Implement ChromeVox next/previous line, link, and heading.

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('cvox2.Background');
 goog.provide('cvox2.global');
 
 goog.require('cvox.TabsApiHandler');
+goog.require('cvox2.AutomationPredicates');
+goog.require('cvox2.AutomationUtil');
 
 /** Classic Chrome accessibility API. */
 cvox2.global.accessibility =
     chrome.accessibilityPrivate || chrome.experimental.accessibility;
 
 /**
  * ChromeVox2 background page.
  */
 cvox2.Background = function() {
   /**
    * A list of site substring patterns to use with ChromeVox next. Keep these
    * strings relatively specific.
    * @type {!Array.<string>}
    */
   this.whitelist_ = ['http://www.chromevox.com/', 'chromevox_next_test'];
 
   /** @type {cvox.TabsApiHandler} @private */
   this.tabsHandler_ = new cvox.TabsApiHandler(cvox.ChromeVox.tts,
                                               cvox.ChromeVox.braille,
                                               cvox.ChromeVox.earcons);
 
+  /** @type {AutomationNode} @private */
+  this.currentNode_ = null;
+
+  /** @type {cvox.TabsApiHandler} @private */
+  this.tabsHandler_ = new cvox.TabsApiHandler(cvox.ChromeVox.tts,
+                                              cvox.ChromeVox.braille,
+                                              cvox.ChromeVox.earcons);
+
   // Only needed with unmerged ChromeVox classic loaded before.
   cvox2.global.accessibility.setAccessibilityEnabled(false);
 
   // Manually bind all functions to |this|.
   for (var func in this) {
     if (typeof(this[func]) == 'function')
       this[func] = this[func].bind(this);
   }
 
   // Register listeners for ...
@@ skipping 14 matching lines @@
     chrome.tabs.get(tabId, function(tab) {
       if (!tab.url)
         return;
 
       if (!this.isWhitelisted_(tab.url)) {
         chrome.commands.onCommand.removeListener(this.onGotCommand);
         cvox.ChromeVox.background.injectChromeVoxIntoTabs([tab], true);
         return;
       }
 
-      if (!chrome.commands.onCommand.hasListeners()) {
+      if (!chrome.commands.onCommand.hasListeners())
         chrome.commands.onCommand.addListener(this.onGotCommand);
-      }
 
       this.disableClassicChromeVox_(tab.id);
 
       chrome.automation.getTree(this.onGotTree.bind(this));
     }.bind(this));
   },
 
   /**
    * Handles all setup once a new automation tree appears.
    * @param {AutomationTree} tree The new automation tree.
    */
   onGotTree: function(root) {
     // Register all automation event listeners.
     root.addEventListener(chrome.automation.EventType.focus,
-                          this.onAutomationEvent.bind(this),
+                          this.onFocus,
                           true);
-  },
+    root.addEventListener(chrome.automation.EventType.loadComplete,
+                          this.onLoadComplete,
+                          true);
 
-  /**
-   * A generic handler for all desktop automation events.
-   * @param {AutomationEvent} evt The event.
-   */
-  onAutomationEvent: function(evt) {
-    var output = evt.target.attributes.name + ' ' + evt.target.role;
-    cvox.ChromeVox.tts.speak(output, cvox.AbstractTts.QUEUE_MODE_FLUSH);
-    cvox.ChromeVox.braille.write(cvox.NavBraille.fromText(output));
+    if (root.attributes.docLoaded)
+      this.onLoadComplete({target: root});
   },
 
   /**
    * Handles chrome.commands.onCommand.
    * @param {string} command
    */
   onGotCommand: function(command) {
+    if (!this.current_)
+      return;
+
+    var previous = this.current_;
+    var current = this.current_;
+
+    // Reverse?
+    var r = false;
+    var pred = null;
+    switch (command) {
+      case 'nextHeading':
+        r = false;
+        pred = cvox2.AutomationPredicates.heading;
+        break;
+      case 'previousHeading':
+        r = true;
+        pred = cvox2.AutomationPredicates.heading;
+        break;
+      case 'nextLine':
+        r = false;
+        pred = cvox2.AutomationPredicates.inlineTextBox;
+        break;
+      case 'previousLine':
+        r = true;
+        pred = cvox2.AutomationPredicates.inlineTextBox;
+        break;
+      case 'nextLink':
+        r = false;
+        pred = cvox2.AutomationPredicates.link;
+        break;
+      case 'previousLink':
+        r = true;
+        pred = cvox2.AutomationPredicates.link;
+        break;
+      case 'nextElement':
+        current = current.role == chrome.automation.RoleType.inlineTextBox ?
+            current.parent() : current;
+        current = cvox2.AutomationUtil.findNextNode(current,
+            false,
+            cvox2.AutomationPredicates.inlineTextBox);
+        current = current ? current.parent() : current;
+        break;
+      case 'previousElement':
+        current = current.role == chrome.automation.RoleType.inlineTextBox ?
+            current.parent() : current;
+        current = cvox2.AutomationUtil.findNextNode(current,
+            true,
+            cvox2.AutomationPredicates.inlineTextBox);
+        current = current ? current.parent() : current;
+        break;
+    }
+
+    if (pred)
+      current = cvox2.AutomationUtil.findNextNode(current, r, pred);
+
+    if (current)
+      current.focus();
+
+    this.onFocus({target: current || previous});
   },
 
   /**
+   * Provides all feedback once ChromeVox's focus changes.
+   * @param {Object} evt

[dmazzoni, 2014/09/29 06:06:18]

Is there a specific automation api type rather than {Object}?

[David Tseng, 2014/09/29 17:05:23]

See below.

+   */
+  onFocus: function(evt) {
+    var node = evt.target;
+    if (!node)
+      return;
+    var container = node;
+    while (container && (container.role == 'inlineTextBox' ||
+        container.role == 'staticText'))
+      container = container.parent();
+
+    var role = container ? container.role : node.role;
+
+    var output =
+        [node.attributes.name, node.attributes.value, role].join(', ');
+    cvox.ChromeVox.tts.speak(output, cvox.AbstractTts.QUEUE_MODE_FLUSH);
+    cvox.ChromeVox.braille.write(cvox.NavBraille.fromText(output));
+    this.current_ = node;
+  },
+
+  /**
+   * Provides all feedback once a load complete event fires.
+   * @param {Object} evt

[dmazzoni, 2014/09/29 06:06:18]

Is there a specific automation api type rather than {Object}?

[David Tseng, 2014/09/29 17:05:23]

No; nothing defined on chrome.automation at least. Extension API object types
don't get defined anywhere; we could do something custom for automation (which
is what I did for the enum types).

+   */
+  onLoadComplete: function(evt) {
+    this.current_ = cvox2.AutomationUtil.findNodePost(evt.target,
+        false,
+        cvox2.AutomationPredicates.inlineTextBox);
+    this.onFocus({target: this.current_});
+  },
+
+  /**
    * @private
    * @param {string} url
    * @return {boolean} Whether the given |url| is whitelisted.
    */
   isWhitelisted_: function(url) {
     return this.whitelist_.some(function(item) {
       return url.indexOf(item) != -1;
     }.bind(this));
   },
 
   /**
    * Disables classic ChromeVox.
-   * @param {number} tabId The tab where ChromeVox classic is running.
+   * @param {number} tabId The tab where ChromeVox classic is running in.
    */
   disableClassicChromeVox_: function(tabId) {
     chrome.tabs.executeScript(
           tabId,
           {'code': 'try { window.disableChromeVox(); } catch(e) { }\n',
            'allFrames': true});
   }
 };
 
 /** @type {cvox2.Background} */
 cvox2.global.backgroundObj = new cvox2.Background();