Complete live region support in ChromeVox Next.

chrome/browser/resources/chromeos/chromevox/cvox2/background/background.js

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 /**
  * @fileoverview The entry point for all ChromeVox2 related code for the
  * background page.
  */
 
 goog.provide('Background');
@@ skipping 57 matching lines @@
    */
   this.currentRange_ = null;
 
   /**
    * Which variant of ChromeVox is active.
    * @type {ChromeVoxMode}
    * @private
    */
   this.mode_ = ChromeVoxMode.COMPAT;
 
+  /**
+   * The time the last live region event was output.
+   * @type {Date}
+   * @private
+   */
+  this.lastLiveRegionTime_ = new Date(0);
+
+  /**
+   * Ids of nodes that have been announced as part of a live region since

[Peter Lundblad, 2015/11/20 13:42:58]

nit: there are no ids stored in the set.

[dmazzoni, 2015/11/23 20:16:50]

Done.

+   *     |this.lastLiveRegionTime_|, to prevent duplicate announcements.
+   * @type {WeakSet}

[Peter Lundblad, 2015/11/20 13:42:58]

{!WeakSet}
Does the compiler support
{!WeakSet<AutomationNode>}
? It worked when I used for a Map.

[dmazzoni, 2015/11/23 20:16:50]

It worked! Thanks.

+   * @private
+   */
+  this.liveRegionNodeSet_ = new WeakSet();
+
   // Manually bind all functions to |this|.
   for (var func in this) {
     if (typeof(this[func]) == 'function')
       this[func] = this[func].bind(this);
   }
 
   /** @type {!cvox.AbstractEarcons} @private */
   this.classicEarcons_ = cvox.ChromeVox.earcons || new cvox.ClassicEarcons();
 
   /** @type {!cvox.AbstractEarcons} @private */
@@ skipping 30 matching lines @@
   });
 
   cvox.ExtensionBridge.addMessageListener(this.onMessage_);
 
   document.addEventListener('keydown', this.onKeyDown.bind(this), true);
   cvox.ChromeVoxKbHandler.commandHandler = this.onGotCommand.bind(this);
 
   // Classic keymap.
   cvox.ChromeVoxKbHandler.handlerKeyMap = cvox.KeyMap.fromDefaults();
 
+  chrome.automation.setTreeChangeObserverMask('liveRegionTreeChanges');
   chrome.automation.addTreeChangeObserver(this.onTreeChange);
 };
 
+/**
+ * Live region events received in fewer than this many milliseconds will
+ * queue, otherwise they'll be output with a category flush.
+ * @type {number}
+ * @const
+ */
+Background.LIVE_REGION_QUEUE_TIME_MS = 500;
+
 Background.prototype = {
   /** Forces ChromeVox Next to be active for all tabs. */
   forceChromeVoxNextActive: function() {
     this.setChromeVoxMode(ChromeVoxMode.FORCE_NEXT);
   },
 
   /** @type {ChromeVoxMode} */
   get mode() {
     return this.mode_;
   },
@@ skipping 276 matching lines @@
    * Handles key down events.
    * @param {Event} evt The key down event to process.
    * @return {boolean} True if the default action should be performed.
    */
   onKeyDown: function(evt) {
     if (this.mode_ != ChromeVoxMode.CLASSIC &&
         !cvox.ChromeVoxKbHandler.basicKeyDownActionsListener(evt)) {
       evt.preventDefault();
       evt.stopPropagation();
     }
+
+    Output.flushNextSpeechUtterance();
   },
 
   /**
    * Open the options page in a new tab.
    */
   showOptionsPage: function() {
     var optionsPage = {url: 'chromevox/background/options.html'};
     chrome.tabs.create(optionsPage);
   },
 
@@ skipping 54 matching lines @@
     }
 
     this.setChromeVoxMode(mode);
   },
 
   /**
    * Called when the automation tree is changed.
    * @param {chrome.automation.TreeChange} treeChange
    */
   onTreeChange: function(treeChange) {
-    if (this.mode_ === ChromeVoxMode.CLASSIC || !cvox.ChromeVox.isActive)
-      return;
-
     var node = treeChange.target;
     if (!node.containerLiveStatus)
       return;
 
-    if (node.containerLiveRelevant.indexOf('additions') >= 0 &&
-        treeChange.type == 'nodeCreated')
-      this.outputLiveRegionChange_(node, null);
-    if (node.containerLiveRelevant.indexOf('text') >= 0 &&
-        treeChange.type == 'nodeChanged')
-      this.outputLiveRegionChange_(node, null);
-    if (node.containerLiveRelevant.indexOf('removals') >= 0 &&
-        treeChange.type == 'nodeRemoved')
-      this.outputLiveRegionChange_(node, '@live_regions_removed');
+    var skip = false;

[Peter Lundblad, 2015/11/20 13:42:58]

Get rid of this and return early instead?

[dmazzoni, 2015/11/23 20:16:50]

Done.

+
+    if (this.mode_ === ChromeVoxMode.CLASSIC || !cvox.ChromeVox.isActive) {
+      skip = true;
+    } else if (!this.currentRange_) {
+      skip = true;
+    } else if (!AutomationUtil.isInSameWebpage(
+        node, this.currentRange_.start.node)) {
+      skip = true;
+    }
+
+    if (!skip) {
+      var type = treeChange.type;
+      var relevant = node.containerLiveRelevant;
+      if (relevant.indexOf('additions') >= 0 &&

[David Tseng, 2015/11/24 18:46:30]

Where do relevant strings come from? This looks pretty error prone.

[dmazzoni, 2015/11/30 22:02:47]

This is from the ARIA spec, I'm not sure we should define them ourselves.

FWIW, we don't try to parse the string because this is the format some native
APIs want anyway (they just want the validated string value of the ARIA
attribute).

+          (type == 'nodeCreated' || type == 'subtreeCreated')) {
+        this.outputLiveRegionChange_(node, null);
+      }
+      if (relevant.indexOf('text') >= 0 && type == 'nodeChanged')
+        this.outputLiveRegionChange_(node, null);
+      if (relevant.indexOf('removals') >= 0 && type == 'nodeRemoved')
+        this.outputLiveRegionChange_(node, '@live_regions_removed');
+    }
   },
 
   /**
    * Given a node that needs to be spoken as part of a live region
    * change and an additional optional format string, output the
    * live region description.
    * @param {!chrome.automation.AutomationNode} node The changed node.
    * @param {?string} opt_prependFormatStr If set, a format string for
    *     cvox2.Output to prepend to the output.
    * @private
    */
   outputLiveRegionChange_: function(node, opt_prependFormatStr) {
+    if (node.containerLiveBusy)
+      return;
+
+    if (node.containerLiveAtomic && !node.liveAtomic) {
+      if (node.parent)
+        this.outputLiveRegionChange_(node.parent, opt_prependFormatStr);
+      return;
+    }
+
     var range = cursors.Range.fromNode(node);
     var output = new Output();
     if (opt_prependFormatStr) {
       output.format(opt_prependFormatStr);
     }
-    output.withSpeech(range, null, Output.EventType.NAVIGATE);
+    output.withSpeech(range, range, Output.EventType.NAVIGATE);
+
+    if (output.empty && node.liveAtomic) {
+      output.format('$descendants', node);
+    }
+
     output.withSpeechCategory(cvox.TtsCategory.LIVE);
+
+    if (output.empty)
+      return;
+
+    // Enqueue live region updates that were received at approximately
+    // the same time, otherwise flush previous live region updates.
+    var currentTime = new Date();
+    var queueTime = Background.LIVE_REGION_QUEUE_TIME_MS;
+    if (currentTime - this.lastLiveRegionTime_ > queueTime) {
+      this.liveRegionNodeSet_ = new WeakSet();
+      output.withQueueMode(cvox.QueueMode.CATEGORY_FLUSH);
+      this.lastLiveRegionTime_ = currentTime;
+    } else {
+      output.withQueueMode(cvox.QueueMode.QUEUE);
+    }
+
+    var parent = node;
+    while (parent) {
+      if (this.liveRegionNodeSet_.has(parent))
+        return;
+      parent = parent.parent;
+    }
+
+    this.liveRegionNodeSet_.add(node);
     output.go();
   },
 
   /**
    * Returns true if the url should have Classic running.
    * @return {boolean}
    * @private
    */
   shouldEnableClassicForUrl_: function(url) {
     return this.mode_ != ChromeVoxMode.FORCE_NEXT &&
@@ skipping 140 matching lines @@
     return glob.replace(/[.+^$(){}|[\]\\]/g, '\\$&')
         .replace(/\*/g, '.*')
         .replace(/\?/g, '.');
   }).join('|') + ')$');
 };
 
 /** @type {Background} */
 global.backgroundObj = new Background();
 
 });  // goog.scope