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1<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" 2 "http://www.w3.org/TR/html4/loose.dtd"> 3<html> 4<head> 5 <title>The XML C parser and toolkit of Gnome</title> 6 <meta name="GENERATOR" content="amaya 5.1"> 7 <meta http-equiv="Content-Type" content="text/html"> 8</head> 9 10<body bgcolor="#ffffff"> 11<h1 align="center">The XML C parser and toolkit of Gnome</h1> 12 13<h1>Note: this is the flat content of the <a href="index.html">web 14site</a></h1> 15 16<h1 style="text-align: center">libxml, a.k.a. gnome-xml</h1> 17 18<p></p> 19 20<p 21style="text-align: right; font-style: italic; font-size: 10pt">"Programming 22with libxml2 is like the thrilling embrace of an exotic stranger." <a 23href="http://diveintomark.org/archives/2004/02/18/libxml2">Mark 24Pilgrim</a></p> 25 26<p>Libxml2 is the XML C parser and toolkit developed for the Gnome project 27(but usable outside of the Gnome platform), it is free software available 28under the <a href="http://www.opensource.org/licenses/mit-license.html">MIT 29License</a>. XML itself is a metalanguage to design markup languages, i.e. 30text language where semantic and structure are added to the content using 31extra "markup" information enclosed between angle brackets. HTML is the most 32well-known markup language. Though the library is written in C <a 33href="python.html">a variety of language bindings</a> make it available in 34other environments.</p> 35 36<p>Libxml2 is known to be very portable, the library should build and work 37without serious troubles on a variety of systems (Linux, Unix, Windows, 38CygWin, MacOS, MacOS X, RISC Os, OS/2, VMS, QNX, MVS, ...)</p> 39 40<p>Libxml2 implements a number of existing standards related to markup 41languages:</p> 42<ul> 43 <li>the XML standard: <a 44 href="http://www.w3.org/TR/REC-xml">http://www.w3.org/TR/REC-xml</a></li> 45 <li>Namespaces in XML: <a 46 href="http://www.w3.org/TR/REC-xml-names/">http://www.w3.org/TR/REC-xml-names/</a></li> 47 <li>XML Base: <a 48 href="http://www.w3.org/TR/xmlbase/">http://www.w3.org/TR/xmlbase/</a></li> 49 <li><a href="http://www.cis.ohio-state.edu/rfc/rfc2396.txt">RFC 2396</a> : 50 Uniform Resource Identifiers <a 51 href="http://www.ietf.org/rfc/rfc2396.txt">http://www.ietf.org/rfc/rfc2396.txt</a></li> 52 <li>XML Path Language (XPath) 1.0: <a 53 href="http://www.w3.org/TR/xpath">http://www.w3.org/TR/xpath</a></li> 54 <li>HTML4 parser: <a 55 href="http://www.w3.org/TR/html401/">http://www.w3.org/TR/html401/</a></li> 56 <li>XML Pointer Language (XPointer) Version 1.0: <a 57 href="http://www.w3.org/TR/xptr">http://www.w3.org/TR/xptr</a></li> 58 <li>XML Inclusions (XInclude) Version 1.0: <a 59 href="http://www.w3.org/TR/xinclude/">http://www.w3.org/TR/xinclude/</a></li> 60 <li>ISO-8859-x encodings, as well as <a 61 href="http://www.cis.ohio-state.edu/rfc/rfc2044.txt">rfc2044</a> [UTF-8] 62 and <a href="http://www.cis.ohio-state.edu/rfc/rfc2781.txt">rfc2781</a> 63 [UTF-16] Unicode encodings, and more if using iconv support</li> 64 <li>part of SGML Open Technical Resolution TR9401:1997</li> 65 <li>XML Catalogs Working Draft 06 August 2001: <a 66 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> 67 <li>Canonical XML Version 1.0: <a 68 href="http://www.w3.org/TR/xml-c14n">http://www.w3.org/TR/xml-c14n</a> 69 and the Exclusive XML Canonicalization CR draft <a 70 href="http://www.w3.org/TR/xml-exc-c14n">http://www.w3.org/TR/xml-exc-c14n</a></li> 71 <li>Relax NG, ISO/IEC 19757-2:2003, <a 72 href="http://www.oasis-open.org/committees/relax-ng/spec-20011203.html">http://www.oasis-open.org/committees/relax-ng/spec-20011203.html</a></li> 73 <li>W3C XML Schemas Part 2: Datatypes <a 74 href="http://www.w3.org/TR/2001/REC-xmlschema-2-20010502/">REC 02 May 75 2001</a></li> 76 <li>W3C <a href="http://www.w3.org/TR/xml-id/">xml:id</a> Working Draft 7 77 April 2004</li> 78</ul> 79 80<p>In most cases libxml2 tries to implement the specifications in a 81relatively strictly compliant way. As of release 2.4.16, libxml2 passed all 821800+ tests from the <a 83href="http://www.oasis-open.org/committees/xml-conformance/">OASIS XML Tests 84Suite</a>.</p> 85 86<p>To some extent libxml2 provides support for the following additional 87specifications but doesn't claim to implement them completely:</p> 88<ul> 89 <li>Document Object Model (DOM) <a 90 href="http://www.w3.org/TR/DOM-Level-2-Core/">http://www.w3.org/TR/DOM-Level-2-Core/</a> 91 the document model, but it doesn't implement the API itself, gdome2 does 92 this on top of libxml2</li> 93 <li><a href="http://www.cis.ohio-state.edu/rfc/rfc959.txt">RFC 959</a> : 94 libxml2 implements a basic FTP client code</li> 95 <li><a href="http://www.cis.ohio-state.edu/rfc/rfc1945.txt">RFC 1945</a> : 96 HTTP/1.0, again a basic HTTP client code</li> 97 <li>SAX: a SAX2 like interface and a minimal SAX1 implementation compatible 98 with early expat versions</li> 99</ul> 100 101<p>A partial implementation of <a 102href="http://www.w3.org/TR/2001/REC-xmlschema-1-20010502/">XML Schemas Part 1031: Structure</a> is being worked on but it would be far too early to make any 104conformance statement about it at the moment.</p> 105 106<p>Separate documents:</p> 107<ul> 108 <li><a href="http://xmlsoft.org/XSLT/">the libxslt page</a> providing an 109 implementation of XSLT 1.0 and common extensions like EXSLT for 110 libxml2</li> 111 <li><a href="http://www.cs.unibo.it/~casarini/gdome2/">the gdome2 page</a> 112 : a standard DOM2 implementation for libxml2</li> 113 <li><a href="http://www.aleksey.com/xmlsec/">the XMLSec page</a>: an 114 implementation of <a href="http://www.w3.org/TR/xmldsig-core/">W3C XML 115 Digital Signature</a> for libxml2</li> 116 <li>also check the related links section below for more related and active 117 projects.</li> 118</ul> 119<!----------------<p>Results of the <a 120href="http://xmlbench.sourceforge.net/results/benchmark/index.html">xmlbench 121benchmark</a> on sourceforge February 2004 (smaller is better):</p> 122 123<p align="center"><img src="benchmark.png" 124alt="benchmark results for Expat Xerces libxml2 Oracle and Sun toolkits"></p> 125--------------> 126 127 128<p>Logo designed by <a href="mailto:liyanage@access.ch">Marc Liyanage</a>.</p> 129 130<h2><a name="Introducti">Introduction</a></h2> 131 132<p>This document describes libxml, the <a 133href="http://www.w3.org/XML/">XML</a> C parser and toolkit developed for the 134<a href="http://www.gnome.org/">Gnome</a> project. <a 135href="http://www.w3.org/XML/">XML is a standard</a> for building tag-based 136structured documents/data.</p> 137 138<p>Here are some key points about libxml:</p> 139<ul> 140 <li>Libxml2 exports Push (progressive) and Pull (blocking) type parser 141 interfaces for both XML and HTML.</li> 142 <li>Libxml2 can do DTD validation at parse time, using a parsed document 143 instance, or with an arbitrary DTD.</li> 144 <li>Libxml2 includes complete <a 145 href="http://www.w3.org/TR/xpath">XPath</a>, <a 146 href="http://www.w3.org/TR/xptr">XPointer</a> and <a 147 href="http://www.w3.org/TR/xinclude">XInclude</a> implementations.</li> 148 <li>It is written in plain C, making as few assumptions as possible, and 149 sticking closely to ANSI C/POSIX for easy embedding. Works on 150 Linux/Unix/Windows, ported to a number of other platforms.</li> 151 <li>Basic support for HTTP and FTP client allowing applications to fetch 152 remote resources.</li> 153 <li>The design is modular, most of the extensions can be compiled out.</li> 154 <li>The internal document representation is as close as possible to the <a 155 href="http://www.w3.org/DOM/">DOM</a> interfaces.</li> 156 <li>Libxml2 also has a <a 157 href="http://www.megginson.com/SAX/index.html">SAX like interface</a>; 158 the interface is designed to be compatible with <a 159 href="http://www.jclark.com/xml/expat.html">Expat</a>.</li> 160 <li>This library is released under the <a 161 href="http://www.opensource.org/licenses/mit-license.html">MIT 162 License</a>. See the Copyright file in the distribution for the precise 163 wording.</li> 164</ul> 165 166<p>Warning: unless you are forced to because your application links with a 167Gnome-1.X library requiring it, <strong><span 168style="background-color: #FF0000">Do Not Use libxml1</span></strong>, use 169libxml2</p> 170 171<h2><a name="FAQ">FAQ</a></h2> 172 173<p>Table of Contents:</p> 174<ul> 175 <li><a href="FAQ.html#License">License(s)</a></li> 176 <li><a href="FAQ.html#Installati">Installation</a></li> 177 <li><a href="FAQ.html#Compilatio">Compilation</a></li> 178 <li><a href="FAQ.html#Developer">Developer corner</a></li> 179</ul> 180 181<h3><a name="License">License</a>(s)</h3> 182<ol> 183 <li><em>Licensing Terms for libxml</em> 184 <p>libxml2 is released under the <a 185 href="http://www.opensource.org/licenses/mit-license.html">MIT 186 License</a>; see the file Copyright in the distribution for the precise 187 wording</p> 188 </li> 189 <li><em>Can I embed libxml2 in a proprietary application ?</em> 190 <p>Yes. The MIT License allows you to keep proprietary the changes you 191 made to libxml, but it would be graceful to send-back bug fixes and 192 improvements as patches for possible incorporation in the main 193 development tree.</p> 194 </li> 195</ol> 196 197<h3><a name="Installati">Installation</a></h3> 198<ol> 199 <li><strong><span style="background-color: #FF0000">Do Not Use 200 libxml1</span></strong>, use libxml2</li> 201 <li><em>Where can I get libxml</em> ? 202 <p>The original distribution comes from <a 203 href="ftp://rpmfind.net/pub/libxml/">rpmfind.net</a> or <a 204 href="ftp://ftp.gnome.org/pub/GNOME/sources/libxml2/2.6/">gnome.org</a></p> 205 <p>Most Linux and BSD distributions include libxml, this is probably the 206 safer way for end-users to use libxml.</p> 207 <p>David Doolin provides precompiled Windows versions at <a 208 href="http://www.ce.berkeley.edu/~doolin/code/libxmlwin32/ ">http://www.ce.berkeley.edu/~doolin/code/libxmlwin32/</a></p> 209 </li> 210 <li><em>I see libxml and libxml2 releases, which one should I install ?</em> 211 <ul> 212 <li>If you are not constrained by backward compatibility issues with 213 existing applications, install libxml2 only</li> 214 <li>If you are not doing development, you can safely install both. 215 Usually the packages <a 216 href="http://rpmfind.net/linux/RPM/libxml.html">libxml</a> and <a 217 href="http://rpmfind.net/linux/RPM/libxml2.html">libxml2</a> are 218 compatible (this is not the case for development packages).</li> 219 <li>If you are a developer and your system provides separate packaging 220 for shared libraries and the development components, it is possible 221 to install libxml and libxml2, and also <a 222 href="http://rpmfind.net/linux/RPM/libxml-devel.html">libxml-devel</a> 223 and <a 224 href="http://rpmfind.net/linux/RPM/libxml2-devel.html">libxml2-devel</a> 225 too for libxml2 >= 2.3.0</li> 226 <li>If you are developing a new application, please develop against 227 libxml2(-devel)</li> 228 </ul> 229 </li> 230 <li><em>I can't install the libxml package, it conflicts with libxml0</em> 231 <p>You probably have an old libxml0 package used to provide the shared 232 library for libxml.so.0, you can probably safely remove it. The libxml 233 packages provided on <a 234 href="ftp://rpmfind.net/pub/libxml/">rpmfind.net</a> provide 235 libxml.so.0</p> 236 </li> 237 <li><em>I can't install the libxml(2) RPM package due to failed 238 dependencies</em> 239 <p>The most generic solution is to re-fetch the latest src.rpm , and 240 rebuild it locally with</p> 241 <p><code>rpm --rebuild libxml(2)-xxx.src.rpm</code>.</p> 242 <p>If everything goes well it will generate two binary rpm packages (one 243 providing the shared libs and xmllint, and the other one, the -devel 244 package, providing includes, static libraries and scripts needed to build 245 applications with libxml(2)) that you can install locally.</p> 246 </li> 247</ol> 248 249<h3><a name="Compilatio">Compilation</a></h3> 250<ol> 251 <li><em>What is the process to compile libxml2 ?</em> 252 <p>As most UNIX libraries libxml2 follows the "standard":</p> 253 <p><code>gunzip -c xxx.tar.gz | tar xvf -</code></p> 254 <p><code>cd libxml-xxxx</code></p> 255 <p><code>/configure --help</code></p> 256 <p>to see the options, then the compilation/installation proper</p> 257 <p><code>/configure [possible options]</code></p> 258 <p><code>make</code></p> 259 <p><code>make install</code></p> 260 <p>At that point you may have to rerun ldconfig or a similar utility to 261 update your list of installed shared libs.</p> 262 </li> 263 <li><em>What other libraries are needed to compile/install libxml2 ?</em> 264 <p>Libxml2 does not require any other library, the normal C ANSI API 265 should be sufficient (please report any violation to this rule you may 266 find).</p> 267 <p>However if found at configuration time libxml2 will detect and use the 268 following libs:</p> 269 <ul> 270 <li><a href="http://www.info-zip.org/pub/infozip/zlib/">libz</a> : a 271 highly portable and available widely compression library.</li> 272 <li>iconv: a powerful character encoding conversion library. It is 273 included by default in recent glibc libraries, so it doesn't need to 274 be installed specifically on Linux. It now seems a <a 275 href="http://www.opennc.org/onlinepubs/7908799/xsh/iconv.html">part 276 of the official UNIX</a> specification. Here is one <a 277 href="http://www.gnu.org/software/libiconv/">implementation of the 278 library</a> which source can be found <a 279 href="ftp://ftp.ilog.fr/pub/Users/haible/gnu/">here</a>.</li> 280 </ul> 281 </li> 282 <li><em>Make check fails on some platforms</em> 283 <p>Sometimes the regression tests' results don't completely match the 284 value produced by the parser, and the makefile uses diff to print the 285 delta. On some platforms the diff return breaks the compilation process; 286 if the diff is small this is probably not a serious problem.</p> 287 <p>Sometimes (especially on Solaris) make checks fail due to limitations 288 in make. Try using GNU-make instead.</p> 289 </li> 290 <li><em>I use the CVS version and there is no configure script</em> 291 <p>The configure script (and other Makefiles) are generated. Use the 292 autogen.sh script to regenerate the configure script and Makefiles, 293 like:</p> 294 <p><code>/autogen.sh --prefix=/usr --disable-shared</code></p> 295 </li> 296 <li><em>I have troubles when running make tests with gcc-3.0</em> 297 <p>It seems the initial release of gcc-3.0 has a problem with the 298 optimizer which miscompiles the URI module. Please use another 299 compiler.</p> 300 </li> 301</ol> 302 303<h3><a name="Developer">Developer</a> corner</h3> 304<ol> 305 <li><em>Troubles compiling or linking programs using libxml2</em> 306 <p>Usually the problem comes from the fact that the compiler doesn't get 307 the right compilation or linking flags. There is a small shell script 308 <code>xml2-config</code> which is installed as part of libxml2 usual 309 install process which provides those flags. Use</p> 310 <p><code>xml2-config --cflags</code></p> 311 <p>to get the compilation flags and</p> 312 <p><code>xml2-config --libs</code></p> 313 <p>to get the linker flags. Usually this is done directly from the 314 Makefile as:</p> 315 <p><code>CFLAGS=`xml2-config --cflags`</code></p> 316 <p><code>LIBS=`xml2-config --libs`</code></p> 317 </li> 318 <li><em>I want to install my own copy of libxml2 in my home directory and link 319 my programs against it, but it doesn't work</em> 320 <p>There are many different ways to accomplish this. Here is one way to 321 do this under Linux. Suppose your home directory is <code>/home/user. 322 </code>Then:</p> 323 <ul><li>Create a subdirectory, let's call it <code>myxml</code></li> 324 <li>unpack the libxml2 distribution into that subdirectory</li> 325 <li>chdir into the unpacked distribution (<code>/home/user/myxml/libxml2 326 </code>)</li> 327 <li>configure the library using the "<code>--prefix</code>" switch, 328 specifying an installation subdirectory in <code>/home/user/myxml</code>, 329 e.g. 330 <p><code>/configure --prefix /home/user/myxml/xmlinst</code> {other 331 configuration options}</p></li> 332 <li>now run <code>make</code> followed by <code>make install</code></li> 333 <li>At this point, the installation subdirectory contains the complete 334 "private" include files, library files and binary program files (e.g. 335 xmllint), located in 336 <p> <code>/home/user/myxml/xmlinst/lib, /home/user/myxml/xmlinst/include 337 </code> and <code> /home/user/myxml/xmlinst/bin</code></p> 338 respectively.</li> 339 <li>In order to use this "private" library, you should first add it 340 to the beginning of your default PATH (so that your own private 341 program files such as xmllint will be used instead of the normal 342 system ones). To do this, the Bash command would be 343 <p><code>export PATH=/home/user/myxml/xmlinst/bin:$PATH</code></p></li> 344 <li>Now suppose you have a program <code>test1.c</code> that you would 345 like to compile with your "private" library. Simply compile it 346 using the command <p><code>gcc `xml2-config --cflags --libs` -o test 347 test.c</code></p> Note that, because your PATH has been set with <code> 348 /home/user/myxml/xmlinst/bin</code> at the beginning, the 349 xml2-config program which you just installed will be used instead of 350 the system default one, and this will <em>automatically</em> get the 351 correct libraries linked with your program.</li></ul> 352 </li><p/> 353 <li><em>xmlDocDump() generates output on one line.</em> 354 <p>Libxml2 will not <strong>invent</strong> spaces in the content of a 355 document since <strong>all spaces in the content of a document are 356 significant</strong>. If you build a tree from the API and want 357 indentation:</p> 358 <ol> 359 <li>the correct way is to generate those yourself too.</li> 360 <li>the dangerous way is to ask libxml2 to add those blanks to your 361 content <strong>modifying the content of your document in the 362 process</strong>. The result may not be what you expect. There is 363 <strong>NO</strong> way to guarantee that such a modification won't 364 affect other parts of the content of your document. See <a 365 href="http://xmlsoft.org/html/libxml-parser.html#xmlKeepBlanksDefault">xmlKeepBlanksDefault 366 ()</a> and <a 367 href="http://xmlsoft.org/html/libxml-tree.html#xmlSaveFormatFile">xmlSaveFormatFile 368 ()</a></li> 369 </ol> 370 </li> 371 <li>Extra nodes in the document: 372 <p><em>For a XML file as below:</em></p> 373 <pre><?xml version="1.0"?> 374<PLAN xmlns="http://www.argus.ca/autotest/1.0/"> 375<NODE CommFlag="0"/> 376<NODE CommFlag="1"/> 377</PLAN></pre> 378 <p><em>after parsing it with the function 379 pxmlDoc=xmlParseFile(...);</em></p> 380 <p><em>I want to the get the content of the first node (node with the 381 CommFlag="0")</em></p> 382 <p><em>so I did it as following;</em></p> 383 <pre>xmlNodePtr pnode; 384pnode=pxmlDoc->children->children;</pre> 385 <p><em>but it does not work. If I change it to</em></p> 386 <pre>pnode=pxmlDoc->children->children->next;</pre> 387 <p><em>then it works. Can someone explain it to me.</em></p> 388 <p></p> 389 <p>In XML all characters in the content of the document are significant 390 <strong>including blanks and formatting line breaks</strong>.</p> 391 <p>The extra nodes you are wondering about are just that, text nodes with 392 the formatting spaces which are part of the document but that people tend 393 to forget. There is a function <a 394 href="http://xmlsoft.org/html/libxml-parser.html">xmlKeepBlanksDefault 395 ()</a> to remove those at parse time, but that's an heuristic, and its 396 use should be limited to cases where you are certain there is no 397 mixed-content in the document.</p> 398 </li> 399 <li><em>I get compilation errors of existing code like when accessing 400 <strong>root</strong> or <strong>child fields</strong> of nodes.</em> 401 <p>You are compiling code developed for libxml version 1 and using a 402 libxml2 development environment. Either switch back to libxml v1 devel or 403 even better fix the code to compile with libxml2 (or both) by <a 404 href="upgrade.html">following the instructions</a>.</p> 405 </li> 406 <li><em>I get compilation errors about non existing 407 <strong>xmlRootNode</strong> or <strong>xmlChildrenNode</strong> 408 fields.</em> 409 <p>The source code you are using has been <a 410 href="upgrade.html">upgraded</a> to be able to compile with both libxml 411 and libxml2, but you need to install a more recent version: 412 libxml(-devel) >= 1.8.8 or libxml2(-devel) >= 2.1.0</p> 413 </li> 414 <li><em>XPath implementation looks seriously broken</em> 415 <p>XPath implementation prior to 2.3.0 was really incomplete. Upgrade to 416 a recent version, there are no known bugs in the current version.</p> 417 </li> 418 <li><em>The example provided in the web page does not compile.</em> 419 <p>It's hard to maintain the documentation in sync with the code 420 <grin/> ...</p> 421 <p>Check the previous points 1/ and 2/ raised before, and please send 422 patches.</p> 423 </li> 424 <li><em>Where can I get more examples and information than provided on the 425 web page?</em> 426 <p>Ideally a libxml2 book would be nice. I have no such plan ... But you 427 can:</p> 428 <ul> 429 <li>check more deeply the <a href="html/libxml-lib.html">existing 430 generated doc</a></li> 431 <li>have a look at <a href="examples/index.html">the set of 432 examples</a>.</li> 433 <li>look for examples of use for libxml2 function using the Gnome code. 434 For example the following will query the full Gnome CVS base for the 435 use of the <strong>xmlAddChild()</strong> function: 436 <p><a 437 href="http://cvs.gnome.org/lxr/search?string=xmlAddChild">http://cvs.gnome.org/lxr/search?string=xmlAddChild</a></p> 438 <p>This may be slow, a large hardware donation to the gnome project 439 could cure this :-)</p> 440 </li> 441 <li><a 442 href="http://cvs.gnome.org/bonsai/rview.cgi?cvsroot=/cvs/gnome&dir=gnome-xml">Browse 443 the libxml2 source</a> , I try to write code as clean and documented 444 as possible, so looking at it may be helpful. In particular the code 445 of xmllint.c and of the various testXXX.c test programs should 446 provide good examples of how to do things with the library.</li> 447 </ul> 448 </li> 449 <li>What about C++ ? 450 <p>libxml2 is written in pure C in order to allow easy reuse on a number 451 of platforms, including embedded systems. I don't intend to convert to 452 C++.</p> 453 <p>There is however a C++ wrapper which may fulfill your needs:</p> 454 <ul> 455 <li>by Ari Johnson <ari@btigate.com>: 456 <p>Website: <a 457 href="http://libxmlplusplus.sourceforge.net/">http://libxmlplusplus.sourceforge.net/</a></p> 458 <p>Download: <a 459 href="http://sourceforge.net/project/showfiles.php?group_id=12999">http://sourceforge.net/project/showfiles.php?group_id=12999</a></p> 460 </li> 461 <!-- Website is currently unavailable as of 2003-08-02 462 <li>by Peter Jones <pjones@pmade.org> 463 <p>Website: <a 464 href="http://pmade.org/pjones/software/xmlwrapp/">http://pmade.org/pjones/software/xmlwrapp/</a></p> 465 </li> 466 --> 467 </ul> 468 </li> 469 <li>How to validate a document a posteriori ? 470 <p>It is possible to validate documents which had not been validated at 471 initial parsing time or documents which have been built from scratch 472 using the API. Use the <a 473 href="http://xmlsoft.org/html/libxml-valid.html#xmlValidateDtd">xmlValidateDtd()</a> 474 function. It is also possible to simply add a DTD to an existing 475 document:</p> 476 <pre>xmlDocPtr doc; /* your existing document */ 477xmlDtdPtr dtd = xmlParseDTD(NULL, filename_of_dtd); /* parse the DTD */ 478 479 dtd->name = xmlStrDup((xmlChar*)"root_name"); /* use the given root */ 480 481 doc->intSubset = dtd; 482 if (doc->children == NULL) xmlAddChild((xmlNodePtr)doc, (xmlNodePtr)dtd); 483 else xmlAddPrevSibling(doc->children, (xmlNodePtr)dtd); 484 </pre> 485 </li> 486 <li>So what is this funky "xmlChar" used all the time? 487 <p>It is a null terminated sequence of utf-8 characters. And only utf-8! 488 You need to convert strings encoded in different ways to utf-8 before 489 passing them to the API. This can be accomplished with the iconv library 490 for instance.</p> 491 </li> 492 <li>etc ...</li> 493</ol> 494 495<p></p> 496 497<h2><a name="Documentat">Developer Menu</a></h2> 498 499<p>There are several on-line resources related to using libxml:</p> 500<ol> 501 <li>Use the <a href="search.php">search engine</a> to look up 502 information.</li> 503 <li>Check the <a href="FAQ.html">FAQ.</a></li> 504 <li>Check the <a href="http://xmlsoft.org/html/libxml-lib.html">extensive 505 documentation</a> automatically extracted from code comments.</li> 506 <li>Look at the documentation about <a href="encoding.html">libxml 507 internationalization support</a>.</li> 508 <li>This page provides a global overview and <a href="example.html">some 509 examples</a> on how to use libxml.</li> 510 <li><a href="examples/index.html">Code examples</a></li> 511 <li>John Fleck's libxml2 tutorial: <a href="tutorial/index.html">html</a> 512 or <a href="tutorial/xmltutorial.pdf">pdf</a>.</li> 513 <li>If you need to parse large files, check the <a 514 href="xmlreader.html">xmlReader</a> API tutorial</li> 515 <li><a href="mailto:james@daa.com.au">James Henstridge</a> wrote <a 516 href="http://www.daa.com.au/~james/gnome/xml-sax/xml-sax.html">some nice 517 documentation</a> explaining how to use the libxml SAX interface.</li> 518 <li>George Lebl wrote <a 519 href="http://www-106.ibm.com/developerworks/library/l-gnome3/">an article 520 for IBM developerWorks</a> about using libxml.</li> 521 <li>Check <a href="http://cvs.gnome.org/lxr/source/gnome-xml/TODO">the TODO 522 file</a>.</li> 523 <li>Read the <a href="upgrade.html">1.x to 2.x upgrade path</a> 524 description. If you are starting a new project using libxml you should 525 really use the 2.x version.</li> 526 <li>And don't forget to look at the <a 527 href="http://mail.gnome.org/archives/xml/">mailing-list archive</a>.</li> 528</ol> 529 530<h2><a name="Reporting">Reporting bugs and getting help</a></h2> 531 532<p>Well, bugs or missing features are always possible, and I will make a 533point of fixing them in a timely fashion. The best way to report a bug is to 534use the <a href="http://bugzilla.gnome.org/buglist.cgi?product=libxml2">Gnome 535bug tracking database</a> (make sure to use the "libxml2" module name). I 536look at reports there regularly and it's good to have a reminder when a bug 537is still open. Be sure to specify that the bug is for the package libxml2.</p> 538 539<p>For small problems you can try to get help on IRC, the #xml channel on 540irc.gnome.org (port 6667) usually have a few person subscribed which may help 541(but there is no garantee and if a real issue is raised it should go on the 542mailing-list for archival).</p> 543 544<p>There is also a mailing-list <a 545href="mailto:xml@gnome.org">xml@gnome.org</a> for libxml, with an <a 546href="http://mail.gnome.org/archives/xml/">on-line archive</a> (<a 547href="http://xmlsoft.org/messages">old</a>). To subscribe to this list, 548please visit the <a 549href="http://mail.gnome.org/mailman/listinfo/xml">associated Web</a> page and 550follow the instructions. <strong>Do not send code, I won't debug it</strong> 551(but patches are really appreciated!).</p> 552 553<p>Please note that with the current amount of virus and SPAM, sending mail 554to the list without being subscribed won't work. There is *far too many 555bounces* (in the order of a thousand a day !) I cannot approve them manually 556anymore. If your mail to the list bounced waiting for administrator approval, 557it is LOST ! Repost it and fix the problem triggering the error.</p> 558 559<p>Check the following <strong><span style="color: #FF0000">before 560posting</span></strong>:</p> 561<ul> 562 <li>Read the <a href="FAQ.html">FAQ</a> and <a href="search.php">use the 563 search engine</a> to get information related to your problem.</li> 564 <li>Make sure you are <a href="ftp://xmlsoft.org/">using a recent 565 version</a>, and that the problem still shows up in a recent version.</li> 566 <li>Check the <a href="http://mail.gnome.org/archives/xml/">list 567 archives</a> to see if the problem was reported already. In this case 568 there is probably a fix available, similarly check the <a 569 href="http://bugzilla.gnome.org/buglist.cgi?product=libxml2">registered 570 open bugs</a>.</li> 571 <li>Make sure you can reproduce the bug with xmllint or one of the test 572 programs found in source in the distribution.</li> 573 <li>Please send the command showing the error as well as the input (as an 574 attachment)</li> 575</ul> 576 577<p>Then send the bug with associated information to reproduce it to the <a 578href="mailto:xml@gnome.org">xml@gnome.org</a> list; if it's really libxml 579related I will approve it. Please do not send mail to me directly, it makes 580things really hard to track and in some cases I am not the best person to 581answer a given question, ask on the list.</p> 582 583<p>To <span style="color: #E50000">be really clear about support</span>:</p> 584<ul> 585 <li>Support or help <span style="color: #E50000">requests MUST be sent to 586 the list or on bugzilla</span> in case of problems, so that the Question 587 and Answers can be shared publicly. Failing to do so carries the implicit 588 message "I want free support but I don't want to share the benefits with 589 others" and is not welcome. I will automatically Carbon-Copy the 590 xml@gnome.org mailing list for any technical reply made about libxml2 or 591 libxslt.</li> 592 <li>There is <span style="color: #E50000">no garantee of support</span>, if 593 your question remains unanswered after a week, repost it, making sure you 594 gave all the detail needed and the information requested.</li> 595 <li>Failing to provide information as requested or double checking first 596 for prior feedback also carries the implicit message "the time of the 597 library maintainers is less valuable than my time" and might not be 598 welcome.</li> 599</ul> 600 601<p>Of course, bugs reported with a suggested patch for fixing them will 602probably be processed faster than those without.</p> 603 604<p>If you're looking for help, a quick look at <a 605href="http://mail.gnome.org/archives/xml/">the list archive</a> may actually 606provide the answer. I usually send source samples when answering libxml2 607usage questions. The <a 608href="http://xmlsoft.org/html/book1.html">auto-generated documentation</a> is 609not as polished as I would like (i need to learn more about DocBook), but 610it's a good starting point.</p> 611 612<h2><a name="help">How to help</a></h2> 613 614<p>You can help the project in various ways, the best thing to do first is to 615subscribe to the mailing-list as explained before, check the <a 616href="http://mail.gnome.org/archives/xml/">archives </a>and the <a 617href="http://bugzilla.gnome.org/buglist.cgi?product=libxml2">Gnome bug 618database</a>:</p> 619<ol> 620 <li>Provide patches when you find problems.</li> 621 <li>Provide the diffs when you port libxml2 to a new platform. They may not 622 be integrated in all cases but help pinpointing portability problems 623 and</li> 624 <li>Provide documentation fixes (either as patches to the code comments or 625 as HTML diffs).</li> 626 <li>Provide new documentations pieces (translations, examples, etc 627 ...).</li> 628 <li>Check the TODO file and try to close one of the items.</li> 629 <li>Take one of the points raised in the archive or the bug database and 630 provide a fix. <a href="mailto:daniel@veillard.com">Get in touch with me 631 </a>before to avoid synchronization problems and check that the suggested 632 fix will fit in nicely :-)</li> 633</ol> 634 635<h2><a name="Downloads">Downloads</a></h2> 636 637<p>The latest versions of libxml2 can be found on the <a 638href="ftp://xmlsoft.org/">xmlsoft.org</a> server ( <a 639href="http://xmlsoft.org/sources/">HTTP</a>, <a 640href="ftp://xmlsoft.org/">FTP</a> and rsync are available), there is also 641mirrors (<a href="ftp://ftp.planetmirror.com/pub/xmlsoft/">Australia</a>( <a 642href="http://xmlsoft.planetmirror.com/">Web</a>), <a 643href="ftp://fr.rpmfind.net/pub/libxml/">France</a>) or on the <a 644href="ftp://ftp.gnome.org/pub/GNOME/MIRRORS.html">Gnome FTP server</a> as <a 645href="ftp://ftp.gnome.org/pub/GNOME/sources/libxml2/2.6/">source archive</a> 646, Antonin Sprinzl also provide <a href="ftp://gd.tuwien.ac.at/pub/libxml/">a 647mirror in Austria</a>. (NOTE that you need both the <a 648href="http://rpmfind.net/linux/RPM/libxml2.html">libxml(2)</a> and <a 649href="http://rpmfind.net/linux/RPM/libxml2-devel.html">libxml(2)-devel</a> 650packages installed to compile applications using libxml.)</p> 651 652<p>You can find all the history of libxml(2) and libxslt releases in the <a 653href="http://xmlsoft.org/sources/old/">old</a> directory. The precompiled 654Windows binaries made by Igor Zlatovic are available in the <a 655href="http://xmlsoft.org/sources/win32/">win32</a> directory.</p> 656 657<p>Binary ports:</p> 658<ul> 659 <li>Red Hat RPMs for i386 are available directly on <a 660 href="ftp://xmlsoft.org/">xmlsoft.org</a>, the source RPM will compile on 661 any architecture supported by Red Hat.</li> 662 <li><a href="mailto:igor@zlatkovic.com">Igor Zlatkovic</a> is now the 663 maintainer of the Windows port, <a 664 href="http://www.zlatkovic.com/projects/libxml/index.html">he provides 665 binaries</a>.</li> 666 <li>Blastwave provides 667 <a href="http://www.blastwave.org/packages.php/libxml2">Solaris binaries</a>.</li> 668 <li><a href="mailto:Steve.Ball@explain.com.au">Steve Ball</a> provides <a 669 href="http://www.explain.com.au/oss/libxml2xslt.html">Mac Os X 670 binaries</a>.</li> 671 <li>The HP-UX porting center provides <a 672 href="http://hpux.connect.org.uk/hppd/hpux/Gnome/">HP-UX binaries</a></li> 673 <li>Bull provides precompiled <a href="http://gnome.bullfreeware.com/new_index.html">RPMs for AIX</a> as patr of their GNOME packages</li> 674</ul> 675 676<p>If you know other supported binary ports, please <a 677href="http://veillard.com/">contact me</a>.</p> 678 679<p><a name="Snapshot">Snapshot:</a></p> 680<ul> 681 <li>Code from the W3C cvs base libxml2 module, updated hourly <a 682 href="ftp://xmlsoft.org/libxml2-cvs-snapshot.tar.gz">libxml2-cvs-snapshot.tar.gz</a>.</li> 683 <li>Docs, content of the web site, the list archive included <a 684 href="ftp://xmlsoft.org/libxml-docs.tar.gz">libxml-docs.tar.gz</a>.</li> 685</ul> 686 687<p><a name="Contribs">Contributions:</a></p> 688 689<p>I do accept external contributions, especially if compiling on another 690platform, get in touch with the list to upload the package, wrappers for 691various languages have been provided, and can be found in the <a 692href="python.html">bindings section</a></p> 693 694<p>Libxml2 is also available from CVS:</p> 695<ul> 696 <li><p>The <a href="http://cvs.gnome.org/viewcvs/libxml2/">Gnome CVS 697 base</a>. Check the <a 698 href="http://developer.gnome.org/tools/cvs.html">Gnome CVS Tools</a> 699 page; the CVS module is <b>libxml2</b>.</p> 700 </li> 701 <li>The <strong>libxslt</strong> module is also present there</li> 702</ul> 703 704<h2><a name="News">Releases</a></h2> 705 706<p>Items not finished and worked on, get in touch with the list if you want 707to help those</p> 708<ul> 709 <li>More testing on RelaxNG</li> 710 <li>Finishing up <a href="http://www.w3.org/TR/xmlschema-1/">XML 711 Schemas</a></li> 712</ul> 713 714<p>The <a href="ChangeLog.html">change log</a> describes the recents commits 715to the <a href="http://cvs.gnome.org/viewcvs/libxml2/">CVS</a> code base.</p> 716 717<p>There is the list of public releases:</p> 718 719<h3>2.6.21: Sep 4 2005</h3> 720<ul> 721 <li>build fixes: Cygwin portability fixes (Gerrit P. Haase), calling 722 convention problems on Windows (Marcus Boerger), cleanups based on 723 Linus' sparse tool, update of win32/configure.js (Rob Richards), 724 remove warnings on Windows(Marcus Boerger), compilation without SAX1, 725 detection of the Python binary, use $GCC inestad of $CC = 'gcc' (Andrew 726 W. Nosenko), compilation/link with threads and old gcc, compile 727 problem by C370 on Z/OS, </li> 728 <li>bug fixes: http_proxy environments (Peter Breitenlohner), HTML UTF-8 729 bug (Jiri Netolicky), XPath NaN compare bug (William Brack), 730 htmlParseScript potential bug, Schemas regexp handling of spaces, 731 Base64 Schemas comparisons NIST passes, automata build error xsd:all, 732 xmlGetNodePath for namespaced attributes (Alexander Pohoyda), 733 xmlSchemas foreign namespaces handling, XML Schemas facet comparison 734 (Kupriyanov Anatolij), xmlSchemaPSimpleTypeErr error report (Kasimier 735 Buchcik), xml: namespace ahndling in Schemas (Kasimier), empty model 736 group in Schemas (Kasimier), wilcard in Schemas (Kasimier), URI 737 composition (William), xs:anyType in Schemas (Kasimier), Python resolver 738 emmitting error messages directly, Python xmlAttr.parent (Jakub Piotr 739 Clapa), trying to fix the file path/URI conversion, 740 xmlTextReaderGetAttribute fix (Rob Richards), xmlSchemaFreeAnnot memleak 741 (Kasimier), HTML UTF-8 serialization, streaming XPath, Schemas determinism 742 detection problem, XInclude bug, Schemas context type (Dean Hill), 743 validation fix (Derek Poon), xmlTextReaderGetAttribute[Ns] namespaces 744 (Rob Richards), Schemas type fix (Kuba Nowakowski), UTF-8 parser bug, 745 error in encoding handling, xmlGetLineNo fixes, bug on entities handling, 746 entity name extraction in error handling with XInclude, text nodes 747 in HTML body tags (Gary Coady), xml:id and IDness at the treee level 748 fixes, XPath streaming patterns bugs.</li> 749 <li>improvements: structured interfaces for schemas and RNG error reports 750 (Marcus Boerger), optimization of the char data inner loop parsing 751 (thanks to Behdad Esfahbod for the idea), schematron validation 752 though not finished yet, xmlSaveOption to omit XML declaration, 753 keyref match error reports (Kasimier), formal expression handling 754 code not plugged yet, more lax mode for the HTML parser, 755 parser XML_PARSE_COMPACT option for text nodes allocation.</li> 756 <li>documentation: xmllint man page had --nonet duplicated</li> 757</ul> 758<h3>2.6.20: Jul 10 2005</h3> 759<ul> 760 <li> build fixes: Windows build (Rob Richards), Mingw compilation (Igor 761 Zlatkovic), Windows Makefile (Igor), gcc warnings (Kasimier and 762 andriy@google.com), use gcc weak references to pthread to avoid the 763 pthread dependancy on Linux, compilation problem (Steve Nairn), 764 compiling of subset (Morten Welinder), IPv6/ss_family compilation 765 (William Brack), compilation when disabling parts of the library, 766 standalone test distribution. 767 </li> 768 <li> bug fixes: bug in lang(), memory cleanup on errors (William Brack), 769 HTTP query strings (Aron Stansvik), memory leak in DTD (William), 770 integer overflow in XPath (William), nanoftp buffer size, pattern 771 "." apth fixup (Kasimier), leak in tree reported by Malcolm Rowe, 772 replaceNode patch (Brent Hendricks), CDATA with NULL content 773 (Mark Vakoc), xml:base fixup on XInclude (William), pattern 774 fixes (William), attribute bug in exclusive c14n (Aleksey Sanin), 775 xml:space and xml:lang with SAX2 (Rob Richards), namespace 776 trouble in complex parsing (Malcolm Rowe), XSD type QNames fixes 777 (Kasimier), XPath streaming fixups (William), RelaxNG bug (Rob Richards), 778 Schemas for Schemas fixes (Kasimier), removal of ID (Rob Richards), 779 a small RelaxNG leak, HTML parsing in push mode bug (James Bursa), 780 failure to detect UTF-8 parsing bugs in CDATA sections, areBlanks() 781 heuristic failure, duplicate attributes in DTD bug (William). 782 </li> 783 <li> improvements: lot of work on Schemas by Kasimier Buchcik both on 784 conformance and streaming, Schemas validation messages (Kasimier 785 Buchcik, Matthew Burgess), namespace removal at the python level 786 (Brent Hendricks), Update to new Schemas regression tests from 787 W3C/Nist (Kasimier), xmlSchemaValidateFile() (Kasimier), implementation 788 of xmlTextReaderReadInnerXml and xmlTextReaderReadOuterXml (James Wert), 789 standalone test framework and programs, new DOM import APIs 790 xmlDOMWrapReconcileNamespaces() xmlDOMWrapAdoptNode() and 791 xmlDOMWrapRemoveNode(), extension of xmllint capabilities for 792 SAX and Schemas regression tests, xmlStopParser() available in 793 pull mode too, ienhancement to xmllint --shell namespaces support, 794 Windows port of the standalone testing tools (Kasimier and William), 795 xmlSchemaValidateStream() xmlSchemaSAXPlug() and xmlSchemaSAXUnplug() 796 SAX Schemas APIs, Schemas xmlReader support. 797 </li> 798</ul> 799<h3>2.6.19: Apr 02 2005</h3> 800<ul> 801 <li> build fixes: drop .la from RPMs, --with-minimum build fix (William 802 Brack), use XML_SOCKLEN_T instead of SOCKLEN_T because it breaks with 803 AIX 5.3 compiler, fixed elfgcchack.h generation and PLT reduction 804 code on Linux/ELF/gcc4</li> 805 <li> bug fixes: schemas type decimal fixups (William Brack), xmmlint return 806 code (Gerry Murphy), small schemas fixes (Matthew Burgess and 807 GUY Fabrice), workaround "DAV:" namespace brokeness in c14n (Aleksey 808 Sanin), segfault in Schemas (Kasimier Buchcik), Schemas attribute 809 validation (Kasimier), Prop related functions and xmlNewNodeEatName 810 (Rob Richards), HTML serialization of name attribute on a elements, 811 Python error handlers leaks and improvement (Brent Hendricks), 812 uninitialized variable in encoding code, Relax-NG validation bug, 813 potential crash if gnorableWhitespace is NULL, xmlSAXParseDoc and 814 xmlParseDoc signatures, switched back to assuming UTF-8 in case 815 no encoding is given at serialization time</li> 816 <li> improvements: lot of work on Schemas by Kasimier Buchcik on facets 817 checking and also mixed handling.</li> 818 <li></li> 819</ul> 820<h3>2.6.18: Mar 13 2005</h3> 821<ul> 822 <li> build fixes: warnings (Peter Breitenlohner), testapi.c generation, 823 Bakefile support (Francesco Montorsi), Windows compilation (Joel Reed), 824 some gcc4 fixes, HP-UX portability fixes (Rick Jones).</li> 825 <li> bug fixes: xmlSchemaElementDump namespace (Kasimier Buchcik), push and 826 xmlreader stopping on non-fatal errors, thread support for dictionnaries 827 reference counting (Gary Coady), internal subset and push problem, 828 URL saved in xmlCopyDoc, various schemas bug fixes (Kasimier), Python 829 paths fixup (Stephane Bidoul), xmlGetNodePath and namespaces, 830 xmlSetNsProp fix (Mike Hommey), warning should not count as error 831 (William Brack), xmlCreatePushParser empty chunk, XInclude parser 832 flags (William), cleanup FTP and HTTP code to reuse the uri parsing 833 and IPv6 (William), xmlTextWriterStartAttributeNS fix (Rob Richards), 834 XMLLINT_INDENT being empty (William), xmlWriter bugs (Rob Richards), 835 multithreading on Windows (Rich Salz), xmlSearchNsByHref fix (Kasimier), 836 Python binding leak (Brent Hendricks), aliasing bug exposed by gcc4 837 on s390, xmlTextReaderNext bug (Rob Richards), Schemas decimal type 838 fixes (William Brack), xmlByteConsumed static buffer (Ben Maurer).</li> 839 <li> improvement: speedup parsing comments and DTDs, dictionnary support for 840 hash tables, Schemas Identity constraints (Kasimier), streaming XPath 841 subset, xmlTextReaderReadString added (Bjorn Reese), Schemas canonical 842 values handling (Kasimier), add xmlTextReaderByteConsumed (Aron 843 Stansvik), </li> 844 <li> Documentation: Wiki support (Joel Reed) 845</ul> 846<h3>2.6.17: Jan 16 2005</h3> 847<ul> 848 <li>build fixes: Windows, warnings removal (William Brack), 849 maintainer-clean dependency(William), build in a different directory 850 (William), fixing --with-minimum configure build (William), BeOS 851 build (Marcin Konicki), Python-2.4 detection (William), compilation 852 on AIX (Dan McNichol)</li> 853 <li>bug fixes: xmlTextReaderHasAttributes (Rob Richards), xmlCtxtReadFile() 854 to use the catalog(s), loop on output (William Brack), XPath memory leak, 855 ID deallocation problem (Steve Shepard), debugDumpNode crash (William), 856 warning not using error callback (William), xmlStopParser bug (William), 857 UTF-16 with BOM on DTDs (William), namespace bug on empty elements 858 in push mode (Rob Richards), line and col computations fixups (Aleksey 859 Sanin), xmlURIEscape fix (William), xmlXPathErr on bad range (William), 860 patterns with too many steps, bug in RNG choice optimization, line 861 number sometimes missing. 862 </li> 863 <li>improvements: XSD Schemas (Kasimier Buchcik), python generator (William), 864 xmlUTF8Strpos speedup (William), unicode Python strings (William), 865 XSD error reports (Kasimier Buchcik), Python __str__ call serialize(). 866 </li> 867 <li>new APIs: added xmlDictExists(), GetLineNumber and GetColumnNumber 868 for the xmlReader (Aleksey Sanin), Dynamic Shared Libraries APIs 869 (mostly Joel Reed), error extraction API from regexps, new XMLSave 870 option for format (Phil Shafer)</li> 871 <li>documentation: site improvement (John Fleck), FAQ entries (William).</li> 872</ul> 873 874<h3>2.6.16: Nov 10 2004</h3> 875<ul> 876 <li>general hardening and bug fixing crossing all the API based on new 877 automated regression testing</li> 878 <li>build fix: IPv6 build and test on AIX (Dodji Seketeli)</li> 879 <li>bug fixes: problem with XML::Libxml reported by Petr Pajas, encoding 880 conversion functions return values, UTF-8 bug affecting XPath reported by 881 Markus Bertheau, catalog problem with NULL entries (William Brack)</li> 882 <li>documentation: fix to xmllint man page, some API function descritpion 883 were updated.</li> 884 <li>improvements: DTD validation APIs provided at the Python level (Brent 885 Hendricks) </li> 886</ul> 887 888<h3>2.6.15: Oct 27 2004</h3> 889<ul> 890 <li>security fixes on the nanoftp and nanohttp modules</li> 891 <li>build fixes: xmllint detection bug in configure, building outside the 892 source tree (Thomas Fitzsimmons)</li> 893 <li>bug fixes: HTML parser on broken ASCII chars in names (William), Python 894 paths (Malcolm Tredinnick), xmlHasNsProp and default namespace (William), 895 saving to python file objects (Malcolm Tredinnick), DTD lookup fix 896 (Malcolm), save back <group> in catalogs (William), tree build 897 fixes (DV and Rob Richards), Schemas memory bug, structured error handler 898 on Python 64bits, thread local memory deallocation, memory leak reported 899 by Volker Roth, xmlValidateDtd in the presence of an internal subset, 900 entities and _private problem (William), xmlBuildRelativeURI error 901 (William).</li> 902 <li>improvements: better XInclude error reports (William), tree debugging 903 module and tests, convenience functions at the Reader API (Graham 904 Bennett), add support for PI in the HTML parser.</li> 905</ul> 906 907<h3>2.6.14: Sep 29 2004</h3> 908<ul> 909 <li>build fixes: configure paths for xmllint and xsltproc, compilation 910 without HTML parser, compilation warning cleanups (William Brack & 911 Malcolm Tredinnick), VMS makefile update (Craig Berry),</li> 912 <li>bug fixes: xmlGetUTF8Char (William Brack), QName properties (Kasimier 913 Buchcik), XInclude testing, Notation serialization, UTF8ToISO8859x 914 transcoding (Mark Itzcovitz), lots of XML Schemas cleanup and fixes 915 (Kasimier), ChangeLog cleanup (Stepan Kasal), memory fixes (Mark Vakoc), 916 handling of failed realloc(), out of bound array adressing in Schemas 917 date handling, Python space/tabs cleanups (Malcolm Tredinnick), NMTOKENS 918 E20 validation fix (Malcolm),</li> 919 <li>improvements: added W3C XML Schemas testsuite (Kasimier Buchcik), add 920 xmlSchemaValidateOneElement (Kasimier), Python exception hierearchy 921 (Malcolm Tredinnick), Python libxml2 driver improvement (Malcolm 922 Tredinnick), Schemas support for xsi:schemaLocation, 923 xsi:noNamespaceSchemaLocation, xsi:type (Kasimier Buchcik)</li> 924</ul> 925 926<h3>2.6.13: Aug 31 2004</h3> 927<ul> 928 <li>build fixes: Windows and zlib (Igor Zlatkovic), -O flag with gcc, 929 Solaris compiler warning, fixing RPM BuildRequires,</li> 930 <li>fixes: DTD loading on Windows (Igor), Schemas error reports APIs 931 (Kasimier Buchcik), Schemas validation crash, xmlCheckUTF8 (William Brack 932 and Julius Mittenzwei), Schemas facet check (Kasimier), default namespace 933 problem (William), Schemas hexbinary empty values, encoding error could 934 genrate a serialization loop.</li> 935 <li>Improvements: Schemas validity improvements (Kasimier), added --path 936 and --load-trace options to xmllint</li> 937 <li>documentation: tutorial update (John Fleck)</li> 938</ul> 939 940<h3>2.6.12: Aug 22 2004</h3> 941<ul> 942 <li>build fixes: fix --with-minimum, elfgcchack.h fixes (Peter 943 Breitenlohner), perl path lookup (William), diff on Solaris (Albert 944 Chin), some 64bits cleanups.</li> 945 <li>Python: avoid a warning with 2.3 (William Brack), tab and space mixes 946 (William), wrapper generator fixes (William), Cygwin support (Gerrit P. 947 Haase), node wrapper fix (Marc-Antoine Parent), XML Schemas support 948 (Torkel Lyng)</li> 949 <li>Schemas: a lot of bug fixes and improvements from Kasimier Buchcik</li> 950 <li>fixes: RVT fixes (William), XPath context resets bug (William), memory 951 debug (Steve Hay), catalog white space handling (Peter Breitenlohner), 952 xmlReader state after attribute reading (William), structured error 953 handler (William), XInclude generated xml:base fixup (William), Windows 954 memory reallocation problem (Steve Hay), Out of Memory conditions 955 handling (William and Olivier Andrieu), htmlNewDoc() charset bug, 956 htmlReadMemory init (William), a posteriori validation DTD base 957 (William), notations serialization missing, xmlGetNodePath (Dodji), 958 xmlCheckUTF8 (Diego Tartara), missing line numbers on entity 959 (William)</li> 960 <li>improvements: DocBook catalog build scrip (William), xmlcatalog tool 961 (Albert Chin), xmllint --c14n option, no_proxy environment (Mike Hommey), 962 xmlParseInNodeContext() addition, extend xmllint --shell, allow XInclude 963 to not generate start/end nodes, extend xmllint --version to include CVS 964 tag (William)</li> 965 <li>documentation: web pages fixes, validity API docs fixes (William) 966 schemas API fix (Eric Haszlakiewicz), xmllint man page (John Fleck)</li> 967</ul> 968 969<h3>2.6.11: July 5 2004</h3> 970<ul> 971 <li>Schemas: a lot of changes and improvements by Kasimier Buchcik for 972 attributes, namespaces and simple types.</li> 973 <li>build fixes: --with-minimum (William Brack), some gcc cleanup 974 (William), --with-thread-alloc (William)</li> 975 <li>portability: Windows binary package change (Igor Zlatkovic), Catalog 976 path on Windows</li> 977 <li>documentation: update to the tutorial (John Fleck), xmllint return code 978 (John Fleck), man pages (Ville Skytta),</li> 979 <li>bug fixes: C14N bug serializing namespaces (Aleksey Sanin), testSAX 980 properly initialize the library (William), empty node set in XPath 981 (William), xmlSchemas errors (William), invalid charref problem pointed 982 by Morus Walter, XInclude xml:base generation (William), Relax-NG bug 983 with div processing (William), XPointer and xml:base problem(William), 984 Reader and entities, xmllint return code for schemas (William), reader 985 streaming problem (Steve Ball), DTD serialization problem (William), 986 libxml.m4 fixes (Mike Hommey), do not provide destructors as methods on 987 Python classes, xmlReader buffer bug, Python bindings memory interfaces 988 improvement (with St�phane Bidoul), Fixed the push parser to be back to 989 synchronous behaviour.</li> 990 <li>improvement: custom per-thread I/O enhancement (Rob Richards), register 991 namespace in debug shell (Stefano Debenedetti), Python based regression 992 test for non-Unix users (William), dynamically increase the number of 993 XPath extension functions in Python and fix a memory leak (Marc-Antoine 994 Parent and William)</li> 995 <li>performance: hack done with Arjan van de Ven to reduce ELF footprint 996 and generated code on Linux, plus use gcc runtime profiling to optimize 997 the code generated in the RPM packages.</li> 998</ul> 999 1000<h3>2.6.10: May 17 2004</h3> 1001<ul> 1002 <li>Web page generated for ChangeLog</li> 1003 <li>build fixes: --without-html problems, make check without make all</li> 1004 <li>portability: problem with xpath.c on Windows (MSC and Borland), memcmp 1005 vs. strncmp on Solaris, XPath tests on Windows (Mark Vakoc), C++ do not 1006 use "list" as parameter name, make tests work with Python 1.5 (Ed 1007 Davis),</li> 1008 <li>improvements: made xmlTextReaderMode public, small buffers resizing 1009 (Morten Welinder), add --maxmem option to xmllint, add 1010 xmlPopInputCallback() for Matt Sergeant, refactoring of serialization 1011 escaping, added escaping customization</li> 1012 <li>bugfixes: xsd:extension (Taihei Goi), assorted regexp bugs (William 1013 Brack), xmlReader end of stream problem, node deregistration with reader, 1014 URI escaping and filemanes, XHTML1 formatting (Nick Wellnhofer), regexp 1015 transition reduction (William), various XSD Schemas fixes (Kasimier 1016 Buchcik), XInclude fallback problem (William), weird problems with DTD 1017 (William), structured error handler callback context (William), reverse 1018 xmlEncodeSpecialChars() behaviour back to escaping '"'</li> 1019</ul> 1020 1021<h3>2.6.9: Apr 18 2004</h3> 1022<ul> 1023 <li>implement xml:id Working Draft, relaxed XPath id() checking</li> 1024 <li>bugfixes: xmlCtxtReset (Brent Hendricks), line number and CDATA (Dave 1025 Beckett), Relax-NG compilation (William Brack), Regexp patches (with 1026 William), xmlUriEscape (Mark Vakoc), a Relax-NG notAllowed problem (with 1027 William), Relax-NG name classes compares (William), XInclude duplicate 1028 fallback (William), external DTD encoding detection (William), a DTD 1029 validation bug (William), xmlReader Close() fix, recusive extention 1030 schemas</li> 1031 <li>improvements: use xmlRead* APIs in test tools (Mark Vakoc), indenting 1032 save optimization, better handle IIS broken HTTP redirect behaviour (Ian 1033 Hummel), HTML parser frameset (James Bursa), libxml2-python RPM 1034 dependancy, XML Schemas union support (Kasimier Buchcik), warning removal 1035 clanup (William), keep ChangeLog compressed when installing from RPMs</li> 1036 <li>documentation: examples and xmlDocDumpMemory docs (John Fleck), new 1037 example (load, xpath, modify, save), xmlCatalogDump() comments,</li> 1038 <li>Windows: Borland C++ builder (Eric Zurcher), work around Microsoft 1039 compiler NaN handling bug (Mark Vakoc)</li> 1040</ul> 1041 1042<h3>2.6.8: Mar 23 2004</h3> 1043<ul> 1044 <li>First step of the cleanup of the serialization code and APIs</li> 1045 <li>XML Schemas: mixed content (Adam Dickmeiss), QName handling fixes (Adam 1046 Dickmeiss), anyURI for "" (John Belmonte)</li> 1047 <li>Python: Canonicalization C14N support added (Anthony Carrico)</li> 1048 <li>xmlDocCopyNode() extension (William)</li> 1049 <li>Relax-NG: fix when processing XInclude results (William), external 1050 reference in interleave (William), missing error on <choice> 1051 failure (William), memory leak in schemas datatype facets.</li> 1052 <li>xmlWriter: patch for better DTD support (Alfred Mickautsch)</li> 1053 <li>bug fixes: xmlXPathLangFunction memory leak (Mike Hommey and William 1054 Brack), no ID errors if using HTML_PARSE_NOERROR, xmlcatalog fallbacks to 1055 URI on SYSTEM lookup failure, XInclude parse flags inheritance (William), 1056 XInclude and XPointer fixes for entities (William), XML parser bug 1057 reported by Holger Rauch, nanohttp fd leak (William), regexps char 1058 groups '-' handling (William), dictionnary reference counting problems, 1059 do not close stderr.</li> 1060 <li>performance patches from Petr Pajas</li> 1061 <li>Documentation fixes: XML_CATALOG_FILES in man pages (Mike Hommey)</li> 1062 <li>compilation and portability fixes: --without-valid, catalog cleanups 1063 (Peter Breitenlohner), MingW patch (Roland Schwingel), cross-compilation 1064 to Windows (Christophe de Vienne), --with-html-dir fixup (Julio Merino 1065 Vidal), Windows build (Eric Zurcher)</li> 1066</ul> 1067 1068<h3>2.6.7: Feb 23 2004</h3> 1069<ul> 1070 <li>documentation: tutorial updates (John Fleck), benchmark results</li> 1071 <li>xmlWriter: updates and fixes (Alfred Mickautsch, Lucas Brasilino)</li> 1072 <li>XPath optimization (Petr Pajas)</li> 1073 <li>DTD ID handling optimization</li> 1074 <li>bugfixes: xpath number with > 19 fractional (William Brack), push 1075 mode with unescaped '>' characters, fix xmllint --stream --timing, fix 1076 xmllint --memory --stream memory usage, xmlAttrSerializeTxtContent 1077 handling NULL, trying to fix Relax-NG/Perl interface.</li> 1078 <li>python: 2.3 compatibility, whitespace fixes (Malcolm Tredinnick)</li> 1079 <li>Added relaxng option to xmllint --shell</li> 1080</ul> 1081 1082<h3>2.6.6: Feb 12 2004</h3> 1083<ul> 1084 <li>nanohttp and nanoftp: buffer overflow error on URI parsing (Igor and 1085 William) reported by Yuuichi Teranishi</li> 1086 <li>bugfixes: make test and path issues, xmlWriter attribute serialization 1087 (William Brack), xmlWriter indentation (William), schemas validation 1088 (Eric Haszlakiewicz), XInclude dictionnaries issues (William and Oleg 1089 Paraschenko), XInclude empty fallback (William), HTML warnings (William), 1090 XPointer in XInclude (William), Python namespace serialization, 1091 isolat1ToUTF8 bound error (Alfred Mickautsch), output of parameter 1092 entities in internal subset (William), internal subset bug in push mode, 1093 <xs:all> fix (Alexey Sarytchev)</li> 1094 <li>Build: fix for automake-1.8 (Alexander Winston), warnings removal 1095 (Philip Ludlam), SOCKLEN_T detection fixes (Daniel Richard), fix 1096 --with-minimum configuration.</li> 1097 <li>XInclude: allow the 2001 namespace without warning.</li> 1098 <li>Documentation: missing example/index.html (John Fleck), version 1099 dependancies (John Fleck)</li> 1100 <li>reader API: structured error reporting (Steve Ball)</li> 1101 <li>Windows compilation: mingw, msys (Mikhail Grushinskiy), function 1102 prototype (Cameron Johnson), MSVC6 compiler warnings, _WINSOCKAPI_ 1103 patch</li> 1104 <li>Parsers: added xmlByteConsumed(ctxt) API to get the byte offest in 1105 input.</li> 1106</ul> 1107 1108<h3>2.6.5: Jan 25 2004</h3> 1109<ul> 1110 <li>Bugfixes: dictionnaries for schemas (William Brack), regexp segfault 1111 (William), xs:all problem (William), a number of XPointer bugfixes 1112 (William), xmllint error go to stderr, DTD validation problem with 1113 namespace, memory leak (William), SAX1 cleanup and minimal options fixes 1114 (Mark Vadoc), parser context reset on error (Shaun McCance), XPath union 1115 evaluation problem (William) , xmlReallocLoc with NULL (Aleksey Sanin), 1116 XML Schemas double free (Steve Ball), XInclude with no href, argument 1117 callbacks order for XPath callbacks (Frederic Peters)</li> 1118 <li>Documentation: python scripts (William Brack), xslt stylesheets (John 1119 Fleck), doc (Sven Zimmerman), I/O example.</li> 1120 <li>Python bindings: fixes (William), enum support (St�phane Bidoul), 1121 structured error reporting (St�phane Bidoul)</li> 1122 <li>XInclude: various fixes for conformance, problem related to dictionnary 1123 references (William & me), recursion (William)</li> 1124 <li>xmlWriter: indentation (Lucas Brasilino), memory leaks (Alfred 1125 Mickautsch),</li> 1126 <li>xmlSchemas: normalizedString datatype (John Belmonte)</li> 1127 <li>code cleanup for strings functions (William)</li> 1128 <li>Windows: compiler patches (Mark Vakoc)</li> 1129 <li>Parser optimizations, a few new XPath and dictionnary APIs for future 1130 XSLT optimizations.</li> 1131</ul> 1132 1133<h3>2.6.4: Dec 24 2003</h3> 1134<ul> 1135 <li>Windows build fixes (Igor Zlatkovic)</li> 1136 <li>Some serious XInclude problems reported by Oleg Paraschenko and</li> 1137 <li>Unix and Makefile packaging fixes (me, William Brack,</li> 1138 <li>Documentation improvements (John Fleck, William Brack), example fix 1139 (Lucas Brasilino)</li> 1140 <li>bugfixes: xmlTextReaderExpand() with xmlReaderWalker, XPath handling of 1141 NULL strings (William Brack) , API building reader or parser from 1142 filedescriptor should not close it, changed XPath sorting to be stable 1143 again (William Brack), xmlGetNodePath() generating '(null)' (William 1144 Brack), DTD validation and namespace bug (William Brack), XML Schemas 1145 double inclusion behaviour</li> 1146</ul> 1147 1148<h3>2.6.3: Dec 10 2003</h3> 1149<ul> 1150 <li>documentation updates and cleanup (DV, William Brack, John Fleck)</li> 1151 <li>added a repository of examples, examples from Aleksey Sanin, Dodji 1152 Seketeli, Alfred Mickautsch</li> 1153 <li>Windows updates: Mark Vakoc, Igor Zlatkovic, Eric Zurcher, Mingw 1154 (Kenneth Haley)</li> 1155 <li>Unicode range checking (William Brack)</li> 1156 <li>code cleanup (William Brack)</li> 1157 <li>Python bindings: doc (John Fleck), bug fixes</li> 1158 <li>UTF-16 cleanup and BOM issues (William Brack)</li> 1159 <li>bug fixes: ID and xmlReader validation, XPath (William Brack), 1160 xmlWriter (Alfred Mickautsch), hash.h inclusion problem, HTML parser 1161 (James Bursa), attribute defaulting and validation, some serialization 1162 cleanups, XML_GET_LINE macro, memory debug when using threads (William 1163 Brack), serialization of attributes and entities content, xmlWriter 1164 (Daniel Schulman)</li> 1165 <li>XInclude bugfix, new APIs and update to the last version including the 1166 namespace change.</li> 1167 <li>XML Schemas improvements: include (Robert Stepanek), import and 1168 namespace handling, fixed the regression tests troubles, added examples 1169 based on Eric van der Vlist book, regexp fixes</li> 1170 <li>preliminary pattern support for streaming (needed for schemas 1171 constraints), added xmlTextReaderPreservePattern() to collect subdocument 1172 when streaming.</li> 1173 <li>various fixes in the structured error handling</li> 1174</ul> 1175 1176<h3>2.6.2: Nov 4 2003</h3> 1177<ul> 1178 <li>XPath context unregistration fixes</li> 1179 <li>text node coalescing fixes (Mark Lilback)</li> 1180 <li>API to screate a W3C Schemas from an existing document (Steve Ball)</li> 1181 <li>BeOS patches (Marcin 'Shard' Konicki)</li> 1182 <li>xmlStrVPrintf function added (Aleksey Sanin)</li> 1183 <li>compilation fixes (Mark Vakoc)</li> 1184 <li>stdin parsing fix (William Brack)</li> 1185 <li>a posteriori DTD validation fixes</li> 1186 <li>xmlReader bug fixes: Walker fixes, python bindings</li> 1187 <li>fixed xmlStopParser() to really stop the parser and errors</li> 1188 <li>always generate line numbers when using the new xmlReadxxx 1189 functions</li> 1190 <li>added XInclude support to the xmlReader interface</li> 1191 <li>implemented XML_PARSE_NONET parser option</li> 1192 <li>DocBook XSLT processing bug fixed</li> 1193 <li>HTML serialization for <p> elements (William Brack and me)</li> 1194 <li>XPointer failure in XInclude are now handled as resource errors</li> 1195 <li>fixed xmllint --html to use the HTML serializer on output (added 1196 --xmlout to implement the previous behaviour of saving it using the XML 1197 serializer)</li> 1198</ul> 1199 1200<h3>2.6.1: Oct 28 2003</h3> 1201<ul> 1202 <li>Mostly bugfixes after the big 2.6.0 changes</li> 1203 <li>Unix compilation patches: libxml.m4 (Patrick Welche), warnings cleanup 1204 (William Brack)</li> 1205 <li>Windows compilation patches (Joachim Bauch, Stephane Bidoul, Igor 1206 Zlatkovic)</li> 1207 <li>xmlWriter bugfix (Alfred Mickautsch)</li> 1208 <li>chvalid.[ch]: couple of fixes from Stephane Bidoul</li> 1209 <li>context reset: error state reset, push parser reset (Graham 1210 Bennett)</li> 1211 <li>context reuse: generate errors if file is not readable</li> 1212 <li>defaulted attributes for element coming from internal entities 1213 (Stephane Bidoul)</li> 1214 <li>Python: tab and spaces mix (William Brack)</li> 1215 <li>Error handler could crash in DTD validation in 2.6.0</li> 1216 <li>xmlReader: do not use the document or element _private field</li> 1217 <li>testSAX.c: avoid a problem with some PIs (Massimo Morara)</li> 1218 <li>general bug fixes: mandatory encoding in text decl, serializing 1219 Document Fragment nodes, xmlSearchNs 2.6.0 problem (Kasimier Buchcik), 1220 XPath errors not reported, slow HTML parsing of large documents.</li> 1221</ul> 1222 1223<h3>2.6.0: Oct 20 2003</h3> 1224<ul> 1225 <li>Major revision release: should be API and ABI compatible but got a lot 1226 of change</li> 1227 <li>Increased the library modularity, far more options can be stripped out, 1228 a --with-minimum configuration will weight around 160KBytes</li> 1229 <li>Use per parser and per document dictionnary, allocate names and small 1230 text nodes from the dictionnary</li> 1231 <li>Switch to a SAX2 like parser rewrote most of the XML parser core, 1232 provides namespace resolution and defaulted attributes, minimize memory 1233 allocations and copies, namespace checking and specific error handling, 1234 immutable buffers, make predefined entities static structures, etc...</li> 1235 <li>rewrote all the error handling in the library, all errors can be 1236 intercepted at a structured level, with precise information 1237 available.</li> 1238 <li>New simpler and more generic XML and HTML parser APIs, allowing to 1239 easilly modify the parsing options and reuse parser context for multiple 1240 consecutive documents.</li> 1241 <li>Similar new APIs for the xmlReader, for options and reuse, provided new 1242 functions to access content as const strings, use them for Python 1243 bindings</li> 1244 <li>a lot of other smaller API improvements: xmlStrPrintf (Aleksey Sanin), 1245 Walker i.e. reader on a document tree based on Alfred Mickautsch code, 1246 make room in nodes for line numbers, reference counting and future PSVI 1247 extensions, generation of character ranges to be checked with faster 1248 algorithm (William), xmlParserMaxDepth (Crutcher Dunnavant), buffer 1249 access</li> 1250 <li>New xmlWriter API provided by Alfred Mickautsch</li> 1251 <li>Schemas: base64 support by Anthony Carrico</li> 1252 <li>Parser<->HTTP integration fix, proper processing of the Mime-Type 1253 and charset informations if available.</li> 1254 <li>Relax-NG: bug fixes including the one reported by Martijn Faassen and 1255 zeroOrMore, better error reporting.</li> 1256 <li>Python bindings (St�phane Bidoul), never use stdout for errors 1257 output</li> 1258 <li>Portability: all the headers have macros for export and calling 1259 convention definitions (Igor Zlatkovic), VMS update (Craig A. Berry), 1260 Windows: threads (Jesse Pelton), Borland compiler (Eric Zurcher, Igor), 1261 Mingw (Igor), typos (Mark Vakoc), beta version (Stephane Bidoul), 1262 warning cleanups on AIX and MIPS compilers (William Brack), BeOS (Marcin 1263 'Shard' Konicki)</li> 1264 <li>Documentation fixes and README (William Brack), search fix (William), 1265 tutorial updates (John Fleck), namespace docs (Stefan Kost)</li> 1266 <li>Bug fixes: xmlCleanupParser (Dave Beckett), threading uninitialized 1267 mutexes, HTML doctype lowercase, SAX/IO (William), compression detection 1268 and restore (William), attribute declaration in DTDs (William), namespace 1269 on attribute in HTML output (William), input filename (Rob Richards), 1270 namespace DTD validation, xmlReplaceNode (Chris Ryland), I/O callbacks 1271 (Markus Keim), CDATA serialization (Shaun McCance), xmlReader (Peter 1272 Derr), high codepoint charref like &#x10FFFF;, buffer access in push 1273 mode (Justin Fletcher), TLS threads on Windows (Jesse Pelton), XPath bug 1274 (William), xmlCleanupParser (Marc Liyanage), CDATA output (William), HTTP 1275 error handling.</li> 1276 <li>xmllint options: --dtdvalidfpi for Tobias Reif, --sax1 for compat 1277 testing, --nodict for building without tree dictionnary, --nocdata to 1278 replace CDATA by text, --nsclean to remove surperfluous namespace 1279 declarations</li> 1280 <li>added xml2-config --libtool-libs option from Kevin P. Fleming</li> 1281 <li>a lot of profiling and tuning of the code, speedup patch for 1282 xmlSearchNs() by Luca Padovani. The xmlReader should do far less 1283 allocation and it speed should get closer to SAX. Chris Anderson worked 1284 on speeding and cleaning up repetitive checking code.</li> 1285 <li>cleanup of "make tests"</li> 1286 <li>libxml-2.0-uninstalled.pc from Malcolm Tredinnick</li> 1287 <li>deactivated the broken docBook SGML parser code and plugged the XML 1288 parser instead.</li> 1289</ul> 1290 1291<h3>2.5.11: Sep 9 2003</h3> 1292 1293<p>A bugfix only release:</p> 1294<ul> 1295 <li>risk of crash in Relax-NG</li> 1296 <li>risk of crash when using multithreaded programs</li> 1297</ul> 1298 1299<h3>2.5.10: Aug 15 2003</h3> 1300 1301<p>A bugfixes only release</p> 1302<ul> 1303 <li>Windows Makefiles (William Brack)</li> 1304 <li>UTF-16 support fixes (Mark Itzcovitz)</li> 1305 <li>Makefile and portability (William Brack) automake, Linux alpha, Mingw 1306 on Windows (Mikhail Grushinskiy)</li> 1307 <li>HTML parser (Oliver Stoeneberg)</li> 1308 <li>XInclude performance problem reported by Kevin Ruscoe</li> 1309 <li>XML parser performance problem reported by Grant Goodale</li> 1310 <li>xmlSAXParseDTD() bug fix from Malcolm Tredinnick</li> 1311 <li>and a couple other cleanup</li> 1312</ul> 1313 1314<h3>2.5.9: Aug 9 2003</h3> 1315<ul> 1316 <li>bugfixes: IPv6 portability, xmlHasNsProp (Markus Keim), Windows build 1317 (Wiliam Brake, Jesse Pelton, Igor), Schemas (Peter Sobisch), threading 1318 (Rob Richards), hexBinary type (), UTF-16 BOM (Dodji Seketeli), 1319 xmlReader, Relax-NG schemas compilation, namespace handling, EXSLT (Sean 1320 Griffin), HTML parsing problem (William Brack), DTD validation for mixed 1321 content + namespaces, HTML serialization, library initialization, 1322 progressive HTML parser</li> 1323 <li>better interfaces for Relax-NG error handling (Joachim Bauch, )</li> 1324 <li>adding xmlXIncludeProcessTree() for XInclud'ing in a subtree</li> 1325 <li>doc fixes and improvements (John Fleck)</li> 1326 <li>configure flag for -with-fexceptions when embedding in C++</li> 1327 <li>couple of new UTF-8 helper functions (William Brack)</li> 1328 <li>general encoding cleanup + ISO-8859-x without iconv (Peter Jacobi)</li> 1329 <li>xmlTextReader cleanup + enum for node types (Bjorn Reese)</li> 1330 <li>general compilation/warning cleanup Solaris/HP-UX/... (William 1331 Brack)</li> 1332</ul> 1333 1334<h3>2.5.8: Jul 6 2003</h3> 1335<ul> 1336 <li>bugfixes: XPath, XInclude, file/URI mapping, UTF-16 save (Mark 1337 Itzcovitz), UTF-8 checking, URI saving, error printing (William Brack), 1338 PI related memleak, compilation without schemas or without xpath (Joerg 1339 Schmitz-Linneweber/Garry Pennington), xmlUnlinkNode problem with DTDs, 1340 rpm problem on , i86_64, removed a few compilation problems from 2.5.7, 1341 xmlIOParseDTD, and xmlSAXParseDTD (Malcolm Tredinnick)</li> 1342 <li>portability: DJGPP (MsDos) , OpenVMS (Craig A. Berry)</li> 1343 <li>William Brack fixed multithreading lock problems</li> 1344 <li>IPv6 patch for FTP and HTTP accesses (Archana Shah/Wipro)</li> 1345 <li>Windows fixes (Igor Zlatkovic, Eric Zurcher), threading (St�phane 1346 Bidoul)</li> 1347 <li>A few W3C Schemas Structure improvements</li> 1348 <li>W3C Schemas Datatype improvements (Charlie Bozeman)</li> 1349 <li>Python bindings for thread globals (St�phane Bidoul), and method/class 1350 generator</li> 1351 <li>added --nonet option to xmllint</li> 1352 <li>documentation improvements (John Fleck)</li> 1353</ul> 1354 1355<h3>2.5.7: Apr 25 2003</h3> 1356<ul> 1357 <li>Relax-NG: Compiling to regexp and streaming validation on top of the 1358 xmlReader interface, added to xmllint --stream</li> 1359 <li>xmlReader: Expand(), Next() and DOM access glue, bug fixes</li> 1360 <li>Support for large files: RGN validated a 4.5GB instance</li> 1361 <li>Thread support is now configured in by default</li> 1362 <li>Fixes: update of the Trio code (Bjorn), WXS Date and Duration fixes 1363 (Charles Bozeman), DTD and namespaces (Brent Hendricks), HTML push parser 1364 and zero bytes handling, some missing Windows file path conversions, 1365 behaviour of the parser and validator in the presence of "out of memory" 1366 error conditions</li> 1367 <li>extended the API to be able to plug a garbage collecting memory 1368 allocator, added xmlMallocAtomic() and modified the allocations 1369 accordingly.</li> 1370 <li>Performances: removed excessive malloc() calls, speedup of the push and 1371 xmlReader interfaces, removed excessive thread locking</li> 1372 <li>Documentation: man page (John Fleck), xmlReader documentation</li> 1373 <li>Python: adding binding for xmlCatalogAddLocal (Brent M Hendricks)</li> 1374</ul> 1375 1376<h3>2.5.6: Apr 1 2003</h3> 1377<ul> 1378 <li>Fixed W3C XML Schemas datatype, should be compliant now except for 1379 binHex and base64 which are not supported yet.</li> 1380 <li>bug fixes: non-ASCII IDs, HTML output, XInclude on large docs and 1381 XInclude entities handling, encoding detection on external subsets, XML 1382 Schemas bugs and memory leaks, HTML parser (James Bursa)</li> 1383 <li>portability: python/trio (Albert Chin), Sun compiler warnings</li> 1384 <li>documentation: added --relaxng option to xmllint man page (John)</li> 1385 <li>improved error reporting: xml:space, start/end tag mismatches, Relax NG 1386 errors</li> 1387</ul> 1388 1389<h3>2.5.5: Mar 24 2003</h3> 1390<ul> 1391 <li>Lot of fixes on the Relax NG implementation. More testing including 1392 DocBook and TEI examples.</li> 1393 <li>Increased the support for W3C XML Schemas datatype</li> 1394 <li>Several bug fixes in the URI handling layer</li> 1395 <li>Bug fixes: HTML parser, xmlReader, DTD validation, XPath, encoding 1396 conversion, line counting in the parser.</li> 1397 <li>Added support for $XMLLINT_INDENT environment variable, FTP delete</li> 1398 <li>Fixed the RPM spec file name</li> 1399</ul> 1400 1401<h3>2.5.4: Feb 20 2003</h3> 1402<ul> 1403 <li>Conformance testing and lot of fixes on Relax NG and XInclude 1404 implementation</li> 1405 <li>Implementation of XPointer element() scheme</li> 1406 <li>Bug fixes: XML parser, XInclude entities merge, validity checking on 1407 namespaces, 1408 <p>2 serialization bugs, node info generation problems, a DTD regexp 1409 generation problem.</p> 1410 </li> 1411 <li>Portability: windows updates and path canonicalization (Igor)</li> 1412 <li>A few typo fixes (Kjartan Maraas)</li> 1413 <li>Python bindings generator fixes (Stephane Bidoul)</li> 1414</ul> 1415 1416<h3>2.5.3: Feb 10 2003</h3> 1417<ul> 1418 <li>RelaxNG and XML Schemas datatypes improvements, and added a first 1419 version of RelaxNG Python bindings</li> 1420 <li>Fixes: XLink (Sean Chittenden), XInclude (Sean Chittenden), API fix for 1421 serializing namespace nodes, encoding conversion bug, XHTML1 1422 serialization</li> 1423 <li>Portability fixes: Windows (Igor), AMD 64bits RPM spec file</li> 1424</ul> 1425 1426<h3>2.5.2: Feb 5 2003</h3> 1427<ul> 1428 <li>First implementation of RelaxNG, added --relaxng flag to xmllint</li> 1429 <li>Schemas support now compiled in by default.</li> 1430 <li>Bug fixes: DTD validation, namespace checking, XInclude and entities, 1431 delegateURI in XML Catalogs, HTML parser, XML reader (St�phane Bidoul), 1432 XPath parser and evaluation, UTF8ToUTF8 serialization, XML reader memory 1433 consumption, HTML parser, HTML serialization in the presence of 1434 namespaces</li> 1435 <li>added an HTML API to check elements and attributes.</li> 1436 <li>Documentation improvement, PDF for the tutorial (John Fleck), doc 1437 patches (Stefan Kost)</li> 1438 <li>Portability fixes: NetBSD (Julio Merino), Windows (Igor Zlatkovic)</li> 1439 <li>Added python bindings for XPointer, contextual error reporting 1440 (St�phane Bidoul)</li> 1441 <li>URI/file escaping problems (Stefano Zacchiroli)</li> 1442</ul> 1443 1444<h3>2.5.1: Jan 8 2003</h3> 1445<ul> 1446 <li>Fixes a memory leak and configuration/compilation problems in 2.5.0</li> 1447 <li>documentation updates (John)</li> 1448 <li>a couple of XmlTextReader fixes</li> 1449</ul> 1450 1451<h3>2.5.0: Jan 6 2003</h3> 1452<ul> 1453 <li>New <a href="xmlreader.html">XmltextReader interface</a> based on C# 1454 API (with help of St�phane Bidoul)</li> 1455 <li>Windows: more exports, including the new API (Igor)</li> 1456 <li>XInclude fallback fix</li> 1457 <li>Python: bindings for the new API, packaging (St�phane Bidoul), 1458 drv_libxml2.py Python xml.sax driver (St�phane Bidoul), fixes, speedup 1459 and iterators for Python-2.2 (Hannu Krosing)</li> 1460 <li>Tutorial fixes (john Fleck and Niraj Tolia) xmllint man update 1461 (John)</li> 1462 <li>Fix an XML parser bug raised by Vyacheslav Pindyura</li> 1463 <li>Fix for VMS serialization (Nigel Hall) and config (Craig A. Berry)</li> 1464 <li>Entities handling fixes</li> 1465 <li>new API to optionally track node creation and deletion (Lukas 1466 Schroeder)</li> 1467 <li>Added documentation for the XmltextReader interface and some <a 1468 href="guidelines.html">XML guidelines</a></li> 1469</ul> 1470 1471<h3>2.4.30: Dec 12 2002</h3> 1472<ul> 1473 <li>2.4.29 broke the python bindings, rereleasing</li> 1474 <li>Improvement/fixes of the XML API generator, and couple of minor code 1475 fixes.</li> 1476</ul> 1477 1478<h3>2.4.29: Dec 11 2002</h3> 1479<ul> 1480 <li>Windows fixes (Igor): Windows CE port, pthread linking, python bindings 1481 (St�phane Bidoul), Mingw (Magnus Henoch), and export list updates</li> 1482 <li>Fix for prev in python bindings (ERDI Gergo)</li> 1483 <li>Fix for entities handling (Marcus Clarke)</li> 1484 <li>Refactored the XML and HTML dumps to a single code path, fixed XHTML1 1485 dump</li> 1486 <li>Fix for URI parsing when handling URNs with fragment identifiers</li> 1487 <li>Fix for HTTP URL escaping problem</li> 1488 <li>added an TextXmlReader (C#) like API (work in progress)</li> 1489 <li>Rewrote the API in XML generation script, includes a C parser and saves 1490 more informations needed for C# bindings</li> 1491</ul> 1492 1493<h3>2.4.28: Nov 22 2002</h3> 1494<ul> 1495 <li>a couple of python binding fixes</li> 1496 <li>2 bug fixes in the XML push parser</li> 1497 <li>potential memory leak removed (Martin Stoilov)</li> 1498 <li>fix to the configure script for Unix (Dimitri Papadopoulos)</li> 1499 <li>added encoding support for XInclude parse="text"</li> 1500 <li>autodetection of XHTML1 and specific serialization rules added</li> 1501 <li>nasty threading bug fixed (William Brack)</li> 1502</ul> 1503 1504<h3>2.4.27: Nov 17 2002</h3> 1505<ul> 1506 <li>fixes for the Python bindings</li> 1507 <li>a number of bug fixes: SGML catalogs, xmlParseBalancedChunkMemory(), 1508 HTML parser, Schemas (Charles Bozeman), document fragment support 1509 (Christian Glahn), xmlReconciliateNs (Brian Stafford), XPointer, 1510 xmlFreeNode(), xmlSAXParseMemory (Peter Jones), xmlGetNodePath (Petr 1511 Pajas), entities processing</li> 1512 <li>added grep to xmllint --shell</li> 1513 <li>VMS update patch from Craig A. Berry</li> 1514 <li>cleanup of the Windows build with support for more compilers (Igor), 1515 better thread support on Windows</li> 1516 <li>cleanup of Unix Makefiles and spec file</li> 1517 <li>Improvements to the documentation (John Fleck)</li> 1518</ul> 1519 1520<h3>2.4.26: Oct 18 2002</h3> 1521<ul> 1522 <li>Patches for Windows CE port, improvements on Windows paths handling</li> 1523 <li>Fixes to the validation code (DTD and Schemas), xmlNodeGetPath() , 1524 HTML serialization, Namespace compliance, and a number of small 1525 problems</li> 1526</ul> 1527 1528<h3>2.4.25: Sep 26 2002</h3> 1529<ul> 1530 <li>A number of bug fixes: XPath, validation, Python bindings, DOM and 1531 tree, xmlI/O, Html</li> 1532 <li>Serious rewrite of XInclude</li> 1533 <li>Made XML Schemas regexp part of the default build and APIs, small fix 1534 and improvement of the regexp core</li> 1535 <li>Changed the validation code to reuse XML Schemas regexp APIs</li> 1536 <li>Better handling of Windows file paths, improvement of Makefiles (Igor, 1537 Daniel Gehriger, Mark Vakoc)</li> 1538 <li>Improved the python I/O bindings, the tests, added resolver and regexp 1539 APIs</li> 1540 <li>New logos from Marc Liyanage</li> 1541 <li>Tutorial improvements: John Fleck, Christopher Harris</li> 1542 <li>Makefile: Fixes for AMD x86_64 (Mandrake), DESTDIR (Christophe 1543 Merlet)</li> 1544 <li>removal of all stderr/perror use for error reporting</li> 1545 <li>Better error reporting: XPath and DTD validation</li> 1546 <li>update of the trio portability layer (Bjorn Reese)</li> 1547</ul> 1548 1549<p><strong>2.4.24: Aug 22 2002</strong></p> 1550<ul> 1551 <li>XPath fixes (William), xf:escape-uri() (Wesley Terpstra)</li> 1552 <li>Python binding fixes: makefiles (William), generator, rpm build, x86-64 1553 (fcrozat)</li> 1554 <li>HTML <style> and boolean attributes serializer fixes</li> 1555 <li>C14N improvements by Aleksey</li> 1556 <li>doc cleanups: Rick Jones</li> 1557 <li>Windows compiler makefile updates: Igor and Elizabeth Barham</li> 1558 <li>XInclude: implementation of fallback and xml:base fixup added</li> 1559</ul> 1560 1561<h3>2.4.23: July 6 2002</h3> 1562<ul> 1563 <li>performances patches: Peter Jacobi</li> 1564 <li>c14n fixes, testsuite and performances: Aleksey Sanin</li> 1565 <li>added xmlDocFormatDump: Chema Celorio</li> 1566 <li>new tutorial: John Fleck</li> 1567 <li>new hash functions and performances: Sander Vesik, portability fix from 1568 Peter Jacobi</li> 1569 <li>a number of bug fixes: XPath (William Brack, Richard Jinks), XML and 1570 HTML parsers, ID lookup function</li> 1571 <li>removal of all remaining sprintf: Aleksey Sanin</li> 1572</ul> 1573 1574<h3>2.4.22: May 27 2002</h3> 1575<ul> 1576 <li>a number of bug fixes: configure scripts, base handling, parser, memory 1577 usage, HTML parser, XPath, documentation (Christian Cornelssen), 1578 indentation, URI parsing</li> 1579 <li>Optimizations for XMLSec, fixing and making public some of the network 1580 protocol handlers (Aleksey)</li> 1581 <li>performance patch from Gary Pennington</li> 1582 <li>Charles Bozeman provided date and time support for XML Schemas 1583 datatypes</li> 1584</ul> 1585 1586<h3>2.4.21: Apr 29 2002</h3> 1587 1588<p>This release is both a bug fix release and also contains the early XML 1589Schemas <a href="http://www.w3.org/TR/xmlschema-1/">structures</a> and <a 1590href="http://www.w3.org/TR/xmlschema-2/">datatypes</a> code, beware, all 1591interfaces are likely to change, there is huge holes, it is clearly a work in 1592progress and don't even think of putting this code in a production system, 1593it's actually not compiled in by default. The real fixes are:</p> 1594<ul> 1595 <li>a couple of bugs or limitations introduced in 2.4.20</li> 1596 <li>patches for Borland C++ and MSC by Igor</li> 1597 <li>some fixes on XPath strings and conformance patches by Richard 1598 Jinks</li> 1599 <li>patch from Aleksey for the ExcC14N specification</li> 1600 <li>OSF/1 bug fix by Bjorn</li> 1601</ul> 1602 1603<h3>2.4.20: Apr 15 2002</h3> 1604<ul> 1605 <li>bug fixes: file descriptor leak, XPath, HTML output, DTD validation</li> 1606 <li>XPath conformance testing by Richard Jinks</li> 1607 <li>Portability fixes: Solaris, MPE/iX, Windows, OSF/1, python bindings, 1608 libxml.m4</li> 1609</ul> 1610 1611<h3>2.4.19: Mar 25 2002</h3> 1612<ul> 1613 <li>bug fixes: half a dozen XPath bugs, Validation, ISO-Latin to UTF8 1614 encoder</li> 1615 <li>portability fixes in the HTTP code</li> 1616 <li>memory allocation checks using valgrind, and profiling tests</li> 1617 <li>revamp of the Windows build and Makefiles</li> 1618</ul> 1619 1620<h3>2.4.18: Mar 18 2002</h3> 1621<ul> 1622 <li>bug fixes: tree, SAX, canonicalization, validation, portability, 1623 XPath</li> 1624 <li>removed the --with-buffer option it was becoming unmaintainable</li> 1625 <li>serious cleanup of the Python makefiles</li> 1626 <li>speedup patch to XPath very effective for DocBook stylesheets</li> 1627 <li>Fixes for Windows build, cleanup of the documentation</li> 1628</ul> 1629 1630<h3>2.4.17: Mar 8 2002</h3> 1631<ul> 1632 <li>a lot of bug fixes, including "namespace nodes have no parents in 1633 XPath"</li> 1634 <li>fixed/improved the Python wrappers, added more examples and more 1635 regression tests, XPath extension functions can now return node-sets</li> 1636 <li>added the XML Canonicalization support from Aleksey Sanin</li> 1637</ul> 1638 1639<h3>2.4.16: Feb 20 2002</h3> 1640<ul> 1641 <li>a lot of bug fixes, most of them were triggered by the XML Testsuite 1642 from OASIS and W3C. Compliance has been significantly improved.</li> 1643 <li>a couple of portability fixes too.</li> 1644</ul> 1645 1646<h3>2.4.15: Feb 11 2002</h3> 1647<ul> 1648 <li>Fixed the Makefiles, especially the python module ones</li> 1649 <li>A few bug fixes and cleanup</li> 1650 <li>Includes cleanup</li> 1651</ul> 1652 1653<h3>2.4.14: Feb 8 2002</h3> 1654<ul> 1655 <li>Change of License to the <a 1656 href="http://www.opensource.org/licenses/mit-license.html">MIT 1657 License</a> basically for integration in XFree86 codebase, and removing 1658 confusion around the previous dual-licensing</li> 1659 <li>added Python bindings, beta software but should already be quite 1660 complete</li> 1661 <li>a large number of fixes and cleanups, especially for all tree 1662 manipulations</li> 1663 <li>cleanup of the headers, generation of a reference API definition in 1664 XML</li> 1665</ul> 1666 1667<h3>2.4.13: Jan 14 2002</h3> 1668<ul> 1669 <li>update of the documentation: John Fleck and Charlie Bozeman</li> 1670 <li>cleanup of timing code from Justin Fletcher</li> 1671 <li>fixes for Windows and initial thread support on Win32: Igor and Serguei 1672 Narojnyi</li> 1673 <li>Cygwin patch from Robert Collins</li> 1674 <li>added xmlSetEntityReferenceFunc() for Keith Isdale work on xsldbg</li> 1675</ul> 1676 1677<h3>2.4.12: Dec 7 2001</h3> 1678<ul> 1679 <li>a few bug fixes: thread (Gary Pennington), xmllint (Geert Kloosterman), 1680 XML parser (Robin Berjon), XPointer (Danny Jamshy), I/O cleanups 1681 (robert)</li> 1682 <li>Eric Lavigne contributed project files for MacOS</li> 1683 <li>some makefiles cleanups</li> 1684</ul> 1685 1686<h3>2.4.11: Nov 26 2001</h3> 1687<ul> 1688 <li>fixed a couple of errors in the includes, fixed a few bugs, some code 1689 cleanups</li> 1690 <li>xmllint man pages improvement by Heiko Rupp</li> 1691 <li>updated VMS build instructions from John A Fotheringham</li> 1692 <li>Windows Makefiles updates from Igor</li> 1693</ul> 1694 1695<h3>2.4.10: Nov 10 2001</h3> 1696<ul> 1697 <li>URI escaping fix (Joel Young)</li> 1698 <li>added xmlGetNodePath() (for paths or XPointers generation)</li> 1699 <li>Fixes namespace handling problems when using DTD and validation</li> 1700 <li>improvements on xmllint: Morus Walter patches for --format and 1701 --encode, Stefan Kost and Heiko Rupp improvements on the --shell</li> 1702 <li>fixes for xmlcatalog linking pointed by Weiqi Gao</li> 1703 <li>fixes to the HTML parser</li> 1704</ul> 1705 1706<h3>2.4.9: Nov 6 2001</h3> 1707<ul> 1708 <li>fixes more catalog bugs</li> 1709 <li>avoid a compilation problem, improve xmlGetLineNo()</li> 1710</ul> 1711 1712<h3>2.4.8: Nov 4 2001</h3> 1713<ul> 1714 <li>fixed SGML catalogs broken in previous release, updated xmlcatalog 1715 tool</li> 1716 <li>fixed a compile errors and some includes troubles.</li> 1717</ul> 1718 1719<h3>2.4.7: Oct 30 2001</h3> 1720<ul> 1721 <li>exported some debugging interfaces</li> 1722 <li>serious rewrite of the catalog code</li> 1723 <li>integrated Gary Pennington thread safety patch, added configure option 1724 and regression tests</li> 1725 <li>removed an HTML parser bug</li> 1726 <li>fixed a couple of potentially serious validation bugs</li> 1727 <li>integrated the SGML DocBook support in xmllint</li> 1728 <li>changed the nanoftp anonymous login passwd</li> 1729 <li>some I/O cleanup and a couple of interfaces for Perl wrapper</li> 1730 <li>general bug fixes</li> 1731 <li>updated xmllint man page by John Fleck</li> 1732 <li>some VMS and Windows updates</li> 1733</ul> 1734 1735<h3>2.4.6: Oct 10 2001</h3> 1736<ul> 1737 <li>added an updated man pages by John Fleck</li> 1738 <li>portability and configure fixes</li> 1739 <li>an infinite loop on the HTML parser was removed (William)</li> 1740 <li>Windows makefile patches from Igor</li> 1741 <li>fixed half a dozen bugs reported for libxml or libxslt</li> 1742 <li>updated xmlcatalog to be able to modify SGML super catalogs</li> 1743</ul> 1744 1745<h3>2.4.5: Sep 14 2001</h3> 1746<ul> 1747 <li>Remove a few annoying bugs in 2.4.4</li> 1748 <li>forces the HTML serializer to output decimal charrefs since some 1749 version of Netscape can't handle hexadecimal ones</li> 1750</ul> 1751 1752<h3>1.8.16: Sep 14 2001</h3> 1753<ul> 1754 <li>maintenance release of the old libxml1 branch, couple of bug and 1755 portability fixes</li> 1756</ul> 1757 1758<h3>2.4.4: Sep 12 2001</h3> 1759<ul> 1760 <li>added --convert to xmlcatalog, bug fixes and cleanups of XML 1761 Catalog</li> 1762 <li>a few bug fixes and some portability changes</li> 1763 <li>some documentation cleanups</li> 1764</ul> 1765 1766<h3>2.4.3: Aug 23 2001</h3> 1767<ul> 1768 <li>XML Catalog support see the doc</li> 1769 <li>New NaN/Infinity floating point code</li> 1770 <li>A few bug fixes</li> 1771</ul> 1772 1773<h3>2.4.2: Aug 15 2001</h3> 1774<ul> 1775 <li>adds xmlLineNumbersDefault() to control line number generation</li> 1776 <li>lot of bug fixes</li> 1777 <li>the Microsoft MSC projects files should now be up to date</li> 1778 <li>inheritance of namespaces from DTD defaulted attributes</li> 1779 <li>fixes a serious potential security bug</li> 1780 <li>added a --format option to xmllint</li> 1781</ul> 1782 1783<h3>2.4.1: July 24 2001</h3> 1784<ul> 1785 <li>possibility to keep line numbers in the tree</li> 1786 <li>some computation NaN fixes</li> 1787 <li>extension of the XPath API</li> 1788 <li>cleanup for alpha and ia64 targets</li> 1789 <li>patch to allow saving through HTTP PUT or POST</li> 1790</ul> 1791 1792<h3>2.4.0: July 10 2001</h3> 1793<ul> 1794 <li>Fixed a few bugs in XPath, validation, and tree handling.</li> 1795 <li>Fixed XML Base implementation, added a couple of examples to the 1796 regression tests</li> 1797 <li>A bit of cleanup</li> 1798</ul> 1799 1800<h3>2.3.14: July 5 2001</h3> 1801<ul> 1802 <li>fixed some entities problems and reduce memory requirement when 1803 substituting them</li> 1804 <li>lots of improvements in the XPath queries interpreter can be 1805 substantially faster</li> 1806 <li>Makefiles and configure cleanups</li> 1807 <li>Fixes to XPath variable eval, and compare on empty node set</li> 1808 <li>HTML tag closing bug fixed</li> 1809 <li>Fixed an URI reference computation problem when validating</li> 1810</ul> 1811 1812<h3>2.3.13: June 28 2001</h3> 1813<ul> 1814 <li>2.3.12 configure.in was broken as well as the push mode XML parser</li> 1815 <li>a few more fixes for compilation on Windows MSC by Yon Derek</li> 1816</ul> 1817 1818<h3>1.8.14: June 28 2001</h3> 1819<ul> 1820 <li>Zbigniew Chyla gave a patch to use the old XML parser in push mode</li> 1821 <li>Small Makefile fix</li> 1822</ul> 1823 1824<h3>2.3.12: June 26 2001</h3> 1825<ul> 1826 <li>lots of cleanup</li> 1827 <li>a couple of validation fix</li> 1828 <li>fixed line number counting</li> 1829 <li>fixed serious problems in the XInclude processing</li> 1830 <li>added support for UTF8 BOM at beginning of entities</li> 1831 <li>fixed a strange gcc optimizer bugs in xpath handling of float, gcc-3.0 1832 miscompile uri.c (William), Thomas Leitner provided a fix for the 1833 optimizer on Tru64</li> 1834 <li>incorporated Yon Derek and Igor Zlatkovic fixes and improvements for 1835 compilation on Windows MSC</li> 1836 <li>update of libxml-doc.el (Felix Natter)</li> 1837 <li>fixed 2 bugs in URI normalization code</li> 1838</ul> 1839 1840<h3>2.3.11: June 17 2001</h3> 1841<ul> 1842 <li>updates to trio, Makefiles and configure should fix some portability 1843 problems (alpha)</li> 1844 <li>fixed some HTML serialization problems (pre, script, and block/inline 1845 handling), added encoding aware APIs, cleanup of this code</li> 1846 <li>added xmlHasNsProp()</li> 1847 <li>implemented a specific PI for encoding support in the DocBook SGML 1848 parser</li> 1849 <li>some XPath fixes (-Infinity, / as a function parameter and namespaces 1850 node selection)</li> 1851 <li>fixed a performance problem and an error in the validation code</li> 1852 <li>fixed XInclude routine to implement the recursive behaviour</li> 1853 <li>fixed xmlFreeNode problem when libxml is included statically twice</li> 1854 <li>added --version to xmllint for bug reports</li> 1855</ul> 1856 1857<h3>2.3.10: June 1 2001</h3> 1858<ul> 1859 <li>fixed the SGML catalog support</li> 1860 <li>a number of reported bugs got fixed, in XPath, iconv detection, 1861 XInclude processing</li> 1862 <li>XPath string function should now handle unicode correctly</li> 1863</ul> 1864 1865<h3>2.3.9: May 19 2001</h3> 1866 1867<p>Lots of bugfixes, and added a basic SGML catalog support:</p> 1868<ul> 1869 <li>HTML push bugfix #54891 and another patch from Jonas Borgstr�m</li> 1870 <li>some serious speed optimization again</li> 1871 <li>some documentation cleanups</li> 1872 <li>trying to get better linking on Solaris (-R)</li> 1873 <li>XPath API cleanup from Thomas Broyer</li> 1874 <li>Validation bug fixed #54631, added a patch from Gary Pennington, fixed 1875 xmlValidGetValidElements()</li> 1876 <li>Added an INSTALL file</li> 1877 <li>Attribute removal added to API: #54433</li> 1878 <li>added a basic support for SGML catalogs</li> 1879 <li>fixed xmlKeepBlanksDefault(0) API</li> 1880 <li>bugfix in xmlNodeGetLang()</li> 1881 <li>fixed a small configure portability problem</li> 1882 <li>fixed an inversion of SYSTEM and PUBLIC identifier in HTML document</li> 1883</ul> 1884 1885<h3>1.8.13: May 14 2001</h3> 1886<ul> 1887 <li>bugfixes release of the old libxml1 branch used by Gnome</li> 1888</ul> 1889 1890<h3>2.3.8: May 3 2001</h3> 1891<ul> 1892 <li>Integrated an SGML DocBook parser for the Gnome project</li> 1893 <li>Fixed a few things in the HTML parser</li> 1894 <li>Fixed some XPath bugs raised by XSLT use, tried to fix the floating 1895 point portability issue</li> 1896 <li>Speed improvement (8M/s for SAX, 3M/s for DOM, 1.5M/s for 1897 DOM+validation using the XML REC as input and a 700MHz celeron).</li> 1898 <li>incorporated more Windows cleanup</li> 1899 <li>added xmlSaveFormatFile()</li> 1900 <li>fixed problems in copying nodes with entities references (gdome)</li> 1901 <li>removed some troubles surrounding the new validation module</li> 1902</ul> 1903 1904<h3>2.3.7: April 22 2001</h3> 1905<ul> 1906 <li>lots of small bug fixes, corrected XPointer</li> 1907 <li>Non deterministic content model validation support</li> 1908 <li>added xmlDocCopyNode for gdome2</li> 1909 <li>revamped the way the HTML parser handles end of tags</li> 1910 <li>XPath: corrections of namespaces support and number formatting</li> 1911 <li>Windows: Igor Zlatkovic patches for MSC compilation</li> 1912 <li>HTML output fixes from P C Chow and William M. Brack</li> 1913 <li>Improved validation speed sensible for DocBook</li> 1914 <li>fixed a big bug with ID declared in external parsed entities</li> 1915 <li>portability fixes, update of Trio from Bjorn Reese</li> 1916</ul> 1917 1918<h3>2.3.6: April 8 2001</h3> 1919<ul> 1920 <li>Code cleanup using extreme gcc compiler warning options, found and 1921 cleared half a dozen potential problem</li> 1922 <li>the Eazel team found an XML parser bug</li> 1923 <li>cleaned up the user of some of the string formatting function. used the 1924 trio library code to provide the one needed when the platform is missing 1925 them</li> 1926 <li>xpath: removed a memory leak and fixed the predicate evaluation 1927 problem, extended the testsuite and cleaned up the result. XPointer seems 1928 broken ...</li> 1929</ul> 1930 1931<h3>2.3.5: Mar 23 2001</h3> 1932<ul> 1933 <li>Biggest change is separate parsing and evaluation of XPath expressions, 1934 there is some new APIs for this too</li> 1935 <li>included a number of bug fixes(XML push parser, 51876, notations, 1936 52299)</li> 1937 <li>Fixed some portability issues</li> 1938</ul> 1939 1940<h3>2.3.4: Mar 10 2001</h3> 1941<ul> 1942 <li>Fixed bugs #51860 and #51861</li> 1943 <li>Added a global variable xmlDefaultBufferSize to allow default buffer 1944 size to be application tunable.</li> 1945 <li>Some cleanup in the validation code, still a bug left and this part 1946 should probably be rewritten to support ambiguous content model :-\</li> 1947 <li>Fix a couple of serious bugs introduced or raised by changes in 2.3.3 1948 parser</li> 1949 <li>Fixed another bug in xmlNodeGetContent()</li> 1950 <li>Bjorn fixed XPath node collection and Number formatting</li> 1951 <li>Fixed a loop reported in the HTML parsing</li> 1952 <li>blank space are reported even if the Dtd content model proves that they 1953 are formatting spaces, this is for XML conformance</li> 1954</ul> 1955 1956<h3>2.3.3: Mar 1 2001</h3> 1957<ul> 1958 <li>small change in XPath for XSLT</li> 1959 <li>documentation cleanups</li> 1960 <li>fix in validation by Gary Pennington</li> 1961 <li>serious parsing performances improvements</li> 1962</ul> 1963 1964<h3>2.3.2: Feb 24 2001</h3> 1965<ul> 1966 <li>chasing XPath bugs, found a bunch, completed some TODO</li> 1967 <li>fixed a Dtd parsing bug</li> 1968 <li>fixed a bug in xmlNodeGetContent</li> 1969 <li>ID/IDREF support partly rewritten by Gary Pennington</li> 1970</ul> 1971 1972<h3>2.3.1: Feb 15 2001</h3> 1973<ul> 1974 <li>some XPath and HTML bug fixes for XSLT</li> 1975 <li>small extension of the hash table interfaces for DOM gdome2 1976 implementation</li> 1977 <li>A few bug fixes</li> 1978</ul> 1979 1980<h3>2.3.0: Feb 8 2001 (2.2.12 was on 25 Jan but I didn't kept track)</h3> 1981<ul> 1982 <li>Lots of XPath bug fixes</li> 1983 <li>Add a mode with Dtd lookup but without validation error reporting for 1984 XSLT</li> 1985 <li>Add support for text node without escaping (XSLT)</li> 1986 <li>bug fixes for xmlCheckFilename</li> 1987 <li>validation code bug fixes from Gary Pennington</li> 1988 <li>Patch from Paul D. Smith correcting URI path normalization</li> 1989 <li>Patch to allow simultaneous install of libxml-devel and 1990 libxml2-devel</li> 1991 <li>the example Makefile is now fixed</li> 1992 <li>added HTML to the RPM packages</li> 1993 <li>tree copying bugfixes</li> 1994 <li>updates to Windows makefiles</li> 1995 <li>optimization patch from Bjorn Reese</li> 1996</ul> 1997 1998<h3>2.2.11: Jan 4 2001</h3> 1999<ul> 2000 <li>bunch of bug fixes (memory I/O, xpath, ftp/http, ...)</li> 2001 <li>added htmlHandleOmittedElem()</li> 2002 <li>Applied Bjorn Reese's IPV6 first patch</li> 2003 <li>Applied Paul D. Smith patches for validation of XInclude results</li> 2004 <li>added XPointer xmlns() new scheme support</li> 2005</ul> 2006 2007<h3>2.2.10: Nov 25 2000</h3> 2008<ul> 2009 <li>Fix the Windows problems of 2.2.8</li> 2010 <li>integrate OpenVMS patches</li> 2011 <li>better handling of some nasty HTML input</li> 2012 <li>Improved the XPointer implementation</li> 2013 <li>integrate a number of provided patches</li> 2014</ul> 2015 2016<h3>2.2.9: Nov 25 2000</h3> 2017<ul> 2018 <li>erroneous release :-(</li> 2019</ul> 2020 2021<h3>2.2.8: Nov 13 2000</h3> 2022<ul> 2023 <li>First version of <a href="http://www.w3.org/TR/xinclude">XInclude</a> 2024 support</li> 2025 <li>Patch in conditional section handling</li> 2026 <li>updated MS compiler project</li> 2027 <li>fixed some XPath problems</li> 2028 <li>added an URI escaping function</li> 2029 <li>some other bug fixes</li> 2030</ul> 2031 2032<h3>2.2.7: Oct 31 2000</h3> 2033<ul> 2034 <li>added message redirection</li> 2035 <li>XPath improvements (thanks TOM !)</li> 2036 <li>xmlIOParseDTD() added</li> 2037 <li>various small fixes in the HTML, URI, HTTP and XPointer support</li> 2038 <li>some cleanup of the Makefile, autoconf and the distribution content</li> 2039</ul> 2040 2041<h3>2.2.6: Oct 25 2000:</h3> 2042<ul> 2043 <li>Added an hash table module, migrated a number of internal structure to 2044 those</li> 2045 <li>Fixed a posteriori validation problems</li> 2046 <li>HTTP module cleanups</li> 2047 <li>HTML parser improvements (tag errors, script/style handling, attribute 2048 normalization)</li> 2049 <li>coalescing of adjacent text nodes</li> 2050 <li>couple of XPath bug fixes, exported the internal API</li> 2051</ul> 2052 2053<h3>2.2.5: Oct 15 2000:</h3> 2054<ul> 2055 <li>XPointer implementation and testsuite</li> 2056 <li>Lot of XPath fixes, added variable and functions registration, more 2057 tests</li> 2058 <li>Portability fixes, lots of enhancements toward an easy Windows build 2059 and release</li> 2060 <li>Late validation fixes</li> 2061 <li>Integrated a lot of contributed patches</li> 2062 <li>added memory management docs</li> 2063 <li>a performance problem when using large buffer seems fixed</li> 2064</ul> 2065 2066<h3>2.2.4: Oct 1 2000:</h3> 2067<ul> 2068 <li>main XPath problem fixed</li> 2069 <li>Integrated portability patches for Windows</li> 2070 <li>Serious bug fixes on the URI and HTML code</li> 2071</ul> 2072 2073<h3>2.2.3: Sep 17 2000</h3> 2074<ul> 2075 <li>bug fixes</li> 2076 <li>cleanup of entity handling code</li> 2077 <li>overall review of all loops in the parsers, all sprintf usage has been 2078 checked too</li> 2079 <li>Far better handling of larges Dtd. Validating against DocBook XML Dtd 2080 works smoothly now.</li> 2081</ul> 2082 2083<h3>1.8.10: Sep 6 2000</h3> 2084<ul> 2085 <li>bug fix release for some Gnome projects</li> 2086</ul> 2087 2088<h3>2.2.2: August 12 2000</h3> 2089<ul> 2090 <li>mostly bug fixes</li> 2091 <li>started adding routines to access xml parser context options</li> 2092</ul> 2093 2094<h3>2.2.1: July 21 2000</h3> 2095<ul> 2096 <li>a purely bug fixes release</li> 2097 <li>fixed an encoding support problem when parsing from a memory block</li> 2098 <li>fixed a DOCTYPE parsing problem</li> 2099 <li>removed a bug in the function allowing to override the memory 2100 allocation routines</li> 2101</ul> 2102 2103<h3>2.2.0: July 14 2000</h3> 2104<ul> 2105 <li>applied a lot of portability fixes</li> 2106 <li>better encoding support/cleanup and saving (content is now always 2107 encoded in UTF-8)</li> 2108 <li>the HTML parser now correctly handles encodings</li> 2109 <li>added xmlHasProp()</li> 2110 <li>fixed a serious problem with &#38;</li> 2111 <li>propagated the fix to FTP client</li> 2112 <li>cleanup, bugfixes, etc ...</li> 2113 <li>Added a page about <a href="encoding.html">libxml Internationalization 2114 support</a></li> 2115</ul> 2116 2117<h3>1.8.9: July 9 2000</h3> 2118<ul> 2119 <li>fixed the spec the RPMs should be better</li> 2120 <li>fixed a serious bug in the FTP implementation, released 1.8.9 to solve 2121 rpmfind users problem</li> 2122</ul> 2123 2124<h3>2.1.1: July 1 2000</h3> 2125<ul> 2126 <li>fixes a couple of bugs in the 2.1.0 packaging</li> 2127 <li>improvements on the HTML parser</li> 2128</ul> 2129 2130<h3>2.1.0 and 1.8.8: June 29 2000</h3> 2131<ul> 2132 <li>1.8.8 is mostly a commodity package for upgrading to libxml2 according 2133 to <a href="upgrade.html">new instructions</a>. It fixes a nasty problem 2134 about &#38; charref parsing</li> 2135 <li>2.1.0 also ease the upgrade from libxml v1 to the recent version. it 2136 also contains numerous fixes and enhancements: 2137 <ul> 2138 <li>added xmlStopParser() to stop parsing</li> 2139 <li>improved a lot parsing speed when there is large CDATA blocs</li> 2140 <li>includes XPath patches provided by Picdar Technology</li> 2141 <li>tried to fix as much as possible DTD validation and namespace 2142 related problems</li> 2143 <li>output to a given encoding has been added/tested</li> 2144 <li>lot of various fixes</li> 2145 </ul> 2146 </li> 2147</ul> 2148 2149<h3>2.0.0: Apr 12 2000</h3> 2150<ul> 2151 <li>First public release of libxml2. If you are using libxml, it's a good 2152 idea to check the 1.x to 2.x upgrade instructions. NOTE: while initially 2153 scheduled for Apr 3 the release occurred only on Apr 12 due to massive 2154 workload.</li> 2155 <li>The include are now located under $prefix/include/libxml (instead of 2156 $prefix/include/gnome-xml), they also are referenced by 2157 <pre>#include <libxml/xxx.h></pre> 2158 <p>instead of</p> 2159 <pre>#include "xxx.h"</pre> 2160 </li> 2161 <li>a new URI module for parsing URIs and following strictly RFC 2396</li> 2162 <li>the memory allocation routines used by libxml can now be overloaded 2163 dynamically by using xmlMemSetup()</li> 2164 <li>The previously CVS only tool tester has been renamed 2165 <strong>xmllint</strong> and is now installed as part of the libxml2 2166 package</li> 2167 <li>The I/O interface has been revamped. There is now ways to plug in 2168 specific I/O modules, either at the URI scheme detection level using 2169 xmlRegisterInputCallbacks() or by passing I/O functions when creating a 2170 parser context using xmlCreateIOParserCtxt()</li> 2171 <li>there is a C preprocessor macro LIBXML_VERSION providing the version 2172 number of the libxml module in use</li> 2173 <li>a number of optional features of libxml can now be excluded at 2174 configure time (FTP/HTTP/HTML/XPath/Debug)</li> 2175</ul> 2176 2177<h3>2.0.0beta: Mar 14 2000</h3> 2178<ul> 2179 <li>This is a first Beta release of libxml version 2</li> 2180 <li>It's available only from<a href="ftp://xmlsoft.org/">xmlsoft.org 2181 FTP</a>, it's packaged as libxml2-2.0.0beta and available as tar and 2182 RPMs</li> 2183 <li>This version is now the head in the Gnome CVS base, the old one is 2184 available under the tag LIB_XML_1_X</li> 2185 <li>This includes a very large set of changes. From a programmatic point 2186 of view applications should not have to be modified too much, check the 2187 <a href="upgrade.html">upgrade page</a></li> 2188 <li>Some interfaces may changes (especially a bit about encoding).</li> 2189 <li>the updates includes: 2190 <ul> 2191 <li>fix I18N support. ISO-Latin-x/UTF-8/UTF-16 (nearly) seems correctly 2192 handled now</li> 2193 <li>Better handling of entities, especially well-formedness checking 2194 and proper PEref extensions in external subsets</li> 2195 <li>DTD conditional sections</li> 2196 <li>Validation now correctly handle entities content</li> 2197 <li><a href="http://rpmfind.net/tools/gdome/messages/0039.html">change 2198 structures to accommodate DOM</a></li> 2199 </ul> 2200 </li> 2201 <li>Serious progress were made toward compliance, <a 2202 href="conf/result.html">here are the result of the test</a> against the 2203 OASIS testsuite (except the Japanese tests since I don't support that 2204 encoding yet). This URL is rebuilt every couple of hours using the CVS 2205 head version.</li> 2206</ul> 2207 2208<h3>1.8.7: Mar 6 2000</h3> 2209<ul> 2210 <li>This is a bug fix release:</li> 2211 <li>It is possible to disable the ignorable blanks heuristic used by 2212 libxml-1.x, a new function xmlKeepBlanksDefault(0) will allow this. Note 2213 that for adherence to XML spec, this behaviour will be disabled by 2214 default in 2.x . The same function will allow to keep compatibility for 2215 old code.</li> 2216 <li>Blanks in <a> </a> constructs are not ignored anymore, 2217 avoiding heuristic is really the Right Way :-\</li> 2218 <li>The unchecked use of snprintf which was breaking libxml-1.8.6 2219 compilation on some platforms has been fixed</li> 2220 <li>nanoftp.c nanohttp.c: Fixed '#' and '?' stripping when processing 2221 URIs</li> 2222</ul> 2223 2224<h3>1.8.6: Jan 31 2000</h3> 2225<ul> 2226 <li>added a nanoFTP transport module, debugged until the new version of <a 2227 href="http://rpmfind.net/linux/rpm2html/rpmfind.html">rpmfind</a> can use 2228 it without troubles</li> 2229</ul> 2230 2231<h3>1.8.5: Jan 21 2000</h3> 2232<ul> 2233 <li>adding APIs to parse a well balanced chunk of XML (production <a 2234 href="http://www.w3.org/TR/REC-xml#NT-content">[43] content</a> of the 2235 XML spec)</li> 2236 <li>fixed a hideous bug in xmlGetProp pointed by Rune.Djurhuus@fast.no</li> 2237 <li>Jody Goldberg <jgoldberg@home.com> provided another patch trying 2238 to solve the zlib checks problems</li> 2239 <li>The current state in gnome CVS base is expected to ship as 1.8.5 with 2240 gnumeric soon</li> 2241</ul> 2242 2243<h3>1.8.4: Jan 13 2000</h3> 2244<ul> 2245 <li>bug fixes, reintroduced xmlNewGlobalNs(), fixed xmlNewNs()</li> 2246 <li>all exit() call should have been removed from libxml</li> 2247 <li>fixed a problem with INCLUDE_WINSOCK on WIN32 platform</li> 2248 <li>added newDocFragment()</li> 2249</ul> 2250 2251<h3>1.8.3: Jan 5 2000</h3> 2252<ul> 2253 <li>a Push interface for the XML and HTML parsers</li> 2254 <li>a shell-like interface to the document tree (try tester --shell :-)</li> 2255 <li>lots of bug fixes and improvement added over XMas holidays</li> 2256 <li>fixed the DTD parsing code to work with the xhtml DTD</li> 2257 <li>added xmlRemoveProp(), xmlRemoveID() and xmlRemoveRef()</li> 2258 <li>Fixed bugs in xmlNewNs()</li> 2259 <li>External entity loading code has been revamped, now it uses 2260 xmlLoadExternalEntity(), some fix on entities processing were added</li> 2261 <li>cleaned up WIN32 includes of socket stuff</li> 2262</ul> 2263 2264<h3>1.8.2: Dec 21 1999</h3> 2265<ul> 2266 <li>I got another problem with includes and C++, I hope this issue is fixed 2267 for good this time</li> 2268 <li>Added a few tree modification functions: xmlReplaceNode, 2269 xmlAddPrevSibling, xmlAddNextSibling, xmlNodeSetName and 2270 xmlDocSetRootElement</li> 2271 <li>Tried to improve the HTML output with help from <a 2272 href="mailto:clahey@umich.edu">Chris Lahey</a></li> 2273</ul> 2274 2275<h3>1.8.1: Dec 18 1999</h3> 2276<ul> 2277 <li>various patches to avoid troubles when using libxml with C++ compilers 2278 the "namespace" keyword and C escaping in include files</li> 2279 <li>a problem in one of the core macros IS_CHAR was corrected</li> 2280 <li>fixed a bug introduced in 1.8.0 breaking default namespace processing, 2281 and more specifically the Dia application</li> 2282 <li>fixed a posteriori validation (validation after parsing, or by using a 2283 Dtd not specified in the original document)</li> 2284 <li>fixed a bug in</li> 2285</ul> 2286 2287<h3>1.8.0: Dec 12 1999</h3> 2288<ul> 2289 <li>cleanup, especially memory wise</li> 2290 <li>the parser should be more reliable, especially the HTML one, it should 2291 not crash, whatever the input !</li> 2292 <li>Integrated various patches, especially a speedup improvement for large 2293 dataset from <a href="mailto:cnygard@bellatlantic.net">Carl Nygard</a>, 2294 configure with --with-buffers to enable them.</li> 2295 <li>attribute normalization, oops should have been added long ago !</li> 2296 <li>attributes defaulted from DTDs should be available, xmlSetProp() now 2297 does entities escaping by default.</li> 2298</ul> 2299 2300<h3>1.7.4: Oct 25 1999</h3> 2301<ul> 2302 <li>Lots of HTML improvement</li> 2303 <li>Fixed some errors when saving both XML and HTML</li> 2304 <li>More examples, the regression tests should now look clean</li> 2305 <li>Fixed a bug with contiguous charref</li> 2306</ul> 2307 2308<h3>1.7.3: Sep 29 1999</h3> 2309<ul> 2310 <li>portability problems fixed</li> 2311 <li>snprintf was used unconditionally, leading to link problems on system 2312 were it's not available, fixed</li> 2313</ul> 2314 2315<h3>1.7.1: Sep 24 1999</h3> 2316<ul> 2317 <li>The basic type for strings manipulated by libxml has been renamed in 2318 1.7.1 from <strong>CHAR</strong> to <strong>xmlChar</strong>. The reason 2319 is that CHAR was conflicting with a predefined type on Windows. However 2320 on non WIN32 environment, compatibility is provided by the way of a 2321 <strong>#define </strong>.</li> 2322 <li>Changed another error : the use of a structure field called errno, and 2323 leading to troubles on platforms where it's a macro</li> 2324</ul> 2325 2326<h3>1.7.0: Sep 23 1999</h3> 2327<ul> 2328 <li>Added the ability to fetch remote DTD or parsed entities, see the <a 2329 href="html/libxml-nanohttp.html">nanohttp</a> module.</li> 2330 <li>Added an errno to report errors by another mean than a simple printf 2331 like callback</li> 2332 <li>Finished ID/IDREF support and checking when validation</li> 2333 <li>Serious memory leaks fixed (there is now a <a 2334 href="html/libxml-xmlmemory.html">memory wrapper</a> module)</li> 2335 <li>Improvement of <a href="http://www.w3.org/TR/xpath">XPath</a> 2336 implementation</li> 2337 <li>Added an HTML parser front-end</li> 2338</ul> 2339 2340<h2><a name="XML">XML</a></h2> 2341 2342<p><a href="http://www.w3.org/TR/REC-xml">XML is a standard</a> for 2343markup-based structured documents. Here is <a name="example">an example XML 2344document</a>:</p> 2345<pre><?xml version="1.0"?> 2346<EXAMPLE prop1="gnome is great" prop2="&amp; linux too"> 2347 <head> 2348 <title>Welcome to Gnome</title> 2349 </head> 2350 <chapter> 2351 <title>The Linux adventure</title> 2352 <p>bla bla bla ...</p> 2353 <image href="linus.gif"/> 2354 <p>...</p> 2355 </chapter> 2356</EXAMPLE></pre> 2357 2358<p>The first line specifies that it is an XML document and gives useful 2359information about its encoding. Then the rest of the document is a text 2360format whose structure is specified by tags between brackets. <strong>Each 2361tag opened has to be closed</strong>. XML is pedantic about this. However, if 2362a tag is empty (no content), a single tag can serve as both the opening and 2363closing tag if it ends with <code>/></code> rather than with 2364<code>></code>. Note that, for example, the image tag has no content (just 2365an attribute) and is closed by ending the tag with <code>/></code>.</p> 2366 2367<p>XML can be applied successfully to a wide range of tasks, ranging from 2368long term structured document maintenance (where it follows the steps of 2369SGML) to simple data encoding mechanisms like configuration file formatting 2370(glade), spreadsheets (gnumeric), or even shorter lived documents such as 2371WebDAV where it is used to encode remote calls between a client and a 2372server.</p> 2373 2374<h2><a name="XSLT">XSLT</a></h2> 2375 2376<p>Check <a href="http://xmlsoft.org/XSLT">the separate libxslt page</a></p> 2377 2378<p><a href="http://www.w3.org/TR/xslt">XSL Transformations</a>, is a 2379language for transforming XML documents into other XML documents (or 2380HTML/textual output).</p> 2381 2382<p>A separate library called libxslt is available implementing XSLT-1.0 for 2383libxml2. This module "libxslt" too can be found in the Gnome CVS base.</p> 2384 2385<p>You can check the progresses on the libxslt <a 2386href="http://xmlsoft.org/XSLT/ChangeLog.html">Changelog</a>.</p> 2387 2388<h2><a name="Python">Python and bindings</a></h2> 2389 2390<p>There are a number of language bindings and wrappers available for 2391libxml2, the list below is not exhaustive. Please contact the <a 2392href="http://mail.gnome.org/mailman/listinfo/xml-bindings">xml-bindings@gnome.org</a> 2393(<a href="http://mail.gnome.org/archives/xml-bindings/">archives</a>) in 2394order to get updates to this list or to discuss the specific topic of libxml2 2395or libxslt wrappers or bindings:</p> 2396<ul> 2397 <li><a href="http://libxmlplusplus.sourceforge.net/">Libxml++</a> seems the 2398 most up-to-date C++ bindings for libxml2, check the <a 2399 href="http://libxmlplusplus.sourceforge.net/reference/html/hierarchy.html">documentation</a> 2400 and the <a 2401 href="http://cvs.sourceforge.net/cgi-bin/viewcvs.cgi/libxmlplusplus/libxml%2b%2b/examples/">examples</a>.</li> 2402 <li>There is another <a href="http://libgdome-cpp.berlios.de/">C++ wrapper 2403 based on the gdome2 bindings</a> maintained by Tobias Peters.</li> 2404 <li>and a third C++ wrapper by Peter Jones <pjones@pmade.org> 2405 <p>Website: <a 2406 href="http://pmade.org/pjones/software/xmlwrapp/">http://pmade.org/pjones/software/xmlwrapp/</a></p> 2407 </li> 2408 <li><a 2409 href="http://mail.gnome.org/archives/xml/2001-March/msg00014.html">Matt 2410 Sergeant</a> developed <a 2411 href="http://axkit.org/download/">XML::LibXSLT</a>, a Perl wrapper for 2412 libxml2/libxslt as part of the <a href="http://axkit.com/">AxKit XML 2413 application server</a>.</li> 2414 <li>If you're interested into scripting XML processing, have a look at <a 2415 href="http://xsh.sourceforge.net/">XSH</a> an XML editing shell based on 2416 Libxml2 Perl bindings.</li> 2417 <li><a href="mailto:dkuhlman@cutter.rexx.com">Dave Kuhlman</a> provides an 2418 earlier version of the libxml/libxslt <a 2419 href="http://www.rexx.com/~dkuhlman">wrappers for Python</a>.</li> 2420 <li>Gopal.V and Peter Minten develop <a 2421 href="http://savannah.gnu.org/projects/libxmlsharp">libxml#</a>, a set of 2422 C# libxml2 bindings.</li> 2423 <li>Petr Kozelka provides <a 2424 href="http://sourceforge.net/projects/libxml2-pas">Pascal units to glue 2425 libxml2</a> with Kylix, Delphi and other Pascal compilers.</li> 2426 <li>Uwe Fechner also provides <a 2427 href="http://sourceforge.net/projects/idom2-pas/">idom2</a>, a DOM2 2428 implementation for Kylix2/D5/D6 from Borland.</li> 2429 <li>There is <a 2430 href="http://rubyforge.org/projects/xml-tools/">bindings for Ruby</a> and 2431 libxml2 bindings are also available in Ruby through the <a 2432 href="http://libgdome-ruby.berlios.de/">libgdome-ruby</a> module 2433 maintained by Tobias Peters.</li> 2434 <li>Steve Ball and contributors maintains <a 2435 href="http://tclxml.sourceforge.net/">libxml2 and libxslt bindings for 2436 Tcl</a>.</li> 2437 <li>libxml2 and libxslt is the default XML library for PHP5.</li> 2438 <li><a href="http://savannah.gnu.org/projects/classpathx/">LibxmlJ</a> is 2439 an effort to create a 100% JAXP-compatible Java wrapper for libxml2 and 2440 libxslt as part of GNU ClasspathX project.</li> 2441 <li>Patrick McPhee provides Rexx bindings fof libxml2 and libxslt, look for 2442 <a href="http://www.interlog.com/~ptjm/software.html">RexxXML</a>.</li> 2443 <li><a href="http://www.satimage.fr/software/en/xml_suite.html">Satimage</a> 2444 provides <a 2445 href="http://www.satimage.fr/software/en/downloads_osaxen.html">XMLLib 2446 osax</a>. This is an osax for Mac OS X with a set of commands to 2447 implement in AppleScript the XML DOM, XPATH and XSLT. Also includes 2448 commands for Property-lists (Apple's fast lookup table XML format.)</li> 2449 <li>Francesco Montorsi developped 2450<a href="https://sourceforge.net/project/showfiles.php?group_id=51305&package_id=45182">wxXml2</a> 2451 wrappers that interface libxml2, allowing wxWidgets applications to 2452 load/save/edit XML instances.</li> 2453</ul> 2454 2455<p>The distribution includes a set of Python bindings, which are guaranteed 2456to be maintained as part of the library in the future, though the Python 2457interface have not yet reached the completeness of the C API.</p> 2458 2459<p>Note that some of the Python purist dislike the default set of Python 2460bindings, rather than complaining I suggest they have a look at 2461<a href="http://codespeak.net/lxml/">lxml the more pythonic bindings for libxml2 and libxslt</a> and 2462<a href="http://codespeak.net/mailman/listinfo/lxml-dev">help Martijn Faassen</a> 2463complete those.</p> 2464 2465<p><a href="mailto:stephane.bidoul@softwareag.com">St�phane Bidoul</a> 2466maintains <a href="http://users.skynet.be/sbi/libxml-python/">a Windows port 2467of the Python bindings</a>.</p> 2468 2469<p>Note to people interested in building bindings, the API is formalized as 2470<a href="libxml2-api.xml">an XML API description file</a> which allows to 2471automate a large part of the Python bindings, this includes function 2472descriptions, enums, structures, typedefs, etc... The Python script used to 2473build the bindings is python/generator.py in the source distribution.</p> 2474 2475<p>To install the Python bindings there are 2 options:</p> 2476<ul> 2477 <li>If you use an RPM based distribution, simply install the <a 2478 href="http://rpmfind.net/linux/rpm2html/search.php?query=libxml2-python">libxml2-python 2479 RPM</a> (and if needed the <a 2480 href="http://rpmfind.net/linux/rpm2html/search.php?query=libxslt-python">libxslt-python 2481 RPM</a>).</li> 2482 <li>Otherwise use the <a href="ftp://xmlsoft.org/python/">libxml2-python 2483 module distribution</a> corresponding to your installed version of 2484 libxml2 and libxslt. Note that to install it you will need both libxml2 2485 and libxslt installed and run "python setup.py build install" in the 2486 module tree.</li> 2487</ul> 2488 2489<p>The distribution includes a set of examples and regression tests for the 2490python bindings in the <code>python/tests</code> directory. Here are some 2491excerpts from those tests:</p> 2492 2493<h3>tst.py:</h3> 2494 2495<p>This is a basic test of the file interface and DOM navigation:</p> 2496<pre>import libxml2, sys 2497 2498doc = libxml2.parseFile("tst.xml") 2499if doc.name != "tst.xml": 2500 print "doc.name failed" 2501 sys.exit(1) 2502root = doc.children 2503if root.name != "doc": 2504 print "root.name failed" 2505 sys.exit(1) 2506child = root.children 2507if child.name != "foo": 2508 print "child.name failed" 2509 sys.exit(1) 2510doc.freeDoc()</pre> 2511 2512<p>The Python module is called libxml2; parseFile is the equivalent of 2513xmlParseFile (most of the bindings are automatically generated, and the xml 2514prefix is removed and the casing convention are kept). All node seen at the 2515binding level share the same subset of accessors:</p> 2516<ul> 2517 <li><code>name</code> : returns the node name</li> 2518 <li><code>type</code> : returns a string indicating the node type</li> 2519 <li><code>content</code> : returns the content of the node, it is based on 2520 xmlNodeGetContent() and hence is recursive.</li> 2521 <li><code>parent</code> , <code>children</code>, <code>last</code>, 2522 <code>next</code>, <code>prev</code>, <code>doc</code>, 2523 <code>properties</code>: pointing to the associated element in the tree, 2524 those may return None in case no such link exists.</li> 2525</ul> 2526 2527<p>Also note the need to explicitly deallocate documents with freeDoc() . 2528Reference counting for libxml2 trees would need quite a lot of work to 2529function properly, and rather than risk memory leaks if not implemented 2530correctly it sounds safer to have an explicit function to free a tree. The 2531wrapper python objects like doc, root or child are them automatically garbage 2532collected.</p> 2533 2534<h3>validate.py:</h3> 2535 2536<p>This test check the validation interfaces and redirection of error 2537messages:</p> 2538<pre>import libxml2 2539 2540#deactivate error messages from the validation 2541def noerr(ctx, str): 2542 pass 2543 2544libxml2.registerErrorHandler(noerr, None) 2545 2546ctxt = libxml2.createFileParserCtxt("invalid.xml") 2547ctxt.validate(1) 2548ctxt.parseDocument() 2549doc = ctxt.doc() 2550valid = ctxt.isValid() 2551doc.freeDoc() 2552if valid != 0: 2553 print "validity check failed"</pre> 2554 2555<p>The first thing to notice is the call to registerErrorHandler(), it 2556defines a new error handler global to the library. It is used to avoid seeing 2557the error messages when trying to validate the invalid document.</p> 2558 2559<p>The main interest of that test is the creation of a parser context with 2560createFileParserCtxt() and how the behaviour can be changed before calling 2561parseDocument() . Similarly the informations resulting from the parsing phase 2562are also available using context methods.</p> 2563 2564<p>Contexts like nodes are defined as class and the libxml2 wrappers maps the 2565C function interfaces in terms of objects method as much as possible. The 2566best to get a complete view of what methods are supported is to look at the 2567libxml2.py module containing all the wrappers.</p> 2568 2569<h3>push.py:</h3> 2570 2571<p>This test show how to activate the push parser interface:</p> 2572<pre>import libxml2 2573 2574ctxt = libxml2.createPushParser(None, "<foo", 4, "test.xml") 2575ctxt.parseChunk("/>", 2, 1) 2576doc = ctxt.doc() 2577 2578doc.freeDoc()</pre> 2579 2580<p>The context is created with a special call based on the 2581xmlCreatePushParser() from the C library. The first argument is an optional 2582SAX callback object, then the initial set of data, the length and the name of 2583the resource in case URI-References need to be computed by the parser.</p> 2584 2585<p>Then the data are pushed using the parseChunk() method, the last call 2586setting the third argument terminate to 1.</p> 2587 2588<h3>pushSAX.py:</h3> 2589 2590<p>this test show the use of the event based parsing interfaces. In this case 2591the parser does not build a document, but provides callback information as 2592the parser makes progresses analyzing the data being provided:</p> 2593<pre>import libxml2 2594log = "" 2595 2596class callback: 2597 def startDocument(self): 2598 global log 2599 log = log + "startDocument:" 2600 2601 def endDocument(self): 2602 global log 2603 log = log + "endDocument:" 2604 2605 def startElement(self, tag, attrs): 2606 global log 2607 log = log + "startElement %s %s:" % (tag, attrs) 2608 2609 def endElement(self, tag): 2610 global log 2611 log = log + "endElement %s:" % (tag) 2612 2613 def characters(self, data): 2614 global log 2615 log = log + "characters: %s:" % (data) 2616 2617 def warning(self, msg): 2618 global log 2619 log = log + "warning: %s:" % (msg) 2620 2621 def error(self, msg): 2622 global log 2623 log = log + "error: %s:" % (msg) 2624 2625 def fatalError(self, msg): 2626 global log 2627 log = log + "fatalError: %s:" % (msg) 2628 2629handler = callback() 2630 2631ctxt = libxml2.createPushParser(handler, "<foo", 4, "test.xml") 2632chunk = " url='tst'>b" 2633ctxt.parseChunk(chunk, len(chunk), 0) 2634chunk = "ar</foo>" 2635ctxt.parseChunk(chunk, len(chunk), 1) 2636 2637reference = "startDocument:startElement foo {'url': 'tst'}:" + \ 2638 "characters: bar:endElement foo:endDocument:" 2639if log != reference: 2640 print "Error got: %s" % log 2641 print "Expected: %s" % reference</pre> 2642 2643<p>The key object in that test is the handler, it provides a number of entry 2644points which can be called by the parser as it makes progresses to indicate 2645the information set obtained. The full set of callback is larger than what 2646the callback class in that specific example implements (see the SAX 2647definition for a complete list). The wrapper will only call those supplied by 2648the object when activated. The startElement receives the names of the element 2649and a dictionary containing the attributes carried by this element.</p> 2650 2651<p>Also note that the reference string generated from the callback shows a 2652single character call even though the string "bar" is passed to the parser 2653from 2 different call to parseChunk()</p> 2654 2655<h3>xpath.py:</h3> 2656 2657<p>This is a basic test of XPath wrappers support</p> 2658<pre>import libxml2 2659 2660doc = libxml2.parseFile("tst.xml") 2661ctxt = doc.xpathNewContext() 2662res = ctxt.xpathEval("//*") 2663if len(res) != 2: 2664 print "xpath query: wrong node set size" 2665 sys.exit(1) 2666if res[0].name != "doc" or res[1].name != "foo": 2667 print "xpath query: wrong node set value" 2668 sys.exit(1) 2669doc.freeDoc() 2670ctxt.xpathFreeContext()</pre> 2671 2672<p>This test parses a file, then create an XPath context to evaluate XPath 2673expression on it. The xpathEval() method execute an XPath query and returns 2674the result mapped in a Python way. String and numbers are natively converted, 2675and node sets are returned as a tuple of libxml2 Python nodes wrappers. Like 2676the document, the XPath context need to be freed explicitly, also not that 2677the result of the XPath query may point back to the document tree and hence 2678the document must be freed after the result of the query is used.</p> 2679 2680<h3>xpathext.py:</h3> 2681 2682<p>This test shows how to extend the XPath engine with functions written in 2683python:</p> 2684<pre>import libxml2 2685 2686def foo(ctx, x): 2687 return x + 1 2688 2689doc = libxml2.parseFile("tst.xml") 2690ctxt = doc.xpathNewContext() 2691libxml2.registerXPathFunction(ctxt._o, "foo", None, foo) 2692res = ctxt.xpathEval("foo(1)") 2693if res != 2: 2694 print "xpath extension failure" 2695doc.freeDoc() 2696ctxt.xpathFreeContext()</pre> 2697 2698<p>Note how the extension function is registered with the context (but that 2699part is not yet finalized, this may change slightly in the future).</p> 2700 2701<h3>tstxpath.py:</h3> 2702 2703<p>This test is similar to the previous one but shows how the extension 2704function can access the XPath evaluation context:</p> 2705<pre>def foo(ctx, x): 2706 global called 2707 2708 # 2709 # test that access to the XPath evaluation contexts 2710 # 2711 pctxt = libxml2.xpathParserContext(_obj=ctx) 2712 ctxt = pctxt.context() 2713 called = ctxt.function() 2714 return x + 1</pre> 2715 2716<p>All the interfaces around the XPath parser(or rather evaluation) context 2717are not finalized, but it should be sufficient to do contextual work at the 2718evaluation point.</p> 2719 2720<h3>Memory debugging:</h3> 2721 2722<p>last but not least, all tests starts with the following prologue:</p> 2723<pre>#memory debug specific 2724libxml2.debugMemory(1)</pre> 2725 2726<p>and ends with the following epilogue:</p> 2727<pre>#memory debug specific 2728libxml2.cleanupParser() 2729if libxml2.debugMemory(1) == 0: 2730 print "OK" 2731else: 2732 print "Memory leak %d bytes" % (libxml2.debugMemory(1)) 2733 libxml2.dumpMemory()</pre> 2734 2735<p>Those activate the memory debugging interface of libxml2 where all 2736allocated block in the library are tracked. The prologue then cleans up the 2737library state and checks that all allocated memory has been freed. If not it 2738calls dumpMemory() which saves that list in a <code>.memdump</code> file.</p> 2739 2740<h2><a name="architecture">libxml2 architecture</a></h2> 2741 2742<p>Libxml2 is made of multiple components; some of them are optional, and 2743most of the block interfaces are public. The main components are:</p> 2744<ul> 2745 <li>an Input/Output layer</li> 2746 <li>FTP and HTTP client layers (optional)</li> 2747 <li>an Internationalization layer managing the encodings support</li> 2748 <li>a URI module</li> 2749 <li>the XML parser and its basic SAX interface</li> 2750 <li>an HTML parser using the same SAX interface (optional)</li> 2751 <li>a SAX tree module to build an in-memory DOM representation</li> 2752 <li>a tree module to manipulate the DOM representation</li> 2753 <li>a validation module using the DOM representation (optional)</li> 2754 <li>an XPath module for global lookup in a DOM representation 2755 (optional)</li> 2756 <li>a debug module (optional)</li> 2757</ul> 2758 2759<p>Graphically this gives the following:</p> 2760 2761<p><img src="libxml.gif" alt="a graphical view of the various"></p> 2762 2763<p></p> 2764 2765<h2><a name="tree">The tree output</a></h2> 2766 2767<p>The parser returns a tree built during the document analysis. The value 2768returned is an <strong>xmlDocPtr</strong> (i.e., a pointer to an 2769<strong>xmlDoc</strong> structure). This structure contains information such 2770as the file name, the document type, and a <strong>children</strong> pointer 2771which is the root of the document (or more exactly the first child under the 2772root which is the document). The tree is made of <strong>xmlNode</strong>s, 2773chained in double-linked lists of siblings and with a children<->parent 2774relationship. An xmlNode can also carry properties (a chain of xmlAttr 2775structures). An attribute may have a value which is a list of TEXT or 2776ENTITY_REF nodes.</p> 2777 2778<p>Here is an example (erroneous with respect to the XML spec since there 2779should be only one ELEMENT under the root):</p> 2780 2781<p><img src="structure.gif" alt=" structure.gif "></p> 2782 2783<p>In the source package there is a small program (not installed by default) 2784called <strong>xmllint</strong> which parses XML files given as argument and 2785prints them back as parsed. This is useful for detecting errors both in XML 2786code and in the XML parser itself. It has an option <strong>--debug</strong> 2787which prints the actual in-memory structure of the document; here is the 2788result with the <a href="#example">example</a> given before:</p> 2789<pre>DOCUMENT 2790version=1.0 2791standalone=true 2792 ELEMENT EXAMPLE 2793 ATTRIBUTE prop1 2794 TEXT 2795 content=gnome is great 2796 ATTRIBUTE prop2 2797 ENTITY_REF 2798 TEXT 2799 content= linux too 2800 ELEMENT head 2801 ELEMENT title 2802 TEXT 2803 content=Welcome to Gnome 2804 ELEMENT chapter 2805 ELEMENT title 2806 TEXT 2807 content=The Linux adventure 2808 ELEMENT p 2809 TEXT 2810 content=bla bla bla ... 2811 ELEMENT image 2812 ATTRIBUTE href 2813 TEXT 2814 content=linus.gif 2815 ELEMENT p 2816 TEXT 2817 content=...</pre> 2818 2819<p>This should be useful for learning the internal representation model.</p> 2820 2821<h2><a name="interface">The SAX interface</a></h2> 2822 2823<p>Sometimes the DOM tree output is just too large to fit reasonably into 2824memory. In that case (and if you don't expect to save back the XML document 2825loaded using libxml), it's better to use the SAX interface of libxml. SAX is 2826a <strong>callback-based interface</strong> to the parser. Before parsing, 2827the application layer registers a customized set of callbacks which are 2828called by the library as it progresses through the XML input.</p> 2829 2830<p>To get more detailed step-by-step guidance on using the SAX interface of 2831libxml, see the <a 2832href="http://www.daa.com.au/~james/gnome/xml-sax/xml-sax.html">nice 2833documentation</a>.written by <a href="mailto:james@daa.com.au">James 2834Henstridge</a>.</p> 2835 2836<p>You can debug the SAX behaviour by using the <strong>testSAX</strong> 2837program located in the gnome-xml module (it's usually not shipped in the 2838binary packages of libxml, but you can find it in the tar source 2839distribution). Here is the sequence of callbacks that would be reported by 2840testSAX when parsing the example XML document shown earlier:</p> 2841<pre>SAX.setDocumentLocator() 2842SAX.startDocument() 2843SAX.getEntity(amp) 2844SAX.startElement(EXAMPLE, prop1='gnome is great', prop2='&amp; linux too') 2845SAX.characters( , 3) 2846SAX.startElement(head) 2847SAX.characters( , 4) 2848SAX.startElement(title) 2849SAX.characters(Welcome to Gnome, 16) 2850SAX.endElement(title) 2851SAX.characters( , 3) 2852SAX.endElement(head) 2853SAX.characters( , 3) 2854SAX.startElement(chapter) 2855SAX.characters( , 4) 2856SAX.startElement(title) 2857SAX.characters(The Linux adventure, 19) 2858SAX.endElement(title) 2859SAX.characters( , 4) 2860SAX.startElement(p) 2861SAX.characters(bla bla bla ..., 15) 2862SAX.endElement(p) 2863SAX.characters( , 4) 2864SAX.startElement(image, href='linus.gif') 2865SAX.endElement(image) 2866SAX.characters( , 4) 2867SAX.startElement(p) 2868SAX.characters(..., 3) 2869SAX.endElement(p) 2870SAX.characters( , 3) 2871SAX.endElement(chapter) 2872SAX.characters( , 1) 2873SAX.endElement(EXAMPLE) 2874SAX.endDocument()</pre> 2875 2876<p>Most of the other interfaces of libxml2 are based on the DOM tree-building 2877facility, so nearly everything up to the end of this document presupposes the 2878use of the standard DOM tree build. Note that the DOM tree itself is built by 2879a set of registered default callbacks, without internal specific 2880interface.</p> 2881 2882<h2><a name="Validation">Validation & DTDs</a></h2> 2883 2884<p>Table of Content:</p> 2885<ol> 2886 <li><a href="#General5">General overview</a></li> 2887 <li><a href="#definition">The definition</a></li> 2888 <li><a href="#Simple">Simple rules</a> 2889 <ol> 2890 <li><a href="#reference">How to reference a DTD from a document</a></li> 2891 <li><a href="#Declaring">Declaring elements</a></li> 2892 <li><a href="#Declaring1">Declaring attributes</a></li> 2893 </ol> 2894 </li> 2895 <li><a href="#Some">Some examples</a></li> 2896 <li><a href="#validate">How to validate</a></li> 2897 <li><a href="#Other">Other resources</a></li> 2898</ol> 2899 2900<h3><a name="General5">General overview</a></h3> 2901 2902<p>Well what is validation and what is a DTD ?</p> 2903 2904<p>DTD is the acronym for Document Type Definition. This is a description of 2905the content for a family of XML files. This is part of the XML 1.0 2906specification, and allows one to describe and verify that a given document 2907instance conforms to the set of rules detailing its structure and content.</p> 2908 2909<p>Validation is the process of checking a document against a DTD (more 2910generally against a set of construction rules).</p> 2911 2912<p>The validation process and building DTDs are the two most difficult parts 2913of the XML life cycle. Briefly a DTD defines all the possible elements to be 2914found within your document, what is the formal shape of your document tree 2915(by defining the allowed content of an element; either text, a regular 2916expression for the allowed list of children, or mixed content i.e. both text 2917and children). The DTD also defines the valid attributes for all elements and 2918the types of those attributes.</p> 2919 2920<h3><a name="definition1">The definition</a></h3> 2921 2922<p>The <a href="http://www.w3.org/TR/REC-xml">W3C XML Recommendation</a> (<a 2923href="http://www.xml.com/axml/axml.html">Tim Bray's annotated version of 2924Rev1</a>):</p> 2925<ul> 2926 <li><a href="http://www.w3.org/TR/REC-xml#elemdecls">Declaring 2927 elements</a></li> 2928 <li><a href="http://www.w3.org/TR/REC-xml#attdecls">Declaring 2929 attributes</a></li> 2930</ul> 2931 2932<p>(unfortunately) all this is inherited from the SGML world, the syntax is 2933ancient...</p> 2934 2935<h3><a name="Simple1">Simple rules</a></h3> 2936 2937<p>Writing DTDs can be done in many ways. The rules to build them if you need 2938something permanent or something which can evolve over time can be radically 2939different. Really complex DTDs like DocBook ones are flexible but quite 2940harder to design. I will just focus on DTDs for a formats with a fixed simple 2941structure. It is just a set of basic rules, and definitely not exhaustive nor 2942usable for complex DTD design.</p> 2943 2944<h4><a name="reference1">How to reference a DTD from a document</a>:</h4> 2945 2946<p>Assuming the top element of the document is <code>spec</code> and the dtd 2947is placed in the file <code>mydtd</code> in the subdirectory 2948<code>dtds</code> of the directory from where the document were loaded:</p> 2949 2950<p><code><!DOCTYPE spec SYSTEM "dtds/mydtd"></code></p> 2951 2952<p>Notes:</p> 2953<ul> 2954 <li>The system string is actually an URI-Reference (as defined in <a 2955 href="http://www.ietf.org/rfc/rfc2396.txt">RFC 2396</a>) so you can use a 2956 full URL string indicating the location of your DTD on the Web. This is a 2957 really good thing to do if you want others to validate your document.</li> 2958 <li>It is also possible to associate a <code>PUBLIC</code> identifier (a 2959 magic string) so that the DTD is looked up in catalogs on the client side 2960 without having to locate it on the web.</li> 2961 <li>A DTD contains a set of element and attribute declarations, but they 2962 don't define what the root of the document should be. This is explicitly 2963 told to the parser/validator as the first element of the 2964 <code>DOCTYPE</code> declaration.</li> 2965</ul> 2966 2967<h4><a name="Declaring2">Declaring elements</a>:</h4> 2968 2969<p>The following declares an element <code>spec</code>:</p> 2970 2971<p><code><!ELEMENT spec (front, body, back?)></code></p> 2972 2973<p>It also expresses that the spec element contains one <code>front</code>, 2974one <code>body</code> and one optional <code>back</code> children elements in 2975this order. The declaration of one element of the structure and its content 2976are done in a single declaration. Similarly the following declares 2977<code>div1</code> elements:</p> 2978 2979<p><code><!ELEMENT div1 (head, (p | list | note)*, div2?)></code></p> 2980 2981<p>which means div1 contains one <code>head</code> then a series of optional 2982<code>p</code>, <code>list</code>s and <code>note</code>s and then an 2983optional <code>div2</code>. And last but not least an element can contain 2984text:</p> 2985 2986<p><code><!ELEMENT b (#PCDATA)></code></p> 2987 2988<p><code>b</code> contains text or being of mixed content (text and elements 2989in no particular order):</p> 2990 2991<p><code><!ELEMENT p (#PCDATA|a|ul|b|i|em)*></code></p> 2992 2993<p><code>p </code>can contain text or <code>a</code>, <code>ul</code>, 2994<code>b</code>, <code>i </code>or <code>em</code> elements in no particular 2995order.</p> 2996 2997<h4><a name="Declaring1">Declaring attributes</a>:</h4> 2998 2999<p>Again the attributes declaration includes their content definition:</p> 3000 3001<p><code><!ATTLIST termdef name CDATA #IMPLIED></code></p> 3002 3003<p>means that the element <code>termdef</code> can have a <code>name</code> 3004attribute containing text (<code>CDATA</code>) and which is optional 3005(<code>#IMPLIED</code>). The attribute value can also be defined within a 3006set:</p> 3007 3008<p><code><!ATTLIST list type (bullets|ordered|glossary) 3009"ordered"></code></p> 3010 3011<p>means <code>list</code> element have a <code>type</code> attribute with 3 3012allowed values "bullets", "ordered" or "glossary" and which default to 3013"ordered" if the attribute is not explicitly specified.</p> 3014 3015<p>The content type of an attribute can be text (<code>CDATA</code>), 3016anchor/reference/references 3017(<code>ID</code>/<code>IDREF</code>/<code>IDREFS</code>), entity(ies) 3018(<code>ENTITY</code>/<code>ENTITIES</code>) or name(s) 3019(<code>NMTOKEN</code>/<code>NMTOKENS</code>). The following defines that a 3020<code>chapter</code> element can have an optional <code>id</code> attribute 3021of type <code>ID</code>, usable for reference from attribute of type 3022IDREF:</p> 3023 3024<p><code><!ATTLIST chapter id ID #IMPLIED></code></p> 3025 3026<p>The last value of an attribute definition can be <code>#REQUIRED 3027</code>meaning that the attribute has to be given, <code>#IMPLIED</code> 3028meaning that it is optional, or the default value (possibly prefixed by 3029<code>#FIXED</code> if it is the only allowed).</p> 3030 3031<p>Notes:</p> 3032<ul> 3033 <li>Usually the attributes pertaining to a given element are declared in a 3034 single expression, but it is just a convention adopted by a lot of DTD 3035 writers: 3036 <pre><!ATTLIST termdef 3037 id ID #REQUIRED 3038 name CDATA #IMPLIED></pre> 3039 <p>The previous construct defines both <code>id</code> and 3040 <code>name</code> attributes for the element <code>termdef</code>.</p> 3041 </li> 3042</ul> 3043 3044<h3><a name="Some1">Some examples</a></h3> 3045 3046<p>The directory <code>test/valid/dtds/</code> in the libxml2 distribution 3047contains some complex DTD examples. The example in the file 3048<code>test/valid/dia.xml</code> shows an XML file where the simple DTD is 3049directly included within the document.</p> 3050 3051<h3><a name="validate1">How to validate</a></h3> 3052 3053<p>The simplest way is to use the xmllint program included with libxml. The 3054<code>--valid</code> option turns-on validation of the files given as input. 3055For example the following validates a copy of the first revision of the XML 30561.0 specification:</p> 3057 3058<p><code>xmllint --valid --noout test/valid/REC-xml-19980210.xml</code></p> 3059 3060<p>the -- noout is used to disable output of the resulting tree.</p> 3061 3062<p>The <code>--dtdvalid dtd</code> allows validation of the document(s) 3063against a given DTD.</p> 3064 3065<p>Libxml2 exports an API to handle DTDs and validation, check the <a 3066href="http://xmlsoft.org/html/libxml-valid.html">associated 3067description</a>.</p> 3068 3069<h3><a name="Other1">Other resources</a></h3> 3070 3071<p>DTDs are as old as SGML. So there may be a number of examples on-line, I 3072will just list one for now, others pointers welcome:</p> 3073<ul> 3074 <li><a href="http://www.xml101.com:8081/dtd/">XML-101 DTD</a></li> 3075</ul> 3076 3077<p>I suggest looking at the examples found under test/valid/dtd and any of 3078the large number of books available on XML. The dia example in test/valid 3079should be both simple and complete enough to allow you to build your own.</p> 3080 3081<p></p> 3082 3083<h2><a name="Memory">Memory Management</a></h2> 3084 3085<p>Table of Content:</p> 3086<ol> 3087 <li><a href="#General3">General overview</a></li> 3088 <li><a href="#setting">Setting libxml2 set of memory routines</a></li> 3089 <li><a href="#cleanup">Cleaning up after parsing</a></li> 3090 <li><a href="#Debugging">Debugging routines</a></li> 3091 <li><a href="#General4">General memory requirements</a></li> 3092</ol> 3093 3094<h3><a name="General3">General overview</a></h3> 3095 3096<p>The module <code><a 3097href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlmemory.h</a></code> 3098provides the interfaces to the libxml2 memory system:</p> 3099<ul> 3100 <li>libxml2 does not use the libc memory allocator directly but xmlFree(), 3101 xmlMalloc() and xmlRealloc()</li> 3102 <li>those routines can be reallocated to a specific set of routine, by 3103 default the libc ones i.e. free(), malloc() and realloc()</li> 3104 <li>the xmlmemory.c module includes a set of debugging routine</li> 3105</ul> 3106 3107<h3><a name="setting">Setting libxml2 set of memory routines</a></h3> 3108 3109<p>It is sometimes useful to not use the default memory allocator, either for 3110debugging, analysis or to implement a specific behaviour on memory management 3111(like on embedded systems). Two function calls are available to do so:</p> 3112<ul> 3113 <li><a href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlMemGet 3114 ()</a> which return the current set of functions in use by the parser</li> 3115 <li><a 3116 href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlMemSetup()</a> 3117 which allow to set up a new set of memory allocation functions</li> 3118</ul> 3119 3120<p>Of course a call to xmlMemSetup() should probably be done before calling 3121any other libxml2 routines (unless you are sure your allocations routines are 3122compatibles).</p> 3123 3124<h3><a name="cleanup">Cleaning up after parsing</a></h3> 3125 3126<p>Libxml2 is not stateless, there is a few set of memory structures needing 3127allocation before the parser is fully functional (some encoding structures 3128for example). This also mean that once parsing is finished there is a tiny 3129amount of memory (a few hundred bytes) which can be recollected if you don't 3130reuse the parser immediately:</p> 3131<ul> 3132 <li><a href="http://xmlsoft.org/html/libxml-parser.html">xmlCleanupParser 3133 ()</a> is a centralized routine to free the parsing states. Note that it 3134 won't deallocate any produced tree if any (use the xmlFreeDoc() and 3135 related routines for this).</li> 3136 <li><a href="http://xmlsoft.org/html/libxml-parser.html">xmlInitParser 3137 ()</a> is the dual routine allowing to preallocate the parsing state 3138 which can be useful for example to avoid initialization reentrancy 3139 problems when using libxml2 in multithreaded applications</li> 3140</ul> 3141 3142<p>Generally xmlCleanupParser() is safe, if needed the state will be rebuild 3143at the next invocation of parser routines, but be careful of the consequences 3144in multithreaded applications.</p> 3145 3146<h3><a name="Debugging">Debugging routines</a></h3> 3147 3148<p>When configured using --with-mem-debug flag (off by default), libxml2 uses 3149a set of memory allocation debugging routines keeping track of all allocated 3150blocks and the location in the code where the routine was called. A couple of 3151other debugging routines allow to dump the memory allocated infos to a file 3152or call a specific routine when a given block number is allocated:</p> 3153<ul> 3154 <li><a 3155 href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlMallocLoc()</a> 3156 <a 3157 href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlReallocLoc()</a> 3158 and <a 3159 href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlMemStrdupLoc()</a> 3160 are the memory debugging replacement allocation routines</li> 3161 <li><a href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlMemoryDump 3162 ()</a> dumps all the informations about the allocated memory block lefts 3163 in the <code>.memdump</code> file</li> 3164</ul> 3165 3166<p>When developing libxml2 memory debug is enabled, the tests programs call 3167xmlMemoryDump () and the "make test" regression tests will check for any 3168memory leak during the full regression test sequence, this helps a lot 3169ensuring that libxml2 does not leak memory and bullet proof memory 3170allocations use (some libc implementations are known to be far too permissive 3171resulting in major portability problems!).</p> 3172 3173<p>If the .memdump reports a leak, it displays the allocation function and 3174also tries to give some informations about the content and structure of the 3175allocated blocks left. This is sufficient in most cases to find the culprit, 3176but not always. Assuming the allocation problem is reproducible, it is 3177possible to find more easily:</p> 3178<ol> 3179 <li>write down the block number xxxx not allocated</li> 3180 <li>export the environment variable XML_MEM_BREAKPOINT=xxxx , the easiest 3181 when using GDB is to simply give the command 3182 <p><code>set environment XML_MEM_BREAKPOINT xxxx</code></p> 3183 <p>before running the program.</p> 3184 </li> 3185 <li>run the program under a debugger and set a breakpoint on 3186 xmlMallocBreakpoint() a specific function called when this precise block 3187 is allocated</li> 3188 <li>when the breakpoint is reached you can then do a fine analysis of the 3189 allocation an step to see the condition resulting in the missing 3190 deallocation.</li> 3191</ol> 3192 3193<p>I used to use a commercial tool to debug libxml2 memory problems but after 3194noticing that it was not detecting memory leaks that simple mechanism was 3195used and proved extremely efficient until now. Lately I have also used <a 3196href="http://developer.kde.org/~sewardj/">valgrind</a> with quite some 3197success, it is tied to the i386 architecture since it works by emulating the 3198processor and instruction set, it is slow but extremely efficient, i.e. it 3199spot memory usage errors in a very precise way.</p> 3200 3201<h3><a name="General4">General memory requirements</a></h3> 3202 3203<p>How much libxml2 memory require ? It's hard to tell in average it depends 3204of a number of things:</p> 3205<ul> 3206 <li>the parser itself should work in a fixed amount of memory, except for 3207 information maintained about the stacks of names and entities locations. 3208 The I/O and encoding handlers will probably account for a few KBytes. 3209 This is true for both the XML and HTML parser (though the HTML parser 3210 need more state).</li> 3211 <li>If you are generating the DOM tree then memory requirements will grow 3212 nearly linear with the size of the data. In general for a balanced 3213 textual document the internal memory requirement is about 4 times the 3214 size of the UTF8 serialization of this document (example the XML-1.0 3215 recommendation is a bit more of 150KBytes and takes 650KBytes of main 3216 memory when parsed). Validation will add a amount of memory required for 3217 maintaining the external Dtd state which should be linear with the 3218 complexity of the content model defined by the Dtd</li> 3219 <li>If you need to work with fixed memory requirements or don't need the 3220 full DOM tree then using the <a href="xmlreader.html">xmlReader 3221 interface</a> is probably the best way to proceed, it still allows to 3222 validate or operate on subset of the tree if needed.</li> 3223 <li>If you don't care about the advanced features of libxml2 like 3224 validation, DOM, XPath or XPointer, don't use entities, need to work with 3225 fixed memory requirements, and try to get the fastest parsing possible 3226 then the SAX interface should be used, but it has known restrictions.</li> 3227</ul> 3228 3229<p></p> 3230 3231<h2><a name="Encodings">Encodings support</a></h2> 3232 3233<p>If you are not really familiar with Internationalization (usual shortcut 3234is I18N) , Unicode, characters and glyphs, I suggest you read a <a 3235href="http://www.tbray.org/ongoing/When/200x/2003/04/06/Unicode">presentation</a> 3236by Tim Bray on Unicode and why you should care about it.</p> 3237<p>If you don't understand why <b>it does not make sense to have a string 3238without knowing what encoding it uses</b>, then as Joel Spolsky said 3239<a href="http://www.joelonsoftware.com/articles/Unicode.html">please do 3240not write another line of code until you finish reading that article.</a>. 3241It is a prerequisite to understand this page, and avoid a lot of problems 3242with libxml2, XML or text processing in general.</p> 3243 3244<p>Table of Content:</p> 3245<ol> 3246 <li><a href="encoding.html#What">What does internationalization support 3247 mean ?</a></li> 3248 <li><a href="encoding.html#internal">The internal encoding, how and 3249 why</a></li> 3250 <li><a href="encoding.html#implemente">How is it implemented ?</a></li> 3251 <li><a href="encoding.html#Default">Default supported encodings</a></li> 3252 <li><a href="encoding.html#extend">How to extend the existing 3253 support</a></li> 3254</ol> 3255 3256<h3><a name="What">What does internationalization support mean ?</a></h3> 3257 3258<p>XML was designed from the start to allow the support of any character set 3259by using Unicode. Any conformant XML parser has to support the UTF-8 and 3260UTF-16 default encodings which can both express the full unicode ranges. UTF8 3261is a variable length encoding whose greatest points are to reuse the same 3262encoding for ASCII and to save space for Western encodings, but it is a bit 3263more complex to handle in practice. UTF-16 use 2 bytes per character (and 3264sometimes combines two pairs), it makes implementation easier, but looks a 3265bit overkill for Western languages encoding. Moreover the XML specification 3266allows the document to be encoded in other encodings at the condition that 3267they are clearly labeled as such. For example the following is a wellformed 3268XML document encoded in ISO-8859-1 and using accentuated letters that we 3269French like for both markup and content:</p> 3270<pre><?xml version="1.0" encoding="ISO-8859-1"?> 3271<tr�s>l�</tr�s></pre> 3272 3273<p>Having internationalization support in libxml2 means the following:</p> 3274<ul> 3275 <li>the document is properly parsed</li> 3276 <li>informations about it's encoding are saved</li> 3277 <li>it can be modified</li> 3278 <li>it can be saved in its original encoding</li> 3279 <li>it can also be saved in another encoding supported by libxml2 (for 3280 example straight UTF8 or even an ASCII form)</li> 3281</ul> 3282 3283<p>Another very important point is that the whole libxml2 API, with the 3284exception of a few routines to read with a specific encoding or save to a 3285specific encoding, is completely agnostic about the original encoding of the 3286document.</p> 3287 3288<p>It should be noted too that the HTML parser embedded in libxml2 now obey 3289the same rules too, the following document will be (as of 2.2.2) handled in 3290an internationalized fashion by libxml2 too:</p> 3291<pre><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" 3292 "http://www.w3.org/TR/REC-html40/loose.dtd"> 3293<html lang="fr"> 3294<head> 3295 <META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=ISO-8859-1"> 3296</head> 3297<body> 3298<p>W3C cr�e des standards pour le Web.</body> 3299</html></pre> 3300 3301<h3><a name="internal">The internal encoding, how and why</a></h3> 3302 3303<p>One of the core decisions was to force all documents to be converted to a 3304default internal encoding, and that encoding to be UTF-8, here are the 3305rationales for those choices:</p> 3306<ul> 3307 <li>keeping the native encoding in the internal form would force the libxml 3308 users (or the code associated) to be fully aware of the encoding of the 3309 original document, for examples when adding a text node to a document, 3310 the content would have to be provided in the document encoding, i.e. the 3311 client code would have to check it before hand, make sure it's conformant 3312 to the encoding, etc ... Very hard in practice, though in some specific 3313 cases this may make sense.</li> 3314 <li>the second decision was which encoding. From the XML spec only UTF8 and 3315 UTF16 really makes sense as being the two only encodings for which there 3316 is mandatory support. UCS-4 (32 bits fixed size encoding) could be 3317 considered an intelligent choice too since it's a direct Unicode mapping 3318 support. I selected UTF-8 on the basis of efficiency and compatibility 3319 with surrounding software: 3320 <ul> 3321 <li>UTF-8 while a bit more complex to convert from/to (i.e. slightly 3322 more costly to import and export CPU wise) is also far more compact 3323 than UTF-16 (and UCS-4) for a majority of the documents I see it used 3324 for right now (RPM RDF catalogs, advogato data, various configuration 3325 file formats, etc.) and the key point for today's computer 3326 architecture is efficient uses of caches. If one nearly double the 3327 memory requirement to store the same amount of data, this will trash 3328 caches (main memory/external caches/internal caches) and my take is 3329 that this harms the system far more than the CPU requirements needed 3330 for the conversion to UTF-8</li> 3331 <li>Most of libxml2 version 1 users were using it with straight ASCII 3332 most of the time, doing the conversion with an internal encoding 3333 requiring all their code to be rewritten was a serious show-stopper 3334 for using UTF-16 or UCS-4.</li> 3335 <li>UTF-8 is being used as the de-facto internal encoding standard for 3336 related code like the <a href="http://www.pango.org/">pango</a> 3337 upcoming Gnome text widget, and a lot of Unix code (yet another place 3338 where Unix programmer base takes a different approach from Microsoft 3339 - they are using UTF-16)</li> 3340 </ul> 3341 </li> 3342</ul> 3343 3344<p>What does this mean in practice for the libxml2 user:</p> 3345<ul> 3346 <li>xmlChar, the libxml2 data type is a byte, those bytes must be assembled 3347 as UTF-8 valid strings. The proper way to terminate an xmlChar * string 3348 is simply to append 0 byte, as usual.</li> 3349 <li>One just need to make sure that when using chars outside the ASCII set, 3350 the values has been properly converted to UTF-8</li> 3351</ul> 3352 3353<h3><a name="implemente">How is it implemented ?</a></h3> 3354 3355<p>Let's describe how all this works within libxml, basically the I18N 3356(internationalization) support get triggered only during I/O operation, i.e. 3357when reading a document or saving one. Let's look first at the reading 3358sequence:</p> 3359<ol> 3360 <li>when a document is processed, we usually don't know the encoding, a 3361 simple heuristic allows to detect UTF-16 and UCS-4 from encodings where 3362 the ASCII range (0-0x7F) maps with ASCII</li> 3363 <li>the xml declaration if available is parsed, including the encoding 3364 declaration. At that point, if the autodetected encoding is different 3365 from the one declared a call to xmlSwitchEncoding() is issued.</li> 3366 <li>If there is no encoding declaration, then the input has to be in either 3367 UTF-8 or UTF-16, if it is not then at some point when processing the 3368 input, the converter/checker of UTF-8 form will raise an encoding error. 3369 You may end-up with a garbled document, or no document at all ! Example: 3370 <pre>~/XML -> /xmllint err.xml 3371err.xml:1: error: Input is not proper UTF-8, indicate encoding ! 3372<tr�s>l�</tr�s> 3373 ^ 3374err.xml:1: error: Bytes: 0xE8 0x73 0x3E 0x6C 3375<tr�s>l�</tr�s> 3376 ^</pre> 3377 </li> 3378 <li>xmlSwitchEncoding() does an encoding name lookup, canonicalize it, and 3379 then search the default registered encoding converters for that encoding. 3380 If it's not within the default set and iconv() support has been compiled 3381 it, it will ask iconv for such an encoder. If this fails then the parser 3382 will report an error and stops processing: 3383 <pre>~/XML -> /xmllint err2.xml 3384err2.xml:1: error: Unsupported encoding UnsupportedEnc 3385<?xml version="1.0" encoding="UnsupportedEnc"?> 3386 ^</pre> 3387 </li> 3388 <li>From that point the encoder processes progressively the input (it is 3389 plugged as a front-end to the I/O module) for that entity. It captures 3390 and converts on-the-fly the document to be parsed to UTF-8. The parser 3391 itself just does UTF-8 checking of this input and process it 3392 transparently. The only difference is that the encoding information has 3393 been added to the parsing context (more precisely to the input 3394 corresponding to this entity).</li> 3395 <li>The result (when using DOM) is an internal form completely in UTF-8 3396 with just an encoding information on the document node.</li> 3397</ol> 3398 3399<p>Ok then what happens when saving the document (assuming you 3400collected/built an xmlDoc DOM like structure) ? It depends on the function 3401called, xmlSaveFile() will just try to save in the original encoding, while 3402xmlSaveFileTo() and xmlSaveFileEnc() can optionally save to a given 3403encoding:</p> 3404<ol> 3405 <li>if no encoding is given, libxml2 will look for an encoding value 3406 associated to the document and if it exists will try to save to that 3407 encoding, 3408 <p>otherwise everything is written in the internal form, i.e. UTF-8</p> 3409 </li> 3410 <li>so if an encoding was specified, either at the API level or on the 3411 document, libxml2 will again canonicalize the encoding name, lookup for a 3412 converter in the registered set or through iconv. If not found the 3413 function will return an error code</li> 3414 <li>the converter is placed before the I/O buffer layer, as another kind of 3415 buffer, then libxml2 will simply push the UTF-8 serialization to through 3416 that buffer, which will then progressively be converted and pushed onto 3417 the I/O layer.</li> 3418 <li>It is possible that the converter code fails on some input, for example 3419 trying to push an UTF-8 encoded Chinese character through the UTF-8 to 3420 ISO-8859-1 converter won't work. Since the encoders are progressive they 3421 will just report the error and the number of bytes converted, at that 3422 point libxml2 will decode the offending character, remove it from the 3423 buffer and replace it with the associated charRef encoding &#123; and 3424 resume the conversion. This guarantees that any document will be saved 3425 without losses (except for markup names where this is not legal, this is 3426 a problem in the current version, in practice avoid using non-ascii 3427 characters for tag or attribute names). A special "ascii" encoding name 3428 is used to save documents to a pure ascii form can be used when 3429 portability is really crucial</li> 3430</ol> 3431 3432<p>Here are a few examples based on the same test document:</p> 3433<pre>~/XML -> /xmllint isolat1 3434<?xml version="1.0" encoding="ISO-8859-1"?> 3435<tr�s>l�</tr�s> 3436~/XML -> /xmllint --encode UTF-8 isolat1 3437<?xml version="1.0" encoding="UTF-8"?> 3438<très>l� �</très> 3439~/XML -> </pre> 3440 3441<p>The same processing is applied (and reuse most of the code) for HTML I18N 3442processing. Looking up and modifying the content encoding is a bit more 3443difficult since it is located in a <meta> tag under the <head>, 3444so a couple of functions htmlGetMetaEncoding() and htmlSetMetaEncoding() have 3445been provided. The parser also attempts to switch encoding on the fly when 3446detecting such a tag on input. Except for that the processing is the same 3447(and again reuses the same code).</p> 3448 3449<h3><a name="Default">Default supported encodings</a></h3> 3450 3451<p>libxml2 has a set of default converters for the following encodings 3452(located in encoding.c):</p> 3453<ol> 3454 <li>UTF-8 is supported by default (null handlers)</li> 3455 <li>UTF-16, both little and big endian</li> 3456 <li>ISO-Latin-1 (ISO-8859-1) covering most western languages</li> 3457 <li>ASCII, useful mostly for saving</li> 3458 <li>HTML, a specific handler for the conversion of UTF-8 to ASCII with HTML 3459 predefined entities like &copy; for the Copyright sign.</li> 3460</ol> 3461 3462<p>More over when compiled on an Unix platform with iconv support the full 3463set of encodings supported by iconv can be instantly be used by libxml. On a 3464linux machine with glibc-2.1 the list of supported encodings and aliases fill 34653 full pages, and include UCS-4, the full set of ISO-Latin encodings, and the 3466various Japanese ones.</p> 3467 3468<h4>Encoding aliases</h4> 3469 3470<p>From 2.2.3, libxml2 has support to register encoding names aliases. The 3471goal is to be able to parse document whose encoding is supported but where 3472the name differs (for example from the default set of names accepted by 3473iconv). The following functions allow to register and handle new aliases for 3474existing encodings. Once registered libxml2 will automatically lookup the 3475aliases when handling a document:</p> 3476<ul> 3477 <li>int xmlAddEncodingAlias(const char *name, const char *alias);</li> 3478 <li>int xmlDelEncodingAlias(const char *alias);</li> 3479 <li>const char * xmlGetEncodingAlias(const char *alias);</li> 3480 <li>void xmlCleanupEncodingAliases(void);</li> 3481</ul> 3482 3483<h3><a name="extend">How to extend the existing support</a></h3> 3484 3485<p>Well adding support for new encoding, or overriding one of the encoders 3486(assuming it is buggy) should not be hard, just write input and output 3487conversion routines to/from UTF-8, and register them using 3488xmlNewCharEncodingHandler(name, xxxToUTF8, UTF8Toxxx), and they will be 3489called automatically if the parser(s) encounter such an encoding name 3490(register it uppercase, this will help). The description of the encoders, 3491their arguments and expected return values are described in the encoding.h 3492header.</p> 3493 3494<p>A quick note on the topic of subverting the parser to use a different 3495internal encoding than UTF-8, in some case people will absolutely want to 3496keep the internal encoding different, I think it's still possible (but the 3497encoding must be compliant with ASCII on the same subrange) though I didn't 3498tried it. The key is to override the default conversion routines (by 3499registering null encoders/decoders for your charsets), and bypass the UTF-8 3500checking of the parser by setting the parser context charset 3501(ctxt->charset) to something different than XML_CHAR_ENCODING_UTF8, but 3502there is no guarantee that this will work. You may also have some troubles 3503saving back.</p> 3504 3505<p>Basically proper I18N support is important, this requires at least 3506libxml-2.0.0, but a lot of features and corrections are really available only 3507starting 2.2.</p> 3508 3509<h2><a name="IO">I/O Interfaces</a></h2> 3510 3511<p>Table of Content:</p> 3512<ol> 3513 <li><a href="#General1">General overview</a></li> 3514 <li><a href="#basic">The basic buffer type</a></li> 3515 <li><a href="#Input">Input I/O handlers</a></li> 3516 <li><a href="#Output">Output I/O handlers</a></li> 3517 <li><a href="#entities">The entities loader</a></li> 3518 <li><a href="#Example2">Example of customized I/O</a></li> 3519</ol> 3520 3521<h3><a name="General1">General overview</a></h3> 3522 3523<p>The module <code><a 3524href="http://xmlsoft.org/html/libxml-xmlio.html">xmlIO.h</a></code> provides 3525the interfaces to the libxml2 I/O system. This consists of 4 main parts:</p> 3526<ul> 3527 <li>Entities loader, this is a routine which tries to fetch the entities 3528 (files) based on their PUBLIC and SYSTEM identifiers. The default loader 3529 don't look at the public identifier since libxml2 do not maintain a 3530 catalog. You can redefine you own entity loader by using 3531 <code>xmlGetExternalEntityLoader()</code> and 3532 <code>xmlSetExternalEntityLoader()</code>. <a href="#entities">Check the 3533 example</a>.</li> 3534 <li>Input I/O buffers which are a commodity structure used by the parser(s) 3535 input layer to handle fetching the informations to feed the parser. This 3536 provides buffering and is also a placeholder where the encoding 3537 converters to UTF8 are piggy-backed.</li> 3538 <li>Output I/O buffers are similar to the Input ones and fulfill similar 3539 task but when generating a serialization from a tree.</li> 3540 <li>A mechanism to register sets of I/O callbacks and associate them with 3541 specific naming schemes like the protocol part of the URIs. 3542 <p>This affect the default I/O operations and allows to use specific I/O 3543 handlers for certain names.</p> 3544 </li> 3545</ul> 3546 3547<p>The general mechanism used when loading http://rpmfind.net/xml.html for 3548example in the HTML parser is the following:</p> 3549<ol> 3550 <li>The default entity loader calls <code>xmlNewInputFromFile()</code> with 3551 the parsing context and the URI string.</li> 3552 <li>the URI string is checked against the existing registered handlers 3553 using their match() callback function, if the HTTP module was compiled 3554 in, it is registered and its match() function will succeeds</li> 3555 <li>the open() function of the handler is called and if successful will 3556 return an I/O Input buffer</li> 3557 <li>the parser will the start reading from this buffer and progressively 3558 fetch information from the resource, calling the read() function of the 3559 handler until the resource is exhausted</li> 3560 <li>if an encoding change is detected it will be installed on the input 3561 buffer, providing buffering and efficient use of the conversion 3562 routines</li> 3563 <li>once the parser has finished, the close() function of the handler is 3564 called once and the Input buffer and associated resources are 3565 deallocated.</li> 3566</ol> 3567 3568<p>The user defined callbacks are checked first to allow overriding of the 3569default libxml2 I/O routines.</p> 3570 3571<h3><a name="basic">The basic buffer type</a></h3> 3572 3573<p>All the buffer manipulation handling is done using the 3574<code>xmlBuffer</code> type define in <code><a 3575href="http://xmlsoft.org/html/libxml-tree.html">tree.h</a> </code>which is a 3576resizable memory buffer. The buffer allocation strategy can be selected to be 3577either best-fit or use an exponential doubling one (CPU vs. memory use 3578trade-off). The values are <code>XML_BUFFER_ALLOC_EXACT</code> and 3579<code>XML_BUFFER_ALLOC_DOUBLEIT</code>, and can be set individually or on a 3580system wide basis using <code>xmlBufferSetAllocationScheme()</code>. A number 3581of functions allows to manipulate buffers with names starting with the 3582<code>xmlBuffer...</code> prefix.</p> 3583 3584<h3><a name="Input">Input I/O handlers</a></h3> 3585 3586<p>An Input I/O handler is a simple structure 3587<code>xmlParserInputBuffer</code> containing a context associated to the 3588resource (file descriptor, or pointer to a protocol handler), the read() and 3589close() callbacks to use and an xmlBuffer. And extra xmlBuffer and a charset 3590encoding handler are also present to support charset conversion when 3591needed.</p> 3592 3593<h3><a name="Output">Output I/O handlers</a></h3> 3594 3595<p>An Output handler <code>xmlOutputBuffer</code> is completely similar to an 3596Input one except the callbacks are write() and close().</p> 3597 3598<h3><a name="entities">The entities loader</a></h3> 3599 3600<p>The entity loader resolves requests for new entities and create inputs for 3601the parser. Creating an input from a filename or an URI string is done 3602through the xmlNewInputFromFile() routine. The default entity loader do not 3603handle the PUBLIC identifier associated with an entity (if any). So it just 3604calls xmlNewInputFromFile() with the SYSTEM identifier (which is mandatory in 3605XML).</p> 3606 3607<p>If you want to hook up a catalog mechanism then you simply need to 3608override the default entity loader, here is an example:</p> 3609<pre>#include <libxml/xmlIO.h> 3610 3611xmlExternalEntityLoader defaultLoader = NULL; 3612 3613xmlParserInputPtr 3614xmlMyExternalEntityLoader(const char *URL, const char *ID, 3615 xmlParserCtxtPtr ctxt) { 3616 xmlParserInputPtr ret; 3617 const char *fileID = NULL; 3618 /* lookup for the fileID depending on ID */ 3619 3620 ret = xmlNewInputFromFile(ctxt, fileID); 3621 if (ret != NULL) 3622 return(ret); 3623 if (defaultLoader != NULL) 3624 ret = defaultLoader(URL, ID, ctxt); 3625 return(ret); 3626} 3627 3628int main(..) { 3629 ... 3630 3631 /* 3632 * Install our own entity loader 3633 */ 3634 defaultLoader = xmlGetExternalEntityLoader(); 3635 xmlSetExternalEntityLoader(xmlMyExternalEntityLoader); 3636 3637 ... 3638}</pre> 3639 3640<h3><a name="Example2">Example of customized I/O</a></h3> 3641 3642<p>This example come from <a href="http://xmlsoft.org/messages/0708.html">a 3643real use case</a>, xmlDocDump() closes the FILE * passed by the application 3644and this was a problem. The <a 3645href="http://xmlsoft.org/messages/0711.html">solution</a> was to redefine a 3646new output handler with the closing call deactivated:</p> 3647<ol> 3648 <li>First define a new I/O output allocator where the output don't close 3649 the file: 3650 <pre>xmlOutputBufferPtr 3651xmlOutputBufferCreateOwn(FILE *file, xmlCharEncodingHandlerPtr encoder) { 3652����xmlOutputBufferPtr ret; 3653���� 3654����if (xmlOutputCallbackInitialized == 0) 3655��������xmlRegisterDefaultOutputCallbacks(); 3656 3657����if (file == NULL) return(NULL); 3658����ret = xmlAllocOutputBuffer(encoder); 3659����if (ret != NULL) { 3660��������ret->context = file; 3661��������ret->writecallback = xmlFileWrite; 3662��������ret->closecallback = NULL; /* No close callback */ 3663����} 3664����return(ret); 3665} </pre> 3666 </li> 3667 <li>And then use it to save the document: 3668 <pre>FILE *f; 3669xmlOutputBufferPtr output; 3670xmlDocPtr doc; 3671int res; 3672 3673f = ... 3674doc = .... 3675 3676output = xmlOutputBufferCreateOwn(f, NULL); 3677res = xmlSaveFileTo(output, doc, NULL); 3678 </pre> 3679 </li> 3680</ol> 3681 3682<h2><a name="Catalog">Catalog support</a></h2> 3683 3684<p>Table of Content:</p> 3685<ol> 3686 <li><a href="General2">General overview</a></li> 3687 <li><a href="#definition">The definition</a></li> 3688 <li><a href="#Simple">Using catalogs</a></li> 3689 <li><a href="#Some">Some examples</a></li> 3690 <li><a href="#reference">How to tune catalog usage</a></li> 3691 <li><a href="#validate">How to debug catalog processing</a></li> 3692 <li><a href="#Declaring">How to create and maintain catalogs</a></li> 3693 <li><a href="#implemento">The implementor corner quick review of the 3694 API</a></li> 3695 <li><a href="#Other">Other resources</a></li> 3696</ol> 3697 3698<h3><a name="General2">General overview</a></h3> 3699 3700<p>What is a catalog? Basically it's a lookup mechanism used when an entity 3701(a file or a remote resource) references another entity. The catalog lookup 3702is inserted between the moment the reference is recognized by the software 3703(XML parser, stylesheet processing, or even images referenced for inclusion 3704in a rendering) and the time where loading that resource is actually 3705started.</p> 3706 3707<p>It is basically used for 3 things:</p> 3708<ul> 3709 <li>mapping from "logical" names, the public identifiers and a more 3710 concrete name usable for download (and URI). For example it can associate 3711 the logical name 3712 <p>"-//OASIS//DTD DocBook XML V4.1.2//EN"</p> 3713 <p>of the DocBook 4.1.2 XML DTD with the actual URL where it can be 3714 downloaded</p> 3715 <p>http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd</p> 3716 </li> 3717 <li>remapping from a given URL to another one, like an HTTP indirection 3718 saying that 3719 <p>"http://www.oasis-open.org/committes/tr.xsl"</p> 3720 <p>should really be looked at</p> 3721 <p>"http://www.oasis-open.org/committes/entity/stylesheets/base/tr.xsl"</p> 3722 </li> 3723 <li>providing a local cache mechanism allowing to load the entities 3724 associated to public identifiers or remote resources, this is a really 3725 important feature for any significant deployment of XML or SGML since it 3726 allows to avoid the aleas and delays associated to fetching remote 3727 resources.</li> 3728</ul> 3729 3730<h3><a name="definition">The definitions</a></h3> 3731 3732<p>Libxml, as of 2.4.3 implements 2 kind of catalogs:</p> 3733<ul> 3734 <li>the older SGML catalogs, the official spec is SGML Open Technical 3735 Resolution TR9401:1997, but is better understood by reading <a 3736 href="http://www.jclark.com/sp/catalog.htm">the SP Catalog page</a> from 3737 James Clark. This is relatively old and not the preferred mode of 3738 operation of libxml.</li> 3739 <li><a href="http://www.oasis-open.org/committees/entity/spec.html">XML 3740 Catalogs</a> is far more flexible, more recent, uses an XML syntax and 3741 should scale quite better. This is the default option of libxml.</li> 3742</ul> 3743 3744<p></p> 3745 3746<h3><a name="Simple">Using catalog</a></h3> 3747 3748<p>In a normal environment libxml2 will by default check the presence of a 3749catalog in /etc/xml/catalog, and assuming it has been correctly populated, 3750the processing is completely transparent to the document user. To take a 3751concrete example, suppose you are authoring a DocBook document, this one 3752starts with the following DOCTYPE definition:</p> 3753<pre><?xml version='1.0'?> 3754<!DOCTYPE book PUBLIC "-//Norman Walsh//DTD DocBk XML V3.1.4//EN" 3755 "http://nwalsh.com/docbook/xml/3.1.4/db3xml.dtd"></pre> 3756 3757<p>When validating the document with libxml, the catalog will be 3758automatically consulted to lookup the public identifier "-//Norman Walsh//DTD 3759DocBk XML V3.1.4//EN" and the system identifier 3760"http://nwalsh.com/docbook/xml/3.1.4/db3xml.dtd", and if these entities have 3761been installed on your system and the catalogs actually point to them, libxml 3762will fetch them from the local disk.</p> 3763 3764<p style="font-size: 10pt"><strong>Note</strong>: Really don't use this 3765DOCTYPE example it's a really old version, but is fine as an example.</p> 3766 3767<p>Libxml2 will check the catalog each time that it is requested to load an 3768entity, this includes DTD, external parsed entities, stylesheets, etc ... If 3769your system is correctly configured all the authoring phase and processing 3770should use only local files, even if your document stays portable because it 3771uses the canonical public and system ID, referencing the remote document.</p> 3772 3773<h3><a name="Some">Some examples:</a></h3> 3774 3775<p>Here is a couple of fragments from XML Catalogs used in libxml2 early 3776regression tests in <code>test/catalogs</code> :</p> 3777<pre><?xml version="1.0"?> 3778<!DOCTYPE catalog PUBLIC 3779 "-//OASIS//DTD Entity Resolution XML Catalog V1.0//EN" 3780 "http://www.oasis-open.org/committees/entity/release/1.0/catalog.dtd"> 3781<catalog xmlns="urn:oasis:names:tc:entity:xmlns:xml:catalog"> 3782 <public publicId="-//OASIS//DTD DocBook XML V4.1.2//EN" 3783 uri="http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd"/> 3784...</pre> 3785 3786<p>This is the beginning of a catalog for DocBook 4.1.2, XML Catalogs are 3787written in XML, there is a specific namespace for catalog elements 3788"urn:oasis:names:tc:entity:xmlns:xml:catalog". The first entry in this 3789catalog is a <code>public</code> mapping it allows to associate a Public 3790Identifier with an URI.</p> 3791<pre>... 3792 <rewriteSystem systemIdStartString="http://www.oasis-open.org/docbook/" 3793 rewritePrefix="file:///usr/share/xml/docbook/"/> 3794...</pre> 3795 3796<p>A <code>rewriteSystem</code> is a very powerful instruction, it says that 3797any URI starting with a given prefix should be looked at another URI 3798constructed by replacing the prefix with an new one. In effect this acts like 3799a cache system for a full area of the Web. In practice it is extremely useful 3800with a file prefix if you have installed a copy of those resources on your 3801local system.</p> 3802<pre>... 3803<delegatePublic publicIdStartString="-//OASIS//DTD XML Catalog //" 3804 catalog="file:///usr/share/xml/docbook.xml"/> 3805<delegatePublic publicIdStartString="-//OASIS//ENTITIES DocBook XML" 3806 catalog="file:///usr/share/xml/docbook.xml"/> 3807<delegatePublic publicIdStartString="-//OASIS//DTD DocBook XML" 3808 catalog="file:///usr/share/xml/docbook.xml"/> 3809<delegateSystem systemIdStartString="http://www.oasis-open.org/docbook/" 3810 catalog="file:///usr/share/xml/docbook.xml"/> 3811<delegateURI uriStartString="http://www.oasis-open.org/docbook/" 3812 catalog="file:///usr/share/xml/docbook.xml"/> 3813...</pre> 3814 3815<p>Delegation is the core features which allows to build a tree of catalogs, 3816easier to maintain than a single catalog, based on Public Identifier, System 3817Identifier or URI prefixes it instructs the catalog software to look up 3818entries in another resource. This feature allow to build hierarchies of 3819catalogs, the set of entries presented should be sufficient to redirect the 3820resolution of all DocBook references to the specific catalog in 3821<code>/usr/share/xml/docbook.xml</code> this one in turn could delegate all 3822references for DocBook 4.2.1 to a specific catalog installed at the same time 3823as the DocBook resources on the local machine.</p> 3824 3825<h3><a name="reference">How to tune catalog usage:</a></h3> 3826 3827<p>The user can change the default catalog behaviour by redirecting queries 3828to its own set of catalogs, this can be done by setting the 3829<code>XML_CATALOG_FILES</code> environment variable to a list of catalogs, an 3830empty one should deactivate loading the default <code>/etc/xml/catalog</code> 3831default catalog</p> 3832 3833<h3><a name="validate">How to debug catalog processing:</a></h3> 3834 3835<p>Setting up the <code>XML_DEBUG_CATALOG</code> environment variable will 3836make libxml2 output debugging informations for each catalog operations, for 3837example:</p> 3838<pre>orchis:~/XML -> xmllint --memory --noout test/ent2 3839warning: failed to load external entity "title.xml" 3840orchis:~/XML -> export XML_DEBUG_CATALOG= 3841orchis:~/XML -> xmllint --memory --noout test/ent2 3842Failed to parse catalog /etc/xml/catalog 3843Failed to parse catalog /etc/xml/catalog 3844warning: failed to load external entity "title.xml" 3845Catalogs cleanup 3846orchis:~/XML -> </pre> 3847 3848<p>The test/ent2 references an entity, running the parser from memory makes 3849the base URI unavailable and the the "title.xml" entity cannot be loaded. 3850Setting up the debug environment variable allows to detect that an attempt is 3851made to load the <code>/etc/xml/catalog</code> but since it's not present the 3852resolution fails.</p> 3853 3854<p>But the most advanced way to debug XML catalog processing is to use the 3855<strong>xmlcatalog</strong> command shipped with libxml2, it allows to load 3856catalogs and make resolution queries to see what is going on. This is also 3857used for the regression tests:</p> 3858<pre>orchis:~/XML -> /xmlcatalog test/catalogs/docbook.xml \ 3859 "-//OASIS//DTD DocBook XML V4.1.2//EN" 3860http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd 3861orchis:~/XML -> </pre> 3862 3863<p>For debugging what is going on, adding one -v flags increase the verbosity 3864level to indicate the processing done (adding a second flag also indicate 3865what elements are recognized at parsing):</p> 3866<pre>orchis:~/XML -> /xmlcatalog -v test/catalogs/docbook.xml \ 3867 "-//OASIS//DTD DocBook XML V4.1.2//EN" 3868Parsing catalog test/catalogs/docbook.xml's content 3869Found public match -//OASIS//DTD DocBook XML V4.1.2//EN 3870http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd 3871Catalogs cleanup 3872orchis:~/XML -> </pre> 3873 3874<p>A shell interface is also available to debug and process multiple queries 3875(and for regression tests):</p> 3876<pre>orchis:~/XML -> /xmlcatalog -shell test/catalogs/docbook.xml \ 3877 "-//OASIS//DTD DocBook XML V4.1.2//EN" 3878> help 3879Commands available: 3880public PublicID: make a PUBLIC identifier lookup 3881system SystemID: make a SYSTEM identifier lookup 3882resolve PublicID SystemID: do a full resolver lookup 3883add 'type' 'orig' 'replace' : add an entry 3884del 'values' : remove values 3885dump: print the current catalog state 3886debug: increase the verbosity level 3887quiet: decrease the verbosity level 3888exit: quit the shell 3889> public "-//OASIS//DTD DocBook XML V4.1.2//EN" 3890http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd 3891> quit 3892orchis:~/XML -> </pre> 3893 3894<p>This should be sufficient for most debugging purpose, this was actually 3895used heavily to debug the XML Catalog implementation itself.</p> 3896 3897<h3><a name="Declaring">How to create and maintain</a> catalogs:</h3> 3898 3899<p>Basically XML Catalogs are XML files, you can either use XML tools to 3900manage them or use <strong>xmlcatalog</strong> for this. The basic step is 3901to create a catalog the -create option provide this facility:</p> 3902<pre>orchis:~/XML -> /xmlcatalog --create tst.xml 3903<?xml version="1.0"?> 3904<!DOCTYPE catalog PUBLIC "-//OASIS//DTD Entity Resolution XML Catalog V1.0//EN" 3905 "http://www.oasis-open.org/committees/entity/release/1.0/catalog.dtd"> 3906<catalog xmlns="urn:oasis:names:tc:entity:xmlns:xml:catalog"/> 3907orchis:~/XML -> </pre> 3908 3909<p>By default xmlcatalog does not overwrite the original catalog and save the 3910result on the standard output, this can be overridden using the -noout 3911option. The <code>-add</code> command allows to add entries in the 3912catalog:</p> 3913<pre>orchis:~/XML -> /xmlcatalog --noout --create --add "public" \ 3914 "-//OASIS//DTD DocBook XML V4.1.2//EN" \ 3915 http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd tst.xml 3916orchis:~/XML -> cat tst.xml 3917<?xml version="1.0"?> 3918<!DOCTYPE catalog PUBLIC "-//OASIS//DTD Entity Resolution XML Catalog V1.0//EN" \ 3919 "http://www.oasis-open.org/committees/entity/release/1.0/catalog.dtd"> 3920<catalog xmlns="urn:oasis:names:tc:entity:xmlns:xml:catalog"> 3921<public publicId="-//OASIS//DTD DocBook XML V4.1.2//EN" 3922 uri="http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd"/> 3923</catalog> 3924orchis:~/XML -> </pre> 3925 3926<p>The <code>-add</code> option will always take 3 parameters even if some of 3927the XML Catalog constructs (like nextCatalog) will have only a single 3928argument, just pass a third empty string, it will be ignored.</p> 3929 3930<p>Similarly the <code>-del</code> option remove matching entries from the 3931catalog:</p> 3932<pre>orchis:~/XML -> /xmlcatalog --del \ 3933 "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd" tst.xml 3934<?xml version="1.0"?> 3935<!DOCTYPE catalog PUBLIC "-//OASIS//DTD Entity Resolution XML Catalog V1.0//EN" 3936 "http://www.oasis-open.org/committees/entity/release/1.0/catalog.dtd"> 3937<catalog xmlns="urn:oasis:names:tc:entity:xmlns:xml:catalog"/> 3938orchis:~/XML -> </pre> 3939 3940<p>The catalog is now empty. Note that the matching of <code>-del</code> is 3941exact and would have worked in a similar fashion with the Public ID 3942string.</p> 3943 3944<p>This is rudimentary but should be sufficient to manage a not too complex 3945catalog tree of resources.</p> 3946 3947<h3><a name="implemento">The implementor corner quick review of the 3948API:</a></h3> 3949 3950<p>First, and like for every other module of libxml, there is an 3951automatically generated <a href="html/libxml-catalog.html">API page for 3952catalog support</a>.</p> 3953 3954<p>The header for the catalog interfaces should be included as:</p> 3955<pre>#include <libxml/catalog.h></pre> 3956 3957<p>The API is voluntarily kept very simple. First it is not obvious that 3958applications really need access to it since it is the default behaviour of 3959libxml2 (Note: it is possible to completely override libxml2 default catalog 3960by using <a href="html/libxml-parser.html">xmlSetExternalEntityLoader</a> to 3961plug an application specific resolver).</p> 3962 3963<p>Basically libxml2 support 2 catalog lists:</p> 3964<ul> 3965 <li>the default one, global shared by all the application</li> 3966 <li>a per-document catalog, this one is built if the document uses the 3967 <code>oasis-xml-catalog</code> PIs to specify its own catalog list, it is 3968 associated to the parser context and destroyed when the parsing context 3969 is destroyed.</li> 3970</ul> 3971 3972<p>the document one will be used first if it exists.</p> 3973 3974<h4>Initialization routines:</h4> 3975 3976<p>xmlInitializeCatalog(), xmlLoadCatalog() and xmlLoadCatalogs() should be 3977used at startup to initialize the catalog, if the catalog should be 3978initialized with specific values xmlLoadCatalog() or xmlLoadCatalogs() 3979should be called before xmlInitializeCatalog() which would otherwise do a 3980default initialization first.</p> 3981 3982<p>The xmlCatalogAddLocal() call is used by the parser to grow the document 3983own catalog list if needed.</p> 3984 3985<h4>Preferences setup:</h4> 3986 3987<p>The XML Catalog spec requires the possibility to select default 3988preferences between public and system delegation, 3989xmlCatalogSetDefaultPrefer() allows this, xmlCatalogSetDefaults() and 3990xmlCatalogGetDefaults() allow to control if XML Catalogs resolution should 3991be forbidden, allowed for global catalog, for document catalog or both, the 3992default is to allow both.</p> 3993 3994<p>And of course xmlCatalogSetDebug() allows to generate debug messages 3995(through the xmlGenericError() mechanism).</p> 3996 3997<h4>Querying routines:</h4> 3998 3999<p>xmlCatalogResolve(), xmlCatalogResolveSystem(), xmlCatalogResolvePublic() 4000and xmlCatalogResolveURI() are relatively explicit if you read the XML 4001Catalog specification they correspond to section 7 algorithms, they should 4002also work if you have loaded an SGML catalog with a simplified semantic.</p> 4003 4004<p>xmlCatalogLocalResolve() and xmlCatalogLocalResolveURI() are the same but 4005operate on the document catalog list</p> 4006 4007<h4>Cleanup and Miscellaneous:</h4> 4008 4009<p>xmlCatalogCleanup() free-up the global catalog, xmlCatalogFreeLocal() is 4010the per-document equivalent.</p> 4011 4012<p>xmlCatalogAdd() and xmlCatalogRemove() are used to dynamically modify the 4013first catalog in the global list, and xmlCatalogDump() allows to dump a 4014catalog state, those routines are primarily designed for xmlcatalog, I'm not 4015sure that exposing more complex interfaces (like navigation ones) would be 4016really useful.</p> 4017 4018<p>The xmlParseCatalogFile() is a function used to load XML Catalog files, 4019it's similar as xmlParseFile() except it bypass all catalog lookups, it's 4020provided because this functionality may be useful for client tools.</p> 4021 4022<h4>threaded environments:</h4> 4023 4024<p>Since the catalog tree is built progressively, some care has been taken to 4025try to avoid troubles in multithreaded environments. The code is now thread 4026safe assuming that the libxml2 library has been compiled with threads 4027support.</p> 4028 4029<p></p> 4030 4031<h3><a name="Other">Other resources</a></h3> 4032 4033<p>The XML Catalog specification is relatively recent so there isn't much 4034literature to point at:</p> 4035<ul> 4036 <li>You can find a good rant from Norm Walsh about <a 4037 href="http://www.arbortext.com/Think_Tank/XML_Resources/Issue_Three/issue_three.html">the 4038 need for catalogs</a>, it provides a lot of context informations even if 4039 I don't agree with everything presented. Norm also wrote a more recent 4040 article <a 4041 href="http://wwws.sun.com/software/xml/developers/resolver/article/">XML 4042 entities and URI resolvers</a> describing them.</li> 4043 <li>An <a href="http://home.ccil.org/~cowan/XML/XCatalog.html">old XML 4044 catalog proposal</a> from John Cowan</li> 4045 <li>The <a href="http://www.rddl.org/">Resource Directory Description 4046 Language</a> (RDDL) another catalog system but more oriented toward 4047 providing metadata for XML namespaces.</li> 4048 <li>the page from the OASIS Technical <a 4049 href="http://www.oasis-open.org/committees/entity/">Committee on Entity 4050 Resolution</a> who maintains XML Catalog, you will find pointers to the 4051 specification update, some background and pointers to others tools 4052 providing XML Catalog support</li> 4053 <li>There is a <a href="buildDocBookCatalog">shell script</a> to generate 4054 XML Catalogs for DocBook 4.1.2 . If it can write to the /etc/xml/ 4055 directory, it will set-up /etc/xml/catalog and /etc/xml/docbook based on 4056 the resources found on the system. Otherwise it will just create 4057 ~/xmlcatalog and ~/dbkxmlcatalog and doing: 4058 <p><code>export XML_CATALOG_FILES=$HOME/xmlcatalog</code></p> 4059 <p>should allow to process DocBook documentations without requiring 4060 network accesses for the DTD or stylesheets</p> 4061 </li> 4062 <li>I have uploaded <a href="ftp://xmlsoft.org/test/dbk412catalog.tar.gz">a 4063 small tarball</a> containing XML Catalogs for DocBook 4.1.2 which seems 4064 to work fine for me too</li> 4065 <li>The <a href="http://www.xmlsoft.org/xmlcatalog_man.html">xmlcatalog 4066 manual page</a></li> 4067</ul> 4068 4069<p>If you have suggestions for corrections or additions, simply contact 4070me:</p> 4071 4072<h2><a name="library">The parser interfaces</a></h2> 4073 4074<p>This section is directly intended to help programmers getting bootstrapped 4075using the XML tollkit from the C language. It is not intended to be 4076extensive. I hope the automatically generated documents will provide the 4077completeness required, but as a separate set of documents. The interfaces of 4078the XML parser are by principle low level, Those interested in a higher level 4079API should <a href="#DOM">look at DOM</a>.</p> 4080 4081<p>The <a href="html/libxml-parser.html">parser interfaces for XML</a> are 4082separated from the <a href="html/libxml-htmlparser.html">HTML parser 4083interfaces</a>. Let's have a look at how the XML parser can be called:</p> 4084 4085<h3><a name="Invoking">Invoking the parser : the pull method</a></h3> 4086 4087<p>Usually, the first thing to do is to read an XML input. The parser accepts 4088documents either from in-memory strings or from files. The functions are 4089defined in "parser.h":</p> 4090<dl> 4091 <dt><code>xmlDocPtr xmlParseMemory(char *buffer, int size);</code></dt> 4092 <dd><p>Parse a null-terminated string containing the document.</p> 4093 </dd> 4094</dl> 4095<dl> 4096 <dt><code>xmlDocPtr xmlParseFile(const char *filename);</code></dt> 4097 <dd><p>Parse an XML document contained in a (possibly compressed) 4098 file.</p> 4099 </dd> 4100</dl> 4101 4102<p>The parser returns a pointer to the document structure (or NULL in case of 4103failure).</p> 4104 4105<h3 id="Invoking1">Invoking the parser: the push method</h3> 4106 4107<p>In order for the application to keep the control when the document is 4108being fetched (which is common for GUI based programs) libxml2 provides a 4109push interface, too, as of version 1.8.3. Here are the interface 4110functions:</p> 4111<pre>xmlParserCtxtPtr xmlCreatePushParserCtxt(xmlSAXHandlerPtr sax, 4112 void *user_data, 4113 const char *chunk, 4114 int size, 4115 const char *filename); 4116int xmlParseChunk (xmlParserCtxtPtr ctxt, 4117 const char *chunk, 4118 int size, 4119 int terminate);</pre> 4120 4121<p>and here is a simple example showing how to use the interface:</p> 4122<pre> FILE *f; 4123 4124 f = fopen(filename, "r"); 4125 if (f != NULL) { 4126 int res, size = 1024; 4127 char chars[1024]; 4128 xmlParserCtxtPtr ctxt; 4129 4130 res = fread(chars, 1, 4, f); 4131 if (res > 0) { 4132 ctxt = xmlCreatePushParserCtxt(NULL, NULL, 4133 chars, res, filename); 4134 while ((res = fread(chars, 1, size, f)) > 0) { 4135 xmlParseChunk(ctxt, chars, res, 0); 4136 } 4137 xmlParseChunk(ctxt, chars, 0, 1); 4138 doc = ctxt->myDoc; 4139 xmlFreeParserCtxt(ctxt); 4140 } 4141 }</pre> 4142 4143<p>The HTML parser embedded into libxml2 also has a push interface; the 4144functions are just prefixed by "html" rather than "xml".</p> 4145 4146<h3 id="Invoking2">Invoking the parser: the SAX interface</h3> 4147 4148<p>The tree-building interface makes the parser memory-hungry, first loading 4149the document in memory and then building the tree itself. Reading a document 4150without building the tree is possible using the SAX interfaces (see SAX.h and 4151<a href="http://www.daa.com.au/~james/gnome/xml-sax/xml-sax.html">James 4152Henstridge's documentation</a>). Note also that the push interface can be 4153limited to SAX: just use the two first arguments of 4154<code>xmlCreatePushParserCtxt()</code>.</p> 4155 4156<h3><a name="Building">Building a tree from scratch</a></h3> 4157 4158<p>The other way to get an XML tree in memory is by building it. Basically 4159there is a set of functions dedicated to building new elements. (These are 4160also described in <libxml/tree.h>.) For example, here is a piece of 4161code that produces the XML document used in the previous examples:</p> 4162<pre> #include <libxml/tree.h> 4163 xmlDocPtr doc; 4164 xmlNodePtr tree, subtree; 4165 4166 doc = xmlNewDoc("1.0"); 4167 doc->children = xmlNewDocNode(doc, NULL, "EXAMPLE", NULL); 4168 xmlSetProp(doc->children, "prop1", "gnome is great"); 4169 xmlSetProp(doc->children, "prop2", "& linux too"); 4170 tree = xmlNewChild(doc->children, NULL, "head", NULL); 4171 subtree = xmlNewChild(tree, NULL, "title", "Welcome to Gnome"); 4172 tree = xmlNewChild(doc->children, NULL, "chapter", NULL); 4173 subtree = xmlNewChild(tree, NULL, "title", "The Linux adventure"); 4174 subtree = xmlNewChild(tree, NULL, "p", "bla bla bla ..."); 4175 subtree = xmlNewChild(tree, NULL, "image", NULL); 4176 xmlSetProp(subtree, "href", "linus.gif");</pre> 4177 4178<p>Not really rocket science ...</p> 4179 4180<h3><a name="Traversing">Traversing the tree</a></h3> 4181 4182<p>Basically by <a href="html/libxml-tree.html">including "tree.h"</a> your 4183code has access to the internal structure of all the elements of the tree. 4184The names should be somewhat simple like <strong>parent</strong>, 4185<strong>children</strong>, <strong>next</strong>, <strong>prev</strong>, 4186<strong>properties</strong>, etc... For example, still with the previous 4187example:</p> 4188<pre><code>doc->children->children->children</code></pre> 4189 4190<p>points to the title element,</p> 4191<pre>doc->children->children->next->children->children</pre> 4192 4193<p>points to the text node containing the chapter title "The Linux 4194adventure".</p> 4195 4196<p><strong>NOTE</strong>: XML allows <em>PI</em>s and <em>comments</em> to be 4197present before the document root, so <code>doc->children</code> may point 4198to an element which is not the document Root Element; a function 4199<code>xmlDocGetRootElement()</code> was added for this purpose.</p> 4200 4201<h3><a name="Modifying">Modifying the tree</a></h3> 4202 4203<p>Functions are provided for reading and writing the document content. Here 4204is an excerpt from the <a href="html/libxml-tree.html">tree API</a>:</p> 4205<dl> 4206 <dt><code>xmlAttrPtr xmlSetProp(xmlNodePtr node, const xmlChar *name, const 4207 xmlChar *value);</code></dt> 4208 <dd><p>This sets (or changes) an attribute carried by an ELEMENT node. 4209 The value can be NULL.</p> 4210 </dd> 4211</dl> 4212<dl> 4213 <dt><code>const xmlChar *xmlGetProp(xmlNodePtr node, const xmlChar 4214 *name);</code></dt> 4215 <dd><p>This function returns a pointer to new copy of the property 4216 content. Note that the user must deallocate the result.</p> 4217 </dd> 4218</dl> 4219 4220<p>Two functions are provided for reading and writing the text associated 4221with elements:</p> 4222<dl> 4223 <dt><code>xmlNodePtr xmlStringGetNodeList(xmlDocPtr doc, const xmlChar 4224 *value);</code></dt> 4225 <dd><p>This function takes an "external" string and converts it to one 4226 text node or possibly to a list of entity and text nodes. All 4227 non-predefined entity references like &Gnome; will be stored 4228 internally as entity nodes, hence the result of the function may not be 4229 a single node.</p> 4230 </dd> 4231</dl> 4232<dl> 4233 <dt><code>xmlChar *xmlNodeListGetString(xmlDocPtr doc, xmlNodePtr list, int 4234 inLine);</code></dt> 4235 <dd><p>This function is the inverse of 4236 <code>xmlStringGetNodeList()</code>. It generates a new string 4237 containing the content of the text and entity nodes. Note the extra 4238 argument inLine. If this argument is set to 1, the function will expand 4239 entity references. For example, instead of returning the &Gnome; 4240 XML encoding in the string, it will substitute it with its value (say, 4241 "GNU Network Object Model Environment").</p> 4242 </dd> 4243</dl> 4244 4245<h3><a name="Saving">Saving a tree</a></h3> 4246 4247<p>Basically 3 options are possible:</p> 4248<dl> 4249 <dt><code>void xmlDocDumpMemory(xmlDocPtr cur, xmlChar**mem, int 4250 *size);</code></dt> 4251 <dd><p>Returns a buffer into which the document has been saved.</p> 4252 </dd> 4253</dl> 4254<dl> 4255 <dt><code>extern void xmlDocDump(FILE *f, xmlDocPtr doc);</code></dt> 4256 <dd><p>Dumps a document to an open file descriptor.</p> 4257 </dd> 4258</dl> 4259<dl> 4260 <dt><code>int xmlSaveFile(const char *filename, xmlDocPtr cur);</code></dt> 4261 <dd><p>Saves the document to a file. In this case, the compression 4262 interface is triggered if it has been turned on.</p> 4263 </dd> 4264</dl> 4265 4266<h3><a name="Compressio">Compression</a></h3> 4267 4268<p>The library transparently handles compression when doing file-based 4269accesses. The level of compression on saves can be turned on either globally 4270or individually for one file:</p> 4271<dl> 4272 <dt><code>int xmlGetDocCompressMode (xmlDocPtr doc);</code></dt> 4273 <dd><p>Gets the document compression ratio (0-9).</p> 4274 </dd> 4275</dl> 4276<dl> 4277 <dt><code>void xmlSetDocCompressMode (xmlDocPtr doc, int mode);</code></dt> 4278 <dd><p>Sets the document compression ratio.</p> 4279 </dd> 4280</dl> 4281<dl> 4282 <dt><code>int xmlGetCompressMode(void);</code></dt> 4283 <dd><p>Gets the default compression ratio.</p> 4284 </dd> 4285</dl> 4286<dl> 4287 <dt><code>void xmlSetCompressMode(int mode);</code></dt> 4288 <dd><p>Sets the default compression ratio.</p> 4289 </dd> 4290</dl> 4291 4292<h2><a name="Entities">Entities or no entities</a></h2> 4293 4294<p>Entities in principle are similar to simple C macros. An entity defines an 4295abbreviation for a given string that you can reuse many times throughout the 4296content of your document. Entities are especially useful when a given string 4297may occur frequently within a document, or to confine the change needed to a 4298document to a restricted area in the internal subset of the document (at the 4299beginning). Example:</p> 4300<pre>1 <?xml version="1.0"?> 43012 <!DOCTYPE EXAMPLE SYSTEM "example.dtd" [ 43023 <!ENTITY xml "Extensible Markup Language"> 43034 ]> 43045 <EXAMPLE> 43056 &xml; 43067 </EXAMPLE></pre> 4307 4308<p>Line 3 declares the xml entity. Line 6 uses the xml entity, by prefixing 4309its name with '&' and following it by ';' without any spaces added. There 4310are 5 predefined entities in libxml2 allowing you to escape characters with 4311predefined meaning in some parts of the xml document content: 4312<strong>&lt;</strong> for the character '<', <strong>&gt;</strong> 4313for the character '>', <strong>&apos;</strong> for the character ''', 4314<strong>&quot;</strong> for the character '"', and 4315<strong>&amp;</strong> for the character '&'.</p> 4316 4317<p>One of the problems related to entities is that you may want the parser to 4318substitute an entity's content so that you can see the replacement text in 4319your application. Or you may prefer to keep entity references as such in the 4320content to be able to save the document back without losing this usually 4321precious information (if the user went through the pain of explicitly 4322defining entities, he may have a a rather negative attitude if you blindly 4323substitute them as saving time). The <a 4324href="html/libxml-parser.html#xmlSubstituteEntitiesDefault">xmlSubstituteEntitiesDefault()</a> 4325function allows you to check and change the behaviour, which is to not 4326substitute entities by default.</p> 4327 4328<p>Here is the DOM tree built by libxml2 for the previous document in the 4329default case:</p> 4330<pre>/gnome/src/gnome-xml -> /xmllint --debug test/ent1 4331DOCUMENT 4332version=1.0 4333 ELEMENT EXAMPLE 4334 TEXT 4335 content= 4336 ENTITY_REF 4337 INTERNAL_GENERAL_ENTITY xml 4338 content=Extensible Markup Language 4339 TEXT 4340 content=</pre> 4341 4342<p>And here is the result when substituting entities:</p> 4343<pre>/gnome/src/gnome-xml -> /tester --debug --noent test/ent1 4344DOCUMENT 4345version=1.0 4346 ELEMENT EXAMPLE 4347 TEXT 4348 content= Extensible Markup Language</pre> 4349 4350<p>So, entities or no entities? Basically, it depends on your use case. I 4351suggest that you keep the non-substituting default behaviour and avoid using 4352entities in your XML document or data if you are not willing to handle the 4353entity references elements in the DOM tree.</p> 4354 4355<p>Note that at save time libxml2 enforces the conversion of the predefined 4356entities where necessary to prevent well-formedness problems, and will also 4357transparently replace those with chars (i.e. it will not generate entity 4358reference elements in the DOM tree or call the reference() SAX callback when 4359finding them in the input).</p> 4360 4361<p><span style="background-color: #FF0000">WARNING</span>: handling entities 4362on top of the libxml2 SAX interface is difficult!!! If you plan to use 4363non-predefined entities in your documents, then the learning curve to handle 4364then using the SAX API may be long. If you plan to use complex documents, I 4365strongly suggest you consider using the DOM interface instead and let libxml 4366deal with the complexity rather than trying to do it yourself.</p> 4367 4368<h2><a name="Namespaces">Namespaces</a></h2> 4369 4370<p>The libxml2 library implements <a 4371href="http://www.w3.org/TR/REC-xml-names/">XML namespaces</a> support by 4372recognizing namespace constructs in the input, and does namespace lookup 4373automatically when building the DOM tree. A namespace declaration is 4374associated with an in-memory structure and all elements or attributes within 4375that namespace point to it. Hence testing the namespace is a simple and fast 4376equality operation at the user level.</p> 4377 4378<p>I suggest that people using libxml2 use a namespace, and declare it in the 4379root element of their document as the default namespace. Then they don't need 4380to use the prefix in the content but we will have a basis for future semantic 4381refinement and merging of data from different sources. This doesn't increase 4382the size of the XML output significantly, but significantly increases its 4383value in the long-term. Example:</p> 4384<pre><mydoc xmlns="http://mydoc.example.org/schemas/"> 4385 <elem1>...</elem1> 4386 <elem2>...</elem2> 4387</mydoc></pre> 4388 4389<p>The namespace value has to be an absolute URL, but the URL doesn't have to 4390point to any existing resource on the Web. It will bind all the element and 4391attributes with that URL. I suggest to use an URL within a domain you 4392control, and that the URL should contain some kind of version information if 4393possible. For example, <code>"http://www.gnome.org/gnumeric/1.0/"</code> is a 4394good namespace scheme.</p> 4395 4396<p>Then when you load a file, make sure that a namespace carrying the 4397version-independent prefix is installed on the root element of your document, 4398and if the version information don't match something you know, warn the user 4399and be liberal in what you accept as the input. Also do *not* try to base 4400namespace checking on the prefix value. <foo:text> may be exactly the 4401same as <bar:text> in another document. What really matters is the URI 4402associated with the element or the attribute, not the prefix string (which is 4403just a shortcut for the full URI). In libxml, element and attributes have an 4404<code>ns</code> field pointing to an xmlNs structure detailing the namespace 4405prefix and its URI.</p> 4406 4407<p>@@Interfaces@@</p> 4408<pre>xmlNodePtr node; 4409if(!strncmp(node->name,"mytag",5) 4410 && node->ns 4411 && !strcmp(node->ns->href,"http://www.mysite.com/myns/1.0")) { 4412 ... 4413}</pre> 4414 4415<p>Usually people object to using namespaces together with validity checking. 4416I will try to make sure that using namespaces won't break validity checking, 4417so even if you plan to use or currently are using validation I strongly 4418suggest adding namespaces to your document. A default namespace scheme 4419<code>xmlns="http://...."</code> should not break validity even on less 4420flexible parsers. Using namespaces to mix and differentiate content coming 4421from multiple DTDs will certainly break current validation schemes. To check 4422such documents one needs to use schema-validation, which is supported in 4423libxml2 as well. See <a href="http://www.relaxng.org/">relagx-ng</a> and <a 4424href="http://www.w3c.org/XML/Schema">w3c-schema</a>.</p> 4425 4426<h2><a name="Upgrading">Upgrading 1.x code</a></h2> 4427 4428<p>Incompatible changes:</p> 4429 4430<p>Version 2 of libxml2 is the first version introducing serious backward 4431incompatible changes. The main goals were:</p> 4432<ul> 4433 <li>a general cleanup. A number of mistakes inherited from the very early 4434 versions couldn't be changed due to compatibility constraints. Example 4435 the "childs" element in the nodes.</li> 4436 <li>Uniformization of the various nodes, at least for their header and link 4437 parts (doc, parent, children, prev, next), the goal is a simpler 4438 programming model and simplifying the task of the DOM implementors.</li> 4439 <li>better conformances to the XML specification, for example version 1.x 4440 had an heuristic to try to detect ignorable white spaces. As a result the 4441 SAX event generated were ignorableWhitespace() while the spec requires 4442 character() in that case. This also mean that a number of DOM node 4443 containing blank text may populate the DOM tree which were not present 4444 before.</li> 4445</ul> 4446 4447<h3>How to fix libxml-1.x code:</h3> 4448 4449<p>So client code of libxml designed to run with version 1.x may have to be 4450changed to compile against version 2.x of libxml. Here is a list of changes 4451that I have collected, they may not be sufficient, so in case you find other 4452change which are required, <a href="mailto:Daniel.Veillard@w3.org">drop me a 4453mail</a>:</p> 4454<ol> 4455 <li>The package name have changed from libxml to libxml2, the library name 4456 is now -lxml2 . There is a new xml2-config script which should be used to 4457 select the right parameters libxml2</li> 4458 <li>Node <strong>childs</strong> field has been renamed 4459 <strong>children</strong> so s/childs/children/g should be applied 4460 (probability of having "childs" anywhere else is close to 0+</li> 4461 <li>The document don't have anymore a <strong>root</strong> element it has 4462 been replaced by <strong>children</strong> and usually you will get a 4463 list of element here. For example a Dtd element for the internal subset 4464 and it's declaration may be found in that list, as well as processing 4465 instructions or comments found before or after the document root element. 4466 Use <strong>xmlDocGetRootElement(doc)</strong> to get the root element of 4467 a document. Alternatively if you are sure to not reference DTDs nor have 4468 PIs or comments before or after the root element 4469 s/->root/->children/g will probably do it.</li> 4470 <li>The white space issue, this one is more complex, unless special case of 4471 validating parsing, the line breaks and spaces usually used for indenting 4472 and formatting the document content becomes significant. So they are 4473 reported by SAX and if your using the DOM tree, corresponding nodes are 4474 generated. Too approach can be taken: 4475 <ol> 4476 <li>lazy one, use the compatibility call 4477 <strong>xmlKeepBlanksDefault(0)</strong> but be aware that you are 4478 relying on a special (and possibly broken) set of heuristics of 4479 libxml to detect ignorable blanks. Don't complain if it breaks or 4480 make your application not 100% clean w.r.t. to it's input.</li> 4481 <li>the Right Way: change you code to accept possibly insignificant 4482 blanks characters, or have your tree populated with weird blank text 4483 nodes. You can spot them using the commodity function 4484 <strong>xmlIsBlankNode(node)</strong> returning 1 for such blank 4485 nodes.</li> 4486 </ol> 4487 <p>Note also that with the new default the output functions don't add any 4488 extra indentation when saving a tree in order to be able to round trip 4489 (read and save) without inflating the document with extra formatting 4490 chars.</p> 4491 </li> 4492 <li>The include path has changed to $prefix/libxml/ and the includes 4493 themselves uses this new prefix in includes instructions... If you are 4494 using (as expected) the 4495 <pre>xml2-config --cflags</pre> 4496 <p>output to generate you compile commands this will probably work out of 4497 the box</p> 4498 </li> 4499 <li>xmlDetectCharEncoding takes an extra argument indicating the length in 4500 byte of the head of the document available for character detection.</li> 4501</ol> 4502 4503<h3>Ensuring both libxml-1.x and libxml-2.x compatibility</h3> 4504 4505<p>Two new version of libxml (1.8.11) and libxml2 (2.3.4) have been released 4506to allow smooth upgrade of existing libxml v1code while retaining 4507compatibility. They offers the following:</p> 4508<ol> 4509 <li>similar include naming, one should use 4510 <strong>#include<libxml/...></strong> in both cases.</li> 4511 <li>similar identifiers defined via macros for the child and root fields: 4512 respectively <strong>xmlChildrenNode</strong> and 4513 <strong>xmlRootNode</strong></li> 4514 <li>a new macro <strong>LIBXML_TEST_VERSION</strong> which should be 4515 inserted once in the client code</li> 4516</ol> 4517 4518<p>So the roadmap to upgrade your existing libxml applications is the 4519following:</p> 4520<ol> 4521 <li>install the libxml-1.8.8 (and libxml-devel-1.8.8) packages</li> 4522 <li>find all occurrences where the xmlDoc <strong>root</strong> field is 4523 used and change it to <strong>xmlRootNode</strong></li> 4524 <li>similarly find all occurrences where the xmlNode 4525 <strong>childs</strong> field is used and change it to 4526 <strong>xmlChildrenNode</strong></li> 4527 <li>add a <strong>LIBXML_TEST_VERSION</strong> macro somewhere in your 4528 <strong>main()</strong> or in the library init entry point</li> 4529 <li>Recompile, check compatibility, it should still work</li> 4530 <li>Change your configure script to look first for xml2-config and fall 4531 back using xml-config . Use the --cflags and --libs output of the command 4532 as the Include and Linking parameters needed to use libxml.</li> 4533 <li>install libxml2-2.3.x and libxml2-devel-2.3.x (libxml-1.8.y and 4534 libxml-devel-1.8.y can be kept simultaneously)</li> 4535 <li>remove your config.cache, relaunch your configuration mechanism, and 4536 recompile, if steps 2 and 3 were done right it should compile as-is</li> 4537 <li>Test that your application is still running correctly, if not this may 4538 be due to extra empty nodes due to formating spaces being kept in libxml2 4539 contrary to libxml1, in that case insert xmlKeepBlanksDefault(1) in your 4540 code before calling the parser (next to 4541 <strong>LIBXML_TEST_VERSION</strong> is a fine place).</li> 4542</ol> 4543 4544<p>Following those steps should work. It worked for some of my own code.</p> 4545 4546<p>Let me put some emphasis on the fact that there is far more changes from 4547libxml 1.x to 2.x than the ones you may have to patch for. The overall code 4548has been considerably cleaned up and the conformance to the XML specification 4549has been drastically improved too. Don't take those changes as an excuse to 4550not upgrade, it may cost a lot on the long term ...</p> 4551 4552<h2><a name="Thread">Thread safety</a></h2> 4553 4554<p>Starting with 2.4.7, libxml2 makes provisions to ensure that concurrent 4555threads can safely work in parallel parsing different documents. There is 4556however a couple of things to do to ensure it:</p> 4557<ul> 4558 <li>configure the library accordingly using the --with-threads options</li> 4559 <li>call xmlInitParser() in the "main" thread before using any of the 4560 libxml2 API (except possibly selecting a different memory allocator)</li> 4561</ul> 4562 4563<p>Note that the thread safety cannot be ensured for multiple threads sharing 4564the same document, the locking must be done at the application level, libxml 4565exports a basic mutex and reentrant mutexes API in <libxml/threads.h>. 4566The parts of the library checked for thread safety are:</p> 4567<ul> 4568 <li>concurrent loading</li> 4569 <li>file access resolution</li> 4570 <li>catalog access</li> 4571 <li>catalog building</li> 4572 <li>entities lookup/accesses</li> 4573 <li>validation</li> 4574 <li>global variables per-thread override</li> 4575 <li>memory handling</li> 4576</ul> 4577 4578<p>XPath is supposed to be thread safe now, but this wasn't tested 4579seriously.</p> 4580 4581<h2><a name="DOM"></a><a name="Principles">DOM Principles</a></h2> 4582 4583<p><a href="http://www.w3.org/DOM/">DOM</a> stands for the <em>Document 4584Object Model</em>; this is an API for accessing XML or HTML structured 4585documents. Native support for DOM in Gnome is on the way (module gnome-dom), 4586and will be based on gnome-xml. This will be a far cleaner interface to 4587manipulate XML files within Gnome since it won't expose the internal 4588structure.</p> 4589 4590<p>The current DOM implementation on top of libxml2 is the <a 4591href="http://cvs.gnome.org/lxr/source/gdome2/">gdome2 Gnome module</a>, this 4592is a full DOM interface, thanks to Paolo Casarini, check the <a 4593href="http://www.cs.unibo.it/~casarini/gdome2/">Gdome2 homepage</a> for more 4594informations.</p> 4595 4596<h2><a name="Example"></a><a name="real">A real example</a></h2> 4597 4598<p>Here is a real size example, where the actual content of the application 4599data is not kept in the DOM tree but uses internal structures. It is based on 4600a proposal to keep a database of jobs related to Gnome, with an XML based 4601storage structure. Here is an <a href="gjobs.xml">XML encoded jobs 4602base</a>:</p> 4603<pre><?xml version="1.0"?> 4604<gjob:Helping xmlns:gjob="http://www.gnome.org/some-location"> 4605 <gjob:Jobs> 4606 4607 <gjob:Job> 4608 <gjob:Project ID="3"/> 4609 <gjob:Application>GBackup</gjob:Application> 4610 <gjob:Category>Development</gjob:Category> 4611 4612 <gjob:Update> 4613 <gjob:Status>Open</gjob:Status> 4614 <gjob:Modified>Mon, 07 Jun 1999 20:27:45 -0400 MET DST</gjob:Modified> 4615 <gjob:Salary>USD 0.00</gjob:Salary> 4616 </gjob:Update> 4617 4618 <gjob:Developers> 4619 <gjob:Developer> 4620 </gjob:Developer> 4621 </gjob:Developers> 4622 4623 <gjob:Contact> 4624 <gjob:Person>Nathan Clemons</gjob:Person> 4625 <gjob:Email>nathan@windsofstorm.net</gjob:Email> 4626 <gjob:Company> 4627 </gjob:Company> 4628 <gjob:Organisation> 4629 </gjob:Organisation> 4630 <gjob:Webpage> 4631 </gjob:Webpage> 4632 <gjob:Snailmail> 4633 </gjob:Snailmail> 4634 <gjob:Phone> 4635 </gjob:Phone> 4636 </gjob:Contact> 4637 4638 <gjob:Requirements> 4639 The program should be released as free software, under the GPL. 4640 </gjob:Requirements> 4641 4642 <gjob:Skills> 4643 </gjob:Skills> 4644 4645 <gjob:Details> 4646 A GNOME based system that will allow a superuser to configure 4647 compressed and uncompressed files and/or file systems to be backed 4648 up with a supported media in the system. This should be able to 4649 perform via find commands generating a list of files that are passed 4650 to tar, dd, cpio, cp, gzip, etc., to be directed to the tape machine 4651 or via operations performed on the filesystem itself. Email 4652 notification and GUI status display very important. 4653 </gjob:Details> 4654 4655 </gjob:Job> 4656 4657 </gjob:Jobs> 4658</gjob:Helping></pre> 4659 4660<p>While loading the XML file into an internal DOM tree is a matter of 4661calling only a couple of functions, browsing the tree to gather the data and 4662generate the internal structures is harder, and more error prone.</p> 4663 4664<p>The suggested principle is to be tolerant with respect to the input 4665structure. For example, the ordering of the attributes is not significant, 4666the XML specification is clear about it. It's also usually a good idea not to 4667depend on the order of the children of a given node, unless it really makes 4668things harder. Here is some code to parse the information for a person:</p> 4669<pre>/* 4670 * A person record 4671 */ 4672typedef struct person { 4673 char *name; 4674 char *email; 4675 char *company; 4676 char *organisation; 4677 char *smail; 4678 char *webPage; 4679 char *phone; 4680} person, *personPtr; 4681 4682/* 4683 * And the code needed to parse it 4684 */ 4685personPtr parsePerson(xmlDocPtr doc, xmlNsPtr ns, xmlNodePtr cur) { 4686 personPtr ret = NULL; 4687 4688DEBUG("parsePerson\n"); 4689 /* 4690 * allocate the struct 4691 */ 4692 ret = (personPtr) malloc(sizeof(person)); 4693 if (ret == NULL) { 4694 fprintf(stderr,"out of memory\n"); 4695 return(NULL); 4696 } 4697 memset(ret, 0, sizeof(person)); 4698 4699 /* We don't care what the top level element name is */ 4700 cur = cur->xmlChildrenNode; 4701 while (cur != NULL) { 4702 if ((!strcmp(cur->name, "Person")) && (cur->ns == ns)) 4703 ret->name = xmlNodeListGetString(doc, cur->xmlChildrenNode, 1); 4704 if ((!strcmp(cur->name, "Email")) && (cur->ns == ns)) 4705 ret->email = xmlNodeListGetString(doc, cur->xmlChildrenNode, 1); 4706 cur = cur->next; 4707 } 4708 4709 return(ret); 4710}</pre> 4711 4712<p>Here are a couple of things to notice:</p> 4713<ul> 4714 <li>Usually a recursive parsing style is the more convenient one: XML data 4715 is by nature subject to repetitive constructs and usually exhibits highly 4716 structured patterns.</li> 4717 <li>The two arguments of type <em>xmlDocPtr</em> and <em>xmlNsPtr</em>, 4718 i.e. the pointer to the global XML document and the namespace reserved to 4719 the application. Document wide information are needed for example to 4720 decode entities and it's a good coding practice to define a namespace for 4721 your application set of data and test that the element and attributes 4722 you're analyzing actually pertains to your application space. This is 4723 done by a simple equality test (cur->ns == ns).</li> 4724 <li>To retrieve text and attributes value, you can use the function 4725 <em>xmlNodeListGetString</em> to gather all the text and entity reference 4726 nodes generated by the DOM output and produce an single text string.</li> 4727</ul> 4728 4729<p>Here is another piece of code used to parse another level of the 4730structure:</p> 4731<pre>#include <libxml/tree.h> 4732/* 4733 * a Description for a Job 4734 */ 4735typedef struct job { 4736 char *projectID; 4737 char *application; 4738 char *category; 4739 personPtr contact; 4740 int nbDevelopers; 4741 personPtr developers[100]; /* using dynamic alloc is left as an exercise */ 4742} job, *jobPtr; 4743 4744/* 4745 * And the code needed to parse it 4746 */ 4747jobPtr parseJob(xmlDocPtr doc, xmlNsPtr ns, xmlNodePtr cur) { 4748 jobPtr ret = NULL; 4749 4750DEBUG("parseJob\n"); 4751 /* 4752 * allocate the struct 4753 */ 4754 ret = (jobPtr) malloc(sizeof(job)); 4755 if (ret == NULL) { 4756 fprintf(stderr,"out of memory\n"); 4757 return(NULL); 4758 } 4759 memset(ret, 0, sizeof(job)); 4760 4761 /* We don't care what the top level element name is */ 4762 cur = cur->xmlChildrenNode; 4763 while (cur != NULL) { 4764 4765 if ((!strcmp(cur->name, "Project")) && (cur->ns == ns)) { 4766 ret->projectID = xmlGetProp(cur, "ID"); 4767 if (ret->projectID == NULL) { 4768 fprintf(stderr, "Project has no ID\n"); 4769 } 4770 } 4771 if ((!strcmp(cur->name, "Application")) && (cur->ns == ns)) 4772 ret->application = xmlNodeListGetString(doc, cur->xmlChildrenNode, 1); 4773 if ((!strcmp(cur->name, "Category")) && (cur->ns == ns)) 4774 ret->category = xmlNodeListGetString(doc, cur->xmlChildrenNode, 1); 4775 if ((!strcmp(cur->name, "Contact")) && (cur->ns == ns)) 4776 ret->contact = parsePerson(doc, ns, cur); 4777 cur = cur->next; 4778 } 4779 4780 return(ret); 4781}</pre> 4782 4783<p>Once you are used to it, writing this kind of code is quite simple, but 4784boring. Ultimately, it could be possible to write stubbers taking either C 4785data structure definitions, a set of XML examples or an XML DTD and produce 4786the code needed to import and export the content between C data and XML 4787storage. This is left as an exercise to the reader :-)</p> 4788 4789<p>Feel free to use <a href="example/gjobread.c">the code for the full C 4790parsing example</a> as a template, it is also available with Makefile in the 4791Gnome CVS base under gnome-xml/example</p> 4792 4793<h2><a name="Contributi">Contributions</a></h2> 4794<ul> 4795 <li>Bjorn Reese, William Brack and Thomas Broyer have provided a number of 4796 patches, Gary Pennington worked on the validation API, threading support 4797 and Solaris port.</li> 4798 <li>John Fleck helps maintaining the documentation and man pages.</li> 4799 <li><a href="mailto:igor@zlatkovic.com">Igor Zlatkovic</a> is now the 4800 maintainer of the Windows port, <a 4801 href="http://www.zlatkovic.com/projects/libxml/index.html">he provides 4802 binaries</a></li> 4803 <li><a href="mailto:Gary.Pennington@sun.com">Gary Pennington</a> provides 4804 <a href="http://garypennington.net/libxml2/">Solaris binaries</a></li> 4805 <li><a 4806 href="http://mail.gnome.org/archives/xml/2001-March/msg00014.html">Matt 4807 Sergeant</a> developed <a 4808 href="http://axkit.org/download/">XML::LibXSLT</a>, a Perl wrapper for 4809 libxml2/libxslt as part of the <a href="http://axkit.com/">AxKit XML 4810 application server</a></li> 4811 <li><a href="mailto:fnatter@gmx.net">Felix Natter</a> and <a 4812 href="mailto:geertk@ai.rug.nl">Geert Kloosterman</a> provide <a 4813 href="libxml-doc.el">an emacs module</a> to lookup libxml(2) functions 4814 documentation</li> 4815 <li><a href="mailto:sherwin@nlm.nih.gov">Ziying Sherwin</a> provided <a 4816 href="http://xmlsoft.org/messages/0488.html">man pages</a></li> 4817 <li>there is a module for <a 4818 href="http://acs-misc.sourceforge.net/nsxml.html">libxml/libxslt support 4819 in OpenNSD/AOLServer</a></li> 4820 <li><a href="mailto:dkuhlman@cutter.rexx.com">Dave Kuhlman</a> provided the 4821 first version of libxml/libxslt <a 4822 href="http://www.rexx.com/~dkuhlman">wrappers for Python</a></li> 4823 <li>Petr Kozelka provides <a 4824 href="http://sourceforge.net/projects/libxml2-pas">Pascal units to glue 4825 libxml2</a> with Kylix and Delphi and other Pascal compilers</li> 4826 <li><a href="mailto:aleksey@aleksey.com">Aleksey Sanin</a> implemented the 4827 <a href="http://www.w3.org/Signature/">XML Canonicalization and XML 4828 Digital Signature</a> <a 4829 href="http://www.aleksey.com/xmlsec/">implementations for libxml2</a></li> 4830 <li><a href="mailto:Steve.Ball@explain.com.au">Steve Ball</a> 4831 and contributors maintain <a 4832 href="http://tclxml.sourceforge.net/">tcl bindings for libxml2 and 4833 libxslt</a>, as well as <a 4834 href="http://tclxml.sf.net/tkxmllint.html">tkxmllint</a> a GUI for 4835 xmllint and <a href="http://tclxml.sf.net/tkxsltproc.html">tkxsltproc</a> 4836 a GUI for xsltproc.</li> 4837</ul> 4838 4839<p></p> 4840</body> 4841</html> 4842
