Bug 1125817 - Fix async/sync consistencies with web audio tool client node events. r=vp

browser/devtools/webaudioeditor/controller.js

@@ -93,32 +93,24 @@ let WebAudioEditorController = {
     PropertiesView.resetUI();
   },
 
-  // Since node create and connect are probably executed back to back,
-  // and the controller's `_onCreateNode` needs to look up type,
-  // the edge creation could be called before the graph node is actually
-  // created. This way, we can check and listen for the event before
-  // adding an edge.
-  _waitForNodeCreation: function (sourceActor, destActor) {
-    let deferred = defer();
-    let source = gAudioNodes.get(sourceActor.actorID);
-    let dest = gAudioNodes.get(destActor.actorID);
+  // Since node events (create, disconnect, connect) are all async,
+  // we have to make sure to wait that the node has finished creating
+  // before performing an operation on it.
+  getNode: function* (nodeActor) {
+    let id = nodeActor.actorID;
+    let node = gAudioNodes.get(id);
 
-    if (!source || !dest) {
+    if (!node) {
+      let { resolve, promise } = defer();
       gAudioNodes.on("add", function createNodeListener (createdNode) {
-        if (sourceActor.actorID === createdNode.id)
-          source = createdNode;
-        if (destActor.actorID === createdNode.id)
-          dest = createdNode;
-        if (source && dest) {
+        if (createdNode.id === id) {
           gAudioNodes.off("add", createNodeListener);
-          deferred.resolve([source, dest]);
+          resolve(createdNode);
         }
       });
+      node = yield promise;
     }
-    else {
-      deferred.resolve([source, dest]);
-    }
-    return deferred.promise;
+    return node;
   },
 
   /**
@@ -202,7 +194,8 @@ let WebAudioEditorController = {
    * Called when a node is connected to another node.
    */
   _onConnectNode: Task.async(function* ({ source: sourceActor, dest: destActor }) {
-    let [source, dest] = yield WebAudioEditorController._waitForNodeCreation(sourceActor, destActor);
+    let source = yield WebAudioEditorController.getNode(sourceActor);
+    let dest = yield WebAudioEditorController.getNode(destActor);
     source.connect(dest);
   }),
 
@@ -210,22 +203,24 @@ let WebAudioEditorController = {
    * Called when a node is conneceted to another node's AudioParam.
    */
   _onConnectParam: Task.async(function* ({ source: sourceActor, dest: destActor, param }) {
-    let [source, dest] = yield WebAudioEditorController._waitForNodeCreation(sourceActor, destActor);
+    let source = yield WebAudioEditorController.getNode(sourceActor);
+    let dest = yield WebAudioEditorController.getNode(destActor);
     source.connect(dest, param);
   }),
 
   /**
    * Called when a node is disconnected.
    */
-  _onDisconnectNode: function(nodeActor) {
-    let node = gAudioNodes.get(nodeActor.actorID);
+  _onDisconnectNode: Task.async(function* (nodeActor) {
+    let node = yield WebAudioEditorController.getNode(nodeActor);
     node.disconnect();
-  },
+  }),
 
   /**
    * Called when a node param is changed.
    */
-  _onChangeParam: function({ actor, param, value }) {
-    window.emit(EVENTS.CHANGE_PARAM, gAudioNodes.get(actor.actorID), param, value);
-  }
+  _onChangeParam: Task.async(function* ({ actor, param, value }) {
+    let node = yield WebAudioEditorController.getNode(actor);
+    window.emit(EVENTS.CHANGE_PARAM, node, param, value);
+  })
 };

browser/devtools/webaudioeditor/test/browser.ini

@@ -11,6 +11,7 @@ support-files =
   doc_connect-multi-param.html
   doc_iframe-context.html
   doc_automation.html
+  doc_bug_1125817.html
   440hz_sine.ogg
   head.js
 
@@ -39,6 +40,7 @@ support-files =
 [browser_wa_reset-03.js]
 [browser_wa_reset-04.js]
 [browser_wa_navigate.js]
+[browser_wa_controller-01.js]
 
 [browser_wa_graph-click.js]
 [browser_wa_graph-markers.js]

browser/devtools/webaudioeditor/test/browser_wa_controller-01.js

@@ -0,0 +1,27 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/**
+ * Bug 1125817
+ * Tests to ensure that disconnecting a node immediately
+ * after creating it does not fail.
+ */
+
+const BUG_1125817_URL = EXAMPLE_URL + "doc_bug_1125817.html";
+
+add_task(function*() {
+  let { target, panel } = yield initWebAudioEditor(BUG_1125817_URL);
+  let { panelWin } = panel;
+  let { gFront, $, $$, EVENTS, gAudioNodes } = panelWin;
+
+  reload(target);
+
+  let [actors] = yield Promise.all([
+    once(gAudioNodes, "add", 2),
+    once(gAudioNodes, "disconnect")
+  ]);
+
+  ok(true, "Successfully disconnected a just-created node.");
+
+  yield teardown(target);
+});

browser/devtools/webaudioeditor/test/doc_bug_1125817.html

@@ -0,0 +1,23 @@
+<!-- Any copyright is dedicated to the Public Domain.
+     http://creativecommons.org/publicdomain/zero/1.0/ -->
+<!doctype html>
+
+<html>
+  <head>
+    <meta charset="utf-8"/>
+    <title>Web Audio Editor test page</title>
+  </head>
+
+  <body>
+
+    <script type="text/javascript;version=1.8">
+      "use strict";
+
+      let ctx = new AudioContext();
+      let osc = ctx.createOscillator();
+      osc.frequency.value = 200;
+      osc.disconnect();
+    </script>
+  </body>
+
+</html>