bug 427841 - TreeViewChanged event fired on a particular tree table more than once breaks that table's AT-SPI hierarchy, patch by Alexander Surkov <surkov.alexander@gmail.com>, r=evan.yan

accessible/public/nsIAccessibleTreeCache.idl

@@ -47,7 +47,7 @@ interface nsIAccessible;
  *
  * @status UNDER_REVIEW
  */
-[uuid(7e0f50b0-6444-4372-b00f-4ce81c6b058a)]
+[uuid(1dde5c3b-bede-43d1-aabf-dabc461113bd)]
 interface nsIAccessibleTreeCache : nsISupports
 {
   /**
@@ -82,6 +82,12 @@ interface nsIAccessibleTreeCache : nsISupports
    */
   void treeViewInvalidated(in long aStartRow, in long aEndRow,
                            in long aStartCol, in long aEndCol);
+
+  /**
+   * Invalidates children created for previous tree view.
+   */
+  void treeViewChanged();
+
 };
 
 [uuid(b71532f9-53b2-4647-a5b2-1c5f57e9aed6)]

accessible/src/atk/nsAccessibleWrap.cpp

@@ -1102,12 +1102,18 @@ nsAccessibleWrap::FireAccessibleEvent(nsIAccessibleEvent *aEvent)
     nsresult rv = nsAccessible::FireAccessibleEvent(aEvent);
     NS_ENSURE_SUCCESS(rv, rv);
 
+    return FirePlatformEvent(aEvent);
+}
+
+nsresult
+nsAccessibleWrap::FirePlatformEvent(nsIAccessibleEvent *aEvent)
+{
     nsCOMPtr<nsIAccessible> accessible;
     aEvent->GetAccessible(getter_AddRefs(accessible));
     NS_ENSURE_TRUE(accessible, NS_ERROR_FAILURE);
 
     PRUint32 type = 0;
-    rv = aEvent->GetEventType(&type);
+    nsresult rv = aEvent->GetEventType(&type);
     NS_ENSURE_SUCCESS(rv, rv);
 
     AtkObject *atkObj = nsAccessibleWrap::GetAtkObject(accessible);

accessible/src/atk/nsAccessibleWrap.h

@@ -116,6 +116,8 @@ public:
     }
 
 protected:
+    virtual nsresult FirePlatformEvent(nsIAccessibleEvent *aEvent);
+
     nsresult FireAtkStateChangeEvent(nsIAccessibleEvent *aEvent,
                                      AtkObject *aObject);
     nsresult FireAtkTextChangedEvent(nsIAccessibleEvent *aEvent,

accessible/src/base/nsAccessible.h

@@ -246,6 +246,16 @@ protected:
    */
   nsresult GetAttrValue(nsIAtom *aAriaProperty, double *aValue);
 
+  /**
+   * Fires platform accessible event. It's notification method only. It does
+   * change nothing on Gecko side. Mostly you should use
+   * nsIAccessible::FireAccessibleEvent excepting special cases like we have
+   * in xul:tree accessible to lie to AT. Must be overridden in wrap classes.
+   *
+   * @param aEvent  the accessible event to fire.
+   */
+  virtual nsresult FirePlatformEvent(nsIAccessibleEvent *aEvent) = 0;
+
   // Data Members
   nsCOMPtr<nsIAccessible> mParent;
   nsIAccessible *mFirstChild, *mNextSibling;

accessible/src/base/nsRootAccessible.cpp

@@ -643,18 +643,6 @@ nsresult nsRootAccessible::HandleEventWithTarget(nsIDOMEvent* aEvent,
     return NS_OK;
   }
 
-#ifdef MOZ_XUL
-  if (eventType.EqualsLiteral("TreeViewChanged")) { // Always asynch, always from user input
-    if (!isTree)
-      return NS_OK;
-
-    nsCOMPtr<nsIContent> treeContent = do_QueryInterface(aTargetNode);
-    nsAccEvent::PrepareForEvent(aTargetNode, PR_TRUE);
-    return accService->InvalidateSubtreeFor(eventShell, treeContent,
-                                            nsIAccessibleEvent::EVENT_DOM_SIGNIFICANT_CHANGE);
-  }
-#endif
-
   if (eventType.EqualsLiteral("popuphiding")) {
     // If accessible focus was on or inside popup that closes,
     // then restore it to true current focus.
@@ -678,11 +666,22 @@ nsresult nsRootAccessible::HandleEventWithTarget(nsIDOMEvent* aEvent,
     return NS_OK;
 
 #ifdef MOZ_XUL
-  if (eventType.EqualsLiteral("TreeRowCountChanged"))
+  if (isTree) {
-    return HandleTreeRowCountChangedEvent(aEvent, accessible, localName);
+    nsCOMPtr<nsIAccessibleTreeCache> treeAcc(do_QueryInterface(accessible));
-  
+    NS_ASSERTION(treeAcc,
-  if (eventType.EqualsLiteral("TreeInvalidated"))
+                 "Accessible for xul:tree doesn't implement nsIAccessibleTreeCache interface.");
-    return HandleTreeInvalidatedEvent(aEvent, accessible, localName);
+
+    if (treeAcc) {
+      if (eventType.EqualsLiteral("TreeViewChanged"))
+        return treeAcc->TreeViewChanged();
+
+      if (eventType.EqualsLiteral("TreeRowCountChanged"))
+        return HandleTreeRowCountChangedEvent(aEvent, treeAcc);
+      
+      if (eventType.EqualsLiteral("TreeInvalidated"))
+        return HandleTreeInvalidatedEvent(aEvent, treeAcc);
+    }
+  }
 #endif
 
   if (eventType.EqualsLiteral("RadioStateChange")) {
@@ -1095,12 +1094,8 @@ NS_IMETHODIMP nsRootAccessible::FireDocLoadEvents(PRUint32 aEventType)
 
 nsresult
 nsRootAccessible::HandleTreeRowCountChangedEvent(nsIDOMEvent *aEvent,
-                                                 nsIAccessible *aAccessible,
+                                                 nsIAccessibleTreeCache *aAccessible)
-                                                 const nsAString& aTargetName)
 {
-  if (!aTargetName.EqualsLiteral("tree"))
-    return NS_OK;
-
   nsCOMPtr<nsIDOMDataContainerEvent> dataEvent(do_QueryInterface(aEvent));
   if (!dataEvent)
     return NS_OK;
@@ -1121,20 +1116,13 @@ nsRootAccessible::HandleTreeRowCountChangedEvent(nsIDOMEvent *aEvent,
   indexVariant->GetAsInt32(&index);
   countVariant->GetAsInt32(&count);
 
-  nsCOMPtr<nsIAccessibleTreeCache> treeAccCache(do_QueryInterface(aAccessible));
+  return aAccessible->InvalidateCache(index, count);
-  NS_ENSURE_STATE(treeAccCache);
-
-  return treeAccCache->InvalidateCache(index, count);
 }
 
 nsresult
 nsRootAccessible::HandleTreeInvalidatedEvent(nsIDOMEvent *aEvent,
-                                             nsIAccessible *aAccessible,
+                                             nsIAccessibleTreeCache *aAccessible)
-                                             const nsAString& aTargetName)
 {
-  if (!aTargetName.EqualsLiteral("tree"))
-    return NS_OK;
-
   nsCOMPtr<nsIDOMDataContainerEvent> dataEvent(do_QueryInterface(aEvent));
   if (!dataEvent)
     return NS_OK;
@@ -1165,9 +1153,6 @@ nsRootAccessible::HandleTreeInvalidatedEvent(nsIDOMEvent *aEvent,
   if (endColVariant)
     endColVariant->GetAsInt32(&endCol);
 
-  nsCOMPtr<nsIAccessibleTreeCache> treeAcc(do_QueryInterface(aAccessible));
+  return aAccessible->TreeViewInvalidated(startRow, endRow, startCol, endCol);
-  NS_ENSURE_STATE(treeAcc);
-
-  return treeAcc->TreeViewInvalidated(startRow, endRow, startCol, endCol);
 }
 

accessible/src/base/nsRootAccessible.h

@@ -38,9 +38,13 @@
 #ifndef _nsRootAccessible_H_
 #define _nsRootAccessible_H_
 
+#include "nsCaretAccessible.h"
 #include "nsDocAccessibleWrap.h"
-#include "nsHashtable.h"
+
 #include "nsIAccessibleDocument.h"
+#include "nsIAccessibleTreeCache.h"
+
+#include "nsHashtable.h"
 #include "nsCaretAccessible.h"
 #include "nsIDocument.h"
 #include "nsIDOMFocusListener.h"
@@ -124,15 +128,13 @@ class nsRootAccessible : public nsDocAccessibleWrap,
      * Handles 'TreeRowCountChanged' event. Used in HandleEventWithTarget().
      */
     nsresult HandleTreeRowCountChangedEvent(nsIDOMEvent *aEvent,
-                                            nsIAccessible *aAccessible,
+                                            nsIAccessibleTreeCache *aAccessible);
-                                            const nsAString& aTargetName);
 
     /**
      * Handles 'TreeInvalidated' event. Used in HandleEventWithTarget().
      */
     nsresult HandleTreeInvalidatedEvent(nsIDOMEvent *aEvent,
-                                        nsIAccessible *aAccessible,
+                                        nsIAccessibleTreeCache *aAccessible);
-                                        const nsAString& aTargetName);
 
 #ifdef MOZ_XUL
     PRUint32 GetChromeFlags();

accessible/src/mac/nsAccessibleWrap.h

@@ -96,7 +96,9 @@ class nsAccessibleWrap : public nsAccessible
     virtual already_AddRefed<nsIAccessible> GetUnignoredParent();
     
   protected:
-    
+
+    virtual nsresult FirePlatformEvent(nsIAccessibleEvent *aEvent);
+
     PRBool AncestorIsFlat() {
       // we don't create a native object if we're child of a "flat" accessible; for example, on OS X buttons 
       // shouldn't have any children, because that makes the OS confused. 

accessible/src/mac/nsAccessibleWrap.mm

@@ -169,8 +169,18 @@ nsAccessibleWrap::FireAccessibleEvent(nsIAccessibleEvent *aEvent)
   nsresult rv = nsAccessible::FireAccessibleEvent(aEvent);
   NS_ENSURE_SUCCESS(rv, rv);
 
+  return FirePlatformEvent(aEvent);
+
+  NS_OBJC_END_TRY_ABORT_BLOCK_NSRESULT;
+}
+
+nsresult
+nsAccessibleWrap::FirePlatformEvent(nsIAccessibleEvent *aEvent)
+{
+  NS_OBJC_BEGIN_TRY_ABORT_BLOCK_NSRESULT;
+
   PRUint32 eventType;
-  rv = aEvent->GetEventType(&eventType);
+  nsresult rv = aEvent->GetEventType(&eventType);
   NS_ENSURE_SUCCESS(rv, rv);
 
   // ignore everything but focus-changed and value-changed events for now.

accessible/src/msaa/nsAccessibleWrap.cpp

@@ -1690,6 +1690,12 @@ nsAccessibleWrap::FireAccessibleEvent(nsIAccessibleEvent *aEvent)
   nsresult rv = nsAccessible::FireAccessibleEvent(aEvent);
   NS_ENSURE_SUCCESS(rv, rv);
 
+  return FirePlatformEvent(aEvent);
+}
+
+nsresult
+nsAccessibleWrap::FirePlatformEvent(nsIAccessibleEvent *aEvent)
+{
   PRUint32 eventType = 0;
   aEvent->GetEventType(&eventType);
 

accessible/src/msaa/nsAccessibleWrap.h

@@ -313,6 +313,8 @@ class nsAccessibleWrap : public nsAccessible,
   static IDispatch *NativeAccessible(nsIAccessible *aXPAccessible);
 
 protected:
+  virtual nsresult FirePlatformEvent(nsIAccessibleEvent *aEvent);
+
   // mEnumVARIANTPosition not the current accessible's position, but a "cursor" of 
   // where we are in the current list of children, with respect to
   // nsIEnumVariant::Reset(), Skip() and Next().

accessible/src/xul/nsXULTreeAccessible.cpp

@@ -636,7 +636,7 @@ nsXULTreeAccessible::TreeViewInvalidated(PRInt32 aStartRow, PRInt32 aEndRow,
 {
   NS_ENSURE_TRUE(mTree && mTreeView, NS_ERROR_FAILURE);
 
-  PRInt32 endRow = aEndRow, endCol = aEndCol;
+  PRInt32 endRow = aEndRow;
 
   nsresult rv;
   if (endRow == -1) {
@@ -652,6 +652,8 @@ nsXULTreeAccessible::TreeViewInvalidated(PRInt32 aStartRow, PRInt32 aEndRow,
   NS_ENSURE_STATE(treeColumns);
 
 #ifdef MOZ_ACCESSIBILITY_ATK
+  PRInt32 endCol = aEndCol;
+
   if (endCol == -1) {
     PRInt32 colCount = 0;
     rv = treeColumns->GetCount(&colCount);
@@ -705,6 +707,37 @@ nsXULTreeAccessible::TreeViewInvalidated(PRInt32 aStartRow, PRInt32 aEndRow,
   return NS_OK;
 }
 
+// void nsIAccessibleTreeCache::treeViewChanged();
+NS_IMETHODIMP
+nsXULTreeAccessible::TreeViewChanged()
+{
+  if (!mTree)
+    return NS_ERROR_FAILURE;
+
+  // Fire only notification destroy/create events on accessible tree to lie to
+  // AT because it should be expensive to fire destroy events for each tree item
+  // in cache.
+  nsCOMPtr<nsIAccessibleEvent> eventDestroy =
+    new nsAccEvent(nsIAccessibleEvent::EVENT_DOM_DESTROY,
+                   this, PR_FALSE);
+  NS_ENSURE_TRUE(eventDestroy, NS_ERROR_OUT_OF_MEMORY);
+
+  nsresult rv = FirePlatformEvent(eventDestroy);
+
+  ClearCache(*mAccessNodeCache);
+
+  mTree->GetView(getter_AddRefs(mTreeView));
+
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsCOMPtr<nsIAccessibleEvent> eventCreate =
+    new nsAccEvent(nsIAccessibleEvent::EVENT_DOM_CREATE,
+                   this, PR_FALSE);
+  NS_ENSURE_TRUE(eventCreate, NS_ERROR_OUT_OF_MEMORY);
+
+  return FirePlatformEvent(eventCreate);
+}
+
 nsresult nsXULTreeAccessible::GetColumnCount(nsITreeBoxObject* aBoxObject, PRInt32* aCount)
 {
   NS_ENSURE_TRUE(aBoxObject, NS_ERROR_FAILURE);
@@ -714,7 +747,8 @@ nsresult nsXULTreeAccessible::GetColumnCount(nsITreeBoxObject* aBoxObject, PRInt
   return treeColumns->GetCount(aCount);
 }
 
-// ---------- nsXULTreeitemAccessible ---------- 
+////////////////////////////////////////////////////////////////////////////////
+// nsXULTreeitemAccessible
 
 nsXULTreeitemAccessible::nsXULTreeitemAccessible(nsIAccessible *aParent, nsIDOMNode *aDOMNode, nsIWeakReference *aShell, PRInt32 aRow, nsITreeColumn* aColumn)
   : nsLeafAccessible(aDOMNode, aShell)