DOMWorkerThreads: Difference between revisions

DOMWorkerThreads (view source)

Revision as of 22:52, 13 August 2008

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@@ Line 1: / Line 1: @@
 == Web Worker API Proposal ==
-== Abstract ==
-This is an API '''proposal''' for DOM Worker Threads.
-At this time this document is not complete.  While we invite discussion on this topic, this is not a stable API proposal, and Mozilla won't implement anything based on it till it becomes stable.
-Look for a post to mozilla.dev.platform when this proposal is ready to be discussed.
-== Introduction ==
-=== Use Cases ===
-=== Terminology ===
-A '''worker''' is an execution context for JavaScript that runs off of the main UI thread. The global scope for a worker is almost empty - familiar objects such as <code>window</code> and <code>document</code> are not available, nor is the Mozilla-specific <code>Components</code> object.
-A '''worker pool''' is a collection of related workers. Workers within a pool can communicate with each other freely, but workers cannot communicate with workers from another pool.
-== Conformance ==
-== Dependencies ==
 == API Proposal ==
@@ Line 45: / Line 23: @@
    readonly attribute boolean closing;
    void close();
+  void postMessage(in DOMString aMessage);
    // event handler attributes
+           attribute EventListener onmessage;
             attribute EventListener onunload;
@@ Line 75: / Line 56: @@
 </code>
 </blockquote>
-=== The worker's scope ===
-The worker's scope is far more limited. See <code>WorkerGlobalScope</code> above for details.
 === Sample usage ===
+Main page:
 <blockquote>
 <code>
 <pre>
-<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
+worker = createWorker("f.js");
-<html>
+worker.onmessage = function(e) {
-  <title>Test threads</title>
+  alert("The 100th Fibonacci number is " + e.data);
-  <body>
+}
-  <script language="javascript">
+worker.postMessage(100);
-    var scriptToRun = 'function messageListener(message, source) { ' +
+</pre>
-                      '  dump("Worker: " + message + "\\n"); ' +
+</code>
-                      '} ' +
+</blockquote>
-                      'for (var i = 0; i < 10000000; i++) { ' +
-                      ' /* do something */ ' +
-                      '} '+
-                      'postMessageToPool("Done!"); ';
-    var wp = navigator.newWorkerPool();
+f.js:
-    wp.messageListener = function(message, source) {
+<blockquote>
-      dump("Pool: " + message + "\n");
+<code>
-    };
+<pre>
-    wp.errorListener = function(error, source) {
+onmessage = function(e) {
-      dump("Pool: error = '" + error + "'\n");
+  if (e.data <= 1)
-    }
+    postMessage(e.data);
-    var threads = []
+  w1 = createWorker("f.js");
-    for (var i = 0; i < 10; i++) {
+  w1.onmessage = handler;
-      var thread = wp.createWorker(scriptToRun);
+  w1.postMessage(e.data - 1);
-      thread.postMessage("hello");
-      threads.push(thread);
+  w2 = createWorker("f.js");
-    }
+  w2.onmessage = handler;
+  w2.postMessage(e.data - 2);
+}
-  </script>
+c = 0;
-  </body>
+sum = 0;
-</html>
+function handler(e) {
+  sum += parseInt(e.data);
+  if (++c == 2) {
+    postMessage(sum);
+  }
+}
 </pre>
 </code>
 </blockquote>
-== Not In This Specification ==
 == References ==
-The only thing I've seen so far is the [http://code.google.com/apis/gears/api_workerpool.html Google Gears WorkerPool API]. We would certainly like to provide a compatibility API that would make migrating Gears code trivial.
+The only thing I've seen so far is the [http://code.google.com/apis/gears/api_workerpool.html Google Gears WorkerPool API]. We would certainly like to provide a API that would make migrating Gears code trivial.
-== Acknowledgements ==