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blob: 2631fe93334045e562f502831d9226a84ef16c44 [file] [log] [blame]
Daniel Veillard09ab7e12001-07-10 15:49:44 +0000[diff] [blame]1<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
2 "http://www.w3.org/TR/html4/loose.dtd">
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]3<html>
4<head>
Daniel Veillardec78c0f2000-08-25 10:25:23 +0000[diff] [blame]5 <title>The XML C library for Gnome</title>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]6 <meta name="GENERATOR" content="amaya 5.1">
Daniel Veillardb24054a1999-12-18 15:32:46 +0000[diff] [blame]7 <meta http-equiv="Content-Type" content="text/html">
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]8</head>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]9
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]10<body bgcolor="#ffffff">
Daniel Veillardec78c0f2000-08-25 10:25:23 +0000[diff] [blame]11<h1 align="center">The XML C library for Gnome</h1>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]12
Daniel Veillard9c466822001-10-25 12:03:39 +0000[diff] [blame]13<h1>Note: this is the flat content of the <a href="index.html">web
14site</a></h1>
15
Daniel Veillardc9484202001-10-24 12:35:52 +0000[diff] [blame]16<h1 style="text-align: center">libxml, a.k.a. gnome-xml</h1>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]17
18<p></p>
Daniel Veillard9c466822001-10-25 12:03:39 +0000[diff] [blame]19
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]20<p>Libxml is the XML C library developed for the Gnome project. XML itself
Daniel Veillard9c466822001-10-25 12:03:39 +0000[diff] [blame]21is a metalanguage to design markup languages, i.e. text language where
22semantic and structure are added to the content using extra "markup"
23information enclosed between angle bracket. HTML is the most well-known
Daniel Veillard1eb24242002-03-18 11:33:03 +0000[diff] [blame]24markup language. Though the library is written in C <a href="python.html">a
25variety of language binding</a> makes it available in other environments.</p>
Daniel Veillard9c466822001-10-25 12:03:39 +0000[diff] [blame]26
27<p>Libxml2 implements a number of existing standards related to markup
28languages:</p>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]29<ul>
Daniel Veillard9c466822001-10-25 12:03:39 +0000[diff] [blame]30 <li>the XML standard: <a
31 href="http://www.w3.org/TR/REC-xml">http://www.w3.org/TR/REC-xml</a></li>
32 <li>Namespaces in XML: <a
33 href="http://www.w3.org/TR/REC-xml-names/">http://www.w3.org/TR/REC-xml-names/</a></li>
34 <li>XML Base: <a
35 href="http://www.w3.org/TR/xmlbase/">http://www.w3.org/TR/xmlbase/</a></li>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]36 <li><a href="http://www.cis.ohio-state.edu/rfc/rfc2396.txt">RFC 2396</a> :
37 Uniform Resource Identifiers <a
Daniel Veillard9c466822001-10-25 12:03:39 +0000[diff] [blame]38 href="http://www.ietf.org/rfc/rfc2396.txt">http://www.ietf.org/rfc/rfc2396.txt</a></li>
39 <li>XML Path Language (XPath) 1.0: <a
40 href="http://www.w3.org/TR/xpath">http://www.w3.org/TR/xpath</a></li>
41 <li>HTML4 parser: <a
42 href="http://www.w3.org/TR/html401/">http://www.w3.org/TR/html401/</a></li>
43 <li>most of XML Pointer Language (XPointer) Version 1.0: <a
44 href="http://www.w3.org/TR/xptr">http://www.w3.org/TR/xptr</a></li>
45 <li>XML Inclusions (XInclude) Version 1.0: <a
46 href="http://www.w3.org/TR/xinclude/">http://www.w3.org/TR/xinclude/</a></li>
47 <li>[ISO-8859-1], <a
48 href="http://www.cis.ohio-state.edu/rfc/rfc2044.txt">rfc2044</a> [UTF-8]
49 and <a href="http://www.cis.ohio-state.edu/rfc/rfc2781.txt">rfc2781</a>
50 [UTF-16] core encodings</li>
51 <li>part of SGML Open Technical Resolution TR9401:1997</li>
52 <li>XML Catalogs Working Draft 06 August 2001: <a
53 href="http://www.oasis-open.org/committees/entity/spec-2001-08-06.html">http://www.oasis-open.org/committees/entity/spec-2001-08-06.html</a></li>
Daniel Veillard5c396542002-03-15 07:57:50 +0000[diff] [blame]54 <li>Canonical XML Version 1.0: <a
55 href="http://www.w3.org/TR/xml-c14n">http://www.w3.org/TR/xml-c14n</a>
Daniel Veillard2d347fa2002-03-17 10:34:11 +0000[diff] [blame]56 and the Exclusive XML Canonicalization CR draft <a
57 href="http://www.w3.org/TR/xml-exc-c14n">http://www.w3.org/TR/xml-exc-c14n</a></li>
Daniel Veillard96984452000-08-31 13:50:12 +0000[diff] [blame]58</ul>
59
Daniel Veillard9c466822001-10-25 12:03:39 +0000[diff] [blame]60<p>In most cases libxml tries to implement the specifications in a relatively
Daniel Veillarda5393562002-02-20 11:40:49 +0000[diff] [blame]61strict way. As of release 2.4.16, libxml2 passes all 1800+ tests from the <a
62href="http://www.oasis-open.org/committees/xml-conformance/">OASIS XML Tests
63Suite</a>.</p>
Daniel Veillard5b16f582002-02-20 11:38:46 +0000[diff] [blame]64
65<p>To some extent libxml2 provide some support for the following other
66specification but don't claim to implement them:</p>
Daniel Veillard9c466822001-10-25 12:03:39 +0000[diff] [blame]67<ul>
68 <li>Document Object Model (DOM) <a
69 href="http://www.w3.org/TR/DOM-Level-2-Core/">http://www.w3.org/TR/DOM-Level-2-Core/</a>
70 it doesn't implement the API itself, gdome2 does this in top of
71 libxml2</li>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]72 <li><a href="http://www.cis.ohio-state.edu/rfc/rfc959.txt">RFC 959</a> :
73 libxml implements a basic FTP client code</li>
74 <li><a href="http://www.cis.ohio-state.edu/rfc/rfc1945.txt">RFC 1945</a> :
75 HTTP/1.0, again a basic HTTP client code</li>
Daniel Veillard9c466822001-10-25 12:03:39 +0000[diff] [blame]76 <li>SAX: a minimal SAX implementation compatible with early expat
77 versions</li>
78 <li>DocBook SGML v4: libxml2 includes a hackish parser to transition to
79 XML</li>
80</ul>
81
Daniel Veillarde6d8e202002-05-02 06:11:10 +0000[diff] [blame]82<p>XML Schemas is being worked on but it would be far too early to make any
83conformance statement about it at the moment.</p>
84
Daniel Veillard2d347fa2002-03-17 10:34:11 +0000[diff] [blame]85<p>Libxml2 is known to be very portable, the library should build and work
86without serious troubles on a variety of systems (Linux, Unix, Windows,
87CygWin, MacOs, MacOsX, RISC Os, OS/2, VMS, QNX, MVS, ...)</p>
Daniel Veillard9c466822001-10-25 12:03:39 +0000[diff] [blame]88
Daniel Veillard96984452000-08-31 13:50:12 +0000[diff] [blame]89<p>Separate documents:</p>
90<ul>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]91 <li><a href="http://xmlsoft.org/XSLT/">the libxslt page</a> providing an
Daniel Veillard2d347fa2002-03-17 10:34:11 +0000[diff] [blame]92 implementation of XSLT 1.0 and common extensions like EXSLT for
93 libxml2</li>
Daniel Veillardc6271d22001-10-27 07:50:58 +0000[diff] [blame]94 <li><a href="http://www.cs.unibo.it/~casarini/gdome2/">the gdome2 page</a>
Daniel Veillard2d347fa2002-03-17 10:34:11 +0000[diff] [blame]95 : a standard DOM2 implementation for libxml2</li>
96 <li><a href="http://www.aleksey.com/xmlsec/">the XMLSec page</a>: an
97 implementation of <a href="http://www.w3.org/TR/xmldsig-core/">W3C XML
98 Digital Signature</a> for libxml2</li>
Daniel Veillarde6d8e202002-05-02 06:11:10 +0000[diff] [blame]99 <li>also check the related links section below for more related and active
100 projects.</li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]101</ul>
102
103<h2><a name="Introducti">Introduction</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]104
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]105<p>This document describes libxml, the <a
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]106href="http://www.w3.org/XML/">XML</a> C library developed for the <a
Daniel Veillardec78c0f2000-08-25 10:25:23 +0000[diff] [blame]107href="http://www.gnome.org/">Gnome</a> project. <a
108href="http://www.w3.org/XML/">XML is a standard</a> for building tag-based
109structured documents/data.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]110
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]111<p>Here are some key points about libxml:</p>
112<ul>
Daniel Veillard2d347fa2002-03-17 10:34:11 +0000[diff] [blame]113 <li>Libxml exports Push (progressive) and Pull (blocking) type parser
114 interfaces for both XML and HTML.</li>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]115 <li>Libxml can do DTD validation at parse time, using a parsed document
116 instance, or with an arbitrary DTD.</li>
Daniel Veillard2d347fa2002-03-17 10:34:11 +0000[diff] [blame]117 <li>Libxml includes complete <a
Daniel Veillard8c2ecaf2001-07-10 17:53:07 +0000[diff] [blame]118 href="http://www.w3.org/TR/xpath">XPath</a>, <a
119 href="http://www.w3.org/TR/xptr">XPointer</a> and <a
120 href="http://www.w3.org/TR/xinclude">XInclude</a> implementations.</li>
Daniel Veillardec78c0f2000-08-25 10:25:23 +0000[diff] [blame]121 <li>It is written in plain C, making as few assumptions as possible, and
Daniel Veillard189446d2000-10-13 10:23:06 +0000[diff] [blame]122 sticking closely to ANSI C/POSIX for easy embedding. Works on
Daniel Veillardab8500d2000-10-15 21:06:19 +0000[diff] [blame]123 Linux/Unix/Windows, ported to a number of other platforms.</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]124 <li>Basic support for HTTP and FTP client allowing applications to fetch
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]125 remote resources</li>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]126 <li>The design is modular, most of the extensions can be compiled out.</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]127 <li>The internal document representation is as close as possible to the <a
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]128 href="http://www.w3.org/DOM/">DOM</a> interfaces.</li>
129 <li>Libxml also has a <a href="http://www.megginson.com/SAX/index.html">SAX
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]130 like interface</a>; the interface is designed to be compatible with <a
131 href="http://www.jclark.com/xml/expat.html">Expat</a>.</li>
Daniel Veillardc575b992002-02-08 13:28:40 +0000[diff] [blame]132 <li>This library is released under the <a
133 href="http://www.opensource.org/licenses/mit-license.html">MIT
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]134 License</a> see the Copyright file in the distribution for the precise
Daniel Veillardc575b992002-02-08 13:28:40 +0000[diff] [blame]135 wording.</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]136</ul>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]137
Daniel Veillarde0c1d722001-03-21 10:28:36 +0000[diff] [blame]138<p>Warning: unless you are forced to because your application links with a
Daniel Veillard2d347fa2002-03-17 10:34:11 +0000[diff] [blame]139Gnome-1.X library requiring it, <strong><span
Daniel Veillarde0c1d722001-03-21 10:28:36 +0000[diff] [blame]140style="background-color: #FF0000">Do Not Use libxml1</span></strong>, use
141libxml2</p>
142
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]143<h2><a name="FAQ">FAQ</a></h2>
144
145<p>Table of Content:</p>
146<ul>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]147 <li><a href="FAQ.html#License">License(s)</a></li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]148 <li><a href="FAQ.html#Installati">Installation</a></li>
149 <li><a href="FAQ.html#Compilatio">Compilation</a></li>
150 <li><a href="FAQ.html#Developer">Developer corner</a></li>
151</ul>
152
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]153<h3><a name="License">License</a>(s)</h3>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]154<ol>
155 <li><em>Licensing Terms for libxml</em>
Daniel Veillardc575b992002-02-08 13:28:40 +0000[diff] [blame]156 <p>libxml is released under the <a
157 href="http://www.opensource.org/licenses/mit-license.html">MIT
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]158 License</a>, see the file Copyright in the distribution for the precise
Daniel Veillardc575b992002-02-08 13:28:40 +0000[diff] [blame]159 wording</p>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]160 </li>
161 <li><em>Can I embed libxml in a proprietary application ?</em>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]162 <p>Yes. The MIT License allows you to also keep proprietary the changes
Daniel Veillardc0801af2002-05-28 16:28:42 +0000[diff] [blame]163 you made to libxml, but it would be graceful to provide back bug fixes
164 and improvements as patches for possible incorporation in the main
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]165 development tree</p>
166 </li>
167</ol>
168
169<h3><a name="Installati">Installation</a></h3>
170<ol>
171 <li>Unless you are forced to because your application links with a Gnome
172 library requiring it, <strong><span style="background-color: #FF0000">Do
173 Not Use libxml1</span></strong>, use libxml2</li>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]174 <li><em>Where can I get libxml</em> ?
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]175 <p>The original distribution comes from <a
176 href="ftp://rpmfind.net/pub/libxml/">rpmfind.net</a> or <a
177 href="ftp://ftp.gnome.org/pub/GNOME/stable/sources/libxml/">gnome.org</a></p>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]178 <p>Most Linux and BSD distributions include libxml, this is probably the
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]179 safer way for end-users</p>
180 <p>David Doolin provides precompiled Windows versions at <a
181 href="http://www.ce.berkeley.edu/~doolin/code/libxmlwin32/ ">http://www.ce.berkeley.edu/~doolin/code/libxmlwin32/</a></p>
182 </li>
183 <li><em>I see libxml and libxml2 releases, which one should I install ?</em>
184 <ul>
185 <li>If you are not concerned by any existing backward compatibility
186 with existing application, install libxml2 only</li>
187 <li>If you are not doing development, you can safely install both.
188 usually the packages <a
189 href="http://rpmfind.net/linux/RPM/libxml.html">libxml</a> and <a
190 href="http://rpmfind.net/linux/RPM/libxml2.html">libxml2</a> are
191 compatible (this is not the case for development packages)</li>
192 <li>If you are a developer and your system provides separate packaging
193 for shared libraries and the development components, it is possible
194 to install libxml and libxml2, and also <a
195 href="http://rpmfind.net/linux/RPM/libxml-devel.html">libxml-devel</a>
196 and <a
197 href="http://rpmfind.net/linux/RPM/libxml2-devel.html">libxml2-devel</a>
198 too for libxml2 &gt;= 2.3.0</li>
199 <li>If you are developing a new application, please develop against
200 libxml2(-devel)</li>
201 </ul>
202 </li>
203 <li><em>I can't install the libxml package it conflicts with libxml0</em>
204 <p>You probably have an old libxml0 package used to provide the shared
205 library for libxml.so.0, you can probably safely remove it. Anyway the
206 libxml packages provided on <a
207 href="ftp://rpmfind.net/pub/libxml/">rpmfind.net</a> provides
208 libxml.so.0</p>
209 </li>
210 <li><em>I can't install the libxml(2) RPM package due to failed
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]211 dependencies</em>
212 <p>The most generic solution is to re-fetch the latest src.rpm , and
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]213 rebuild it locally with</p>
214 <p><code>rpm --rebuild libxml(2)-xxx.src.rpm</code></p>
215 <p>if everything goes well it will generate two binary rpm (one providing
216 the shared libs and xmllint, and the other one, the -devel package
217 providing includes, static libraries and scripts needed to build
218 applications with libxml(2)) that you can install locally.</p>
219 </li>
220</ol>
221
222<h3><a name="Compilatio">Compilation</a></h3>
223<ol>
224 <li><em>What is the process to compile libxml ?</em>
225 <p>As most UNIX libraries libxml follows the "standard":</p>
226 <p><code>gunzip -c xxx.tar.gz | tar xvf -</code></p>
227 <p><code>cd libxml-xxxx</code></p>
228 <p><code>./configure --help</code></p>
229 <p>to see the options, then the compilation/installation proper</p>
230 <p><code>./configure [possible options]</code></p>
231 <p><code>make</code></p>
232 <p><code>make install</code></p>
233 <p>At that point you may have to rerun ldconfig or similar utility to
234 update your list of installed shared libs.</p>
235 </li>
236 <li><em>What other libraries are needed to compile/install libxml ?</em>
237 <p>Libxml does not requires any other library, the normal C ANSI API
238 should be sufficient (please report any violation to this rule you may
239 find).</p>
240 <p>However if found at configuration time libxml will detect and use the
241 following libs:</p>
242 <ul>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]243 <li><a href="http://www.info-zip.org/pub/infozip/zlib/">libz</a> : a
244 highly portable and available widely compression library</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]245 <li>iconv: a powerful character encoding conversion library. It's
246 included by default on recent glibc libraries, so it doesn't need to
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]247 be installed specifically on Linux. It seems it's now <a
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]248 href="http://www.opennc.org/onlinepubs/7908799/xsh/iconv.html">part
249 of the official UNIX</a> specification. Here is one <a
250 href="http://clisp.cons.org/~haible/packages-libiconv.html">implementation
251 of the library</a> which source can be found <a
252 href="ftp://ftp.ilog.fr/pub/Users/haible/gnu/">here</a>.</li>
253 </ul>
254 </li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]255 <li><em>make check fails on some platforms</em>
256 <p>Sometime the regression tests results don't completely match the value
257 produced by the parser, and the makefile uses diff to print the delta. On
258 some platforms the diff return breaks the compilation process, if the
Daniel Veillarde46182c2002-02-12 14:29:11 +0000[diff] [blame]259 diff is small this is probably not a serious problem.</p>
260 <p>Sometimes (especially on Solaris) make checks fails due to limitations
261 in make. Try using GNU-make instead.</p>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]262 </li>
263 <li><em>I use the CVS version and there is no configure script</em>
264 <p>The configure (and other Makefiles) are generated. Use the autogen.sh
265 script to regenerate the configure and Makefiles, like:</p>
266 <p><code>./autogen.sh --prefix=/usr --disable-shared</code></p>
267 </li>
268 <li><em>I have troubles when running make tests with gcc-3.0</em>
269 <p>It seems the initial release of gcc-3.0 has a problem with the
270 optimizer which miscompiles the URI module. Please use another
271 compiler</p>
272 </li>
273</ol>
274
275<h3><a name="Developer">Developer</a> corner</h3>
276<ol>
277 <li><em>xmlDocDump() generates output on one line</em>
278 <p>libxml will not <strong>invent</strong> spaces in the content of a
279 document since <strong>all spaces in the content of a document are
280 significant</strong>. If you build a tree from the API and want
281 indentation:</p>
282 <ol>
283 <li>the correct way is to generate those yourself too</li>
284 <li>the dangerous way is to ask libxml to add those blanks to your
285 content <strong>modifying the content of your document in the
286 process</strong>. The result may not be what you expect. There is
287 <strong>NO</strong> way to guarantee that such a modification won't
288 impact other part of the content of your document. See <a
289 href="http://xmlsoft.org/html/libxml-parser.html#XMLKEEPBLANKSDEFAULT">xmlKeepBlanksDefault
290 ()</a> and <a
291 href="http://xmlsoft.org/html/libxml-tree.html#XMLSAVEFORMATFILE">xmlSaveFormatFile
292 ()</a></li>
293 </ol>
294 </li>
295 <li>Extra nodes in the document:
296 <p><em>For a XML file as below:</em></p>
297 <pre>&lt;?xml version="1.0"?&gt;
298&lt;PLAN xmlns="http://www.argus.ca/autotest/1.0/"&gt;
299&lt;NODE CommFlag="0"/&gt;
300&lt;NODE CommFlag="1"/&gt;
301&lt;/PLAN&gt;</pre>
302 <p><em>after parsing it with the function
303 pxmlDoc=xmlParseFile(...);</em></p>
304 <p><em>I want to the get the content of the first node (node with the
305 CommFlag="0")</em></p>
306 <p><em>so I did it as following;</em></p>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]307 <pre>xmlNodePtr pnode;
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]308pnode=pxmlDoc-&gt;children-&gt;children;</pre>
309 <p><em>but it does not work. If I change it to</em></p>
310 <pre>pnode=pxmlDoc-&gt;children-&gt;children-&gt;next;</pre>
311 <p><em>then it works. Can someone explain it to me.</em></p>
312 <p></p>
313 <p>In XML all characters in the content of the document are significant
314 <strong>including blanks and formatting line breaks</strong>.</p>
315 <p>The extra nodes you are wondering about are just that, text nodes with
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]316 the formatting spaces which are part of the document but that people tend
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]317 to forget. There is a function <a
318 href="http://xmlsoft.org/html/libxml-parser.html">xmlKeepBlanksDefault
319 ()</a> to remove those at parse time, but that's an heuristic, and its
320 use should be limited to case where you are sure there is no
321 mixed-content in the document.</p>
322 </li>
323 <li><em>I get compilation errors of existing code like when accessing
324 <strong>root</strong> or <strong>childs fields</strong> of nodes</em>
325 <p>You are compiling code developed for libxml version 1 and using a
326 libxml2 development environment. Either switch back to libxml v1 devel or
327 even better fix the code to compile with libxml2 (or both) by <a
328 href="upgrade.html">following the instructions</a>.</p>
329 </li>
330 <li><em>I get compilation errors about non existing
331 <strong>xmlRootNode</strong> or <strong>xmlChildrenNode</strong>
332 fields</em>
333 <p>The source code you are using has been <a
334 href="upgrade.html">upgraded</a> to be able to compile with both libxml
335 and libxml2, but you need to install a more recent version:
336 libxml(-devel) &gt;= 1.8.8 or libxml2(-devel) &gt;= 2.1.0</p>
337 </li>
338 <li><em>XPath implementation looks seriously broken</em>
339 <p>XPath implementation prior to 2.3.0 was really incomplete, upgrade to
Daniel Veillard2d347fa2002-03-17 10:34:11 +0000[diff] [blame]340 a recent version, there is no known bug in the current version.</p>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]341 </li>
342 <li><em>The example provided in the web page does not compile</em>
343 <p>It's hard to maintain the documentation in sync with the code
344 &lt;grin/&gt; ...</p>
345 <p>Check the previous points 1/ and 2/ raised before, and send
346 patches.</p>
347 </li>
348 <li><em>Where can I get more examples and informations than in the web
349 page</em>
350 <p>Ideally a libxml book would be nice. I have no such plan ... But you
351 can:</p>
352 <ul>
353 <li>check more deeply the <a href="html/libxml-lib.html">existing
354 generated doc</a></li>
355 <li>looks for examples of use for libxml function using the Gnome code
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]356 for example the following will query the full Gnome CVS base for the
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]357 use of the <strong>xmlAddChild()</strong> function:
358 <p><a
359 href="http://cvs.gnome.org/lxr/search?string=xmlAddChild">http://cvs.gnome.org/lxr/search?string=xmlAddChild</a></p>
360 <p>This may be slow, a large hardware donation to the gnome project
361 could cure this :-)</p>
362 </li>
363 <li><a
364 href="http://cvs.gnome.org/bonsai/rview.cgi?cvsroot=/cvs/gnome&amp;dir=gnome-xml">Browse
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]365 the libxml source</a> , I try to write code as clean and documented
Daniel Veillard2d347fa2002-03-17 10:34:11 +0000[diff] [blame]366 as possible, so looking at it may be helpful. Especially the code of
367 xmllint.c and of the various testXXX.c tests programs should provide
368 good example on how to do things with the library.</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]369 </ul>
370 </li>
371 <li>What about C++ ?
372 <p>libxml is written in pure C in order to allow easy reuse on a number
373 of platforms, including embedded systems. I don't intend to convert to
374 C++.</p>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]375 <p>There is however a few C++ wrappers which may fulfill your needs:</p>
Daniel Veillard9b6fd302002-05-13 12:06:47 +0000[diff] [blame]376 <ul>
377 <li>by Ari Johnson &lt;ari@btigate.com&gt;:
378 <p>Website: <a
379 href="http://lusis.org/~ari/xml++/">http://lusis.org/~ari/xml++/</a></p>
380 <p>Download: <a
381 href="http://lusis.org/~ari/xml++/libxml++.tar.gz">http://lusis.org/~ari/xml++/libxml++.tar.gz</a></p>
382 </li>
383 <li>by Peter Jones &lt;pjones@pmade.org&gt;
384 <p>Website: <a
385 href="http://pmade.org/pjones/software/xmlwrapp/">http://pmade.org/pjones/software/xmlwrapp/</a></p>
386 </li>
387 </ul>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]388 </li>
389 <li>How to validate a document a posteriori ?
390 <p>It is possible to validate documents which had not been validated at
391 initial parsing time or documents who have been built from scratch using
392 the API. Use the <a
393 href="http://xmlsoft.org/html/libxml-valid.html#XMLVALIDATEDTD">xmlValidateDtd()</a>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]394 function. It is also possible to simply add a DTD to an existing
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]395 document:</p>
396 <pre>xmlDocPtr doc; /* your existing document */
397 xmlDtdPtr dtd = xmlParseDTD(NULL, filename_of_dtd); /* parse the DTD */
398 dtd-&gt;name = xmlStrDup((xmlChar*)"root_name"); /* use the given root */
399
400 doc-&gt;intSubset = dtd;
401 if (doc-&gt;children == NULL) xmlAddChild((xmlNodePtr)doc, (xmlNodePtr)dtd);
402 else xmlAddPrevSibling(doc-&gt;children, (xmlNodePtr)dtd);
403 </pre>
404 </li>
405 <li>etc ...</li>
406</ol>
407
408<p></p>
409
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]410<h2><a name="Documentat">Documentation</a></h2>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]411
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]412<p>There are some on-line resources about using libxml:</p>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]413<ol>
Daniel Veillard365e13b2000-07-02 07:56:37 +0000[diff] [blame]414 <li>Check the <a href="FAQ.html">FAQ</a></li>
Daniel Veillardc19fccc2000-07-03 11:52:01 +0000[diff] [blame]415 <li>Check the <a href="http://xmlsoft.org/html/libxml-lib.html">extensive
Daniel Veillard8c6d6af2000-08-25 17:14:13 +0000[diff] [blame]416 documentation</a> automatically extracted from code comments (using <a
417 href="http://cvs.gnome.org/bonsai/rview.cgi?cvsroot=/cvs/gnome&amp;dir=gtk-doc">gtk
418 doc</a>).</li>
Daniel Veillard8d869642000-07-14 12:12:59 +0000[diff] [blame]419 <li>Look at the documentation about <a href="encoding.html">libxml
420 internationalization support</a></li>
Daniel Veillardbc66f852002-01-14 09:49:20 +0000[diff] [blame]421 <li>This page provides a global overview and <a href="example.html">some
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]422 examples</a> on how to use libxml.</li>
MDT 2002 John Fleckd7ca7f92002-06-13 03:41:03 +0000[diff] [blame]423 <li>John Fleck's <a href="tutorial/index.html">libxml tutorial</a></li>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]424 <li><a href="mailto:james@daa.com.au">James Henstridge</a> wrote <a
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]425 href="http://www.daa.com.au/~james/gnome/xml-sax/xml-sax.html">some nice
426 documentation</a> explaining how to use the libxml SAX interface.</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]427 <li>George Lebl wrote <a
428 href="http://www-4.ibm.com/software/developer/library/gnome3/">an article
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]429 for IBM developerWorks</a> about using libxml.</li>
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]430 <li>Check <a href="http://cvs.gnome.org/lxr/source/gnome-xml/TODO">the TODO
431 file</a></li>
432 <li>Read the <a href="upgrade.html">1.x to 2.x upgrade path</a>. If you are
433 starting a new project using libxml you should really use the 2.x
434 version.</li>
Daniel Veillard845cce42002-01-09 11:51:37 +0000[diff] [blame]435 <li>And don't forget to look at the <a
436 href="http://mail.gnome.org/archives/xml/">mailing-list archive</a>.</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]437</ol>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]438
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]439<h2><a name="Reporting">Reporting bugs and getting help</a></h2>
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000[diff] [blame]440
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]441<p>Well, bugs or missing features are always possible, and I will make a
442point of fixing them in a timely fashion. The best way to report a bug is to
443use the <a href="http://bugzilla.gnome.org/buglist.cgi?product=libxml">Gnome
444bug tracking database</a> (make sure to use the "libxml" module name). I look
445at reports there regularly and it's good to have a reminder when a bug is
Daniel Veillard51095312001-10-28 18:51:57 +0000[diff] [blame]446still open. Be sure to specify that the bug is for the package libxml.</p>
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000[diff] [blame]447
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]448<p>There is also a mailing-list <a
Daniel Veillard3197f162001-04-04 00:40:08 +0000[diff] [blame]449href="mailto:xml@gnome.org">xml@gnome.org</a> for libxml, with an <a
450href="http://mail.gnome.org/archives/xml/">on-line archive</a> (<a
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]451href="http://xmlsoft.org/messages">old</a>). To subscribe to this list,
452please visit the <a
453href="http://mail.gnome.org/mailman/listinfo/xml">associated Web</a> page and
454follow the instructions. <strong>Do not send code, I won't debug it</strong>
455(but patches are really appreciated!).</p>
Daniel Veillard234547b2001-07-05 09:46:10 +0000[diff] [blame]456
Daniel Veillard008186f2001-09-13 14:24:44 +0000[diff] [blame]457<p>Check the following <strong><span style="color: #FF0000">before
458posting</span></strong>:</p>
Daniel Veillard234547b2001-07-05 09:46:10 +0000[diff] [blame]459<ul>
Daniel Veillarddadd0872001-09-15 09:21:44 +0000[diff] [blame]460 <li>read the <a href="FAQ.html">FAQ</a></li>
Daniel Veillard234547b2001-07-05 09:46:10 +0000[diff] [blame]461 <li>make sure you are <a href="ftp://xmlsoft.org/">using a recent
462 version</a>, and that the problem still shows up in those</li>
463 <li>check the <a href="http://mail.gnome.org/archives/xml/">list
464 archives</a> to see if the problem was reported already, in this case
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]465 there is probably a fix available, similarly check the <a
Daniel Veillarde7ead2d2001-08-22 23:44:09 +0000[diff] [blame]466 href="http://bugzilla.gnome.org/buglist.cgi?product=libxml">registered
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]467 open bugs</a></li>
Daniel Veillard234547b2001-07-05 09:46:10 +0000[diff] [blame]468 <li>make sure you can reproduce the bug with xmllint or one of the test
469 programs found in source in the distribution</li>
470 <li>Please send the command showing the error as well as the input (as an
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]471 attachment)</li>
Daniel Veillard234547b2001-07-05 09:46:10 +0000[diff] [blame]472</ul>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]473
Daniel Veillarddadd0872001-09-15 09:21:44 +0000[diff] [blame]474<p>Then send the bug with associated informations to reproduce it to the <a
Daniel Veillard33a67802001-03-07 09:44:02 +0000[diff] [blame]475href="mailto:xml@gnome.org">xml@gnome.org</a> list; if it's really libxml
Daniel Veillard008186f2001-09-13 14:24:44 +0000[diff] [blame]476related I will approve it.. Please do not send me mail directly, it makes
477things really harder to track and in some cases I'm not the best person to
478answer a given question, ask the list instead.</p>
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000[diff] [blame]479
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]480<p>Of course, bugs reported with a suggested patch for fixing them will
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]481probably be processed faster.</p>
482
483<p>If you're looking for help, a quick look at <a
Daniel Veillardf7ed3362001-08-17 12:01:21 +0000[diff] [blame]484href="http://mail.gnome.org/archives/xml/">the list archive</a> may actually
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]485provide the answer, I usually send source samples when answering libxml usage
Daniel Veillard6f0adb52000-07-03 11:41:26 +0000[diff] [blame]486questions. The <a href="http://xmlsoft.org/html/book1.html">auto-generated
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]487documentation</a> is not as polished as I would like (i need to learn more
488about DocBook), but it's a good starting point.</p>
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]489
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]490<h2><a name="help">How to help</a></h2>
491
492<p>You can help the project in various ways, the best thing to do first is to
493subscribe to the mailing-list as explained before, check the <a
Daniel Veillardf7ed3362001-08-17 12:01:21 +0000[diff] [blame]494href="http://mail.gnome.org/archives/xml/">archives </a>and the <a
495href="http://bugzilla.gnome.org/buglist.cgi?product=libxml">Gnome bug
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]496database:</a>:</p>
497<ol>
498 <li>provide patches when you find problems</li>
Daniel Veillard189446d2000-10-13 10:23:06 +0000[diff] [blame]499 <li>provide the diffs when you port libxml to a new platform. They may not
Daniel Veillardab8500d2000-10-15 21:06:19 +0000[diff] [blame]500 be integrated in all cases but help pinpointing portability problems
501 and</li>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]502 <li>provide documentation fixes (either as patches to the code comments or
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]503 as HTML diffs).</li>
504 <li>provide new documentations pieces (translations, examples, etc ...)</li>
505 <li>Check the TODO file and try to close one of the items</li>
506 <li>take one of the points raised in the archive or the bug database and
Daniel Veillarde7ead2d2001-08-22 23:44:09 +0000[diff] [blame]507 provide a fix. <a href="mailto:daniel@veillard.com">Get in touch with me
508 </a>before to avoid synchronization problems and check that the suggested
509 fix will fit in nicely :-)</li>
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]510</ol>
511
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]512<h2><a name="Downloads">Downloads</a></h2>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]513
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]514<p>The latest versions of libxml can be found on <a
Daniel Veillard20c8cf22001-06-26 22:47:36 +0000[diff] [blame]515href="ftp://xmlsoft.org/">xmlsoft.org</a> (<a
516href="ftp://speakeasy.rpmfind.net/pub/libxml/">Seattle</a>, <a
517href="ftp://fr.rpmfind.net/pub/libxml/">France</a>) or on the <a
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]518href="ftp://ftp.gnome.org/pub/GNOME/MIRRORS.html">Gnome FTP server</a> either
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]519as a <a href="ftp://ftp.gnome.org/pub/GNOME/stable/sources/libxml/">source
Daniel Veillard306be992000-07-03 12:38:45 +0000[diff] [blame]520archive</a> or <a
Daniel Veillarda41123c2001-04-22 19:31:20 +0000[diff] [blame]521href="ftp://ftp.gnome.org/pub/GNOME/stable/redhat/i386/libxml/">RPM
Daniel Veillard0bfbb422002-04-26 09:21:45 +0000[diff] [blame]522packages</a>, Antonin Sprinzl also provide <a
523href="ftp://gd.tuwien.ac.at/pub/libxml/">a mirror in Austria</a>. (NOTE that
524you need both the <a
Daniel Veillardc19fccc2000-07-03 11:52:01 +0000[diff] [blame]525href="http://rpmfind.net/linux/RPM/libxml2.html">libxml(2)</a> and <a
526href="http://rpmfind.net/linux/RPM/libxml2-devel.html">libxml(2)-devel</a>
Daniel Veillard95189532001-07-26 18:30:26 +0000[diff] [blame]527packages installed to compile applications using libxml.) <a
Daniel Veillardb2fb8ed2002-04-01 09:33:12 +0000[diff] [blame]528href="mailto:igor@stud.fh-frankfurt.de">Igor Zlatkovic</a> is now the
529maintainer of the Windows port, <a
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]530href="http://www.fh-frankfurt.de/~igor/projects/libxml/index.html">he
Daniel Veillardc6271d22001-10-27 07:50:58 +0000[diff] [blame]531provides binaries</a>. <a href="mailto:Gary.Pennington@sun.com">Gary
Daniel Veillard1aadc442001-11-28 13:10:32 +0000[diff] [blame]532Pennington</a> provides <a href="http://garypennington.net/libxml2/">Solaris
533binaries</a>.</p>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]534
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]535<p><a name="Snapshot">Snapshot:</a></p>
536<ul>
537 <li>Code from the W3C cvs base libxml <a
Daniel Veillard33a67802001-03-07 09:44:02 +0000[diff] [blame]538 href="ftp://xmlsoft.org/cvs-snapshot.tar.gz">cvs-snapshot.tar.gz</a></li>
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]539 <li>Docs, content of the web site, the list archive included <a
Daniel Veillard33a67802001-03-07 09:44:02 +0000[diff] [blame]540 href="ftp://xmlsoft.org/libxml-docs.tar.gz">libxml-docs.tar.gz</a></li>
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]541</ul>
542
Daniel Veillardc6271d22001-10-27 07:50:58 +0000[diff] [blame]543<p><a name="Contribs">Contributions:</a></p>
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]544
545<p>I do accept external contributions, especially if compiling on another
Daniel Veillardc6271d22001-10-27 07:50:58 +0000[diff] [blame]546platform, get in touch with me to upload the package, wrappers for various
Daniel Veillard51095312001-10-28 18:51:57 +0000[diff] [blame]547languages have been provided, and can be found in the <a
548href="contribs.html">contrib section</a></p>
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]549
Daniel Veillard82687162001-01-22 15:32:01 +0000[diff] [blame]550<p>Libxml is also available from CVS:</p>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]551<ul>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]552 <li><p>The <a
553 href="http://cvs.gnome.org/bonsai/rview.cgi?cvsroot=/cvs/gnome&amp;dir=gnome-xml">Gnome
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]554 CVS base</a>. Check the <a
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]555 href="http://developer.gnome.org/tools/cvs.html">Gnome CVS Tools</a>
556 page; the CVS module is <b>gnome-xml</b>.</p>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]557 </li>
Daniel Veillard82687162001-01-22 15:32:01 +0000[diff] [blame]558 <li>The <strong>libxslt</strong> module is also present there</li>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]559</ul>
560
561<h2><a name="News">News</a></h2>
562
Daniel Veillard944b5ff1999-12-15 19:08:24 +0000[diff] [blame]563<h3>CVS only : check the <a
564href="http://cvs.gnome.org/lxr/source/gnome-xml/ChangeLog">Changelog</a> file
Daniel Veillard189446d2000-10-13 10:23:06 +0000[diff] [blame]565for a really accurate description</h3>
Daniel Veillardab8500d2000-10-15 21:06:19 +0000[diff] [blame]566
Daniel Veillarde6d8e202002-05-02 06:11:10 +0000[diff] [blame]567<p>Items not finished and worked on, get in touch with the list if you want
568to test those</p>
Daniel Veillardab8500d2000-10-15 21:06:19 +0000[diff] [blame]569<ul>
Daniel Veillardcf27f7c2002-04-30 07:12:39 +0000[diff] [blame]570 <li>Finishing up <a href="http://www.w3.org/TR/xmlschema-1/">XML
571 Schemas</a> and <a href="http://www.w3.org/TR/xinclude">XInclude</a></li>
572</ul>
573
Daniel Veillardc0801af2002-05-28 16:28:42 +0000[diff] [blame]574<h3>2.4.22: May 27 2002</h3>
575<ul>
576 <li>a number of bug fixes: configure scripts, base handling, parser, memory
577 usage, HTML parser, XPath, documentation (Christian Cornelssen),
578 indentation, URI parsing </li>
579 <li>Optimizations for XMLSec, fixing and making public some of the network
580 protocol handlers (Aleksey)</li>
581 <li>performance patch from Gary Pennington</li>
582 <li>Charles Bozeman provided date and time support for XML Schemas
583 datatypes</li>
584</ul>
585
Daniel Veillardcf27f7c2002-04-30 07:12:39 +0000[diff] [blame]586<h3>2.4.21: Apr 29 2002</h3>
587
588<p>This release is both a bug fix release and also contains the early XML
589Schemas <a href="http://www.w3.org/TR/xmlschema-1/">structures</a> and <a
590href="http://www.w3.org/TR/xmlschema-2/">datatypes</a> code, beware, all
591interfaces are likely to change, there is huge holes, it is clearly a work in
592progress and don't even think of putting this code in a production system,
Daniel Veillarde6d8e202002-05-02 06:11:10 +0000[diff] [blame]593it's actually not compiled in by default. The real fixes are:</p>
Daniel Veillardcf27f7c2002-04-30 07:12:39 +0000[diff] [blame]594<ul>
595 <li>a couple of bugs or limitations introduced in 2.4.20</li>
596 <li>patches for Borland C++ and MSC by Igor</li>
597 <li>some fixes on XPath strings and conformance patches by Richard
598 Jinks</li>
599 <li>patch from Aleksey for the ExcC14N specification</li>
600 <li>OSF/1 bug fix by Bjorn</li>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]601</ul>
602
Daniel Veillarda7084cd2002-04-15 17:12:47 +0000[diff] [blame]603<h3>2.4.20: Apr 15 2002</h3>
604<ul>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]605 <li>bug fixes: file descriptor leak, XPath, HTML output, DTD validation</li>
Daniel Veillarda7084cd2002-04-15 17:12:47 +0000[diff] [blame]606 <li>XPath conformance testing by Richard Jinks</li>
607 <li>Portability fixes: Solaris, MPE/iX, Windows, OSF/1, python bindings,
608 libxml.m4</li>
609</ul>
610
Daniel Veillard19274092002-03-25 16:48:03 +0000[diff] [blame]611<h3>2.4.19: Mar 25 2002</h3>
612<ul>
613 <li>bug fixes: half a dozen XPath bugs, Validation, ISO-Latin to UTF8
614 encoder</li>
615 <li>portability fixes in the HTTP code</li>
Daniel Veillardb2fb8ed2002-04-01 09:33:12 +0000[diff] [blame]616 <li>memory allocation checks using valgrind, and profiling tests</li>
Daniel Veillard19274092002-03-25 16:48:03 +0000[diff] [blame]617 <li>revamp of the Windows build and Makefiles</li>
618</ul>
619
Daniel Veillard34ce8be2002-03-18 19:37:11 +0000[diff] [blame]620<h3>2.4.18: Mar 18 2002</h3>
621<ul>
622 <li>bug fixes: tree, SAX, canonicalization, validation, portability,
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]623 XPath</li>
Daniel Veillard34ce8be2002-03-18 19:37:11 +0000[diff] [blame]624 <li>removed the --with-buffer option it was becoming unmaintainable</li>
625 <li>serious cleanup of the Python makefiles</li>
626 <li>speedup patch to XPath very effective for DocBook stylesheets</li>
627 <li>Fixes for Windows build, cleanup of the documentation</li>
628</ul>
629
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]630<h3>2.4.17: Mar 8 2002</h3>
631<ul>
632 <li>a lot of bug fixes, including "namespace nodes have no parents in
633 XPath"</li>
634 <li>fixed/improved the Python wrappers, added more examples and more
635 regression tests, XPath extension functions can now return node-sets</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]636 <li>added the XML Canonicalization support from Aleksey Sanin</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]637</ul>
638
Daniel Veillard5f4b5992002-02-20 10:22:49 +0000[diff] [blame]639<h3>2.4.16: Feb 20 2002</h3>
640<ul>
641 <li>a lot of bug fixes, most of them were triggered by the XML Testsuite
642 from OASIS and W3C. Compliance has been significantly improved.</li>
643 <li>a couple of portability fixes too.</li>
644</ul>
645
Daniel Veillard397ff112002-02-11 18:27:20 +0000[diff] [blame]646<h3>2.4.15: Feb 11 2002</h3>
647<ul>
648 <li>Fixed the Makefiles, especially the python module ones</li>
649 <li>A few bug fixes and cleanup</li>
650 <li>Includes cleanup</li>
651</ul>
652
Daniel Veillardb6c1e2f2002-02-08 14:52:52 +0000[diff] [blame]653<h3>2.4.14: Feb 8 2002</h3>
654<ul>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]655 <li>Change of License to the <a
Daniel Veillardb6c1e2f2002-02-08 14:52:52 +0000[diff] [blame]656 href="http://www.opensource.org/licenses/mit-license.html">MIT
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]657 License</a> basically for integration in XFree86 codebase, and removing
658 confusion around the previous dual-licensing</li>
Daniel Veillardb6c1e2f2002-02-08 14:52:52 +0000[diff] [blame]659 <li>added Python bindings, beta software but should already be quite
660 complete</li>
661 <li>a large number of fixes and cleanups, especially for all tree
662 manipulations</li>
663 <li>cleanup of the headers, generation of a reference API definition in
664 XML</li>
665</ul>
666
667<h3>2.4.13: Jan 14 2002</h3>
Daniel Veillard744683d2002-01-14 17:30:20 +0000[diff] [blame]668<ul>
669 <li>update of the documentation: John Fleck and Charlie Bozeman</li>
670 <li>cleanup of timing code from Justin Fletcher</li>
671 <li>fixes for Windows and initial thread support on Win32: Igor and Serguei
672 Narojnyi</li>
673 <li>Cygwin patch from Robert Collins</li>
674 <li>added xmlSetEntityReferenceFunc() for Keith Isdale work on xsldbg</li>
675</ul>
676
Daniel Veillardef90ba72001-12-07 14:24:22 +0000[diff] [blame]677<h3>2.4.12: Dec 7 2001</h3>
678<ul>
679 <li>a few bug fixes: thread (Gary Pennington), xmllint (Geert Kloosterman),
680 XML parser (Robin Berjon), XPointer (Danny Jamshy), I/O cleanups
681 (robert)</li>
682 <li>Eric Lavigne contributed project files for MacOS</li>
683 <li>some makefiles cleanups</li>
684</ul>
685
Daniel Veillarda4871052001-11-26 13:19:48 +0000[diff] [blame]686<h3>2.4.11: Nov 26 2001</h3>
687<ul>
688 <li>fixed a couple of errors in the includes, fixed a few bugs, some code
689 cleanups</li>
690 <li>xmllint man pages improvement by Heiko Rupp</li>
691 <li>updated VMS build instructions from John A Fotheringham</li>
692 <li>Windows Makefiles updates from Igor</li>
693</ul>
694
Daniel Veillard43d3f612001-11-10 11:57:23 +0000[diff] [blame]695<h3>2.4.10: Nov 10 2001</h3>
696<ul>
697 <li>URI escaping fix (Joel Young)</li>
698 <li>added xmlGetNodePath() (for paths or XPointers generation)</li>
699 <li>Fixes namespace handling problems when using DTD and validation</li>
700 <li>improvements on xmllint: Morus Walter patches for --format and
701 --encode, Stefan Kost and Heiko Rupp improvements on the --shell</li>
702 <li>fixes for xmlcatalog linking pointed by Weiqi Gao</li>
703 <li>fixes to the HTML parser</li>
704</ul>
705
706<h3>2.4.9: Nov 6 2001</h3>
707<ul>
708 <li>fixes more catalog bugs</li>
709 <li>avoid a compilation problem, improve xmlGetLineNo()</li>
710</ul>
711
Daniel Veillarded421aa2001-11-04 21:22:45 +0000[diff] [blame]712<h3>2.4.8: Nov 4 2001</h3>
713<ul>
714 <li>fixed SGML catalogs broken in previous release, updated xmlcatalog
715 tool</li>
716 <li>fixed a compile errors and some includes troubles.</li>
717</ul>
718
Daniel Veillard52dcab32001-10-30 12:51:17 +0000[diff] [blame]719<h3>2.4.7: Oct 30 2001</h3>
720<ul>
721 <li>exported some debugging interfaces</li>
722 <li>serious rewrite of the catalog code</li>
723 <li>integrated Gary Pennington thread safety patch, added configure option
724 and regression tests</li>
725 <li>removed an HTML parser bug</li>
726 <li>fixed a couple of potentially serious validation bugs</li>
727 <li>integrated the SGML DocBook support in xmllint</li>
728 <li>changed the nanoftp anonymous login passwd</li>
729 <li>some I/O cleanup and a couple of interfaces for Perl wrapper</li>
730 <li>general bug fixes</li>
731 <li>updated xmllint man page by John Fleck</li>
732 <li>some VMS and Windows updates</li>
733</ul>
734
Daniel Veillard60087f32001-10-10 09:45:09 +0000[diff] [blame]735<h3>2.4.6: Oct 10 2001</h3>
736<ul>
Daniel Veillard52dcab32001-10-30 12:51:17 +0000[diff] [blame]737 <li>added an updated man pages by John Fleck</li>
Daniel Veillard60087f32001-10-10 09:45:09 +0000[diff] [blame]738 <li>portability and configure fixes</li>
739 <li>an infinite loop on the HTML parser was removed (William)</li>
740 <li>Windows makefile patches from Igor</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]741 <li>fixed half a dozen bugs reported for libxml or libxslt</li>
Daniel Veillard60087f32001-10-10 09:45:09 +0000[diff] [blame]742 <li>updated xmlcatalog to be able to modify SGML super catalogs</li>
743</ul>
744
Daniel Veillarddadd0872001-09-15 09:21:44 +0000[diff] [blame]745<h3>2.4.5: Sep 14 2001</h3>
746<ul>
747 <li>Remove a few annoying bugs in 2.4.4</li>
748 <li>forces the HTML serializer to output decimal charrefs since some
749 version of Netscape can't handle hexadecimal ones</li>
750</ul>
751
752<h3>1.8.16: Sep 14 2001</h3>
753<ul>
754 <li>maintenance release of the old libxml1 branch, couple of bug and
755 portability fixes</li>
756</ul>
757
Daniel Veillard04382ae2001-09-12 18:51:30 +0000[diff] [blame]758<h3>2.4.4: Sep 12 2001</h3>
759<ul>
760 <li>added --convert to xmlcatalog, bug fixes and cleanups of XML
761 Catalog</li>
762 <li>a few bug fixes and some portability changes</li>
763 <li>some documentation cleanups</li>
764</ul>
765
Daniel Veillard39936902001-08-24 00:49:01 +0000[diff] [blame]766<h3>2.4.3: Aug 23 2001</h3>
767<ul>
768 <li>XML Catalog support see the doc</li>
769 <li>New NaN/Infinity floating point code</li>
770 <li>A few bug fixes</li>
771</ul>
772
773<h3>2.4.2: Aug 15 2001</h3>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]774<ul>
775 <li>adds xmlLineNumbersDefault() to control line number generation</li>
776 <li>lot of bug fixes</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]777 <li>the Microsoft MSC projects files should now be up to date</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]778 <li>inheritance of namespaces from DTD defaulted attributes</li>
779 <li>fixes a serious potential security bug</li>
780 <li>added a --format option to xmllint</li>
781</ul>
782
783<h3>2.4.1: July 24 2001</h3>
784<ul>
785 <li>possibility to keep line numbers in the tree</li>
786 <li>some computation NaN fixes</li>
787 <li>extension of the XPath API</li>
788 <li>cleanup for alpha and ia64 targets</li>
789 <li>patch to allow saving through HTTP PUT or POST</li>
Daniel Veillard09ab7e12001-07-10 15:49:44 +0000[diff] [blame]790</ul>
791
792<h3>2.4.0: July 10 2001</h3>
793<ul>
794 <li>Fixed a few bugs in XPath, validation, and tree handling.</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]795 <li>Fixed XML Base implementation, added a couple of examples to the
Daniel Veillard09ab7e12001-07-10 15:49:44 +0000[diff] [blame]796 regression tests</li>
797 <li>A bit of cleanup</li>
Daniel Veillardab8500d2000-10-15 21:06:19 +0000[diff] [blame]798</ul>
799
Daniel Veillard5b43fde2001-07-05 23:31:40 +0000[diff] [blame]800<h3>2.3.14: July 5 2001</h3>
801<ul>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]802 <li>fixed some entities problems and reduce memory requirement when
803 substituting them</li>
Daniel Veillard5b43fde2001-07-05 23:31:40 +0000[diff] [blame]804 <li>lots of improvements in the XPath queries interpreter can be
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]805 substantially faster</li>
Daniel Veillard5b43fde2001-07-05 23:31:40 +0000[diff] [blame]806 <li>Makefiles and configure cleanups</li>
807 <li>Fixes to XPath variable eval, and compare on empty node set</li>
808 <li>HTML tag closing bug fixed</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]809 <li>Fixed an URI reference computation problem when validating</li>
Daniel Veillard5b43fde2001-07-05 23:31:40 +0000[diff] [blame]810</ul>
811
Daniel Veillard2adbb512001-06-28 16:20:36 +0000[diff] [blame]812<h3>2.3.13: June 28 2001</h3>
813<ul>
814 <li>2.3.12 configure.in was broken as well as the push mode XML parser</li>
815 <li>a few more fixes for compilation on Windows MSC by Yon Derek</li>
816</ul>
817
818<h3>1.8.14: June 28 2001</h3>
819<ul>
820 <li>Zbigniew Chyla gave a patch to use the old XML parser in push mode</li>
821 <li>Small Makefile fix</li>
822</ul>
823
Daniel Veillard11648102001-06-26 16:08:24 +0000[diff] [blame]824<h3>2.3.12: June 26 2001</h3>
825<ul>
826 <li>lots of cleanup</li>
827 <li>a couple of validation fix</li>
828 <li>fixed line number counting</li>
829 <li>fixed serious problems in the XInclude processing</li>
830 <li>added support for UTF8 BOM at beginning of entities</li>
831 <li>fixed a strange gcc optimizer bugs in xpath handling of float, gcc-3.0
832 miscompile uri.c (William), Thomas Leitner provided a fix for the
833 optimizer on Tru64</li>
834 <li>incorporated Yon Derek and Igor Zlatkovic fixes and improvements for
835 compilation on Windows MSC</li>
836 <li>update of libxml-doc.el (Felix Natter)</li>
837 <li>fixed 2 bugs in URI normalization code</li>
838</ul>
839
Daniel Veillarde3c81b52001-06-17 14:50:34 +0000[diff] [blame]840<h3>2.3.11: June 17 2001</h3>
841<ul>
842 <li>updates to trio, Makefiles and configure should fix some portability
843 problems (alpha)</li>
844 <li>fixed some HTML serialization problems (pre, script, and block/inline
845 handling), added encoding aware APIs, cleanup of this code</li>
846 <li>added xmlHasNsProp()</li>
847 <li>implemented a specific PI for encoding support in the DocBook SGML
848 parser</li>
849 <li>some XPath fixes (-Infinity, / as a function parameter and namespaces
850 node selection)</li>
851 <li>fixed a performance problem and an error in the validation code</li>
852 <li>fixed XInclude routine to implement the recursive behaviour</li>
853 <li>fixed xmlFreeNode problem when libxml is included statically twice</li>
854 <li>added --version to xmllint for bug reports</li>
855</ul>
856
Daniel Veillard2e4f1882001-06-01 10:11:57 +0000[diff] [blame]857<h3>2.3.10: June 1 2001</h3>
858<ul>
859 <li>fixed the SGML catalog support</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]860 <li>a number of reported bugs got fixed, in XPath, iconv detection,
861 XInclude processing</li>
Daniel Veillard2e4f1882001-06-01 10:11:57 +0000[diff] [blame]862 <li>XPath string function should now handle unicode correctly</li>
863</ul>
864
Daniel Veillard4623acd2001-05-19 15:13:15 +0000[diff] [blame]865<h3>2.3.9: May 19 2001</h3>
866
867<p>Lots of bugfixes, and added a basic SGML catalog support:</p>
868<ul>
869 <li>HTML push bugfix #54891 and another patch from Jonas Borgström</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]870 <li>some serious speed optimization again</li>
Daniel Veillard4623acd2001-05-19 15:13:15 +0000[diff] [blame]871 <li>some documentation cleanups</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]872 <li>trying to get better linking on Solaris (-R)</li>
Daniel Veillard4623acd2001-05-19 15:13:15 +0000[diff] [blame]873 <li>XPath API cleanup from Thomas Broyer</li>
874 <li>Validation bug fixed #54631, added a patch from Gary Pennington, fixed
875 xmlValidGetValidElements()</li>
876 <li>Added an INSTALL file</li>
877 <li>Attribute removal added to API: #54433</li>
878 <li>added a basic support for SGML catalogs</li>
879 <li>fixed xmlKeepBlanksDefault(0) API</li>
880 <li>bugfix in xmlNodeGetLang()</li>
881 <li>fixed a small configure portability problem</li>
882 <li>fixed an inversion of SYSTEM and PUBLIC identifier in HTML document</li>
883</ul>
884
Daniel Veillarda265af72001-05-14 11:13:58 +0000[diff] [blame]885<h3>1.8.13: May 14 2001</h3>
886<ul>
887 <li>bugfixes release of the old libxml1 branch used by Gnome</li>
888</ul>
889
Daniel Veillard3bbbe6f2001-05-03 11:15:37 +0000[diff] [blame]890<h3>2.3.8: May 3 2001</h3>
891<ul>
892 <li>Integrated an SGML DocBook parser for the Gnome project</li>
893 <li>Fixed a few things in the HTML parser</li>
894 <li>Fixed some XPath bugs raised by XSLT use, tried to fix the floating
895 point portability issue</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]896 <li>Speed improvement (8M/s for SAX, 3M/s for DOM, 1.5M/s for
897 DOM+validation using the XML REC as input and a 700MHz celeron).</li>
Daniel Veillard3bbbe6f2001-05-03 11:15:37 +0000[diff] [blame]898 <li>incorporated more Windows cleanup</li>
899 <li>added xmlSaveFormatFile()</li>
900 <li>fixed problems in copying nodes with entities references (gdome)</li>
901 <li>removed some troubles surrounding the new validation module</li>
902</ul>
903
Daniel Veillarda41123c2001-04-22 19:31:20 +0000[diff] [blame]904<h3>2.3.7: April 22 2001</h3>
905<ul>
906 <li>lots of small bug fixes, corrected XPointer</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]907 <li>Non deterministic content model validation support</li>
Daniel Veillarda41123c2001-04-22 19:31:20 +0000[diff] [blame]908 <li>added xmlDocCopyNode for gdome2</li>
909 <li>revamped the way the HTML parser handles end of tags</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]910 <li>XPath: corrections of namespaces support and number formatting</li>
Daniel Veillarda41123c2001-04-22 19:31:20 +0000[diff] [blame]911 <li>Windows: Igor Zlatkovic patches for MSC compilation</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]912 <li>HTML output fixes from P C Chow and William M. Brack</li>
Daniel Veillarda41123c2001-04-22 19:31:20 +0000[diff] [blame]913 <li>Improved validation speed sensible for DocBook</li>
914 <li>fixed a big bug with ID declared in external parsed entities</li>
915 <li>portability fixes, update of Trio from Bjorn Reese</li>
916</ul>
917
Daniel Veillardafc73112001-04-11 11:51:41 +0000[diff] [blame]918<h3>2.3.6: April 8 2001</h3>
919<ul>
920 <li>Code cleanup using extreme gcc compiler warning options, found and
921 cleared half a dozen potential problem</li>
922 <li>the Eazel team found an XML parser bug</li>
923 <li>cleaned up the user of some of the string formatting function. used the
924 trio library code to provide the one needed when the platform is missing
925 them</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]926 <li>xpath: removed a memory leak and fixed the predicate evaluation
927 problem, extended the testsuite and cleaned up the result. XPointer seems
928 broken ...</li>
Daniel Veillardafc73112001-04-11 11:51:41 +0000[diff] [blame]929</ul>
930
Daniel Veillard56a4cb82001-03-24 17:00:36 +0000[diff] [blame]931<h3>2.3.5: Mar 23 2001</h3>
932<ul>
933 <li>Biggest change is separate parsing and evaluation of XPath expressions,
934 there is some new APIs for this too</li>
935 <li>included a number of bug fixes(XML push parser, 51876, notations,
936 52299)</li>
937 <li>Fixed some portability issues</li>
938</ul>
939
Daniel Veillarde356c282001-03-10 12:32:04 +0000[diff] [blame]940<h3>2.3.4: Mar 10 2001</h3>
941<ul>
942 <li>Fixed bugs #51860 and #51861</li>
943 <li>Added a global variable xmlDefaultBufferSize to allow default buffer
944 size to be application tunable.</li>
945 <li>Some cleanup in the validation code, still a bug left and this part
946 should probably be rewritten to support ambiguous content model :-\</li>
947 <li>Fix a couple of serious bugs introduced or raised by changes in 2.3.3
948 parser</li>
949 <li>Fixed another bug in xmlNodeGetContent()</li>
950 <li>Bjorn fixed XPath node collection and Number formatting</li>
951 <li>Fixed a loop reported in the HTML parsing</li>
952 <li>blank space are reported even if the Dtd content model proves that they
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]953 are formatting spaces, this is for XML conformance</li>
Daniel Veillarde356c282001-03-10 12:32:04 +0000[diff] [blame]954</ul>
955
Daniel Veillardb402c072001-03-01 17:28:58 +0000[diff] [blame]956<h3>2.3.3: Mar 1 2001</h3>
957<ul>
958 <li>small change in XPath for XSLT</li>
959 <li>documentation cleanups</li>
960 <li>fix in validation by Gary Pennington</li>
961 <li>serious parsing performances improvements</li>
962</ul>
963
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]964<h3>2.3.2: Feb 24 2001</h3>
Daniel Veillard71681102001-02-24 17:48:53 +0000[diff] [blame]965<ul>
966 <li>chasing XPath bugs, found a bunch, completed some TODO</li>
967 <li>fixed a Dtd parsing bug</li>
968 <li>fixed a bug in xmlNodeGetContent</li>
969 <li>ID/IDREF support partly rewritten by Gary Pennington</li>
970</ul>
971
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]972<h3>2.3.1: Feb 15 2001</h3>
Daniel Veillard6e6a6cc2001-02-15 15:55:44 +0000[diff] [blame]973<ul>
974 <li>some XPath and HTML bug fixes for XSLT</li>
975 <li>small extension of the hash table interfaces for DOM gdome2
976 implementation</li>
977 <li>A few bug fixes</li>
978</ul>
979
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]980<h3>2.3.0: Feb 8 2001 (2.2.12 was on 25 Jan but I didn't kept track)</h3>
Daniel Veillard6e6a6cc2001-02-15 15:55:44 +0000[diff] [blame]981<ul>
982 <li>Lots of XPath bug fixes</li>
983 <li>Add a mode with Dtd lookup but without validation error reporting for
984 XSLT</li>
985 <li>Add support for text node without escaping (XSLT)</li>
986 <li>bug fixes for xmlCheckFilename</li>
987 <li>validation code bug fixes from Gary Pennington</li>
988 <li>Patch from Paul D. Smith correcting URI path normalization</li>
989 <li>Patch to allow simultaneous install of libxml-devel and
990 libxml2-devel</li>
991 <li>the example Makefile is now fixed</li>
992 <li>added HTML to the RPM packages</li>
993 <li>tree copying bugfixes</li>
994 <li>updates to Windows makefiles</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]995 <li>optimization patch from Bjorn Reese</li>
Daniel Veillard6e6a6cc2001-02-15 15:55:44 +0000[diff] [blame]996</ul>
997
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]998<h3>2.2.11: Jan 4 2001</h3>
Daniel Veillard503b8932001-01-05 06:36:31 +0000[diff] [blame]999<ul>
1000 <li>bunch of bug fixes (memory I/O, xpath, ftp/http, ...)</li>
1001 <li>added htmlHandleOmittedElem()</li>
1002 <li>Applied Bjorn Reese's IPV6 first patch</li>
1003 <li>Applied Paul D. Smith patches for validation of XInclude results</li>
Daniel Veillard82687162001-01-22 15:32:01 +0000[diff] [blame]1004 <li>added XPointer xmlns() new scheme support</li>
Daniel Veillard503b8932001-01-05 06:36:31 +0000[diff] [blame]1005</ul>
1006
Daniel Veillard2ddd23d2000-11-25 10:42:19 +0000[diff] [blame]1007<h3>2.2.10: Nov 25 2000</h3>
Daniel Veillard9d343c42000-11-25 10:12:43 +0000[diff] [blame]1008<ul>
1009 <li>Fix the Windows problems of 2.2.8</li>
1010 <li>integrate OpenVMS patches</li>
1011 <li>better handling of some nasty HTML input</li>
1012 <li>Improved the XPointer implementation</li>
1013 <li>integrate a number of provided patches</li>
1014</ul>
1015
Daniel Veillard2ddd23d2000-11-25 10:42:19 +0000[diff] [blame]1016<h3>2.2.9: Nov 25 2000</h3>
1017<ul>
1018 <li>erroneous release :-(</li>
1019</ul>
1020
Daniel Veillard28929b22000-11-13 18:22:49 +0000[diff] [blame]1021<h3>2.2.8: Nov 13 2000</h3>
1022<ul>
1023 <li>First version of <a href="http://www.w3.org/TR/xinclude">XInclude</a>
1024 support</li>
1025 <li>Patch in conditional section handling</li>
1026 <li>updated MS compiler project</li>
1027 <li>fixed some XPath problems</li>
1028 <li>added an URI escaping function</li>
1029 <li>some other bug fixes</li>
1030</ul>
1031
1032<h3>2.2.7: Oct 31 2000</h3>
1033<ul>
1034 <li>added message redirection</li>
1035 <li>XPath improvements (thanks TOM !)</li>
1036 <li>xmlIOParseDTD() added</li>
1037 <li>various small fixes in the HTML, URI, HTTP and XPointer support</li>
1038 <li>some cleanup of the Makefile, autoconf and the distribution content</li>
1039</ul>
1040
Daniel Veillard29a11cc2000-10-25 13:32:39 +0000[diff] [blame]1041<h3>2.2.6: Oct 25 2000:</h3>
1042<ul>
1043 <li>Added an hash table module, migrated a number of internal structure to
1044 those</li>
1045 <li>Fixed a posteriori validation problems</li>
1046 <li>HTTP module cleanups</li>
1047 <li>HTML parser improvements (tag errors, script/style handling, attribute
1048 normalization)</li>
1049 <li>coalescing of adjacent text nodes</li>
1050 <li>couple of XPath bug fixes, exported the internal API</li>
1051</ul>
1052
Daniel Veillardab8500d2000-10-15 21:06:19 +0000[diff] [blame]1053<h3>2.2.5: Oct 15 2000:</h3>
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000[diff] [blame]1054<ul>
Daniel Veillard189446d2000-10-13 10:23:06 +0000[diff] [blame]1055 <li>XPointer implementation and testsuite</li>
1056 <li>Lot of XPath fixes, added variable and functions registration, more
1057 tests</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]1058 <li>Portability fixes, lots of enhancements toward an easy Windows build
1059 and release</li>
Daniel Veillard189446d2000-10-13 10:23:06 +0000[diff] [blame]1060 <li>Late validation fixes</li>
1061 <li>Integrated a lot of contributed patches</li>
1062 <li>added memory management docs</li>
Daniel Veillardab8500d2000-10-15 21:06:19 +0000[diff] [blame]1063 <li>a performance problem when using large buffer seems fixed</li>
Daniel Veillard189446d2000-10-13 10:23:06 +0000[diff] [blame]1064</ul>
1065
1066<h3>2.2.4: Oct 1 2000:</h3>
1067<ul>
1068 <li>main XPath problem fixed</li>
1069 <li>Integrated portability patches for Windows</li>
1070 <li>Serious bug fixes on the URI and HTML code</li>
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]1071</ul>
1072
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]1073<h3>2.2.3: Sep 17 2000</h3>
1074<ul>
1075 <li>bug fixes</li>
1076 <li>cleanup of entity handling code</li>
1077 <li>overall review of all loops in the parsers, all sprintf usage has been
1078 checked too</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1079 <li>Far better handling of larges Dtd. Validating against DocBook XML Dtd
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]1080 works smoothly now.</li>
1081</ul>
1082
1083<h3>1.8.10: Sep 6 2000</h3>
1084<ul>
1085 <li>bug fix release for some Gnome projects</li>
1086</ul>
1087
1088<h3>2.2.2: August 12 2000</h3>
Daniel Veillard786d7c82000-08-12 23:38:57 +0000[diff] [blame]1089<ul>
1090 <li>mostly bug fixes</li>
Daniel Veillardec78c0f2000-08-25 10:25:23 +0000[diff] [blame]1091 <li>started adding routines to access xml parser context options</li>
Daniel Veillard786d7c82000-08-12 23:38:57 +0000[diff] [blame]1092</ul>
1093
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]1094<h3>2.2.1: July 21 2000</h3>
Daniel Veillarda2679fa2000-07-22 02:38:15 +0000[diff] [blame]1095<ul>
1096 <li>a purely bug fixes release</li>
1097 <li>fixed an encoding support problem when parsing from a memory block</li>
1098 <li>fixed a DOCTYPE parsing problem</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]1099 <li>removed a bug in the function allowing to override the memory
1100 allocation routines</li>
Daniel Veillarda2679fa2000-07-22 02:38:15 +0000[diff] [blame]1101</ul>
1102
Daniel Veillardd5f97f82000-09-17 16:38:14 +0000[diff] [blame]1103<h3>2.2.0: July 14 2000</h3>
Daniel Veillard94e90602000-07-17 14:38:19 +0000[diff] [blame]1104<ul>
1105 <li>applied a lot of portability fixes</li>
1106 <li>better encoding support/cleanup and saving (content is now always
1107 encoded in UTF-8)</li>
1108 <li>the HTML parser now correctly handles encodings</li>
1109 <li>added xmlHasProp()</li>
1110 <li>fixed a serious problem with &amp;#38;</li>
1111 <li>propagated the fix to FTP client</li>
1112 <li>cleanup, bugfixes, etc ...</li>
1113 <li>Added a page about <a href="encoding.html">libxml Internationalization
1114 support</a></li>
1115</ul>
1116
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1117<h3>1.8.9: July 9 2000</h3>
1118<ul>
1119 <li>fixed the spec the RPMs should be better</li>
1120 <li>fixed a serious bug in the FTP implementation, released 1.8.9 to solve
1121 rpmfind users problem</li>
1122</ul>
1123
Daniel Veillard6388e172000-07-03 16:07:19 +0000[diff] [blame]1124<h3>2.1.1: July 1 2000</h3>
1125<ul>
1126 <li>fixes a couple of bugs in the 2.1.0 packaging</li>
1127 <li>improvements on the HTML parser</li>
1128</ul>
1129
Daniel Veillard3f6f7f62000-06-30 17:58:25 +0000[diff] [blame]1130<h3>2.1.0 and 1.8.8: June 29 2000</h3>
1131<ul>
Daniel Veillardc0801af2002-05-28 16:28:42 +0000[diff] [blame]1132 <li>1.8.8 is mostly a commodity package for upgrading to libxml2 according
1133 to <a href="upgrade.html">new instructions</a>. It fixes a nasty problem
Daniel Veillard3f6f7f62000-06-30 17:58:25 +0000[diff] [blame]1134 about &amp;#38; charref parsing</li>
1135 <li>2.1.0 also ease the upgrade from libxml v1 to the recent version. it
1136 also contains numerous fixes and enhancements:
1137 <ul>
1138 <li>added xmlStopParser() to stop parsing</li>
1139 <li>improved a lot parsing speed when there is large CDATA blocs</li>
1140 <li>includes XPath patches provided by Picdar Technology</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1141 <li>tried to fix as much as possible DTD validation and namespace
Daniel Veillard3f6f7f62000-06-30 17:58:25 +0000[diff] [blame]1142 related problems</li>
1143 <li>output to a given encoding has been added/tested</li>
1144 <li>lot of various fixes</li>
1145 </ul>
1146 </li>
1147</ul>
1148
Daniel Veillarde0aed302000-04-16 08:52:20 +0000[diff] [blame]1149<h3>2.0.0: Apr 12 2000</h3>
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]1150<ul>
1151 <li>First public release of libxml2. If you are using libxml, it's a good
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1152 idea to check the 1.x to 2.x upgrade instructions. NOTE: while initially
1153 scheduled for Apr 3 the release occurred only on Apr 12 due to massive
Daniel Veillarde0aed302000-04-16 08:52:20 +0000[diff] [blame]1154 workload.</li>
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]1155 <li>The include are now located under $prefix/include/libxml (instead of
Daniel Veillarde0aed302000-04-16 08:52:20 +0000[diff] [blame]1156 $prefix/include/gnome-xml), they also are referenced by
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1157 <pre>#include &lt;libxml/xxx.h&gt;</pre>
Daniel Veillarde0aed302000-04-16 08:52:20 +0000[diff] [blame]1158 <p>instead of</p>
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]1159 <pre>#include "xxx.h"</pre>
1160 </li>
Daniel Veillard8f621982000-03-20 13:07:15 +0000[diff] [blame]1161 <li>a new URI module for parsing URIs and following strictly RFC 2396</li>
1162 <li>the memory allocation routines used by libxml can now be overloaded
1163 dynamically by using xmlMemSetup()</li>
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]1164 <li>The previously CVS only tool tester has been renamed
1165 <strong>xmllint</strong> and is now installed as part of the libxml2
1166 package</li>
Daniel Veillarde0aed302000-04-16 08:52:20 +0000[diff] [blame]1167 <li>The I/O interface has been revamped. There is now ways to plug in
1168 specific I/O modules, either at the URI scheme detection level using
1169 xmlRegisterInputCallbacks() or by passing I/O functions when creating a
1170 parser context using xmlCreateIOParserCtxt()</li>
1171 <li>there is a C preprocessor macro LIBXML_VERSION providing the version
1172 number of the libxml module in use</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]1173 <li>a number of optional features of libxml can now be excluded at
1174 configure time (FTP/HTTP/HTML/XPath/Debug)</li>
Daniel Veillardedfb29b2000-03-14 19:59:05 +0000[diff] [blame]1175</ul>
1176
1177<h3>2.0.0beta: Mar 14 2000</h3>
1178<ul>
1179 <li>This is a first Beta release of libxml version 2</li>
Daniel Veillarde356c282001-03-10 12:32:04 +0000[diff] [blame]1180 <li>It's available only from<a href="ftp://xmlsoft.org/">xmlsoft.org
1181 FTP</a>, it's packaged as libxml2-2.0.0beta and available as tar and
1182 RPMs</li>
Daniel Veillardedfb29b2000-03-14 19:59:05 +0000[diff] [blame]1183 <li>This version is now the head in the Gnome CVS base, the old one is
1184 available under the tag LIB_XML_1_X</li>
Daniel Veillardc0801af2002-05-28 16:28:42 +0000[diff] [blame]1185 <li>This includes a very large set of changes. From a programmatic point
1186 of view applications should not have to be modified too much, check the
1187 <a href="upgrade.html">upgrade page</a></li>
Daniel Veillardedfb29b2000-03-14 19:59:05 +0000[diff] [blame]1188 <li>Some interfaces may changes (especially a bit about encoding).</li>
1189 <li>the updates includes:
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]1190 <ul>
Daniel Veillardedfb29b2000-03-14 19:59:05 +0000[diff] [blame]1191 <li>fix I18N support. ISO-Latin-x/UTF-8/UTF-16 (nearly) seems correctly
1192 handled now</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1193 <li>Better handling of entities, especially well-formedness checking
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]1194 and proper PEref extensions in external subsets</li>
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]1195 <li>DTD conditional sections</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1196 <li>Validation now correctly handle entities content</li>
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]1197 <li><a href="http://rpmfind.net/tools/gdome/messages/0039.html">change
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1198 structures to accommodate DOM</a></li>
Daniel Veillard6c8b1172000-03-01 00:40:41 +0000[diff] [blame]1199 </ul>
1200 </li>
Daniel Veillardedfb29b2000-03-14 19:59:05 +0000[diff] [blame]1201 <li>Serious progress were made toward compliance, <a
1202 href="conf/result.html">here are the result of the test</a> against the
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1203 OASIS testsuite (except the Japanese tests since I don't support that
Daniel Veillardedfb29b2000-03-14 19:59:05 +0000[diff] [blame]1204 encoding yet). This URL is rebuilt every couple of hours using the CVS
1205 head version.</li>
Daniel Veillarde41f2b72000-01-30 20:00:07 +0000[diff] [blame]1206</ul>
1207
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1208<h3>1.8.7: Mar 6 2000</h3>
1209<ul>
1210 <li>This is a bug fix release:</li>
1211 <li>It is possible to disable the ignorable blanks heuristic used by
1212 libxml-1.x, a new function xmlKeepBlanksDefault(0) will allow this. Note
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]1213 that for adherence to XML spec, this behaviour will be disabled by
1214 default in 2.x . The same function will allow to keep compatibility for
1215 old code.</li>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1216 <li>Blanks in &lt;a&gt; &lt;/a&gt; constructs are not ignored anymore,
1217 avoiding heuristic is really the Right Way :-\</li>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1218 <li>The unchecked use of snprintf which was breaking libxml-1.8.6
1219 compilation on some platforms has been fixed</li>
1220 <li>nanoftp.c nanohttp.c: Fixed '#' and '?' stripping when processing
1221 URIs</li>
1222</ul>
1223
Daniel Veillarde41f2b72000-01-30 20:00:07 +0000[diff] [blame]1224<h3>1.8.6: Jan 31 2000</h3>
1225<ul>
1226 <li>added a nanoFTP transport module, debugged until the new version of <a
1227 href="http://rpmfind.net/linux/rpm2html/rpmfind.html">rpmfind</a> can use
1228 it without troubles</li>
Daniel Veillardda07c342000-01-25 18:31:22 +0000[diff] [blame]1229</ul>
1230
1231<h3>1.8.5: Jan 21 2000</h3>
1232<ul>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]1233 <li>adding APIs to parse a well balanced chunk of XML (production <a
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]1234 href="http://www.w3.org/TR/REC-xml#NT-content">[43] content</a> of the
1235 XML spec)</li>
Daniel Veillard461a66c2000-01-18 18:01:01 +0000[diff] [blame]1236 <li>fixed a hideous bug in xmlGetProp pointed by Rune.Djurhuus@fast.no</li>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1237 <li>Jody Goldberg &lt;jgoldberg@home.com&gt; provided another patch trying
1238 to solve the zlib checks problems</li>
Daniel Veillard461a66c2000-01-18 18:01:01 +0000[diff] [blame]1239 <li>The current state in gnome CVS base is expected to ship as 1.8.5 with
1240 gnumeric soon</li>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]1241</ul>
1242
1243<h3>1.8.4: Jan 13 2000</h3>
1244<ul>
1245 <li>bug fixes, reintroduced xmlNewGlobalNs(), fixed xmlNewNs()</li>
1246 <li>all exit() call should have been removed from libxml</li>
1247 <li>fixed a problem with INCLUDE_WINSOCK on WIN32 platform</li>
1248 <li>added newDocFragment()</li>
Daniel Veillardf84f71f2000-01-05 19:54:23 +0000[diff] [blame]1249</ul>
1250
1251<h3>1.8.3: Jan 5 2000</h3>
1252<ul>
1253 <li>a Push interface for the XML and HTML parsers</li>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1254 <li>a shell-like interface to the document tree (try tester --shell :-)</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1255 <li>lots of bug fixes and improvement added over XMas holidays</li>
Daniel Veillard437b87b2000-01-03 17:30:46 +0000[diff] [blame]1256 <li>fixed the DTD parsing code to work with the xhtml DTD</li>
Daniel Veillardf84f71f2000-01-05 19:54:23 +0000[diff] [blame]1257 <li>added xmlRemoveProp(), xmlRemoveID() and xmlRemoveRef()</li>
1258 <li>Fixed bugs in xmlNewNs()</li>
Daniel Veillard437b87b2000-01-03 17:30:46 +0000[diff] [blame]1259 <li>External entity loading code has been revamped, now it uses
Daniel Veillardf84f71f2000-01-05 19:54:23 +0000[diff] [blame]1260 xmlLoadExternalEntity(), some fix on entities processing were added</li>
Daniel Veillard437b87b2000-01-03 17:30:46 +0000[diff] [blame]1261 <li>cleaned up WIN32 includes of socket stuff</li>
Daniel Veillard5cb5ab81999-12-21 15:35:29 +0000[diff] [blame]1262</ul>
1263
1264<h3>1.8.2: Dec 21 1999</h3>
1265<ul>
Daniel Veillardb24054a1999-12-18 15:32:46 +0000[diff] [blame]1266 <li>I got another problem with includes and C++, I hope this issue is fixed
1267 for good this time</li>
Daniel Veillard5cb5ab81999-12-21 15:35:29 +0000[diff] [blame]1268 <li>Added a few tree modification functions: xmlReplaceNode,
1269 xmlAddPrevSibling, xmlAddNextSibling, xmlNodeSetName and
1270 xmlDocSetRootElement</li>
1271 <li>Tried to improve the HTML output with help from <a
1272 href="mailto:clahey@umich.edu">Chris Lahey</a></li>
Daniel Veillarde4e51311999-12-18 15:32:46 +0000[diff] [blame]1273</ul>
Daniel Veillardb24054a1999-12-18 15:32:46 +0000[diff] [blame]1274
Daniel Veillarde4e51311999-12-18 15:32:46 +0000[diff] [blame]1275<h3>1.8.1: Dec 18 1999</h3>
1276<ul>
1277 <li>various patches to avoid troubles when using libxml with C++ compilers
1278 the "namespace" keyword and C escaping in include files</li>
1279 <li>a problem in one of the core macros IS_CHAR was corrected</li>
1280 <li>fixed a bug introduced in 1.8.0 breaking default namespace processing,
1281 and more specifically the Dia application</li>
Daniel Veillard944b5ff1999-12-15 19:08:24 +0000[diff] [blame]1282 <li>fixed a posteriori validation (validation after parsing, or by using a
1283 Dtd not specified in the original document)</li>
Daniel Veillardb24054a1999-12-18 15:32:46 +0000[diff] [blame]1284 <li>fixed a bug in</li>
Daniel Veillard10a2c651999-12-12 13:03:50 +0000[diff] [blame]1285</ul>
1286
1287<h3>1.8.0: Dec 12 1999</h3>
1288<ul>
1289 <li>cleanup, especially memory wise</li>
1290 <li>the parser should be more reliable, especially the HTML one, it should
1291 not crash, whatever the input !</li>
1292 <li>Integrated various patches, especially a speedup improvement for large
1293 dataset from <a href="mailto:cnygard@bellatlantic.net">Carl Nygard</a>,
1294 configure with --with-buffers to enable them.</li>
1295 <li>attribute normalization, oops should have been added long ago !</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1296 <li>attributes defaulted from DTDs should be available, xmlSetProp() now
1297 does entities escaping by default.</li>
Daniel Veillard4c3a2031999-11-19 17:46:26 +0000[diff] [blame]1298</ul>
Daniel Veillard35008381999-10-25 13:15:52 +0000[diff] [blame]1299
1300<h3>1.7.4: Oct 25 1999</h3>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]1301<ul>
Daniel Veillard35008381999-10-25 13:15:52 +0000[diff] [blame]1302 <li>Lots of HTML improvement</li>
1303 <li>Fixed some errors when saving both XML and HTML</li>
1304 <li>More examples, the regression tests should now look clean</li>
1305 <li>Fixed a bug with contiguous charref</li>
1306</ul>
1307
1308<h3>1.7.3: Sep 29 1999</h3>
1309<ul>
1310 <li>portability problems fixed</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1311 <li>snprintf was used unconditionally, leading to link problems on system
Daniel Veillard35008381999-10-25 13:15:52 +0000[diff] [blame]1312 were it's not available, fixed</li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]1313</ul>
1314
1315<h3>1.7.1: Sep 24 1999</h3>
1316<ul>
1317 <li>The basic type for strings manipulated by libxml has been renamed in
1318 1.7.1 from <strong>CHAR</strong> to <strong>xmlChar</strong>. The reason
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]1319 is that CHAR was conflicting with a predefined type on Windows. However
1320 on non WIN32 environment, compatibility is provided by the way of a
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]1321 <strong>#define </strong>.</li>
1322 <li>Changed another error : the use of a structure field called errno, and
1323 leading to troubles on platforms where it's a macro</li>
1324</ul>
1325
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1326<h3>1.7.0: Sep 23 1999</h3>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]1327<ul>
1328 <li>Added the ability to fetch remote DTD or parsed entities, see the <a
Daniel Veillard9cb5ff42001-01-29 08:22:21 +0000[diff] [blame]1329 href="html/libxml-nanohttp.html">nanohttp</a> module.</li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]1330 <li>Added an errno to report errors by another mean than a simple printf
1331 like callback</li>
1332 <li>Finished ID/IDREF support and checking when validation</li>
1333 <li>Serious memory leaks fixed (there is now a <a
Daniel Veillard9cb5ff42001-01-29 08:22:21 +0000[diff] [blame]1334 href="html/libxml-xmlmemory.html">memory wrapper</a> module)</li>
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]1335 <li>Improvement of <a href="http://www.w3.org/TR/xpath">XPath</a>
1336 implementation</li>
1337 <li>Added an HTML parser front-end</li>
1338</ul>
1339
1340<h2><a name="XML">XML</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1341
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]1342<p><a href="http://www.w3.org/TR/REC-xml">XML is a standard</a> for
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1343markup-based structured documents. Here is <a name="example">an example XML
1344document</a>:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]1345<pre>&lt;?xml version="1.0"?&gt;
1346&lt;EXAMPLE prop1="gnome is great" prop2="&amp;amp; linux too"&gt;
1347 &lt;head&gt;
1348 &lt;title&gt;Welcome to Gnome&lt;/title&gt;
1349 &lt;/head&gt;
1350 &lt;chapter&gt;
1351 &lt;title&gt;The Linux adventure&lt;/title&gt;
1352 &lt;p&gt;bla bla bla ...&lt;/p&gt;
1353 &lt;image href="linus.gif"/&gt;
1354 &lt;p&gt;...&lt;/p&gt;
1355 &lt;/chapter&gt;
1356&lt;/EXAMPLE&gt;</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1357
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]1358<p>The first line specifies that it's an XML document and gives useful
1359information about its encoding. Then the document is a text format whose
1360structure is specified by tags between brackets. <strong>Each tag opened has
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1361to be closed</strong>. XML is pedantic about this. However, if a tag is empty
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]1362(no content), a single tag can serve as both the opening and closing tag if
1363it ends with <code>/&gt;</code> rather than with <code>&gt;</code>. Note
1364that, for example, the image tag has no content (just an attribute) and is
1365closed by ending the tag with <code>/&gt;</code>.</p>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]1366
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1367<p>XML can be applied successfully to a wide range of uses, from long term
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]1368structured document maintenance (where it follows the steps of SGML) to
1369simple data encoding mechanisms like configuration file formatting (glade),
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1370spreadsheets (gnumeric), or even shorter lived documents such as WebDAV where
1371it is used to encode remote calls between a client and a server.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1372
Daniel Veillard82687162001-01-22 15:32:01 +0000[diff] [blame]1373<h2><a name="XSLT">XSLT</a></h2>
1374
Daniel Veillard6e6a6cc2001-02-15 15:55:44 +0000[diff] [blame]1375<p>Check <a href="http://xmlsoft.org/XSLT">the separate libxslt page</a></p>
1376
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]1377<p><a href="http://www.w3.org/TR/xslt">XSL Transformations</a>, is a
1378language for transforming XML documents into other XML documents (or
1379HTML/textual output).</p>
Daniel Veillard82687162001-01-22 15:32:01 +0000[diff] [blame]1380
1381<p>A separate library called libxslt is being built on top of libxml2. This
1382module "libxslt" can be found in the Gnome CVS base too.</p>
1383
Daniel Veillard383b1472001-01-23 11:39:52 +0000[diff] [blame]1384<p>You can check the <a
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]1385href="http://cvs.gnome.org/lxr/source/libxslt/FEATURES">features</a>
1386supported and the progresses on the <a
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1387href="http://cvs.gnome.org/lxr/source/libxslt/ChangeLog"
1388name="Changelog">Changelog</a></p>
1389
1390<h2><a name="Python">Python and bindings</a></h2>
1391
1392<p>There is a number of language bindings and wrappers available for libxml2,
1393the list below is not exhaustive. Please contact the <a
1394href="http://mail.gnome.org/mailman/listinfo/xml-bindings">xml-bindings@gnome.org</a>
1395(<a href="http://mail.gnome.org/archives/xml-bindings/">archives</a>) in
1396order to get updates to this list or to discuss the specific topic of libxml2
1397or libxslt wrappers or bindings:</p>
1398<ul>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]1399 <li><a href="mailto:ari@lusis.org">Ari Johnson</a> provides a C++ wrapper
1400 for libxml:<br>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1401 Website: <a
1402 href="http://lusis.org/~ari/xml++/">http://lusis.org/~ari/xml++/</a><br>
1403 Download: <a
1404 href="http://lusis.org/~ari/xml++/libxml++.tar.gz">http://lusis.org/~ari/xml++/libxml++.tar.gz</a></li>
1405 <li>There is another <a href="http://libgdome-cpp.berlios.de/">C++ wrapper
1406 based on the gdome2 </a>bindings maintained by Tobias Peters.</li>
Daniel Veillard9b6fd302002-05-13 12:06:47 +0000[diff] [blame]1407 <li>and a third C++ wrapper by Peter Jones &lt;pjones@pmade.org&gt;
1408 <p>Website: <a
1409 href="http://pmade.org/pjones/software/xmlwrapp/">http://pmade.org/pjones/software/xmlwrapp/</a></p>
1410 </li>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1411 <li><a
1412 href="http://mail.gnome.org/archives/xml/2001-March/msg00014.html">Matt
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1413 Sergeant</a> developed <a
1414 href="http://axkit.org/download/">XML::LibXSLT</a>, a Perl wrapper for
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]1415 libxml2/libxslt as part of the <a href="http://axkit.com/">AxKit XML
1416 application server</a></li>
1417 <li><a href="mailto:dkuhlman@cutter.rexx.com">Dave Kuhlman</a> provides and
1418 earlier version of the libxml/libxslt <a
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1419 href="http://www.rexx.com/~dkuhlman">wrappers for Python</a></li>
1420 <li>Petr Kozelka provides <a
1421 href="http://sourceforge.net/projects/libxml2-pas">Pascal units to glue
1422 libxml2</a> with Kylix, Delphi and other Pascal compilers</li>
Daniel Veillardb2fb8ed2002-04-01 09:33:12 +0000[diff] [blame]1423 <li>Uwe Fechner also provides <a
1424 href="http://sourceforge.net/projects/idom2-pas/">idom2</a>, a DOM2
Daniel Veillard75794822002-04-11 16:24:32 +0000[diff] [blame]1425 implementation for Kylix2/D5/D6 from Borland</li>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1426 <li>Wai-Sun "Squidster" Chia provides <a
1427 href="http://www.rubycolor.org/arc/redist/">bindings for Ruby</a> and
1428 libxml2 bindings are also available in Ruby through the <a
1429 href="http://libgdome-ruby.berlios.de/">libgdome-ruby</a> module
1430 maintained by Tobias Peters.</li>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]1431 <li>Steve Ball and contributors maintains <a
1432 href="http://tclxml.sourceforge.net/">libxml2 and libxslt bindings for
1433 Tcl</a></li>
1434 <li>There is support for libxml2 in the DOM module of PHP.</li>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1435</ul>
1436
Daniel Veillardc0801af2002-05-28 16:28:42 +0000[diff] [blame]1437<p>The distribution includes a set of Python bindings, which are guaranteed
1438to be maintained as part of the library in the future, though the Python
Daniel Veillard0b79dfe2002-02-23 13:02:31 +0000[diff] [blame]1439interface have not yet reached the maturity of the C API.</p>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]1440
1441<p>To install the Python bindings there are 2 options:</p>
Daniel Veillard0b79dfe2002-02-23 13:02:31 +0000[diff] [blame]1442<ul>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]1443 <li>If you use an RPM based distribution, simply install the <a
1444 href="http://rpmfind.net/linux/rpm2html/search.php?query=libxml2-python">libxml2-python
1445 RPM</a> (and if needed the <a
1446 href="http://rpmfind.net/linux/rpm2html/search.php?query=libxslt-python">libxslt-python
1447 RPM</a>).</li>
1448 <li>Otherwise use the <a href="ftp://xmlsoft.org/python/">libxml2-python
1449 module distribution</a> corresponding to your installed version of
1450 libxml2 and libxslt. Note that to install it you will need both libxml2
1451 and libxslt installed and run "python setup.py build install" in the
1452 module tree.</li>
Daniel Veillard0b79dfe2002-02-23 13:02:31 +0000[diff] [blame]1453</ul>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]1454
1455<p>The distribution includes a set of examples and regression tests for the
1456python bindings in the <code>python/tests</code> directory. Here are some
1457excepts from those tests:</p>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1458
1459<h3>tst.py:</h3>
1460
1461<p>This is a basic test of the file interface and DOM navigation:</p>
1462<pre>import libxml2
1463
1464doc = libxml2.parseFile("tst.xml")
1465if doc.name != "tst.xml":
1466 print "doc.name failed"
1467 sys.exit(1)
1468root = doc.children
1469if root.name != "doc":
1470 print "root.name failed"
1471 sys.exit(1)
1472child = root.children
1473if child.name != "foo":
1474 print "child.name failed"
1475 sys.exit(1)
1476doc.freeDoc()</pre>
1477
1478<p>The Python module is called libxml2, parseFile is the equivalent of
1479xmlParseFile (most of the bindings are automatically generated, and the xml
1480prefix is removed and the casing convention are kept). All node seen at the
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1481binding level share the same subset of accessors:</p>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1482<ul>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]1483 <li><code>name</code> : returns the node name</li>
Daniel Veillardc0801af2002-05-28 16:28:42 +0000[diff] [blame]1484 <li><code>type</code> : returns a string indicating the node type</li>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]1485 <li><code>content</code> : returns the content of the node, it is based on
1486 xmlNodeGetContent() and hence is recursive.</li>
1487 <li><code>parent</code> , <code>children</code>, <code>last</code>,
1488 <code>next</code>, <code>prev</code>, <code>doc</code>,
1489 <code>properties</code>: pointing to the associated element in the tree,
1490 those may return None in case no such link exists.</li>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1491</ul>
1492
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1493<p>Also note the need to explicitly deallocate documents with freeDoc() .
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1494Reference counting for libxml2 trees would need quite a lot of work to
1495function properly, and rather than risk memory leaks if not implemented
1496correctly it sounds safer to have an explicit function to free a tree. The
1497wrapper python objects like doc, root or child are them automatically garbage
1498collected.</p>
1499
1500<h3>validate.py:</h3>
1501
1502<p>This test check the validation interfaces and redirection of error
1503messages:</p>
1504<pre>import libxml2
1505
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1506#deactivate error messages from the validation
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1507def noerr(ctx, str):
1508 pass
1509
1510libxml2.registerErrorHandler(noerr, None)
1511
1512ctxt = libxml2.createFileParserCtxt("invalid.xml")
1513ctxt.validate(1)
1514ctxt.parseDocument()
1515doc = ctxt.doc()
1516valid = ctxt.isValid()
1517doc.freeDoc()
1518if valid != 0:
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1519 print "validity check failed"</pre>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1520
1521<p>The first thing to notice is the call to registerErrorHandler(), it
1522defines a new error handler global to the library. It is used to avoid seeing
1523the error messages when trying to validate the invalid document.</p>
1524
1525<p>The main interest of that test is the creation of a parser context with
1526createFileParserCtxt() and how the behaviour can be changed before calling
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1527parseDocument() . Similarly the informations resulting from the parsing phase
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1528are also available using context methods.</p>
1529
1530<p>Contexts like nodes are defined as class and the libxml2 wrappers maps the
1531C function interfaces in terms of objects method as much as possible. The
1532best to get a complete view of what methods are supported is to look at the
1533libxml2.py module containing all the wrappers.</p>
1534
1535<h3>push.py:</h3>
1536
1537<p>This test show how to activate the push parser interface:</p>
1538<pre>import libxml2
1539
1540ctxt = libxml2.createPushParser(None, "&lt;foo", 4, "test.xml")
1541ctxt.parseChunk("/&gt;", 2, 1)
1542doc = ctxt.doc()
1543
1544doc.freeDoc()</pre>
1545
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1546<p>The context is created with a special call based on the
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1547xmlCreatePushParser() from the C library. The first argument is an optional
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1548SAX callback object, then the initial set of data, the length and the name of
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1549the resource in case URI-References need to be computed by the parser.</p>
1550
1551<p>Then the data are pushed using the parseChunk() method, the last call
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1552setting the third argument terminate to 1.</p>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1553
1554<h3>pushSAX.py:</h3>
1555
1556<p>this test show the use of the event based parsing interfaces. In this case
1557the parser does not build a document, but provides callback information as
1558the parser makes progresses analyzing the data being provided:</p>
1559<pre>import libxml2
1560log = ""
1561
1562class callback:
1563 def startDocument(self):
1564 global log
1565 log = log + "startDocument:"
1566
1567 def endDocument(self):
1568 global log
1569 log = log + "endDocument:"
1570
1571 def startElement(self, tag, attrs):
1572 global log
1573 log = log + "startElement %s %s:" % (tag, attrs)
1574
1575 def endElement(self, tag):
1576 global log
1577 log = log + "endElement %s:" % (tag)
1578
1579 def characters(self, data):
1580 global log
1581 log = log + "characters: %s:" % (data)
1582
1583 def warning(self, msg):
1584 global log
1585 log = log + "warning: %s:" % (msg)
1586
1587 def error(self, msg):
1588 global log
1589 log = log + "error: %s:" % (msg)
1590
1591 def fatalError(self, msg):
1592 global log
1593 log = log + "fatalError: %s:" % (msg)
1594
1595handler = callback()
1596
1597ctxt = libxml2.createPushParser(handler, "&lt;foo", 4, "test.xml")
1598chunk = " url='tst'&gt;b"
1599ctxt.parseChunk(chunk, len(chunk), 0)
1600chunk = "ar&lt;/foo&gt;"
1601ctxt.parseChunk(chunk, len(chunk), 1)
1602
Daniel Veillardfcbfa2d2002-02-21 17:54:27 +0000[diff] [blame]1603reference = "startDocument:startElement foo {'url': 'tst'}:" + \
1604 "characters: bar:endElement foo:endDocument:"
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1605if log != reference:
1606 print "Error got: %s" % log
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1607 print "Expected: %s" % reference</pre>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1608
1609<p>The key object in that test is the handler, it provides a number of entry
1610points which can be called by the parser as it makes progresses to indicate
1611the information set obtained. The full set of callback is larger than what
1612the callback class in that specific example implements (see the SAX
1613definition for a complete list). The wrapper will only call those supplied by
1614the object when activated. The startElement receives the names of the element
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1615and a dictionary containing the attributes carried by this element.</p>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1616
1617<p>Also note that the reference string generated from the callback shows a
1618single character call even though the string "bar" is passed to the parser
1619from 2 different call to parseChunk()</p>
1620
1621<h3>xpath.py:</h3>
1622
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1623<p>This is a basic test of XPath wrappers support</p>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1624<pre>import libxml2
1625
1626doc = libxml2.parseFile("tst.xml")
1627ctxt = doc.xpathNewContext()
1628res = ctxt.xpathEval("//*")
1629if len(res) != 2:
1630 print "xpath query: wrong node set size"
1631 sys.exit(1)
1632if res[0].name != "doc" or res[1].name != "foo":
1633 print "xpath query: wrong node set value"
1634 sys.exit(1)
1635doc.freeDoc()
1636ctxt.xpathFreeContext()</pre>
1637
1638<p>This test parses a file, then create an XPath context to evaluate XPath
1639expression on it. The xpathEval() method execute an XPath query and returns
1640the result mapped in a Python way. String and numbers are natively converted,
1641and node sets are returned as a tuple of libxml2 Python nodes wrappers. Like
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1642the document, the XPath context need to be freed explicitly, also not that
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1643the result of the XPath query may point back to the document tree and hence
1644the document must be freed after the result of the query is used.</p>
1645
1646<h3>xpathext.py:</h3>
1647
1648<p>This test shows how to extend the XPath engine with functions written in
1649python:</p>
1650<pre>import libxml2
1651
1652def foo(ctx, x):
1653 return x + 1
1654
1655doc = libxml2.parseFile("tst.xml")
1656ctxt = doc.xpathNewContext()
1657libxml2.registerXPathFunction(ctxt._o, "foo", None, foo)
1658res = ctxt.xpathEval("foo(1)")
1659if res != 2:
1660 print "xpath extension failure"
1661doc.freeDoc()
1662ctxt.xpathFreeContext()</pre>
1663
1664<p>Note how the extension function is registered with the context (but that
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1665part is not yet finalized, this may change slightly in the future).</p>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1666
1667<h3>tstxpath.py:</h3>
1668
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1669<p>This test is similar to the previous one but shows how the extension
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1670function can access the XPath evaluation context:</p>
1671<pre>def foo(ctx, x):
1672 global called
1673
1674 #
1675 # test that access to the XPath evaluation contexts
1676 #
1677 pctxt = libxml2.xpathParserContext(_obj=ctx)
1678 ctxt = pctxt.context()
1679 called = ctxt.function()
1680 return x + 1</pre>
1681
1682<p>All the interfaces around the XPath parser(or rather evaluation) context
1683are not finalized, but it should be sufficient to do contextual work at the
1684evaluation point.</p>
1685
1686<h3>Memory debugging:</h3>
1687
1688<p>last but not least, all tests starts with the following prologue:</p>
1689<pre>#memory debug specific
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]1690libxml2.debugMemory(1)</pre>
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1691
1692<p>and ends with the following epilogue:</p>
1693<pre>#memory debug specific
1694libxml2.cleanupParser()
1695if libxml2.debugMemory(1) == 0:
1696 print "OK"
1697else:
1698 print "Memory leak %d bytes" % (libxml2.debugMemory(1))
1699 libxml2.dumpMemory()</pre>
1700
1701<p>Those activate the memory debugging interface of libxml2 where all
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1702allocated block in the library are tracked. The prologue then cleans up the
Daniel Veillard6dbcaf82002-02-20 14:37:47 +0000[diff] [blame]1703library state and checks that all allocated memory has been freed. If not it
1704calls dumpMemory() which saves that list in a <code>.memdump</code> file.</p>
Daniel Veillard82687162001-01-22 15:32:01 +0000[diff] [blame]1705
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]1706<h2><a name="architecture">libxml architecture</a></h2>
Daniel Veillard4540be42000-08-19 16:40:28 +0000[diff] [blame]1707
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]1708<p>Libxml is made of multiple components; some of them are optional, and most
1709of the block interfaces are public. The main components are:</p>
Daniel Veillard4540be42000-08-19 16:40:28 +0000[diff] [blame]1710<ul>
1711 <li>an Input/Output layer</li>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]1712 <li>FTP and HTTP client layers (optional)</li>
Daniel Veillard4540be42000-08-19 16:40:28 +0000[diff] [blame]1713 <li>an Internationalization layer managing the encodings support</li>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]1714 <li>a URI module</li>
Daniel Veillard4540be42000-08-19 16:40:28 +0000[diff] [blame]1715 <li>the XML parser and its basic SAX interface</li>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]1716 <li>an HTML parser using the same SAX interface (optional)</li>
Daniel Veillard4540be42000-08-19 16:40:28 +0000[diff] [blame]1717 <li>a SAX tree module to build an in-memory DOM representation</li>
1718 <li>a tree module to manipulate the DOM representation</li>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]1719 <li>a validation module using the DOM representation (optional)</li>
Daniel Veillard4540be42000-08-19 16:40:28 +0000[diff] [blame]1720 <li>an XPath module for global lookup in a DOM representation
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]1721 (optional)</li>
1722 <li>a debug module (optional)</li>
Daniel Veillard4540be42000-08-19 16:40:28 +0000[diff] [blame]1723</ul>
1724
1725<p>Graphically this gives the following:</p>
1726
1727<p><img src="libxml.gif" alt="a graphical view of the various"></p>
1728
1729<p></p>
1730
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]1731<h2><a name="tree">The tree output</a></h2>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1732
1733<p>The parser returns a tree built during the document analysis. The value
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]1734returned is an <strong>xmlDocPtr</strong> (i.e., a pointer to an
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1735<strong>xmlDoc</strong> structure). This structure contains information such
Daniel Veillard306be992000-07-03 12:38:45 +0000[diff] [blame]1736as the file name, the document type, and a <strong>children</strong> pointer
1737which is the root of the document (or more exactly the first child under the
1738root which is the document). The tree is made of <strong>xmlNode</strong>s,
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]1739chained in double-linked lists of siblings and with a children&lt;-&gt;parent
Daniel Veillard306be992000-07-03 12:38:45 +0000[diff] [blame]1740relationship. An xmlNode can also carry properties (a chain of xmlAttr
1741structures). An attribute may have a value which is a list of TEXT or
1742ENTITY_REF nodes.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1743
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1744<p>Here is an example (erroneous with respect to the XML spec since there
1745should be only one ELEMENT under the root):</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1746
1747<p><img src="structure.gif" alt=" structure.gif "></p>
1748
1749<p>In the source package there is a small program (not installed by default)
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]1750called <strong>xmllint</strong> which parses XML files given as argument and
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1751prints them back as parsed. This is useful for detecting errors both in XML
1752code and in the XML parser itself. It has an option <strong>--debug</strong>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]1753which prints the actual in-memory structure of the document; here is the
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]1754result with the <a href="#example">example</a> given before:</p>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]1755<pre>DOCUMENT
1756version=1.0
1757standalone=true
1758 ELEMENT EXAMPLE
1759 ATTRIBUTE prop1
1760 TEXT
1761 content=gnome is great
1762 ATTRIBUTE prop2
1763 ENTITY_REF
1764 TEXT
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]1765 content= linux too
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]1766 ELEMENT head
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]1767 ELEMENT title
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]1768 TEXT
1769 content=Welcome to Gnome
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]1770 ELEMENT chapter
1771 ELEMENT title
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]1772 TEXT
1773 content=The Linux adventure
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]1774 ELEMENT p
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]1775 TEXT
1776 content=bla bla bla ...
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]1777 ELEMENT image
1778 ATTRIBUTE href
1779 TEXT
1780 content=linus.gif
1781 ELEMENT p
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]1782 TEXT
1783 content=...</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]1784
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1785<p>This should be useful for learning the internal representation model.</p>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]1786
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]1787<h2><a name="interface">The SAX interface</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1788
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]1789<p>Sometimes the DOM tree output is just too large to fit reasonably into
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1790memory. 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]1791loaded using libxml), it's better to use the SAX interface of libxml. SAX is
1792a <strong>callback-based interface</strong> to the parser. Before parsing,
1793the application layer registers a customized set of callbacks which are
1794called by the library as it progresses through the XML input.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1795
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1796<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]1797libxml, see the <a
1798href="http://www.daa.com.au/~james/gnome/xml-sax/xml-sax.html">nice
1799documentation</a>.written by <a href="mailto:james@daa.com.au">James
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1800Henstridge</a>.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1801
1802<p>You can debug the SAX behaviour by using the <strong>testSAX</strong>
1803program located in the gnome-xml module (it's usually not shipped in the
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1804binary packages of libxml, but you can find it in the tar source
Daniel Veillard402e8c82000-02-29 22:57:47 +0000[diff] [blame]1805distribution). Here is the sequence of callbacks that would be reported by
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]1806testSAX when parsing the example XML document shown earlier:</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1807<pre>SAX.setDocumentLocator()
1808SAX.startDocument()
1809SAX.getEntity(amp)
1810SAX.startElement(EXAMPLE, prop1='gnome is great', prop2='&amp;amp; linux too')
1811SAX.characters( , 3)
1812SAX.startElement(head)
1813SAX.characters( , 4)
1814SAX.startElement(title)
1815SAX.characters(Welcome to Gnome, 16)
1816SAX.endElement(title)
1817SAX.characters( , 3)
1818SAX.endElement(head)
1819SAX.characters( , 3)
1820SAX.startElement(chapter)
1821SAX.characters( , 4)
1822SAX.startElement(title)
1823SAX.characters(The Linux adventure, 19)
1824SAX.endElement(title)
1825SAX.characters( , 4)
1826SAX.startElement(p)
1827SAX.characters(bla bla bla ..., 15)
1828SAX.endElement(p)
1829SAX.characters( , 4)
1830SAX.startElement(image, href='linus.gif')
1831SAX.endElement(image)
1832SAX.characters( , 4)
1833SAX.startElement(p)
1834SAX.characters(..., 3)
1835SAX.endElement(p)
1836SAX.characters( , 3)
1837SAX.endElement(chapter)
1838SAX.characters( , 1)
1839SAX.endElement(EXAMPLE)
1840SAX.endDocument()</pre>
1841
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]1842<p>Most of the other interfaces of libxml are based on the DOM tree-building
1843facility, so nearly everything up to the end of this document presupposes the
1844use of the standard DOM tree build. Note that the DOM tree itself is built by
1845a set of registered default callbacks, without internal specific
1846interface.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]1847
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]1848<h2><a name="Validation">Validation &amp; DTDs</a></h2>
1849
1850<p>Table of Content:</p>
1851<ol>
1852 <li><a href="#General5">General overview</a></li>
1853 <li><a href="#definition">The definition</a></li>
1854 <li><a href="#Simple">Simple rules</a>
1855 <ol>
Daniel Veillard9c466822001-10-25 12:03:39 +0000[diff] [blame]1856 <li><a href="#reference">How to reference a DTD from a document</a></li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]1857 <li><a href="#Declaring">Declaring elements</a></li>
1858 <li><a href="#Declaring1">Declaring attributes</a></li>
1859 </ol>
1860 </li>
1861 <li><a href="#Some">Some examples</a></li>
1862 <li><a href="#validate">How to validate</a></li>
1863 <li><a href="#Other">Other resources</a></li>
1864</ol>
1865
1866<h3><a name="General5">General overview</a></h3>
1867
1868<p>Well what is validation and what is a DTD ?</p>
1869
1870<p>DTD is the acronym for Document Type Definition. This is a description of
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1871the content for a family of XML files. This is part of the XML 1.0
Daniel Veillardc0801af2002-05-28 16:28:42 +0000[diff] [blame]1872specification, and allows to describe and check that a given document
1873instance conforms to a set of rules detailing its structure and content.</p>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]1874
1875<p>Validation is the process of checking a document against a DTD (more
1876generally against a set of construction rules).</p>
1877
1878<p>The validation process and building DTDs are the two most difficult parts
1879of the XML life cycle. Briefly a DTD defines all the possibles element to be
1880found within your document, what is the formal shape of your document tree
1881(by defining the allowed content of an element, either text, a regular
1882expression for the allowed list of children, or mixed content i.e. both text
1883and children). The DTD also defines the allowed attributes for all elements
1884and the types of the attributes.</p>
1885
1886<h3><a name="definition1">The definition</a></h3>
1887
1888<p>The <a href="http://www.w3.org/TR/REC-xml">W3C XML Recommendation</a> (<a
1889href="http://www.xml.com/axml/axml.html">Tim Bray's annotated version of
1890Rev1</a>):</p>
1891<ul>
1892 <li><a href="http://www.w3.org/TR/REC-xml#elemdecls">Declaring
1893 elements</a></li>
1894 <li><a href="http://www.w3.org/TR/REC-xml#attdecls">Declaring
1895 attributes</a></li>
1896</ul>
1897
1898<p>(unfortunately) all this is inherited from the SGML world, the syntax is
1899ancient...</p>
1900
1901<h3><a name="Simple1">Simple rules</a></h3>
1902
1903<p>Writing DTD can be done in multiple ways, the rules to build them if you
1904need something fixed or something which can evolve over time can be radically
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1905different. Really complex DTD like DocBook ones are flexible but quite harder
1906to design. I will just focus on DTDs for a formats with a fixed simple
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]1907structure. It is just a set of basic rules, and definitely not exhaustive nor
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1908usable for complex DTD design.</p>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]1909
1910<h4><a name="reference1">How to reference a DTD from a document</a>:</h4>
1911
1912<p>Assuming the top element of the document is <code>spec</code> and the dtd
1913is placed in the file <code>mydtd</code> in the subdirectory
1914<code>dtds</code> of the directory from where the document were loaded:</p>
1915
1916<p><code>&lt;!DOCTYPE spec SYSTEM "dtds/mydtd"&gt;</code></p>
1917
1918<p>Notes:</p>
1919<ul>
1920 <li>the system string is actually an URI-Reference (as defined in <a
1921 href="http://www.ietf.org/rfc/rfc2396.txt">RFC 2396</a>) so you can use a
1922 full URL string indicating the location of your DTD on the Web, this is a
1923 really good thing to do if you want others to validate your document</li>
1924 <li>it is also possible to associate a <code>PUBLIC</code> identifier (a
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1925 magic string) so that the DTD is looked up in catalogs on the client side
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]1926 without having to locate it on the web</li>
1927 <li>a dtd contains a set of elements and attributes declarations, but they
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1928 don't define what the root of the document should be. This is explicitly
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]1929 told to the parser/validator as the first element of the
1930 <code>DOCTYPE</code> declaration.</li>
1931</ul>
1932
1933<h4><a name="Declaring2">Declaring elements</a>:</h4>
1934
1935<p>The following declares an element <code>spec</code>:</p>
1936
1937<p><code>&lt;!ELEMENT spec (front, body, back?)&gt;</code></p>
1938
1939<p>it also expresses that the spec element contains one <code>front</code>,
Daniel Veillardc0801af2002-05-28 16:28:42 +0000[diff] [blame]1940one <code>body</code> and one optional <code>back</code> children elements in
1941this order. The declaration of one element of the structure and its content
1942are done in a single declaration. Similarly the following declares
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]1943<code>div1</code> elements:</p>
1944
Daniel Veillard51737272002-01-23 23:10:38 +0000[diff] [blame]1945<p><code>&lt;!ELEMENT div1 (head, (p | list | note)*, div2?)&gt;</code></p>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]1946
1947<p>means div1 contains one <code>head</code> then a series of optional
1948<code>p</code>, <code>list</code>s and <code>note</code>s and then an
1949optional <code>div2</code>. And last but not least an element can contain
1950text:</p>
1951
1952<p><code>&lt;!ELEMENT b (#PCDATA)&gt;</code></p>
1953
1954<p><code>b</code> contains text or being of mixed content (text and elements
1955in no particular order):</p>
1956
1957<p><code>&lt;!ELEMENT p (#PCDATA|a|ul|b|i|em)*&gt;</code></p>
1958
1959<p><code>p </code>can contain text or <code>a</code>, <code>ul</code>,
1960<code>b</code>, <code>i </code>or <code>em</code> elements in no particular
1961order.</p>
1962
1963<h4><a name="Declaring1">Declaring attributes</a>:</h4>
1964
1965<p>again the attributes declaration includes their content definition:</p>
1966
1967<p><code>&lt;!ATTLIST termdef name CDATA #IMPLIED&gt;</code></p>
1968
1969<p>means that the element <code>termdef</code> can have a <code>name</code>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1970attribute containing text (<code>CDATA</code>) and which is optional
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]1971(<code>#IMPLIED</code>). The attribute value can also be defined within a
1972set:</p>
1973
1974<p><code>&lt;!ATTLIST list type (bullets|ordered|glossary)
1975"ordered"&gt;</code></p>
1976
1977<p>means <code>list</code> element have a <code>type</code> attribute with 3
1978allowed values "bullets", "ordered" or "glossary" and which default to
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]1979"ordered" if the attribute is not explicitly specified.</p>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]1980
1981<p>The content type of an attribute can be text (<code>CDATA</code>),
1982anchor/reference/references
1983(<code>ID</code>/<code>IDREF</code>/<code>IDREFS</code>), entity(ies)
1984(<code>ENTITY</code>/<code>ENTITIES</code>) or name(s)
1985(<code>NMTOKEN</code>/<code>NMTOKENS</code>). The following defines that a
1986<code>chapter</code> element can have an optional <code>id</code> attribute
1987of type <code>ID</code>, usable for reference from attribute of type
1988IDREF:</p>
1989
1990<p><code>&lt;!ATTLIST chapter id ID #IMPLIED&gt;</code></p>
1991
1992<p>The last value of an attribute definition can be <code>#REQUIRED
1993</code>meaning that the attribute has to be given, <code>#IMPLIED</code>
1994meaning that it is optional, or the default value (possibly prefixed by
1995<code>#FIXED</code> if it is the only allowed).</p>
1996
1997<p>Notes:</p>
1998<ul>
1999 <li>usually the attributes pertaining to a given element are declared in a
2000 single expression, but it is just a convention adopted by a lot of DTD
2001 writers:
2002 <pre>&lt;!ATTLIST termdef
2003 id ID #REQUIRED
2004 name CDATA #IMPLIED&gt;</pre>
2005 <p>The previous construct defines both <code>id</code> and
2006 <code>name</code> attributes for the element <code>termdef</code></p>
2007 </li>
2008</ul>
2009
2010<h3><a name="Some1">Some examples</a></h3>
2011
2012<p>The directory <code>test/valid/dtds/</code> in the libxml distribution
2013contains some complex DTD examples. The <code>test/valid/dia.xml</code>
2014example shows an XML file where the simple DTD is directly included within
2015the document.</p>
2016
2017<h3><a name="validate1">How to validate</a></h3>
2018
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]2019<p>The simplest is to use the xmllint program coming with libxml. The
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2020<code>--valid</code> option turn on validation of the files given as input,
2021for example the following validates a copy of the first revision of the XML
20221.0 specification:</p>
2023
2024<p><code>xmllint --valid --noout test/valid/REC-xml-19980210.xml</code></p>
2025
2026<p>the -- noout is used to not output the resulting tree.</p>
2027
2028<p>The <code>--dtdvalid dtd</code> allows to validate the document(s) against
2029a given DTD.</p>
2030
2031<p>Libxml exports an API to handle DTDs and validation, check the <a
2032href="http://xmlsoft.org/html/libxml-valid.html">associated
2033description</a>.</p>
2034
2035<h3><a name="Other1">Other resources</a></h3>
2036
2037<p>DTDs are as old as SGML. So there may be a number of examples on-line, I
2038will just list one for now, others pointers welcome:</p>
2039<ul>
2040 <li><a href="http://www.xml101.com:8081/dtd/">XML-101 DTD</a></li>
2041</ul>
2042
2043<p>I suggest looking at the examples found under test/valid/dtd and any of
2044the large number of books available on XML. The dia example in test/valid
2045should be both simple and complete enough to allow you to build your own.</p>
2046
2047<p></p>
2048
2049<h2><a name="Memory">Memory Management</a></h2>
2050
2051<p>Table of Content:</p>
2052<ol>
2053 <li><a href="#General3">General overview</a></li>
Daniel Veillard9c466822001-10-25 12:03:39 +0000[diff] [blame]2054 <li><a href="#setting">Setting libxml set of memory routines</a></li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2055 <li><a href="#cleanup">Cleaning up after parsing</a></li>
2056 <li><a href="#Debugging">Debugging routines</a></li>
2057 <li><a href="#General4">General memory requirements</a></li>
2058</ol>
2059
2060<h3><a name="General3">General overview</a></h3>
2061
2062<p>The module <code><a
2063href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlmemory.h</a></code>
2064provides the interfaces to the libxml memory system:</p>
2065<ul>
2066 <li>libxml does not use the libc memory allocator directly but xmlFree(),
2067 xmlMalloc() and xmlRealloc()</li>
2068 <li>those routines can be reallocated to a specific set of routine, by
2069 default the libc ones i.e. free(), malloc() and realloc()</li>
2070 <li>the xmlmemory.c module includes a set of debugging routine</li>
2071</ul>
2072
2073<h3><a name="setting">Setting libxml set of memory routines</a></h3>
2074
2075<p>It is sometimes useful to not use the default memory allocator, either for
2076debugging, analysis or to implement a specific behaviour on memory management
2077(like on embedded systems). Two function calls are available to do so:</p>
2078<ul>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]2079 <li><a href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlMemGet
2080 ()</a> which return the current set of functions in use by the parser</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2081 <li><a
2082 href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlMemSetup()</a>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]2083 which allow to set up a new set of memory allocation functions</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2084</ul>
2085
2086<p>Of course a call to xmlMemSetup() should probably be done before calling
2087any other libxml routines (unless you are sure your allocations routines are
2088compatibles).</p>
2089
2090<h3><a name="cleanup">Cleaning up after parsing</a></h3>
2091
2092<p>Libxml is not stateless, there is a few set of memory structures needing
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]2093allocation before the parser is fully functional (some encoding structures
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2094for example). This also mean that once parsing is finished there is a tiny
2095amount of memory (a few hundred bytes) which can be recollected if you don't
2096reuse the parser immediately:</p>
2097<ul>
2098 <li><a href="http://xmlsoft.org/html/libxml-parser.html">xmlCleanupParser
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]2099 ()</a> is a centralized routine to free the parsing states. Note that it
2100 won't deallocate any produced tree if any (use the xmlFreeDoc() and
2101 related routines for this).</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2102 <li><a href="http://xmlsoft.org/html/libxml-parser.html">xmlInitParser
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]2103 ()</a> is the dual routine allowing to preallocate the parsing state
2104 which can be useful for example to avoid initialization reentrancy
2105 problems when using libxml in multithreaded applications</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2106</ul>
2107
2108<p>Generally xmlCleanupParser() is safe, if needed the state will be rebuild
2109at the next invocation of parser routines, but be careful of the consequences
2110in multithreaded applications.</p>
2111
2112<h3><a name="Debugging">Debugging routines</a></h3>
2113
2114<p>When configured using --with-mem-debug flag (off by default), libxml uses
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]2115a set of memory allocation debugging routines keeping track of all allocated
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2116blocks and the location in the code where the routine was called. A couple of
2117other debugging routines allow to dump the memory allocated infos to a file
2118or call a specific routine when a given block number is allocated:</p>
2119<ul>
2120 <li><a
2121 href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlMallocLoc()</a>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]2122 <a
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2123 href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlReallocLoc()</a>
2124 and <a
2125 href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlMemStrdupLoc()</a>
2126 are the memory debugging replacement allocation routines</li>
2127 <li><a href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlMemoryDump
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]2128 ()</a> dumps all the informations about the allocated memory block lefts
2129 in the <code>.memdump</code> file</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2130</ul>
2131
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]2132<p>When developing libxml memory debug is enabled, the tests programs call
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2133xmlMemoryDump () and the "make test" regression tests will check for any
2134memory leak during the full regression test sequence, this helps a lot
2135ensuring that libxml does not leak memory and bullet proof memory
2136allocations use (some libc implementations are known to be far too permissive
2137resulting in major portability problems!).</p>
2138
2139<p>If the .memdump reports a leak, it displays the allocation function and
2140also tries to give some informations about the content and structure of the
2141allocated blocks left. This is sufficient in most cases to find the culprit,
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]2142but not always. Assuming the allocation problem is reproducible, it is
2143possible to find more easily:</p>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2144<ol>
2145 <li>write down the block number xxxx not allocated</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]2146 <li>export the environment variable XML_MEM_BREAKPOINT=xxxx , the easiest
Daniel Veillard75794822002-04-11 16:24:32 +0000[diff] [blame]2147 when using GDB is to simply give the command
2148 <p><code>set environment XML_MEM_BREAKPOINT xxxx</code></p>
2149 <p>before running the program.</p>
2150 </li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2151 <li>run the program under a debugger and set a breakpoint on
2152 xmlMallocBreakpoint() a specific function called when this precise block
2153 is allocated</li>
2154 <li>when the breakpoint is reached you can then do a fine analysis of the
2155 allocation an step to see the condition resulting in the missing
2156 deallocation.</li>
2157</ol>
2158
2159<p>I used to use a commercial tool to debug libxml memory problems but after
2160noticing that it was not detecting memory leaks that simple mechanism was
Daniel Veillard75794822002-04-11 16:24:32 +0000[diff] [blame]2161used and proved extremely efficient until now. Lately I have also used <a
2162href="http://developer.kde.org/~sewardj/">valgrind</a> with quite some
2163success, it is tied to the i386 architecture since it works by emulating the
2164processor and instruction set, it is slow but extremely efficient, i.e. it
2165spot memory usage errors in a very precise way.</p>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2166
2167<h3><a name="General4">General memory requirements</a></h3>
2168
2169<p>How much libxml memory require ? It's hard to tell in average it depends
2170of a number of things:</p>
2171<ul>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]2172 <li>the parser itself should work in a fixed amount of memory, except for
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2173 information maintained about the stacks of names and entities locations.
2174 The I/O and encoding handlers will probably account for a few KBytes.
2175 This is true for both the XML and HTML parser (though the HTML parser
2176 need more state).</li>
2177 <li>If you are generating the DOM tree then memory requirements will grow
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]2178 nearly linear with the size of the data. In general for a balanced
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2179 textual document the internal memory requirement is about 4 times the
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]2180 size of the UTF8 serialization of this document (example the XML-1.0
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2181 recommendation is a bit more of 150KBytes and takes 650KBytes of main
2182 memory when parsed). Validation will add a amount of memory required for
2183 maintaining the external Dtd state which should be linear with the
2184 complexity of the content model defined by the Dtd</li>
2185 <li>If you don't care about the advanced features of libxml like
2186 validation, DOM, XPath or XPointer, but really need to work fixed memory
2187 requirements, then the SAX interface should be used.</li>
2188</ul>
2189
2190<p></p>
2191
2192<h2><a name="Encodings">Encodings support</a></h2>
2193
2194<p>Table of Content:</p>
2195<ol>
2196 <li><a href="encoding.html#What">What does internationalization support
2197 mean ?</a></li>
2198 <li><a href="encoding.html#internal">The internal encoding, how and
2199 why</a></li>
2200 <li><a href="encoding.html#implemente">How is it implemented ?</a></li>
2201 <li><a href="encoding.html#Default">Default supported encodings</a></li>
2202 <li><a href="encoding.html#extend">How to extend the existing
2203 support</a></li>
2204</ol>
2205
2206<h3><a name="What">What does internationalization support mean ?</a></h3>
2207
2208<p>XML was designed from the start to allow the support of any character set
2209by using Unicode. Any conformant XML parser has to support the UTF-8 and
2210UTF-16 default encodings which can both express the full unicode ranges. UTF8
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]2211is a variable length encoding whose greatest points are to reuse the same
2212encoding for ASCII and to save space for Western encodings, but it is a bit
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2213more complex to handle in practice. UTF-16 use 2 bytes per characters (and
2214sometimes combines two pairs), it makes implementation easier, but looks a
2215bit overkill for Western languages encoding. Moreover the XML specification
2216allows document to be encoded in other encodings at the condition that they
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]2217are clearly labeled as such. For example the following is a wellformed XML
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2218document encoded in ISO-8859 1 and using accentuated letter that we French
2219likes for both markup and content:</p>
2220<pre>&lt;?xml version="1.0" encoding="ISO-8859-1"?&gt;
2221&lt;très&gt;là&lt;/très&gt;</pre>
2222
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]2223<p>Having internationalization support in libxml means the following:</p>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2224<ul>
2225 <li>the document is properly parsed</li>
2226 <li>informations about it's encoding are saved</li>
2227 <li>it can be modified</li>
2228 <li>it can be saved in its original encoding</li>
2229 <li>it can also be saved in another encoding supported by libxml (for
2230 example straight UTF8 or even an ASCII form)</li>
2231</ul>
2232
2233<p>Another very important point is that the whole libxml API, with the
2234exception of a few routines to read with a specific encoding or save to a
2235specific encoding, is completely agnostic about the original encoding of the
2236document.</p>
2237
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]2238<p>It should be noted too that the HTML parser embedded in libxml now obey
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2239the same rules too, the following document will be (as of 2.2.2) handled in
2240an internationalized fashion by libxml too:</p>
2241<pre>&lt;!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"
2242 "http://www.w3.org/TR/REC-html40/loose.dtd"&gt;
2243&lt;html lang="fr"&gt;
2244&lt;head&gt;
2245 &lt;META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=ISO-8859-1"&gt;
2246&lt;/head&gt;
2247&lt;body&gt;
2248&lt;p&gt;W3C crée des standards pour le Web.&lt;/body&gt;
2249&lt;/html&gt;</pre>
2250
2251<h3><a name="internal">The internal encoding, how and why</a></h3>
2252
2253<p>One of the core decision was to force all documents to be converted to a
2254default internal encoding, and that encoding to be UTF-8, here are the
2255rationale for those choices:</p>
2256<ul>
2257 <li>keeping the native encoding in the internal form would force the libxml
2258 users (or the code associated) to be fully aware of the encoding of the
2259 original document, for examples when adding a text node to a document,
2260 the content would have to be provided in the document encoding, i.e. the
2261 client code would have to check it before hand, make sure it's conformant
2262 to the encoding, etc ... Very hard in practice, though in some specific
2263 cases this may make sense.</li>
2264 <li>the second decision was which encoding. From the XML spec only UTF8 and
2265 UTF16 really makes sense as being the two only encodings for which there
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]2266 is mandatory support. UCS-4 (32 bits fixed size encoding) could be
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2267 considered an intelligent choice too since it's a direct Unicode mapping
2268 support. I selected UTF-8 on the basis of efficiency and compatibility
2269 with surrounding software:
2270 <ul>
2271 <li>UTF-8 while a bit more complex to convert from/to (i.e. slightly
2272 more costly to import and export CPU wise) is also far more compact
2273 than UTF-16 (and UCS-4) for a majority of the documents I see it used
2274 for right now (RPM RDF catalogs, advogato data, various configuration
2275 file formats, etc.) and the key point for today's computer
2276 architecture is efficient uses of caches. If one nearly double the
2277 memory requirement to store the same amount of data, this will trash
2278 caches (main memory/external caches/internal caches) and my take is
2279 that this harms the system far more than the CPU requirements needed
2280 for the conversion to UTF-8</li>
2281 <li>Most of libxml version 1 users were using it with straight ASCII
2282 most of the time, doing the conversion with an internal encoding
2283 requiring all their code to be rewritten was a serious show-stopper
2284 for using UTF-16 or UCS-4.</li>
2285 <li>UTF-8 is being used as the de-facto internal encoding standard for
2286 related code like the <a href="http://www.pango.org/">pango</a>
2287 upcoming Gnome text widget, and a lot of Unix code (yep another place
2288 where Unix programmer base takes a different approach from Microsoft
2289 - they are using UTF-16)</li>
2290 </ul>
2291 </li>
2292</ul>
2293
2294<p>What does this mean in practice for the libxml user:</p>
2295<ul>
2296 <li>xmlChar, the libxml data type is a byte, those bytes must be assembled
2297 as UTF-8 valid strings. The proper way to terminate an xmlChar * string
2298 is simply to append 0 byte, as usual.</li>
2299 <li>One just need to make sure that when using chars outside the ASCII set,
2300 the values has been properly converted to UTF-8</li>
2301</ul>
2302
2303<h3><a name="implemente">How is it implemented ?</a></h3>
2304
2305<p>Let's describe how all this works within libxml, basically the I18N
2306(internationalization) support get triggered only during I/O operation, i.e.
2307when reading a document or saving one. Let's look first at the reading
2308sequence:</p>
2309<ol>
2310 <li>when a document is processed, we usually don't know the encoding, a
2311 simple heuristic allows to detect UTF-18 and UCS-4 from whose where the
2312 ASCII range (0-0x7F) maps with ASCII</li>
2313 <li>the xml declaration if available is parsed, including the encoding
2314 declaration. At that point, if the autodetected encoding is different
2315 from the one declared a call to xmlSwitchEncoding() is issued.</li>
2316 <li>If there is no encoding declaration, then the input has to be in either
2317 UTF-8 or UTF-16, if it is not then at some point when processing the
2318 input, the converter/checker of UTF-8 form will raise an encoding error.
2319 You may end-up with a garbled document, or no document at all ! Example:
2320 <pre>~/XML -&gt; ./xmllint err.xml
2321err.xml:1: error: Input is not proper UTF-8, indicate encoding !
2322&lt;très&gt;là&lt;/très&gt;
2323 ^
2324err.xml:1: error: Bytes: 0xE8 0x73 0x3E 0x6C
2325&lt;très&gt;là&lt;/très&gt;
2326 ^</pre>
2327 </li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]2328 <li>xmlSwitchEncoding() does an encoding name lookup, canonicalize it, and
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2329 then search the default registered encoding converters for that encoding.
2330 If it's not within the default set and iconv() support has been compiled
2331 it, it will ask iconv for such an encoder. If this fails then the parser
2332 will report an error and stops processing:
2333 <pre>~/XML -&gt; ./xmllint err2.xml
2334err2.xml:1: error: Unsupported encoding UnsupportedEnc
2335&lt;?xml version="1.0" encoding="UnsupportedEnc"?&gt;
2336 ^</pre>
2337 </li>
Daniel Veillard46c5c1d2002-05-20 07:15:54 +0000[diff] [blame]2338 <li>From that point the encoder processes progressively the input (it is
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2339 plugged as a front-end to the I/O module) for that entity. It captures
2340 and convert on-the-fly the document to be parsed to UTF-8. The parser
2341 itself just does UTF-8 checking of this input and process it
2342 transparently. The only difference is that the encoding information has
2343 been added to the parsing context (more precisely to the input
2344 corresponding to this entity).</li>
2345 <li>The result (when using DOM) is an internal form completely in UTF-8
2346 with just an encoding information on the document node.</li>
2347</ol>
2348
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]2349<p>Ok then what happens when saving the document (assuming you
2350collected/built an xmlDoc DOM like structure) ? It depends on the function
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2351called, xmlSaveFile() will just try to save in the original encoding, while
2352xmlSaveFileTo() and xmlSaveFileEnc() can optionally save to a given
2353encoding:</p>
2354<ol>
2355 <li>if no encoding is given, libxml will look for an encoding value
2356 associated to the document and if it exists will try to save to that
2357 encoding,
2358 <p>otherwise everything is written in the internal form, i.e. UTF-8</p>
2359 </li>
2360 <li>so if an encoding was specified, either at the API level or on the
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]2361 document, libxml will again canonicalize the encoding name, lookup for a
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2362 converter in the registered set or through iconv. If not found the
2363 function will return an error code</li>
2364 <li>the converter is placed before the I/O buffer layer, as another kind of
2365 buffer, then libxml will simply push the UTF-8 serialization to through
2366 that buffer, which will then progressively be converted and pushed onto
2367 the I/O layer.</li>
2368 <li>It is possible that the converter code fails on some input, for example
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]2369 trying to push an UTF-8 encoded Chinese character through the UTF-8 to
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2370 ISO-8859-1 converter won't work. Since the encoders are progressive they
2371 will just report the error and the number of bytes converted, at that
2372 point libxml will decode the offending character, remove it from the
2373 buffer and replace it with the associated charRef encoding &amp;#123; and
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]2374 resume the conversion. This guarantees that any document will be saved
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2375 without losses (except for markup names where this is not legal, this is
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]2376 a problem in the current version, in practice avoid using non-ascii
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2377 characters for tags or attributes names @@). A special "ascii" encoding
2378 name is used to save documents to a pure ascii form can be used when
2379 portability is really crucial</li>
2380</ol>
2381
2382<p>Here is a few examples based on the same test document:</p>
2383<pre>~/XML -&gt; ./xmllint isolat1
2384&lt;?xml version="1.0" encoding="ISO-8859-1"?&gt;
2385&lt;très&gt;là&lt;/très&gt;
2386~/XML -&gt; ./xmllint --encode UTF-8 isolat1
2387&lt;?xml version="1.0" encoding="UTF-8"?&gt;
2388&lt;très&gt;là  &lt;/très&gt;
2389~/XML -&gt; </pre>
2390
2391<p>The same processing is applied (and reuse most of the code) for HTML I18N
2392processing. Looking up and modifying the content encoding is a bit more
2393difficult since it is located in a &lt;meta&gt; tag under the &lt;head&gt;,
2394so a couple of functions htmlGetMetaEncoding() and htmlSetMetaEncoding() have
2395been provided. The parser also attempts to switch encoding on the fly when
2396detecting such a tag on input. Except for that the processing is the same
2397(and again reuses the same code).</p>
2398
2399<h3><a name="Default">Default supported encodings</a></h3>
2400
2401<p>libxml has a set of default converters for the following encodings
2402(located in encoding.c):</p>
2403<ol>
2404 <li>UTF-8 is supported by default (null handlers)</li>
2405 <li>UTF-16, both little and big endian</li>
2406 <li>ISO-Latin-1 (ISO-8859-1) covering most western languages</li>
2407 <li>ASCII, useful mostly for saving</li>
2408 <li>HTML, a specific handler for the conversion of UTF-8 to ASCII with HTML
2409 predefined entities like &amp;copy; for the Copyright sign.</li>
2410</ol>
2411
Daniel Veillardc0801af2002-05-28 16:28:42 +0000[diff] [blame]2412<p>More over when compiled on an Unix platform with iconv support the full
2413set of encodings supported by iconv can be instantly be used by libxml. On a
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2414linux machine with glibc-2.1 the list of supported encodings and aliases fill
24153 full pages, and include UCS-4, the full set of ISO-Latin encodings, and the
2416various Japanese ones.</p>
2417
2418<h4>Encoding aliases</h4>
2419
2420<p>From 2.2.3, libxml has support to register encoding names aliases. The
2421goal is to be able to parse document whose encoding is supported but where
2422the name differs (for example from the default set of names accepted by
2423iconv). The following functions allow to register and handle new aliases for
2424existing encodings. Once registered libxml will automatically lookup the
2425aliases when handling a document:</p>
2426<ul>
2427 <li>int xmlAddEncodingAlias(const char *name, const char *alias);</li>
2428 <li>int xmlDelEncodingAlias(const char *alias);</li>
2429 <li>const char * xmlGetEncodingAlias(const char *alias);</li>
2430 <li>void xmlCleanupEncodingAliases(void);</li>
2431</ul>
2432
2433<h3><a name="extend">How to extend the existing support</a></h3>
2434
2435<p>Well adding support for new encoding, or overriding one of the encoders
2436(assuming it is buggy) should not be hard, just write an input and output
2437conversion routines to/from UTF-8, and register them using
2438xmlNewCharEncodingHandler(name, xxxToUTF8, UTF8Toxxx), and they will be
2439called automatically if the parser(s) encounter such an encoding name
2440(register it uppercase, this will help). The description of the encoders,
2441their arguments and expected return values are described in the encoding.h
2442header.</p>
2443
2444<p>A quick note on the topic of subverting the parser to use a different
2445internal encoding than UTF-8, in some case people will absolutely want to
2446keep the internal encoding different, I think it's still possible (but the
2447encoding must be compliant with ASCII on the same subrange) though I didn't
2448tried it. The key is to override the default conversion routines (by
2449registering null encoders/decoders for your charsets), and bypass the UTF-8
2450checking of the parser by setting the parser context charset
2451(ctxt-&gt;charset) to something different than XML_CHAR_ENCODING_UTF8, but
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]2452there is no guarantee that this will work. You may also have some troubles
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2453saving back.</p>
2454
2455<p>Basically proper I18N support is important, this requires at least
2456libxml-2.0.0, but a lot of features and corrections are really available only
2457starting 2.2.</p>
2458
2459<h2><a name="IO">I/O Interfaces</a></h2>
2460
2461<p>Table of Content:</p>
2462<ol>
2463 <li><a href="#General1">General overview</a></li>
2464 <li><a href="#basic">The basic buffer type</a></li>
2465 <li><a href="#Input">Input I/O handlers</a></li>
2466 <li><a href="#Output">Output I/O handlers</a></li>
2467 <li><a href="#entities">The entities loader</a></li>
2468 <li><a href="#Example2">Example of customized I/O</a></li>
2469</ol>
2470
2471<h3><a name="General1">General overview</a></h3>
2472
2473<p>The module <code><a
2474href="http://xmlsoft.org/html/libxml-xmlio.html">xmlIO.h</a></code> provides
2475the interfaces to the libxml I/O system. This consists of 4 main parts:</p>
2476<ul>
2477 <li>Entities loader, this is a routine which tries to fetch the entities
2478 (files) based on their PUBLIC and SYSTEM identifiers. The default loader
2479 don't look at the public identifier since libxml do not maintain a
2480 catalog. You can redefine you own entity loader by using
2481 <code>xmlGetExternalEntityLoader()</code> and
Daniel Veillard9c466822001-10-25 12:03:39 +0000[diff] [blame]2482 <code>xmlSetExternalEntityLoader()</code>. <a href="#entities">Check the
2483 example</a>.</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2484 <li>Input I/O buffers which are a commodity structure used by the parser(s)
2485 input layer to handle fetching the informations to feed the parser. This
2486 provides buffering and is also a placeholder where the encoding
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]2487 converters to UTF8 are piggy-backed.</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2488 <li>Output I/O buffers are similar to the Input ones and fulfill similar
2489 task but when generating a serialization from a tree.</li>
2490 <li>A mechanism to register sets of I/O callbacks and associate them with
2491 specific naming schemes like the protocol part of the URIs.
2492 <p>This affect the default I/O operations and allows to use specific I/O
2493 handlers for certain names.</p>
2494 </li>
2495</ul>
2496
2497<p>The general mechanism used when loading http://rpmfind.net/xml.html for
2498example in the HTML parser is the following:</p>
2499<ol>
2500 <li>The default entity loader calls <code>xmlNewInputFromFile()</code> with
2501 the parsing context and the URI string.</li>
2502 <li>the URI string is checked against the existing registered handlers
2503 using their match() callback function, if the HTTP module was compiled
2504 in, it is registered and its match() function will succeeds</li>
2505 <li>the open() function of the handler is called and if successful will
2506 return an I/O Input buffer</li>
2507 <li>the parser will the start reading from this buffer and progressively
2508 fetch information from the resource, calling the read() function of the
2509 handler until the resource is exhausted</li>
2510 <li>if an encoding change is detected it will be installed on the input
2511 buffer, providing buffering and efficient use of the conversion
2512 routines</li>
2513 <li>once the parser has finished, the close() function of the handler is
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]2514 called once and the Input buffer and associated resources are
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2515 deallocated.</li>
2516</ol>
2517
2518<p>The user defined callbacks are checked first to allow overriding of the
2519default libxml I/O routines.</p>
2520
2521<h3><a name="basic">The basic buffer type</a></h3>
2522
2523<p>All the buffer manipulation handling is done using the
2524<code>xmlBuffer</code> type define in <code><a
2525href="http://xmlsoft.org/html/libxml-tree.html">tree.h</a> </code>which is a
2526resizable memory buffer. The buffer allocation strategy can be selected to be
2527either best-fit or use an exponential doubling one (CPU vs. memory use
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]2528trade-off). The values are <code>XML_BUFFER_ALLOC_EXACT</code> and
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2529<code>XML_BUFFER_ALLOC_DOUBLEIT</code>, and can be set individually or on a
2530system wide basis using <code>xmlBufferSetAllocationScheme()</code>. A number
2531of functions allows to manipulate buffers with names starting with the
2532<code>xmlBuffer...</code> prefix.</p>
2533
2534<h3><a name="Input">Input I/O handlers</a></h3>
2535
2536<p>An Input I/O handler is a simple structure
2537<code>xmlParserInputBuffer</code> containing a context associated to the
2538resource (file descriptor, or pointer to a protocol handler), the read() and
2539close() callbacks to use and an xmlBuffer. And extra xmlBuffer and a charset
2540encoding handler are also present to support charset conversion when
2541needed.</p>
2542
2543<h3><a name="Output">Output I/O handlers</a></h3>
2544
2545<p>An Output handler <code>xmlOutputBuffer</code> is completely similar to an
2546Input one except the callbacks are write() and close().</p>
2547
2548<h3><a name="entities">The entities loader</a></h3>
2549
2550<p>The entity loader resolves requests for new entities and create inputs for
2551the parser. Creating an input from a filename or an URI string is done
2552through the xmlNewInputFromFile() routine. The default entity loader do not
2553handle the PUBLIC identifier associated with an entity (if any). So it just
2554calls xmlNewInputFromFile() with the SYSTEM identifier (which is mandatory in
2555XML).</p>
2556
2557<p>If you want to hook up a catalog mechanism then you simply need to
2558override the default entity loader, here is an example:</p>
2559<pre>#include &lt;libxml/xmlIO.h&gt;
2560
2561xmlExternalEntityLoader defaultLoader = NULL;
2562
2563xmlParserInputPtr
2564xmlMyExternalEntityLoader(const char *URL, const char *ID,
2565 xmlParserCtxtPtr ctxt) {
2566 xmlParserInputPtr ret;
2567 const char *fileID = NULL;
2568 /* lookup for the fileID depending on ID */
2569
2570 ret = xmlNewInputFromFile(ctxt, fileID);
2571 if (ret != NULL)
2572 return(ret);
2573 if (defaultLoader != NULL)
2574 ret = defaultLoader(URL, ID, ctxt);
2575 return(ret);
2576}
2577
2578int main(..) {
2579 ...
2580
2581 /*
2582 * Install our own entity loader
2583 */
2584 defaultLoader = xmlGetExternalEntityLoader();
2585 xmlSetExternalEntityLoader(xmlMyExternalEntityLoader);
2586
2587 ...
2588}</pre>
2589
2590<h3><a name="Example2">Example of customized I/O</a></h3>
2591
2592<p>This example come from <a href="http://xmlsoft.org/messages/0708.html">a
2593real use case</a>, xmlDocDump() closes the FILE * passed by the application
2594and this was a problem. The <a
2595href="http://xmlsoft.org/messages/0711.html">solution</a> was to redefine a
2596new output handler with the closing call deactivated:</p>
2597<ol>
Daniel Veillardc0801af2002-05-28 16:28:42 +0000[diff] [blame]2598 <li>First define a new I/O output allocator where the output don't close
2599 the file:
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2600 <pre>xmlOutputBufferPtr
2601xmlOutputBufferCreateOwn(FILE *file, xmlCharEncodingHandlerPtr encoder) {
2602    xmlOutputBufferPtr ret;
2603    
2604    if (xmlOutputCallbackInitialized == 0)
2605        xmlRegisterDefaultOutputCallbacks();
2606
2607    if (file == NULL) return(NULL);
2608    ret = xmlAllocOutputBuffer(encoder);
2609    if (ret != NULL) {
2610        ret-&gt;context = file;
2611        ret-&gt;writecallback = xmlFileWrite;
2612        ret-&gt;closecallback = NULL; /* No close callback */
2613    }
2614    return(ret); <br>
Daniel Veillard1eb24242002-03-18 11:33:03 +0000[diff] [blame]2615
Daniel Veillard34ce8be2002-03-18 19:37:11 +0000[diff] [blame]2616
2617
Daniel Veillard19274092002-03-25 16:48:03 +0000[diff] [blame]2618
Daniel Veillardb2fb8ed2002-04-01 09:33:12 +0000[diff] [blame]2619
Daniel Veillard75794822002-04-11 16:24:32 +0000[diff] [blame]2620
Daniel Veillarda7084cd2002-04-15 17:12:47 +0000[diff] [blame]2621
Daniel Veillard0bfbb422002-04-26 09:21:45 +0000[diff] [blame]2622
Daniel Veillard93d3a472002-04-26 14:04:55 +0000[diff] [blame]2623
Daniel Veillardcf27f7c2002-04-30 07:12:39 +0000[diff] [blame]2624
Daniel Veillarde6d8e202002-05-02 06:11:10 +0000[diff] [blame]2625
Daniel Veillard9b6fd302002-05-13 12:06:47 +0000[diff] [blame]2626
Daniel Veillardc0801af2002-05-28 16:28:42 +0000[diff] [blame]2627
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2628} </pre>
2629 </li>
2630 <li>And then use it to save the document:
2631 <pre>FILE *f;
2632xmlOutputBufferPtr output;
2633xmlDocPtr doc;
2634int res;
2635
2636f = ...
2637doc = ....
2638
2639output = xmlOutputBufferCreateOwn(f, NULL);
2640res = xmlSaveFileTo(output, doc, NULL);
2641 </pre>
2642 </li>
2643</ol>
2644
2645<h2><a name="Catalog">Catalog support</a></h2>
2646
2647<p>Table of Content:</p>
2648<ol>
2649 <li><a href="General2">General overview</a></li>
2650 <li><a href="#definition">The definition</a></li>
2651 <li><a href="#Simple">Using catalogs</a></li>
2652 <li><a href="#Some">Some examples</a></li>
2653 <li><a href="#reference">How to tune catalog usage</a></li>
2654 <li><a href="#validate">How to debug catalog processing</a></li>
2655 <li><a href="#Declaring">How to create and maintain catalogs</a></li>
2656 <li><a href="#implemento">The implementor corner quick review of the
2657 API</a></li>
2658 <li><a href="#Other">Other resources</a></li>
2659</ol>
2660
2661<h3><a name="General2">General overview</a></h3>
2662
2663<p>What is a catalog? Basically it's a lookup mechanism used when an entity
2664(a file or a remote resource) references another entity. The catalog lookup
2665is inserted between the moment the reference is recognized by the software
2666(XML parser, stylesheet processing, or even images referenced for inclusion
2667in a rendering) and the time where loading that resource is actually
2668started.</p>
2669
2670<p>It is basically used for 3 things:</p>
2671<ul>
2672 <li>mapping from "logical" names, the public identifiers and a more
2673 concrete name usable for download (and URI). For example it can associate
2674 the logical name
2675 <p>"-//OASIS//DTD DocBook XML V4.1.2//EN"</p>
2676 <p>of the DocBook 4.1.2 XML DTD with the actual URL where it can be
2677 downloaded</p>
2678 <p>http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd</p>
2679 </li>
2680 <li>remapping from a given URL to another one, like an HTTP indirection
2681 saying that
2682 <p>"http://www.oasis-open.org/committes/tr.xsl"</p>
2683 <p>should really be looked at</p>
2684 <p>"http://www.oasis-open.org/committes/entity/stylesheets/base/tr.xsl"</p>
2685 </li>
2686 <li>providing a local cache mechanism allowing to load the entities
2687 associated to public identifiers or remote resources, this is a really
2688 important feature for any significant deployment of XML or SGML since it
2689 allows to avoid the aleas and delays associated to fetching remote
2690 resources.</li>
2691</ul>
2692
2693<h3><a name="definition">The definitions</a></h3>
2694
2695<p>Libxml, as of 2.4.3 implements 2 kind of catalogs:</p>
2696<ul>
2697 <li>the older SGML catalogs, the official spec is SGML Open Technical
2698 Resolution TR9401:1997, but is better understood by reading <a
2699 href="http://www.jclark.com/sp/catalog.htm">the SP Catalog page</a> from
2700 James Clark. This is relatively old and not the preferred mode of
2701 operation of libxml.</li>
2702 <li><a href="http://www.oasis-open.org/committees/entity/spec.html">XML
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]2703 Catalogs</a> is far more flexible, more recent, uses an XML syntax and
2704 should scale quite better. This is the default option of libxml.</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]2705</ul>
2706
2707<p></p>
2708
2709<h3><a name="Simple">Using catalog</a></h3>
2710
2711<p>In a normal environment libxml will by default check the presence of a
2712catalog in /etc/xml/catalog, and assuming it has been correctly populated,
2713the processing is completely transparent to the document user. To take a
2714concrete example, suppose you are authoring a DocBook document, this one
2715starts with the following DOCTYPE definition:</p>
2716<pre>&lt;?xml version='1.0'?&gt;
2717&lt;!DOCTYPE book PUBLIC "-//Norman Walsh//DTD DocBk XML V3.1.4//EN"
2718 "http://nwalsh.com/docbook/xml/3.1.4/db3xml.dtd"&gt;</pre>
2719
2720<p>When validating the document with libxml, the catalog will be
2721automatically consulted to lookup the public identifier "-//Norman Walsh//DTD
2722DocBk XML V3.1.4//EN" and the system identifier
2723"http://nwalsh.com/docbook/xml/3.1.4/db3xml.dtd", and if these entities have
2724been installed on your system and the catalogs actually point to them, libxml
2725will fetch them from the local disk.</p>
2726
2727<p style="font-size: 10pt"><strong>Note</strong>: Really don't use this
2728DOCTYPE example it's a really old version, but is fine as an example.</p>
2729
2730<p>Libxml will check the catalog each time that it is requested to load an
2731entity, this includes DTD, external parsed entities, stylesheets, etc ... If
2732your system is correctly configured all the authoring phase and processing
2733should use only local files, even if your document stays portable because it
2734uses the canonical public and system ID, referencing the remote document.</p>
2735
2736<h3><a name="Some">Some examples:</a></h3>
2737
2738<p>Here is a couple of fragments from XML Catalogs used in libxml early
2739regression tests in <code>test/catalogs</code> :</p>
2740<pre>&lt;?xml version="1.0"?&gt;
2741&lt;!DOCTYPE catalog PUBLIC
2742 "-//OASIS//DTD Entity Resolution XML Catalog V1.0//EN"
2743 "http://www.oasis-open.org/committees/entity/release/1.0/catalog.dtd"&gt;
2744&lt;catalog xmlns="urn:oasis:names:tc:entity:xmlns:xml:catalog"&gt;
2745 &lt;public publicId="-//OASIS//DTD DocBook XML V4.1.2//EN"
2746 uri="http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd"/&gt;
2747...</pre>
2748
2749<p>This is the beginning of a catalog for DocBook 4.1.2, XML Catalogs are
2750written in XML, there is a specific namespace for catalog elements
2751"urn:oasis:names:tc:entity:xmlns:xml:catalog". The first entry in this
2752catalog is a <code>public</code> mapping it allows to associate a Public
2753Identifier with an URI.</p>
2754<pre>...
2755 &lt;rewriteSystem systemIdStartString="http://www.oasis-open.org/docbook/"
2756 rewritePrefix="file:///usr/share/xml/docbook/"/&gt;
2757...</pre>
2758
2759<p>A <code>rewriteSystem</code> is a very powerful instruction, it says that
2760any URI starting with a given prefix should be looked at another URI
2761constructed by replacing the prefix with an new one. In effect this acts like
2762a cache system for a full area of the Web. In practice it is extremely useful
2763with a file prefix if you have installed a copy of those resources on your
2764local system.</p>
2765<pre>...
2766&lt;delegatePublic publicIdStartString="-//OASIS//DTD XML Catalog //"
2767 catalog="file:///usr/share/xml/docbook.xml"/&gt;
2768&lt;delegatePublic publicIdStartString="-//OASIS//ENTITIES DocBook XML"
2769 catalog="file:///usr/share/xml/docbook.xml"/&gt;
2770&lt;delegatePublic publicIdStartString="-//OASIS//DTD DocBook XML"
2771 catalog="file:///usr/share/xml/docbook.xml"/&gt;
2772&lt;delegateSystem systemIdStartString="http://www.oasis-open.org/docbook/"
2773 catalog="file:///usr/share/xml/docbook.xml"/&gt;
2774&lt;delegateURI uriStartString="http://www.oasis-open.org/docbook/"
2775 catalog="file:///usr/share/xml/docbook.xml"/&gt;
2776...</pre>
2777
2778<p>Delegation is the core features which allows to build a tree of catalogs,
2779easier to maintain than a single catalog, based on Public Identifier, System
2780Identifier or URI prefixes it instructs the catalog software to look up
2781entries in another resource. This feature allow to build hierarchies of
2782catalogs, the set of entries presented should be sufficient to redirect the
2783resolution of all DocBook references to the specific catalog in
2784<code>/usr/share/xml/docbook.xml</code> this one in turn could delegate all
2785references for DocBook 4.2.1 to a specific catalog installed at the same time
2786as the DocBook resources on the local machine.</p>
2787
2788<h3><a name="reference">How to tune catalog usage:</a></h3>
2789
2790<p>The user can change the default catalog behaviour by redirecting queries
2791to its own set of catalogs, this can be done by setting the
2792<code>XML_CATALOG_FILES</code> environment variable to a list of catalogs, an
2793empty one should deactivate loading the default <code>/etc/xml/catalog</code>
2794default catalog</p>
2795
2796<h3><a name="validate">How to debug catalog processing:</a></h3>
2797
2798<p>Setting up the <code>XML_DEBUG_CATALOG</code> environment variable will
2799make libxml output debugging informations for each catalog operations, for
2800example:</p>
2801<pre>orchis:~/XML -&gt; xmllint --memory --noout test/ent2
2802warning: failed to load external entity "title.xml"
2803orchis:~/XML -&gt; export XML_DEBUG_CATALOG=
2804orchis:~/XML -&gt; xmllint --memory --noout test/ent2
2805Failed to parse catalog /etc/xml/catalog
2806Failed to parse catalog /etc/xml/catalog
2807warning: failed to load external entity "title.xml"
2808Catalogs cleanup
2809orchis:~/XML -&gt; </pre>
2810
2811<p>The test/ent2 references an entity, running the parser from memory makes
2812the base URI unavailable and the the "title.xml" entity cannot be loaded.
2813Setting up the debug environment variable allows to detect that an attempt is
2814made to load the <code>/etc/xml/catalog</code> but since it's not present the
2815resolution fails.</p>
2816
2817<p>But the most advanced way to debug XML catalog processing is to use the
2818<strong>xmlcatalog</strong> command shipped with libxml2, it allows to load
2819catalogs and make resolution queries to see what is going on. This is also
2820used for the regression tests:</p>
2821<pre>orchis:~/XML -&gt; ./xmlcatalog test/catalogs/docbook.xml \
2822 "-//OASIS//DTD DocBook XML V4.1.2//EN"
2823http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd
2824orchis:~/XML -&gt; </pre>
2825
2826<p>For debugging what is going on, adding one -v flags increase the verbosity
2827level to indicate the processing done (adding a second flag also indicate
2828what elements are recognized at parsing):</p>
2829<pre>orchis:~/XML -&gt; ./xmlcatalog -v test/catalogs/docbook.xml \
2830 "-//OASIS//DTD DocBook XML V4.1.2//EN"
2831Parsing catalog test/catalogs/docbook.xml's content
2832Found public match -//OASIS//DTD DocBook XML V4.1.2//EN
2833http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd
2834Catalogs cleanup
2835orchis:~/XML -&gt; </pre>
2836
2837<p>A shell interface is also available to debug and process multiple queries
2838(and for regression tests):</p>
2839<pre>orchis:~/XML -&gt; ./xmlcatalog -shell test/catalogs/docbook.xml \
2840 "-//OASIS//DTD DocBook XML V4.1.2//EN"
2841&gt; help
2842Commands available:
2843public PublicID: make a PUBLIC identifier lookup
2844system SystemID: make a SYSTEM identifier lookup
2845resolve PublicID SystemID: do a full resolver lookup
2846add 'type' 'orig' 'replace' : add an entry
2847del 'values' : remove values
2848dump: print the current catalog state
2849debug: increase the verbosity level
2850quiet: decrease the verbosity level
2851exit: quit the shell
2852&gt; public "-//OASIS//DTD DocBook XML V4.1.2//EN"
2853http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd
2854&gt; quit
2855orchis:~/XML -&gt; </pre>
2856
2857<p>This should be sufficient for most debugging purpose, this was actually
2858used heavily to debug the XML Catalog implementation itself.</p>
2859
2860<h3><a name="Declaring">How to create and maintain</a> catalogs:</h3>
2861
2862<p>Basically XML Catalogs are XML files, you can either use XML tools to
2863manage them or use <strong>xmlcatalog</strong> for this. The basic step is
2864to create a catalog the -create option provide this facility:</p>
2865<pre>orchis:~/XML -&gt; ./xmlcatalog --create tst.xml
2866&lt;?xml version="1.0"?&gt;
2867&lt;!DOCTYPE catalog PUBLIC "-//OASIS//DTD Entity Resolution XML Catalog V1.0//EN"
2868 "http://www.oasis-open.org/committees/entity/release/1.0/catalog.dtd"&gt;
2869&lt;catalog xmlns="urn:oasis:names:tc:entity:xmlns:xml:catalog"/&gt;
2870orchis:~/XML -&gt; </pre>
2871
2872<p>By default xmlcatalog does not overwrite the original catalog and save the
2873result on the standard output, this can be overridden using the -noout
2874option. The <code>-add</code> command allows to add entries in the
2875catalog:</p>
2876<pre>orchis:~/XML -&gt; ./xmlcatalog --noout --create --add "public" \
2877 "-//OASIS//DTD DocBook XML V4.1.2//EN" \
2878 http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd tst.xml
2879orchis:~/XML -&gt; cat tst.xml
2880&lt;?xml version="1.0"?&gt;
2881&lt;!DOCTYPE catalog PUBLIC "-//OASIS//DTD Entity Resolution XML Catalog V1.0//EN" \
2882 "http://www.oasis-open.org/committees/entity/release/1.0/catalog.dtd"&gt;
2883&lt;catalog xmlns="urn:oasis:names:tc:entity:xmlns:xml:catalog"&gt;
2884&lt;public publicId="-//OASIS//DTD DocBook XML V4.1.2//EN"
2885 uri="http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd"/&gt;
2886&lt;/catalog&gt;
2887orchis:~/XML -&gt; </pre>
2888
2889<p>The <code>-add</code> option will always take 3 parameters even if some of
2890the XML Catalog constructs (like nextCatalog) will have only a single
2891argument, just pass a third empty string, it will be ignored.</p>
2892
2893<p>Similarly the <code>-del</code> option remove matching entries from the
2894catalog:</p>
2895<pre>orchis:~/XML -&gt; ./xmlcatalog --del \
2896 "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd" tst.xml
2897&lt;?xml version="1.0"?&gt;
2898&lt;!DOCTYPE catalog PUBLIC "-//OASIS//DTD Entity Resolution XML Catalog V1.0//EN"
2899 "http://www.oasis-open.org/committees/entity/release/1.0/catalog.dtd"&gt;
2900&lt;catalog xmlns="urn:oasis:names:tc:entity:xmlns:xml:catalog"/&gt;
2901orchis:~/XML -&gt; </pre>
2902
2903<p>The catalog is now empty. Note that the matching of <code>-del</code> is
2904exact and would have worked in a similar fashion with the Public ID
2905string.</p>
2906
2907<p>This is rudimentary but should be sufficient to manage a not too complex
2908catalog tree of resources.</p>
2909
2910<h3><a name="implemento">The implementor corner quick review of the
2911API:</a></h3>
2912
2913<p>First, and like for every other module of libxml, there is an
2914automatically generated <a href="html/libxml-catalog.html">API page for
2915catalog support</a>.</p>
2916
2917<p>The header for the catalog interfaces should be included as:</p>
2918<pre>#include &lt;libxml/catalog.h&gt;</pre>
2919
2920<p>The API is voluntarily kept very simple. First it is not obvious that
2921applications really need access to it since it is the default behaviour of
2922libxml (Note: it is possible to completely override libxml default catalog by
2923using <a href="html/libxml-parser.html">xmlSetExternalEntityLoader</a> to
2924plug an application specific resolver).</p>
2925
2926<p>Basically libxml support 2 catalog lists:</p>
2927<ul>
2928 <li>the default one, global shared by all the application</li>
2929 <li>a per-document catalog, this one is built if the document uses the
2930 <code>oasis-xml-catalog</code> PIs to specify its own catalog list, it is
2931 associated to the parser context and destroyed when the parsing context
2932 is destroyed.</li>
2933</ul>
2934
2935<p>the document one will be used first if it exists.</p>
2936
2937<h4>Initialization routines:</h4>
2938
2939<p>xmlInitializeCatalog(), xmlLoadCatalog() and xmlLoadCatalogs() should be
2940used at startup to initialize the catalog, if the catalog should be
2941initialized with specific values xmlLoadCatalog() or xmlLoadCatalogs()
2942should be called before xmlInitializeCatalog() which would otherwise do a
2943default initialization first.</p>
2944
2945<p>The xmlCatalogAddLocal() call is used by the parser to grow the document
2946own catalog list if needed.</p>
2947
2948<h4>Preferences setup:</h4>
2949
2950<p>The XML Catalog spec requires the possibility to select default
2951preferences between public and system delegation,
2952xmlCatalogSetDefaultPrefer() allows this, xmlCatalogSetDefaults() and
2953xmlCatalogGetDefaults() allow to control if XML Catalogs resolution should
2954be forbidden, allowed for global catalog, for document catalog or both, the
2955default is to allow both.</p>
2956
2957<p>And of course xmlCatalogSetDebug() allows to generate debug messages
2958(through the xmlGenericError() mechanism).</p>
2959
2960<h4>Querying routines:</h4>
2961
2962<p>xmlCatalogResolve(), xmlCatalogResolveSystem(), xmlCatalogResolvePublic()
2963and xmlCatalogResolveURI() are relatively explicit if you read the XML
2964Catalog specification they correspond to section 7 algorithms, they should
2965also work if you have loaded an SGML catalog with a simplified semantic.</p>
2966
2967<p>xmlCatalogLocalResolve() and xmlCatalogLocalResolveURI() are the same but
2968operate on the document catalog list</p>
2969
2970<h4>Cleanup and Miscellaneous:</h4>
2971
2972<p>xmlCatalogCleanup() free-up the global catalog, xmlCatalogFreeLocal() is
2973the per-document equivalent.</p>
2974
2975<p>xmlCatalogAdd() and xmlCatalogRemove() are used to dynamically modify the
2976first catalog in the global list, and xmlCatalogDump() allows to dump a
2977catalog state, those routines are primarily designed for xmlcatalog, I'm not
2978sure that exposing more complex interfaces (like navigation ones) would be
2979really useful.</p>
2980
2981<p>The xmlParseCatalogFile() is a function used to load XML Catalog files,
2982it's similar as xmlParseFile() except it bypass all catalog lookups, it's
2983provided because this functionality may be useful for client tools.</p>
2984
2985<h4>threaded environments:</h4>
2986
2987<p>Since the catalog tree is built progressively, some care has been taken to
2988try to avoid troubles in multithreaded environments. The code is now thread
2989safe assuming that the libxml library has been compiled with threads
2990support.</p>
2991
2992<p></p>
2993
2994<h3><a name="Other">Other resources</a></h3>
2995
2996<p>The XML Catalog specification is relatively recent so there isn't much
2997literature to point at:</p>
2998<ul>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]2999 <li>You can find a good rant from Norm Walsh about <a
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3000 href="http://www.arbortext.com/Think_Tank/XML_Resources/Issue_Three/issue_three.html">the
3001 need for catalogs</a>, it provides a lot of context informations even if
Daniel Veillard93d3a472002-04-26 14:04:55 +0000[diff] [blame]3002 I don't agree with everything presented. Norm also wrote a more recent
3003 article <a
3004 href="http://wwws.sun.com/software/xml/developers/resolver/article/">XML
3005 entities and URI resolvers</a> describing them.</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3006 <li>An <a href="http://home.ccil.org/~cowan/XML/XCatalog.html">old XML
3007 catalog proposal</a> from John Cowan</li>
3008 <li>The <a href="http://www.rddl.org/">Resource Directory Description
3009 Language</a> (RDDL) another catalog system but more oriented toward
3010 providing metadata for XML namespaces.</li>
3011 <li>the page from the OASIS Technical <a
3012 href="http://www.oasis-open.org/committees/entity/">Committee on Entity
3013 Resolution</a> who maintains XML Catalog, you will find pointers to the
3014 specification update, some background and pointers to others tools
3015 providing XML Catalog support</li>
Daniel Veillard35e937a2002-01-19 22:21:54 +0000[diff] [blame]3016 <li>Here is a <a href="buildDocBookCatalog">shell script</a> to generate
3017 XML Catalogs for DocBook 4.1.2 . If it can write to the /etc/xml/
3018 directory, it will set-up /etc/xml/catalog and /etc/xml/docbook based on
3019 the resources found on the system. Otherwise it will just create
3020 ~/xmlcatalog and ~/dbkxmlcatalog and doing:
Daniel Veillardc575b992002-02-08 13:28:40 +0000[diff] [blame]3021 <p><code>export XMLCATALOG=$HOME/xmlcatalog</code></p>
Daniel Veillard35e937a2002-01-19 22:21:54 +0000[diff] [blame]3022 <p>should allow to process DocBook documentations without requiring
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]3023 network accesses for the DTD or stylesheets</p>
Daniel Veillard35e937a2002-01-19 22:21:54 +0000[diff] [blame]3024 </li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3025 <li>I have uploaded <a href="ftp://xmlsoft.org/test/dbk412catalog.tar.gz">a
Daniel Veillard35e937a2002-01-19 22:21:54 +0000[diff] [blame]3026 small tarball</a> containing XML Catalogs for DocBook 4.1.2 which seems
3027 to work fine for me too</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3028 <li>The <a href="http://www.xmlsoft.org/xmlcatalog_man.html">xmlcatalog
3029 manual page</a></li>
3030</ul>
3031
3032<p>If you have suggestions for corrections or additions, simply contact
3033me:</p>
3034
3035<h2><a name="library">The parser interfaces</a></h2>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3036
3037<p>This section is directly intended to help programmers getting bootstrapped
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3038using the XML library from the C language. It is not intended to be
3039extensive. I hope the automatically generated documents will provide the
3040completeness required, but as a separate set of documents. The interfaces of
3041the XML library are by principle low level, there is nearly zero abstraction.
3042Those interested in a higher level API should <a href="#DOM">look at
3043DOM</a>.</p>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]3044
Daniel Veillard9cb5ff42001-01-29 08:22:21 +0000[diff] [blame]3045<p>The <a href="html/libxml-parser.html">parser interfaces for XML</a> are
3046separated from the <a href="html/libxml-htmlparser.html">HTML parser
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3047interfaces</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]3048
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3049<h3><a name="Invoking">Invoking the parser : the pull method</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3050
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3051<p>Usually, the first thing to do is to read an XML input. The parser accepts
3052documents either from in-memory strings or from files. The functions are
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3053defined in "parser.h":</p>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]3054<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3055 <dt><code>xmlDocPtr xmlParseMemory(char *buffer, int size);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3056 <dd><p>Parse a null-terminated string containing the document.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3057 </dd>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]3058</dl>
3059<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3060 <dt><code>xmlDocPtr xmlParseFile(const char *filename);</code></dt>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]3061 <dd><p>Parse an XML document contained in a (possibly compressed)
3062 file.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3063 </dd>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]3064</dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3065
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3066<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]3067failure).</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3068
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3069<h3 id="Invoking1">Invoking the parser: the push method</h3>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]3070
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3071<p>In order for the application to keep the control when the document is
3072being fetched (which is common for GUI based programs) libxml provides a push
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3073interface, too, as of version 1.8.3. Here are the interface functions:</p>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]3074<pre>xmlParserCtxtPtr xmlCreatePushParserCtxt(xmlSAXHandlerPtr sax,
3075 void *user_data,
3076 const char *chunk,
3077 int size,
3078 const char *filename);
3079int xmlParseChunk (xmlParserCtxtPtr ctxt,
3080 const char *chunk,
3081 int size,
3082 int terminate);</pre>
3083
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3084<p>and here is a simple example showing how to use the interface:</p>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]3085<pre> FILE *f;
3086
3087 f = fopen(filename, "r");
3088 if (f != NULL) {
3089 int res, size = 1024;
3090 char chars[1024];
3091 xmlParserCtxtPtr ctxt;
3092
3093 res = fread(chars, 1, 4, f);
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3094 if (res &gt; 0) {
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]3095 ctxt = xmlCreatePushParserCtxt(NULL, NULL,
3096 chars, res, filename);
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3097 while ((res = fread(chars, 1, size, f)) &gt; 0) {
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]3098 xmlParseChunk(ctxt, chars, res, 0);
3099 }
3100 xmlParseChunk(ctxt, chars, 0, 1);
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3101 doc = ctxt-&gt;myDoc;
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]3102 xmlFreeParserCtxt(ctxt);
3103 }
3104 }</pre>
3105
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]3106<p>The HTML parser embedded into libxml also has a push interface; the
3107functions are just prefixed by "html" rather than "xml".</p>
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]3108
3109<h3 id="Invoking2">Invoking the parser: the SAX interface</h3>
3110
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]3111<p>The tree-building interface makes the parser memory-hungry, first loading
3112the document in memory and then building the tree itself. Reading a document
3113without building the tree is possible using the SAX interfaces (see SAX.h and
3114<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]3115Henstridge's documentation</a>). Note also that the push interface can be
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3116limited to SAX: just use the two first arguments of
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]3117<code>xmlCreatePushParserCtxt()</code>.</p>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]3118
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]3119<h3><a name="Building">Building a tree from scratch</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3120
3121<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]3122there is a set of functions dedicated to building new elements. (These are
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3123also described in &lt;libxml/tree.h&gt;.) For example, here is a piece of
3124code that produces the XML document used in the previous examples:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3125<pre> #include &lt;libxml/tree.h&gt;
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]3126 xmlDocPtr doc;
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3127 xmlNodePtr tree, subtree;
3128
3129 doc = xmlNewDoc("1.0");
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3130 doc-&gt;children = xmlNewDocNode(doc, NULL, "EXAMPLE", NULL);
3131 xmlSetProp(doc-&gt;children, "prop1", "gnome is great");
3132 xmlSetProp(doc-&gt;children, "prop2", "&amp; linux too");
3133 tree = xmlNewChild(doc-&gt;children, NULL, "head", NULL);
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3134 subtree = xmlNewChild(tree, NULL, "title", "Welcome to Gnome");
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3135 tree = xmlNewChild(doc-&gt;children, NULL, "chapter", NULL);
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3136 subtree = xmlNewChild(tree, NULL, "title", "The Linux adventure");
3137 subtree = xmlNewChild(tree, NULL, "p", "bla bla bla ...");
3138 subtree = xmlNewChild(tree, NULL, "image", NULL);
3139 xmlSetProp(subtree, "href", "linus.gif");</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3140
3141<p>Not really rocket science ...</p>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3142
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]3143<h3><a name="Traversing">Traversing the tree</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3144
Daniel Veillard9cb5ff42001-01-29 08:22:21 +0000[diff] [blame]3145<p>Basically by <a href="html/libxml-tree.html">including "tree.h"</a> your
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3146code has access to the internal structure of all the elements of the tree.
3147The names should be somewhat simple like <strong>parent</strong>,
Daniel Veillard306be992000-07-03 12:38:45 +0000[diff] [blame]3148<strong>children</strong>, <strong>next</strong>, <strong>prev</strong>,
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3149<strong>properties</strong>, etc... For example, still with the previous
Daniel Veillard0142b842000-01-14 14:45:24 +0000[diff] [blame]3150example:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3151<pre><code>doc-&gt;children-&gt;children-&gt;children</code></pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3152
3153<p>points to the title element,</p>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3154<pre>doc-&gt;children-&gt;children-&gt;next-&gt;children-&gt;children</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3155
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]3156<p>points to the text node containing the chapter title "The Linux
3157adventure".</p>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]3158
Daniel Veillardb24054a1999-12-18 15:32:46 +0000[diff] [blame]3159<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]3160present before the document root, so <code>doc-&gt;children</code> may point
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3161to an element which is not the document Root Element; a function
Daniel Veillard5cb5ab81999-12-21 15:35:29 +0000[diff] [blame]3162<code>xmlDocGetRootElement()</code> was added for this purpose.</p>
Daniel Veillardb24054a1999-12-18 15:32:46 +0000[diff] [blame]3163
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]3164<h3><a name="Modifying">Modifying the tree</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3165
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3166<p>Functions are provided for reading and writing the document content. Here
Daniel Veillard9cb5ff42001-01-29 08:22:21 +0000[diff] [blame]3167is an excerpt from the <a href="html/libxml-tree.html">tree API</a>:</p>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3168<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +0000[diff] [blame]3169 <dt><code>xmlAttrPtr xmlSetProp(xmlNodePtr node, const xmlChar *name, const
3170 xmlChar *value);</code></dt>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3171 <dd><p>This sets (or changes) an attribute carried by an ELEMENT node.
3172 The value can be NULL.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3173 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3174</dl>
3175<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +0000[diff] [blame]3176 <dt><code>const xmlChar *xmlGetProp(xmlNodePtr node, const xmlChar
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3177 *name);</code></dt>
Daniel Veillardc92c3042000-09-29 02:42:04 +0000[diff] [blame]3178 <dd><p>This function returns a pointer to new copy of the property
3179 content. Note that the user must deallocate the result.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3180 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3181</dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3182
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3183<p>Two functions are provided for reading and writing the text associated
3184with elements:</p>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3185<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +0000[diff] [blame]3186 <dt><code>xmlNodePtr xmlStringGetNodeList(xmlDocPtr doc, const xmlChar
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3187 *value);</code></dt>
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]3188 <dd><p>This function takes an "external" string and converts it to one
3189 text node or possibly to a list of entity and text nodes. All
3190 non-predefined entity references like &amp;Gnome; will be stored
3191 internally as entity nodes, hence the result of the function may not be
3192 a single node.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3193 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3194</dl>
3195<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +0000[diff] [blame]3196 <dt><code>xmlChar *xmlNodeListGetString(xmlDocPtr doc, xmlNodePtr list, int
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3197 inLine);</code></dt>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]3198 <dd><p>This function is the inverse of
3199 <code>xmlStringGetNodeList()</code>. It generates a new string
3200 containing the content of the text and entity nodes. Note the extra
3201 argument inLine. If this argument is set to 1, the function will expand
3202 entity references. For example, instead of returning the &amp;Gnome;
3203 XML encoding in the string, it will substitute it with its value (say,
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3204 "GNU Network Object Model Environment").</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3205 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3206</dl>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]3207
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]3208<h3><a name="Saving">Saving a tree</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3209
3210<p>Basically 3 options are possible:</p>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3211<dl>
Daniel Veillarddd6b3671999-09-23 22:19:22 +0000[diff] [blame]3212 <dt><code>void xmlDocDumpMemory(xmlDocPtr cur, xmlChar**mem, int
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3213 *size);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3214 <dd><p>Returns a buffer into which the document has been saved.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3215 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3216</dl>
3217<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3218 <dt><code>extern void xmlDocDump(FILE *f, xmlDocPtr doc);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3219 <dd><p>Dumps a document to an open file descriptor.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3220 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3221</dl>
3222<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3223 <dt><code>int xmlSaveFile(const char *filename, xmlDocPtr cur);</code></dt>
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]3224 <dd><p>Saves the document to a file. In this case, the compression
3225 interface is triggered if it has been turned on.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3226 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3227</dl>
Daniel Veillard10c6a8f1998-10-28 01:00:12 +0000[diff] [blame]3228
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]3229<h3><a name="Compressio">Compression</a></h3>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3230
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3231<p>The library transparently handles compression when doing file-based
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]3232accesses. The level of compression on saves can be turned on either globally
3233or individually for one file:</p>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3234<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3235 <dt><code>int xmlGetDocCompressMode (xmlDocPtr doc);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3236 <dd><p>Gets the document compression ratio (0-9).</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3237 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3238</dl>
3239<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3240 <dt><code>void xmlSetDocCompressMode (xmlDocPtr doc, int mode);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3241 <dd><p>Sets the document compression ratio.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3242 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3243</dl>
3244<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3245 <dt><code>int xmlGetCompressMode(void);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3246 <dd><p>Gets the default compression ratio.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3247 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3248</dl>
3249<dl>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3250 <dt><code>void xmlSetCompressMode(int mode);</code></dt>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3251 <dd><p>Sets the default compression ratio.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3252 </dd>
Daniel Veillard25940b71998-10-29 05:51:30 +0000[diff] [blame]3253</dl>
3254
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]3255<h2><a name="Entities">Entities or no entities</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3256
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3257<p>Entities in principle are similar to simple C macros. An entity defines an
3258abbreviation for a given string that you can reuse many times throughout the
3259content of your document. Entities are especially useful when a given string
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]3260may occur frequently within a document, or to confine the change needed to a
3261document to a restricted area in the internal subset of the document (at the
3262beginning). Example:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3263<pre>1 &lt;?xml version="1.0"?&gt;
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]32642 &lt;!DOCTYPE EXAMPLE SYSTEM "example.dtd" [
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]32653 &lt;!ENTITY xml "Extensible Markup Language"&gt;
32664 ]&gt;
32675 &lt;EXAMPLE&gt;
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]32686 &amp;xml;
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]32697 &lt;/EXAMPLE&gt;</pre>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3270
3271<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]3272its name with '&amp;' and following it by ';' without any spaces added. There
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]3273are 5 predefined entities in libxml allowing you to escape characters with
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3274predefined meaning in some parts of the xml document content:
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3275<strong>&amp;lt;</strong> for the character '&lt;', <strong>&amp;gt;</strong>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3276for the character '&gt;', <strong>&amp;apos;</strong> for the character ''',
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3277<strong>&amp;quot;</strong> for the character '"', and
3278<strong>&amp;amp;</strong> for the character '&amp;'.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3279
3280<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]3281substitute an entity's content so that you can see the replacement text in
3282your application. Or you may prefer to keep entity references as such in the
3283content to be able to save the document back without losing this usually
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3284precious information (if the user went through the pain of explicitly
3285defining entities, he may have a a rather negative attitude if you blindly
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]3286substitute them as saving time). The <a
Daniel Veillard9cb5ff42001-01-29 08:22:21 +0000[diff] [blame]3287href="html/libxml-parser.html#XMLSUBSTITUTEENTITIESDEFAULT">xmlSubstituteEntitiesDefault()</a>
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3288function allows you to check and change the behaviour, which is to not
3289substitute entities by default.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3290
3291<p>Here is the DOM tree built by libxml for the previous document in the
3292default case:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3293<pre>/gnome/src/gnome-xml -&gt; ./xmllint --debug test/ent1
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3294DOCUMENT
3295version=1.0
3296 ELEMENT EXAMPLE
3297 TEXT
3298 content=
3299 ENTITY_REF
3300 INTERNAL_GENERAL_ENTITY xml
3301 content=Extensible Markup Language
3302 TEXT
3303 content=</pre>
3304
3305<p>And here is the result when substituting entities:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3306<pre>/gnome/src/gnome-xml -&gt; ./tester --debug --noent test/ent1
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3307DOCUMENT
3308version=1.0
3309 ELEMENT EXAMPLE
3310 TEXT
3311 content= Extensible Markup Language</pre>
3312
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3313<p>So, entities or no entities? Basically, it depends on your use case. I
3314suggest that you keep the non-substituting default behaviour and avoid using
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3315entities in your XML document or data if you are not willing to handle the
3316entity references elements in the DOM tree.</p>
3317
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3318<p>Note that at save time libxml enforces the conversion of the predefined
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3319entities where necessary to prevent well-formedness problems, and will also
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3320transparently replace those with chars (i.e. it will not generate entity
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3321reference elements in the DOM tree or call the reference() SAX callback when
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3322finding them in the input).</p>
3323
Daniel Veillard7b9c4b72000-08-25 16:26:50 +0000[diff] [blame]3324<p><span style="background-color: #FF0000">WARNING</span>: handling entities
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3325on top of the libxml SAX interface is difficult!!! If you plan to use
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]3326non-predefined entities in your documents, then the learning curve to handle
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3327then 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]3328strongly suggest you consider using the DOM interface instead and let libxml
Daniel Veillard8c6d6af2000-08-25 17:14:13 +0000[diff] [blame]3329deal with the complexity rather than trying to do it yourself.</p>
Daniel Veillard7b9c4b72000-08-25 16:26:50 +0000[diff] [blame]3330
Daniel Veillard2f4dfc41999-09-24 14:03:48 +0000[diff] [blame]3331<h2><a name="Namespaces">Namespaces</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3332
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]3333<p>The libxml library implements <a
3334href="http://www.w3.org/TR/REC-xml-names/">XML namespaces</a> support by
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]3335recognizing namespace constructs in the input, and does namespace lookup
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]3336automatically when building the DOM tree. A namespace declaration is
3337associated with an in-memory structure and all elements or attributes within
3338that namespace point to it. Hence testing the namespace is a simple and fast
3339equality operation at the user level.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3340
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]3341<p>I suggest that people using libxml use a namespace, and declare it in the
3342root element of their document as the default namespace. Then they don't need
3343to 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]3344refinement and merging of data from different sources. This doesn't increase
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]3345the size of the XML output significantly, but significantly increases its
3346value in the long-term. Example:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3347<pre>&lt;mydoc xmlns="http://mydoc.example.org/schemas/"&gt;
3348 &lt;elem1&gt;...&lt;/elem1&gt;
3349 &lt;elem2&gt;...&lt;/elem2&gt;
3350&lt;/mydoc&gt;</pre>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3351
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]3352<p>The namespace value has to be an absolute URL, but the URL doesn't have to
3353point to any existing resource on the Web. It will bind all the element and
Daniel Veillardc0801af2002-05-28 16:28:42 +0000[diff] [blame]3354attributes with that URL. I suggest to use an URL within a domain you
3355control, and that the URL should contain some kind of version information if
3356possible. For example, <code>"http://www.gnome.org/gnumeric/1.0/"</code> is a
3357good namespace scheme.</p>
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]3358
3359<p>Then when you load a file, make sure that a namespace carrying the
Daniel Veillard88f00ae2000-03-02 00:15:55 +0000[diff] [blame]3360version-independent prefix is installed on the root element of your document,
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3361and if the version information don't match something you know, warn the user
3362and 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]3363namespace checking on the prefix value. &lt;foo:text&gt; may be exactly the
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3364same as &lt;bar:text&gt; in another document. What really matters is the URI
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3365associated with the element or the attribute, not the prefix string (which is
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3366just a shortcut for the full URI). In libxml, element and attributes have an
Daniel Veillardec303412000-03-24 13:41:54 +0000[diff] [blame]3367<code>ns</code> field pointing to an xmlNs structure detailing the namespace
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3368prefix and its URI.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3369
3370<p>@@Interfaces@@</p>
3371
3372<p>@@Examples@@</p>
3373
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3374<p>Usually people object to using namespaces together with validity checking.
3375I will try to make sure that using namespaces won't break validity checking,
3376so even if you plan to use or currently are using validation I strongly
Daniel Veillardf13e1ed2000-03-06 07:41:49 +0000[diff] [blame]3377suggest adding namespaces to your document. A default namespace scheme
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3378<code>xmlns="http://...."</code> should not break validity even on less
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3379flexible parsers. Using namespaces to mix and differentiate content coming
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3380from multiple DTDs will certainly break current validation schemes. I will
3381try to provide ways to do this, but this may not be portable or
3382standardized.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3383
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3384<h2><a name="Upgrading">Upgrading 1.x code</a></h2>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3385
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3386<p>Incompatible changes:</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3387
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3388<p>Version 2 of libxml is the first version introducing serious backward
3389incompatible changes. The main goals were:</p>
3390<ul>
3391 <li>a general cleanup. A number of mistakes inherited from the very early
3392 versions couldn't be changed due to compatibility constraints. Example
3393 the "childs" element in the nodes.</li>
3394 <li>Uniformization of the various nodes, at least for their header and link
3395 parts (doc, parent, children, prev, next), the goal is a simpler
3396 programming model and simplifying the task of the DOM implementors.</li>
3397 <li>better conformances to the XML specification, for example version 1.x
3398 had an heuristic to try to detect ignorable white spaces. As a result the
3399 SAX event generated were ignorableWhitespace() while the spec requires
3400 character() in that case. This also mean that a number of DOM node
3401 containing blank text may populate the DOM tree which were not present
3402 before.</li>
3403</ul>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3404
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3405<h3>How to fix libxml-1.x code:</h3>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3406
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3407<p>So client code of libxml designed to run with version 1.x may have to be
3408changed to compile against version 2.x of libxml. Here is a list of changes
3409that I have collected, they may not be sufficient, so in case you find other
3410change which are required, <a href="mailto:Daniel.Ïeillardw3.org">drop me a
3411mail</a>:</p>
3412<ol>
3413 <li>The package name have changed from libxml to libxml2, the library name
3414 is now -lxml2 . There is a new xml2-config script which should be used to
3415 select the right parameters libxml2</li>
3416 <li>Node <strong>childs</strong> field has been renamed
3417 <strong>children</strong> so s/childs/children/g should be applied
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]3418 (probability of having "childs" anywhere else is close to 0+</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3419 <li>The document don't have anymore a <strong>root</strong> element it has
3420 been replaced by <strong>children</strong> and usually you will get a
3421 list of element here. For example a Dtd element for the internal subset
3422 and it's declaration may be found in that list, as well as processing
3423 instructions or comments found before or after the document root element.
3424 Use <strong>xmlDocGetRootElement(doc)</strong> to get the root element of
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]3425 a document. Alternatively if you are sure to not reference DTDs nor have
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3426 PIs or comments before or after the root element
3427 s/-&gt;root/-&gt;children/g will probably do it.</li>
3428 <li>The white space issue, this one is more complex, unless special case of
3429 validating parsing, the line breaks and spaces usually used for indenting
3430 and formatting the document content becomes significant. So they are
3431 reported by SAX and if your using the DOM tree, corresponding nodes are
3432 generated. Too approach can be taken:
3433 <ol>
3434 <li>lazy one, use the compatibility call
3435 <strong>xmlKeepBlanksDefault(0)</strong> but be aware that you are
3436 relying on a special (and possibly broken) set of heuristics of
3437 libxml to detect ignorable blanks. Don't complain if it breaks or
3438 make your application not 100% clean w.r.t. to it's input.</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]3439 <li>the Right Way: change you code to accept possibly insignificant
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3440 blanks characters, or have your tree populated with weird blank text
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]3441 nodes. You can spot them using the commodity function
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3442 <strong>xmlIsBlankNode(node)</strong> returning 1 for such blank
3443 nodes.</li>
3444 </ol>
3445 <p>Note also that with the new default the output functions don't add any
3446 extra indentation when saving a tree in order to be able to round trip
3447 (read and save) without inflating the document with extra formatting
3448 chars.</p>
3449 </li>
3450 <li>The include path has changed to $prefix/libxml/ and the includes
3451 themselves uses this new prefix in includes instructions... If you are
3452 using (as expected) the
3453 <pre>xml2-config --cflags</pre>
3454 <p>output to generate you compile commands this will probably work out of
3455 the box</p>
3456 </li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]3457 <li>xmlDetectCharEncoding takes an extra argument indicating the length in
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3458 byte of the head of the document available for character detection.</li>
3459</ol>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3460
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3461<h3>Ensuring both libxml-1.x and libxml-2.x compatibility</h3>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3462
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3463<p>Two new version of libxml (1.8.11) and libxml2 (2.3.4) have been released
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]3464to allow smooth upgrade of existing libxml v1code while retaining
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3465compatibility. They offers the following:</p>
3466<ol>
3467 <li>similar include naming, one should use
3468 <strong>#include&lt;libxml/...&gt;</strong> in both cases.</li>
3469 <li>similar identifiers defined via macros for the child and root fields:
3470 respectively <strong>xmlChildrenNode</strong> and
3471 <strong>xmlRootNode</strong></li>
3472 <li>a new macro <strong>LIBXML_TEST_VERSION</strong> which should be
3473 inserted once in the client code</li>
3474</ol>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3475
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3476<p>So the roadmap to upgrade your existing libxml applications is the
3477following:</p>
3478<ol>
3479 <li>install the libxml-1.8.8 (and libxml-devel-1.8.8) packages</li>
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]3480 <li>find all occurrences where the xmlDoc <strong>root</strong> field is
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3481 used and change it to <strong>xmlRootNode</strong></li>
Daniel Veillardc0801af2002-05-28 16:28:42 +0000[diff] [blame]3482 <li>similarly find all occurrences where the xmlNode
3483 <strong>childs</strong> field is used and change it to
3484 <strong>xmlChildrenNode</strong></li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3485 <li>add a <strong>LIBXML_TEST_VERSION</strong> macro somewhere in your
3486 <strong>main()</strong> or in the library init entry point</li>
3487 <li>Recompile, check compatibility, it should still work</li>
Daniel Veillardc0801af2002-05-28 16:28:42 +0000[diff] [blame]3488 <li>Change your configure script to look first for xml2-config and fall
3489 back using xml-config . Use the --cflags and --libs output of the command
3490 as the Include and Linking parameters needed to use libxml.</li>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3491 <li>install libxml2-2.3.x and libxml2-devel-2.3.x (libxml-1.8.y and
3492 libxml-devel-1.8.y can be kept simultaneously)</li>
3493 <li>remove your config.cache, relaunch your configuration mechanism, and
3494 recompile, if steps 2 and 3 were done right it should compile as-is</li>
3495 <li>Test that your application is still running correctly, if not this may
3496 be due to extra empty nodes due to formating spaces being kept in libxml2
3497 contrary to libxml1, in that case insert xmlKeepBlanksDefault(1) in your
3498 code before calling the parser (next to
3499 <strong>LIBXML_TEST_VERSION</strong> is a fine place).</li>
3500</ol>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3501
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3502<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]3503
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3504<p>Let me put some emphasis on the fact that there is far more changes from
3505libxml 1.x to 2.x than the ones you may have to patch for. The overall code
3506has been considerably cleaned up and the conformance to the XML specification
3507has been drastically improved too. Don't take those changes as an excuse to
3508not upgrade, it may cost a lot on the long term ...</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3509
Daniel Veillard52dcab32001-10-30 12:51:17 +0000[diff] [blame]3510<h2><a name="Thread">Thread safety</a></h2>
3511
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]3512<p>Starting with 2.4.7, libxml makes provisions to ensure that concurrent
Daniel Veillard52dcab32001-10-30 12:51:17 +0000[diff] [blame]3513threads can safely work in parallel parsing different documents. There is
3514however a couple of things to do to ensure it:</p>
3515<ul>
3516 <li>configure the library accordingly using the --with-threads options</li>
3517 <li>call xmlInitParser() in the "main" thread before using any of the
3518 libxml API (except possibly selecting a different memory allocator)</li>
3519</ul>
3520
3521<p>Note that the thread safety cannot be ensured for multiple threads sharing
3522the same document, the locking must be done at the application level, libxml
3523exports a basic mutex and reentrant mutexes API in &lt;libxml/threads.h&gt;.
3524The parts of the library checked for thread safety are:</p>
3525<ul>
3526 <li>concurrent loading</li>
3527 <li>file access resolution</li>
3528 <li>catalog access</li>
3529 <li>catalog building</li>
3530 <li>entities lookup/accesses</li>
3531 <li>validation</li>
3532 <li>global variables per-thread override</li>
3533 <li>memory handling</li>
3534</ul>
3535
3536<p>XPath is supposed to be thread safe now, but this wasn't tested
3537seriously.</p>
3538
Daniel Veillard35008381999-10-25 13:15:52 +0000[diff] [blame]3539<h2><a name="DOM"></a><a name="Principles">DOM Principles</a></h2>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3540
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3541<p><a href="http://www.w3.org/DOM/">DOM</a> stands for the <em>Document
3542Object Model</em>; this is an API for accessing XML or HTML structured
3543documents. Native support for DOM in Gnome is on the way (module gnome-dom),
3544and will be based on gnome-xml. This will be a far cleaner interface to
3545manipulate XML files within Gnome since it won't expose the internal
3546structure.</p>
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3547
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3548<p>The current DOM implementation on top of libxml is the <a
Daniel Veillarda47fb3d2001-03-25 17:23:49 +0000[diff] [blame]3549href="http://cvs.gnome.org/lxr/source/gdome2/">gdome2 Gnome module</a>, this
3550is a full DOM interface, thanks to Paolo Casarini, check the <a
3551href="http://www.cs.unibo.it/~casarini/gdome2/">Gdome2 homepage</a> for more
3552informations.</p>
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3553
Daniel Veillard35008381999-10-25 13:15:52 +0000[diff] [blame]3554<h2><a name="Example"></a><a name="real">A real example</a></h2>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3555
3556<p>Here is a real size example, where the actual content of the application
3557data 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]3558a proposal to keep a database of jobs related to Gnome, with an XML based
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3559storage structure. Here is an <a href="gjobs.xml">XML encoded jobs
3560base</a>:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3561<pre>&lt;?xml version="1.0"?&gt;
3562&lt;gjob:Helping xmlns:gjob="http://www.gnome.org/some-location"&gt;
3563 &lt;gjob:Jobs&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3564
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3565 &lt;gjob:Job&gt;
3566 &lt;gjob:Project ID="3"/&gt;
3567 &lt;gjob:Application&gt;GBackup&lt;/gjob:Application&gt;
3568 &lt;gjob:Category&gt;Development&lt;/gjob:Category&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3569
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3570 &lt;gjob:Update&gt;
3571 &lt;gjob:Status&gt;Open&lt;/gjob:Status&gt;
3572 &lt;gjob:Modified&gt;Mon, 07 Jun 1999 20:27:45 -0400 MET DST&lt;/gjob:Modified&gt;
3573 &lt;gjob:Salary&gt;USD 0.00&lt;/gjob:Salary&gt;
3574 &lt;/gjob:Update&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3575
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3576 &lt;gjob:Developers&gt;
3577 &lt;gjob:Developer&gt;
3578 &lt;/gjob:Developer&gt;
3579 &lt;/gjob:Developers&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3580
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3581 &lt;gjob:Contact&gt;
3582 &lt;gjob:Person&gt;Nathan Clemons&lt;/gjob:Person&gt;
3583 &lt;gjob:Email&gt;nathan@windsofstorm.net&lt;/gjob:Email&gt;
3584 &lt;gjob:Company&gt;
3585 &lt;/gjob:Company&gt;
3586 &lt;gjob:Organisation&gt;
3587 &lt;/gjob:Organisation&gt;
3588 &lt;gjob:Webpage&gt;
3589 &lt;/gjob:Webpage&gt;
3590 &lt;gjob:Snailmail&gt;
3591 &lt;/gjob:Snailmail&gt;
3592 &lt;gjob:Phone&gt;
3593 &lt;/gjob:Phone&gt;
3594 &lt;/gjob:Contact&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3595
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3596 &lt;gjob:Requirements&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3597 The program should be released as free software, under the GPL.
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3598 &lt;/gjob:Requirements&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3599
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3600 &lt;gjob:Skills&gt;
3601 &lt;/gjob:Skills&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3602
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3603 &lt;gjob:Details&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3604 A GNOME based system that will allow a superuser to configure
3605 compressed and uncompressed files and/or file systems to be backed
3606 up with a supported media in the system. This should be able to
3607 perform via find commands generating a list of files that are passed
3608 to tar, dd, cpio, cp, gzip, etc., to be directed to the tape machine
3609 or via operations performed on the filesystem itself. Email
3610 notification and GUI status display very important.
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3611 &lt;/gjob:Details&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3612
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3613 &lt;/gjob:Job&gt;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3614
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3615 &lt;/gjob:Jobs&gt;
3616&lt;/gjob:Helping&gt;</pre>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3617
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3618<p>While loading the XML file into an internal DOM tree is a matter of
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]3619calling only a couple of functions, browsing the tree to gather the data and
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3620generate the internal structures is harder, and more error prone.</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3621
3622<p>The suggested principle is to be tolerant with respect to the input
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3623structure. For example, the ordering of the attributes is not significant,
3624the 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]3625depend on the order of the children of a given node, unless it really makes
3626things harder. Here is some code to parse the information for a person:</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3627<pre>/*
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3628 * A person record
3629 */
3630typedef struct person {
3631 char *name;
3632 char *email;
3633 char *company;
3634 char *organisation;
3635 char *smail;
3636 char *webPage;
3637 char *phone;
3638} person, *personPtr;
3639
3640/*
3641 * And the code needed to parse it
3642 */
3643personPtr parsePerson(xmlDocPtr doc, xmlNsPtr ns, xmlNodePtr cur) {
3644 personPtr ret = NULL;
3645
3646DEBUG("parsePerson\n");
3647 /*
3648 * allocate the struct
3649 */
3650 ret = (personPtr) malloc(sizeof(person));
3651 if (ret == NULL) {
3652 fprintf(stderr,"out of memory\n");
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3653 return(NULL);
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3654 }
3655 memset(ret, 0, sizeof(person));
3656
3657 /* We don't care what the top level element name is */
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3658 cur = cur-&gt;xmlChildrenNode;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3659 while (cur != NULL) {
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3660 if ((!strcmp(cur-&gt;name, "Person")) &amp;&amp; (cur-&gt;ns == ns))
3661 ret-&gt;name = xmlNodeListGetString(doc, cur-&gt;xmlChildrenNode, 1);
3662 if ((!strcmp(cur-&gt;name, "Email")) &amp;&amp; (cur-&gt;ns == ns))
3663 ret-&gt;email = xmlNodeListGetString(doc, cur-&gt;xmlChildrenNode, 1);
3664 cur = cur-&gt;next;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3665 }
3666
3667 return(ret);
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3668}</pre>
3669
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3670<p>Here are a couple of things to notice:</p>
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3671<ul>
Daniel Veillard91e9d582001-02-26 07:31:12 +0000[diff] [blame]3672 <li>Usually a recursive parsing style is the more convenient one: XML data
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]3673 is by nature subject to repetitive constructs and usually exhibits highly
3674 structured patterns.</li>
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3675 <li>The two arguments of type <em>xmlDocPtr</em> and <em>xmlNsPtr</em>,
3676 i.e. the pointer to the global XML document and the namespace reserved to
3677 the application. Document wide information are needed for example to
3678 decode entities and it's a good coding practice to define a namespace for
3679 your application set of data and test that the element and attributes
3680 you're analyzing actually pertains to your application space. This is
3681 done by a simple equality test (cur-&gt;ns == ns).</li>
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]3682 <li>To retrieve text and attributes value, you can use the function
3683 <em>xmlNodeListGetString</em> to gather all the text and entity reference
3684 nodes generated by the DOM output and produce an single text string.</li>
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3685</ul>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3686
3687<p>Here is another piece of code used to parse another level of the
3688structure:</p>
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3689<pre>#include &lt;libxml/tree.h&gt;
Daniel Veillard361d8452000-04-03 19:48:13 +0000[diff] [blame]3690/*
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3691 * a Description for a Job
3692 */
3693typedef struct job {
3694 char *projectID;
3695 char *application;
3696 char *category;
3697 personPtr contact;
3698 int nbDevelopers;
3699 personPtr developers[100]; /* using dynamic alloc is left as an exercise */
3700} job, *jobPtr;
3701
3702/*
3703 * And the code needed to parse it
3704 */
3705jobPtr parseJob(xmlDocPtr doc, xmlNsPtr ns, xmlNodePtr cur) {
3706 jobPtr ret = NULL;
3707
3708DEBUG("parseJob\n");
3709 /*
3710 * allocate the struct
3711 */
3712 ret = (jobPtr) malloc(sizeof(job));
3713 if (ret == NULL) {
3714 fprintf(stderr,"out of memory\n");
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3715 return(NULL);
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3716 }
3717 memset(ret, 0, sizeof(job));
3718
3719 /* We don't care what the top level element name is */
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3720 cur = cur-&gt;xmlChildrenNode;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3721 while (cur != NULL) {
3722
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3723 if ((!strcmp(cur-&gt;name, "Project")) &amp;&amp; (cur-&gt;ns == ns)) {
3724 ret-&gt;projectID = xmlGetProp(cur, "ID");
3725 if (ret-&gt;projectID == NULL) {
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3726 fprintf(stderr, "Project has no ID\n");
3727 }
3728 }
Daniel Veillard60979bd2000-07-10 12:17:33 +0000[diff] [blame]3729 if ((!strcmp(cur-&gt;name, "Application")) &amp;&amp; (cur-&gt;ns == ns))
3730 ret-&gt;application = xmlNodeListGetString(doc, cur-&gt;xmlChildrenNode, 1);
3731 if ((!strcmp(cur-&gt;name, "Category")) &amp;&amp; (cur-&gt;ns == ns))
3732 ret-&gt;category = xmlNodeListGetString(doc, cur-&gt;xmlChildrenNode, 1);
3733 if ((!strcmp(cur-&gt;name, "Contact")) &amp;&amp; (cur-&gt;ns == ns))
3734 ret-&gt;contact = parsePerson(doc, ns, cur);
3735 cur = cur-&gt;next;
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3736 }
3737
3738 return(ret);
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3739}</pre>
Daniel Veillard14fff061999-06-22 21:49:07 +0000[diff] [blame]3740
Daniel Veillardec70e912001-02-26 20:10:45 +0000[diff] [blame]3741<p>Once you are used to it, writing this kind of code is quite simple, but
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]3742boring. Ultimately, it could be possible to write stubbers taking either C
Daniel Veillard3d6ae1c2001-08-15 13:12:39 +0000[diff] [blame]3743data structure definitions, a set of XML examples or an XML DTD and produce
3744the code needed to import and export the content between C data and XML
3745storage. This is left as an exercise to the reader :-)</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3746
Daniel Veillard6f0adb52000-07-03 11:41:26 +0000[diff] [blame]3747<p>Feel free to use <a href="example/gjobread.c">the code for the full C
3748parsing example</a> as a template, it is also available with Makefile in the
3749Gnome CVS base under gnome-xml/example</p>
Daniel Veillardb05deb71999-08-10 19:04:08 +0000[diff] [blame]3750
Daniel Veillardc310d562000-06-23 18:32:15 +0000[diff] [blame]3751<h2><a name="Contributi">Contributions</a></h2>
3752<ul>
Daniel Veillardb8cfbd12001-10-25 10:53:28 +0000[diff] [blame]3753 <li>Bjorn Reese, William Brack and Thomas Broyer have provided a number of
3754 patches, Gary Pennington worked on the validation API, threading support
3755 and Solaris port.</li>
3756 <li>John Fleck helps maintaining the documentation and man pages.</li>
Daniel Veillardb2fb8ed2002-04-01 09:33:12 +0000[diff] [blame]3757 <li><a href="mailto:igor@stud.fh-frankfurt.de">Igor Zlatkovic</a> is now
3758 the maintainer of the Windows port, <a
Daniel Veillard95189532001-07-26 18:30:26 +0000[diff] [blame]3759 href="http://www.fh-frankfurt.de/~igor/projects/libxml/index.html">he
3760 provides binaries</a></li>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]3761 <li><a href="mailto:Gary.Pennington@sun.com">Gary Pennington</a> provides
3762 <a href="http://garypennington.net/libxml2/">Solaris binaries</a></li>
Daniel Veillarde356c282001-03-10 12:32:04 +0000[diff] [blame]3763 <li><a
3764 href="http://mail.gnome.org/archives/xml/2001-March/msg00014.html">Matt
Daniel Veillard63d83142002-05-20 06:51:05 +0000[diff] [blame]3765 Sergeant</a> developed <a
3766 href="http://axkit.org/download/">XML::LibXSLT</a>, a Perl wrapper for
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]3767 libxml2/libxslt as part of the <a href="http://axkit.com/">AxKit XML
3768 application server</a></li>
3769 <li><a href="mailto:fnatter@gmx.net">Felix Natter</a> and <a
3770 href="mailto:geertk@ai.rug.nl">Geert Kloosterman</a> provide <a
Daniel Veillardca989762001-06-23 17:39:29 +0000[diff] [blame]3771 href="libxml-doc.el">an emacs module</a> to lookup libxml(2) functions
Daniel Veillard3f6f7f62000-06-30 17:58:25 +0000[diff] [blame]3772 documentation</li>
Daniel Veillardaf43f632002-03-08 15:05:20 +0000[diff] [blame]3773 <li><a href="mailto:sherwin@nlm.nih.gov">Ziying Sherwin</a> provided <a
3774 href="http://xmlsoft.org/messages/0488.html">man pages</a></li>
Daniel Veillard5168dbf2001-07-07 00:18:23 +0000[diff] [blame]3775 <li>there is a module for <a
3776 href="http://acs-misc.sourceforge.net/nsxml.html">libxml/libxslt support
3777 in OpenNSD/AOLServer</a></li>
Daniel Veillard2d347fa2002-03-17 10:34:11 +0000[diff] [blame]3778 <li><a href="mailto:dkuhlman@cutter.rexx.com">Dave Kuhlman</a> provided the
3779 first version of libxml/libxslt <a
3780 href="http://www.rexx.com/~dkuhlman">wrappers for Python</a></li>
Daniel Veillard1aadc442001-11-28 13:10:32 +0000[diff] [blame]3781 <li>Petr Kozelka provides <a
3782 href="http://sourceforge.net/projects/libxml2-pas">Pascal units to glue
3783 libxml2</a> with Kylix and Delphi and other Pascal compilers</li>
Daniel Veillard2d347fa2002-03-17 10:34:11 +0000[diff] [blame]3784 <li><a href="mailto:aleksey@aleksey.com">Aleksey Sanin</a> implemented the
3785 <a href="http://www.w3.org/Signature/">XML Canonicalization and XML
3786 Digital Signature</a> <a
3787 href="http://www.aleksey.com/xmlsec/">implementations for libxml2</a></li>
Daniel Veillardc310d562000-06-23 18:32:15 +0000[diff] [blame]3788</ul>
3789
Daniel Veillardc8eab3a1999-09-04 18:27:23 +0000[diff] [blame]3790<p></p>
Daniel Veillardccb09631998-10-27 06:21:04 +0000[diff] [blame]3791</body>
3792</html>