Bug 1225477 - Support listening for processes creation. r=jryans

devtools/server/actors/moz.build

@@ -40,6 +40,7 @@ DevToolsModules(
     'performance.js',
     'preference.js',
     'pretty-print-worker.js',
+    'process.js',
     'profiler.js',
     'promises.js',
     'root.js',

devtools/server/actors/process.js

@@ -0,0 +1,83 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+
+var { Cc, Ci } = require("chrome");
+
+loader.lazyGetter(this, "ppmm", () => {
+  return Cc["@mozilla.org/parentprocessmessagemanager;1"].getService(Ci.nsIMessageBroadcaster);
+});
+
+function ProcessActorList() {
+  this._actors = new Map();
+  this._onListChanged = null;
+  this._mustNotify = false;
+
+  this._onMessage = this._onMessage.bind(this);
+  this._processScript = "data:text/javascript,sendAsyncMessage('debug:new-process');";
+}
+
+ProcessActorList.prototype = {
+  getList: function () {
+    let processes = [];
+    for (let i = 0; i < ppmm.childCount; i++) {
+      processes.push({
+        id: i, // XXX: may not be a perfect id, but process message manager doesn't expose anything...
+        parent: i == 0, // XXX Weak, but appear to be stable
+        tabCount: undefined, // TODO: exposes process message manager on frameloaders in order to compute this
+      });
+    }
+    this._mustNotify = true;
+    this._checkListening();
+
+    return processes;
+  },
+
+  get onListChanged() {
+    return this._onListChanged;
+  },
+
+  set onListChanged(onListChanged) {
+    if (typeof onListChanged !== "function" && onListChanged !== null) {
+      throw new Error("onListChanged must be either a function or null.");
+    }
+    if (onListChanged === this._onListChanged) {
+      return;
+    }
+
+    this._onListChanged = onListChanged;
+    this._checkListening();
+  },
+
+  _checkListening: function () {
+    if (this._onListChanged !== null && this._mustNotify) {
+      this._knownProcesses = [];
+      for (let i = 0; i < ppmm.childCount; i++) {
+        this._knownProcesses.push(ppmm.getChildAt(i));
+      }
+      ppmm.addMessageListener('debug:new-process', this._onMessage);
+      ppmm.loadProcessScript(this._processScript, true);
+    } else {
+      ppmm.removeMessageListener('debug:new-process', this._onMessage);
+      ppmm.removeDelayedProcessScript(this._processScript);
+    }
+  },
+
+  _notifyListChanged: function () {
+    if (this._mustNotify) {
+      this._onListChanged();
+      this._mustNotify = false;
+    }
+  },
+
+  _onMessage: function ({ target }) {
+    if (this._knownProcesses.includes(target)) {
+      return;
+    }
+    this._notifyListChanged();
+  },
+};
+
+exports.ProcessActorList = ProcessActorList;

devtools/server/actors/root.js

@@ -96,6 +96,7 @@ function RootActor(aConnection, aParameters) {
   this._onAddonListChanged = this.onAddonListChanged.bind(this);
   this._onWorkerListChanged = this.onWorkerListChanged.bind(this);
   this._onServiceWorkerRegistrationListChanged = this.onServiceWorkerRegistrationListChanged.bind(this);
+  this._onProcessListChanged = this.onProcessListChanged.bind(this);
   this._extraActors = {};
 
   this._globalActorPool = new ActorPool(this.conn);
@@ -419,15 +420,20 @@ RootActor.prototype = {
   },
 
   onListProcesses: function () {
-    let processes = [];
-    for (let i = 0; i < ppmm.childCount; i++) {
-      processes.push({
-        id: i, // XXX: may not be a perfect id, but process message manager doesn't expose anything...
-        parent: i == 0, // XXX Weak, but appear to be stable
-        tabCount: undefined, // TODO: exposes process message manager on frameloaders in order to compute this
-      });
+    let { processList } = this._parameters;
+    if (!processList) {
+      return { from: this.actorID, error: "noProcesses",
+               message: "This root actor has no processes." };
     }
-    return { processes: processes };
+    processList.onListChanged = this._onProcessListChanged;
+    return {
+      processes: processList.getList()
+    };
+  },
+
+  onProcessListChanged: function () {
+    this.conn.send({ from: this.actorID, type: "processListChanged" });
+    this._parameters.processList.onListChanged = null;
   },
 
   onGetProcess: function (aRequest) {

devtools/server/actors/webbrowser.js

@@ -24,6 +24,7 @@ loader.lazyRequireGetter(this, "unwrapDebuggerObjectGlobal", "devtools/server/ac
 loader.lazyRequireGetter(this, "BrowserAddonActor", "devtools/server/actors/addon", true);
 loader.lazyRequireGetter(this, "WorkerActorList", "devtools/server/actors/worker", true);
 loader.lazyRequireGetter(this, "ServiceWorkerRegistrationActorList", "devtools/server/actors/worker", true);
+loader.lazyRequireGetter(this, "ProcessActorList", "devtools/server/actors/process", true);
 loader.lazyImporter(this, "AddonManager", "resource://gre/modules/AddonManager.jsm");
 
 // Assumptions on events module:
@@ -132,6 +133,7 @@ function createRootActor(aConnection)
                          addonList: new BrowserAddonList(aConnection),
                          workerList: new WorkerActorList({}),
                          serviceWorkerRegistrationList: new ServiceWorkerRegistrationActorList(),
+                         processList: new ProcessActorList(),
                          globalActorFactories: DebuggerServer.globalActorFactories,
                          onShutdown: sendShutdownEvent
                        });

devtools/server/tests/mochitest/test_getProcess.html

@@ -28,21 +28,15 @@ window.onload = function() {
     "set": [
       // Always log packets when running tests.
       ["devtools.debugger.log", true],
-      ["dom.mozBrowserFramesEnabled", true]
+      // Enabled mozbrowser frame to support remote=true
+      ["dom.mozBrowserFramesEnabled", true],
+      // Allows creating a branch new process when creation the iframe
+      ["dom.ipc.processCount", 10],
     ]
   }, runTests);
 }
 
 function runTests() {
-  // Create a remote iframe with a message manager
-  let iframe = document.createElement("iframe");
-  iframe.mozbrowser = true;
-  iframe.setAttribute("remote", "true");
-  iframe.setAttribute("src", "data:text/html,foo");
-  document.body.appendChild(iframe);
-
-  let mm = iframe.QueryInterface(Ci.nsIFrameLoaderOwner).frameLoader.messageManager;
-
   // Instantiate a minimal server
   if (!DebuggerServer.initialized) {
     DebuggerServer.init();
@@ -52,13 +46,41 @@ function runTests() {
     DebuggerServer.addBrowserActors();
   }
 
-  function firstClient() {
+  let client, iframe, processCount;
+
+  function connect() {
     // Fake a first connection to the content process
     let transport = DebuggerServer.connectPipe();
-    let client = new DebuggerClient(transport);
-    client.connect(() => {
+    client = new DebuggerClient(transport);
+    client.connect(listProcess);
+  }
+
+  function listProcess() {
+    // Call listProcesses in order to start receiving new process notifications
+    client.addListener("processListChanged", function listener() {
+      client.removeListener("processListChanged", listener);
+      ok(true, "Received processListChanged event");
+      getProcess();
+    });
+    client.mainRoot.listProcesses(response => {
+      processCount = response.processes.length;
+      // Create a remote iframe to spawn a new process
+      createRemoteIframe();
+    });
+  }
+
+  function createRemoteIframe() {
+    iframe = document.createElement("iframe");
+    iframe.mozbrowser = true;
+    iframe.setAttribute("remote", "true");
+    iframe.setAttribute("src", "data:text/html,foo");
+    document.body.appendChild(iframe);
+  }
+
+  function getProcess() {
     client.mainRoot.listProcesses(response => {
       ok(response.processes.length >= 2, "Got at least the parent process and one child");
+      is(response.processes.length, processCount+1 , "Got one additional process on the second call to listProcesses");
 
       // Connect to the first content processe available
       let content = response.processes.filter(p => (!p.parent))[0];
@@ -75,21 +97,21 @@ function runTests() {
           text: "var a = 42; a"
         }, function (response) {
           ok(response.result, 42, "console.eval worked");
-
-          client.close(cleanup);
+          cleanup();
         });
       });
     });
-    });
   }
 
   function cleanup() {
-    DebuggerServer.destroy();
-    iframe.remove();
-    SimpleTest.finish()
+    client.close(function () {
+      DebuggerServer.destroy();
+      iframe.remove();
+      SimpleTest.finish()
+    });
   }
 
-  firstClient();
+  connect();
 }
 
 </script>