hgweb: use separate repo instances per thread
Before this change, multiple threads/requests could share a
localrepository instance. This meant that all of localrepository needed
to be thread safe. Many bugs have been reported telling us that
localrepository isn't actually thread safe.
While making localrepository thread safe is a noble cause, it is a lot
of work. And there is little gain from doing so. Due to Python's GIL,
only 1 thread may be processing Python code at a time. The benefits
to multi-threaded servers are marginal.
Thread safety would be a lot of work for little gain. So, we're not
going to even attempt it.
This patch establishes a pool of repos in hgweb. When a request arrives,
we obtain the most recently used repository from the pool or create a
new one if none is available. When the request has finished, we put that
repo back in the pool.
We start with a pool size of 1. For servers using a single thread, the
pool will only ever be of size 1. For multi-threaded servers, the pool
size will grow to the max number of simultaneous requests the server
processes.
No logic for pruning the pool has been implemented. We assume server
operators either limit the number of threads to something they can
handle or restart the Mercurial process after a certain amount of
requests or time has passed.
/*
* Styles for man pages, which match with http://mercurial.selenic.com/
*
* Color scheme & layout are borrowed from
* http://mercurial.selenic.com/css/styles.css
*
* Some styles are from html4css1.css from Docutils, which is in the
* public domain.
*/
body {
margin: 0;
padding: 0;
font-family: sans-serif;
}
.document {
position: relative; /* be a top of absolute positioning */
margin: 1.5em 1.8em;
padding: 0;
line-height: 1.3;
}
/* layout: toc to right */
#contents {
position: absolute;
right: 0;
top: 0;
width: 26%;
}
/* layout: others to left */
h1.title, h2.subtitle, .section { width: 72%; }
.section .section { width: auto; }
table.docinfo { max-width: 72%; }
/* headings */
h1, h2, .topic-title, .admonition-title {
font-family: "MgOpen Cosmetica", "Lucida Sans Unicode", sans-serif;
font-weight: normal;
}
h1, h2, .topic-title, .admonition-title {
margin: 1em 0 0.5em;
}
h1.title { font-size: 300%; }
h2.subtitle, h1 { font-size: 200%; }
h2, .topic-title, .admonition-title { font-size: 140%; }
/* subtitle starts with lowercase in man pages, but not in HTML */
h2.subtitle:first-letter { text-transform: uppercase; }
/* override first/last margin */
.first, h1.title, h2.subtitle { margin-top: 0 !important; }
.last, .with-subtitle { margin-bottom: 0 !important; }
blockquote, pre, dd .option-list, .field-list {
margin: 0.2em 0 1em 2em;
}
kbd, tt, pre { font-family: monospace; }
dt { font-weight: bold; }
dd { margin-bottom: 0.5em; }
th, td { padding: 0.1em 0.2em; border: 0 none; }
th { font-weight: bold; text-align: left; }
a:link, a:visited { text-decoration: underline; }
a:hover, a:focus { text-decoration: none; }
a:link { color: #00b5f1; }
a:visited { color: #5c9caf; }
a:link.toc-backref, a:visited.toc-backref {
text-decoration: none;
color: inherit; /* NOTE: `inherit' is not supported by IE6 */
}
div.admonition, div.attention, div.caution,
div.danger, div.error, div.hint, div.important,
div.note, div.tip, div.warning {
border-top: 1px #ccc solid;
border-bottom: 1px #ccc solid;
padding: 0.3em 1em;
margin: 1em;
}
div.note {
border-color: #fcc200;
}
/*
* The following styles are from Docutils.
* Please refine if necessary.
*/
table.borderless td, table.borderless th {
/* Override padding for "table.docutils td" with "! important".
The right padding separates the table cells. */
padding: 0 0.5em 0 0 ! important;
}
.hidden {
display: none;
}
blockquote.epigraph {
margin: 2em 5em;
}
div.abstract {
margin: 2em 5em;
}
div.dedication {
margin: 2em 5em;
text-align: center;
font-style: italic;
}
div.figure {
margin-left: 2em;
margin-right: 2em;
}
div.footer, div.header {
clear: both;
font-size: smaller;
}
div.line-block {
display: block;
margin-top: 1em;
margin-bottom: 1em;
}
div.line-block div.line-block {
margin-top: 0;
margin-bottom: 0;
margin-left: 1.5em;
}
div.sidebar {
margin: 0 0 0.5em 1em;
border: medium outset;
padding: 1em;
background-color: #ffffee;
width: 40%;
float: right;
clear: right;
}
div.sidebar p.rubric {
font-family: sans-serif;
font-size: medium;
}
div.system-messages {
margin: 5em;
}
div.system-messages h1 {
color: red;
}
div.system-message {
border: medium outset;
padding: 1em;
}
div.system-message p.system-message-title {
color: red;
font-weight: bold;
}
h1.section-subtitle, h2.section-subtitle, h3.section-subtitle,
h4.section-subtitle, h5.section-subtitle, h6.section-subtitle {
margin-top: 0.4em;
}
hr.docutils {
width: 75%;
}
img.align-left {
clear: left;
}
img.align-right {
clear: right;
}
ol.simple, ul.simple {
margin-bottom: 1em;
}
ol.arabic {
list-style: decimal;
}
ol.loweralpha {
list-style: lower-alpha;
}
ol.upperalpha {
list-style: upper-alpha;
}
ol.lowerroman {
list-style: lower-roman;
}
ol.upperroman {
list-style: upper-roman;
}
p.attribution {
text-align: right;
margin-left: 50%;
}
p.caption {
font-style: italic;
}
p.credits {
font-style: italic;
font-size: smaller;
}
p.label {
white-space: nowrap;
}
p.rubric {
font-weight: bold;
font-size: larger;
color: maroon;
text-align: center;
}
pre.address {
margin-bottom: 0;
margin-top: 0;
font-family: serif;
font-size: 100%;
}
pre.literal-block, pre.doctest-block {
margin-left: 2em;
margin-right: 2em;
}
span.classifier {
font-family: sans-serif;
font-style: oblique;
}
span.classifier-delimiter {
font-family: sans-serif;
font-weight: bold;
}
span.interpreted {
font-family: sans-serif;
}
span.option {
white-space: nowrap;
}
span.pre {
white-space: pre;
}
span.problematic {
color: red;
}
span.section-subtitle {
/* font-size relative to parent (h1..h6 element) */
font-size: 80%;
}
table.citation {
border-left: solid 1px gray;
margin-left: 1px;
}
table.footnote {
border-left: solid 1px black;
margin-left: 1px;
}
h1 tt.docutils, h2 tt.docutils, h3 tt.docutils,
h4 tt.docutils, h5 tt.docutils, h6 tt.docutils {
font-size: 100%;
}
ul.auto-toc {
list-style-type: none;
}
div.contents.local {
-moz-column-width: 10em;
-moz-column-gap: 1em;
-webkit-column-width: 10em;
-webkit-column-gap: 1em;
}