Bug 729384 - Create an interface for virtual cursor changed events. r=surkov.alexander

accessible/public/nsIAccessibleEvent.idl

@@ -571,3 +571,26 @@ interface nsIAccessibleTableChangeEvent: nsISupports
   readonly attribute long numRowsOrCols;
 };
 
+
+/*
+ * An interface for virtual cursor changed events.
+ * Passes previous cursor position and text offsets.
+ */
+[scriptable, uuid(370e8b9b-2bbc-4bff-a9c7-16ddc54aea21)]
+interface nsIAccessibleVirtualCursorChangeEvent : nsISupports
+{
+  /**
+   * Previous object pointed at by virtual cursor. null if none.
+   */
+  readonly attribute nsIAccessible oldAccessible;
+
+  /**
+   * Previous start offset of pivot. -1 if none.
+   */
+  readonly attribute long oldStartOffset;
+
+  /**
+   * Previous end offset of pivot. -1 if none.
+   */
+  readonly attribute long oldEndOffset;
+};

accessible/src/base/AccEvent.cpp

@@ -380,3 +380,24 @@ AccTableChangeEvent::CreateXPCOMObject()
   return event;
 }
 
+
+////////////////////////////////////////////////////////////////////////////////
+// AccVCChangeEvent
+////////////////////////////////////////////////////////////////////////////////
+
+AccVCChangeEvent::
+  AccVCChangeEvent(nsAccessible* aAccessible,
+                   nsIAccessible* aOldAccessible,
+                   PRInt32 aOldStart, PRInt32 aOldEnd) :
+    AccEvent(::nsIAccessibleEvent::EVENT_VIRTUALCURSOR_CHANGED, aAccessible),
+    mOldAccessible(aOldAccessible), mOldStart(aOldStart), mOldEnd(aOldEnd)
+{
+}
+
+already_AddRefed<nsAccEvent>
+AccVCChangeEvent::CreateXPCOMObject()
+{
+  nsAccEvent* event = new nsAccVirtualCursorChangeEvent(this);
+  NS_ADDREF(event);
+  return event;
+}

accessible/src/base/AccEvent.h

@@ -129,7 +129,8 @@ public:
     eShowEvent,
     eCaretMoveEvent,
     eSelectionChangeEvent,
-    eTableChangeEvent
+    eTableChangeEvent,
+    eVirtualCursorChangeEvent
   };
 
   static const EventGroup kEventGroup = eGenericEvent;
@@ -399,6 +400,37 @@ private:
   PRUint32 mNumRowsOrCols;   // the number of inserted/deleted rows/columns
 };
 
+/**
+ * Accessible virtual cursor change event.
+ */
+class AccVCChangeEvent : public AccEvent
+{
+public:
+  AccVCChangeEvent(nsAccessible* aAccessible,
+                   nsIAccessible* aOldAccessible,
+                   PRInt32 aOldStart, PRInt32 aOldEnd);
+
+  virtual ~AccVCChangeEvent() { }
+
+  // AccEvent
+  virtual already_AddRefed<nsAccEvent> CreateXPCOMObject();
+
+  static const EventGroup kEventGroup = eVirtualCursorChangeEvent;
+  virtual unsigned int GetEventGroups() const
+  {
+    return AccEvent::GetEventGroups() | (1U << eVirtualCursorChangeEvent);
+  }
+
+  // AccTableChangeEvent
+  nsIAccessible* OldAccessible() const { return mOldAccessible; }
+  PRInt32 OldStartOffset() const { return mOldStart; }
+  PRInt32 OldEndOffset() const { return mOldEnd; }
+
+private:
+  nsRefPtr<nsIAccessible> mOldAccessible;
+  PRInt32 mOldStart;
+  PRInt32 mOldEnd;
+};
 
 /**
  * Downcast the generic accessible event object to derived type.

accessible/src/base/nsDocAccessible.cpp

@@ -923,7 +923,8 @@ nsDocAccessible::OnPivotChanged(nsIAccessiblePivot* aPivot,
                                 nsIAccessible* aOldAccessible,
                                 PRInt32 aOldStart, PRInt32 aOldEnd)
 {
-  nsRefPtr<AccEvent> event = new AccEvent(nsIAccessibleEvent::EVENT_VIRTUALCURSOR_CHANGED, this);
+  nsRefPtr<AccEvent> event = new AccVCChangeEvent(this, aOldAccessible,
+                                                  aOldStart, aOldEnd);
   nsEventShell::FireEvent(event);
 
   return NS_OK;

accessible/src/xpcom/nsAccEvent.cpp

@@ -253,3 +253,40 @@ nsAccTableChangeEvent::GetNumRowsOrCols(PRInt32* aNumRowsOrCols)
   return NS_OK;
 }
 
+////////////////////////////////////////////////////////////////////////////////
+// nsAccVirtualCursorChangeEvent
+////////////////////////////////////////////////////////////////////////////////
+
+NS_IMPL_ISUPPORTS_INHERITED1(nsAccVirtualCursorChangeEvent, nsAccEvent,
+                             nsIAccessibleVirtualCursorChangeEvent)
+
+NS_IMETHODIMP
+nsAccVirtualCursorChangeEvent::GetOldAccessible(nsIAccessible** aOldAccessible)
+{
+  NS_ENSURE_ARG_POINTER(aOldAccessible);
+
+  *aOldAccessible =
+    static_cast<AccVCChangeEvent*>(mEvent.get())->OldAccessible();
+  NS_IF_ADDREF(*aOldAccessible);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsAccVirtualCursorChangeEvent::GetOldStartOffset(PRInt32* aOldStartOffset)
+{
+  NS_ENSURE_ARG_POINTER(aOldStartOffset);
+
+  *aOldStartOffset =
+    static_cast<AccVCChangeEvent*>(mEvent.get())->OldStartOffset();
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsAccVirtualCursorChangeEvent::GetOldEndOffset(PRInt32* aOldEndOffset)
+{
+  NS_ENSURE_ARG_POINTER(aOldEndOffset);
+
+  *aOldEndOffset =
+    static_cast<AccVCChangeEvent*>(mEvent.get())->OldEndOffset();
+  return NS_OK;
+}

accessible/src/xpcom/nsAccEvent.h

@@ -164,5 +164,25 @@ private:
   nsAccTableChangeEvent& operator =(const nsAccTableChangeEvent&);
 };
 
+/**
+ * Accessible virtual cursor change event.
+ */
+class nsAccVirtualCursorChangeEvent : public nsAccEvent,
+                                      public nsIAccessibleVirtualCursorChangeEvent
+{
+public:
+  nsAccVirtualCursorChangeEvent(AccVCChangeEvent* aEvent) :
+    nsAccEvent(aEvent) { }
+  virtual ~nsAccVirtualCursorChangeEvent() { }
+
+  NS_DECL_ISUPPORTS_INHERITED
+  NS_DECL_NSIACCESSIBLEVIRTUALCURSORCHANGEEVENT
+
+private:
+  nsAccVirtualCursorChangeEvent() MOZ_DELETE;
+  nsAccVirtualCursorChangeEvent(const nsAccVirtualCursorChangeEvent&) MOZ_DELETE;
+  nsAccVirtualCursorChangeEvent& operator =(const nsAccVirtualCursorChangeEvent&) MOZ_DELETE;
+};
+
 #endif