Initial support for Ranges over automation nodes (used to track ChromeVox focus).

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

Index: chrome/browser/resources/chromeos/chromevox/cvox2/background/background.js
diff --git a/chrome/browser/resources/chromeos/chromevox/cvox2/background/background.js b/chrome/browser/resources/chromeos/chromevox/cvox2/background/background.js
index 989adde5b82d5d71802bc216b9a0bd801762a9d1..d09a1de2e57e08fb825e4c13f586e7e150b215af 100644
--- a/chrome/browser/resources/chromeos/chromevox/cvox2/background/background.js
+++ b/chrome/browser/resources/chromeos/chromevox/cvox2/background/background.js
@@ -16,9 +16,9 @@ goog.require('cursors.Cursor');
 goog.require('cvox.TabsApiHandler');
 
 goog.scope(function() {
+var AutomationNode = chrome.automation.AutomationNode;
 var Dir = AutomationUtil.Dir;
 var EventType = chrome.automation.EventType;
-var AutomationNode = chrome.automation.AutomationNode;
 
 /** Classic Chrome accessibility API. */
 global.accessibility =
@@ -46,10 +46,10 @@ Background = function() {
                                               cvox.ChromeVox.earcons);
 
   /**
-   * @type {chrome.automation.AutomationNode}
+   * @type {cursors.Range}
    * @private
    */
-  this.currentNode_ = null;
+  this.activeRange_ = null;

[dmazzoni, 2014/10/24 16:13:30]

Since we use "active" to mean whether ChromeVox is active at all, and since
you're using "current" as the local variable name, maybe this should be
currentRange_?

Alternate idea: virtualRange (like virtual cursor)

Or, we could rename active_ to running_?

Sorry to nitpick, but it seems like the best time to get these things right
while the ChromeVox Next codebase is small. It will make it so much more
readable in the future.

 
   /**
    * Whether ChromeVox Next is active.
@@ -129,12 +129,10 @@ Background.prototype = {
       return;
     }
 
-    if (!this.active_ || !this.current_)
+    if (!this.active_ || !this.activeRange_)
       return;
 
-    var previous = this.current_;
-    var current = this.current_;
-
+    var current = this.activeRange_;
     var dir = Dir.FORWARD;
     var pred = null;
     switch (command) {
@@ -147,12 +145,10 @@ Background.prototype = {
         pred = AutomationPredicate.heading;
         break;
       case 'nextLine':
-        dir = Dir.FORWARD;
-        pred = AutomationPredicate.inlineTextBox;
+        current = current.move(cursors.Unit.LINE, Dir.FORWARD);
         break;
       case 'previousLine':
-        dir = Dir.BACKWARD;
-        pred = AutomationPredicate.inlineTextBox;
+        current = current.move(cursors.Unit.LINE, Dir.BACKWARD);
         break;
       case 'nextLink':
         dir = Dir.FORWARD;
@@ -163,40 +159,41 @@ Background.prototype = {
         pred = AutomationPredicate.link;
         break;
       case 'nextElement':
-        current = current.role == chrome.automation.RoleType.inlineTextBox ?
-            current.parent() : current;
-        current = AutomationUtil.findNextNode(current,
-            Dir.FORWARD,
-            AutomationPredicate.inlineTextBox);
-        current = current ? current.parent() : current;
+        current = current.move(cursors.Unit.NODE, Dir.FORWARD);
         break;
       case 'previousElement':
-        current = current.role == chrome.automation.RoleType.inlineTextBox ?
-            current.parent() : current;
-        current = AutomationUtil.findNextNode(current,
-            Dir.BACKWARD,
-            AutomationPredicate.inlineTextBox);
-        current = current ? current.parent() : current;
+        current = current.move(cursors.Unit.NODE, Dir.BACKWARD);
         break;
       case 'goToBeginning':
-        current = AutomationUtil.findNodePost(current.root,
+      var node = AutomationUtil.findNodePost(current.getStart().getNode().root,
             Dir.FORWARD,
-            AutomationPredicate.inlineTextBox);
+            AutomationPredicate.leaf);
+      if (node)
+        current = cursors.Range.fromNode(node);
         break;
       case 'goToEnd':
-        current = AutomationUtil.findNodePost(current.root,
+      var node =
+          AutomationUtil.findNodePost(current.getStart().getNode().root,
             Dir.BACKWARD,
-            AutomationPredicate.inlineTextBox);
+            AutomationPredicate.leaf);
+      if (node)
+        current = cursors.Range.fromNode(node);
         break;
     }
 
-    if (pred)
-      current = AutomationUtil.findNextNode(current, dir, pred);
+    if (pred) {
+      var node = AutomationUtil.findNextNode(
+          current.getBound(dir).getNode(), dir, pred);
+
+      if (node)
+        current = cursors.Range.fromNode(node);
+    }
 
     if (current) {
-      current.focus();
+      current.getStart().getNode().focus();

[dmazzoni, 2014/10/24 16:13:29]

Perhaps this should call a method on current that says to focus any focusable
elements contained within the range? For example, if the active range is a
single line containing a link, we should focus the link even though it's not the
start node.

OK to just mark as TODO, or write the helper function but not fully implement it
yet.

 
-      this.onFocus({target: current});
+      this.activeRange_ = current;
+      this.handleOutput(this.activeRange_);
     }
   },
 
@@ -209,20 +206,8 @@ Background.prototype = {
     if (!node)
       return;
 
-    this.current_ = node;
-    var container = node;
-    while (container &&
-        (container.role == chrome.automation.RoleType.inlineTextBox ||
-        container.role == chrome.automation.RoleType.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.QueueMode.FLUSH);
-    cvox.ChromeVox.braille.write(cvox.NavBraille.fromText(output));
-    chrome.accessibilityPrivate.setFocusRing([evt.target.location]);
+    this.activeRange_ = cursors.Range.fromNode(node);
+    this.handleOutput(this.activeRange_);
   },
 
   /**
@@ -230,13 +215,17 @@ Background.prototype = {
    * @param {Object} evt
    */
   onLoadComplete: function(evt) {
-    if (this.current_)
+    if (this.activeRange_)
       return;
 
-    this.current_ = AutomationUtil.findNodePost(evt.target,
+    var node = AutomationUtil.findNodePost(evt.target,
         Dir.FORWARD,
-        AutomationPredicate.inlineTextBox);
-    this.onFocus({target: this.current_});
+        AutomationPredicate.leaf);
+    if (node)
+      this.activeRange_ = cursors.Range.fromNode(node);
+
+    if (this.activeRange_)
+      this.handleOutput(this.activeRange_);
   },
 
   /**
@@ -278,7 +267,7 @@ Background.prototype = {
     } else {
       if (this.active_) {
         for (var eventType in this.listeners_) {
-          this.current_.root.removeEventListener(
+          this.activeRange_.getStart().getNode().root.removeEventListener(
               eventType, this.listeners_[eventType], true);
         }
       }
@@ -294,6 +283,43 @@ Background.prototype = {
         }.bind(this));
       }
     }.bind(this));
+  },
+
+  /**
+   * Handles output of a Range.
+   * @param {!cursors.Range} range Current location.
+   */
+  handleOutput: function(range) {
+    // TODO(dtseng): This is just placeholder logic for generating descriptions
+    // pending further design discussion.
+    function getCursorDesc(cursor) {
+      var node = cursor.getNode();
+      var container = node;
+      while (container &&
+          (container.role == chrome.automation.RoleType.inlineTextBox ||
+          container.role == chrome.automation.RoleType.staticText))
+        container = container.parent();
+
+      var role = container ? container.role : node.role;
+      return [node.attributes.name, node.attributes.value, role].join(', ');
+    }
+
+    // Walk the range and collect descriptions.
+    var output = '';
+    var cursor = range.getStart();
+    var nodeLocations = [];
+    while (cursor.getNode() != range.getEnd().getNode()) {
+      output += getCursorDesc(cursor);
+      nodeLocations.push(cursor.getNode().location);
+      cursor = cursor.move(
+          cursors.Unit.NODE, cursors.Movement.DIRECTIONAL, Dir.FORWARD);
+    }
+    output += getCursorDesc(range.getEnd());
+    nodeLocations.push(range.getEnd().getNode().location);
+
+    cvox.ChromeVox.tts.speak(output, cvox.QueueMode.FLUSH);
+    cvox.ChromeVox.braille.write(cvox.NavBraille.fromText(output));
+    chrome.accessibilityPrivate.setFocusRing(nodeLocations);
   }
 };