Bug 566298 - don't use nsIAccessible::GetNextSibling() to iterate children, r=davidb, sr=neil

accessible/src/atk/nsAccessibleWrap.cpp

@@ -943,36 +943,26 @@ getIndexInParentCB(AtkObject *aAtkObj)
         return -1;
     }
 
-    nsCOMPtr<nsIAccessible> parent;
-    accWrap->GetParent(getter_AddRefs(parent));
+    nsAccessible *parent = accWrap->GetParent();
     if (!parent) {
         return -1; // No parent
     }
 
-    nsCOMPtr<nsIAccessible> sibling;
-    parent->GetFirstChild(getter_AddRefs(sibling));
-    if (!sibling) {
-        return -1;  // Error, parent has no children
-    }
-
     PRInt32 currentIndex = 0;
 
-    while (sibling != static_cast<nsIAccessible*>(accWrap)) {
-      NS_ASSERTION(sibling, "Never ran into the same child that we started from");
-
-      if (!sibling) {
-          return -1;
+    PRInt32 childCount = parent->GetChildCount();
+    for (PRInt32 idx = 0; idx < childCount; idx++) {
+      nsAccessible *sibling = parent->GetChildAt(idx);
+      if (sibling == accWrap) {
+          return currentIndex;
       }
+
       if (nsAccUtils::IsEmbeddedObject(sibling)) {
-        ++ currentIndex;
+          ++ currentIndex;
       }
-
-      nsCOMPtr<nsIAccessible> tempAccessible;
-      sibling->GetNextSibling(getter_AddRefs(tempAccessible));
-      sibling.swap(tempAccessible);
     }
 
-    return currentIndex;
+    return -1;
 }
 
 static void TranslateStates(PRUint32 aState, const AtkStateMap *aStateMap,

accessible/src/base/nsARIAGridAccessible.cpp

@@ -1130,15 +1130,14 @@ nsARIAGridCellAccessible::GetAttributesInternal(nsIPersistentProperties *aAttrib
 
   // Expose "table-cell-index" attribute.
 
-  nsCOMPtr<nsIAccessible> thisRow;
-  GetParent(getter_AddRefs(thisRow));
+  nsAccessible *thisRow = GetParent();
   if (nsAccUtils::Role(thisRow) != nsIAccessibleRole::ROLE_ROW)
     return NS_OK;
 
   PRInt32 colIdx = 0, colCount = 0;
-  nsCOMPtr<nsIAccessible> child, nextChild;
-  thisRow->GetFirstChild(getter_AddRefs(child));
-  while (child) {
+  PRInt32 childCount = thisRow->GetChildCount();
+  for (PRInt32 childIdx = 0; childIdx < childCount; childIdx++) {
+    nsAccessible *child = thisRow->GetChildAt(childIdx);
     if (child == this)
       colIdx = colCount;
 
@@ -1147,25 +1146,22 @@ nsARIAGridCellAccessible::GetAttributesInternal(nsIPersistentProperties *aAttrib
         role == nsIAccessibleRole::ROLE_ROWHEADER ||
         role == nsIAccessibleRole::ROLE_COLUMNHEADER)
       colCount++;
-
-    child->GetNextSibling(getter_AddRefs(nextChild));
-    child.swap(nextChild);
   }
 
-  nsCOMPtr<nsIAccessible> table;
-  thisRow->GetParent(getter_AddRefs(table));
+  nsAccessible *table = thisRow->GetParent();
   if (nsAccUtils::Role(table) != nsIAccessibleRole::ROLE_TABLE &&
       nsAccUtils::Role(table) != nsIAccessibleRole::ROLE_TREE_TABLE)
     return NS_OK;
 
   PRInt32 rowIdx = 0;
-  table->GetFirstChild(getter_AddRefs(child));
-  while (child && child != thisRow) {
+  childCount = table->GetChildCount();
+  for (PRInt32 childIdx = 0; childIdx < childCount; childIdx++) {
+    nsAccessible *child = table->GetChildAt(childIdx);
+    if (child == thisRow)
+      break;
+
     if (nsAccUtils::Role(child) == nsIAccessibleRole::ROLE_ROW)
       rowIdx++;
-
-    child->GetNextSibling(getter_AddRefs(nextChild));
-    child.swap(nextChild);
   }
 
   PRInt32 idx = rowIdx * colCount + colIdx;

accessible/src/base/nsAccUtils.cpp

@@ -789,31 +789,29 @@ nsAccUtils::GetLiveAttrValue(PRUint32 aRule, nsAString& aValue)
 #ifdef DEBUG_A11Y
 
 PRBool
-nsAccUtils::IsTextInterfaceSupportCorrect(nsIAccessible *aAccessible)
+nsAccUtils::IsTextInterfaceSupportCorrect(nsAccessible *aAccessible)
 {
   PRBool foundText = PR_FALSE;
   
-  nsCOMPtr<nsIAccessibleDocument> accDoc = do_QueryInterface(aAccessible);
+  nsCOMPtr<nsIAccessibleDocument> accDoc = do_QueryObject(aAccessible);
   if (accDoc) {
     // Don't test for accessible docs, it makes us create accessibles too
     // early and fire mutation events before we need to
     return PR_TRUE;
   }
 
-  nsCOMPtr<nsIAccessible> child, nextSibling;
-  aAccessible->GetFirstChild(getter_AddRefs(child));
-  while (child) {
+  PRInt32 childCount = aAccessible->GetChildCount();
+  for (PRint32 childIdx = 0; childIdx < childCount; childIdx++) {
+    nsAccessible *child = GetChildAt(childIdx);
     if (IsText(child)) {
       foundText = PR_TRUE;
       break;
     }
-    child->GetNextSibling(getter_AddRefs(nextSibling));
-    child.swap(nextSibling);
   }
 
   if (foundText) {
     // found text child node
-    nsCOMPtr<nsIAccessibleText> text = do_QueryInterface(aAccessible);
+    nsCOMPtr<nsIAccessibleText> text = do_QueryObject(aAccessible);
     if (!text)
       return PR_FALSE;
   }

accessible/src/base/nsAccUtils.h

@@ -324,7 +324,7 @@ public:
    * Detect whether the given accessible object implements nsIAccessibleText,
    * when it is text or has text child node.
    */
-  static PRBool IsTextInterfaceSupportCorrect(nsIAccessible *aAccessible);
+  static PRBool IsTextInterfaceSupportCorrect(nsAccessible *aAccessible);
 #endif
 
   /**

accessible/src/base/nsDocAccessible.cpp

@@ -1803,9 +1803,8 @@ void nsDocAccessible::RefreshNodes(nsIDOMNode *aStartNode)
     // created.
     if (accessible->GetCachedFirstChild()) {
       nsCOMPtr<nsIArray> children;
-      // use GetChildren() to fetch children at one time, instead of using
-      // GetNextSibling(), because after we shutdown the first child,
-      // mNextSibling will be set null.
+      // use GetChildren() to fetch all children at once, because after shutdown
+      // the child references are cleared.
       accessible->GetChildren(getter_AddRefs(children));
       PRUint32 childCount =0;
       if (children)

accessible/src/base/nsTextEquivUtils.cpp

@@ -236,16 +236,14 @@ nsresult
 nsTextEquivUtils::AppendFromAccessibleChildren(nsIAccessible *aAccessible,
                                                nsAString *aString)
 {
-  nsCOMPtr<nsIAccessible> accChild, accNextChild;
-  aAccessible->GetFirstChild(getter_AddRefs(accChild));
-
   nsresult rv = NS_OK_NO_NAME_CLAUSE_HANDLED;
-  while (accChild) {
-    rv = AppendFromAccessible(accChild, aString);
-    NS_ENSURE_SUCCESS(rv, rv);
 
-    accChild->GetNextSibling(getter_AddRefs(accNextChild));
-    accChild.swap(accNextChild);
+  nsRefPtr<nsAccessible> accessible(do_QueryObject(aAccessible));
+  PRInt32 childCount = accessible->GetChildCount();
+  for (PRInt32 childIdx = 0; childIdx < childCount; childIdx++) {
+    nsAccessible *child = accessible->GetChildAt(childIdx);
+    rv = AppendFromAccessible(child, aString);
+    NS_ENSURE_SUCCESS(rv, rv);
   }
 
   return rv;

accessible/src/msaa/nsAccessibleWrap.cpp

@@ -390,26 +390,21 @@ __try {
 
       PRUint32 currentRole = nsAccUtils::Role(xpAccessible);
       if (currentRole == nsIAccessibleRole::ROLE_OUTLINEITEM) {
-        nsCOMPtr<nsIAccessible> child;
-        xpAccessible->GetFirstChild(getter_AddRefs(child));
-        while (child) {
+        PRInt32 childCount = xpAccessible->GetChildCount();
+        for (PRInt32 childIdx = 0; childIdx < childCount; childIdx++) {
+          nsAccessible *child = xpAccessible->GetChildAt(childIdx);
           currentRole = nsAccUtils::Role(child);
           if (currentRole == nsIAccessibleRole::ROLE_GROUPING) {
-            nsCOMPtr<nsIAccessible> groupChild;
-            child->GetFirstChild(getter_AddRefs(groupChild));
-            while (groupChild) {
+            PRInt32 groupChildCount = child->GetChildCount();
+            for (PRInt32 groupChildIdx = 0; groupChildIdx < groupChildCount;
+                 groupChildIdx++) {
+              nsAccessible *groupChild = child->GetChildAt(groupChildIdx);
               currentRole = nsAccUtils::Role(groupChild);
               numChildren +=
                 (currentRole == nsIAccessibleRole::ROLE_OUTLINEITEM);
-              nsCOMPtr<nsIAccessible> nextGroupChild;
-              groupChild->GetNextSibling(getter_AddRefs(nextGroupChild));
-              groupChild.swap(nextGroupChild);
             }
             break;
           }
-          nsCOMPtr<nsIAccessible> nextChild;
-          child->GetNextSibling(getter_AddRefs(nextChild));
-          child.swap(nextChild);
         }
       }
 

accessible/src/xforms/nsXFormsAccessible.cpp

@@ -553,39 +553,32 @@ already_AddRefed<nsIDOMNode>
 nsXFormsSelectableAccessible::GetItemByIndex(PRInt32 *aIndex,
                                              nsIAccessible *aAccessible)
 {
-  nsCOMPtr<nsIAccessible> accessible(aAccessible ? aAccessible : this);
+  nsRefPtr<nsAccessible> accessible(do_QueryObject(aAccessible));
+  if (!accessible)
+    accessible = this;
 
-  nsCOMPtr<nsIAccessible> curAccChild;
-  accessible->GetFirstChild(getter_AddRefs(curAccChild));
+  PRInt32 childCount = accessible->GetChildCount();
+  for (PRInt32 childIdx = 0; childIdx < childCount; childIdx++) {
+    nsAccessible *child = accessible->GetChildAt(childIdx);
 
-  while (curAccChild) {
-    nsCOMPtr<nsIAccessNode> curAccNodeChild(do_QueryInterface(curAccChild));
-    if (curAccNodeChild) {
-      nsCOMPtr<nsIDOMNode> curChildNode;
-      curAccNodeChild->GetDOMNode(getter_AddRefs(curChildNode));
-      nsCOMPtr<nsIContent> curChildContent(do_QueryInterface(curChildNode));
-      if (curChildContent) {
-        nsCOMPtr<nsINodeInfo> nodeInfo = curChildContent->NodeInfo();
-        if (nodeInfo->NamespaceEquals(NS_LITERAL_STRING(NS_NAMESPACE_XFORMS))) {
-          if (nodeInfo->Equals(nsAccessibilityAtoms::item)) {
-            if (!*aIndex) {
-              nsIDOMNode *itemNode = nsnull;
-              curChildNode.swap(itemNode);
-              return itemNode;
-            }
-            --*aIndex;
-          } else if (nodeInfo->Equals(nsAccessibilityAtoms::choices)) {
-            nsIDOMNode *itemNode = GetItemByIndex(aIndex, curAccChild).get();
-            if (itemNode)
-              return itemNode;
-          }
-        }
+    nsCOMPtr<nsIDOMNode> childNode(child->GetDOMNode());
+    nsCOMPtr<nsIContent> childContent(do_QueryInterface(childNode));
+    if (!childContent)
+      continue;
+
+    nsINodeInfo *nodeInfo = childContent->NodeInfo();
+    if (nodeInfo->NamespaceEquals(NS_LITERAL_STRING(NS_NAMESPACE_XFORMS))) {
+      if (nodeInfo->Equals(nsAccessibilityAtoms::item)) {
+        if (!*aIndex)
+          return childNode.forget();
+
+        --*aIndex;
+      } else if (nodeInfo->Equals(nsAccessibilityAtoms::choices)) {
+        nsIDOMNode *itemNode = GetItemByIndex(aIndex, child).get();
+        if (itemNode)
+          return itemNode;
       }
     }
-
-    nsCOMPtr<nsIAccessible> nextAccChild;
-    curAccChild->GetNextSibling(getter_AddRefs(nextAccChild));
-    curAccChild.swap(nextAccChild);
   }
 
   return nsnull;

accessible/src/xul/nsXULListboxAccessible.cpp

@@ -1149,25 +1149,23 @@ nsXULListCellAccessible::GetColumnHeaderCells(nsIArray **aHeaderCells)
   NS_ENSURE_STATE(table); // we expect to be in a listbox (table)
 
   // Get column header cell from XUL listhead.
-  nsCOMPtr<nsIAccessible> tableAcc(do_QueryInterface(table));
+  nsAccessible *list = nsnull;
 
-  nsCOMPtr<nsIAccessible> list, nextChild;
-  tableAcc->GetFirstChild(getter_AddRefs(list));
-  while (list) {
-    if (nsAccUtils::Role(list) == nsIAccessibleRole::ROLE_LIST)
+  nsRefPtr<nsAccessible> tableAcc(do_QueryObject(table));
+  PRInt32 tableChildCount = tableAcc->GetChildCount();
+  for (PRInt32 childIdx = 0; childIdx < tableChildCount; childIdx++) {
+    nsAccessible *child = tableAcc->GetChildAt(childIdx);
+    if (nsAccUtils::Role(child) == nsIAccessibleRole::ROLE_LIST) {
+      list = child;
       break;
-
-    list->GetNextSibling(getter_AddRefs(nextChild));
-    nextChild.swap(list);
+    }
   }
 
   if (list) {
     PRInt32 colIdx = -1;
     GetColumnIndex(&colIdx);
 
-    nsCOMPtr<nsIAccessible> headerCell;
-    list->GetChildAt(colIdx, getter_AddRefs(headerCell));
-
+    nsIAccessible *headerCell = list->GetChildAt(colIdx);
     if (headerCell) {
       nsresult rv = NS_OK;
       nsCOMPtr<nsIMutableArray> headerCells =