Mercurial > my-ubiquity-commands

comparison pseudo-weak-refs/index.html @ 18:08bddf757ed8

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
Added pseudo-weak-refs feed.
author Atul Varma <varmaa@toolness.com>
date Sat, 25 Apr 2009 13:38:25 -0700
parents
children
comparison
equal deleted inserted replaced
17:f3e03596fcf9 18:08bddf757ed8
1 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
2 "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
3 <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
4 <head>
5 <meta http-equiv="Content-type" content="text/html; charset=utf-8" />
6 <link rel="stylesheet" type="text/css" media="all"
7 href="index.css" />
8 <link rel="commands" href="pseudo-weak-refs.js"/>
9 <title>Pseudo Weak References for Web Content</title>
10 </head>
11 <body>
12 <div id="container">
13 <div id="content">
14 <h1>Pseudo Weak References for Web Content</h1>
15 <p>This Ubiquity feed provides pseudo weak reference functionality to
16 web content, for the purpose of making it easier to debug memory
17 management issues. Specifically, it adds two new functions to
18 the global <tt>window</tt> object of all web pages:</p>
19 <ul>
20 <li><tt>PseudoWeakRef(object)</tt> is a constructor that makes a
21 pseudo-weak reference for the object. The returned object has one
22 method, <tt>exists()</tt>, which returns whether or not the
23 referent still exists.</li>
24 <li><tt>forceGC()</tt> forces garbage collection.</li>
25 </ul>
26 <p>Here's some example code:</p>
27 <script id="tests">
28 function testExistsReturnsFalse() {
29 var object = new Object();
30 var weak = new PseudoWeakRef(object);
31
32 // Destroy our one strong reference to the object, leaving it available
33 // for garbage collection.
34 object = null;
35
36 forceGC();
37 if (weak.exists())
38 throw new Error("weak referent should not exist");
39 }
40 </script>
41 <p>The above source code is actually part of the test suite for this
42 feed. <span id="test-result">If this feed were installed, the suite would
43 run now.</span></p>
44 <p>The source code for this feed can be viewed
45 at <a href="pseudo-weak-refs.js">pseudo-weak-refs.js</a>.</p>
46 </div>
47 <div id="messages">
48 <span id="tests-failed">The suite was run, but some tests failed.</span>
49 <span id="tests-passed">The suite was run, and all tests passed.</span>
50 </div>
51 </div>
52 <script>
53 function testExistsReturnsTrue() {
54 var object = new Object();
55 var weak = new PseudoWeakRef(object);
56 forceGC();
57 if (!weak.exists())
58 throw new Error("weak referent should exist");
59 }
60
61 function onLoad() {
62 function $(id) { return document.getElementById(id); }
63
64 $("tests").innerHTML = $("tests").innerHTML.slice(1);
65 if (window.PseudoWeakRef && window.forceGC) {
66 try {
67 testExistsReturnsFalse();
68 testExistsReturnsTrue();
69 } catch (e) {
70 $("test-result").innerHTML = $("tests-failed").innerHTML;
71 throw e;
72 }
73 $("test-result").innerHTML = $("tests-passed").innerHTML;
74 }
75 }
76
77 window.addEventListener("load", onLoad, false);
78 </script>
79 </body>
80 </html>