Reduce ram used for very large inlined index files
During a clone, an inline index is not converted to a split index
file until the very end. When the conversion happens, the index
can be very large, and the inline index loading functions always load
the entire index file into ram.
This changes the revlog code to read the index in smaller chunks.
<table class="logEntry parity#parity#">
<tr>
<th class="age">#date|age# ago:</th>
<th class="firstline">#desc|strip|firstline|escape#</th>
</tr>
<tr>
<th class="revision">changeset #rev#:</th>
<td class="node"><a href="?cs=#node|short#">#node|short#</a></td>
</tr>
#parent%changelogparent#
#child%changelogchild#
#changelogtag#
<tr>
<th class="author">author:</th>
<td class="author">#author|obfuscate#</td>
</tr>
<tr>
<th class="date">date:</th>
<td class="date">#date|date#</td>
</tr>
<tr>
<th class="files"><a href="?mf=#manifest|short#;path=/">files</a>:</th>
<td class="files">#files#</td>
</tr>
</table>