From 0ae60a4b0461a4b40c4ca944f15eab72568c5729 Mon Sep 17 00:00:00 2001
From: Neil Deakin <neil@mozilla.com>
Date: Tue, 15 Dec 2009 11:07:50 -0500
Subject: [PATCH] Bug 321177, use recursive algorithm to find member variable,
 r=jonas

---
 .../templates/src/nsXULTemplateBuilder.cpp    | 73 +++++++------------
 .../xul/templates/src/nsXULTemplateBuilder.h  |  3 +-
 2 files changed, 26 insertions(+), 50 deletions(-)

diff --git a/content/xul/templates/src/nsXULTemplateBuilder.cpp b/content/xul/templates/src/nsXULTemplateBuilder.cpp
index a94aeffae09b..8f9ead6e0506 100644
--- a/content/xul/templates/src/nsXULTemplateBuilder.cpp
+++ b/content/xul/templates/src/nsXULTemplateBuilder.cpp
@@ -1870,9 +1870,11 @@ nsXULTemplateBuilder::CompileTemplate(nsIContent* aTemplate,
                                               getter_AddRefs(action));
 
             if (action){
-                nsCOMPtr<nsIAtom> memberVariable;
-                DetermineMemberVariable(action, getter_AddRefs(memberVariable));
-                if (! memberVariable) continue;
+                nsCOMPtr<nsIAtom> memberVariable = mMemberVariable;
+                if (!memberVariable) {
+                    memberVariable = DetermineMemberVariable(action);
+                    if (!memberVariable) continue;
+                }
 
                 if (hasQuery) {
                     nsCOMPtr<nsIAtom> tag;
@@ -1994,9 +1996,11 @@ nsXULTemplateBuilder::CompileTemplate(nsIContent* aTemplate,
             if (tag)
                 aQuerySet->SetTag(tag);
 
-            nsCOMPtr<nsIAtom> memberVariable;
-            DetermineMemberVariable(rulenode, getter_AddRefs(memberVariable));
-            if (! memberVariable) continue;
+            nsCOMPtr<nsIAtom> memberVariable = mMemberVariable;
+            if (!memberVariable) {
+                memberVariable = DetermineMemberVariable(rulenode);
+                if (!memberVariable) continue;
+            }
 
             nsCOMPtr<nsIDOMNode> query(do_QueryInterface(aQuerySet->mQueryNode));
 
@@ -2077,53 +2081,26 @@ nsXULTemplateBuilder::CompileExtendedQuery(nsIContent* aRuleElement,
     return NS_OK;
 }
 
-nsresult
-nsXULTemplateBuilder::DetermineMemberVariable(nsIContent* aActionElement,
-                                              nsIAtom** aMemberVariable)
+already_AddRefed<nsIAtom>
+nsXULTemplateBuilder::DetermineMemberVariable(nsIContent* aElement)
 {
-    // If the member variable hasn't already been specified, then
-    // grovel over <action> to find it. We'll use the first one
-    // that we find in a breadth-first search.
+    // recursively iterate over the children looking for an element
+    // with uri="?..."
+    for (nsINode::ChildIterator iter(aElement); !iter.IsDone(); iter.Next()) {
+        nsAutoString uri;
+        nsIContent *child = iter;
+        child->GetAttr(kNameSpaceID_None, nsGkAtoms::uri, uri);
+        if (!uri.IsEmpty() && uri[0] == PRUnichar('?')) {
+            return NS_NewAtom(uri);
+        }
 
-    if (mMemberVariable) {
-        *aMemberVariable = mMemberVariable;
-        NS_IF_ADDREF(*aMemberVariable);
-    }
-    else {
-        *aMemberVariable = nsnull;
-
-        nsCOMArray<nsIContent> unvisited;
-
-        if (!unvisited.AppendObject(aActionElement))
-            return NS_ERROR_OUT_OF_MEMORY;
-
-        while (unvisited.Count()) {
-            nsIContent* next = unvisited[0];
-            unvisited.RemoveObjectAt(0);
-
-            nsAutoString uri;
-            next->GetAttr(kNameSpaceID_None, nsGkAtoms::uri, uri);
-
-            if (!uri.IsEmpty() && uri[0] == PRUnichar('?')) {
-                // Found it.
-                *aMemberVariable = NS_NewAtom(uri);
-                break;
-            }
-
-            // otherwise, append the children to the unvisited list: this
-            // results in a breadth-first search.
-            PRUint32 count = next->GetChildCount();
-
-            for (PRUint32 i = 0; i < count; ++i) {
-                nsIContent *child = next->GetChildAt(i);
-
-                if (!unvisited.AppendObject(child))
-                    return NS_ERROR_OUT_OF_MEMORY;
-            }
+        nsCOMPtr<nsIAtom> result = DetermineMemberVariable(child);
+        if (result) {
+            return result.forget();
         }
     }
 
-    return NS_OK;
+    return nsnull;
 }
 
 void
diff --git a/content/xul/templates/src/nsXULTemplateBuilder.h b/content/xul/templates/src/nsXULTemplateBuilder.h
index 6fd941ac241c..138b5e0f6f7b 100644
--- a/content/xul/templates/src/nsXULTemplateBuilder.h
+++ b/content/xul/templates/src/nsXULTemplateBuilder.h
@@ -212,8 +212,7 @@ public:
      * Determine the member variable from inside an action body. It will be
      * the value of the uri attribute on a node.
      */
-    nsresult
-    DetermineMemberVariable(nsIContent* aActionElement, nsIAtom** aMemberVariable);
+    already_AddRefed<nsIAtom> DetermineMemberVariable(nsIContent* aElement);
 
     /**
      * Compile a simple query. A simple query is one that doesn't have a