Backed out changeset 0ca665e88ae5 (bug 1164564) for Linux debug test_promises_actor_onpromisesettled.js failures.

toolkit/devtools/Loader.jsm

@@ -30,6 +30,7 @@ this.EXPORTED_SYMBOLS = ["DevToolsLoader", "devtools", "BuiltinProvider",
 let loaderModules = {
   "Services": Object.create(Services),
   "toolkit/loader": loader,
+  "promise": promise,
   "PromiseDebugging": PromiseDebugging
 };
 XPCOMUtils.defineLazyGetter(loaderModules, "Debugger", () => {
@@ -95,7 +96,6 @@ BuiltinProvider.prototype = {
         "devtools/content-observer": "resource://gre/modules/devtools/content-observer",
         "gcli": "resource://gre/modules/devtools/gcli",
         "projecteditor": "resource:///modules/devtools/projecteditor",
-        "promise": "resource://gre/modules/Promise-backend.js",
         "acorn": "resource://gre/modules/devtools/acorn",
         "acorn/util/walk": "resource://gre/modules/devtools/acorn/walk.js",
         "tern": "resource://gre/modules/devtools/tern",
@@ -135,7 +135,6 @@ SrcdirProvider.prototype = {
     srcdir = OS.Path.normalize(srcdir.data.trim());
     let devtoolsDir = OS.Path.join(srcdir, "browser", "devtools");
     let toolkitDir = OS.Path.join(srcdir, "toolkit", "devtools");
-    let modulesDir = OS.Path.join(srcdir, "toolkit", "modules");
     let mainURI = this.fileURI(OS.Path.join(devtoolsDir, "main.js"));
     let definitionsURI = this.fileURI(OS.Path.join(devtoolsDir, "definitions.js"));
     let devtoolsURI = this.fileURI(devtoolsDir);
@@ -154,7 +153,6 @@ SrcdirProvider.prototype = {
     let contentObserverURI = this.fileURI(OS.Path.join(toolkitDir), "content-observer.js");
     let gcliURI = this.fileURI(OS.Path.join(toolkitDir, "gcli", "source", "lib", "gcli"));
     let projecteditorURI = this.fileURI(OS.Path.join(devtoolsDir, "projecteditor"));
-    let promiseURI = this.fileURI(OS.Path.join(modulesDir, "promise-backend.js"));
     let acornURI = this.fileURI(OS.Path.join(toolkitDir, "acorn"));
     let acornWalkURI = OS.Path.join(acornURI, "walk.js");
     let ternURI = OS.Path.join(toolkitDir, "tern");
@@ -182,7 +180,6 @@ SrcdirProvider.prototype = {
         "devtools/content-observer": contentObserverURI,
         "gcli": gcliURI,
         "projecteditor": projecteditorURI,
-        "promise": promiseURI,
         "acorn": acornURI,
         "acorn/util/walk": acornWalkURI,
         "tern": ternURI,

toolkit/modules/Promise-backend.js

@@ -22,28 +22,9 @@
 ////////////////////////////////////////////////////////////////////////////////
 //// Globals
 
-// Obtain an instance of Cu. How this instance is obtained depends on how this
-// file is loaded.
-//
-// This file can be loaded in three different ways:
-// 1. As a CommonJS module, by Loader.jsm, on the main thread.
-// 2. As a CommonJS module, by worker-loader.js, on a worker thread.
-// 3. As a subscript, by Promise.jsm, on the main thread.
-//
-// If require is defined, the file is loaded as a CommonJS module. Components
-// will not be defined in that case, but we can obtain an instance of Cu from
-// the chrome module. Otherwise, this file is loaded as a subscript, and we can
-// obtain an instance of Cu from Components directly.
-//
-// If the file is loaded as a CommonJS module on a worker thread, the instance
-// of Cu obtained from the chrome module will be null. The reason for this is
-// that Components is not defined in worker threads, so no instance of Cu can
-// be obtained.
-
-let Cu = this.require ? require("chrome").Cu : Components.utils;
-
-// If Cu is defined, use it to lazily define the FinalizationWitnessService.
-if (Cu) {
+// Do not load the FinalizationWitnessService is we are being required as a
+// CommonJS module, because the Components object is not available in workers.
+if (!isWorker) {
   Cu.import("resource://gre/modules/Services.jsm");
   Cu.import("resource://gre/modules/XPCOMUtils.jsm");
 
@@ -65,7 +46,7 @@ const salt = Math.floor(Math.random() * 100);
 const N_INTERNALS = "{private:internals:" + salt + "}";
 
 // We use DOM Promise for scheduling the walker loop.
-const DOMPromise = Cu ? Promise : null;
+const DOMPromise = isWorker ? null : Promise;
 
 /////// Warn-upon-finalization mechanism
 //
@@ -271,9 +252,10 @@ let PendingErrors = {
   }
 };
 
-// Initialize the warn-upon-finalization mechanism if and only if Cu is defined.
-// Otherwise, FinalizationWitnessService won't be defined (see above).
-if (Cu) {
+// Do not initialize the warn-on-finalization mechanism if we are being required
+// as a CommonJS module by the worker loader, because the Components object (and
+// therefore the FinalizationWitnessService) is not available.
+if (!isWorker) {
   PendingErrors.init();
 }
 
@@ -646,9 +628,9 @@ Object.freeze(Promise.Debugging);
 
 Object.freeze(Promise);
 
-// If module is defined, this file is loaded as a CommonJS module. Make sure
-// Promise is exported in that case.
-if (this.module) {
+// Make sure to export the Promise object if we are being required as a CommonJS
+// module by the worker loader.
+if (isWorker) {
   module.exports = Promise;
 }
 
@@ -703,7 +685,7 @@ this.PromiseWalker = {
     aPromise[N_INTERNALS].value = aValue;
     if (aPromise[N_INTERNALS].handlers.length > 0) {
       this.schedulePromise(aPromise);
-    } else if (Cu && aStatus == STATUS_REJECTED) {
+    } else if (!isWorker && aStatus == STATUS_REJECTED) {
       // This is a rejection and the promise is the last in the chain.
       // For the time being we therefore have an uncaught error.
       let id = PendingErrors.register(aValue);
@@ -719,25 +701,10 @@ this.PromiseWalker = {
   scheduleWalkerLoop: function()
   {
     this.walkerLoopScheduled = true;
-
-    // If this file is loaded on a worker thread, DOMPromise will not behave as
-    // expected: because native promises are not aware of nested event loops
-    // created by the debugger, their respective handlers will not be called
-    // until after leaving the nested event loop. The debugger server relies
-    // heavily on the use promises, so this could cause the debugger to hang.
-    //
-    // To work around this problem, any use of native promises in the debugger
-    // server should be avoided when it is running on a worker thread. Because
-    // it is still necessary to be able to schedule runnables on the event
-    // queue, the worker loader defines the function setImmediate as a
-    // per-module global for this purpose.
-    //
-    // If Cu is defined, this file is loaded on the main thread. Otherwise, it
-    // is loaded on the worker thread.
-    if (Cu) {
-      DOMPromise.resolve().then(() => this.walkerLoop());
-    } else {
+    if (isWorker) {
       setImmediate(this.walkerLoop);
+    } else {
+      DOMPromise.resolve().then(() => this.walkerLoop());
     }
   },
 

toolkit/modules/Promise.jsm

@@ -96,6 +96,17 @@ this.Ci = Components.interfaces;
 this.Cu = Components.utils;
 this.Cr = Components.results;
 
+// Promise-backend.js can either be loaded as a subscript by this file, or
+// required as a CommonJS module by the worker loader. Because certain APIS (in
+// particular, Components) are not available in workers, Promise-backend.js
+// behaves slightly different in the latter case.
+//
+// To distinguish between these two cases, the worker loader defines a global
+// variable isWorker, and sets it to true. When loading Promise-backend.js as
+// a subscript, we need to make sure this variable is defined as well, and set
+// it to false.
+this.isWorker = false;
+
 this.Cc["@mozilla.org/moz/jssubscript-loader;1"]
     .getService(this.Ci.mozIJSSubScriptLoader)
     .loadSubScript("resource://gre/modules/Promise-backend.js", this);