revlog: improve delta generation heuristics for generaldelta
Without this change, pulls (and clones) into a generaldelta repository could
generate very inefficient revlogs, the size of which could be at least twice
the original size.
This was caused by the generated delta chains covering too large distances,
causing new chains to be built far too often. This change addresses the
problem by forcing a delta against second parent or against the previous
revision, when the first parent delta is in danger of creating a long chain.
Some tests for hgweb in an empty repository
$ hg init test
$ cd test
$ hg serve -n test -p $HGPORT -d --pid-file=hg.pid -A access.log -E errors.log
$ cat hg.pid >> $DAEMON_PIDS
$ ("$TESTDIR/get-with-headers.py" localhost:$HGPORT '/shortlog')
200 Script output follows
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en-US">
<head>
<link rel="icon" href="/static/hgicon.png" type="image/png" />
<meta name="robots" content="index, nofollow" />
<link rel="stylesheet" href="/static/style-paper.css" type="text/css" />
<script type="text/javascript" src="/static/mercurial.js"></script>
<title>test: log</title>
<link rel="alternate" type="application/atom+xml"
href="/atom-log" title="Atom feed for test" />
<link rel="alternate" type="application/rss+xml"
href="/rss-log" title="RSS feed for test" />
</head>
<body>
<div class="container">
<div class="menu">
<div class="logo">
<a href="http://mercurial.selenic.com/">
<img src="/static/hglogo.png" alt="mercurial" /></a>
</div>
<ul>
<li class="active">log</li>
<li><a href="/graph/000000000000">graph</a></li>
<li><a href="/tags">tags</a></li>
<li><a href="/bookmarks">bookmarks</a></li>
<li><a href="/branches">branches</a></li>
</ul>
<ul>
<li><a href="/rev/000000000000">changeset</a></li>
<li><a href="/file/000000000000">browse</a></li>
</ul>
<ul>
</ul>
<ul>
<li><a href="/help">help</a></li>
</ul>
</div>
<div class="main">
<h2><a href="/">test</a></h2>
<h3>log</h3>
<form class="search" action="/log">
<p><input name="rev" id="search1" type="text" size="30" /></p>
<div id="hint">find changesets by author, revision,
files, or words in the commit message</div>
</form>
<div class="navigate">
<a href="/shortlog/-1?revcount=30">less</a>
<a href="/shortlog/-1?revcount=120">more</a>
| rev -1: <a href="/shortlog/000000000000">(0)</a> <a href="/shortlog/tip">tip</a>
</div>
<table class="bigtable">
<tr>
<th class="age">age</th>
<th class="author">author</th>
<th class="description">description</th>
</tr>
</table>
<div class="navigate">
<a href="/shortlog/-1?revcount=30">less</a>
<a href="/shortlog/-1?revcount=120">more</a>
| rev -1: <a href="/shortlog/000000000000">(0)</a> <a href="/shortlog/tip">tip</a>
</div>
</div>
</div>
<script type="text/javascript">process_dates()</script>
</body>
</html>
$ ("$TESTDIR/get-with-headers.py" localhost:$HGPORT '/log')
200 Script output follows
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en-US">
<head>
<link rel="icon" href="/static/hgicon.png" type="image/png" />
<meta name="robots" content="index, nofollow" />
<link rel="stylesheet" href="/static/style-paper.css" type="text/css" />
<script type="text/javascript" src="/static/mercurial.js"></script>
<title>test: log</title>
<link rel="alternate" type="application/atom+xml"
href="/atom-log" title="Atom feed for test" />
<link rel="alternate" type="application/rss+xml"
href="/rss-log" title="RSS feed for test" />
</head>
<body>
<div class="container">
<div class="menu">
<div class="logo">
<a href="http://mercurial.selenic.com/">
<img src="/static/hglogo.png" alt="mercurial" /></a>
</div>
<ul>
<li class="active">log</li>
<li><a href="/graph/000000000000">graph</a></li>
<li><a href="/tags">tags</a></li>
<li><a href="/bookmarks">bookmarks</a></li>
<li><a href="/branches">branches</a></li>
</ul>
<ul>
<li><a href="/rev/000000000000">changeset</a></li>
<li><a href="/file/000000000000">browse</a></li>
</ul>
<ul>
</ul>
<ul>
<li><a href="/help">help</a></li>
</ul>
</div>
<div class="main">
<h2><a href="/">test</a></h2>
<h3>log</h3>
<form class="search" action="/log">
<p><input name="rev" id="search1" type="text" size="30" /></p>
<div id="hint">find changesets by author, revision,
files, or words in the commit message</div>
</form>
<div class="navigate">
<a href="/shortlog/-1?revcount=5">less</a>
<a href="/shortlog/-1?revcount=20">more</a>
| rev -1: <a href="/shortlog/000000000000">(0)</a> <a href="/shortlog/tip">tip</a>
</div>
<table class="bigtable">
<tr>
<th class="age">age</th>
<th class="author">author</th>
<th class="description">description</th>
</tr>
</table>
<div class="navigate">
<a href="/shortlog/-1?revcount=5">less</a>
<a href="/shortlog/-1?revcount=20">more</a>
| rev -1: <a href="/shortlog/000000000000">(0)</a> <a href="/shortlog/tip">tip</a>
</div>
</div>
</div>
<script type="text/javascript">process_dates()</script>
</body>
</html>
$ ("$TESTDIR/get-with-headers.py" localhost:$HGPORT '/graph')
200 Script output follows
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en-US">
<head>
<link rel="icon" href="/static/hgicon.png" type="image/png" />
<meta name="robots" content="index, nofollow" />
<link rel="stylesheet" href="/static/style-paper.css" type="text/css" />
<script type="text/javascript" src="/static/mercurial.js"></script>
<title>test: revision graph</title>
<link rel="alternate" type="application/atom+xml"
href="/atom-log" title="Atom feed for test: log" />
<link rel="alternate" type="application/rss+xml"
href="/rss-log" title="RSS feed for test: log" />
<!--[if IE]><script type="text/javascript" src="/static/excanvas.js"></script><![endif]-->
</head>
<body>
<div class="container">
<div class="menu">
<div class="logo">
<a href="http://mercurial.selenic.com/">
<img src="/static/hglogo.png" alt="mercurial" /></a>
</div>
<ul>
<li><a href="/shortlog/000000000000">log</a></li>
<li class="active">graph</li>
<li><a href="/tags">tags</a></li>
<li><a href="/bookmarks">bookmarks</a></li>
<li><a href="/branches">branches</a></li>
</ul>
<ul>
<li><a href="/rev/000000000000">changeset</a></li>
<li><a href="/file/000000000000">browse</a></li>
</ul>
<ul>
<li><a href="/help">help</a></li>
</ul>
</div>
<div class="main">
<h2><a href="/">test</a></h2>
<h3>graph</h3>
<form class="search" action="/log">
<p><input name="rev" id="search1" type="text" size="30" /></p>
<div id="hint">find changesets by author, revision,
files, or words in the commit message</div>
</form>
<div class="navigate">
<a href="/graph/-1?revcount=30">less</a>
<a href="/graph/-1?revcount=120">more</a>
| rev -1: <a href="/graph/000000000000">(0)</a> <a href="/graph/tip">tip</a>
</div>
<noscript><p>The revision graph only works with JavaScript-enabled browsers.</p></noscript>
<div id="wrapper">
<ul id="nodebgs"></ul>
<canvas id="graph" width="480" height="12"></canvas>
<ul id="graphnodes"></ul>
</div>
<script type="text/javascript">
<!-- hide script content
var data = [];
var graph = new Graph();
graph.scale(39);
graph.edge = function(x0, y0, x1, y1, color) {
this.setColor(color, 0.0, 0.65);
this.ctx.beginPath();
this.ctx.moveTo(x0, y0);
this.ctx.lineTo(x1, y1);
this.ctx.stroke();
}
var revlink = '<li style="_STYLE"><span class="desc">';
revlink += '<a href="/rev/_NODEID" title="_NODEID">_DESC</a>';
revlink += '</span>_TAGS<span class="info">_DATE, by _USER</span></li>';
graph.vertex = function(x, y, color, parity, cur) {
this.ctx.beginPath();
color = this.setColor(color, 0.25, 0.75);
this.ctx.arc(x, y, radius, 0, Math.PI * 2, true);
this.ctx.fill();
var bg = '<li class="bg parity' + parity + '"></li>';
var left = (this.columns + 1) * this.bg_height;
var nstyle = 'padding-left: ' + left + 'px;';
var item = revlink.replace(/_STYLE/, nstyle);
item = item.replace(/_PARITY/, 'parity' + parity);
item = item.replace(/_NODEID/, cur[0]);
item = item.replace(/_NODEID/, cur[0]);
item = item.replace(/_DESC/, cur[3]);
item = item.replace(/_USER/, cur[4]);
item = item.replace(/_DATE/, cur[5]);
var tagspan = '';
if (cur[7].length || (cur[6][0] != 'default' || cur[6][1])) {
tagspan = '<span class="logtags">';
if (cur[6][1]) {
tagspan += '<span class="branchhead" title="' + cur[6][0] + '">';
tagspan += cur[6][0] + '</span> ';
} else if (!cur[6][1] && cur[6][0] != 'default') {
tagspan += '<span class="branchname" title="' + cur[6][0] + '">';
tagspan += cur[6][0] + '</span> ';
}
if (cur[7].length) {
for (var t in cur[7]) {
var tag = cur[7][t];
tagspan += '<span class="tag">' + tag + '</span> ';
}
}
if (cur[8].length) {
for (var b in cur[8]) {
var bookmark = cur[8][b];
tagspan += '<span class="tag">' + bookmark + '</span> ';
}
}
tagspan += '</span>';
}
item = item.replace(/_TAGS/, tagspan);
return [bg, item];
}
graph.render(data);
// stop hiding script -->
</script>
<div class="navigate">
<a href="/graph/-1?revcount=30">less</a>
<a href="/graph/-1?revcount=120">more</a>
| rev -1: <a href="/graph/000000000000">(0)</a> <a href="/graph/tip">tip</a>
</div>
</div>
</div>
<script type="text/javascript">process_dates()</script>
</body>
</html>
$ ("$TESTDIR/get-with-headers.py" localhost:$HGPORT '/file')
200 Script output follows
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en-US">
<head>
<link rel="icon" href="/static/hgicon.png" type="image/png" />
<meta name="robots" content="index, nofollow" />
<link rel="stylesheet" href="/static/style-paper.css" type="text/css" />
<script type="text/javascript" src="/static/mercurial.js"></script>
<title>test: 000000000000 /</title>
</head>
<body>
<div class="container">
<div class="menu">
<div class="logo">
<a href="http://mercurial.selenic.com/">
<img src="/static/hglogo.png" alt="mercurial" /></a>
</div>
<ul>
<li><a href="/shortlog/000000000000">log</a></li>
<li><a href="/graph/000000000000">graph</a></li>
<li><a href="/tags">tags</a></li>
<li><a href="/bookmarks">bookmarks</a></li>
<li><a href="/branches">branches</a></li>
</ul>
<ul>
<li><a href="/rev/000000000000">changeset</a></li>
<li class="active">browse</li>
</ul>
<ul>
</ul>
<ul>
<li><a href="/help">help</a></li>
</ul>
</div>
<div class="main">
<h2><a href="/">test</a></h2>
<h3>directory / @ -1:000000000000 <span class="tag">tip</span> </h3>
<form class="search" action="/log">
<p><input name="rev" id="search1" type="text" size="30" /></p>
<div id="hint">find changesets by author, revision,
files, or words in the commit message</div>
</form>
<table class="bigtable">
<tr>
<th class="name">name</th>
<th class="size">size</th>
<th class="permissions">permissions</th>
</tr>
<tr class="fileline parity0">
<td class="name"><a href="/file/000000000000/">[up]</a></td>
<td class="size"></td>
<td class="permissions">drwxr-xr-x</td>
</tr>
</table>
</div>
</div>
<script type="text/javascript">process_dates()</script>
</body>
</html>