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<title>6.5 statcache -- An optimization of os.stat()</title>
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<H1><A NAME="SECTION008500000000000000000">
6.5 <tt class="module">statcache</tt> --
         An optimization of <tt class="function">os.stat()</tt></A>
</H1>

<P>
<A NAME="module-statcache"></A>

<P>
<div class="versionnote"><b>Deprecated since release 2.2.</b>
Use <tt class="function"><tt class="module"><a href="module-os.html">os</a></tt>.stat()</tt> directly instead
of using the cache; the cache introduces a very high level of
fragility in applications using it and complicates application code
with the addition of cache management support.</div><p></p>

<P>
The <tt class="module">statcache</tt> module provides a simple optimization to
<tt class="function">os.stat()</tt>: remembering the values of previous invocations.

<P>
The <tt class="module">statcache</tt> module defines the following functions:

<P>
<dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline">
  <td><nobr><b><tt id='l2h-1796' xml:id='l2h-1796' class="function">stat</tt></b>(</nobr></td>
  <td><var>path</var>)</td></tr></table></dt>
<dd>
This is the main module entry-point.
Identical for <tt class="function">os.stat()</tt>, except for remembering the result
for future invocations of the function.
</dl>

<P>
The rest of the functions are used to clear the cache, or parts of
it.

<P>
<dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline">
  <td><nobr><b><tt id='l2h-1797' xml:id='l2h-1797' class="function">reset</tt></b>(</nobr></td>
  <td><var></var>)</td></tr></table></dt>
<dd>
Clear the cache: forget all results of previous <tt class="function">stat()</tt>
calls.
</dl>

<P>
<dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline">
  <td><nobr><b><tt id='l2h-1798' xml:id='l2h-1798' class="function">forget</tt></b>(</nobr></td>
  <td><var>path</var>)</td></tr></table></dt>
<dd>
Forget the result of <code>stat(<var>path</var>)</code>, if any.
</dl>

<P>
<dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline">
  <td><nobr><b><tt id='l2h-1799' xml:id='l2h-1799' class="function">forget_prefix</tt></b>(</nobr></td>
  <td><var>prefix</var>)</td></tr></table></dt>
<dd>
Forget all results of <code>stat(<var>path</var>)</code> for <var>path</var> starting
with <var>prefix</var>.
</dl>

<P>
<dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline">
  <td><nobr><b><tt id='l2h-1800' xml:id='l2h-1800' class="function">forget_dir</tt></b>(</nobr></td>
  <td><var>prefix</var>)</td></tr></table></dt>
<dd>
Forget all results of <code>stat(<var>path</var>)</code> for <var>path</var> a file in
the directory <var>prefix</var>, including <code>stat(<var>prefix</var>)</code>.
</dl>

<P>
<dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline">
  <td><nobr><b><tt id='l2h-1801' xml:id='l2h-1801' class="function">forget_except_prefix</tt></b>(</nobr></td>
  <td><var>prefix</var>)</td></tr></table></dt>
<dd>
Similar to <tt class="function">forget_prefix()</tt>, but for all <var>path</var> values
<em>not</em> starting with <var>prefix</var>.
</dl>

<P>
Example:

<P>
<div class="verbatim"><pre>
&gt;&gt;&gt; import os, statcache
&gt;&gt;&gt; statcache.stat('.')
(16893, 2049, 772, 18, 1000, 1000, 2048, 929609777, 929609777, 929609777)
&gt;&gt;&gt; os.stat('.')
(16893, 2049, 772, 18, 1000, 1000, 2048, 929609777, 929609777, 929609777)
</pre></div>

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<span class="release-info">Release 2.4.2, documentation updated on 28 September 2005.</span>
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