encoding: fix trim() to be O(n) instead of O(n^2)
`encoding.trim()` iterated over the possible lengths smaller than the
input and created a slice for each. It then calculated the column
width of the result, which is of course O(n), so the overall algorithm
was O(n). This patch rewrites it to iterate over the unicode
characters, keeping track of the length so far. Also, the old
algorithm started from the end of the string, which made it much worse
when the input is large and the limit is small (such as the typical 72
we pass to it).
You can time it by running something like this:
```
time python3 -c 'from mercurial.utils import stringutil; print(stringutil.ellipsis(b"0123456789" * 1000, 5))'
```
That drops from 4.05 s to 83 ms with this patch (and most of that is
of course startup time).
Differential Revision: https://phab.mercurial-scm.org/D12089
#require serve
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
$ (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="https://mercurial-scm.org/">
<img src="/static/hglogo.png" alt="mercurial" /></a>
</div>
<ul>
<li class="active">log</li>
<li><a href="/graph/tip">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/tip">changeset</a></li>
<li><a href="/file/tip">browse</a></li>
</ul>
<ul>
</ul>
<ul>
<li><a href="/help">help</a></li>
</ul>
<div class="atom-logo">
<a href="/atom-log" title="subscribe to atom feed">
<img class="atom-logo" src="/static/feed-icon-14x14.png" alt="atom feed" />
</a>
</div>
</div>
<div class="main">
<h2 class="breadcrumb"><a href="/">Mercurial</a> </h2>
<h3>log</h3>
<form class="search" action="/log">
<p><input name="rev" id="search1" type="text" size="30" value="" /></p>
<div id="hint">Find changesets by keywords (author, files, the commit message), revision
number or hash, or <a href="/help/revsets">revset expression</a>.</div>
</form>
<div class="navigate">
<a href="/shortlog/tip?revcount=30">less</a>
<a href="/shortlog/tip?revcount=120">more</a>
| rev -1:
</div>
<table class="bigtable">
<thead>
<tr>
<th class="age">age</th>
<th class="author">author</th>
<th class="description">description</th>
</tr>
</thead>
<tbody class="stripes2">
</tbody>
</table>
<div class="navigate">
<a href="/shortlog/tip?revcount=30">less</a>
<a href="/shortlog/tip?revcount=120">more</a>
| rev -1:
</div>
<script type="text/javascript">
ajaxScrollInit(
'/shortlog/%next%',
'', <!-- NEXTHASH
function (htmlText) {
var m = htmlText.match(/'(\w+)', <!-- NEXTHASH/);
return m ? m[1] : null;
},
'.bigtable > tbody',
'<tr class="%class%">\
<td colspan="3" style="text-align: center;">%text%</td>\
</tr>'
);
</script>
</div>
</div>
</body>
</html>
$ echo babar
babar
$ (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="https://mercurial-scm.org/">
<img src="/static/hglogo.png" alt="mercurial" /></a>
</div>
<ul>
<li class="active">log</li>
<li><a href="/graph/tip">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/tip">changeset</a></li>
<li><a href="/file/tip">browse</a></li>
</ul>
<ul>
</ul>
<ul>
<li><a href="/help">help</a></li>
</ul>
<div class="atom-logo">
<a href="/atom-log" title="subscribe to atom feed">
<img class="atom-logo" src="/static/feed-icon-14x14.png" alt="atom feed" />
</a>
</div>
</div>
<div class="main">
<h2 class="breadcrumb"><a href="/">Mercurial</a> </h2>
<h3>log</h3>
<form class="search" action="/log">
<p><input name="rev" id="search1" type="text" size="30" value="" /></p>
<div id="hint">Find changesets by keywords (author, files, the commit message), revision
number or hash, or <a href="/help/revsets">revset expression</a>.</div>
</form>
<div class="navigate">
<a href="/shortlog/tip?revcount=5">less</a>
<a href="/shortlog/tip?revcount=20">more</a>
| rev -1:
</div>
<table class="bigtable">
<thead>
<tr>
<th class="age">age</th>
<th class="author">author</th>
<th class="description">description</th>
</tr>
</thead>
<tbody class="stripes2">
</tbody>
</table>
<div class="navigate">
<a href="/shortlog/tip?revcount=5">less</a>
<a href="/shortlog/tip?revcount=20">more</a>
| rev -1:
</div>
<script type="text/javascript">
ajaxScrollInit(
'/shortlog/%next%',
'', <!-- NEXTHASH
function (htmlText) {
var m = htmlText.match(/'(\w+)', <!-- NEXTHASH/);
return m ? m[1] : null;
},
'.bigtable > tbody',
'<tr class="%class%">\
<td colspan="3" style="text-align: center;">%text%</td>\
</tr>'
);
</script>
</div>
</div>
</body>
</html>
$ (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" />
</head>
<body>
<div class="container">
<div class="menu">
<div class="logo">
<a href="https://mercurial-scm.org/">
<img src="/static/hglogo.png" alt="mercurial" /></a>
</div>
<ul>
<li><a href="/shortlog/tip">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/tip">changeset</a></li>
<li><a href="/file/tip">browse</a></li>
</ul>
<ul>
</ul>
<ul>
<li><a href="/help">help</a></li>
</ul>
<div class="atom-logo">
<a href="/atom-log" title="subscribe to atom feed">
<img class="atom-logo" src="/static/feed-icon-14x14.png" alt="atom feed" />
</a>
</div>
</div>
<div class="main">
<h2 class="breadcrumb"><a href="/">Mercurial</a> </h2>
<h3>graph</h3>
<form class="search" action="/log">
<p><input name="rev" id="search1" type="text" size="30" value="" /></p>
<div id="hint">Find changesets by keywords (author, files, the commit message), revision
number or hash, or <a href="/help/revsets">revset expression</a>.</div>
</form>
<div class="navigate">
<a href="/graph/tip?revcount=30">less</a>
<a href="/graph/tip?revcount=120">more</a>
| rev -1:
</div>
<noscript><p>The revision graph only works with JavaScript-enabled browsers.</p></noscript>
<div id="wrapper">
<canvas id="graph"></canvas>
<ul id="graphnodes" class="stripes2"></ul>
</div>
<script type="text/javascript">
var data = [];
var graph = new Graph();
graph.scale(39);
graph.render(data);
</script>
<div class="navigate">
<a href="/graph/tip?revcount=30">less</a>
<a href="/graph/tip?revcount=120">more</a>
| rev -1:
</div>
<script type="text/javascript">
ajaxScrollInit(
'/graph/%next%?graphtop=0000000000000000000000000000000000000000',
'', <!-- NEXTHASH
function (htmlText) {
var m = htmlText.match(/'(\w+)', <!-- NEXTHASH/);
return m ? m[1] : null;
},
'#wrapper',
'<div class="%class%" style="text-align: center;">%text%</div>',
'graph'
);
</script>
</div>
</div>
</body>
</html>
$ (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="https://mercurial-scm.org/">
<img src="/static/hglogo.png" alt="mercurial" /></a>
</div>
<ul>
<li><a href="/shortlog/tip">log</a></li>
<li><a href="/graph/tip">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/tip">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 class="breadcrumb"><a href="/">Mercurial</a> </h2>
<h3>
directory / @ -1:<a href="/rev/000000000000">000000000000</a>
<span class="tag">tip</span>
</h3>
<form class="search" action="/log">
<p><input name="rev" id="search1" type="text" size="30" value="" /></p>
<div id="hint">Find changesets by keywords (author, files, the commit message), revision
number or hash, or <a href="/help/revsets">revset expression</a>.</div>
</form>
<table class="bigtable">
<thead>
<tr>
<th class="name">name</th>
<th class="size">size</th>
<th class="permissions">permissions</th>
</tr>
</thead>
<tbody class="stripes2">
</tbody>
</table>
</div>
</div>
</body>
</html>
$ (get-with-headers.py localhost:$HGPORT 'atom-bookmarks')
200 Script output follows
<?xml version="1.0" encoding="ascii"?>
<feed xmlns="http://www.w3.org/2005/Atom">
<id>http://*:$HGPORT/</id> (glob)
<link rel="self" href="http://*:$HGPORT/atom-bookmarks"/> (glob)
<link rel="alternate" href="http://*:$HGPORT/bookmarks"/> (glob)
<title>test: bookmarks</title>
<summary>test bookmark history</summary>
<author><name>Mercurial SCM</name></author>
<updated>1970-01-01T00:00:00+00:00</updated>
</feed>
$ cd ..