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254<table class="navigation" cellpadding="0" cellspacing="0" 11<table class="navigation" cellpadding="0" cellspacing="0"
255 width="100%" border="0"> 12 width="100%" border="0">
256<tr><td class="navicon" width="150" height="35"> 13<tr><td class="navicon" width="150" height="35">
257<a href="http://www.gentoo.org/" title="Gentoo Linux Home Page"> 14<a href="http://www.gentoo.org/" title="Gentoo Linux Home Page">
268<tbody valign="top"> 25<tbody valign="top">
269<tr class="field"><th class="field-name">GLEP:</th><td class="field-body">55</td> 26<tr class="field"><th class="field-name">GLEP:</th><td class="field-body">55</td>
270</tr> 27</tr>
271<tr class="field"><th class="field-name">Title:</th><td class="field-body">Use EAPI-suffixed ebuilds (.ebuild-EAPI)</td> 28<tr class="field"><th class="field-name">Title:</th><td class="field-body">Use EAPI-suffixed ebuilds (.ebuild-EAPI)</td>
272</tr> 29</tr>
273<tr class="field"><th class="field-name">Version:</th><td class="field-body">1.3</td> 30<tr class="field"><th class="field-name">Version:</th><td class="field-body">1.5</td>
274</tr> 31</tr>
275<tr class="field"><th class="field-name">Last-Modified:</th><td class="field-body"><a class="reference external" href="http://www.gentoo.org/cgi-bin/viewcvs.cgi/xml/htdocs/proj/en/glep/glep-0055.txt?cvsroot=gentoo">2009/05/17 15:50:27</a></td> 32<tr class="field"><th class="field-name">Last-Modified:</th><td class="field-body"><a class="reference external" href="http://www.gentoo.org/cgi-bin/viewcvs.cgi/xml/htdocs/proj/en/glep/glep-0055.txt?cvsroot=gentoo">2009/05/17 20:56:53</a></td>
276</tr> 33</tr>
277<tr class="field"><th class="field-name">Author:</th><td class="field-body">Piotr Jaroszyński &lt;peper&#32;&#97;t&#32;gentoo.org&gt;</td> 34<tr class="field"><th class="field-name">Author:</th><td class="field-body">Piotr Jaroszyński &lt;peper&#32;&#97;t&#32;gentoo.org&gt;</td>
278</tr> 35</tr>
279<tr class="field"><th class="field-name">Status:</th><td class="field-body">Draft</td> 36<tr class="field"><th class="field-name">Status:</th><td class="field-body">Draft</td>
280</tr> 37</tr>
382 139
383!!! All ebuilds that could satisfy &quot;sys-apps/foo&quot; have been masked. 140!!! All ebuilds that could satisfy &quot;sys-apps/foo&quot; have been masked.
384!!! One of the following masked packages is required to complete your request: 141!!! One of the following masked packages is required to complete your request:
385- sys-apps/foo-1 (masked by: corruption) 142- sys-apps/foo-1 (masked by: corruption)
386</pre> 143</pre>
387<p>Current portage looks for eclasses only in the <tt class="docutils literal"><span class="pre">eclass</span></tt> directory of a 144<p>Current portage looks for eclasses only in the <tt class="docutils literal">eclass</tt> directory of a
388repository. This results in a fatal error and ebuild being masked by corruption 145repository. This results in a fatal error and ebuild being masked by corruption
389- might be pretty confusing to users.</p> 146- might be pretty confusing to users.</p>
390</div> 147</div>
391<div class="section" id="new-global-scope-function"> 148<div class="section" id="new-global-scope-function">
392<h2><a class="toc-backref" href="#id7">New global scope function</a></h2> 149<h2><a class="toc-backref" href="#id7">New global scope function</a></h2>
423</pre> 180</pre>
424<p>Not the best error message, especially if there are lots of them.</p> 181<p>Not the best error message, especially if there are lots of them.</p>
425</div> 182</div>
426<div class="section" id="use-newer-bash-features"> 183<div class="section" id="use-newer-bash-features">
427<h2><a class="toc-backref" href="#id9">Use newer bash features</a></h2> 184<h2><a class="toc-backref" href="#id9">Use newer bash features</a></h2>
428<p><tt class="docutils literal"><span class="pre">|&amp;</span></tt> is a new type of redirection added in bash-4. It cannot be used even in 185<p><tt class="docutils literal">|&amp;</tt> is a new type of redirection added in bash-4. It cannot be used even in
429local scope as bash still parses the whole ebuild.</p> 186local scope as bash still parses the whole ebuild.</p>
430<p><tt class="docutils literal"><span class="pre">sys-apps/foo-1.ebuild</span></tt>:</p> 187<p><tt class="docutils literal"><span class="pre">sys-apps/foo-1.ebuild</span></tt>:</p>
431<pre class="literal-block"> 188<pre class="literal-block">
432EAPI=&quot;5&quot; 189EAPI=&quot;5&quot;
433 190
473<div class="section" id="proposed-solution"> 230<div class="section" id="proposed-solution">
474<h1><a class="toc-backref" href="#id11">Proposed solution</a></h1> 231<h1><a class="toc-backref" href="#id11">Proposed solution</a></h1>
475<p>The proposed solution is to use EAPI-suffixed file extensions for ebuilds. This 232<p>The proposed solution is to use EAPI-suffixed file extensions for ebuilds. This
476allows package managers to trivially read the EAPI from the ebuild filename. It 233allows package managers to trivially read the EAPI from the ebuild filename. It
477is also backwards compatible, because currently ebuilds are recognised by the 234is also backwards compatible, because currently ebuilds are recognised by the
478<tt class="docutils literal"><span class="pre">.ebuild</span></tt> file extension and hence EAPI-suffixed ebuilds are simply ignored by 235<tt class="docutils literal">.ebuild</tt> file extension and hence EAPI-suffixed ebuilds are simply ignored by
479the package managers.</p> 236the package managers.</p>
480</div> 237</div>
481<div class="section" id="specification"> 238<div class="section" id="specification">
482<h1><a class="toc-backref" href="#id12">Specification</a></h1> 239<h1><a class="toc-backref" href="#id12">Specification</a></h1>
483<p>Ebuild filename extension syntax: <tt class="docutils literal"><span class="pre">ebuild[-&lt;EAPI&gt;]</span></tt>, where <tt class="docutils literal"><span class="pre">[]</span></tt> denotes an 240<p>Ebuild filename extension syntax: <tt class="docutils literal"><span class="pre">ebuild[-&lt;EAPI&gt;]</span></tt>, where <tt class="docutils literal">[]</tt> denotes an
484optional part, and <tt class="docutils literal"><span class="pre">&lt;EAPI&gt;</span></tt> is the EAPI of the ebuild.</p> 241optional part, and <tt class="docutils literal">&lt;EAPI&gt;</tt> is the EAPI of the ebuild.</p>
485<p>The EAPI used by the ebuild is the EAPI included in the filename if it is set. 242<p>The EAPI used by the ebuild is the EAPI included in the filename if it is set.
486Otherwise the EAPI set inside the ebuild is used, which defaults to 0 (this is 243Otherwise the EAPI set inside the ebuild is used, which defaults to 0 (this is
487the current behaviour).</p> 244the current behaviour).</p>
488<p>Ebuilds with unsupported EAPIs are masked.</p> 245<p>Ebuilds with unsupported EAPIs are masked.</p>
489<p>It should be considered an error to set the EAPI both in the filename and in the 246<p>It should be considered an error to set the EAPI both in the filename and in the
516allowing authors to provide backwards compatible ebuilds, it would introduce 273allowing authors to provide backwards compatible ebuilds, it would introduce
517problems too. The first is the requirement to have strict EAPI ordering, the 274problems too. The first is the requirement to have strict EAPI ordering, the
518second is ensuring that all the ebuilds for a single category/package-version 275second is ensuring that all the ebuilds for a single category/package-version
519are equivalent, i.e. installing any of them has exactly the same effect on a 276are equivalent, i.e. installing any of them has exactly the same effect on a
520given system.</p> 277given system.</p>
278<p>Also note that it is not a new restriction. It is already possible to illegally
279have multiple versions with different EAPIs as e.g. <tt class="docutils literal">1.0 == 1.00 == <span class="pre">1.00-r0</span></tt>
280and hence you could have <tt class="docutils literal"><span class="pre">foo-1.0.ebuild</span></tt> with EAPI X and <tt class="docutils literal"><span class="pre">foo-1.00.ebuild</span></tt>
281with EAPI Y.</p>
521</div> 282</div>
522<div class="section" id="summary-of-ideas"> 283<div class="section" id="summary-of-ideas">
523<h1><a class="toc-backref" href="#id13">Summary of ideas</a></h1> 284<h1><a class="toc-backref" href="#id13">Summary of ideas</a></h1>
524<div class="section" id="eapi-suffixed-ebuilds-proposed-solution"> 285<div class="section" id="eapi-suffixed-ebuilds-proposed-solution">
525<h2><a class="toc-backref" href="#id14">EAPI-suffixed ebuilds (proposed solution)</a></h2> 286<h2><a class="toc-backref" href="#id14">EAPI-suffixed ebuilds (proposed solution)</a></h2>
562behaviour section for old package managers.</p> 323behaviour section for old package managers.</p>
563<p>Performance decrease comes from the fact that with version format changes in the 324<p>Performance decrease comes from the fact that with version format changes in the
564picture package managers need EAPI to parse the ebuild's version. That means that merely 325picture package managers need EAPI to parse the ebuild's version. That means that merely
565picking the best version of a package requires loading EAPI (from cache or the 326picking the best version of a package requires loading EAPI (from cache or the
566ebuild) for each available ebuild.</p> 327ebuild) for each available ebuild.</p>
328<p>Here is more or less how the package manager figures out the best available
329version for a package with N versions available.</p>
330<blockquote>
331<ul class="simple">
332<li>EAPI in the filename<ul>
333<li>Read the directory containing the package - readdir()</li>
334<li>For each ebuild, read its EAPI and using that parse its version - no I/O</li>
335<li>Sort the versions - no I/O</li>
336<li>Going down from the highest to the lowest version<ul>
337<li>Get the metadata from cache - 2 x stat() + read()</li>
338<li>break if the version is visible</li>
339</ul>
340</li>
341</ul>
342</li>
343<li>EAPI in the ebuild<ul>
344<li>Read the directory containing the package - readdir()</li>
345<li>For each ebuild load its metadata from cache to get its EAPI - N x (2 x stat() + read())</li>
346<li>Sort the versions - no I/O</li>
347<li>Going down from the highest to the lowest version<ul>
348<li>(metadata is already loaded) - no I/O</li>
349<li>break if the version is visible - no I/O</li>
350</ul>
351</li>
352</ul>
353</li>
354</ul>
355</blockquote>
356<p>The difference is in for how many versions the package manager needs to hit
357cache. With EAPI in the ebuild it needs to do that for all versions, with EAPI
358in the filename it depends on versions visibility.
359For example, package foo has versions 1, 2, 3, 4, 5 and 6. 6 is masked, 5 is
360~arch and 1,2,3 and 4 are arch. Say, the user accepts only arch for this
361package. With EAPI in the filename it will read metadata only for versions
3626, 5 and 4. With EAPI in the ebuild it needs to load metadata for all versions.</p>
363<p>It's hard to say what's the avarage case, but surely the worst case scenario
364(when only the lowest version is visible) is uncommon.</p>
567</div> 365</div>
568<div class="section" id="easily-fetchable-eapi-inside-the-ebuild-and-one-time-extension-change"> 366<div class="section" id="easily-fetchable-eapi-inside-the-ebuild-and-one-time-extension-change">
569<h2><a class="toc-backref" href="#id17">Easily fetchable EAPI inside the ebuild and one-time extension change</a></h2> 367<h2><a class="toc-backref" href="#id17">Easily fetchable EAPI inside the ebuild and one-time extension change</a></h2>
570<dl class="docutils"> 368<dl class="docutils">
571<dt>Properties:</dt> 369<dt>Properties:</dt>
619 417
620</div> 418</div>
621<div class="footer"> 419<div class="footer">
622<hr class="footer" /> 420<hr class="footer" />
623<a class="reference external" href="glep-0055.txt">View document source</a>. 421<a class="reference external" href="glep-0055.txt">View document source</a>.
624Generated on: 2009-05-17 16:58 UTC. 422Generated on: 2010-04-07 22:12 UTC.
625Generated by <a class="reference external" href="http://docutils.sourceforge.net/">Docutils</a> from <a class="reference external" href="http://docutils.sourceforge.net/rst.html">reStructuredText</a> source. 423Generated by <a class="reference external" href="http://docutils.sourceforge.net/">Docutils</a> from <a class="reference external" href="http://docutils.sourceforge.net/rst.html">reStructuredText</a> source.
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