Bug 518950 - FindNextTextNode in mozInlineSpellWordUtil.cpp is slow, r=bz

extensions/spellcheck/src/mozInlineSpellWordUtil.cpp

@@ -50,6 +50,7 @@
 #include "nsIDOMHTMLBRElement.h"
 #include "nsUnicharUtilCIID.h"
 #include "nsServiceManagerUtils.h"
+#include "nsIContent.h"
 
 // IsIgnorableCharacter
 //
@@ -177,39 +178,36 @@ FindNextTextNode(nsIDOMNode* aNode, PRInt32 aOffset, nsIDOMNode* aRoot)
   NS_PRECONDITION(aNode, "Null starting node?");
   NS_ASSERTION(!IsTextNode(aNode), "FindNextTextNode should start with a non-text node");
 
-  nsIDOMNode* checkNode;
+  nsCOMPtr<nsINode> node = do_QueryInterface(aNode);
+  nsCOMPtr<nsIDOMNode> checkNode;
   // Need to start at the aOffset'th child
-  nsCOMPtr<nsIDOMNode> child;
-  aNode->GetFirstChild(getter_AddRefs(child));
-  while (child && aOffset > 0) {
-    nsCOMPtr<nsIDOMNode> next;
-    child->GetNextSibling(getter_AddRefs(next));
-    child.swap(next);
-    --aOffset;
-  }
+  nsIContent* child = node->GetChildAt(aOffset);
+
   if (child) {
-    checkNode = child;
+    checkNode = do_QueryInterface(child);
   } else {
     // aOffset was beyond the end of the child list. 
     // goto next node in a preorder DOM traversal.
-    nsCOMPtr<nsIDOMNode> next;
-    aNode->GetNextSibling(getter_AddRefs(next));
-    while (!next) {
-      // Go up
-      aNode->GetParentNode(getter_AddRefs(next));
-      if (next == aRoot || !next) {
-        return nsnull;
+    nsINode* next = node->GetSibling(1);
+    if (!next) {
+      nsCOMPtr<nsINode> root = do_QueryInterface(aRoot);
+      while (!next) {
+        // Go up
+        next = node->GetNodeParent();
+        if (next == root || !next) {
+          return nsnull;
+        }
+        node = next;
+        next = node->GetSibling(1);
       }
-      aNode = next;
-      aNode->GetNextSibling(getter_AddRefs(next));
     }
-    checkNode = next;
+    checkNode = do_QueryInterface(next);
   }
   
   while (checkNode && !IsTextNode(checkNode)) {
     checkNode = FindNextNode(checkNode, aRoot);
   }
-  return checkNode;
+  return checkNode.get();
 }
 
 // mozInlineSpellWordUtil::SetEnd