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Daniel Veillard09ab7e12001-07-10 15:49:44 +0000[diff] [blame]1<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
2 "http://www.w3.org/TR/html4/loose.dtd">
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]3<html>
4<head>
Daniel Veillardec78c0f2000-08-25 10:25:23 +0000[diff] [blame]5 <title>The XML C library for Gnome</title>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]6 <meta name="GENERATOR" content="amaya V5.0">
Daniel Veillardb24054a1999-12-18 15:32:46 +0000[diff] [blame]7 <meta http-equiv="Content-Type" content="text/html">
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]8</head>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]9
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]10<body bgcolor="#ffffff">
Daniel Veillardec78c0f2000-08-25 10:25:23 +0000[diff] [blame]11<h1 align="center">The XML C library for Gnome</h1>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]12
Daniel Veillard9c466822001-10-25 12:03:39 +0000[diff] [blame]13<h1>Note: this is the flat content of the <a href="index.html">web
14site</a></h1>
15
Daniel Veillardc9484202001-10-24 12:35:52 +0000[diff] [blame]16<h1 style="text-align: center">libxml, a.k.a. gnome-xml</h1>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]17
18<p></p>
Daniel Veillard9c466822001-10-25 12:03:39 +0000[diff] [blame]19
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
24markup language.</p>
25
26<p>Libxml2 implements a number of existing standards related to markup
27languages:</p>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]28<ul>
Daniel Veillard9c466822001-10-25 12:03:39 +0000[diff] [blame]29 <li>the XML standard: <a
30 href="http://www.w3.org/TR/REC-xml">http://www.w3.org/TR/REC-xml</a></li>
31 <li>Namespaces in XML: <a
32 href="http://www.w3.org/TR/REC-xml-names/">http://www.w3.org/TR/REC-xml-names/</a></li>
33 <li>XML Base: <a
34 href="http://www.w3.org/TR/xmlbase/">http://www.w3.org/TR/xmlbase/</a></li>
35 <li><a href="http://www.cis.ohio-state.edu/rfc/rfc2396.txt">RFC 2396</a>
Daniel Veillardc6271d22001-10-27 07:50:58 +0000[diff] [blame]36 : Uniform Resource Identifiers <a
Daniel Veillard9c466822001-10-25 12:03:39 +0000[diff] [blame]37 href="http://www.ietf.org/rfc/rfc2396.txt">http://www.ietf.org/rfc/rfc2396.txt</a></li>
38 <li>XML Path Language (XPath) 1.0: <a
39 href="http://www.w3.org/TR/xpath">http://www.w3.org/TR/xpath</a></li>
40 <li>HTML4 parser: <a
41 href="http://www.w3.org/TR/html401/">http://www.w3.org/TR/html401/</a></li>
42 <li>most of XML Pointer Language (XPointer) Version 1.0: <a
43 href="http://www.w3.org/TR/xptr">http://www.w3.org/TR/xptr</a></li>
44 <li>XML Inclusions (XInclude) Version 1.0: <a
45 href="http://www.w3.org/TR/xinclude/">http://www.w3.org/TR/xinclude/</a></li>
46 <li>[ISO-8859-1], <a
47 href="http://www.cis.ohio-state.edu/rfc/rfc2044.txt">rfc2044</a> [UTF-8]
48 and <a href="http://www.cis.ohio-state.edu/rfc/rfc2781.txt">rfc2781</a>
49 [UTF-16] core encodings</li>
50 <li>part of SGML Open Technical Resolution TR9401:1997</li>
51 <li>XML Catalogs Working Draft 06 August 2001: <a
52 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 Veillard96984452000-08-31 13:50:12 +0000[diff] [blame]53</ul>
54
Daniel Veillard9c466822001-10-25 12:03:39 +0000[diff] [blame]55<p>In most cases libxml tries to implement the specifications in a relatively
56strict way. To some extent libxml2 provide some support for the following
57other specification but don't claim to implement them:</p>
58<ul>
59 <li>Document Object Model (DOM) <a
60 href="http://www.w3.org/TR/DOM-Level-2-Core/">http://www.w3.org/TR/DOM-Level-2-Core/</a>
61 it doesn't implement the API itself, gdome2 does this in top of
62 libxml2</li>
63 <li><a href="http://www.cis.ohio-state.edu/rfc/rfc959.txt">RFC 959</a>
Daniel Veillardc6271d22001-10-27 07:50:58 +0000[diff] [blame]64 : libxml implements a basic FTP client code</li>
Daniel Veillard9c466822001-10-25 12:03:39 +0000[diff] [blame]65 <li><a href="http://www.cis.ohio-state.edu/rfc/rfc1945.txt">RFC 1945</a>
Daniel Veillardc6271d22001-10-27 07:50:58 +0000[diff] [blame]66 : HTTP/1.0, again a basic HTTP client code</li>
Daniel Veillard9c466822001-10-25 12:03:39 +0000[diff] [blame]67 <li>SAX: a minimal SAX implementation compatible with early expat
68 versions</li>
69 <li>DocBook SGML v4: libxml2 includes a hackish parser to transition to
70 XML</li>
71</ul>
72
73<p></p>
74
Daniel Veillard96984452000-08-31 13:50:12 +0000[diff] [blame]75<p>Separate documents:</p>
76<ul>
Daniel Veillardc6271d22001-10-27 07:50:58 +0000[diff] [blame]77 <li><a href="http://xmlsoft.org/XSLT/">the libxslt page</a>
78 providing an implementation of XSLT 1.0 and extensions on top of
79 libxml2</li>
80 <li><a href="http://www.cs.unibo.it/~casarini/gdome2/">the gdome2 page</a>
Daniel Veillard51095312001-10-28 18:51:57 +0000[diff] [blame]81 : a standard DOM2 implementation based on libxml2</li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]82</ul>
83
84<h2><a name="Introducti">Introduction</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]85
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]86<p>This document describes libxml, the <a
Daniel Veillardec78c0f2000-08-25 10:25:23 +0000[diff] [blame]87href="http://www.w3.org/XML/">XML</a> C library developped for the <a
88href="http://www.gnome.org/">Gnome</a> project. <a
89href="http://www.w3.org/XML/">XML is a standard</a> for building tag-based
90structured documents/data.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]91
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]92<p>Here are some key points about libxml:</p>
93<ul>
Daniel Veillard189446d2000-10-13 10:23:06 +0000[diff] [blame]94 <li>Libxml exports Push and Pull type parser interfaces for both XML and
95 HTML.</li>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]96 <li>Libxml can do DTD validation at parse time, using a parsed document
97 instance, or with an arbitrary DTD.</li>
98 <li>Libxml now includes nearly complete <a
Daniel Veillard8c2ecaf2001-07-10 17:53:07 +0000[diff] [blame]99 href="http://www.w3.org/TR/xpath">XPath</a>, <a
100 href="http://www.w3.org/TR/xptr">XPointer</a> and <a
101 href="http://www.w3.org/TR/xinclude">XInclude</a> implementations.</li>
Daniel Veillardec78c0f2000-08-25 10:25:23 +0000[diff] [blame]102 <li>It is written in plain C, making as few assumptions as possible, and
Daniel Veillard189446d2000-10-13 10:23:06 +0000[diff] [blame]103 sticking closely to ANSI C/POSIX for easy embedding. Works on
Daniel Veillardab8500d2000-10-15 21:06:19 +0000[diff] [blame]104 Linux/Unix/Windows, ported to a number of other platforms.</li>
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]105 <li>Basic support for HTTP and FTP client allowing aplications to fetch
106 remote resources</li>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]107 <li>The design is modular, most of the extensions can be compiled out.</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]108 <li>The internal document repesentation is as close as possible to the <a
109 href="http://www.w3.org/DOM/">DOM</a> interfaces.</li>
110 <li>Libxml also has a <a href="http://www.megginson.com/SAX/index.html">SAX
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]111 like interface</a>; the interface is designed to be compatible with <a
112 href="http://www.jclark.com/xml/expat.html">Expat</a>.</li>
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]113 <li>This library is released both under the <a
114 href="http://www.w3.org/Consortium/Legal/copyright-software-19980720.html">W3C
Daniel Veillard189446d2000-10-13 10:23:06 +0000[diff] [blame]115 IPR</a> and the <a href="http://www.gnu.org/copyleft/lesser.html">GNU
116 LGPL</a>. Use either at your convenience, basically this should make
117 everybody happy, if not, drop me a mail.</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]118</ul>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]119
Daniel Veillarde0c1d722001-03-21 10:28:36 +0000[diff] [blame]120<p>Warning: unless you are forced to because your application links with a
121Gnome library requiring it, <strong><span
122style="background-color: #FF0000">Do Not Use libxml1</span></strong>, use
123libxml2</p>
124
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]125<h2><a name="FAQ">FAQ</a></h2>
126
127<p>Table of Content:</p>
128<ul>
129 <li><a href="FAQ.html#Licence">Licence(s)</a></li>
130 <li><a href="FAQ.html#Installati">Installation</a></li>
131 <li><a href="FAQ.html#Compilatio">Compilation</a></li>
132 <li><a href="FAQ.html#Developer">Developer corner</a></li>
133</ul>
134
135<h3><a name="Licence">Licence</a>(s)</h3>
136<ol>
137 <li><em>Licensing Terms for libxml</em>
138 <p>libxml is released under 2 (compatible) licences:</p>
139 <ul>
140 <li>the <a href="http://www.gnu.org/copyleft/lgpl.html">LGPL</a>: GNU
141 Library General Public License</li>
142 <li>the <a
143 href="http://www.w3.org/Consortium/Legal/copyright-software-19980720.html">W3C
144 IPR</a>: very similar to the XWindow licence</li>
145 </ul>
146 </li>
147 <li><em>Can I embed libxml in a proprietary application ?</em>
148 <p>Yes. The W3C IPR allows you to also keep proprietary the changes you
149 made to libxml, but it would be graceful to provide back bugfixes and
150 improvements as patches for possible incorporation in the main
151 development tree</p>
152 </li>
153</ol>
154
155<h3><a name="Installati">Installation</a></h3>
156<ol>
157 <li>Unless you are forced to because your application links with a Gnome
158 library requiring it, <strong><span style="background-color: #FF0000">Do
159 Not Use libxml1</span></strong>, use libxml2</li>
160 <li><em>Where can I get libxml</em>
161 ?
162 <p>The original distribution comes from <a
163 href="ftp://rpmfind.net/pub/libxml/">rpmfind.net</a> or <a
164 href="ftp://ftp.gnome.org/pub/GNOME/stable/sources/libxml/">gnome.org</a></p>
165 <p>Most linux and Bsd distribution includes libxml, this is probably the
166 safer way for end-users</p>
167 <p>David Doolin provides precompiled Windows versions at <a
168 href="http://www.ce.berkeley.edu/~doolin/code/libxmlwin32/ ">http://www.ce.berkeley.edu/~doolin/code/libxmlwin32/</a></p>
169 </li>
170 <li><em>I see libxml and libxml2 releases, which one should I install ?</em>
171 <ul>
172 <li>If you are not concerned by any existing backward compatibility
173 with existing application, install libxml2 only</li>
174 <li>If you are not doing development, you can safely install both.
175 usually the packages <a
176 href="http://rpmfind.net/linux/RPM/libxml.html">libxml</a> and <a
177 href="http://rpmfind.net/linux/RPM/libxml2.html">libxml2</a> are
178 compatible (this is not the case for development packages)</li>
179 <li>If you are a developer and your system provides separate packaging
180 for shared libraries and the development components, it is possible
181 to install libxml and libxml2, and also <a
182 href="http://rpmfind.net/linux/RPM/libxml-devel.html">libxml-devel</a>
183 and <a
184 href="http://rpmfind.net/linux/RPM/libxml2-devel.html">libxml2-devel</a>
185 too for libxml2 &gt;= 2.3.0</li>
186 <li>If you are developing a new application, please develop against
187 libxml2(-devel)</li>
188 </ul>
189 </li>
190 <li><em>I can't install the libxml package it conflicts with libxml0</em>
191 <p>You probably have an old libxml0 package used to provide the shared
192 library for libxml.so.0, you can probably safely remove it. Anyway the
193 libxml packages provided on <a
194 href="ftp://rpmfind.net/pub/libxml/">rpmfind.net</a> provides
195 libxml.so.0</p>
196 </li>
197 <li><em>I can't install the libxml(2) RPM package due to failed
198 dependancies</em>
199 <p>The most generic solution is to refetch the latest src.rpm , and
200 rebuild it locally with</p>
201 <p><code>rpm --rebuild libxml(2)-xxx.src.rpm</code></p>
202 <p>if everything goes well it will generate two binary rpm (one providing
203 the shared libs and xmllint, and the other one, the -devel package
204 providing includes, static libraries and scripts needed to build
205 applications with libxml(2)) that you can install locally.</p>
206 </li>
207</ol>
208
209<h3><a name="Compilatio">Compilation</a></h3>
210<ol>
211 <li><em>What is the process to compile libxml ?</em>
212 <p>As most UNIX libraries libxml follows the "standard":</p>
213 <p><code>gunzip -c xxx.tar.gz | tar xvf -</code></p>
214 <p><code>cd libxml-xxxx</code></p>
215 <p><code>./configure --help</code></p>
216 <p>to see the options, then the compilation/installation proper</p>
217 <p><code>./configure [possible options]</code></p>
218 <p><code>make</code></p>
219 <p><code>make install</code></p>
220 <p>At that point you may have to rerun ldconfig or similar utility to
221 update your list of installed shared libs.</p>
222 </li>
223 <li><em>What other libraries are needed to compile/install libxml ?</em>
224 <p>Libxml does not requires any other library, the normal C ANSI API
225 should be sufficient (please report any violation to this rule you may
226 find).</p>
227 <p>However if found at configuration time libxml will detect and use the
228 following libs:</p>
229 <ul>
230 <li><a href="http://www.info-zip.org/pub/infozip/zlib/">libz</a>
231 : a highly portable and available widely compression library</li>
232 <li>iconv: a powerful character encoding conversion library. It's
233 included by default on recent glibc libraries, so it doesn't need to
234 be installed specifically on linux. It seems it's now <a
235 href="http://www.opennc.org/onlinepubs/7908799/xsh/iconv.html">part
236 of the official UNIX</a> specification. Here is one <a
237 href="http://clisp.cons.org/~haible/packages-libiconv.html">implementation
238 of the library</a> which source can be found <a
239 href="ftp://ftp.ilog.fr/pub/Users/haible/gnu/">here</a>.</li>
240 </ul>
241 </li>
242 <li><em>libxml does not compile with HP-UX's optional ANSI-C compiler</em>
243 <p>this is due to macro limitations. Try to add " -Wp,-H16800 -Ae" to the
244 CFLAGS</p>
245 <p>you can also install and use gcc instead or use a precompiled version
246 of libxml, both available from the <a
247 href="http://hpux.cae.wisc.edu/hppd/auto/summary_all.html">HP-UX Porting
248 and Archive Centre</a></p>
249 </li>
250 <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
254 diff is small this is probably not a serious problem</p>
255 </li>
256 <li><em>I use the CVS version and there is no configure script</em>
257 <p>The configure (and other Makefiles) are generated. Use the autogen.sh
258 script to regenerate the configure and Makefiles, like:</p>
259 <p><code>./autogen.sh --prefix=/usr --disable-shared</code></p>
260 </li>
261 <li><em>I have troubles when running make tests with gcc-3.0</em>
262 <p>It seems the initial release of gcc-3.0 has a problem with the
263 optimizer which miscompiles the URI module. Please use another
264 compiler</p>
265 </li>
266</ol>
267
268<h3><a name="Developer">Developer</a> corner</h3>
269<ol>
270 <li><em>xmlDocDump() generates output on one line</em>
271 <p>libxml will not <strong>invent</strong> spaces in the content of a
272 document since <strong>all spaces in the content of a document are
273 significant</strong>. If you build a tree from the API and want
274 indentation:</p>
275 <ol>
276 <li>the correct way is to generate those yourself too</li>
277 <li>the dangerous way is to ask libxml to add those blanks to your
278 content <strong>modifying the content of your document in the
279 process</strong>. The result may not be what you expect. There is
280 <strong>NO</strong> way to guarantee that such a modification won't
281 impact other part of the content of your document. See <a
282 href="http://xmlsoft.org/html/libxml-parser.html#XMLKEEPBLANKSDEFAULT">xmlKeepBlanksDefault
283 ()</a> and <a
284 href="http://xmlsoft.org/html/libxml-tree.html#XMLSAVEFORMATFILE">xmlSaveFormatFile
285 ()</a></li>
286 </ol>
287 </li>
288 <li>Extra nodes in the document:
289 <p><em>For a XML file as below:</em></p>
290 <pre>&lt;?xml version="1.0"?&gt;
291&lt;PLAN xmlns="http://www.argus.ca/autotest/1.0/"&gt;
292&lt;NODE CommFlag="0"/&gt;
293&lt;NODE CommFlag="1"/&gt;
294&lt;/PLAN&gt;</pre>
295 <p><em>after parsing it with the function
296 pxmlDoc=xmlParseFile(...);</em></p>
297 <p><em>I want to the get the content of the first node (node with the
298 CommFlag="0")</em></p>
299 <p><em>so I did it as following;</em></p>
300 <pre>xmlNodePtr pode;
301pnode=pxmlDoc-&gt;children-&gt;children;</pre>
302 <p><em>but it does not work. If I change it to</em></p>
303 <pre>pnode=pxmlDoc-&gt;children-&gt;children-&gt;next;</pre>
304 <p><em>then it works. Can someone explain it to me.</em></p>
305 <p></p>
306 <p>In XML all characters in the content of the document are significant
307 <strong>including blanks and formatting line breaks</strong>.</p>
308 <p>The extra nodes you are wondering about are just that, text nodes with
309 the formatting spaces wich are part of the document but that people tend
310 to forget. There is a function <a
311 href="http://xmlsoft.org/html/libxml-parser.html">xmlKeepBlanksDefault
312 ()</a> to remove those at parse time, but that's an heuristic, and its
313 use should be limited to case where you are sure there is no
314 mixed-content in the document.</p>
315 </li>
316 <li><em>I get compilation errors of existing code like when accessing
317 <strong>root</strong> or <strong>childs fields</strong> of nodes</em>
318 <p>You are compiling code developed for libxml version 1 and using a
319 libxml2 development environment. Either switch back to libxml v1 devel or
320 even better fix the code to compile with libxml2 (or both) by <a
321 href="upgrade.html">following the instructions</a>.</p>
322 </li>
323 <li><em>I get compilation errors about non existing
324 <strong>xmlRootNode</strong> or <strong>xmlChildrenNode</strong>
325 fields</em>
326 <p>The source code you are using has been <a
327 href="upgrade.html">upgraded</a> to be able to compile with both libxml
328 and libxml2, but you need to install a more recent version:
329 libxml(-devel) &gt;= 1.8.8 or libxml2(-devel) &gt;= 2.1.0</p>
330 </li>
331 <li><em>XPath implementation looks seriously broken</em>
332 <p>XPath implementation prior to 2.3.0 was really incomplete, upgrade to
333 a recent version, the implementation and debug of libxslt generated fixes
334 for most obvious problems.</p>
335 </li>
336 <li><em>The example provided in the web page does not compile</em>
337 <p>It's hard to maintain the documentation in sync with the code
338 &lt;grin/&gt; ...</p>
339 <p>Check the previous points 1/ and 2/ raised before, and send
340 patches.</p>
341 </li>
342 <li><em>Where can I get more examples and informations than in the web
343 page</em>
344 <p>Ideally a libxml book would be nice. I have no such plan ... But you
345 can:</p>
346 <ul>
347 <li>check more deeply the <a href="html/libxml-lib.html">existing
348 generated doc</a></li>
349 <li>looks for examples of use for libxml function using the Gnome code
350 for example the following will query the full Gnome CVs base for the
351 use of the <strong>xmlAddChild()</strong> function:
352 <p><a
353 href="http://cvs.gnome.org/lxr/search?string=xmlAddChild">http://cvs.gnome.org/lxr/search?string=xmlAddChild</a></p>
354 <p>This may be slow, a large hardware donation to the gnome project
355 could cure this :-)</p>
356 </li>
357 <li><a
358 href="http://cvs.gnome.org/bonsai/rview.cgi?cvsroot=/cvs/gnome&amp;dir=gnome-xml">Browse
359 the libxml source</a>
360 , I try to write code as clean and documented as possible, so
361 looking at it may be helpful</li>
362 </ul>
363 </li>
364 <li>What about C++ ?
365 <p>libxml is written in pure C in order to allow easy reuse on a number
366 of platforms, including embedded systems. I don't intend to convert to
367 C++.</p>
368 <p>There is however a C++ wrapper provided by Ari Johnson
369 &lt;ari@btigate.com&gt; which may fullfill your needs:</p>
370 <p>Website: <a
371 href="http://lusis.org/~ari/xml++/">http://lusis.org/~ari/xml++/</a></p>
372 <p>Download: <a
373 href="http://lusis.org/~ari/xml++/libxml++.tar.gz">http://lusis.org/~ari/xml++/libxml++.tar.gz</a></p>
374 </li>
375 <li>How to validate a document a posteriori ?
376 <p>It is possible to validate documents which had not been validated at
377 initial parsing time or documents who have been built from scratch using
378 the API. Use the <a
379 href="http://xmlsoft.org/html/libxml-valid.html#XMLVALIDATEDTD">xmlValidateDtd()</a>
380 function. It is also possible to simply add a Dtd to an existing
381 document:</p>
382 <pre>xmlDocPtr doc; /* your existing document */
383 xmlDtdPtr dtd = xmlParseDTD(NULL, filename_of_dtd); /* parse the DTD */
384 dtd-&gt;name = xmlStrDup((xmlChar*)"root_name"); /* use the given root */
385
386 doc-&gt;intSubset = dtd;
387 if (doc-&gt;children == NULL) xmlAddChild((xmlNodePtr)doc, (xmlNodePtr)dtd);
388 else xmlAddPrevSibling(doc-&gt;children, (xmlNodePtr)dtd);
389 </pre>
390 </li>
391 <li>etc ...</li>
392</ol>
393
394<p></p>
395
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]396<h2><a name="Documentat">Documentation</a></h2>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]397
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]398<p>There are some on-line resources about using libxml:</p>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]399<ol>
Daniel Veillard365e13b2000-07-02 07:56:37 +0000[diff] [blame]400 <li>Check the <a href="FAQ.html">FAQ</a></li>
Daniel Veillardc19fccc2000-07-03 11:52:01 +0000[diff] [blame]401 <li>Check the <a href="http://xmlsoft.org/html/libxml-lib.html">extensive
Daniel Veillard8c6d6af2000-08-25 17:14:13 +0000[diff] [blame]402 documentation</a> automatically extracted from code comments (using <a
403 href="http://cvs.gnome.org/bonsai/rview.cgi?cvsroot=/cvs/gnome&amp;dir=gtk-doc">gtk
404 doc</a>).</li>
Daniel Veillard8d869642000-07-14 12:12:59 +0000[diff] [blame]405 <li>Look at the documentation about <a href="encoding.html">libxml
406 internationalization support</a></li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]407 <li>This page provides a global overview and <a href="#real">some
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]408 examples</a> on how to use libxml.</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]409 <li><a href="mailto:james@daa.com.au">James Henstridge</a>
410 wrote <a
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]411 href="http://www.daa.com.au/~james/gnome/xml-sax/xml-sax.html">some nice
412 documentation</a> explaining how to use the libxml SAX interface.</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]413 <li>George Lebl wrote <a
414 href="http://www-4.ibm.com/software/developer/library/gnome3/">an article
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]415 for IBM developerWorks</a> about using libxml.</li>
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]416 <li>Check <a href="http://cvs.gnome.org/lxr/source/gnome-xml/TODO">the TODO
417 file</a></li>
418 <li>Read the <a href="upgrade.html">1.x to 2.x upgrade path</a>. If you are
419 starting a new project using libxml you should really use the 2.x
420 version.</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]421 <li>And don't forget to look at the <a href="/messages/">mailing-list
Daniel Veillardc310d562000-06-23 18:32:15 +0000[diff] [blame]422 archive</a>.</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]423</ol>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]424
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]425<h2><a name="Reporting">Reporting bugs and getting help</a></h2>
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000[diff] [blame]426
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]427<p>Well, bugs or missing features are always possible, and I will make a
428point of fixing them in a timely fashion. The best way to report a bug is to
429use the <a href="http://bugzilla.gnome.org/buglist.cgi?product=libxml">Gnome
430bug tracking database</a> (make sure to use the "libxml" module name). I look
431at reports there regularly and it's good to have a reminder when a bug is
Daniel Veillard51095312001-10-28 18:51:57 +0000[diff] [blame]432still open. Be sure to specify that the bug is for the package libxml.</p>
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000[diff] [blame]433
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]434<p>There is also a mailing-list <a
Daniel Veillard3197f162001-04-04 00:40:08 +0000[diff] [blame]435href="mailto:xml@gnome.org">xml@gnome.org</a> for libxml, with an <a
436href="http://mail.gnome.org/archives/xml/">on-line archive</a> (<a
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]437href="http://xmlsoft.org/messages">old</a>). To subscribe to this list,
438please visit the <a
439href="http://mail.gnome.org/mailman/listinfo/xml">associated Web</a> page and
440follow the instructions. <strong>Do not send code, I won't debug it</strong>
441(but patches are really appreciated!).</p>
Daniel Veillard234547b2001-07-05 09:46:10 +0000[diff] [blame]442
Daniel Veillard008186f2001-09-13 14:24:44 +0000[diff] [blame]443<p>Check the following <strong><span style="color: #FF0000">before
444posting</span></strong>:</p>
Daniel Veillard234547b2001-07-05 09:46:10 +0000[diff] [blame]445<ul>
Daniel Veillarddadd0872001-09-15 09:21:44 +0000[diff] [blame]446 <li>read the <a href="FAQ.html">FAQ</a></li>
Daniel Veillard234547b2001-07-05 09:46:10 +0000[diff] [blame]447 <li>make sure you are <a href="ftp://xmlsoft.org/">using a recent
448 version</a>, and that the problem still shows up in those</li>
449 <li>check the <a href="http://mail.gnome.org/archives/xml/">list
450 archives</a> to see if the problem was reported already, in this case
Daniel Veillarde7ead2d2001-08-22 23:44:09 +0000[diff] [blame]451 there is probably a fix available, similary check the <a
452 href="http://bugzilla.gnome.org/buglist.cgi?product=libxml">registered
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]453 open bugs</a></li>
Daniel Veillard234547b2001-07-05 09:46:10 +0000[diff] [blame]454 <li>make sure you can reproduce the bug with xmllint or one of the test
455 programs found in source in the distribution</li>
456 <li>Please send the command showing the error as well as the input (as an
457 attachement)</li>
458</ul>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]459
Daniel Veillarddadd0872001-09-15 09:21:44 +0000[diff] [blame]460<p>Then send the bug with associated informations to reproduce it to the <a
Daniel Veillard33a67802001-03-07 09:44:02 +0000[diff] [blame]461href="mailto:xml@gnome.org">xml@gnome.org</a> list; if it's really libxml
Daniel Veillard008186f2001-09-13 14:24:44 +0000[diff] [blame]462related I will approve it.. Please do not send me mail directly, it makes
463things really harder to track and in some cases I'm not the best person to
464answer a given question, ask the list instead.</p>
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000[diff] [blame]465
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]466<p>Of course, bugs reported with a suggested patch for fixing them will
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]467probably be processed faster.</p>
468
469<p>If you're looking for help, a quick look at <a
Daniel Veillardf7ed3362001-08-17 12:01:21 +0000[diff] [blame]470href="http://mail.gnome.org/archives/xml/">the list archive</a> may actually
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]471provide the answer, I usually send source samples when answering libxml usage
Daniel Veillard6f0adb52000-07-03 11:41:26 +0000[diff] [blame]472questions. The <a href="http://xmlsoft.org/html/book1.html">auto-generated
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]473documentantion</a> is not as polished as I would like (i need to learn more
474about Docbook), but it's a good starting point.</p>
475
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]476<h2><a name="help">How to help</a></h2>
477
478<p>You can help the project in various ways, the best thing to do first is to
479subscribe to the mailing-list as explained before, check the <a
Daniel Veillardf7ed3362001-08-17 12:01:21 +0000[diff] [blame]480href="http://mail.gnome.org/archives/xml/">archives </a>and the <a
481href="http://bugzilla.gnome.org/buglist.cgi?product=libxml">Gnome bug
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]482database:</a>:</p>
483<ol>
484 <li>provide patches when you find problems</li>
Daniel Veillard189446d2000-10-13 10:23:06 +0000[diff] [blame]485 <li>provide the diffs when you port libxml to a new platform. They may not
Daniel Veillardab8500d2000-10-15 21:06:19 +0000[diff] [blame]486 be integrated in all cases but help pinpointing portability problems
487 and</li>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]488 <li>provide documentation fixes (either as patches to the code comments or
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]489 as HTML diffs).</li>
490 <li>provide new documentations pieces (translations, examples, etc ...)</li>
491 <li>Check the TODO file and try to close one of the items</li>
492 <li>take one of the points raised in the archive or the bug database and
Daniel Veillarde7ead2d2001-08-22 23:44:09 +0000[diff] [blame]493 provide a fix. <a href="mailto:daniel@veillard.com">Get in touch with me
494 </a>before to avoid synchronization problems and check that the suggested
495 fix will fit in nicely :-)</li>
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]496</ol>
497
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]498<h2><a name="Downloads">Downloads</a></h2>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]499
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]500<p>The latest versions of libxml can be found on <a
Daniel Veillard20c8cf22001-06-26 22:47:36 +0000[diff] [blame]501href="ftp://xmlsoft.org/">xmlsoft.org</a> (<a
502href="ftp://speakeasy.rpmfind.net/pub/libxml/">Seattle</a>, <a
503href="ftp://fr.rpmfind.net/pub/libxml/">France</a>) or on the <a
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]504href="ftp://ftp.gnome.org/pub/GNOME/MIRRORS.html">Gnome FTP server</a> either
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]505as a <a href="ftp://ftp.gnome.org/pub/GNOME/stable/sources/libxml/">source
Daniel Veillard306be992000-07-03 12:38:45 +0000[diff] [blame]506archive</a> or <a
Daniel Veillarda41123c2001-04-22 19:31:20 +0000[diff] [blame]507href="ftp://ftp.gnome.org/pub/GNOME/stable/redhat/i386/libxml/">RPM
508packages</a>. (NOTE that you need both the <a
Daniel Veillardc19fccc2000-07-03 11:52:01 +0000[diff] [blame]509href="http://rpmfind.net/linux/RPM/libxml2.html">libxml(2)</a> and <a
510href="http://rpmfind.net/linux/RPM/libxml2-devel.html">libxml(2)-devel</a>
Daniel Veillard95189532001-07-26 18:30:26 +0000[diff] [blame]511packages installed to compile applications using libxml.) <a
512href="mailto:izlatkovic@daenet.de">Igor Zlatkovic</a> is now the maintainer
513of the Windows port, <a
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]514href="http://www.fh-frankfurt.de/~igor/projects/libxml/index.html">he
Daniel Veillardc6271d22001-10-27 07:50:58 +0000[diff] [blame]515provides binaries</a>. <a href="mailto:Gary.Pennington@sun.com">Gary
Daniel Veillard1aadc442001-11-28 13:10:32 +0000[diff] [blame]516Pennington</a> provides <a href="http://garypennington.net/libxml2/">Solaris
517binaries</a>.</p>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]518
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]519<p><a name="Snapshot">Snapshot:</a></p>
520<ul>
521 <li>Code from the W3C cvs base libxml <a
Daniel Veillard33a67802001-03-07 09:44:02 +0000[diff] [blame]522 href="ftp://xmlsoft.org/cvs-snapshot.tar.gz">cvs-snapshot.tar.gz</a></li>
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]523 <li>Docs, content of the web site, the list archive included <a
Daniel Veillard33a67802001-03-07 09:44:02 +0000[diff] [blame]524 href="ftp://xmlsoft.org/libxml-docs.tar.gz">libxml-docs.tar.gz</a></li>
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]525</ul>
526
Daniel Veillardc6271d22001-10-27 07:50:58 +0000[diff] [blame]527<p><a name="Contribs">Contributions:</a></p>
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]528
529<p>I do accept external contributions, especially if compiling on another
Daniel Veillardc6271d22001-10-27 07:50:58 +0000[diff] [blame]530platform, get in touch with me to upload the package, wrappers for various
Daniel Veillard51095312001-10-28 18:51:57 +0000[diff] [blame]531languages have been provided, and can be found in the <a
532href="contribs.html">contrib section</a></p>
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]533
Daniel Veillard82687162001-01-22 15:32:01 +0000[diff] [blame]534<p>Libxml is also available from CVS:</p>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]535<ul>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]536 <li><p>The <a
537 href="http://cvs.gnome.org/bonsai/rview.cgi?cvsroot=/cvs/gnome&amp;dir=gnome-xml">Gnome
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]538 CVS base</a>. Check the <a
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]539 href="http://developer.gnome.org/tools/cvs.html">Gnome CVS Tools</a>
540 page; the CVS module is <b>gnome-xml</b>.</p>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]541 </li>
Daniel Veillard82687162001-01-22 15:32:01 +0000[diff] [blame]542 <li>The <strong>libxslt</strong> module is also present there</li>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]543</ul>
544
545<h2><a name="News">News</a></h2>
546
Daniel Veillard944b5ff1999-12-15 19:08:24 +0000[diff] [blame]547<h3>CVS only : check the <a
548href="http://cvs.gnome.org/lxr/source/gnome-xml/ChangeLog">Changelog</a> file
Daniel Veillard189446d2000-10-13 10:23:06 +0000[diff] [blame]549for a really accurate description</h3>
Daniel Veillardab8500d2000-10-15 21:06:19 +0000[diff] [blame]550
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]551<p>Items floating around but not actively worked on, get in touch with me if
Daniel Veillardab8500d2000-10-15 21:06:19 +0000[diff] [blame]552you want to test those</p>
553<ul>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]554 <li>Implementing <a href="http://xmlsoft.org/XSLT">XSLT</a>, this is done
555 as a separate C library on top of libxml called libxslt</li>
Daniel Veillard28929b22000-11-13 18:22:49 +0000[diff] [blame]556 <li>Finishing up <a href="http://www.w3.org/TR/xptr">XPointer</a> and <a
557 href="http://www.w3.org/TR/xinclude">XInclude</a></li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]558 <li>(seeems working but delayed from release) parsing/import of Docbook
559 SGML docs</li>
560</ul>
561
Daniel Veillardef90ba72001-12-07 14:24:22 +0000[diff] [blame^]562<h3>2.4.12: Dec 7 2001</h3>
563<ul>
564 <li>a few bug fixes: thread (Gary Pennington), xmllint (Geert Kloosterman),
565 XML parser (Robin Berjon), XPointer (Danny Jamshy), I/O cleanups
566 (robert)</li>
567 <li>Eric Lavigne contributed project files for MacOS</li>
568 <li>some makefiles cleanups</li>
569</ul>
570
Daniel Veillarda4871052001-11-26 13:19:48 +0000[diff] [blame]571<h3>2.4.11: Nov 26 2001</h3>
572<ul>
573 <li>fixed a couple of errors in the includes, fixed a few bugs, some code
574 cleanups</li>
575 <li>xmllint man pages improvement by Heiko Rupp</li>
576 <li>updated VMS build instructions from John A Fotheringham</li>
577 <li>Windows Makefiles updates from Igor</li>
578</ul>
579
Daniel Veillard43d3f612001-11-10 11:57:23 +0000[diff] [blame]580<h3>2.4.10: Nov 10 2001</h3>
581<ul>
582 <li>URI escaping fix (Joel Young)</li>
583 <li>added xmlGetNodePath() (for paths or XPointers generation)</li>
584 <li>Fixes namespace handling problems when using DTD and validation</li>
585 <li>improvements on xmllint: Morus Walter patches for --format and
586 --encode, Stefan Kost and Heiko Rupp improvements on the --shell</li>
587 <li>fixes for xmlcatalog linking pointed by Weiqi Gao</li>
588 <li>fixes to the HTML parser</li>
589</ul>
590
591<h3>2.4.9: Nov 6 2001</h3>
592<ul>
593 <li>fixes more catalog bugs</li>
594 <li>avoid a compilation problem, improve xmlGetLineNo()</li>
595</ul>
596
Daniel Veillarded421aa2001-11-04 21:22:45 +0000[diff] [blame]597<h3>2.4.8: Nov 4 2001</h3>
598<ul>
599 <li>fixed SGML catalogs broken in previous release, updated xmlcatalog
600 tool</li>
601 <li>fixed a compile errors and some includes troubles.</li>
602</ul>
603
Daniel Veillard52dcab32001-10-30 12:51:17 +0000[diff] [blame]604<h3>2.4.7: Oct 30 2001</h3>
605<ul>
606 <li>exported some debugging interfaces</li>
607 <li>serious rewrite of the catalog code</li>
608 <li>integrated Gary Pennington thread safety patch, added configure option
609 and regression tests</li>
610 <li>removed an HTML parser bug</li>
611 <li>fixed a couple of potentially serious validation bugs</li>
612 <li>integrated the SGML DocBook support in xmllint</li>
613 <li>changed the nanoftp anonymous login passwd</li>
614 <li>some I/O cleanup and a couple of interfaces for Perl wrapper</li>
615 <li>general bug fixes</li>
616 <li>updated xmllint man page by John Fleck</li>
617 <li>some VMS and Windows updates</li>
618</ul>
619
Daniel Veillard60087f32001-10-10 09:45:09 +0000[diff] [blame]620<h3>2.4.6: Oct 10 2001</h3>
621<ul>
Daniel Veillard52dcab32001-10-30 12:51:17 +0000[diff] [blame]622 <li>added an updated man pages by John Fleck</li>
Daniel Veillard60087f32001-10-10 09:45:09 +0000[diff] [blame]623 <li>portability and configure fixes</li>
624 <li>an infinite loop on the HTML parser was removed (William)</li>
625 <li>Windows makefile patches from Igor</li>
626 <li>fixed half a dozen bugs reported fof libxml or libxslt</li>
627 <li>updated xmlcatalog to be able to modify SGML super catalogs</li>
628</ul>
629
Daniel Veillarddadd0872001-09-15 09:21:44 +0000[diff] [blame]630<h3>2.4.5: Sep 14 2001</h3>
631<ul>
632 <li>Remove a few annoying bugs in 2.4.4</li>
633 <li>forces the HTML serializer to output decimal charrefs since some
634 version of Netscape can't handle hexadecimal ones</li>
635</ul>
636
637<h3>1.8.16: Sep 14 2001</h3>
638<ul>
639 <li>maintenance release of the old libxml1 branch, couple of bug and
640 portability fixes</li>
641</ul>
642
Daniel Veillard04382ae2001-09-12 18:51:30 +0000[diff] [blame]643<h3>2.4.4: Sep 12 2001</h3>
644<ul>
645 <li>added --convert to xmlcatalog, bug fixes and cleanups of XML
646 Catalog</li>
647 <li>a few bug fixes and some portability changes</li>
648 <li>some documentation cleanups</li>
649</ul>
650
Daniel Veillard39936902001-08-24 00:49:01 +0000[diff] [blame]651<h3>2.4.3: Aug 23 2001</h3>
652<ul>
653 <li>XML Catalog support see the doc</li>
654 <li>New NaN/Infinity floating point code</li>
655 <li>A few bug fixes</li>
656</ul>
657
658<h3>2.4.2: Aug 15 2001</h3>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]659<ul>
660 <li>adds xmlLineNumbersDefault() to control line number generation</li>
661 <li>lot of bug fixes</li>
662 <li>the Microsoft MSC projects files shuld now be up to date</li>
663 <li>inheritance of namespaces from DTD defaulted attributes</li>
664 <li>fixes a serious potential security bug</li>
665 <li>added a --format option to xmllint</li>
666</ul>
667
668<h3>2.4.1: July 24 2001</h3>
669<ul>
670 <li>possibility to keep line numbers in the tree</li>
671 <li>some computation NaN fixes</li>
672 <li>extension of the XPath API</li>
673 <li>cleanup for alpha and ia64 targets</li>
674 <li>patch to allow saving through HTTP PUT or POST</li>
Daniel Veillard09ab7e12001-07-10 15:49:44 +0000[diff] [blame]675</ul>
676
677<h3>2.4.0: July 10 2001</h3>
678<ul>
679 <li>Fixed a few bugs in XPath, validation, and tree handling.</li>
680 <li>Fixed XML Base implementation, added a coupel of examples to the
681 regression tests</li>
682 <li>A bit of cleanup</li>
Daniel Veillardab8500d2000-10-15 21:06:19 +0000[diff] [blame]683</ul>
684
Daniel Veillard5b43fde2001-07-05 23:31:40 +0000[diff] [blame]685<h3>2.3.14: July 5 2001</h3>
686<ul>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]687 <li>fixed some entities problems and reduce mem requirement when
688 substituing them</li>
Daniel Veillard5b43fde2001-07-05 23:31:40 +0000[diff] [blame]689 <li>lots of improvements in the XPath queries interpreter can be
690 substancially faster</li>
691 <li>Makefiles and configure cleanups</li>
692 <li>Fixes to XPath variable eval, and compare on empty node set</li>
693 <li>HTML tag closing bug fixed</li>
694 <li>Fixed an URI reference computating problem when validating</li>
695</ul>
696
Daniel Veillard2adbb512001-06-28 16:20:36 +0000[diff] [blame]697<h3>2.3.13: June 28 2001</h3>
698<ul>
699 <li>2.3.12 configure.in was broken as well as the push mode XML parser</li>
700 <li>a few more fixes for compilation on Windows MSC by Yon Derek</li>
701</ul>
702
703<h3>1.8.14: June 28 2001</h3>
704<ul>
705 <li>Zbigniew Chyla gave a patch to use the old XML parser in push mode</li>
706 <li>Small Makefile fix</li>
707</ul>
708
Daniel Veillard11648102001-06-26 16:08:24 +0000[diff] [blame]709<h3>2.3.12: June 26 2001</h3>
710<ul>
711 <li>lots of cleanup</li>
712 <li>a couple of validation fix</li>
713 <li>fixed line number counting</li>
714 <li>fixed serious problems in the XInclude processing</li>
715 <li>added support for UTF8 BOM at beginning of entities</li>
716 <li>fixed a strange gcc optimizer bugs in xpath handling of float, gcc-3.0
717 miscompile uri.c (William), Thomas Leitner provided a fix for the
718 optimizer on Tru64</li>
719 <li>incorporated Yon Derek and Igor Zlatkovic fixes and improvements for
720 compilation on Windows MSC</li>
721 <li>update of libxml-doc.el (Felix Natter)</li>
722 <li>fixed 2 bugs in URI normalization code</li>
723</ul>
724
Daniel Veillarde3c81b52001-06-17 14:50:34 +0000[diff] [blame]725<h3>2.3.11: June 17 2001</h3>
726<ul>
727 <li>updates to trio, Makefiles and configure should fix some portability
728 problems (alpha)</li>
729 <li>fixed some HTML serialization problems (pre, script, and block/inline
730 handling), added encoding aware APIs, cleanup of this code</li>
731 <li>added xmlHasNsProp()</li>
732 <li>implemented a specific PI for encoding support in the DocBook SGML
733 parser</li>
734 <li>some XPath fixes (-Infinity, / as a function parameter and namespaces
735 node selection)</li>
736 <li>fixed a performance problem and an error in the validation code</li>
737 <li>fixed XInclude routine to implement the recursive behaviour</li>
738 <li>fixed xmlFreeNode problem when libxml is included statically twice</li>
739 <li>added --version to xmllint for bug reports</li>
740</ul>
741
Daniel Veillard2e4f1882001-06-01 10:11:57 +0000[diff] [blame]742<h3>2.3.10: June 1 2001</h3>
743<ul>
744 <li>fixed the SGML catalog support</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]745 <li>a number of reported bugs got fixed, in XPath, iconv detection,
746 XInclude processing</li>
Daniel Veillard2e4f1882001-06-01 10:11:57 +0000[diff] [blame]747 <li>XPath string function should now handle unicode correctly</li>
748</ul>
749
Daniel Veillard4623acd2001-05-19 15:13:15 +0000[diff] [blame]750<h3>2.3.9: May 19 2001</h3>
751
752<p>Lots of bugfixes, and added a basic SGML catalog support:</p>
753<ul>
754 <li>HTML push bugfix #54891 and another patch from Jonas Borgström</li>
755 <li>some serious speed optimisation again</li>
756 <li>some documentation cleanups</li>
757 <li>trying to get better linking on solaris (-R)</li>
758 <li>XPath API cleanup from Thomas Broyer</li>
759 <li>Validation bug fixed #54631, added a patch from Gary Pennington, fixed
760 xmlValidGetValidElements()</li>
761 <li>Added an INSTALL file</li>
762 <li>Attribute removal added to API: #54433</li>
763 <li>added a basic support for SGML catalogs</li>
764 <li>fixed xmlKeepBlanksDefault(0) API</li>
765 <li>bugfix in xmlNodeGetLang()</li>
766 <li>fixed a small configure portability problem</li>
767 <li>fixed an inversion of SYSTEM and PUBLIC identifier in HTML document</li>
768</ul>
769
Daniel Veillarda265af72001-05-14 11:13:58 +0000[diff] [blame]770<h3>1.8.13: May 14 2001</h3>
771<ul>
772 <li>bugfixes release of the old libxml1 branch used by Gnome</li>
773</ul>
774
Daniel Veillard3bbbe6f2001-05-03 11:15:37 +0000[diff] [blame]775<h3>2.3.8: May 3 2001</h3>
776<ul>
777 <li>Integrated an SGML DocBook parser for the Gnome project</li>
778 <li>Fixed a few things in the HTML parser</li>
779 <li>Fixed some XPath bugs raised by XSLT use, tried to fix the floating
780 point portability issue</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]781 <li>Speed improvement (8M/s for SAX, 3M/s for DOM, 1.5M/s for
782 DOM+validation using the XML REC as input and a 700MHz celeron).</li>
Daniel Veillard3bbbe6f2001-05-03 11:15:37 +0000[diff] [blame]783 <li>incorporated more Windows cleanup</li>
784 <li>added xmlSaveFormatFile()</li>
785 <li>fixed problems in copying nodes with entities references (gdome)</li>
786 <li>removed some troubles surrounding the new validation module</li>
787</ul>
788
Daniel Veillarda41123c2001-04-22 19:31:20 +0000[diff] [blame]789<h3>2.3.7: April 22 2001</h3>
790<ul>
791 <li>lots of small bug fixes, corrected XPointer</li>
792 <li>Non determinist content model validation support</li>
793 <li>added xmlDocCopyNode for gdome2</li>
794 <li>revamped the way the HTML parser handles end of tags</li>
795 <li>XPath: corrctions of namespacessupport and number formatting</li>
796 <li>Windows: Igor Zlatkovic patches for MSC compilation</li>
797 <li>HTML ouput fixes from P C Chow and William M. Brack</li>
798 <li>Improved validation speed sensible for DocBook</li>
799 <li>fixed a big bug with ID declared in external parsed entities</li>
800 <li>portability fixes, update of Trio from Bjorn Reese</li>
801</ul>
802
Daniel Veillardafc73112001-04-11 11:51:41 +0000[diff] [blame]803<h3>2.3.6: April 8 2001</h3>
804<ul>
805 <li>Code cleanup using extreme gcc compiler warning options, found and
806 cleared half a dozen potential problem</li>
807 <li>the Eazel team found an XML parser bug</li>
808 <li>cleaned up the user of some of the string formatting function. used the
809 trio library code to provide the one needed when the platform is missing
810 them</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]811 <li>xpath: removed a memory leak and fixed the predicate evaluation
812 problem, extended the testsuite and cleaned up the result. XPointer seems
813 broken ...</li>
Daniel Veillardafc73112001-04-11 11:51:41 +0000[diff] [blame]814</ul>
815
Daniel Veillard56a4cb82001-03-24 17:00:36 +0000[diff] [blame]816<h3>2.3.5: Mar 23 2001</h3>
817<ul>
818 <li>Biggest change is separate parsing and evaluation of XPath expressions,
819 there is some new APIs for this too</li>
820 <li>included a number of bug fixes(XML push parser, 51876, notations,
821 52299)</li>
822 <li>Fixed some portability issues</li>
823</ul>
824
Daniel Veillarde356c282001-03-10 12:32:04 +0000[diff] [blame]825<h3>2.3.4: Mar 10 2001</h3>
826<ul>
827 <li>Fixed bugs #51860 and #51861</li>
828 <li>Added a global variable xmlDefaultBufferSize to allow default buffer
829 size to be application tunable.</li>
830 <li>Some cleanup in the validation code, still a bug left and this part
831 should probably be rewritten to support ambiguous content model :-\</li>
832 <li>Fix a couple of serious bugs introduced or raised by changes in 2.3.3
833 parser</li>
834 <li>Fixed another bug in xmlNodeGetContent()</li>
835 <li>Bjorn fixed XPath node collection and Number formatting</li>
836 <li>Fixed a loop reported in the HTML parsing</li>
837 <li>blank space are reported even if the Dtd content model proves that they
838 are formatting spaces, this is for XmL conformance</li>
839</ul>
840
Daniel Veillardb402c072001-03-01 17:28:58 +0000[diff] [blame]841<h3>2.3.3: Mar 1 2001</h3>
842<ul>
843 <li>small change in XPath for XSLT</li>
844 <li>documentation cleanups</li>
845 <li>fix in validation by Gary Pennington</li>
846 <li>serious parsing performances improvements</li>
847</ul>
848
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]849<h3>2.3.2: Feb 24 2001</h3>
Daniel Veillard71681102001-02-24 17:48:53 +0000[diff] [blame]850<ul>
851 <li>chasing XPath bugs, found a bunch, completed some TODO</li>
852 <li>fixed a Dtd parsing bug</li>
853 <li>fixed a bug in xmlNodeGetContent</li>
854 <li>ID/IDREF support partly rewritten by Gary Pennington</li>
855</ul>
856
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]857<h3>2.3.1: Feb 15 2001</h3>
Daniel Veillard6e6a6cc2001-02-15 15:55:44 +0000[diff] [blame]858<ul>
859 <li>some XPath and HTML bug fixes for XSLT</li>
860 <li>small extension of the hash table interfaces for DOM gdome2
861 implementation</li>
862 <li>A few bug fixes</li>
863</ul>
864
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]865<h3>2.3.0: Feb 8 2001 (2.2.12 was on 25 Jan but I didn't kept track)</h3>
Daniel Veillard6e6a6cc2001-02-15 15:55:44 +0000[diff] [blame]866<ul>
867 <li>Lots of XPath bug fixes</li>
868 <li>Add a mode with Dtd lookup but without validation error reporting for
869 XSLT</li>
870 <li>Add support for text node without escaping (XSLT)</li>
871 <li>bug fixes for xmlCheckFilename</li>
872 <li>validation code bug fixes from Gary Pennington</li>
873 <li>Patch from Paul D. Smith correcting URI path normalization</li>
874 <li>Patch to allow simultaneous install of libxml-devel and
875 libxml2-devel</li>
876 <li>the example Makefile is now fixed</li>
877 <li>added HTML to the RPM packages</li>
878 <li>tree copying bugfixes</li>
879 <li>updates to Windows makefiles</li>
880 <li>optimisation patch from Bjorn Reese</li>
881</ul>
882
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]883<h3>2.2.11: Jan 4 2001</h3>
Daniel Veillard503b8932001-01-05 06:36:31 +0000[diff] [blame]884<ul>
885 <li>bunch of bug fixes (memory I/O, xpath, ftp/http, ...)</li>
886 <li>added htmlHandleOmittedElem()</li>
887 <li>Applied Bjorn Reese's IPV6 first patch</li>
888 <li>Applied Paul D. Smith patches for validation of XInclude results</li>
Daniel Veillard82687162001-01-22 15:32:01 +0000[diff] [blame]889 <li>added XPointer xmlns() new scheme support</li>
Daniel Veillard503b8932001-01-05 06:36:31 +0000[diff] [blame]890</ul>
891
Daniel Veillard2ddd23d2000-11-25 10:42:19 +0000[diff] [blame]892<h3>2.2.10: Nov 25 2000</h3>
Daniel Veillard9d343c42000-11-25 10:12:43 +0000[diff] [blame]893<ul>
894 <li>Fix the Windows problems of 2.2.8</li>
895 <li>integrate OpenVMS patches</li>
896 <li>better handling of some nasty HTML input</li>
897 <li>Improved the XPointer implementation</li>
898 <li>integrate a number of provided patches</li>
899</ul>
900
Daniel Veillard2ddd23d2000-11-25 10:42:19 +0000[diff] [blame]901<h3>2.2.9: Nov 25 2000</h3>
902<ul>
903 <li>erroneous release :-(</li>
904</ul>
905
Daniel Veillard28929b22000-11-13 18:22:49 +0000[diff] [blame]906<h3>2.2.8: Nov 13 2000</h3>
907<ul>
908 <li>First version of <a href="http://www.w3.org/TR/xinclude">XInclude</a>
909 support</li>
910 <li>Patch in conditional section handling</li>
911 <li>updated MS compiler project</li>
912 <li>fixed some XPath problems</li>
913 <li>added an URI escaping function</li>
914 <li>some other bug fixes</li>
915</ul>
916
917<h3>2.2.7: Oct 31 2000</h3>
918<ul>
919 <li>added message redirection</li>
920 <li>XPath improvements (thanks TOM !)</li>
921 <li>xmlIOParseDTD() added</li>
922 <li>various small fixes in the HTML, URI, HTTP and XPointer support</li>
923 <li>some cleanup of the Makefile, autoconf and the distribution content</li>
924</ul>
925
Daniel Veillard29a11cc2000-10-25 13:32:39 +0000[diff] [blame]926<h3>2.2.6: Oct 25 2000:</h3>
927<ul>
928 <li>Added an hash table module, migrated a number of internal structure to
929 those</li>
930 <li>Fixed a posteriori validation problems</li>
931 <li>HTTP module cleanups</li>
932 <li>HTML parser improvements (tag errors, script/style handling, attribute
933 normalization)</li>
934 <li>coalescing of adjacent text nodes</li>
935 <li>couple of XPath bug fixes, exported the internal API</li>
936</ul>
937
Daniel Veillardab8500d2000-10-15 21:06:19 +0000[diff] [blame]938<h3>2.2.5: Oct 15 2000:</h3>
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000[diff] [blame]939<ul>
Daniel Veillard189446d2000-10-13 10:23:06 +0000[diff] [blame]940 <li>XPointer implementation and testsuite</li>
941 <li>Lot of XPath fixes, added variable and functions registration, more
942 tests</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]943 <li>Portability fixes, lots of enhancements toward an easy Windows build
944 and release</li>
Daniel Veillard189446d2000-10-13 10:23:06 +0000[diff] [blame]945 <li>Late validation fixes</li>
946 <li>Integrated a lot of contributed patches</li>
947 <li>added memory management docs</li>
Daniel Veillardab8500d2000-10-15 21:06:19 +0000[diff] [blame]948 <li>a performance problem when using large buffer seems fixed</li>
Daniel Veillard189446d2000-10-13 10:23:06 +0000[diff] [blame]949</ul>
950
951<h3>2.2.4: Oct 1 2000:</h3>
952<ul>
953 <li>main XPath problem fixed</li>
954 <li>Integrated portability patches for Windows</li>
955 <li>Serious bug fixes on the URI and HTML code</li>
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]956</ul>
957
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]958<h3>2.2.3: Sep 17 2000</h3>
959<ul>
960 <li>bug fixes</li>
961 <li>cleanup of entity handling code</li>
962 <li>overall review of all loops in the parsers, all sprintf usage has been
963 checked too</li>
964 <li>Far better handling of larges Dtd. Validating against Docbook XML Dtd
965 works smoothly now.</li>
966</ul>
967
968<h3>1.8.10: Sep 6 2000</h3>
969<ul>
970 <li>bug fix release for some Gnome projects</li>
971</ul>
972
973<h3>2.2.2: August 12 2000</h3>
Daniel Veillard786d7c82000-08-12 23:38:57 +0000[diff] [blame]974<ul>
975 <li>mostly bug fixes</li>
Daniel Veillardec78c0f2000-08-25 10:25:23 +0000[diff] [blame]976 <li>started adding routines to access xml parser context options</li>
Daniel Veillard786d7c82000-08-12 23:38:57 +0000[diff] [blame]977</ul>
978
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]979<h3>2.2.1: July 21 2000</h3>
Daniel Veillarda2679fa2000-07-22 02:38:15 +0000[diff] [blame]980<ul>
981 <li>a purely bug fixes release</li>
982 <li>fixed an encoding support problem when parsing from a memory block</li>
983 <li>fixed a DOCTYPE parsing problem</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]984 <li>removed a bug in the function allowing to override the memory
985 allocation routines</li>
Daniel Veillarda2679fa2000-07-22 02:38:15 +0000[diff] [blame]986</ul>
987
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]988<h3>2.2.0: July 14 2000</h3>
Daniel Veillard94e90602000-07-17 14:38:19 +0000[diff] [blame]989<ul>
990 <li>applied a lot of portability fixes</li>
991 <li>better encoding support/cleanup and saving (content is now always
992 encoded in UTF-8)</li>
993 <li>the HTML parser now correctly handles encodings</li>
994 <li>added xmlHasProp()</li>
995 <li>fixed a serious problem with &amp;#38;</li>
996 <li>propagated the fix to FTP client</li>
997 <li>cleanup, bugfixes, etc ...</li>
998 <li>Added a page about <a href="encoding.html">libxml Internationalization
999 support</a></li>
1000</ul>
1001
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1002<h3>1.8.9: July 9 2000</h3>
1003<ul>
1004 <li>fixed the spec the RPMs should be better</li>
1005 <li>fixed a serious bug in the FTP implementation, released 1.8.9 to solve
1006 rpmfind users problem</li>
1007</ul>
1008
Daniel Veillard6388e172000-07-03 16:07:19 +0000[diff] [blame]1009<h3>2.1.1: July 1 2000</h3>
1010<ul>
1011 <li>fixes a couple of bugs in the 2.1.0 packaging</li>
1012 <li>improvements on the HTML parser</li>
1013</ul>
1014
Daniel Veillard3f6f7f62000-06-30 17:58:25 +0000[diff] [blame]1015<h3>2.1.0 and 1.8.8: June 29 2000</h3>
1016<ul>
1017 <li>1.8.8 is mostly a comodity package for upgrading to libxml2 accoding to
1018 <a href="upgrade.html">new instructions</a>. It fixes a nasty problem
1019 about &amp;#38; charref parsing</li>
1020 <li>2.1.0 also ease the upgrade from libxml v1 to the recent version. it
1021 also contains numerous fixes and enhancements:
1022 <ul>
1023 <li>added xmlStopParser() to stop parsing</li>
1024 <li>improved a lot parsing speed when there is large CDATA blocs</li>
1025 <li>includes XPath patches provided by Picdar Technology</li>
1026 <li>tried to fix as much as possible DtD validation and namespace
1027 related problems</li>
1028 <li>output to a given encoding has been added/tested</li>
1029 <li>lot of various fixes</li>
1030 </ul>
1031 </li>
1032</ul>
1033
Daniel Veillarde0aed302000-04-16 08:52:20 +0000[diff] [blame]1034<h3>2.0.0: Apr 12 2000</h3>
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]1035<ul>
1036 <li>First public release of libxml2. If you are using libxml, it's a good
Daniel Veillarde0aed302000-04-16 08:52:20 +0000[diff] [blame]1037 idea to check the 1.x to 2.x upgrade instructions. NOTE: while initally
1038 scheduled for Apr 3 the relase occured only on Apr 12 due to massive
1039 workload.</li>
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]1040 <li>The include are now located under $prefix/include/libxml (instead of
Daniel Veillarde0aed302000-04-16 08:52:20 +0000[diff] [blame]1041 $prefix/include/gnome-xml), they also are referenced by
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1042 <pre>#include &lt;libxml/xxx.h&gt;</pre>
Daniel Veillarde0aed302000-04-16 08:52:20 +0000[diff] [blame]1043 <p>instead of</p>
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]1044 <pre>#include "xxx.h"</pre>
1045 </li>
Daniel Veillard8f621982000-03-20 13:07:15 +0000[diff] [blame]1046 <li>a new URI module for parsing URIs and following strictly RFC 2396</li>
1047 <li>the memory allocation routines used by libxml can now be overloaded
1048 dynamically by using xmlMemSetup()</li>
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]1049 <li>The previously CVS only tool tester has been renamed
1050 <strong>xmllint</strong> and is now installed as part of the libxml2
1051 package</li>
Daniel Veillarde0aed302000-04-16 08:52:20 +0000[diff] [blame]1052 <li>The I/O interface has been revamped. There is now ways to plug in
1053 specific I/O modules, either at the URI scheme detection level using
1054 xmlRegisterInputCallbacks() or by passing I/O functions when creating a
1055 parser context using xmlCreateIOParserCtxt()</li>
1056 <li>there is a C preprocessor macro LIBXML_VERSION providing the version
1057 number of the libxml module in use</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]1058 <li>a number of optional features of libxml can now be excluded at
1059 configure time (FTP/HTTP/HTML/XPath/Debug)</li>
Daniel Veillardedfb29b2000-03-14 19:59:05 +0000[diff] [blame]1060</ul>
1061
1062<h3>2.0.0beta: Mar 14 2000</h3>
1063<ul>
1064 <li>This is a first Beta release of libxml version 2</li>
Daniel Veillarde356c282001-03-10 12:32:04 +0000[diff] [blame]1065 <li>It's available only from<a href="ftp://xmlsoft.org/">xmlsoft.org
1066 FTP</a>, it's packaged as libxml2-2.0.0beta and available as tar and
1067 RPMs</li>
Daniel Veillardedfb29b2000-03-14 19:59:05 +0000[diff] [blame]1068 <li>This version is now the head in the Gnome CVS base, the old one is
1069 available under the tag LIB_XML_1_X</li>
1070 <li>This includes a very large set of changes. Froma programmatic point of
1071 view applications should not have to be modified too much, check the <a
1072 href="upgrade.html">upgrade page</a></li>
1073 <li>Some interfaces may changes (especially a bit about encoding).</li>
1074 <li>the updates includes:
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]1075 <ul>
Daniel Veillardedfb29b2000-03-14 19:59:05 +0000[diff] [blame]1076 <li>fix I18N support. ISO-Latin-x/UTF-8/UTF-16 (nearly) seems correctly
1077 handled now</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]1078 <li>Better handling of entities, especially well formedness checking
1079 and proper PEref extensions in external subsets</li>
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]1080 <li>DTD conditional sections</li>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1081 <li>Validation now correcly handle entities content</li>
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]1082 <li><a href="http://rpmfind.net/tools/gdome/messages/0039.html">change
1083 structures to accomodate DOM</a></li>
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]1084 </ul>
1085 </li>
Daniel Veillardedfb29b2000-03-14 19:59:05 +0000[diff] [blame]1086 <li>Serious progress were made toward compliance, <a
1087 href="conf/result.html">here are the result of the test</a> against the
1088 OASIS testsuite (except the japanese tests since I don't support that
1089 encoding yet). This URL is rebuilt every couple of hours using the CVS
1090 head version.</li>
Daniel Veillarde41f2b72000-01-30 20:00:07 +0000[diff] [blame]1091</ul>
1092
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1093<h3>1.8.7: Mar 6 2000</h3>
1094<ul>
1095 <li>This is a bug fix release:</li>
1096 <li>It is possible to disable the ignorable blanks heuristic used by
1097 libxml-1.x, a new function xmlKeepBlanksDefault(0) will allow this. Note
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]1098 that for adherence to XML spec, this behaviour will be disabled by
1099 default in 2.x . The same function will allow to keep compatibility for
1100 old code.</li>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1101 <li>Blanks in &lt;a&gt; &lt;/a&gt; constructs are not ignored anymore,
1102 avoiding heuristic is really the Right Way :-\</li>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1103 <li>The unchecked use of snprintf which was breaking libxml-1.8.6
1104 compilation on some platforms has been fixed</li>
1105 <li>nanoftp.c nanohttp.c: Fixed '#' and '?' stripping when processing
1106 URIs</li>
1107</ul>
1108
Daniel Veillarde41f2b72000-01-30 20:00:07 +0000[diff] [blame]1109<h3>1.8.6: Jan 31 2000</h3>
1110<ul>
1111 <li>added a nanoFTP transport module, debugged until the new version of <a
1112 href="http://rpmfind.net/linux/rpm2html/rpmfind.html">rpmfind</a> can use
1113 it without troubles</li>
Daniel Veillardda07c342000-01-25 18:31:22 +0000[diff] [blame]1114</ul>
1115
1116<h3>1.8.5: Jan 21 2000</h3>
1117<ul>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]1118 <li>adding APIs to parse a well balanced chunk of XML (production <a
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]1119 href="http://www.w3.org/TR/REC-xml#NT-content">[43] content</a> of the
1120 XML spec)</li>
Daniel Veillard461a66c2000-01-18 18:01:01 +0000[diff] [blame]1121 <li>fixed a hideous bug in xmlGetProp pointed by Rune.Djurhuus@fast.no</li>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1122 <li>Jody Goldberg &lt;jgoldberg@home.com&gt; provided another patch trying
1123 to solve the zlib checks problems</li>
Daniel Veillard461a66c2000-01-18 18:01:01 +0000[diff] [blame]1124 <li>The current state in gnome CVS base is expected to ship as 1.8.5 with
1125 gnumeric soon</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]1126</ul>
1127
1128<h3>1.8.4: Jan 13 2000</h3>
1129<ul>
1130 <li>bug fixes, reintroduced xmlNewGlobalNs(), fixed xmlNewNs()</li>
1131 <li>all exit() call should have been removed from libxml</li>
1132 <li>fixed a problem with INCLUDE_WINSOCK on WIN32 platform</li>
1133 <li>added newDocFragment()</li>
Daniel Veillardf84f71f2000-01-05 19:54:23 +0000[diff] [blame]1134</ul>
1135
1136<h3>1.8.3: Jan 5 2000</h3>
1137<ul>
1138 <li>a Push interface for the XML and HTML parsers</li>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1139 <li>a shell-like interface to the document tree (try tester --shell :-)</li>
Daniel Veillarddbfd6411999-12-28 16:35:14 +0000[diff] [blame]1140 <li>lots of bug fixes and improvement added over XMas hollidays</li>
Daniel Veillard437b87b2000-01-03 17:30:46 +0000[diff] [blame]1141 <li>fixed the DTD parsing code to work with the xhtml DTD</li>
Daniel Veillardf84f71f2000-01-05 19:54:23 +0000[diff] [blame]1142 <li>added xmlRemoveProp(), xmlRemoveID() and xmlRemoveRef()</li>
1143 <li>Fixed bugs in xmlNewNs()</li>
Daniel Veillard437b87b2000-01-03 17:30:46 +0000[diff] [blame]1144 <li>External entity loading code has been revamped, now it uses
Daniel Veillardf84f71f2000-01-05 19:54:23 +0000[diff] [blame]1145 xmlLoadExternalEntity(), some fix on entities processing were added</li>
Daniel Veillard437b87b2000-01-03 17:30:46 +0000[diff] [blame]1146 <li>cleaned up WIN32 includes of socket stuff</li>
Daniel Veillard5cb5ab81999-12-21 15:35:29 +0000[diff] [blame]1147</ul>
1148
1149<h3>1.8.2: Dec 21 1999</h3>
1150<ul>
Daniel Veillardb24054a1999-12-18 15:32:46 +0000[diff] [blame]1151 <li>I got another problem with includes and C++, I hope this issue is fixed
1152 for good this time</li>
Daniel Veillard5cb5ab81999-12-21 15:35:29 +0000[diff] [blame]1153 <li>Added a few tree modification functions: xmlReplaceNode,
1154 xmlAddPrevSibling, xmlAddNextSibling, xmlNodeSetName and
1155 xmlDocSetRootElement</li>
1156 <li>Tried to improve the HTML output with help from <a
1157 href="mailto:clahey@umich.edu">Chris Lahey</a></li>
Daniel Veillarde4e51311999-12-18 15:32:46 +0000[diff] [blame]1158</ul>
Daniel Veillardb24054a1999-12-18 15:32:46 +0000[diff] [blame]1159
Daniel Veillarde4e51311999-12-18 15:32:46 +0000[diff] [blame]1160<h3>1.8.1: Dec 18 1999</h3>
1161<ul>
1162 <li>various patches to avoid troubles when using libxml with C++ compilers
1163 the "namespace" keyword and C escaping in include files</li>
1164 <li>a problem in one of the core macros IS_CHAR was corrected</li>
1165 <li>fixed a bug introduced in 1.8.0 breaking default namespace processing,
1166 and more specifically the Dia application</li>
Daniel Veillard944b5ff1999-12-15 19:08:24 +0000[diff] [blame]1167 <li>fixed a posteriori validation (validation after parsing, or by using a
1168 Dtd not specified in the original document)</li>
Daniel Veillardb24054a1999-12-18 15:32:46 +0000[diff] [blame]1169 <li>fixed a bug in</li>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]1170</ul>
1171
1172<h3>1.8.0: Dec 12 1999</h3>
1173<ul>
1174 <li>cleanup, especially memory wise</li>
1175 <li>the parser should be more reliable, especially the HTML one, it should
1176 not crash, whatever the input !</li>
1177 <li>Integrated various patches, especially a speedup improvement for large
1178 dataset from <a href="mailto:cnygard@bellatlantic.net">Carl Nygard</a>,
1179 configure with --with-buffers to enable them.</li>
1180 <li>attribute normalization, oops should have been added long ago !</li>
1181 <li>attributes defaulted from Dtds should be available, xmlSetProp() now
1182 does entities escapting by default.</li>
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000[diff] [blame]1183</ul>
Daniel Veillard35008381999-10-25 13:15:52 +0000[diff] [blame]1184
1185<h3>1.7.4: Oct 25 1999</h3>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]1186<ul>
Daniel Veillard35008381999-10-25 13:15:52 +0000[diff] [blame]1187 <li>Lots of HTML improvement</li>
1188 <li>Fixed some errors when saving both XML and HTML</li>
1189 <li>More examples, the regression tests should now look clean</li>
1190 <li>Fixed a bug with contiguous charref</li>
1191</ul>
1192
1193<h3>1.7.3: Sep 29 1999</h3>
1194<ul>
1195 <li>portability problems fixed</li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]1196 <li>snprintf was used unconditionnally, leading to link problems on system
Daniel Veillard35008381999-10-25 13:15:52 +0000[diff] [blame]1197 were it's not available, fixed</li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]1198</ul>
1199
1200<h3>1.7.1: Sep 24 1999</h3>
1201<ul>
1202 <li>The basic type for strings manipulated by libxml has been renamed in
1203 1.7.1 from <strong>CHAR</strong> to <strong>xmlChar</strong>. The reason
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]1204 is that CHAR was conflicting with a predefined type on Windows. However
1205 on non WIN32 environment, compatibility is provided by the way of a
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]1206 <strong>#define </strong>.</li>
1207 <li>Changed another error : the use of a structure field called errno, and
1208 leading to troubles on platforms where it's a macro</li>
1209</ul>
1210
1211<h3>1.7.0: sep 23 1999</h3>
1212<ul>
1213 <li>Added the ability to fetch remote DTD or parsed entities, see the <a
Daniel Veillard9cb5ff42001-01-29 08:22:21 +0000[diff] [blame]1214 href="html/libxml-nanohttp.html">nanohttp</a> module.</li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]1215 <li>Added an errno to report errors by another mean than a simple printf
1216 like callback</li>
1217 <li>Finished ID/IDREF support and checking when validation</li>
1218 <li>Serious memory leaks fixed (there is now a <a
Daniel Veillard9cb5ff42001-01-29 08:22:21 +0000[diff] [blame]1219 href="html/libxml-xmlmemory.html">memory wrapper</a> module)</li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]1220 <li>Improvement of <a href="http://www.w3.org/TR/xpath">XPath</a>
1221 implementation</li>
1222 <li>Added an HTML parser front-end</li>
1223</ul>
1224
1225<h2><a name="XML">XML</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1226
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]1227<p><a href="http://www.w3.org/TR/REC-xml">XML is a standard</a> for
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1228markup-based structured documents. Here is <a name="example">an example XML
1229document</a>:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1230<pre>&lt;?xml version="1.0"?&gt;
1231&lt;EXAMPLE prop1="gnome is great" prop2="&amp;amp; linux too"&gt;
1232 &lt;head&gt;
1233 &lt;title&gt;Welcome to Gnome&lt;/title&gt;
1234 &lt;/head&gt;
1235 &lt;chapter&gt;
1236 &lt;title&gt;The Linux adventure&lt;/title&gt;
1237 &lt;p&gt;bla bla bla ...&lt;/p&gt;
1238 &lt;image href="linus.gif"/&gt;
1239 &lt;p&gt;...&lt;/p&gt;
1240 &lt;/chapter&gt;
1241&lt;/EXAMPLE&gt;</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1242
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]1243<p>The first line specifies that it's an XML document and gives useful
1244information about its encoding. Then the document is a text format whose
1245structure is specified by tags between brackets. <strong>Each tag opened has
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1246to be closed</strong>. XML is pedantic about this. However, if a tag is empty
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]1247(no content), a single tag can serve as both the opening and closing tag if
1248it ends with <code>/&gt;</code> rather than with <code>&gt;</code>. Note
1249that, for example, the image tag has no content (just an attribute) and is
1250closed by ending the tag with <code>/&gt;</code>.</p>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]1251
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]1252<p>XML can be applied sucessfully to a wide range of uses, from long term
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]1253structured document maintenance (where it follows the steps of SGML) to
1254simple data encoding mechanisms like configuration file formatting (glade),
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1255spreadsheets (gnumeric), or even shorter lived documents such as WebDAV where
1256it is used to encode remote calls between a client and a server.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1257
Daniel Veillard82687162001-01-22 15:32:01 +0000[diff] [blame]1258<h2><a name="XSLT">XSLT</a></h2>
1259
Daniel Veillard6e6a6cc2001-02-15 15:55:44 +0000[diff] [blame]1260<p>Check <a href="http://xmlsoft.org/XSLT">the separate libxslt page</a></p>
1261
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]1262<p><a href="http://www.w3.org/TR/xslt">XSL Transformations</a>, is a
1263language for transforming XML documents into other XML documents (or
1264HTML/textual output).</p>
Daniel Veillard82687162001-01-22 15:32:01 +0000[diff] [blame]1265
1266<p>A separate library called libxslt is being built on top of libxml2. This
1267module "libxslt" can be found in the Gnome CVS base too.</p>
1268
Daniel Veillard383b1472001-01-23 11:39:52 +0000[diff] [blame]1269<p>You can check the <a
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]1270href="http://cvs.gnome.org/lxr/source/libxslt/FEATURES">features</a>
1271supported and the progresses on the <a
Daniel Veillard82687162001-01-22 15:32:01 +0000[diff] [blame]1272href="http://cvs.gnome.org/lxr/source/libxslt/ChangeLog">Changelog</a></p>
1273
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]1274<h2><a name="architecture">libxml architecture</a></h2>
Daniel Veillard4540be42000-08-19 16:40:28 +0000[diff] [blame]1275
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]1276<p>Libxml is made of multiple components; some of them are optional, and most
1277of the block interfaces are public. The main components are:</p>
Daniel Veillard4540be42000-08-19 16:40:28 +0000[diff] [blame]1278<ul>
1279 <li>an Input/Output layer</li>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]1280 <li>FTP and HTTP client layers (optional)</li>
Daniel Veillard4540be42000-08-19 16:40:28 +0000[diff] [blame]1281 <li>an Internationalization layer managing the encodings support</li>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]1282 <li>a URI module</li>
Daniel Veillard4540be42000-08-19 16:40:28 +0000[diff] [blame]1283 <li>the XML parser and its basic SAX interface</li>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]1284 <li>an HTML parser using the same SAX interface (optional)</li>
Daniel Veillard4540be42000-08-19 16:40:28 +0000[diff] [blame]1285 <li>a SAX tree module to build an in-memory DOM representation</li>
1286 <li>a tree module to manipulate the DOM representation</li>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]1287 <li>a validation module using the DOM representation (optional)</li>
Daniel Veillard4540be42000-08-19 16:40:28 +0000[diff] [blame]1288 <li>an XPath module for global lookup in a DOM representation
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]1289 (optional)</li>
1290 <li>a debug module (optional)</li>
Daniel Veillard4540be42000-08-19 16:40:28 +0000[diff] [blame]1291</ul>
1292
1293<p>Graphically this gives the following:</p>
1294
1295<p><img src="libxml.gif" alt="a graphical view of the various"></p>
1296
1297<p></p>
1298
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]1299<h2><a name="tree">The tree output</a></h2>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1300
1301<p>The parser returns a tree built during the document analysis. The value
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]1302returned is an <strong>xmlDocPtr</strong> (i.e., a pointer to an
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1303<strong>xmlDoc</strong> structure). This structure contains information such
Daniel Veillard306be992000-07-03 12:38:45 +0000[diff] [blame]1304as the file name, the document type, and a <strong>children</strong> pointer
1305which is the root of the document (or more exactly the first child under the
1306root which is the document). The tree is made of <strong>xmlNode</strong>s,
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]1307chained in double-linked lists of siblings and with a children&lt;-&gt;parent
Daniel Veillard306be992000-07-03 12:38:45 +0000[diff] [blame]1308relationship. An xmlNode can also carry properties (a chain of xmlAttr
1309structures). An attribute may have a value which is a list of TEXT or
1310ENTITY_REF nodes.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1311
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1312<p>Here is an example (erroneous with respect to the XML spec since there
1313should be only one ELEMENT under the root):</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1314
1315<p><img src="structure.gif" alt=" structure.gif "></p>
1316
1317<p>In the source package there is a small program (not installed by default)
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]1318called <strong>xmllint</strong> which parses XML files given as argument and
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1319prints them back as parsed. This is useful for detecting errors both in XML
1320code and in the XML parser itself. It has an option <strong>--debug</strong>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]1321which prints the actual in-memory structure of the document; here is the
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1322result with the <a href="#example">example</a> given before:</p>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]1323<pre>DOCUMENT
1324version=1.0
1325standalone=true
1326 ELEMENT EXAMPLE
1327 ATTRIBUTE prop1
1328 TEXT
1329 content=gnome is great
1330 ATTRIBUTE prop2
1331 ENTITY_REF
1332 TEXT
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]1333 content= linux too
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]1334 ELEMENT head
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]1335 ELEMENT title
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]1336 TEXT
1337 content=Welcome to Gnome
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]1338 ELEMENT chapter
1339 ELEMENT title
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]1340 TEXT
1341 content=The Linux adventure
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]1342 ELEMENT p
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]1343 TEXT
1344 content=bla bla bla ...
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]1345 ELEMENT image
1346 ATTRIBUTE href
1347 TEXT
1348 content=linus.gif
1349 ELEMENT p
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]1350 TEXT
1351 content=...</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1352
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1353<p>This should be useful for learning the internal representation model.</p>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]1354
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]1355<h2><a name="interface">The SAX interface</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1356
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]1357<p>Sometimes the DOM tree output is just too large to fit reasonably into
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1358memory. In that case (and if you don't expect to save back the XML document
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]1359loaded using libxml), it's better to use the SAX interface of libxml. SAX is
1360a <strong>callback-based interface</strong> to the parser. Before parsing,
1361the application layer registers a customized set of callbacks which are
1362called by the library as it progresses through the XML input.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1363
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1364<p>To get more detailed step-by-step guidance on using the SAX interface of
Daniel Veillard4540be42000-08-19 16:40:28 +0000[diff] [blame]1365libxml, see the <a
1366href="http://www.daa.com.au/~james/gnome/xml-sax/xml-sax.html">nice
1367documentation</a>.written by <a href="mailto:james@daa.com.au">James
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1368Henstridge</a>.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1369
1370<p>You can debug the SAX behaviour by using the <strong>testSAX</strong>
1371program located in the gnome-xml module (it's usually not shipped in the
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1372binary packages of libxml, but you can find it in the tar source
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]1373distribution). Here is the sequence of callbacks that would be reported by
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1374testSAX when parsing the example XML document shown earlier:</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1375<pre>SAX.setDocumentLocator()
1376SAX.startDocument()
1377SAX.getEntity(amp)
1378SAX.startElement(EXAMPLE, prop1='gnome is great', prop2='&amp;amp; linux too')
1379SAX.characters( , 3)
1380SAX.startElement(head)
1381SAX.characters( , 4)
1382SAX.startElement(title)
1383SAX.characters(Welcome to Gnome, 16)
1384SAX.endElement(title)
1385SAX.characters( , 3)
1386SAX.endElement(head)
1387SAX.characters( , 3)
1388SAX.startElement(chapter)
1389SAX.characters( , 4)
1390SAX.startElement(title)
1391SAX.characters(The Linux adventure, 19)
1392SAX.endElement(title)
1393SAX.characters( , 4)
1394SAX.startElement(p)
1395SAX.characters(bla bla bla ..., 15)
1396SAX.endElement(p)
1397SAX.characters( , 4)
1398SAX.startElement(image, href='linus.gif')
1399SAX.endElement(image)
1400SAX.characters( , 4)
1401SAX.startElement(p)
1402SAX.characters(..., 3)
1403SAX.endElement(p)
1404SAX.characters( , 3)
1405SAX.endElement(chapter)
1406SAX.characters( , 1)
1407SAX.endElement(EXAMPLE)
1408SAX.endDocument()</pre>
1409
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]1410<p>Most of the other interfaces of libxml are based on the DOM tree-building
1411facility, so nearly everything up to the end of this document presupposes the
1412use of the standard DOM tree build. Note that the DOM tree itself is built by
1413a set of registered default callbacks, without internal specific
1414interface.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1415
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]1416<h2><a name="Validation">Validation &amp; DTDs</a></h2>
1417
1418<p>Table of Content:</p>
1419<ol>
1420 <li><a href="#General5">General overview</a></li>
1421 <li><a href="#definition">The definition</a></li>
1422 <li><a href="#Simple">Simple rules</a>
1423 <ol>
Daniel Veillard9c466822001-10-25 12:03:39 +0000[diff] [blame]1424 <li><a href="#reference">How to reference a DTD from a document</a></li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]1425 <li><a href="#Declaring">Declaring elements</a></li>
1426 <li><a href="#Declaring1">Declaring attributes</a></li>
1427 </ol>
1428 </li>
1429 <li><a href="#Some">Some examples</a></li>
1430 <li><a href="#validate">How to validate</a></li>
1431 <li><a href="#Other">Other resources</a></li>
1432</ol>
1433
1434<h3><a name="General5">General overview</a></h3>
1435
1436<p>Well what is validation and what is a DTD ?</p>
1437
1438<p>DTD is the acronym for Document Type Definition. This is a description of
1439the content for a familly of XML files. This is part of the XML 1.0
1440specification, and alows to describe and check that a given document instance
1441conforms to a set of rules detailing its structure and content.</p>
1442
1443<p>Validation is the process of checking a document against a DTD (more
1444generally against a set of construction rules).</p>
1445
1446<p>The validation process and building DTDs are the two most difficult parts
1447of the XML life cycle. Briefly a DTD defines all the possibles element to be
1448found within your document, what is the formal shape of your document tree
1449(by defining the allowed content of an element, either text, a regular
1450expression for the allowed list of children, or mixed content i.e. both text
1451and children). The DTD also defines the allowed attributes for all elements
1452and the types of the attributes.</p>
1453
1454<h3><a name="definition1">The definition</a></h3>
1455
1456<p>The <a href="http://www.w3.org/TR/REC-xml">W3C XML Recommendation</a> (<a
1457href="http://www.xml.com/axml/axml.html">Tim Bray's annotated version of
1458Rev1</a>):</p>
1459<ul>
1460 <li><a href="http://www.w3.org/TR/REC-xml#elemdecls">Declaring
1461 elements</a></li>
1462 <li><a href="http://www.w3.org/TR/REC-xml#attdecls">Declaring
1463 attributes</a></li>
1464</ul>
1465
1466<p>(unfortunately) all this is inherited from the SGML world, the syntax is
1467ancient...</p>
1468
1469<h3><a name="Simple1">Simple rules</a></h3>
1470
1471<p>Writing DTD can be done in multiple ways, the rules to build them if you
1472need something fixed or something which can evolve over time can be radically
1473different. Really complex DTD like Docbook ones are flexible but quite harder
1474to design. I will just focuse on DTDs for a formats with a fixed simple
1475structure. It is just a set of basic rules, and definitely not exhaustive nor
1476useable for complex DTD design.</p>
1477
1478<h4><a name="reference1">How to reference a DTD from a document</a>:</h4>
1479
1480<p>Assuming the top element of the document is <code>spec</code> and the dtd
1481is placed in the file <code>mydtd</code> in the subdirectory
1482<code>dtds</code> of the directory from where the document were loaded:</p>
1483
1484<p><code>&lt;!DOCTYPE spec SYSTEM "dtds/mydtd"&gt;</code></p>
1485
1486<p>Notes:</p>
1487<ul>
1488 <li>the system string is actually an URI-Reference (as defined in <a
1489 href="http://www.ietf.org/rfc/rfc2396.txt">RFC 2396</a>) so you can use a
1490 full URL string indicating the location of your DTD on the Web, this is a
1491 really good thing to do if you want others to validate your document</li>
1492 <li>it is also possible to associate a <code>PUBLIC</code> identifier (a
1493 magic string) so that the DTd is looked up in catalogs on the client side
1494 without having to locate it on the web</li>
1495 <li>a dtd contains a set of elements and attributes declarations, but they
1496 don't define what the root of the document should be. This is explicitely
1497 told to the parser/validator as the first element of the
1498 <code>DOCTYPE</code> declaration.</li>
1499</ul>
1500
1501<h4><a name="Declaring2">Declaring elements</a>:</h4>
1502
1503<p>The following declares an element <code>spec</code>:</p>
1504
1505<p><code>&lt;!ELEMENT spec (front, body, back?)&gt;</code></p>
1506
1507<p>it also expresses that the spec element contains one <code>front</code>,
1508one <code>body</code> and one optionnal <code>back</code> children elements
1509in this order. The declaration of one element of the structure and its
1510content are done in a single declaration. Similary the following declares
1511<code>div1</code> elements:</p>
1512
1513<p><code>&lt;!ELEMENT div1 (head, (p | list | note)*, div2*)&gt;</code></p>
1514
1515<p>means div1 contains one <code>head</code> then a series of optional
1516<code>p</code>, <code>list</code>s and <code>note</code>s and then an
1517optional <code>div2</code>. And last but not least an element can contain
1518text:</p>
1519
1520<p><code>&lt;!ELEMENT b (#PCDATA)&gt;</code></p>
1521
1522<p><code>b</code> contains text or being of mixed content (text and elements
1523in no particular order):</p>
1524
1525<p><code>&lt;!ELEMENT p (#PCDATA|a|ul|b|i|em)*&gt;</code></p>
1526
1527<p><code>p </code>can contain text or <code>a</code>, <code>ul</code>,
1528<code>b</code>, <code>i </code>or <code>em</code> elements in no particular
1529order.</p>
1530
1531<h4><a name="Declaring1">Declaring attributes</a>:</h4>
1532
1533<p>again the attributes declaration includes their content definition:</p>
1534
1535<p><code>&lt;!ATTLIST termdef name CDATA #IMPLIED&gt;</code></p>
1536
1537<p>means that the element <code>termdef</code> can have a <code>name</code>
1538attribute containing text (<code>CDATA</code>) and which is optionnal
1539(<code>#IMPLIED</code>). The attribute value can also be defined within a
1540set:</p>
1541
1542<p><code>&lt;!ATTLIST list type (bullets|ordered|glossary)
1543"ordered"&gt;</code></p>
1544
1545<p>means <code>list</code> element have a <code>type</code> attribute with 3
1546allowed values "bullets", "ordered" or "glossary" and which default to
1547"ordered" if the attribute is not explicitely specified.</p>
1548
1549<p>The content type of an attribute can be text (<code>CDATA</code>),
1550anchor/reference/references
1551(<code>ID</code>/<code>IDREF</code>/<code>IDREFS</code>), entity(ies)
1552(<code>ENTITY</code>/<code>ENTITIES</code>) or name(s)
1553(<code>NMTOKEN</code>/<code>NMTOKENS</code>). The following defines that a
1554<code>chapter</code> element can have an optional <code>id</code> attribute
1555of type <code>ID</code>, usable for reference from attribute of type
1556IDREF:</p>
1557
1558<p><code>&lt;!ATTLIST chapter id ID #IMPLIED&gt;</code></p>
1559
1560<p>The last value of an attribute definition can be <code>#REQUIRED
1561</code>meaning that the attribute has to be given, <code>#IMPLIED</code>
1562meaning that it is optional, or the default value (possibly prefixed by
1563<code>#FIXED</code> if it is the only allowed).</p>
1564
1565<p>Notes:</p>
1566<ul>
1567 <li>usually the attributes pertaining to a given element are declared in a
1568 single expression, but it is just a convention adopted by a lot of DTD
1569 writers:
1570 <pre>&lt;!ATTLIST termdef
1571 id ID #REQUIRED
1572 name CDATA #IMPLIED&gt;</pre>
1573 <p>The previous construct defines both <code>id</code> and
1574 <code>name</code> attributes for the element <code>termdef</code></p>
1575 </li>
1576</ul>
1577
1578<h3><a name="Some1">Some examples</a></h3>
1579
1580<p>The directory <code>test/valid/dtds/</code> in the libxml distribution
1581contains some complex DTD examples. The <code>test/valid/dia.xml</code>
1582example shows an XML file where the simple DTD is directly included within
1583the document.</p>
1584
1585<h3><a name="validate1">How to validate</a></h3>
1586
1587<p>The simplest is to use the xmllint program comming with libxml. The
1588<code>--valid</code> option turn on validation of the files given as input,
1589for example the following validates a copy of the first revision of the XML
15901.0 specification:</p>
1591
1592<p><code>xmllint --valid --noout test/valid/REC-xml-19980210.xml</code></p>
1593
1594<p>the -- noout is used to not output the resulting tree.</p>
1595
1596<p>The <code>--dtdvalid dtd</code> allows to validate the document(s) against
1597a given DTD.</p>
1598
1599<p>Libxml exports an API to handle DTDs and validation, check the <a
1600href="http://xmlsoft.org/html/libxml-valid.html">associated
1601description</a>.</p>
1602
1603<h3><a name="Other1">Other resources</a></h3>
1604
1605<p>DTDs are as old as SGML. So there may be a number of examples on-line, I
1606will just list one for now, others pointers welcome:</p>
1607<ul>
1608 <li><a href="http://www.xml101.com:8081/dtd/">XML-101 DTD</a></li>
1609</ul>
1610
1611<p>I suggest looking at the examples found under test/valid/dtd and any of
1612the large number of books available on XML. The dia example in test/valid
1613should be both simple and complete enough to allow you to build your own.</p>
1614
1615<p></p>
1616
1617<h2><a name="Memory">Memory Management</a></h2>
1618
1619<p>Table of Content:</p>
1620<ol>
1621 <li><a href="#General3">General overview</a></li>
Daniel Veillard9c466822001-10-25 12:03:39 +0000[diff] [blame]1622 <li><a href="#setting">Setting libxml set of memory routines</a></li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]1623 <li><a href="#cleanup">Cleaning up after parsing</a></li>
1624 <li><a href="#Debugging">Debugging routines</a></li>
1625 <li><a href="#General4">General memory requirements</a></li>
1626</ol>
1627
1628<h3><a name="General3">General overview</a></h3>
1629
1630<p>The module <code><a
1631href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlmemory.h</a></code>
1632provides the interfaces to the libxml memory system:</p>
1633<ul>
1634 <li>libxml does not use the libc memory allocator directly but xmlFree(),
1635 xmlMalloc() and xmlRealloc()</li>
1636 <li>those routines can be reallocated to a specific set of routine, by
1637 default the libc ones i.e. free(), malloc() and realloc()</li>
1638 <li>the xmlmemory.c module includes a set of debugging routine</li>
1639</ul>
1640
1641<h3><a name="setting">Setting libxml set of memory routines</a></h3>
1642
1643<p>It is sometimes useful to not use the default memory allocator, either for
1644debugging, analysis or to implement a specific behaviour on memory management
1645(like on embedded systems). Two function calls are available to do so:</p>
1646<ul>
1647 <li><a href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlMemGet ()</a>
1648 which return the current set of functions in use by the parser</li>
1649 <li><a
1650 href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlMemSetup()</a>
1651 which allow to set up a new set of memory allocation functions</li>
1652</ul>
1653
1654<p>Of course a call to xmlMemSetup() should probably be done before calling
1655any other libxml routines (unless you are sure your allocations routines are
1656compatibles).</p>
1657
1658<h3><a name="cleanup">Cleaning up after parsing</a></h3>
1659
1660<p>Libxml is not stateless, there is a few set of memory structures needing
1661allocation before the parser is fully functionnal (some encoding structures
1662for example). This also mean that once parsing is finished there is a tiny
1663amount of memory (a few hundred bytes) which can be recollected if you don't
1664reuse the parser immediately:</p>
1665<ul>
1666 <li><a href="http://xmlsoft.org/html/libxml-parser.html">xmlCleanupParser
1667 ()</a>
1668 is a centralized routine to free the parsing states. Note that it won't
1669 deallocate any produced tree if any (use the xmlFreeDoc() and related
1670 routines for this).</li>
1671 <li><a href="http://xmlsoft.org/html/libxml-parser.html">xmlInitParser
1672 ()</a>
1673 is the dual routine allowing to preallocate the parsing state which can
1674 be useful for example to avoid initialization reentrancy problems when
1675 using libxml in multithreaded applications</li>
1676</ul>
1677
1678<p>Generally xmlCleanupParser() is safe, if needed the state will be rebuild
1679at the next invocation of parser routines, but be careful of the consequences
1680in multithreaded applications.</p>
1681
1682<h3><a name="Debugging">Debugging routines</a></h3>
1683
1684<p>When configured using --with-mem-debug flag (off by default), libxml uses
1685a set of memory allocation debugging routineskeeping track of all allocated
1686blocks and the location in the code where the routine was called. A couple of
1687other debugging routines allow to dump the memory allocated infos to a file
1688or call a specific routine when a given block number is allocated:</p>
1689<ul>
1690 <li><a
1691 href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlMallocLoc()</a>
1692 <a
1693 href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlReallocLoc()</a>
1694 and <a
1695 href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlMemStrdupLoc()</a>
1696 are the memory debugging replacement allocation routines</li>
1697 <li><a href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlMemoryDump
1698 ()</a>
1699 dumps all the informations about the allocated memory block lefts in the
1700 <code>.memdump</code> file</li>
1701</ul>
1702
1703<p>When developping libxml memory debug is enabled, the tests programs call
1704xmlMemoryDump () and the "make test" regression tests will check for any
1705memory leak during the full regression test sequence, this helps a lot
1706ensuring that libxml does not leak memory and bullet proof memory
1707allocations use (some libc implementations are known to be far too permissive
1708resulting in major portability problems!).</p>
1709
1710<p>If the .memdump reports a leak, it displays the allocation function and
1711also tries to give some informations about the content and structure of the
1712allocated blocks left. This is sufficient in most cases to find the culprit,
1713but not always. Assuming the allocation problem is reproductible, it is
1714possible to find more easilly:</p>
1715<ol>
1716 <li>write down the block number xxxx not allocated</li>
1717 <li>export the environement variable XML_MEM_BREAKPOINT=xxxx</li>
1718 <li>run the program under a debugger and set a breakpoint on
1719 xmlMallocBreakpoint() a specific function called when this precise block
1720 is allocated</li>
1721 <li>when the breakpoint is reached you can then do a fine analysis of the
1722 allocation an step to see the condition resulting in the missing
1723 deallocation.</li>
1724</ol>
1725
1726<p>I used to use a commercial tool to debug libxml memory problems but after
1727noticing that it was not detecting memory leaks that simple mechanism was
1728used and proved extremely efficient until now.</p>
1729
1730<h3><a name="General4">General memory requirements</a></h3>
1731
1732<p>How much libxml memory require ? It's hard to tell in average it depends
1733of a number of things:</p>
1734<ul>
1735 <li>the parser itself should work in a fixed amout of memory, except for
1736 information maintained about the stacks of names and entities locations.
1737 The I/O and encoding handlers will probably account for a few KBytes.
1738 This is true for both the XML and HTML parser (though the HTML parser
1739 need more state).</li>
1740 <li>If you are generating the DOM tree then memory requirements will grow
1741 nearly lineary with the size of the data. In general for a balanced
1742 textual document the internal memory requirement is about 4 times the
1743 size of the UTF8 serialization of this document (exmple the XML-1.0
1744 recommendation is a bit more of 150KBytes and takes 650KBytes of main
1745 memory when parsed). Validation will add a amount of memory required for
1746 maintaining the external Dtd state which should be linear with the
1747 complexity of the content model defined by the Dtd</li>
1748 <li>If you don't care about the advanced features of libxml like
1749 validation, DOM, XPath or XPointer, but really need to work fixed memory
1750 requirements, then the SAX interface should be used.</li>
1751</ul>
1752
1753<p></p>
1754
1755<h2><a name="Encodings">Encodings support</a></h2>
1756
1757<p>Table of Content:</p>
1758<ol>
1759 <li><a href="encoding.html#What">What does internationalization support
1760 mean ?</a></li>
1761 <li><a href="encoding.html#internal">The internal encoding, how and
1762 why</a></li>
1763 <li><a href="encoding.html#implemente">How is it implemented ?</a></li>
1764 <li><a href="encoding.html#Default">Default supported encodings</a></li>
1765 <li><a href="encoding.html#extend">How to extend the existing
1766 support</a></li>
1767</ol>
1768
1769<h3><a name="What">What does internationalization support mean ?</a></h3>
1770
1771<p>XML was designed from the start to allow the support of any character set
1772by using Unicode. Any conformant XML parser has to support the UTF-8 and
1773UTF-16 default encodings which can both express the full unicode ranges. UTF8
1774is a variable length encoding whose greatest point are to resuse the same
1775emcoding for ASCII and to save space for Western encodings, but it is a bit
1776more complex to handle in practice. UTF-16 use 2 bytes per characters (and
1777sometimes combines two pairs), it makes implementation easier, but looks a
1778bit overkill for Western languages encoding. Moreover the XML specification
1779allows document to be encoded in other encodings at the condition that they
1780are clearly labelled as such. For example the following is a wellformed XML
1781document encoded in ISO-8859 1 and using accentuated letter that we French
1782likes for both markup and content:</p>
1783<pre>&lt;?xml version="1.0" encoding="ISO-8859-1"?&gt;
1784&lt;très&gt;là&lt;/très&gt;</pre>
1785
1786<p>Having internationalization support in libxml means the foolowing:</p>
1787<ul>
1788 <li>the document is properly parsed</li>
1789 <li>informations about it's encoding are saved</li>
1790 <li>it can be modified</li>
1791 <li>it can be saved in its original encoding</li>
1792 <li>it can also be saved in another encoding supported by libxml (for
1793 example straight UTF8 or even an ASCII form)</li>
1794</ul>
1795
1796<p>Another very important point is that the whole libxml API, with the
1797exception of a few routines to read with a specific encoding or save to a
1798specific encoding, is completely agnostic about the original encoding of the
1799document.</p>
1800
1801<p>It should be noted too that the HTML parser embedded in libxml now obbey
1802the same rules too, the following document will be (as of 2.2.2) handled in
1803an internationalized fashion by libxml too:</p>
1804<pre>&lt;!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"
1805 "http://www.w3.org/TR/REC-html40/loose.dtd"&gt;
1806&lt;html lang="fr"&gt;
1807&lt;head&gt;
1808 &lt;META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=ISO-8859-1"&gt;
1809&lt;/head&gt;
1810&lt;body&gt;
1811&lt;p&gt;W3C crée des standards pour le Web.&lt;/body&gt;
1812&lt;/html&gt;</pre>
1813
1814<h3><a name="internal">The internal encoding, how and why</a></h3>
1815
1816<p>One of the core decision was to force all documents to be converted to a
1817default internal encoding, and that encoding to be UTF-8, here are the
1818rationale for those choices:</p>
1819<ul>
1820 <li>keeping the native encoding in the internal form would force the libxml
1821 users (or the code associated) to be fully aware of the encoding of the
1822 original document, for examples when adding a text node to a document,
1823 the content would have to be provided in the document encoding, i.e. the
1824 client code would have to check it before hand, make sure it's conformant
1825 to the encoding, etc ... Very hard in practice, though in some specific
1826 cases this may make sense.</li>
1827 <li>the second decision was which encoding. From the XML spec only UTF8 and
1828 UTF16 really makes sense as being the two only encodings for which there
1829 is amndatory support. UCS-4 (32 bits fixed size encoding) could be
1830 considered an intelligent choice too since it's a direct Unicode mapping
1831 support. I selected UTF-8 on the basis of efficiency and compatibility
1832 with surrounding software:
1833 <ul>
1834 <li>UTF-8 while a bit more complex to convert from/to (i.e. slightly
1835 more costly to import and export CPU wise) is also far more compact
1836 than UTF-16 (and UCS-4) for a majority of the documents I see it used
1837 for right now (RPM RDF catalogs, advogato data, various configuration
1838 file formats, etc.) and the key point for today's computer
1839 architecture is efficient uses of caches. If one nearly double the
1840 memory requirement to store the same amount of data, this will trash
1841 caches (main memory/external caches/internal caches) and my take is
1842 that this harms the system far more than the CPU requirements needed
1843 for the conversion to UTF-8</li>
1844 <li>Most of libxml version 1 users were using it with straight ASCII
1845 most of the time, doing the conversion with an internal encoding
1846 requiring all their code to be rewritten was a serious show-stopper
1847 for using UTF-16 or UCS-4.</li>
1848 <li>UTF-8 is being used as the de-facto internal encoding standard for
1849 related code like the <a href="http://www.pango.org/">pango</a>
1850 upcoming Gnome text widget, and a lot of Unix code (yep another place
1851 where Unix programmer base takes a different approach from Microsoft
1852 - they are using UTF-16)</li>
1853 </ul>
1854 </li>
1855</ul>
1856
1857<p>What does this mean in practice for the libxml user:</p>
1858<ul>
1859 <li>xmlChar, the libxml data type is a byte, those bytes must be assembled
1860 as UTF-8 valid strings. The proper way to terminate an xmlChar * string
1861 is simply to append 0 byte, as usual.</li>
1862 <li>One just need to make sure that when using chars outside the ASCII set,
1863 the values has been properly converted to UTF-8</li>
1864</ul>
1865
1866<h3><a name="implemente">How is it implemented ?</a></h3>
1867
1868<p>Let's describe how all this works within libxml, basically the I18N
1869(internationalization) support get triggered only during I/O operation, i.e.
1870when reading a document or saving one. Let's look first at the reading
1871sequence:</p>
1872<ol>
1873 <li>when a document is processed, we usually don't know the encoding, a
1874 simple heuristic allows to detect UTF-18 and UCS-4 from whose where the
1875 ASCII range (0-0x7F) maps with ASCII</li>
1876 <li>the xml declaration if available is parsed, including the encoding
1877 declaration. At that point, if the autodetected encoding is different
1878 from the one declared a call to xmlSwitchEncoding() is issued.</li>
1879 <li>If there is no encoding declaration, then the input has to be in either
1880 UTF-8 or UTF-16, if it is not then at some point when processing the
1881 input, the converter/checker of UTF-8 form will raise an encoding error.
1882 You may end-up with a garbled document, or no document at all ! Example:
1883 <pre>~/XML -&gt; ./xmllint err.xml
1884err.xml:1: error: Input is not proper UTF-8, indicate encoding !
1885&lt;très&gt;là&lt;/très&gt;
1886 ^
1887err.xml:1: error: Bytes: 0xE8 0x73 0x3E 0x6C
1888&lt;très&gt;là&lt;/très&gt;
1889 ^</pre>
1890 </li>
1891 <li>xmlSwitchEncoding() does an encoding name lookup, canonalize it, and
1892 then search the default registered encoding converters for that encoding.
1893 If it's not within the default set and iconv() support has been compiled
1894 it, it will ask iconv for such an encoder. If this fails then the parser
1895 will report an error and stops processing:
1896 <pre>~/XML -&gt; ./xmllint err2.xml
1897err2.xml:1: error: Unsupported encoding UnsupportedEnc
1898&lt;?xml version="1.0" encoding="UnsupportedEnc"?&gt;
1899 ^</pre>
1900 </li>
1901 <li>From that point the encoder process progressingly the input (it is
1902 plugged as a front-end to the I/O module) for that entity. It captures
1903 and convert on-the-fly the document to be parsed to UTF-8. The parser
1904 itself just does UTF-8 checking of this input and process it
1905 transparently. The only difference is that the encoding information has
1906 been added to the parsing context (more precisely to the input
1907 corresponding to this entity).</li>
1908 <li>The result (when using DOM) is an internal form completely in UTF-8
1909 with just an encoding information on the document node.</li>
1910</ol>
1911
1912<p>Ok then what's happen when saving the document (assuming you
1913colllected/built an xmlDoc DOM like structure) ? It depends on the function
1914called, xmlSaveFile() will just try to save in the original encoding, while
1915xmlSaveFileTo() and xmlSaveFileEnc() can optionally save to a given
1916encoding:</p>
1917<ol>
1918 <li>if no encoding is given, libxml will look for an encoding value
1919 associated to the document and if it exists will try to save to that
1920 encoding,
1921 <p>otherwise everything is written in the internal form, i.e. UTF-8</p>
1922 </li>
1923 <li>so if an encoding was specified, either at the API level or on the
1924 document, libxml will again canonalize the encoding name, lookup for a
1925 converter in the registered set or through iconv. If not found the
1926 function will return an error code</li>
1927 <li>the converter is placed before the I/O buffer layer, as another kind of
1928 buffer, then libxml will simply push the UTF-8 serialization to through
1929 that buffer, which will then progressively be converted and pushed onto
1930 the I/O layer.</li>
1931 <li>It is possible that the converter code fails on some input, for example
1932 trying to push an UTF-8 encoded chinese character through the UTF-8 to
1933 ISO-8859-1 converter won't work. Since the encoders are progressive they
1934 will just report the error and the number of bytes converted, at that
1935 point libxml will decode the offending character, remove it from the
1936 buffer and replace it with the associated charRef encoding &amp;#123; and
1937 resume the convertion. This guarante that any document will be saved
1938 without losses (except for markup names where this is not legal, this is
1939 a problem in the current version, in pactice avoid using non-ascci
1940 characters for tags or attributes names @@). A special "ascii" encoding
1941 name is used to save documents to a pure ascii form can be used when
1942 portability is really crucial</li>
1943</ol>
1944
1945<p>Here is a few examples based on the same test document:</p>
1946<pre>~/XML -&gt; ./xmllint isolat1
1947&lt;?xml version="1.0" encoding="ISO-8859-1"?&gt;
1948&lt;très&gt;là&lt;/très&gt;
1949~/XML -&gt; ./xmllint --encode UTF-8 isolat1
1950&lt;?xml version="1.0" encoding="UTF-8"?&gt;
1951&lt;très&gt;là  &lt;/très&gt;
1952~/XML -&gt; </pre>
1953
1954<p>The same processing is applied (and reuse most of the code) for HTML I18N
1955processing. Looking up and modifying the content encoding is a bit more
1956difficult since it is located in a &lt;meta&gt; tag under the &lt;head&gt;,
1957so a couple of functions htmlGetMetaEncoding() and htmlSetMetaEncoding() have
1958been provided. The parser also attempts to switch encoding on the fly when
1959detecting such a tag on input. Except for that the processing is the same
1960(and again reuses the same code).</p>
1961
1962<h3><a name="Default">Default supported encodings</a></h3>
1963
1964<p>libxml has a set of default converters for the following encodings
1965(located in encoding.c):</p>
1966<ol>
1967 <li>UTF-8 is supported by default (null handlers)</li>
1968 <li>UTF-16, both little and big endian</li>
1969 <li>ISO-Latin-1 (ISO-8859-1) covering most western languages</li>
1970 <li>ASCII, useful mostly for saving</li>
1971 <li>HTML, a specific handler for the conversion of UTF-8 to ASCII with HTML
1972 predefined entities like &amp;copy; for the Copyright sign.</li>
1973</ol>
1974
1975<p>More over when compiled on an Unix platfor with iconv support the full set
1976of encodings supported by iconv can be instantly be used by libxml. On a
1977linux machine with glibc-2.1 the list of supported encodings and aliases fill
19783 full pages, and include UCS-4, the full set of ISO-Latin encodings, and the
1979various Japanese ones.</p>
1980
1981<h4>Encoding aliases</h4>
1982
1983<p>From 2.2.3, libxml has support to register encoding names aliases. The
1984goal is to be able to parse document whose encoding is supported but where
1985the name differs (for example from the default set of names accepted by
1986iconv). The following functions allow to register and handle new aliases for
1987existing encodings. Once registered libxml will automatically lookup the
1988aliases when handling a document:</p>
1989<ul>
1990 <li>int xmlAddEncodingAlias(const char *name, const char *alias);</li>
1991 <li>int xmlDelEncodingAlias(const char *alias);</li>
1992 <li>const char * xmlGetEncodingAlias(const char *alias);</li>
1993 <li>void xmlCleanupEncodingAliases(void);</li>
1994</ul>
1995
1996<h3><a name="extend">How to extend the existing support</a></h3>
1997
1998<p>Well adding support for new encoding, or overriding one of the encoders
1999(assuming it is buggy) should not be hard, just write an input and output
2000conversion routines to/from UTF-8, and register them using
2001xmlNewCharEncodingHandler(name, xxxToUTF8, UTF8Toxxx), and they will be
2002called automatically if the parser(s) encounter such an encoding name
2003(register it uppercase, this will help). The description of the encoders,
2004their arguments and expected return values are described in the encoding.h
2005header.</p>
2006
2007<p>A quick note on the topic of subverting the parser to use a different
2008internal encoding than UTF-8, in some case people will absolutely want to
2009keep the internal encoding different, I think it's still possible (but the
2010encoding must be compliant with ASCII on the same subrange) though I didn't
2011tried it. The key is to override the default conversion routines (by
2012registering null encoders/decoders for your charsets), and bypass the UTF-8
2013checking of the parser by setting the parser context charset
2014(ctxt-&gt;charset) to something different than XML_CHAR_ENCODING_UTF8, but
2015there is no guarantee taht this will work. You may also have some troubles
2016saving back.</p>
2017
2018<p>Basically proper I18N support is important, this requires at least
2019libxml-2.0.0, but a lot of features and corrections are really available only
2020starting 2.2.</p>
2021
2022<h2><a name="IO">I/O Interfaces</a></h2>
2023
2024<p>Table of Content:</p>
2025<ol>
2026 <li><a href="#General1">General overview</a></li>
2027 <li><a href="#basic">The basic buffer type</a></li>
2028 <li><a href="#Input">Input I/O handlers</a></li>
2029 <li><a href="#Output">Output I/O handlers</a></li>
2030 <li><a href="#entities">The entities loader</a></li>
2031 <li><a href="#Example2">Example of customized I/O</a></li>
2032</ol>
2033
2034<h3><a name="General1">General overview</a></h3>
2035
2036<p>The module <code><a
2037href="http://xmlsoft.org/html/libxml-xmlio.html">xmlIO.h</a></code> provides
2038the interfaces to the libxml I/O system. This consists of 4 main parts:</p>
2039<ul>
2040 <li>Entities loader, this is a routine which tries to fetch the entities
2041 (files) based on their PUBLIC and SYSTEM identifiers. The default loader
2042 don't look at the public identifier since libxml do not maintain a
2043 catalog. You can redefine you own entity loader by using
2044 <code>xmlGetExternalEntityLoader()</code> and
Daniel Veillard9c466822001-10-25 12:03:39 +0000[diff] [blame]2045 <code>xmlSetExternalEntityLoader()</code>. <a href="#entities">Check the
2046 example</a>.</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2047 <li>Input I/O buffers which are a commodity structure used by the parser(s)
2048 input layer to handle fetching the informations to feed the parser. This
2049 provides buffering and is also a placeholder where the encoding
2050 convertors to UTF8 are piggy-backed.</li>
2051 <li>Output I/O buffers are similar to the Input ones and fulfill similar
2052 task but when generating a serialization from a tree.</li>
2053 <li>A mechanism to register sets of I/O callbacks and associate them with
2054 specific naming schemes like the protocol part of the URIs.
2055 <p>This affect the default I/O operations and allows to use specific I/O
2056 handlers for certain names.</p>
2057 </li>
2058</ul>
2059
2060<p>The general mechanism used when loading http://rpmfind.net/xml.html for
2061example in the HTML parser is the following:</p>
2062<ol>
2063 <li>The default entity loader calls <code>xmlNewInputFromFile()</code> with
2064 the parsing context and the URI string.</li>
2065 <li>the URI string is checked against the existing registered handlers
2066 using their match() callback function, if the HTTP module was compiled
2067 in, it is registered and its match() function will succeeds</li>
2068 <li>the open() function of the handler is called and if successful will
2069 return an I/O Input buffer</li>
2070 <li>the parser will the start reading from this buffer and progressively
2071 fetch information from the resource, calling the read() function of the
2072 handler until the resource is exhausted</li>
2073 <li>if an encoding change is detected it will be installed on the input
2074 buffer, providing buffering and efficient use of the conversion
2075 routines</li>
2076 <li>once the parser has finished, the close() function of the handler is
2077 called once and the Input buffer and associed resources are
2078 deallocated.</li>
2079</ol>
2080
2081<p>The user defined callbacks are checked first to allow overriding of the
2082default libxml I/O routines.</p>
2083
2084<h3><a name="basic">The basic buffer type</a></h3>
2085
2086<p>All the buffer manipulation handling is done using the
2087<code>xmlBuffer</code> type define in <code><a
2088href="http://xmlsoft.org/html/libxml-tree.html">tree.h</a> </code>which is a
2089resizable memory buffer. The buffer allocation strategy can be selected to be
2090either best-fit or use an exponential doubling one (CPU vs. memory use
2091tradeoff). The values are <code>XML_BUFFER_ALLOC_EXACT</code> and
2092<code>XML_BUFFER_ALLOC_DOUBLEIT</code>, and can be set individually or on a
2093system wide basis using <code>xmlBufferSetAllocationScheme()</code>. A number
2094of functions allows to manipulate buffers with names starting with the
2095<code>xmlBuffer...</code> prefix.</p>
2096
2097<h3><a name="Input">Input I/O handlers</a></h3>
2098
2099<p>An Input I/O handler is a simple structure
2100<code>xmlParserInputBuffer</code> containing a context associated to the
2101resource (file descriptor, or pointer to a protocol handler), the read() and
2102close() callbacks to use and an xmlBuffer. And extra xmlBuffer and a charset
2103encoding handler are also present to support charset conversion when
2104needed.</p>
2105
2106<h3><a name="Output">Output I/O handlers</a></h3>
2107
2108<p>An Output handler <code>xmlOutputBuffer</code> is completely similar to an
2109Input one except the callbacks are write() and close().</p>
2110
2111<h3><a name="entities">The entities loader</a></h3>
2112
2113<p>The entity loader resolves requests for new entities and create inputs for
2114the parser. Creating an input from a filename or an URI string is done
2115through the xmlNewInputFromFile() routine. The default entity loader do not
2116handle the PUBLIC identifier associated with an entity (if any). So it just
2117calls xmlNewInputFromFile() with the SYSTEM identifier (which is mandatory in
2118XML).</p>
2119
2120<p>If you want to hook up a catalog mechanism then you simply need to
2121override the default entity loader, here is an example:</p>
2122<pre>#include &lt;libxml/xmlIO.h&gt;
2123
2124xmlExternalEntityLoader defaultLoader = NULL;
2125
2126xmlParserInputPtr
2127xmlMyExternalEntityLoader(const char *URL, const char *ID,
2128 xmlParserCtxtPtr ctxt) {
2129 xmlParserInputPtr ret;
2130 const char *fileID = NULL;
2131 /* lookup for the fileID depending on ID */
2132
2133 ret = xmlNewInputFromFile(ctxt, fileID);
2134 if (ret != NULL)
2135 return(ret);
2136 if (defaultLoader != NULL)
2137 ret = defaultLoader(URL, ID, ctxt);
2138 return(ret);
2139}
2140
2141int main(..) {
2142 ...
2143
2144 /*
2145 * Install our own entity loader
2146 */
2147 defaultLoader = xmlGetExternalEntityLoader();
2148 xmlSetExternalEntityLoader(xmlMyExternalEntityLoader);
2149
2150 ...
2151}</pre>
2152
2153<h3><a name="Example2">Example of customized I/O</a></h3>
2154
2155<p>This example come from <a href="http://xmlsoft.org/messages/0708.html">a
2156real use case</a>, xmlDocDump() closes the FILE * passed by the application
2157and this was a problem. The <a
2158href="http://xmlsoft.org/messages/0711.html">solution</a> was to redefine a
2159new output handler with the closing call deactivated:</p>
2160<ol>
2161 <li>First define a new I/O ouput allocator where the output don't close the
2162 file:
2163 <pre>xmlOutputBufferPtr
2164xmlOutputBufferCreateOwn(FILE *file, xmlCharEncodingHandlerPtr encoder) {
2165    xmlOutputBufferPtr ret;
2166    
2167    if (xmlOutputCallbackInitialized == 0)
2168        xmlRegisterDefaultOutputCallbacks();
2169
2170    if (file == NULL) return(NULL);
2171    ret = xmlAllocOutputBuffer(encoder);
2172    if (ret != NULL) {
2173        ret-&gt;context = file;
2174        ret-&gt;writecallback = xmlFileWrite;
2175        ret-&gt;closecallback = NULL; /* No close callback */
2176    }
2177    return(ret); <br>
2178
2179
2180
Daniel Veillard9c466822001-10-25 12:03:39 +0000[diff] [blame]2181
2182
Daniel Veillardc6271d22001-10-27 07:50:58 +0000[diff] [blame]2183
Daniel Veillard51095312001-10-28 18:51:57 +0000[diff] [blame]2184
Daniel Veillard52dcab32001-10-30 12:51:17 +0000[diff] [blame]2185
Daniel Veillarded421aa2001-11-04 21:22:45 +0000[diff] [blame]2186
Daniel Veillard43d3f612001-11-10 11:57:23 +0000[diff] [blame]2187
Daniel Veillarda4871052001-11-26 13:19:48 +0000[diff] [blame]2188
Daniel Veillard1aadc442001-11-28 13:10:32 +0000[diff] [blame]2189
Daniel Veillardef90ba72001-12-07 14:24:22 +0000[diff] [blame^]2190
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2191} </pre>
2192 </li>
2193 <li>And then use it to save the document:
2194 <pre>FILE *f;
2195xmlOutputBufferPtr output;
2196xmlDocPtr doc;
2197int res;
2198
2199f = ...
2200doc = ....
2201
2202output = xmlOutputBufferCreateOwn(f, NULL);
2203res = xmlSaveFileTo(output, doc, NULL);
2204 </pre>
2205 </li>
2206</ol>
2207
2208<h2><a name="Catalog">Catalog support</a></h2>
2209
2210<p>Table of Content:</p>
2211<ol>
2212 <li><a href="General2">General overview</a></li>
2213 <li><a href="#definition">The definition</a></li>
2214 <li><a href="#Simple">Using catalogs</a></li>
2215 <li><a href="#Some">Some examples</a></li>
2216 <li><a href="#reference">How to tune catalog usage</a></li>
2217 <li><a href="#validate">How to debug catalog processing</a></li>
2218 <li><a href="#Declaring">How to create and maintain catalogs</a></li>
2219 <li><a href="#implemento">The implementor corner quick review of the
2220 API</a></li>
2221 <li><a href="#Other">Other resources</a></li>
2222</ol>
2223
2224<h3><a name="General2">General overview</a></h3>
2225
2226<p>What is a catalog? Basically it's a lookup mechanism used when an entity
2227(a file or a remote resource) references another entity. The catalog lookup
2228is inserted between the moment the reference is recognized by the software
2229(XML parser, stylesheet processing, or even images referenced for inclusion
2230in a rendering) and the time where loading that resource is actually
2231started.</p>
2232
2233<p>It is basically used for 3 things:</p>
2234<ul>
2235 <li>mapping from "logical" names, the public identifiers and a more
2236 concrete name usable for download (and URI). For example it can associate
2237 the logical name
2238 <p>"-//OASIS//DTD DocBook XML V4.1.2//EN"</p>
2239 <p>of the DocBook 4.1.2 XML DTD with the actual URL where it can be
2240 downloaded</p>
2241 <p>http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd</p>
2242 </li>
2243 <li>remapping from a given URL to another one, like an HTTP indirection
2244 saying that
2245 <p>"http://www.oasis-open.org/committes/tr.xsl"</p>
2246 <p>should really be looked at</p>
2247 <p>"http://www.oasis-open.org/committes/entity/stylesheets/base/tr.xsl"</p>
2248 </li>
2249 <li>providing a local cache mechanism allowing to load the entities
2250 associated to public identifiers or remote resources, this is a really
2251 important feature for any significant deployment of XML or SGML since it
2252 allows to avoid the aleas and delays associated to fetching remote
2253 resources.</li>
2254</ul>
2255
2256<h3><a name="definition">The definitions</a></h3>
2257
2258<p>Libxml, as of 2.4.3 implements 2 kind of catalogs:</p>
2259<ul>
2260 <li>the older SGML catalogs, the official spec is SGML Open Technical
2261 Resolution TR9401:1997, but is better understood by reading <a
2262 href="http://www.jclark.com/sp/catalog.htm">the SP Catalog page</a> from
2263 James Clark. This is relatively old and not the preferred mode of
2264 operation of libxml.</li>
2265 <li><a href="http://www.oasis-open.org/committees/entity/spec.html">XML
2266 Catalogs</a>
2267 is far more flexible, more recent, uses an XML syntax and should scale
2268 quite better. This is the default option of libxml.</li>
2269</ul>
2270
2271<p></p>
2272
2273<h3><a name="Simple">Using catalog</a></h3>
2274
2275<p>In a normal environment libxml will by default check the presence of a
2276catalog in /etc/xml/catalog, and assuming it has been correctly populated,
2277the processing is completely transparent to the document user. To take a
2278concrete example, suppose you are authoring a DocBook document, this one
2279starts with the following DOCTYPE definition:</p>
2280<pre>&lt;?xml version='1.0'?&gt;
2281&lt;!DOCTYPE book PUBLIC "-//Norman Walsh//DTD DocBk XML V3.1.4//EN"
2282 "http://nwalsh.com/docbook/xml/3.1.4/db3xml.dtd"&gt;</pre>
2283
2284<p>When validating the document with libxml, the catalog will be
2285automatically consulted to lookup the public identifier "-//Norman Walsh//DTD
2286DocBk XML V3.1.4//EN" and the system identifier
2287"http://nwalsh.com/docbook/xml/3.1.4/db3xml.dtd", and if these entities have
2288been installed on your system and the catalogs actually point to them, libxml
2289will fetch them from the local disk.</p>
2290
2291<p style="font-size: 10pt"><strong>Note</strong>: Really don't use this
2292DOCTYPE example it's a really old version, but is fine as an example.</p>
2293
2294<p>Libxml will check the catalog each time that it is requested to load an
2295entity, this includes DTD, external parsed entities, stylesheets, etc ... If
2296your system is correctly configured all the authoring phase and processing
2297should use only local files, even if your document stays portable because it
2298uses the canonical public and system ID, referencing the remote document.</p>
2299
2300<h3><a name="Some">Some examples:</a></h3>
2301
2302<p>Here is a couple of fragments from XML Catalogs used in libxml early
2303regression tests in <code>test/catalogs</code> :</p>
2304<pre>&lt;?xml version="1.0"?&gt;
2305&lt;!DOCTYPE catalog PUBLIC
2306 "-//OASIS//DTD Entity Resolution XML Catalog V1.0//EN"
2307 "http://www.oasis-open.org/committees/entity/release/1.0/catalog.dtd"&gt;
2308&lt;catalog xmlns="urn:oasis:names:tc:entity:xmlns:xml:catalog"&gt;
2309 &lt;public publicId="-//OASIS//DTD DocBook XML V4.1.2//EN"
2310 uri="http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd"/&gt;
2311...</pre>
2312
2313<p>This is the beginning of a catalog for DocBook 4.1.2, XML Catalogs are
2314written in XML, there is a specific namespace for catalog elements
2315"urn:oasis:names:tc:entity:xmlns:xml:catalog". The first entry in this
2316catalog is a <code>public</code> mapping it allows to associate a Public
2317Identifier with an URI.</p>
2318<pre>...
2319 &lt;rewriteSystem systemIdStartString="http://www.oasis-open.org/docbook/"
2320 rewritePrefix="file:///usr/share/xml/docbook/"/&gt;
2321...</pre>
2322
2323<p>A <code>rewriteSystem</code> is a very powerful instruction, it says that
2324any URI starting with a given prefix should be looked at another URI
2325constructed by replacing the prefix with an new one. In effect this acts like
2326a cache system for a full area of the Web. In practice it is extremely useful
2327with a file prefix if you have installed a copy of those resources on your
2328local system.</p>
2329<pre>...
2330&lt;delegatePublic publicIdStartString="-//OASIS//DTD XML Catalog //"
2331 catalog="file:///usr/share/xml/docbook.xml"/&gt;
2332&lt;delegatePublic publicIdStartString="-//OASIS//ENTITIES DocBook XML"
2333 catalog="file:///usr/share/xml/docbook.xml"/&gt;
2334&lt;delegatePublic publicIdStartString="-//OASIS//DTD DocBook XML"
2335 catalog="file:///usr/share/xml/docbook.xml"/&gt;
2336&lt;delegateSystem systemIdStartString="http://www.oasis-open.org/docbook/"
2337 catalog="file:///usr/share/xml/docbook.xml"/&gt;
2338&lt;delegateURI uriStartString="http://www.oasis-open.org/docbook/"
2339 catalog="file:///usr/share/xml/docbook.xml"/&gt;
2340...</pre>
2341
2342<p>Delegation is the core features which allows to build a tree of catalogs,
2343easier to maintain than a single catalog, based on Public Identifier, System
2344Identifier or URI prefixes it instructs the catalog software to look up
2345entries in another resource. This feature allow to build hierarchies of
2346catalogs, the set of entries presented should be sufficient to redirect the
2347resolution of all DocBook references to the specific catalog in
2348<code>/usr/share/xml/docbook.xml</code> this one in turn could delegate all
2349references for DocBook 4.2.1 to a specific catalog installed at the same time
2350as the DocBook resources on the local machine.</p>
2351
2352<h3><a name="reference">How to tune catalog usage:</a></h3>
2353
2354<p>The user can change the default catalog behaviour by redirecting queries
2355to its own set of catalogs, this can be done by setting the
2356<code>XML_CATALOG_FILES</code> environment variable to a list of catalogs, an
2357empty one should deactivate loading the default <code>/etc/xml/catalog</code>
2358default catalog</p>
2359
2360<h3><a name="validate">How to debug catalog processing:</a></h3>
2361
2362<p>Setting up the <code>XML_DEBUG_CATALOG</code> environment variable will
2363make libxml output debugging informations for each catalog operations, for
2364example:</p>
2365<pre>orchis:~/XML -&gt; xmllint --memory --noout test/ent2
2366warning: failed to load external entity "title.xml"
2367orchis:~/XML -&gt; export XML_DEBUG_CATALOG=
2368orchis:~/XML -&gt; xmllint --memory --noout test/ent2
2369Failed to parse catalog /etc/xml/catalog
2370Failed to parse catalog /etc/xml/catalog
2371warning: failed to load external entity "title.xml"
2372Catalogs cleanup
2373orchis:~/XML -&gt; </pre>
2374
2375<p>The test/ent2 references an entity, running the parser from memory makes
2376the base URI unavailable and the the "title.xml" entity cannot be loaded.
2377Setting up the debug environment variable allows to detect that an attempt is
2378made to load the <code>/etc/xml/catalog</code> but since it's not present the
2379resolution fails.</p>
2380
2381<p>But the most advanced way to debug XML catalog processing is to use the
2382<strong>xmlcatalog</strong> command shipped with libxml2, it allows to load
2383catalogs and make resolution queries to see what is going on. This is also
2384used for the regression tests:</p>
2385<pre>orchis:~/XML -&gt; ./xmlcatalog test/catalogs/docbook.xml \
2386 "-//OASIS//DTD DocBook XML V4.1.2//EN"
2387http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd
2388orchis:~/XML -&gt; </pre>
2389
2390<p>For debugging what is going on, adding one -v flags increase the verbosity
2391level to indicate the processing done (adding a second flag also indicate
2392what elements are recognized at parsing):</p>
2393<pre>orchis:~/XML -&gt; ./xmlcatalog -v test/catalogs/docbook.xml \
2394 "-//OASIS//DTD DocBook XML V4.1.2//EN"
2395Parsing catalog test/catalogs/docbook.xml's content
2396Found public match -//OASIS//DTD DocBook XML V4.1.2//EN
2397http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd
2398Catalogs cleanup
2399orchis:~/XML -&gt; </pre>
2400
2401<p>A shell interface is also available to debug and process multiple queries
2402(and for regression tests):</p>
2403<pre>orchis:~/XML -&gt; ./xmlcatalog -shell test/catalogs/docbook.xml \
2404 "-//OASIS//DTD DocBook XML V4.1.2//EN"
2405&gt; help
2406Commands available:
2407public PublicID: make a PUBLIC identifier lookup
2408system SystemID: make a SYSTEM identifier lookup
2409resolve PublicID SystemID: do a full resolver lookup
2410add 'type' 'orig' 'replace' : add an entry
2411del 'values' : remove values
2412dump: print the current catalog state
2413debug: increase the verbosity level
2414quiet: decrease the verbosity level
2415exit: quit the shell
2416&gt; public "-//OASIS//DTD DocBook XML V4.1.2//EN"
2417http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd
2418&gt; quit
2419orchis:~/XML -&gt; </pre>
2420
2421<p>This should be sufficient for most debugging purpose, this was actually
2422used heavily to debug the XML Catalog implementation itself.</p>
2423
2424<h3><a name="Declaring">How to create and maintain</a> catalogs:</h3>
2425
2426<p>Basically XML Catalogs are XML files, you can either use XML tools to
2427manage them or use <strong>xmlcatalog</strong> for this. The basic step is
2428to create a catalog the -create option provide this facility:</p>
2429<pre>orchis:~/XML -&gt; ./xmlcatalog --create tst.xml
2430&lt;?xml version="1.0"?&gt;
2431&lt;!DOCTYPE catalog PUBLIC "-//OASIS//DTD Entity Resolution XML Catalog V1.0//EN"
2432 "http://www.oasis-open.org/committees/entity/release/1.0/catalog.dtd"&gt;
2433&lt;catalog xmlns="urn:oasis:names:tc:entity:xmlns:xml:catalog"/&gt;
2434orchis:~/XML -&gt; </pre>
2435
2436<p>By default xmlcatalog does not overwrite the original catalog and save the
2437result on the standard output, this can be overridden using the -noout
2438option. The <code>-add</code> command allows to add entries in the
2439catalog:</p>
2440<pre>orchis:~/XML -&gt; ./xmlcatalog --noout --create --add "public" \
2441 "-//OASIS//DTD DocBook XML V4.1.2//EN" \
2442 http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd tst.xml
2443orchis:~/XML -&gt; cat tst.xml
2444&lt;?xml version="1.0"?&gt;
2445&lt;!DOCTYPE catalog PUBLIC "-//OASIS//DTD Entity Resolution XML Catalog V1.0//EN" \
2446 "http://www.oasis-open.org/committees/entity/release/1.0/catalog.dtd"&gt;
2447&lt;catalog xmlns="urn:oasis:names:tc:entity:xmlns:xml:catalog"&gt;
2448&lt;public publicId="-//OASIS//DTD DocBook XML V4.1.2//EN"
2449 uri="http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd"/&gt;
2450&lt;/catalog&gt;
2451orchis:~/XML -&gt; </pre>
2452
2453<p>The <code>-add</code> option will always take 3 parameters even if some of
2454the XML Catalog constructs (like nextCatalog) will have only a single
2455argument, just pass a third empty string, it will be ignored.</p>
2456
2457<p>Similarly the <code>-del</code> option remove matching entries from the
2458catalog:</p>
2459<pre>orchis:~/XML -&gt; ./xmlcatalog --del \
2460 "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd" tst.xml
2461&lt;?xml version="1.0"?&gt;
2462&lt;!DOCTYPE catalog PUBLIC "-//OASIS//DTD Entity Resolution XML Catalog V1.0//EN"
2463 "http://www.oasis-open.org/committees/entity/release/1.0/catalog.dtd"&gt;
2464&lt;catalog xmlns="urn:oasis:names:tc:entity:xmlns:xml:catalog"/&gt;
2465orchis:~/XML -&gt; </pre>
2466
2467<p>The catalog is now empty. Note that the matching of <code>-del</code> is
2468exact and would have worked in a similar fashion with the Public ID
2469string.</p>
2470
2471<p>This is rudimentary but should be sufficient to manage a not too complex
2472catalog tree of resources.</p>
2473
2474<h3><a name="implemento">The implementor corner quick review of the
2475API:</a></h3>
2476
2477<p>First, and like for every other module of libxml, there is an
2478automatically generated <a href="html/libxml-catalog.html">API page for
2479catalog support</a>.</p>
2480
2481<p>The header for the catalog interfaces should be included as:</p>
2482<pre>#include &lt;libxml/catalog.h&gt;</pre>
2483
2484<p>The API is voluntarily kept very simple. First it is not obvious that
2485applications really need access to it since it is the default behaviour of
2486libxml (Note: it is possible to completely override libxml default catalog by
2487using <a href="html/libxml-parser.html">xmlSetExternalEntityLoader</a> to
2488plug an application specific resolver).</p>
2489
2490<p>Basically libxml support 2 catalog lists:</p>
2491<ul>
2492 <li>the default one, global shared by all the application</li>
2493 <li>a per-document catalog, this one is built if the document uses the
2494 <code>oasis-xml-catalog</code> PIs to specify its own catalog list, it is
2495 associated to the parser context and destroyed when the parsing context
2496 is destroyed.</li>
2497</ul>
2498
2499<p>the document one will be used first if it exists.</p>
2500
2501<h4>Initialization routines:</h4>
2502
2503<p>xmlInitializeCatalog(), xmlLoadCatalog() and xmlLoadCatalogs() should be
2504used at startup to initialize the catalog, if the catalog should be
2505initialized with specific values xmlLoadCatalog() or xmlLoadCatalogs()
2506should be called before xmlInitializeCatalog() which would otherwise do a
2507default initialization first.</p>
2508
2509<p>The xmlCatalogAddLocal() call is used by the parser to grow the document
2510own catalog list if needed.</p>
2511
2512<h4>Preferences setup:</h4>
2513
2514<p>The XML Catalog spec requires the possibility to select default
2515preferences between public and system delegation,
2516xmlCatalogSetDefaultPrefer() allows this, xmlCatalogSetDefaults() and
2517xmlCatalogGetDefaults() allow to control if XML Catalogs resolution should
2518be forbidden, allowed for global catalog, for document catalog or both, the
2519default is to allow both.</p>
2520
2521<p>And of course xmlCatalogSetDebug() allows to generate debug messages
2522(through the xmlGenericError() mechanism).</p>
2523
2524<h4>Querying routines:</h4>
2525
2526<p>xmlCatalogResolve(), xmlCatalogResolveSystem(), xmlCatalogResolvePublic()
2527and xmlCatalogResolveURI() are relatively explicit if you read the XML
2528Catalog specification they correspond to section 7 algorithms, they should
2529also work if you have loaded an SGML catalog with a simplified semantic.</p>
2530
2531<p>xmlCatalogLocalResolve() and xmlCatalogLocalResolveURI() are the same but
2532operate on the document catalog list</p>
2533
2534<h4>Cleanup and Miscellaneous:</h4>
2535
2536<p>xmlCatalogCleanup() free-up the global catalog, xmlCatalogFreeLocal() is
2537the per-document equivalent.</p>
2538
2539<p>xmlCatalogAdd() and xmlCatalogRemove() are used to dynamically modify the
2540first catalog in the global list, and xmlCatalogDump() allows to dump a
2541catalog state, those routines are primarily designed for xmlcatalog, I'm not
2542sure that exposing more complex interfaces (like navigation ones) would be
2543really useful.</p>
2544
2545<p>The xmlParseCatalogFile() is a function used to load XML Catalog files,
2546it's similar as xmlParseFile() except it bypass all catalog lookups, it's
2547provided because this functionality may be useful for client tools.</p>
2548
2549<h4>threaded environments:</h4>
2550
2551<p>Since the catalog tree is built progressively, some care has been taken to
2552try to avoid troubles in multithreaded environments. The code is now thread
2553safe assuming that the libxml library has been compiled with threads
2554support.</p>
2555
2556<p></p>
2557
2558<h3><a name="Other">Other resources</a></h3>
2559
2560<p>The XML Catalog specification is relatively recent so there isn't much
2561literature to point at:</p>
2562<ul>
2563 <li>You can find an good rant from Norm Walsh about <a
2564 href="http://www.arbortext.com/Think_Tank/XML_Resources/Issue_Three/issue_three.html">the
2565 need for catalogs</a>, it provides a lot of context informations even if
2566 I don't agree with everything presented.</li>
2567 <li>An <a href="http://home.ccil.org/~cowan/XML/XCatalog.html">old XML
2568 catalog proposal</a> from John Cowan</li>
2569 <li>The <a href="http://www.rddl.org/">Resource Directory Description
2570 Language</a> (RDDL) another catalog system but more oriented toward
2571 providing metadata for XML namespaces.</li>
2572 <li>the page from the OASIS Technical <a
2573 href="http://www.oasis-open.org/committees/entity/">Committee on Entity
2574 Resolution</a> who maintains XML Catalog, you will find pointers to the
2575 specification update, some background and pointers to others tools
2576 providing XML Catalog support</li>
2577 <li>I have uploaded <a href="ftp://xmlsoft.org/test/dbk412catalog.tar.gz">a
2578 mall tarball</a> containing XML Catalogs for DocBook 4.1.2 which seems to
2579 work fine for me</li>
2580 <li>The <a href="http://www.xmlsoft.org/xmlcatalog_man.html">xmlcatalog
2581 manual page</a></li>
2582</ul>
2583
2584<p>If you have suggestions for corrections or additions, simply contact
2585me:</p>
2586
2587<h2><a name="library">The parser interfaces</a></h2>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]2588
2589<p>This section is directly intended to help programmers getting bootstrapped
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]2590using the XML library from the C language. It is not intended to be
2591extensive. I hope the automatically generated documents will provide the
2592completeness required, but as a separate set of documents. The interfaces of
2593the XML library are by principle low level, there is nearly zero abstraction.
2594Those interested in a higher level API should <a href="#DOM">look at
2595DOM</a>.</p>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]2596
Daniel Veillard9cb5ff42001-01-29 08:22:21 +0000[diff] [blame]2597<p>The <a href="html/libxml-parser.html">parser interfaces for XML</a> are
2598separated from the <a href="html/libxml-htmlparser.html">HTML parser
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]2599interfaces</a>. Let's have a look at how the XML parser can be called:</p>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]2600
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]2601<h3><a name="Invoking">Invoking the parser : the pull method</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]2602
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]2603<p>Usually, the first thing to do is to read an XML input. The parser accepts
2604documents either from in-memory strings or from files. The functions are
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]2605defined in "parser.h":</p>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]2606<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]2607 <dt><code>xmlDocPtr xmlParseMemory(char *buffer, int size);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]2608 <dd><p>Parse a null-terminated string containing the document.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]2609 </dd>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]2610</dl>
2611<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]2612 <dt><code>xmlDocPtr xmlParseFile(const char *filename);</code></dt>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]2613 <dd><p>Parse an XML document contained in a (possibly compressed)
2614 file.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]2615 </dd>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]2616</dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]2617
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]2618<p>The parser returns a pointer to the document structure (or NULL in case of
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]2619failure).</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]2620
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]2621<h3 id="Invoking1">Invoking the parser: the push method</h3>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]2622
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]2623<p>In order for the application to keep the control when the document is
2624being fetched (which is common for GUI based programs) libxml provides a push
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]2625interface, too, as of version 1.8.3. Here are the interface functions:</p>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]2626<pre>xmlParserCtxtPtr xmlCreatePushParserCtxt(xmlSAXHandlerPtr sax,
2627 void *user_data,
2628 const char *chunk,
2629 int size,
2630 const char *filename);
2631int xmlParseChunk (xmlParserCtxtPtr ctxt,
2632 const char *chunk,
2633 int size,
2634 int terminate);</pre>
2635
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]2636<p>and here is a simple example showing how to use the interface:</p>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]2637<pre> FILE *f;
2638
2639 f = fopen(filename, "r");
2640 if (f != NULL) {
2641 int res, size = 1024;
2642 char chars[1024];
2643 xmlParserCtxtPtr ctxt;
2644
2645 res = fread(chars, 1, 4, f);
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]2646 if (res &gt; 0) {
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]2647 ctxt = xmlCreatePushParserCtxt(NULL, NULL,
2648 chars, res, filename);
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]2649 while ((res = fread(chars, 1, size, f)) &gt; 0) {
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]2650 xmlParseChunk(ctxt, chars, res, 0);
2651 }
2652 xmlParseChunk(ctxt, chars, 0, 1);
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]2653 doc = ctxt-&gt;myDoc;
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]2654 xmlFreeParserCtxt(ctxt);
2655 }
2656 }</pre>
2657
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]2658<p>The HTML parser embedded into libxml also has a push interface; the
2659functions are just prefixed by "html" rather than "xml".</p>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]2660
2661<h3 id="Invoking2">Invoking the parser: the SAX interface</h3>
2662
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]2663<p>The tree-building interface makes the parser memory-hungry, first loading
2664the document in memory and then building the tree itself. Reading a document
2665without building the tree is possible using the SAX interfaces (see SAX.h and
2666<a href="http://www.daa.com.au/~james/gnome/xml-sax/xml-sax.html">James
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]2667Henstridge's documentation</a>). Note also that the push interface can be
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]2668limited to SAX: just use the two first arguments of
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]2669<code>xmlCreatePushParserCtxt()</code>.</p>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]2670
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]2671<h3><a name="Building">Building a tree from scratch</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]2672
2673<p>The other way to get an XML tree in memory is by building it. Basically
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]2674there is a set of functions dedicated to building new elements. (These are
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]2675also described in &lt;libxml/tree.h&gt;.) For example, here is a piece of
2676code that produces the XML document used in the previous examples:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]2677<pre> #include &lt;libxml/tree.h&gt;
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]2678 xmlDocPtr doc;
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]2679 xmlNodePtr tree, subtree;
2680
2681 doc = xmlNewDoc("1.0");
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]2682 doc-&gt;children = xmlNewDocNode(doc, NULL, "EXAMPLE", NULL);
2683 xmlSetProp(doc-&gt;children, "prop1", "gnome is great");
2684 xmlSetProp(doc-&gt;children, "prop2", "&amp; linux too");
2685 tree = xmlNewChild(doc-&gt;children, NULL, "head", NULL);
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]2686 subtree = xmlNewChild(tree, NULL, "title", "Welcome to Gnome");
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]2687 tree = xmlNewChild(doc-&gt;children, NULL, "chapter", NULL);
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]2688 subtree = xmlNewChild(tree, NULL, "title", "The Linux adventure");
2689 subtree = xmlNewChild(tree, NULL, "p", "bla bla bla ...");
2690 subtree = xmlNewChild(tree, NULL, "image", NULL);
2691 xmlSetProp(subtree, "href", "linus.gif");</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]2692
2693<p>Not really rocket science ...</p>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]2694
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]2695<h3><a name="Traversing">Traversing the tree</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]2696
Daniel Veillard9cb5ff42001-01-29 08:22:21 +0000[diff] [blame]2697<p>Basically by <a href="html/libxml-tree.html">including "tree.h"</a> your
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]2698code has access to the internal structure of all the elements of the tree.
2699The names should be somewhat simple like <strong>parent</strong>,
Daniel Veillard306be992000-07-03 12:38:45 +0000[diff] [blame]2700<strong>children</strong>, <strong>next</strong>, <strong>prev</strong>,
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]2701<strong>properties</strong>, etc... For example, still with the previous
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]2702example:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]2703<pre><code>doc-&gt;children-&gt;children-&gt;children</code></pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]2704
2705<p>points to the title element,</p>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]2706<pre>doc-&gt;children-&gt;children-&gt;next-&gt;children-&gt;children</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]2707
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]2708<p>points to the text node containing the chapter title "The Linux
2709adventure".</p>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]2710
Daniel Veillardb24054a1999-12-18 15:32:46 +0000[diff] [blame]2711<p><strong>NOTE</strong>: XML allows <em>PI</em>s and <em>comments</em> to be
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]2712present before the document root, so <code>doc-&gt;children</code> may point
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]2713to an element which is not the document Root Element; a function
Daniel Veillard5cb5ab81999-12-21 15:35:29 +0000[diff] [blame]2714<code>xmlDocGetRootElement()</code> was added for this purpose.</p>
Daniel Veillardb24054a1999-12-18 15:32:46 +0000[diff] [blame]2715
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]2716<h3><a name="Modifying">Modifying the tree</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]2717
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]2718<p>Functions are provided for reading and writing the document content. Here
Daniel Veillard9cb5ff42001-01-29 08:22:21 +0000[diff] [blame]2719is an excerpt from the <a href="html/libxml-tree.html">tree API</a>:</p>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]2720<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +0000[diff] [blame]2721 <dt><code>xmlAttrPtr xmlSetProp(xmlNodePtr node, const xmlChar *name, const
2722 xmlChar *value);</code></dt>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]2723 <dd><p>This sets (or changes) an attribute carried by an ELEMENT node.
2724 The value can be NULL.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]2725 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]2726</dl>
2727<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +0000[diff] [blame]2728 <dt><code>const xmlChar *xmlGetProp(xmlNodePtr node, const xmlChar
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]2729 *name);</code></dt>
Daniel Veillardc92c3042000-09-29 02:42:04 +0000[diff] [blame]2730 <dd><p>This function returns a pointer to new copy of the property
2731 content. Note that the user must deallocate the result.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]2732 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]2733</dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]2734
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]2735<p>Two functions are provided for reading and writing the text associated
2736with elements:</p>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]2737<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +0000[diff] [blame]2738 <dt><code>xmlNodePtr xmlStringGetNodeList(xmlDocPtr doc, const xmlChar
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]2739 *value);</code></dt>
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]2740 <dd><p>This function takes an "external" string and converts it to one
2741 text node or possibly to a list of entity and text nodes. All
2742 non-predefined entity references like &amp;Gnome; will be stored
2743 internally as entity nodes, hence the result of the function may not be
2744 a single node.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]2745 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]2746</dl>
2747<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +0000[diff] [blame]2748 <dt><code>xmlChar *xmlNodeListGetString(xmlDocPtr doc, xmlNodePtr list, int
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]2749 inLine);</code></dt>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]2750 <dd><p>This function is the inverse of
2751 <code>xmlStringGetNodeList()</code>. It generates a new string
2752 containing the content of the text and entity nodes. Note the extra
2753 argument inLine. If this argument is set to 1, the function will expand
2754 entity references. For example, instead of returning the &amp;Gnome;
2755 XML encoding in the string, it will substitute it with its value (say,
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]2756 "GNU Network Object Model Environment").</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]2757 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]2758</dl>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]2759
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]2760<h3><a name="Saving">Saving a tree</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]2761
2762<p>Basically 3 options are possible:</p>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]2763<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +0000[diff] [blame]2764 <dt><code>void xmlDocDumpMemory(xmlDocPtr cur, xmlChar**mem, int
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]2765 *size);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]2766 <dd><p>Returns a buffer into which the document has been saved.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]2767 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]2768</dl>
2769<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]2770 <dt><code>extern void xmlDocDump(FILE *f, xmlDocPtr doc);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]2771 <dd><p>Dumps a document to an open file descriptor.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]2772 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]2773</dl>
2774<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]2775 <dt><code>int xmlSaveFile(const char *filename, xmlDocPtr cur);</code></dt>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]2776 <dd><p>Saves the document to a file. In this case, the compression
2777 interface is triggered if it has been turned on.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]2778 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]2779</dl>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]2780
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]2781<h3><a name="Compressio">Compression</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]2782
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]2783<p>The library transparently handles compression when doing file-based
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]2784accesses. The level of compression on saves can be turned on either globally
2785or individually for one file:</p>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]2786<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]2787 <dt><code>int xmlGetDocCompressMode (xmlDocPtr doc);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]2788 <dd><p>Gets the document compression ratio (0-9).</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]2789 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]2790</dl>
2791<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]2792 <dt><code>void xmlSetDocCompressMode (xmlDocPtr doc, int mode);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]2793 <dd><p>Sets the document compression ratio.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]2794 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]2795</dl>
2796<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]2797 <dt><code>int xmlGetCompressMode(void);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]2798 <dd><p>Gets the default compression ratio.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]2799 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]2800</dl>
2801<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]2802 <dt><code>void xmlSetCompressMode(int mode);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]2803 <dd><p>Sets the default compression ratio.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]2804 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]2805</dl>
2806
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]2807<h2><a name="Entities">Entities or no entities</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]2808
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]2809<p>Entities in principle are similar to simple C macros. An entity defines an
2810abbreviation for a given string that you can reuse many times throughout the
2811content of your document. Entities are especially useful when a given string
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]2812may occur frequently within a document, or to confine the change needed to a
2813document to a restricted area in the internal subset of the document (at the
2814beginning). Example:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]2815<pre>1 &lt;?xml version="1.0"?&gt;
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]28162 &lt;!DOCTYPE EXAMPLE SYSTEM "example.dtd" [
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]28173 &lt;!ENTITY xml "Extensible Markup Language"&gt;
28184 ]&gt;
28195 &lt;EXAMPLE&gt;
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]28206 &amp;xml;
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]28217 &lt;/EXAMPLE&gt;</pre>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]2822
2823<p>Line 3 declares the xml entity. Line 6 uses the xml entity, by prefixing
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]2824its name with '&amp;' and following it by ';' without any spaces added. There
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]2825are 5 predefined entities in libxml allowing you to escape charaters with
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]2826predefined meaning in some parts of the xml document content:
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]2827<strong>&amp;lt;</strong> for the character '&lt;', <strong>&amp;gt;</strong>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]2828for the character '&gt;', <strong>&amp;apos;</strong> for the character ''',
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]2829<strong>&amp;quot;</strong> for the character '"', and
2830<strong>&amp;amp;</strong> for the character '&amp;'.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]2831
2832<p>One of the problems related to entities is that you may want the parser to
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]2833substitute an entity's content so that you can see the replacement text in
2834your application. Or you may prefer to keep entity references as such in the
2835content to be able to save the document back without losing this usually
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]2836precious information (if the user went through the pain of explicitly
2837defining entities, he may have a a rather negative attitude if you blindly
2838susbtitute them as saving time). The <a
Daniel Veillard9cb5ff42001-01-29 08:22:21 +0000[diff] [blame]2839href="html/libxml-parser.html#XMLSUBSTITUTEENTITIESDEFAULT">xmlSubstituteEntitiesDefault()</a>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]2840function allows you to check and change the behaviour, which is to not
2841substitute entities by default.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]2842
2843<p>Here is the DOM tree built by libxml for the previous document in the
2844default case:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]2845<pre>/gnome/src/gnome-xml -&gt; ./xmllint --debug test/ent1
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]2846DOCUMENT
2847version=1.0
2848 ELEMENT EXAMPLE
2849 TEXT
2850 content=
2851 ENTITY_REF
2852 INTERNAL_GENERAL_ENTITY xml
2853 content=Extensible Markup Language
2854 TEXT
2855 content=</pre>
2856
2857<p>And here is the result when substituting entities:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]2858<pre>/gnome/src/gnome-xml -&gt; ./tester --debug --noent test/ent1
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]2859DOCUMENT
2860version=1.0
2861 ELEMENT EXAMPLE
2862 TEXT
2863 content= Extensible Markup Language</pre>
2864
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]2865<p>So, entities or no entities? Basically, it depends on your use case. I
2866suggest that you keep the non-substituting default behaviour and avoid using
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]2867entities in your XML document or data if you are not willing to handle the
2868entity references elements in the DOM tree.</p>
2869
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]2870<p>Note that at save time libxml enforces the conversion of the predefined
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]2871entities where necessary to prevent well-formedness problems, and will also
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]2872transparently replace those with chars (i.e. it will not generate entity
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]2873reference elements in the DOM tree or call the reference() SAX callback when
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]2874finding them in the input).</p>
2875
Daniel Veillard7b9c4b72000-08-25 16:26:50 +0000[diff] [blame]2876<p><span style="background-color: #FF0000">WARNING</span>: handling entities
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]2877on top of the libxml SAX interface is difficult!!! If you plan to use
Daniel Veillard7b9c4b72000-08-25 16:26:50 +0000[diff] [blame]2878non-predefined entities in your documents, then the learning cuvre to handle
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]2879then using the SAX API may be long. If you plan to use complex documents, I
Daniel Veillard7b9c4b72000-08-25 16:26:50 +0000[diff] [blame]2880strongly suggest you consider using the DOM interface instead and let libxml
Daniel Veillard8c6d6af2000-08-25 17:14:13 +0000[diff] [blame]2881deal with the complexity rather than trying to do it yourself.</p>
Daniel Veillard7b9c4b72000-08-25 16:26:50 +0000[diff] [blame]2882
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]2883<h2><a name="Namespaces">Namespaces</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]2884
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]2885<p>The libxml library implements <a
2886href="http://www.w3.org/TR/REC-xml-names/">XML namespaces</a> support by
2887recognizing namespace contructs in the input, and does namespace lookup
2888automatically when building the DOM tree. A namespace declaration is
2889associated with an in-memory structure and all elements or attributes within
2890that namespace point to it. Hence testing the namespace is a simple and fast
2891equality operation at the user level.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]2892
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]2893<p>I suggest that people using libxml use a namespace, and declare it in the
2894root element of their document as the default namespace. Then they don't need
2895to use the prefix in the content but we will have a basis for future semantic
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]2896refinement and merging of data from different sources. This doesn't increase
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]2897the size of the XML output significantly, but significantly increases its
2898value in the long-term. Example:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]2899<pre>&lt;mydoc xmlns="http://mydoc.example.org/schemas/"&gt;
2900 &lt;elem1&gt;...&lt;/elem1&gt;
2901 &lt;elem2&gt;...&lt;/elem2&gt;
2902&lt;/mydoc&gt;</pre>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]2903
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]2904<p>The namespace value has to be an absolute URL, but the URL doesn't have to
2905point to any existing resource on the Web. It will bind all the element and
2906atributes with that URL. I suggest to use an URL within a domain you control,
2907and that the URL should contain some kind of version information if possible.
2908For example, <code>"http://www.gnome.org/gnumeric/1.0/"</code> is a good
2909namespace scheme.</p>
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]2910
2911<p>Then when you load a file, make sure that a namespace carrying the
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]2912version-independent prefix is installed on the root element of your document,
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]2913and if the version information don't match something you know, warn the user
2914and be liberal in what you accept as the input. Also do *not* try to base
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]2915namespace checking on the prefix value. &lt;foo:text&gt; may be exactly the
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]2916same as &lt;bar:text&gt; in another document. What really matters is the URI
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]2917associated with the element or the attribute, not the prefix string (which is
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]2918just a shortcut for the full URI). In libxml, element and attributes have an
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]2919<code>ns</code> field pointing to an xmlNs structure detailing the namespace
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]2920prefix and its URI.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]2921
2922<p>@@Interfaces@@</p>
2923
2924<p>@@Examples@@</p>
2925
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]2926<p>Usually people object to using namespaces together with validity checking.
2927I will try to make sure that using namespaces won't break validity checking,
2928so even if you plan to use or currently are using validation I strongly
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]2929suggest adding namespaces to your document. A default namespace scheme
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]2930<code>xmlns="http://...."</code> should not break validity even on less
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]2931flexible parsers. Using namespaces to mix and differentiate content coming
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]2932from multiple DTDs will certainly break current validation schemes. I will
2933try to provide ways to do this, but this may not be portable or
2934standardized.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]2935
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2936<h2><a name="Upgrading">Upgrading 1.x code</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]2937
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2938<p>Incompatible changes:</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]2939
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2940<p>Version 2 of libxml is the first version introducing serious backward
2941incompatible changes. The main goals were:</p>
2942<ul>
2943 <li>a general cleanup. A number of mistakes inherited from the very early
2944 versions couldn't be changed due to compatibility constraints. Example
2945 the "childs" element in the nodes.</li>
2946 <li>Uniformization of the various nodes, at least for their header and link
2947 parts (doc, parent, children, prev, next), the goal is a simpler
2948 programming model and simplifying the task of the DOM implementors.</li>
2949 <li>better conformances to the XML specification, for example version 1.x
2950 had an heuristic to try to detect ignorable white spaces. As a result the
2951 SAX event generated were ignorableWhitespace() while the spec requires
2952 character() in that case. This also mean that a number of DOM node
2953 containing blank text may populate the DOM tree which were not present
2954 before.</li>
2955</ul>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]2956
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2957<h3>How to fix libxml-1.x code:</h3>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]2958
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2959<p>So client code of libxml designed to run with version 1.x may have to be
2960changed to compile against version 2.x of libxml. Here is a list of changes
2961that I have collected, they may not be sufficient, so in case you find other
2962change which are required, <a href="mailto:Daniel.Ïeillardw3.org">drop me a
2963mail</a>:</p>
2964<ol>
2965 <li>The package name have changed from libxml to libxml2, the library name
2966 is now -lxml2 . There is a new xml2-config script which should be used to
2967 select the right parameters libxml2</li>
2968 <li>Node <strong>childs</strong> field has been renamed
2969 <strong>children</strong> so s/childs/children/g should be applied
2970 (probablility of having "childs" anywere else is close to 0+</li>
2971 <li>The document don't have anymore a <strong>root</strong> element it has
2972 been replaced by <strong>children</strong> and usually you will get a
2973 list of element here. For example a Dtd element for the internal subset
2974 and it's declaration may be found in that list, as well as processing
2975 instructions or comments found before or after the document root element.
2976 Use <strong>xmlDocGetRootElement(doc)</strong> to get the root element of
2977 a document. Alternatively if you are sure to not reference Dtds nor have
2978 PIs or comments before or after the root element
2979 s/-&gt;root/-&gt;children/g will probably do it.</li>
2980 <li>The white space issue, this one is more complex, unless special case of
2981 validating parsing, the line breaks and spaces usually used for indenting
2982 and formatting the document content becomes significant. So they are
2983 reported by SAX and if your using the DOM tree, corresponding nodes are
2984 generated. Too approach can be taken:
2985 <ol>
2986 <li>lazy one, use the compatibility call
2987 <strong>xmlKeepBlanksDefault(0)</strong> but be aware that you are
2988 relying on a special (and possibly broken) set of heuristics of
2989 libxml to detect ignorable blanks. Don't complain if it breaks or
2990 make your application not 100% clean w.r.t. to it's input.</li>
2991 <li>the Right Way: change you code to accept possibly unsignificant
2992 blanks characters, or have your tree populated with weird blank text
2993 nodes. You can spot them using the comodity function
2994 <strong>xmlIsBlankNode(node)</strong> returning 1 for such blank
2995 nodes.</li>
2996 </ol>
2997 <p>Note also that with the new default the output functions don't add any
2998 extra indentation when saving a tree in order to be able to round trip
2999 (read and save) without inflating the document with extra formatting
3000 chars.</p>
3001 </li>
3002 <li>The include path has changed to $prefix/libxml/ and the includes
3003 themselves uses this new prefix in includes instructions... If you are
3004 using (as expected) the
3005 <pre>xml2-config --cflags</pre>
3006 <p>output to generate you compile commands this will probably work out of
3007 the box</p>
3008 </li>
3009 <li>xmlDetectCharEncoding takes an extra argument indicating the lenght in
3010 byte of the head of the document available for character detection.</li>
3011</ol>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3012
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3013<h3>Ensuring both libxml-1.x and libxml-2.x compatibility</h3>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3014
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3015<p>Two new version of libxml (1.8.11) and libxml2 (2.3.4) have been released
3016to allow smoth upgrade of existing libxml v1code while retaining
3017compatibility. They offers the following:</p>
3018<ol>
3019 <li>similar include naming, one should use
3020 <strong>#include&lt;libxml/...&gt;</strong> in both cases.</li>
3021 <li>similar identifiers defined via macros for the child and root fields:
3022 respectively <strong>xmlChildrenNode</strong> and
3023 <strong>xmlRootNode</strong></li>
3024 <li>a new macro <strong>LIBXML_TEST_VERSION</strong> which should be
3025 inserted once in the client code</li>
3026</ol>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3027
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3028<p>So the roadmap to upgrade your existing libxml applications is the
3029following:</p>
3030<ol>
3031 <li>install the libxml-1.8.8 (and libxml-devel-1.8.8) packages</li>
3032 <li>find all occurences where the xmlDoc <strong>root</strong> field is
3033 used and change it to <strong>xmlRootNode</strong></li>
3034 <li>similary find all occurences where the xmlNode <strong>childs</strong>
3035 field is used and change it to <strong>xmlChildrenNode</strong></li>
3036 <li>add a <strong>LIBXML_TEST_VERSION</strong> macro somewhere in your
3037 <strong>main()</strong> or in the library init entry point</li>
3038 <li>Recompile, check compatibility, it should still work</li>
3039 <li>Change your configure script to look first for xml2-config and fallback
3040 using xml-config . Use the --cflags and --libs ouptut of the command as
3041 the Include and Linking parameters needed to use libxml.</li>
3042 <li>install libxml2-2.3.x and libxml2-devel-2.3.x (libxml-1.8.y and
3043 libxml-devel-1.8.y can be kept simultaneously)</li>
3044 <li>remove your config.cache, relaunch your configuration mechanism, and
3045 recompile, if steps 2 and 3 were done right it should compile as-is</li>
3046 <li>Test that your application is still running correctly, if not this may
3047 be due to extra empty nodes due to formating spaces being kept in libxml2
3048 contrary to libxml1, in that case insert xmlKeepBlanksDefault(1) in your
3049 code before calling the parser (next to
3050 <strong>LIBXML_TEST_VERSION</strong> is a fine place).</li>
3051</ol>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3052
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3053<p>Following those steps should work. It worked for some of my own code.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3054
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3055<p>Let me put some emphasis on the fact that there is far more changes from
3056libxml 1.x to 2.x than the ones you may have to patch for. The overall code
3057has been considerably cleaned up and the conformance to the XML specification
3058has been drastically improved too. Don't take those changes as an excuse to
3059not upgrade, it may cost a lot on the long term ...</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3060
Daniel Veillard52dcab32001-10-30 12:51:17 +0000[diff] [blame]3061<h2><a name="Thread">Thread safety</a></h2>
3062
3063<p>Starting with 2.4.7, libxml makes provisions to ensure that concurent
3064threads can safely work in parallel parsing different documents. There is
3065however a couple of things to do to ensure it:</p>
3066<ul>
3067 <li>configure the library accordingly using the --with-threads options</li>
3068 <li>call xmlInitParser() in the "main" thread before using any of the
3069 libxml API (except possibly selecting a different memory allocator)</li>
3070</ul>
3071
3072<p>Note that the thread safety cannot be ensured for multiple threads sharing
3073the same document, the locking must be done at the application level, libxml
3074exports a basic mutex and reentrant mutexes API in &lt;libxml/threads.h&gt;.
3075The parts of the library checked for thread safety are:</p>
3076<ul>
3077 <li>concurrent loading</li>
3078 <li>file access resolution</li>
3079 <li>catalog access</li>
3080 <li>catalog building</li>
3081 <li>entities lookup/accesses</li>
3082 <li>validation</li>
3083 <li>global variables per-thread override</li>
3084 <li>memory handling</li>
3085</ul>
3086
3087<p>XPath is supposed to be thread safe now, but this wasn't tested
3088seriously.</p>
3089
Daniel Veillard35008381999-10-25 13:15:52 +0000[diff] [blame]3090<h2><a name="DOM"></a><a name="Principles">DOM Principles</a></h2>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3091
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3092<p><a href="http://www.w3.org/DOM/">DOM</a> stands for the <em>Document
3093Object Model</em>; this is an API for accessing XML or HTML structured
3094documents. Native support for DOM in Gnome is on the way (module gnome-dom),
3095and will be based on gnome-xml. This will be a far cleaner interface to
3096manipulate XML files within Gnome since it won't expose the internal
3097structure.</p>
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3098
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3099<p>The current DOM implementation on top of libxml is the <a
Daniel Veillarda47fb3d2001-03-25 17:23:49 +0000[diff] [blame]3100href="http://cvs.gnome.org/lxr/source/gdome2/">gdome2 Gnome module</a>, this
3101is a full DOM interface, thanks to Paolo Casarini, check the <a
3102href="http://www.cs.unibo.it/~casarini/gdome2/">Gdome2 homepage</a> for more
3103informations.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3104
Daniel Veillard35008381999-10-25 13:15:52 +0000[diff] [blame]3105<h2><a name="Example"></a><a name="real">A real example</a></h2>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3106
3107<p>Here is a real size example, where the actual content of the application
3108data is not kept in the DOM tree but uses internal structures. It is based on
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3109a proposal to keep a database of jobs related to Gnome, with an XML based
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3110storage structure. Here is an <a href="gjobs.xml">XML encoded jobs
3111base</a>:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3112<pre>&lt;?xml version="1.0"?&gt;
3113&lt;gjob:Helping xmlns:gjob="http://www.gnome.org/some-location"&gt;
3114 &lt;gjob:Jobs&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3115
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3116 &lt;gjob:Job&gt;
3117 &lt;gjob:Project ID="3"/&gt;
3118 &lt;gjob:Application&gt;GBackup&lt;/gjob:Application&gt;
3119 &lt;gjob:Category&gt;Development&lt;/gjob:Category&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3120
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3121 &lt;gjob:Update&gt;
3122 &lt;gjob:Status&gt;Open&lt;/gjob:Status&gt;
3123 &lt;gjob:Modified&gt;Mon, 07 Jun 1999 20:27:45 -0400 MET DST&lt;/gjob:Modified&gt;
3124 &lt;gjob:Salary&gt;USD 0.00&lt;/gjob:Salary&gt;
3125 &lt;/gjob:Update&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3126
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3127 &lt;gjob:Developers&gt;
3128 &lt;gjob:Developer&gt;
3129 &lt;/gjob:Developer&gt;
3130 &lt;/gjob:Developers&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3131
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3132 &lt;gjob:Contact&gt;
3133 &lt;gjob:Person&gt;Nathan Clemons&lt;/gjob:Person&gt;
3134 &lt;gjob:Email&gt;nathan@windsofstorm.net&lt;/gjob:Email&gt;
3135 &lt;gjob:Company&gt;
3136 &lt;/gjob:Company&gt;
3137 &lt;gjob:Organisation&gt;
3138 &lt;/gjob:Organisation&gt;
3139 &lt;gjob:Webpage&gt;
3140 &lt;/gjob:Webpage&gt;
3141 &lt;gjob:Snailmail&gt;
3142 &lt;/gjob:Snailmail&gt;
3143 &lt;gjob:Phone&gt;
3144 &lt;/gjob:Phone&gt;
3145 &lt;/gjob:Contact&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3146
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3147 &lt;gjob:Requirements&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3148 The program should be released as free software, under the GPL.
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3149 &lt;/gjob:Requirements&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3150
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3151 &lt;gjob:Skills&gt;
3152 &lt;/gjob:Skills&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3153
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3154 &lt;gjob:Details&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3155 A GNOME based system that will allow a superuser to configure
3156 compressed and uncompressed files and/or file systems to be backed
3157 up with a supported media in the system. This should be able to
3158 perform via find commands generating a list of files that are passed
3159 to tar, dd, cpio, cp, gzip, etc., to be directed to the tape machine
3160 or via operations performed on the filesystem itself. Email
3161 notification and GUI status display very important.
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3162 &lt;/gjob:Details&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3163
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3164 &lt;/gjob:Job&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3165
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3166 &lt;/gjob:Jobs&gt;
3167&lt;/gjob:Helping&gt;</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3168
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3169<p>While loading the XML file into an internal DOM tree is a matter of
3170calling only a couple of functions, browsing the tree to gather the ata and
3171generate the internal structures is harder, and more error prone.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3172
3173<p>The suggested principle is to be tolerant with respect to the input
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3174structure. For example, the ordering of the attributes is not significant,
3175the XML specification is clear about it. It's also usually a good idea not to
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]3176depend on the order of the children of a given node, unless it really makes
3177things harder. Here is some code to parse the information for a person:</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3178<pre>/*
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3179 * A person record
3180 */
3181typedef struct person {
3182 char *name;
3183 char *email;
3184 char *company;
3185 char *organisation;
3186 char *smail;
3187 char *webPage;
3188 char *phone;
3189} person, *personPtr;
3190
3191/*
3192 * And the code needed to parse it
3193 */
3194personPtr parsePerson(xmlDocPtr doc, xmlNsPtr ns, xmlNodePtr cur) {
3195 personPtr ret = NULL;
3196
3197DEBUG("parsePerson\n");
3198 /*
3199 * allocate the struct
3200 */
3201 ret = (personPtr) malloc(sizeof(person));
3202 if (ret == NULL) {
3203 fprintf(stderr,"out of memory\n");
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3204 return(NULL);
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3205 }
3206 memset(ret, 0, sizeof(person));
3207
3208 /* We don't care what the top level element name is */
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3209 cur = cur-&gt;xmlChildrenNode;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3210 while (cur != NULL) {
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3211 if ((!strcmp(cur-&gt;name, "Person")) &amp;&amp; (cur-&gt;ns == ns))
3212 ret-&gt;name = xmlNodeListGetString(doc, cur-&gt;xmlChildrenNode, 1);
3213 if ((!strcmp(cur-&gt;name, "Email")) &amp;&amp; (cur-&gt;ns == ns))
3214 ret-&gt;email = xmlNodeListGetString(doc, cur-&gt;xmlChildrenNode, 1);
3215 cur = cur-&gt;next;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3216 }
3217
3218 return(ret);
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3219}</pre>
3220
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3221<p>Here are a couple of things to notice:</p>
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3222<ul>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3223 <li>Usually a recursive parsing style is the more convenient one: XML data
3224 is by nature subject to repetitive constructs and usually exibits highly
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3225 stuctured patterns.</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3226 <li>The two arguments of type <em>xmlDocPtr</em> and <em>xmlNsPtr</em>,
3227 i.e. the pointer to the global XML document and the namespace reserved to
3228 the application. Document wide information are needed for example to
3229 decode entities and it's a good coding practice to define a namespace for
3230 your application set of data and test that the element and attributes
3231 you're analyzing actually pertains to your application space. This is
3232 done by a simple equality test (cur-&gt;ns == ns).</li>
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]3233 <li>To retrieve text and attributes value, you can use the function
3234 <em>xmlNodeListGetString</em> to gather all the text and entity reference
3235 nodes generated by the DOM output and produce an single text string.</li>
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3236</ul>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3237
3238<p>Here is another piece of code used to parse another level of the
3239structure:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3240<pre>#include &lt;libxml/tree.h&gt;
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]3241/*
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3242 * a Description for a Job
3243 */
3244typedef struct job {
3245 char *projectID;
3246 char *application;
3247 char *category;
3248 personPtr contact;
3249 int nbDevelopers;
3250 personPtr developers[100]; /* using dynamic alloc is left as an exercise */
3251} job, *jobPtr;
3252
3253/*
3254 * And the code needed to parse it
3255 */
3256jobPtr parseJob(xmlDocPtr doc, xmlNsPtr ns, xmlNodePtr cur) {
3257 jobPtr ret = NULL;
3258
3259DEBUG("parseJob\n");
3260 /*
3261 * allocate the struct
3262 */
3263 ret = (jobPtr) malloc(sizeof(job));
3264 if (ret == NULL) {
3265 fprintf(stderr,"out of memory\n");
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3266 return(NULL);
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3267 }
3268 memset(ret, 0, sizeof(job));
3269
3270 /* We don't care what the top level element name is */
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3271 cur = cur-&gt;xmlChildrenNode;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3272 while (cur != NULL) {
3273
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3274 if ((!strcmp(cur-&gt;name, "Project")) &amp;&amp; (cur-&gt;ns == ns)) {
3275 ret-&gt;projectID = xmlGetProp(cur, "ID");
3276 if (ret-&gt;projectID == NULL) {
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3277 fprintf(stderr, "Project has no ID\n");
3278 }
3279 }
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3280 if ((!strcmp(cur-&gt;name, "Application")) &amp;&amp; (cur-&gt;ns == ns))
3281 ret-&gt;application = xmlNodeListGetString(doc, cur-&gt;xmlChildrenNode, 1);
3282 if ((!strcmp(cur-&gt;name, "Category")) &amp;&amp; (cur-&gt;ns == ns))
3283 ret-&gt;category = xmlNodeListGetString(doc, cur-&gt;xmlChildrenNode, 1);
3284 if ((!strcmp(cur-&gt;name, "Contact")) &amp;&amp; (cur-&gt;ns == ns))
3285 ret-&gt;contact = parsePerson(doc, ns, cur);
3286 cur = cur-&gt;next;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3287 }
3288
3289 return(ret);
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3290}</pre>
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3291
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]3292<p>Once you are used to it, writing this kind of code is quite simple, but
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3293boring. Ultimately, it could be possble to write stubbers taking either C
3294data structure definitions, a set of XML examples or an XML DTD and produce
3295the code needed to import and export the content between C data and XML
3296storage. This is left as an exercise to the reader :-)</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3297
Daniel Veillard6f0adb52000-07-03 11:41:26 +0000[diff] [blame]3298<p>Feel free to use <a href="example/gjobread.c">the code for the full C
3299parsing example</a> as a template, it is also available with Makefile in the
3300Gnome CVS base under gnome-xml/example</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3301
Daniel Veillardc310d562000-06-23 18:32:15 +0000[diff] [blame]3302<h2><a name="Contributi">Contributions</a></h2>
3303<ul>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3304 <li>Bjorn Reese, William Brack and Thomas Broyer have provided a number of
3305 patches, Gary Pennington worked on the validation API, threading support
3306 and Solaris port.</li>
3307 <li>John Fleck helps maintaining the documentation and man pages.</li>
Daniel Veillardc6271d22001-10-27 07:50:58 +0000[diff] [blame]3308 <li><a href="mailto:ari@lusis.org">Ari Johnson</a>
Daniel Veillard51095312001-10-28 18:51:57 +0000[diff] [blame]3309 provides a C++ wrapper for libxml:<br>
Daniel Veillardc6271d22001-10-27 07:50:58 +0000[diff] [blame]3310 Website: <a
3311 href="http://lusis.org/~ari/xml++/">http://lusis.org/~ari/xml++/</a><br>
3312 Download: <a
Daniel Veillard51095312001-10-28 18:51:57 +0000[diff] [blame]3313 href="http://lusis.org/~ari/xml++/libxml++.tar.gz">http://lusis.org/~ari/xml++/libxml++.tar.gz</a></li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3314 <li><a href="mailto:izlatkovic@daenet.de">Igor Zlatkovic</a>
3315 is now the maintainer of the Windows port, <a
Daniel Veillard95189532001-07-26 18:30:26 +0000[diff] [blame]3316 href="http://www.fh-frankfurt.de/~igor/projects/libxml/index.html">he
3317 provides binaries</a></li>
Daniel Veillardc9484202001-10-24 12:35:52 +0000[diff] [blame]3318 <li><a href="mailto:Gary.Pennington@sun.com">Gary Pennington</a>
Daniel Veillarddb9dfd92001-11-26 17:25:02 +0000[diff] [blame]3319 provides <a href="http://garypennington.net/libxml2/">Solaris
Daniel Veillard0a702dc2001-10-19 14:50:57 +0000[diff] [blame]3320 binaries</a></li>
Daniel Veillarde356c282001-03-10 12:32:04 +0000[diff] [blame]3321 <li><a
3322 href="http://mail.gnome.org/archives/xml/2001-March/msg00014.html">Matt
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3323 Sergeant</a>
3324 developped <a href="http://axkit.org/download/">XML::LibXSLT</a>, a perl
3325 wrapper for libxml2/libxslt as part of the <a
3326 href="http://axkit.com/">AxKit XML application server</a></li>
3327 <li><a href="mailto:fnatter@gmx.net">Felix Natter</a>
3328 and <a href="mailto:geertk@ai.rug.nl">Geert Kloosterman</a> provide <a
Daniel Veillardca989762001-06-23 17:39:29 +0000[diff] [blame]3329 href="libxml-doc.el">an emacs module</a> to lookup libxml(2) functions
Daniel Veillard3f6f7f62000-06-30 17:58:25 +0000[diff] [blame]3330 documentation</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3331 <li><a href="mailto:sherwin@nlm.nih.gov">Ziying Sherwin</a>
3332 provided <a href="http://xmlsoft.org/messages/0488.html">man
3333 pages</a></li>
Daniel Veillard5168dbf2001-07-07 00:18:23 +0000[diff] [blame]3334 <li>there is a module for <a
3335 href="http://acs-misc.sourceforge.net/nsxml.html">libxml/libxslt support
3336 in OpenNSD/AOLServer</a></li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3337 <li><a href="mailto:dkuhlman@cutter.rexx.com">Dave Kuhlman</a>
3338 provides libxml/libxslt <a href="http://www.rexx.com/~dkuhlman">wrappers
3339 for Python</a></li>
Daniel Veillard1aadc442001-11-28 13:10:32 +0000[diff] [blame]3340 <li>Petr Kozelka provides <a
3341 href="http://sourceforge.net/projects/libxml2-pas">Pascal units to glue
3342 libxml2</a> with Kylix and Delphi and other Pascal compilers</li>
Daniel Veillardc310d562000-06-23 18:32:15 +0000[diff] [blame]3343</ul>
3344
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3345<p></p>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]3346</body>
3347</html>