bug 713792 - stop QueryInterface()ing to nsIAccessible image internally r=tbsaunde

accessible/src/atk/nsAccessibleWrap.cpp

@@ -449,13 +449,8 @@ nsAccessibleWrap::CreateMaiInterfaces(void)
         interfacesBits |= 1 << MAI_INTERFACE_DOCUMENT;
     }
 
-    //nsIAccessibleImage
-    nsCOMPtr<nsIAccessibleImage> accessInterfaceImage;
-    QueryInterface(NS_GET_IID(nsIAccessibleImage),
-                              getter_AddRefs(accessInterfaceImage));
-    if (accessInterfaceImage) {
+    if (IsImageAccessible())
         interfacesBits |= 1 << MAI_INTERFACE_IMAGE;
-    }
 
   // HyperLinkAccessible
   if (IsLink())

accessible/src/atk/nsMaiInterfaceImage.cpp

@@ -37,9 +37,11 @@
  *
  * ***** END LICENSE BLOCK ***** */
 
-#include "nsAccessibleWrap.h"
 #include "nsMaiInterfaceImage.h"
 
+#include "nsAccessibleWrap.h"
+#include "nsHTMLImageAccessible.h"
+
 extern "C" const gchar* getDescriptionCB(AtkObject* aAtkObj);
 
 void
@@ -58,19 +60,13 @@ getImagePositionCB(AtkImage *aImage, gint *aAccX, gint *aAccY,
                    AtkCoordType aCoordType)
 {
     nsAccessibleWrap *accWrap = GetAccessibleWrap(ATK_OBJECT(aImage));
-    if (!accWrap) 
-      return;
-
-    nsCOMPtr<nsIAccessibleImage> image;
-    accWrap->QueryInterface(NS_GET_IID(nsIAccessibleImage),
-                            getter_AddRefs(image));
-    if (!image)
+    if (!accWrap || !accWrap->IsImageAccessible())
       return;
 
+    nsHTMLImageAccessible* image = accWrap->AsImage();
     PRUint32 geckoCoordType = (aCoordType == ATK_XY_WINDOW) ?
       nsIAccessibleCoordinateType::COORDTYPE_WINDOW_RELATIVE :
       nsIAccessibleCoordinateType::COORDTYPE_SCREEN_RELATIVE;
-
     // Returned in screen coordinates
     image->GetImagePosition(geckoCoordType, aAccX, aAccY);
 }
@@ -85,14 +81,8 @@ void
 getImageSizeCB(AtkImage *aImage, gint *aAccWidth, gint *aAccHeight)
 {
     nsAccessibleWrap *accWrap = GetAccessibleWrap(ATK_OBJECT(aImage));
-    if (!accWrap) 
+    if (!accWrap || !accWrap->IsImageAccessible())
       return;
 
-    nsCOMPtr<nsIAccessibleImage> image;
-    accWrap->QueryInterface(NS_GET_IID(nsIAccessibleImage),
-                            getter_AddRefs(image));
-    if (!image)
-      return;
-
-    image->GetImageSize(aAccWidth, aAccHeight);
+    accWrap->AsImage()->GetImageSize(aAccWidth, aAccHeight);
 }

accessible/src/base/nsAccessible.h

@@ -60,6 +60,7 @@ class EmbeddedObjCollector;
 class KeyBinding;
 class nsAccessible;
 class nsHyperTextAccessible;
+class nsHTMLImageAccessible;
 class nsHTMLLIAccessible;
 struct nsRoleMapEntry;
 class Relation;
@@ -429,6 +430,9 @@ public:
   inline bool IsHTMLListItem() const { return mFlags & eHTMLListItemAccessible; }
   nsHTMLLIAccessible* AsHTMLListItem();
   
+  inline bool IsImageAccessible() const { return mFlags & eImageAccessible; }
+  nsHTMLImageAccessible* AsImage();
+
   inline bool IsListControl() const { return mFlags & eListControlAccessible; }
 
   inline bool IsMenuButton() const { return mFlags & eMenuButtonAccessible; }
@@ -654,11 +658,12 @@ protected:
     eHyperTextAccessible = 1 << 7,
     eHTMLFileInputAccessible = 1 << 8,
     eHTMLListItemAccessible = 1 << 9,
-    eListControlAccessible = 1 << 10,
-    eMenuButtonAccessible = 1 << 11,
-    eMenuPopupAccessible = 1 << 12,
-    eRootAccessible = 1 << 13,
-    eTextLeafAccessible = 1 << 14
+    eImageAccessible = 1 << 10,
+    eListControlAccessible = 1 << 11,
+    eMenuButtonAccessible = 1 << 12,
+    eMenuPopupAccessible = 1 << 13,
+    eRootAccessible = 1 << 14,
+    eTextLeafAccessible = 1 << 15
   };
 
   //////////////////////////////////////////////////////////////////////////////

accessible/src/html/nsHTMLImageAccessible.h

@@ -92,5 +92,14 @@ private:
   bool IsValidLongDescIndex(PRUint8 aIndex);
 };
 
+////////////////////////////////////////////////////////////////////////////////
+// nsAccessible downcasting method
+inline nsHTMLImageAccessible*
+nsAccessible::AsImage()
+{
+  return IsImageAccessible() ?
+    static_cast<nsHTMLImageAccessible*>(this) : nsnull;
+}
+
 #endif