dirstate walking optimizations
The repo walking code introduces a number of calls to dirstate.map.copy(),
significantly slowing down the walk on large trees. When a list of
files is passed to the walking code, we should only look at map entries
relevant to the file list passed in.
dirstate.filterfiles() is added to return a subset of the dirstate map.
The subset includes in files passed in, and if one of the files requested
is actually a directory, it includes any files inside that directory tree.
This brings the time for hg diff Makefile down from 1.7s to .3s on
a linux kernel repo.
Also, the diff command was unconditionally calling makewalk, leading
to an extra pass through repo.changes. This patch avoids the call
to makewalk when commands.diff isn't given a list of patterns, cutting
the time for hg diff (with no args) in half.
Index: mine/mercurial/hg.py
===================================================================
<table class="parity#parity#" width="100%" cellspacing="0" cellpadding="0">
<tr>
<td align="right" width="15%"><b>#date|age# ago: </b></td>
<td><b><a href="?cmd=changeset;node=#node#">#desc|firstline|escape#</a></b></td></tr>
<tr>
<td align="right">revision #filerev#: </td>
<td><a href="?cmd=file;file=#file#;filenode=#filenode#">#filenode|short#</a>
<a href="?cmd=filediff;file=#file#;node=#node#">(diff)</a>
<a href="?cmd=annotate;file=#file#;filenode=#filenode#">(annotate)</a>
</td></tr>
<tr>
<td align="right">author: </td>
<td>#author|obfuscate#</td></tr>
<tr>
<td align="right">date: </td>
<td>#date|date# (#date|age# ago)</td></tr>
</table>