Bug 926812 - State change event not fired when both disabled and aria-disabled are toggled, r=tbsaunde

accessible/src/generic/Accessible.h

@@ -244,6 +244,16 @@ public:
     return state;
   }
 
+  /**
+   * Return if accessible is unavailable.
+   */
+  bool Unavailable() const
+  {
+    uint64_t state = NativelyUnavailable() ? states::UNAVAILABLE : 0;
+    ApplyARIAState(&state);
+    return state & states::UNAVAILABLE;
+  }
+
   /**
    * Return the states of accessible, not taking into account ARIA states.
    * Use State() to get complete set of states.

accessible/src/generic/DocAccessible.cpp

@@ -870,7 +870,12 @@ DocAccessible::AttributeWillChange(nsIDocument* aDocument,
       aAttribute == nsGkAtoms::aria_pressed) {
     mARIAAttrOldValue = (aModType != nsIDOMMutationEvent::ADDITION) ?
       nsAccUtils::GetARIAToken(aElement, aAttribute) : nullptr;
+    return;
   }
+
+  if (aAttribute == nsGkAtoms::aria_disabled ||
+      aAttribute == nsGkAtoms::disabled)
+    mStateBitWasOn = accessible->Unavailable();
 }
 
 void
@@ -938,22 +943,24 @@ DocAccessible::AttributeChangedImpl(Accessible* aAccessible,
 
   // Universal boolean properties that don't require a role. Fire the state
   // change when disabled or aria-disabled attribute is set.
+  // Note. Checking the XUL or HTML namespace would not seem to gain us
+  // anything, because disabled attribute really is going to mean the same
+  // thing in any namespace.
+  // Note. We use the attribute instead of the disabled state bit because
+  // ARIA's aria-disabled does not affect the disabled state bit.
   if (aAttribute == nsGkAtoms::disabled ||
       aAttribute == nsGkAtoms::aria_disabled) {
-
-    // Note. Checking the XUL or HTML namespace would not seem to gain us
-    // anything, because disabled attribute really is going to mean the same
-    // thing in any namespace.
-
-    // Note. We use the attribute instead of the disabled state bit because
-    // ARIA's aria-disabled does not affect the disabled state bit.
+    // Do nothing if state wasn't changed (like @aria-disabled was removed but
+    // @disabled is still presented).
+    if (aAccessible->Unavailable() == mStateBitWasOn)
+      return;
 
     nsRefPtr<AccEvent> enabledChangeEvent =
-      new AccStateChangeEvent(aAccessible, states::ENABLED);
+      new AccStateChangeEvent(aAccessible, states::ENABLED, mStateBitWasOn);
     FireDelayedEvent(enabledChangeEvent);
 
     nsRefPtr<AccEvent> sensitiveChangeEvent =
-      new AccStateChangeEvent(aAccessible, states::SENSITIVE);
+      new AccStateChangeEvent(aAccessible, states::SENSITIVE, mStateBitWasOn);
     FireDelayedEvent(sensitiveChangeEvent);
     return;
   }

accessible/src/generic/DocAccessible.h

@@ -533,10 +533,16 @@ protected:
   nsCOMPtr<nsIContent> mAnchorJumpElm;
 
   /**
-   * Keep the ARIA attribute old value that is initialized by
-   * AttributeWillChange and used by AttributeChanged notifications.
+   * A generic state (see items below) before the attribute value was changed.
+   * @see AttributeWillChange and AttributeChanged notifications.
    */
-  nsIAtom* mARIAAttrOldValue;
+  union {
+    // ARIA attribute value
+    nsIAtom* mARIAAttrOldValue;
+
+    // True if the accessible state bit was on
+    bool mStateBitWasOn;
+  };
 
   nsTArray<nsRefPtr<DocAccessible> > mChildDocuments;
 

accessible/tests/mochitest/events.js

@@ -1959,7 +1959,12 @@ var gA11yEventObserver =
         var type = eventTypeToString(event.eventType);
         var info = "Event type: " + type;
 
-        if (event instanceof nsIAccessibleTextChangeEvent) {
+        if (event instanceof nsIAccessibleStateChangeEvent) {
+          var stateStr = statesToString(event.isExtraState ? 0 : event.state,
+                                        event.isExtraState ? event.state : 0);
+          info += ", state: " + stateStr + ", is enabled: " + event.isEnabled;
+
+        } else if (event instanceof nsIAccessibleTextChangeEvent) {
           info += ", start: " + event.start + ", length: " + event.length +
             ", " + (event.isInserted ? "inserted" : "removed") +
             " text: " + event.modifiedText;

accessible/tests/mochitest/events/test_statechange.html

@@ -143,18 +143,46 @@
         new stateChangeChecker(aState, aIsExtraState, true, getNode(aID))
       ];
 
-      this.invoke = function dupeStateChange_invoke()
+      this.invoke = function oppositeStateChange_invoke()
       {
         getNode(aID).setAttribute(aAttr, "false");
         getNode(aID).setAttribute(aAttr, "true");
       }
 
-      this.getID = function dupeStateChange_getID()
+      this.getID = function oppositeStateChange_getID()
       {
         return "opposite state change events";
       }
     }
 
+    /**
+     * Change concomitant ARIA and native attribute at once.
+     */
+    function echoingStateChange(aID, aARIAAttr, aAttr, aValue,
+                               aState, aIsExtraState, aIsEnabled)
+    {
+      this.eventSeq = [
+        new stateChangeChecker(aState, aIsExtraState, aIsEnabled, getNode(aID))
+      ];
+
+      this.invoke = function echoingStateChange_invoke()
+      {
+        if (aValue == null) {
+          getNode(aID).removeAttribute(aARIAAttr);
+          getNode(aID).removeAttribute(aAttr);
+
+        } else {
+          getNode(aID).setAttribute(aARIAAttr, aValue);
+          getNode(aID).setAttribute(aAttr, aValue);
+        }
+      }
+
+      this.getID = function echoingStateChange_getID()
+      {
+        return "enchoing ARIA and native attributes change";
+      }
+    }
+
     ////////////////////////////////////////////////////////////////////////////
     // Do tests
 
@@ -193,6 +221,11 @@
       gQueue.push(new oppositeStateChange("div", "aria-busy",
                                           STATE_BUSY, false));
 
+      gQueue.push(new echoingStateChange("text1", "aria-disabled", "disabled", "true",
+                                         EXT_STATE_ENABLED, true, false));
+      gQueue.push(new echoingStateChange("text1", "aria-disabled", "disabled", null,
+                                         EXT_STATE_ENABLED, true, true));
+
       gQueue.invoke(); // Will call SimpleTest.finish();
     }
 
@@ -223,6 +256,11 @@
      title="Fire statechange event whenever checked state is changed not depending on focused state">
     Bug 788389
   </a>
+  <a target="_blank"
+     href="https://bugzilla.mozilla.org/show_bug.cgi?id=926812"
+     title="State change event not fired when both disabled and aria-disabled are toggled">
+    Bug 926812
+  </a>
 
   <p id="display"></p>
   <div id="content" style="display: none"></div>
@@ -242,6 +280,8 @@
 
   <div id="div"></div>
 
+  <input id="text1">
+
   <div id="eventdump"></div>
 </body>
 </html>