<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title>Inside the Working Copy Administration Area</title><link rel="stylesheet" href="styles.css" type="text/css" /><meta name="generator" content="DocBook XSL Stylesheets V1.73.2" /><link rel="start" href="index.html" title="Version Control with Subversion" /><link rel="up" href="svn.developer.html" title="Chapter 8. Embedding Subversion" /><link rel="prev" href="svn.developer.layerlib.html" title="Layered Library Design" /><link rel="next" href="svn.developer.usingapi.html" title="Using the APIs" /></head><body><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">Inside the Working Copy Administration Area</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="svn.developer.layerlib.html">Prev</a> </td><th width="60%" align="center">Chapter 8. Embedding Subversion</th><td width="20%" align="right"> <a accesskey="n" href="svn.developer.usingapi.html">Next</a></td></tr></table><hr /></div><div class="sect1" lang="en" xml:lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="svn.developer.insidewc"></a>Inside the Working Copy Administration Area</h2></div></div></div><p>As we mentioned earlier, each directory of a Subversion
working copy contains a special subdirectory called
<code class="filename">.svn</code> which houses administrative data about
that working copy directory. Subversion uses the information in
<code class="filename">.svn</code> to keep track of things like:</p><div class="itemizedlist"><ul type="disc"><li><p>Which repository location(s) are represented by the
files and subdirectories in the working copy
directory.</p></li><li><p>What revision of each of those files and directories are
currently present in the working copy.</p></li><li><p>Any user-defined properties that might be attached
to those files and directories.</p></li><li><p>Pristine (un-edited) copies of the working copy
files.</p></li></ul></div><p>The Subversion working copy administration area's layout and
contents are considered implementation details not really
intended for human consumption. Developers are encouraged to
use Subversion's public APIs, or the tools that Subversion provides, to access and
manipulate the working copy data, instead of directly reading
or modifying those files. The file formats employed by the working
copy library for its administrative data do change from time to
time—a fact that the public APIs do a great job of
hiding from the average user. In this section, we
expose some of these implementation details sheerly to appease
your overwhelming curiosity.</p><div class="sect2" lang="en" xml:lang="en"><div class="titlepage"><div><div><h3 class="title"><a id="svn.developer.insidewc.entries"></a>The Entries File</h3></div></div></div><p>Perhaps the single most important file in the
<code class="filename">.svn</code> directory is the
<code class="filename">entries</code> file. It
contains the bulk of the administrative
information about the versioned items in a working copy
directory. It is this one file which tracks the repository
URLs, pristine revision, file checksums, pristine text and
property timestamps, scheduling and conflict state
information, last-known commit information (author, revision,
timestamp), local copy history—practically everything
that a Subversion client is interested in knowing about a
versioned (or to-be-versioned) resource!</p><p>Folks familiar with CVS's administrative directories will
have recognized at this point that Subversion's
<code class="filename">.svn/entries</code> file serves the purposes of,
among other things, CVS's <code class="filename">CVS/Entries</code>,
<code class="filename">CVS/Root</code>, and
<code class="filename">CVS/Repository</code> files combined.</p><p>The format of the <code class="filename">.svn/entries</code> file
has changed over time. Originally an XML file, it now uses a
custom—though still human-readable—file format.
While XML was a great choice for early developers of
Subversion who were frequently debugging the file's contents
(and Subversion's behavior in light of them), the need for
easy developer debugging has diminished as Subversion has
matured, and has been replaced by the user's need for snappier
performance. Be aware that Subversion's working copy library
automatically upgrades working copies from one format to
another—it reads the old formats, and writes the
new—which saves you the hassle of checking out a new
working copy, but can also complicate situations where
different versions of Subversion might be trying to use the
same working copy.</p></div><div class="sect2" lang="en" xml:lang="en"><div class="titlepage"><div><div><h3 class="title"><a id="svn.developer.insidewc.base-and-props"></a>Pristine Copies and Property Files</h3></div></div></div><p>As mentioned before, the <code class="filename">.svn</code>
directory also holds the pristine “<span class="quote">text-base</span>”
versions of files. Those can be found in
<code class="filename">.svn/text-base</code>. The benefits of these
pristine copies are multiple—network-free checks for
local modifications and difference reporting, network-free
reversion of modified or missing files, more efficient transmission
of changes to the server—but comes at the cost of having
each versioned file stored at least twice on disk. These
days, this seems to be a negligible penalty for most files.
However, the situation gets uglier as the size of your
versioned files grows. Some attention is being given to
making the presence of the “<span class="quote">text-base</span>” an option.
Ironically though, it is as your versioned files' sizes get
larger that the existence of the “<span class="quote">text-base</span>”
becomes more crucial—who wants to transmit a huge file
across a network just because they want to commit a tiny
change to it?</p><p>Similar in purpose to the “<span class="quote">text-base</span>” files
are the property files and their pristine
“<span class="quote">prop-base</span>” copies, located in
<code class="filename">.svn/props</code> and
<code class="filename">.svn/prop-base</code> respectively. Since
directories can have properties, too, there are also
<code class="filename">.svn/dir-props</code> and
<code class="filename">.svn/dir-prop-base</code> files.</p></div></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="svn.developer.layerlib.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="svn.developer.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="svn.developer.usingapi.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">Layered Library Design </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> Using the APIs</td></tr></table></div></body></html>
