revlog: add a magic null revision to our index
We expand our index by one entry so that index[nullrev] points to a
unique entry, the null revision. This naturally eliminates numerous
extra tests in the performance-sensitive index access functions, most
of which are now trivial again.
Adding new entries is now done with insert(-1, e) rather than
append(e).
#header#
<title>Mercurial repositories index</title>
</head>
<body>
<div class="page_header">
<a href="http://www.selenic.com/mercurial/" title="Mercurial"><div style="float:right;">Mercurial</div></a>Repositories list
</div>
<table cellspacing="0">
<tr>
<td><a href="?sort=#sort_name#">Name</a></td>
<td><a href="?sort=#sort_description#">Description</a></td>
<td><a href="?sort=#sort_contact#">Contact</a></td>
<td><a href="?sort=#sort_lastchange#">Last change</a></td>
<td> </td>
<tr>
#entries%indexentry#
</table>
<div class="page_footer">
#motd#
</div>
</body>
</html>