 +00003054
Daniel Veillard2f4dfc41999-09-24 14:03:48 +00003055<h3><a name="Traversing">Traversing the tree</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003056
Daniel Veillard9cb5ff42001-01-29 08:22:21 +00003057<p>Basically by <a href="html/libxml-tree.html">including "tree.h"</a> your
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +00003058code has access to the internal structure of all the elements of the tree.
3059The names should be somewhat simple like <strong>parent</strong>,
Daniel Veillard306be992000-07-03 12:38:45 +00003060<strong>children</strong>, <strong>next</strong>, <strong>prev</strong>,
Daniel Veillard88f00ae2000-03-02 00:15:55 +00003061<strong>properties</strong>, etc... For example, still with the previous
Daniel Veillard0142b842000-01-14 14:45:24 +00003062example:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +00003063<pre><code>doc-&gt;children-&gt;children-&gt;children</code></pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003064
3065<p>points to the title element,</p>
Daniel Veillard91e9d582001-02-26 07:31:12 +00003066<pre>doc-&gt;children-&gt;children-&gt;next-&gt;children-&gt;children</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003067
Daniel Veillardf13e1ed2000-03-06 07:41:49 +00003068<p>points to the text node containing the chapter title "The Linux
3069adventure".</p>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +00003070
Daniel Veillardb24054a1999-12-18 15:32:46 +00003071<p><strong>NOTE</strong>: XML allows <em>PI</em>s and <em>comments</em> to be
Daniel Veillard60979bd2000-07-10 12:17:33 +00003072present before the document root, so <code>doc-&gt;children</code> may point
Daniel Veillard91e9d582001-02-26 07:31:12 +00003073to an element which is not the document Root Element; a function
Daniel Veillard5cb5ab81999-12-21 15:35:29 +00003074<code>xmlDocGetRootElement()</code> was added for this purpose.</p>
Daniel Veillardb24054a1999-12-18 15:32:46 +00003075
Daniel Veillard2f4dfc41999-09-24 14:03:48 +00003076<h3><a name="Modifying">Modifying the tree</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003077
Daniel Veillard88f00ae2000-03-02 00:15:55 +00003078<p>Functions are provided for reading and writing the document content. Here
Daniel Veillard9cb5ff42001-01-29 08:22:21 +00003079is an excerpt from the <a href="html/libxml-tree.html">tree API</a>:</p>
Daniel Veillard25940b71998-10-29 05:51:30 +00003080<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +00003081 <dt><code>xmlAttrPtr xmlSetProp(xmlNodePtr node, const xmlChar *name, const
3082 xmlChar *value);</code></dt>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +00003083 <dd><p>This sets (or changes) an attribute carried by an ELEMENT node.
3084 The value can be NULL.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003085 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +00003086</dl>
3087<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +00003088 <dt><code>const xmlChar *xmlGetProp(xmlNodePtr node, const xmlChar
Daniel Veillardb05deb71999-08-10 19:04:08 +00003089 *name);</code></dt>
Daniel Veillardc92c3042000-09-29 02:42:04 +00003090 <dd><p>This function returns a pointer to new copy of the property
3091 content. Note that the user must deallocate the result.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003092 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +00003093</dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003094
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +00003095<p>Two functions are provided for reading and writing the text associated
3096with elements:</p>
Daniel Veillard25940b71998-10-29 05:51:30 +00003097<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +00003098 <dt><code>xmlNodePtr xmlStringGetNodeList(xmlDocPtr doc, const xmlChar
Daniel Veillardb05deb71999-08-10 19:04:08 +00003099 *value);</code></dt>
Daniel Veillardec70e912001-02-26 20:10:45 +00003100 <dd><p>This function takes an "external" string and converts it to one
3101 text node or possibly to a list of entity and text nodes. All
3102 non-predefined entity references like &amp;Gnome; will be stored
3103 internally as entity nodes, hence the result of the function may not be
3104 a single node.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003105 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +00003106</dl>
3107<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +00003108 <dt><code>xmlChar *xmlNodeListGetString(xmlDocPtr doc, xmlNodePtr list, int
Daniel Veillardb05deb71999-08-10 19:04:08 +00003109 inLine);</code></dt>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +00003110 <dd><p>This function is the inverse of
3111 <code>xmlStringGetNodeList()</code>. It generates a new string
3112 containing the content of the text and entity nodes. Note the extra
3113 argument inLine. If this argument is set to 1, the function will expand
3114 entity references. For example, instead of returning the &amp;Gnome;
3115 XML encoding in the string, it will substitute it with its value (say,
Daniel Veillard91e9d582001-02-26 07:31:12 +00003116 "GNU Network Object Model Environment").</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003117 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +00003118</dl>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +00003119
Daniel Veillard2f4dfc41999-09-24 14:03:48 +00003120<h3><a name="Saving">Saving a tree</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003121
3122<p>Basically 3 options are possible:</p>
Daniel Veillard25940b71998-10-29 05:51:30 +00003123<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +00003124 <dt><code>void xmlDocDumpMemory(xmlDocPtr cur, xmlChar**mem, int
Daniel Veillardb05deb71999-08-10 19:04:08 +00003125 *size);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +00003126 <dd><p>Returns a buffer into which the document has been saved.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003127 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +00003128</dl>
3129<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003130 <dt><code>extern void xmlDocDump(FILE *f, xmlDocPtr doc);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +00003131 <dd><p>Dumps a document to an open file descriptor.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003132 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +00003133</dl>
3134<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003135 <dt><code>int xmlSaveFile(const char *filename, xmlDocPtr cur);</code></dt>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +00003136 <dd><p>Saves the document to a file. In this case, the compression
3137 interface is triggered if it has been turned on.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003138 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +00003139</dl>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +00003140
Daniel Veillard2f4dfc41999-09-24 14:03:48 +00003141<h3><a name="Compressio">Compression</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003142
Daniel Veillard88f00ae2000-03-02 00:15:55 +00003143<p>The library transparently handles compression when doing file-based
Daniel Veillardf13e1ed2000-03-06 07:41:49 +00003144accesses. The level of compression on saves can be turned on either globally
3145or individually for one file:</p>
Daniel Veillard25940b71998-10-29 05:51:30 +00003146<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003147 <dt><code>int xmlGetDocCompressMode (xmlDocPtr doc);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +00003148 <dd><p>Gets the document compression ratio (0-9).</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003149 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +00003150</dl>
3151<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003152 <dt><code>void xmlSetDocCompressMode (xmlDocPtr doc, int mode);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +00003153 <dd><p>Sets the document compression ratio.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003154 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +00003155</dl>
3156<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003157 <dt><code>int xmlGetCompressMode(void);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +00003158 <dd><p>Gets the default compression ratio.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003159 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +00003160</dl>
3161<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003162 <dt><code>void xmlSetCompressMode(int mode);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +00003163 <dd><p>Sets the default compression ratio.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003164 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +00003165</dl>
3166
Daniel Veillard2f4dfc41999-09-24 14:03:48 +00003167<h2><a name="Entities">Entities or no entities</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00003168
Daniel Veillard88f00ae2000-03-02 00:15:55 +00003169<p>Entities in principle are similar to simple C macros. An entity defines an
3170abbreviation for a given string that you can reuse many times throughout the
3171content of your document. Entities are especially useful when a given string
Daniel Veillardf13e1ed2000-03-06 07:41:49 +00003172may occur frequently within a document, or to confine the change needed to a
3173document to a restricted area in the internal subset of the document (at the
3174beginning). Example:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +00003175<pre>1 &lt;?xml version="1.0"?&gt;
Daniel Veillardc8eab3a1999-09-04 18:27:23 +000031762 &lt;!DOCTYPE EXAMPLE SYSTEM "example.dtd" [
Daniel Veillard60979bd2000-07-10 12:17:33 +000031773 &lt;!ENTITY xml "Extensible Markup Language"&gt;
31784 ]&gt;
31795 &lt;EXAMPLE&gt;
Daniel Veillardc8eab3a1999-09-04 18:27:23 +000031806 &amp;xml;
Daniel Veillard60979bd2000-07-10 12:17:33 +000031817 &lt;/EXAMPLE&gt;</pre>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00003182
3183<p>Line 3 declares the xml entity. Line 6 uses the xml entity, by prefixing
Daniel Veillard91e9d582001-02-26 07:31:12 +00003184its name with '&amp;' and following it by ';' without any spaces added. There
Daniel Veillard88f00ae2000-03-02 00:15:55 +00003185are 5 predefined entities in libxml allowing you to escape charaters with
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00003186predefined meaning in some parts of the xml document content:
Daniel Veillard88f00ae2000-03-02 00:15:55 +00003187<strong>&amp;lt;</strong> for the character '&lt;', <strong>&amp;gt;</strong>
Daniel Veillard60979bd2000-07-10 12:17:33 +00003188for the character '&gt;', <strong>&amp;apos;</strong> for the character ''',
Daniel Veillard88f00ae2000-03-02 00:15:55 +00003189<strong>&amp;quot;</strong> for the character '"', and
3190<strong>&amp;amp;</strong> for the character '&amp;'.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00003191
3192<p>One of the problems related to entities is that you may want the parser to
Daniel Veillardf13e1ed2000-03-06 07:41:49 +00003193substitute an entity's content so that you can see the replacement text in
3194your application. Or you may prefer to keep entity references as such in the
3195content to be able to save the document back without losing this usually
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +00003196precious information (if the user went through the pain of explicitly
3197defining entities, he may have a a rather negative attitude if you blindly
3198susbtitute them as saving time). The <a
Daniel Veillard9cb5ff42001-01-29 08:22:21 +00003199href="html/libxml-parser.html#XMLSUBSTITUTEENTITIESDEFAULT">xmlSubstituteEntitiesDefault()</a>
Daniel Veillard88f00ae2000-03-02 00:15:55 +00003200function allows you to check and change the behaviour, which is to not
3201substitute entities by default.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00003202
3203<p>Here is the DOM tree built by libxml for the previous document in the
3204default case:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +00003205<pre>/gnome/src/gnome-xml -&gt; ./xmllint --debug test/ent1
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00003206DOCUMENT
3207version=1.0
3208 ELEMENT EXAMPLE
3209 TEXT
3210 content=
3211 ENTITY_REF
3212 INTERNAL_GENERAL_ENTITY xml
3213 content=Extensible Markup Language
3214 TEXT
3215 content=</pre>
3216
3217<p>And here is the result when substituting entities:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +00003218<pre>/gnome/src/gnome-xml -&gt; ./tester --debug --noent test/ent1
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00003219DOCUMENT
3220version=1.0
3221 ELEMENT EXAMPLE
3222 TEXT
3223 content= Extensible Markup Language</pre>
3224
Daniel Veillard88f00ae2000-03-02 00:15:55 +00003225<p>So, entities or no entities? Basically, it depends on your use case. I
3226suggest that you keep the non-substituting default behaviour and avoid using
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00003227entities in your XML document or data if you are not willing to handle the
3228entity references elements in the DOM tree.</p>
3229
Daniel Veillard91e9d582001-02-26 07:31:12 +00003230<p>Note that at save time libxml enforces the conversion of the predefined
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00003231entities where necessary to prevent well-formedness problems, and will also
Daniel Veillard91e9d582001-02-26 07:31:12 +00003232transparently replace those with chars (i.e. it will not generate entity
Daniel Veillard88f00ae2000-03-02 00:15:55 +00003233reference elements in the DOM tree or call the reference() SAX callback when
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00003234finding them in the input).</p>
3235
Daniel Veillard7b9c4b72000-08-25 16:26:50 +00003236<p><span style="background-color: #FF0000">WARNING</span>: handling entities
Daniel Veillard91e9d582001-02-26 07:31:12 +00003237on top of the libxml SAX interface is difficult!!! If you plan to use
Daniel Veillard7b9c4b72000-08-25 16:26:50 +00003238non-predefined entities in your documents, then the learning cuvre to handle
Daniel Veillard91e9d582001-02-26 07:31:12 +00003239then using the SAX API may be long. If you plan to use complex documents, I
Daniel Veillard7b9c4b72000-08-25 16:26:50 +00003240strongly suggest you consider using the DOM interface instead and let libxml
Daniel Veillard8c6d6af2000-08-25 17:14:13 +00003241deal with the complexity rather than trying to do it yourself.</p>
Daniel Veillard7b9c4b72000-08-25 16:26:50 +00003242
Daniel Veillard2f4dfc41999-09-24 14:03:48 +00003243<h2><a name="Namespaces">Namespaces</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00003244
Daniel Veillardec303412000-03-24 13:41:54 +00003245<p>The libxml library implements <a
3246href="http://www.w3.org/TR/REC-xml-names/">XML namespaces</a> support by
3247recognizing namespace contructs in the input, and does namespace lookup
3248automatically when building the DOM tree. A namespace declaration is
3249associated with an in-memory structure and all elements or attributes within
3250that namespace point to it. Hence testing the namespace is a simple and fast
3251equality operation at the user level.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00003252
Daniel Veillardf13e1ed2000-03-06 07:41:49 +00003253<p>I suggest that people using libxml use a namespace, and declare it in the
3254root element of their document as the default namespace. Then they don't need
3255to use the prefix in the content but we will have a basis for future semantic
Daniel Veillard91e9d582001-02-26 07:31:12 +00003256refinement and merging of data from different sources. This doesn't increase
Daniel Veillardec70e912001-02-26 20:10:45 +00003257the size of the XML output significantly, but significantly increases its
3258value in the long-term. Example:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +00003259<pre>&lt;mydoc xmlns="http://mydoc.example.org/schemas/"&gt;
3260 &lt;elem1&gt;...&lt;/elem1&gt;
3261 &lt;elem2&gt;...&lt;/elem2&gt;
3262&lt;/mydoc&gt;</pre>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00003263
Daniel Veillardec70e912001-02-26 20:10:45 +00003264<p>The namespace value has to be an absolute URL, but the URL doesn't have to
3265point to any existing resource on the Web. It will bind all the element and
3266atributes with that URL. I suggest to use an URL within a domain you control,
3267and that the URL should contain some kind of version information if possible.
3268For example, <code>"http://www.gnome.org/gnumeric/1.0/"</code> is a good
3269namespace scheme.</p>
Daniel Veillardec303412000-03-24 13:41:54 +00003270
3271<p>Then when you load a file, make sure that a namespace carrying the
Daniel Veillard88f00ae2000-03-02 00:15:55 +00003272version-independent prefix is installed on the root element of your document,
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00003273and if the version information don't match something you know, warn the user
3274and be liberal in what you accept as the input. Also do *not* try to base
Daniel Veillard60979bd2000-07-10 12:17:33 +00003275namespace checking on the prefix value. &lt;foo:text&gt; may be exactly the
Daniel Veillard91e9d582001-02-26 07:31:12 +00003276same as &lt;bar:text&gt; in another document. What really matters is the URI
Daniel Veillard60979bd2000-07-10 12:17:33 +00003277associated with the element or the attribute, not the prefix string (which is
Daniel Veillard91e9d582001-02-26 07:31:12 +00003278just a shortcut for the full URI). In libxml, element and attributes have an
Daniel Veillardec303412000-03-24 13:41:54 +00003279<code>ns</code> field pointing to an xmlNs structure detailing the namespace
Daniel Veillard91e9d582001-02-26 07:31:12 +00003280prefix and its URI.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00003281
3282<p>@@Interfaces@@</p>
3283
3284<p>@@Examples@@</p>
3285
Daniel Veillard91e9d582001-02-26 07:31:12 +00003286<p>Usually people object to using namespaces together with validity checking.
3287I will try to make sure that using namespaces won't break validity checking,
3288so even if you plan to use or currently are using validation I strongly
Daniel Veillardf13e1ed2000-03-06 07:41:49 +00003289suggest adding namespaces to your document. A default namespace scheme
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00003290<code>xmlns="http://...."</code> should not break validity even on less
Daniel Veillard91e9d582001-02-26 07:31:12 +00003291flexible parsers. Using namespaces to mix and differentiate content coming
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +00003292from multiple DTDs will certainly break current validation schemes. I will
3293try to provide ways to do this, but this may not be portable or
3294standardized.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00003295
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00003296<h2><a name="Upgrading">Upgrading 1.x code</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00003297
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00003298<p>Incompatible changes:</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00003299
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00003300<p>Version 2 of libxml is the first version introducing serious backward
3301incompatible changes. The main goals were:</p>
3302<ul>
3303 <li>a general cleanup. A number of mistakes inherited from the very early
3304 versions couldn't be changed due to compatibility constraints. Example
3305 the "childs" element in the nodes.</li>
3306 <li>Uniformization of the various nodes, at least for their header and link
3307 parts (doc, parent, children, prev, next), the goal is a simpler
3308 programming model and simplifying the task of the DOM implementors.</li>
3309 <li>better conformances to the XML specification, for example version 1.x
3310 had an heuristic to try to detect ignorable white spaces. As a result the
3311 SAX event generated were ignorableWhitespace() while the spec requires
3312 character() in that case. This also mean that a number of DOM node
3313 containing blank text may populate the DOM tree which were not present
3314 before.</li>
3315</ul>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00003316
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00003317<h3>How to fix libxml-1.x code:</h3>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00003318
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00003319<p>So client code of libxml designed to run with version 1.x may have to be
3320changed to compile against version 2.x of libxml. Here is a list of changes
3321that I have collected, they may not be sufficient, so in case you find other
3322change which are required, <a href="mailto:Daniel.Ïeillardw3.org">drop me a
3323mail</a>:</p>
3324<ol>
3325 <li>The package name have changed from libxml to libxml2, the library name
3326 is now -lxml2 . There is a new xml2-config script which should be used to
3327 select the right parameters libxml2</li>
3328 <li>Node <strong>childs</strong> field has been renamed
3329 <strong>children</strong> so s/childs/children/g should be applied
3330 (probablility of having "childs" anywere else is close to 0+</li>
3331 <li>The document don't have anymore a <strong>root</strong> element it has
3332 been replaced by <strong>children</strong> and usually you will get a
3333 list of element here. For example a Dtd element for the internal subset
3334 and it's declaration may be found in that list, as well as processing
3335 instructions or comments found before or after the document root element.
3336 Use <strong>xmlDocGetRootElement(doc)</strong> to get the root element of
3337 a document. Alternatively if you are sure to not reference Dtds nor have
3338 PIs or comments before or after the root element
3339 s/-&gt;root/-&gt;children/g will probably do it.</li>
3340 <li>The white space issue, this one is more complex, unless special case of
3341 validating parsing, the line breaks and spaces usually used for indenting
3342 and formatting the document content becomes significant. So they are
3343 reported by SAX and if your using the DOM tree, corresponding nodes are
3344 generated. Too approach can be taken:
3345 <ol>
3346 <li>lazy one, use the compatibility call
3347 <strong>xmlKeepBlanksDefault(0)</strong> but be aware that you are
3348 relying on a special (and possibly broken) set of heuristics of
3349 libxml to detect ignorable blanks. Don't complain if it breaks or
3350 make your application not 100% clean w.r.t. to it's input.</li>
3351 <li>the Right Way: change you code to accept possibly unsignificant
3352 blanks characters, or have your tree populated with weird blank text
3353 nodes. You can spot them using the comodity function
3354 <strong>xmlIsBlankNode(node)</strong> returning 1 for such blank
3355 nodes.</li>
3356 </ol>
3357 <p>Note also that with the new default the output functions don't add any
3358 extra indentation when saving a tree in order to be able to round trip
3359 (read and save) without inflating the document with extra formatting
3360 chars.</p>
3361 </li>
3362 <li>The include path has changed to $prefix/libxml/ and the includes
3363 themselves uses this new prefix in includes instructions... If you are
3364 using (as expected) the
3365 <pre>xml2-config --cflags</pre>
3366 <p>output to generate you compile commands this will probably work out of
3367 the box</p>
3368 </li>
3369 <li>xmlDetectCharEncoding takes an extra argument indicating the lenght in
3370 byte of the head of the document available for character detection.</li>
3371</ol>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00003372
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00003373<h3>Ensuring both libxml-1.x and libxml-2.x compatibility</h3>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00003374
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00003375<p>Two new version of libxml (1.8.11) and libxml2 (2.3.4) have been released
3376to allow smoth upgrade of existing libxml v1code while retaining
3377compatibility. They offers the following:</p>
3378<ol>
3379 <li>similar include naming, one should use
3380 <strong>#include&lt;libxml/...&gt;</strong> in both cases.</li>
3381 <li>similar identifiers defined via macros for the child and root fields:
3382 respectively <strong>xmlChildrenNode</strong> and
3383 <strong>xmlRootNode</strong></li>
3384 <li>a new macro <strong>LIBXML_TEST_VERSION</strong> which should be
3385 inserted once in the client code</li>
3386</ol>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00003387
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00003388<p>So the roadmap to upgrade your existing libxml applications is the
3389following:</p>
3390<ol>
3391 <li>install the libxml-1.8.8 (and libxml-devel-1.8.8) packages</li>
3392 <li>find all occurences where the xmlDoc <strong>root</strong> field is
3393 used and change it to <strong>xmlRootNode</strong></li>
3394 <li>similary find all occurences where the xmlNode <strong>childs</strong>
3395 field is used and change it to <strong>xmlChildrenNode</strong></li>
3396 <li>add a <strong>LIBXML_TEST_VERSION</strong> macro somewhere in your
3397 <strong>main()</strong> or in the library init entry point</li>
3398 <li>Recompile, check compatibility, it should still work</li>
3399 <li>Change your configure script to look first for xml2-config and fallback
3400 using xml-config . Use the --cflags and --libs ouptut of the command as
3401 the Include and Linking parameters needed to use libxml.</li>
3402 <li>install libxml2-2.3.x and libxml2-devel-2.3.x (libxml-1.8.y and
3403 libxml-devel-1.8.y can be kept simultaneously)</li>
3404 <li>remove your config.cache, relaunch your configuration mechanism, and
3405 recompile, if steps 2 and 3 were done right it should compile as-is</li>
3406 <li>Test that your application is still running correctly, if not this may
3407 be due to extra empty nodes due to formating spaces being kept in libxml2
3408 contrary to libxml1, in that case insert xmlKeepBlanksDefault(1) in your
3409 code before calling the parser (next to
3410 <strong>LIBXML_TEST_VERSION</strong> is a fine place).</li>
3411</ol>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00003412
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00003413<p>Following those steps should work. It worked for some of my own code.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00003414
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00003415<p>Let me put some emphasis on the fact that there is far more changes from
3416libxml 1.x to 2.x than the ones you may have to patch for. The overall code
3417has been considerably cleaned up and the conformance to the XML specification
3418has been drastically improved too. Don't take those changes as an excuse to
3419not upgrade, it may cost a lot on the long term ...</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00003420
Daniel Veillard52dcab32001-10-30 12:51:17 +00003421<h2><a name="Thread">Thread safety</a></h2>
3422
3423<p>Starting with 2.4.7, libxml makes provisions to ensure that concurent
3424threads can safely work in parallel parsing different documents. There is
3425however a couple of things to do to ensure it:</p>
3426<ul>
3427 <li>configure the library accordingly using the --with-threads options</li>
3428 <li>call xmlInitParser() in the "main" thread before using any of the
3429 libxml API (except possibly selecting a different memory allocator)</li>
3430</ul>
3431
3432<p>Note that the thread safety cannot be ensured for multiple threads sharing
3433the same document, the locking must be done at the application level, libxml
3434exports a basic mutex and reentrant mutexes API in &lt;libxml/threads.h&gt;.
3435The parts of the library checked for thread safety are:</p>
3436<ul>
3437 <li>concurrent loading</li>
3438 <li>file access resolution</li>
3439 <li>catalog access</li>
3440 <li>catalog building</li>
3441 <li>entities lookup/accesses</li>
3442 <li>validation</li>
3443 <li>global variables per-thread override</li>
3444 <li>memory handling</li>
3445</ul>
3446
3447<p>XPath is supposed to be thread safe now, but this wasn't tested
3448seriously.</p>
3449
Daniel Veillard35008381999-10-25 13:15:52 +00003450<h2><a name="DOM"></a><a name="Principles">DOM Principles</a></h2>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003451
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +00003452<p><a href="http://www.w3.org/DOM/">DOM</a> stands for the <em>Document
3453Object Model</em>; this is an API for accessing XML or HTML structured
3454documents. Native support for DOM in Gnome is on the way (module gnome-dom),
3455and will be based on gnome-xml. This will be a far cleaner interface to
3456manipulate XML files within Gnome since it won't expose the internal
3457structure.</p>
Daniel Veillard14fff061999-06-22 21:49:07 +00003458
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00003459<p>The current DOM implementation on top of libxml is the <a
Daniel Veillarda47fb3d2001-03-25 17:23:49 +00003460href="http://cvs.gnome.org/lxr/source/gdome2/">gdome2 Gnome module</a>, this
3461is a full DOM interface, thanks to Paolo Casarini, check the <a
3462href="http://www.cs.unibo.it/~casarini/gdome2/">Gdome2 homepage</a> for more
3463informations.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00003464
Daniel Veillard35008381999-10-25 13:15:52 +00003465<h2><a name="Example"></a><a name="real">A real example</a></h2>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003466
3467<p>Here is a real size example, where the actual content of the application
3468data is not kept in the DOM tree but uses internal structures. It is based on
Daniel Veillard14fff061999-06-22 21:49:07 +00003469a proposal to keep a database of jobs related to Gnome, with an XML based
Daniel Veillardb05deb71999-08-10 19:04:08 +00003470storage structure. Here is an <a href="gjobs.xml">XML encoded jobs
3471base</a>:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +00003472<pre>&lt;?xml version="1.0"?&gt;
3473&lt;gjob:Helping xmlns:gjob="http://www.gnome.org/some-location"&gt;
3474 &lt;gjob:Jobs&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +00003475
Daniel Veillard60979bd2000-07-10 12:17:33 +00003476 &lt;gjob:Job&gt;
3477 &lt;gjob:Project ID="3"/&gt;
3478 &lt;gjob:Application&gt;GBackup&lt;/gjob:Application&gt;
3479 &lt;gjob:Category&gt;Development&lt;/gjob:Category&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +00003480
Daniel Veillard60979bd2000-07-10 12:17:33 +00003481 &lt;gjob:Update&gt;
3482 &lt;gjob:Status&gt;Open&lt;/gjob:Status&gt;
3483 &lt;gjob:Modified&gt;Mon, 07 Jun 1999 20:27:45 -0400 MET DST&lt;/gjob:Modified&gt;
3484 &lt;gjob:Salary&gt;USD 0.00&lt;/gjob:Salary&gt;
3485 &lt;/gjob:Update&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +00003486
Daniel Veillard60979bd2000-07-10 12:17:33 +00003487 &lt;gjob:Developers&gt;
3488 &lt;gjob:Developer&gt;
3489 &lt;/gjob:Developer&gt;
3490 &lt;/gjob:Developers&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +00003491
Daniel Veillard60979bd2000-07-10 12:17:33 +00003492 &lt;gjob:Contact&gt;
3493 &lt;gjob:Person&gt;Nathan Clemons&lt;/gjob:Person&gt;
3494 &lt;gjob:Email&gt;nathan@windsofstorm.net&lt;/gjob:Email&gt;
3495 &lt;gjob:Company&gt;
3496 &lt;/gjob:Company&gt;
3497 &lt;gjob:Organisation&gt;
3498 &lt;/gjob:Organisation&gt;
3499 &lt;gjob:Webpage&gt;
3500 &lt;/gjob:Webpage&gt;
3501 &lt;gjob:Snailmail&gt;
3502 &lt;/gjob:Snailmail&gt;
3503 &lt;gjob:Phone&gt;
3504 &lt;/gjob:Phone&gt;
3505 &lt;/gjob:Contact&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +00003506
Daniel Veillard60979bd2000-07-10 12:17:33 +00003507 &lt;gjob:Requirements&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +00003508 The program should be released as free software, under the GPL.
Daniel Veillard60979bd2000-07-10 12:17:33 +00003509 &lt;/gjob:Requirements&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +00003510
Daniel Veillard60979bd2000-07-10 12:17:33 +00003511 &lt;gjob:Skills&gt;
3512 &lt;/gjob:Skills&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +00003513
Daniel Veillard60979bd2000-07-10 12:17:33 +00003514 &lt;gjob:Details&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +00003515 A GNOME based system that will allow a superuser to configure
3516 compressed and uncompressed files and/or file systems to be backed
3517 up with a supported media in the system. This should be able to
3518 perform via find commands generating a list of files that are passed
3519 to tar, dd, cpio, cp, gzip, etc., to be directed to the tape machine
3520 or via operations performed on the filesystem itself. Email
3521 notification and GUI status display very important.
Daniel Veillard60979bd2000-07-10 12:17:33 +00003522 &lt;/gjob:Details&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +00003523
Daniel Veillard60979bd2000-07-10 12:17:33 +00003524 &lt;/gjob:Job&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +00003525
Daniel Veillard60979bd2000-07-10 12:17:33 +00003526 &lt;/gjob:Jobs&gt;
3527&lt;/gjob:Helping&gt;</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003528
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +00003529<p>While loading the XML file into an internal DOM tree is a matter of
3530calling only a couple of functions, browsing the tree to gather the ata and
3531generate the internal structures is harder, and more error prone.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003532
3533<p>The suggested principle is to be tolerant with respect to the input
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +00003534structure. For example, the ordering of the attributes is not significant,
3535the XML specification is clear about it. It's also usually a good idea not to
Daniel Veillardec70e912001-02-26 20:10:45 +00003536depend on the order of the children of a given node, unless it really makes
3537things harder. Here is some code to parse the information for a person:</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003538<pre>/*
Daniel Veillard14fff061999-06-22 21:49:07 +00003539 * A person record
3540 */
3541typedef struct person {
3542 char *name;
3543 char *email;
3544 char *company;
3545 char *organisation;
3546 char *smail;
3547 char *webPage;
3548 char *phone;
3549} person, *personPtr;
3550
3551/*
3552 * And the code needed to parse it
3553 */
3554personPtr parsePerson(xmlDocPtr doc, xmlNsPtr ns, xmlNodePtr cur) {
3555 personPtr ret = NULL;
3556
3557DEBUG("parsePerson\n");
3558 /*
3559 * allocate the struct
3560 */
3561 ret = (personPtr) malloc(sizeof(person));
3562 if (ret == NULL) {
3563 fprintf(stderr,"out of memory\n");
Daniel Veillardb05deb71999-08-10 19:04:08 +00003564 return(NULL);
Daniel Veillard14fff061999-06-22 21:49:07 +00003565 }
3566 memset(ret, 0, sizeof(person));
3567
3568 /* We don't care what the top level element name is */
Daniel Veillard60979bd2000-07-10 12:17:33 +00003569 cur = cur-&gt;xmlChildrenNode;
Daniel Veillard14fff061999-06-22 21:49:07 +00003570 while (cur != NULL) {
Daniel Veillard60979bd2000-07-10 12:17:33 +00003571 if ((!strcmp(cur-&gt;name, "Person")) &amp;&amp; (cur-&gt;ns == ns))
3572 ret-&gt;name = xmlNodeListGetString(doc, cur-&gt;xmlChildrenNode, 1);
3573 if ((!strcmp(cur-&gt;name, "Email")) &amp;&amp; (cur-&gt;ns == ns))
3574 ret-&gt;email = xmlNodeListGetString(doc, cur-&gt;xmlChildrenNode, 1);
3575 cur = cur-&gt;next;
Daniel Veillard14fff061999-06-22 21:49:07 +00003576 }
3577
3578 return(ret);
Daniel Veillardb05deb71999-08-10 19:04:08 +00003579}</pre>
3580
Daniel Veillard91e9d582001-02-26 07:31:12 +00003581<p>Here are a couple of things to notice:</p>
Daniel Veillard14fff061999-06-22 21:49:07 +00003582<ul>
Daniel Veillard91e9d582001-02-26 07:31:12 +00003583 <li>Usually a recursive parsing style is the more convenient one: XML data
3584 is by nature subject to repetitive constructs and usually exibits highly
Daniel Veillardb05deb71999-08-10 19:04:08 +00003585 stuctured patterns.</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +00003586 <li>The two arguments of type <em>xmlDocPtr</em> and <em>xmlNsPtr</em>,
3587 i.e. the pointer to the global XML document and the namespace reserved to
3588 the application. Document wide information are needed for example to
3589 decode entities and it's a good coding practice to define a namespace for
3590 your application set of data and test that the element and attributes
3591 you're analyzing actually pertains to your application space. This is
3592 done by a simple equality test (cur-&gt;ns == ns).</li>
Daniel Veillardec70e912001-02-26 20:10:45 +00003593 <li>To retrieve text and attributes value, you can use the function
3594 <em>xmlNodeListGetString</em> to gather all the text and entity reference
3595 nodes generated by the DOM output and produce an single text string.</li>
Daniel Veillard14fff061999-06-22 21:49:07 +00003596</ul>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003597
3598<p>Here is another piece of code used to parse another level of the
3599structure:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +00003600<pre>#include &lt;libxml/tree.h&gt;
Daniel Veillard361d8452000-04-03 19:48:13 +00003601/*
Daniel Veillard14fff061999-06-22 21:49:07 +00003602 * a Description for a Job
3603 */
3604typedef struct job {
3605 char *projectID;
3606 char *application;
3607 char *category;
3608 personPtr contact;
3609 int nbDevelopers;
3610 personPtr developers[100]; /* using dynamic alloc is left as an exercise */
3611} job, *jobPtr;
3612
3613/*
3614 * And the code needed to parse it
3615 */
3616jobPtr parseJob(xmlDocPtr doc, xmlNsPtr ns, xmlNodePtr cur) {
3617 jobPtr ret = NULL;
3618
3619DEBUG("parseJob\n");
3620 /*
3621 * allocate the struct
3622 */
3623 ret = (jobPtr) malloc(sizeof(job));
3624 if (ret == NULL) {
3625 fprintf(stderr,"out of memory\n");
Daniel Veillardb05deb71999-08-10 19:04:08 +00003626 return(NULL);
Daniel Veillard14fff061999-06-22 21:49:07 +00003627 }
3628 memset(ret, 0, sizeof(job));
3629
3630 /* We don't care what the top level element name is */
Daniel Veillard60979bd2000-07-10 12:17:33 +00003631 cur = cur-&gt;xmlChildrenNode;
Daniel Veillard14fff061999-06-22 21:49:07 +00003632 while (cur != NULL) {
3633
Daniel Veillard60979bd2000-07-10 12:17:33 +00003634 if ((!strcmp(cur-&gt;name, "Project")) &amp;&amp; (cur-&gt;ns == ns)) {
3635 ret-&gt;projectID = xmlGetProp(cur, "ID");
3636 if (ret-&gt;projectID == NULL) {
Daniel Veillardb05deb71999-08-10 19:04:08 +00003637 fprintf(stderr, "Project has no ID\n");
3638 }
3639 }
Daniel Veillard60979bd2000-07-10 12:17:33 +00003640 if ((!strcmp(cur-&gt;name, "Application")) &amp;&amp; (cur-&gt;ns == ns))
3641 ret-&gt;application = xmlNodeListGetString(doc, cur-&gt;xmlChildrenNode, 1);
3642 if ((!strcmp(cur-&gt;name, "Category")) &amp;&amp; (cur-&gt;ns == ns))
3643 ret-&gt;category = xmlNodeListGetString(doc, cur-&gt;xmlChildrenNode, 1);
3644 if ((!strcmp(cur-&gt;name, "Contact")) &amp;&amp; (cur-&gt;ns == ns))
3645 ret-&gt;contact = parsePerson(doc, ns, cur);
3646 cur = cur-&gt;next;
Daniel Veillard14fff061999-06-22 21:49:07 +00003647 }
3648
3649 return(ret);
Daniel Veillardb05deb71999-08-10 19:04:08 +00003650}</pre>
Daniel Veillard14fff061999-06-22 21:49:07 +00003651
Daniel Veillardec70e912001-02-26 20:10:45 +00003652<p>Once you are used to it, writing this kind of code is quite simple, but
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +00003653boring. Ultimately, it could be possble to write stubbers taking either C
3654data structure definitions, a set of XML examples or an XML DTD and produce
3655the code needed to import and export the content between C data and XML
3656storage. This is left as an exercise to the reader :-)</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003657
Daniel Veillard6f0adb52000-07-03 11:41:26 +00003658<p>Feel free to use <a href="example/gjobread.c">the code for the full C
3659parsing example</a> as a template, it is also available with Makefile in the
3660Gnome CVS base under gnome-xml/example</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +00003661
Daniel Veillardc310d562000-06-23 18:32:15 +00003662<h2><a name="Contributi">Contributions</a></h2>
3663<ul>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +00003664 <li>Bjorn Reese, William Brack and Thomas Broyer have provided a number of
3665 patches, Gary Pennington worked on the validation API, threading support
3666 and Solaris port.</li>
3667 <li>John Fleck helps maintaining the documentation and man pages.</li>
Daniel Veillardaf43f632002-03-08 15:05:20 +00003668 <li><a href="mailto:ari@lusis.org">Ari Johnson</a> provides a C++ wrapper
3669 for libxml:<br>
Daniel Veillardc6271d22001-10-27 07:50:58 +00003670 Website: <a
3671 href="http://lusis.org/~ari/xml++/">http://lusis.org/~ari/xml++/</a><br>
3672 Download: <a
Daniel Veillard51095312001-10-28 18:51:57 +00003673 href="http://lusis.org/~ari/xml++/libxml++.tar.gz">http://lusis.org/~ari/xml++/libxml++.tar.gz</a></li>
Daniel Veillardaf43f632002-03-08 15:05:20 +00003674 <li><a href="mailto:izlatkovic@daenet.de">Igor Zlatkovic</a> is now the
3675 maintainer of the Windows port, <a
Daniel Veillard95189532001-07-26 18:30:26 +00003676 href="http://www.fh-frankfurt.de/~igor/projects/libxml/index.html">he
3677 provides binaries</a></li>
Daniel Veillardaf43f632002-03-08 15:05:20 +00003678 <li><a href="mailto:Gary.Pennington@sun.com">Gary Pennington</a> provides
3679 <a href="http://garypennington.net/libxml2/">Solaris binaries</a></li>
Daniel Veillarde356c282001-03-10 12:32:04 +00003680 <li><a
3681 href="http://mail.gnome.org/archives/xml/2001-March/msg00014.html">Matt
Daniel Veillardaf43f632002-03-08 15:05:20 +00003682 Sergeant</a> developped <a
3683 href="http://axkit.org/download/">XML::LibXSLT</a>, a perl wrapper for
3684 libxml2/libxslt as part of the <a href="http://axkit.com/">AxKit XML
3685 application server</a></li>
3686 <li><a href="mailto:fnatter@gmx.net">Felix Natter</a> and <a
3687 href="mailto:geertk@ai.rug.nl">Geert Kloosterman</a> provide <a
Daniel Veillardca989762001-06-23 17:39:29 +00003688 href="libxml-doc.el">an emacs module</a> to lookup libxml(2) functions
Daniel Veillard3f6f7f62000-06-30 17:58:25 +00003689 documentation</li>
Daniel Veillardaf43f632002-03-08 15:05:20 +00003690 <li><a href="mailto:sherwin@nlm.nih.gov">Ziying Sherwin</a> provided <a
3691 href="http://xmlsoft.org/messages/0488.html">man pages</a></li>
Daniel Veillard5168dbf2001-07-07 00:18:23 +00003692 <li>there is a module for <a
3693 href="http://acs-misc.sourceforge.net/nsxml.html">libxml/libxslt support
3694 in OpenNSD/AOLServer</a></li>
Daniel Veillard2d347fa2002-03-17 10:34:11 +00003695 <li><a href="mailto:dkuhlman@cutter.rexx.com">Dave Kuhlman</a> provided the
3696 first version of libxml/libxslt <a
3697 href="http://www.rexx.com/~dkuhlman">wrappers for Python</a></li>
Daniel Veillard1aadc442001-11-28 13:10:32 +00003698 <li>Petr Kozelka provides <a
3699 href="http://sourceforge.net/projects/libxml2-pas">Pascal units to glue
3700 libxml2</a> with Kylix and Delphi and other Pascal compilers</li>
Daniel Veillard2d347fa2002-03-17 10:34:11 +00003701 <li><a href="mailto:aleksey@aleksey.com">Aleksey Sanin</a> implemented the
3702 <a href="http://www.w3.org/Signature/">XML Canonicalization and XML
3703 Digital Signature</a> <a
3704 href="http://www.aleksey.com/xmlsec/">implementations for libxml2</a></li>
Daniel Veillardc310d562000-06-23 18:32:15 +00003705</ul>
3706
Daniel Veillardc8eab3a1999-09-04 18:27:23 +00003707<p></p>
Daniel Veillardccb09631998-10-27 06:21:04 +00003708</body>
3709</html>