(Concept patch) Simplify WTF::HashTable::add() return value for size and performance

Source/wtf/HashTable.h

Index: Source/wtf/HashTable.h
diff --git a/Source/wtf/HashTable.h b/Source/wtf/HashTable.h
index e5f01acd4227d5939f1ec53e7e8c245a71bdcc06..0d55681e684b3aaa50e48be368e64d2bf5f5ba06 100644
--- a/Source/wtf/HashTable.h
+++ b/Source/wtf/HashTable.h
@@ -206,9 +206,9 @@ namespace WTF {
         template<typename T, typename U> static void translate(T& location, const U&, const T& value) { location = value; }
     };
 
-    template<typename IteratorType> struct HashTableAddResult {
-        HashTableAddResult(IteratorType iter, bool isNewEntry) : iterator(iter), isNewEntry(isNewEntry) { }
-        IteratorType iterator;
+    template<typename ValueType> struct HashTableAddResult {
+        HashTableAddResult(ValueType* iterator, bool isNewEntry) : iterator(iterator), isNewEntry(isNewEntry) { }

[Erik Corry, 2014/02/04 14:27:15]

If this is no longer an iterator, should it be called 'iterator'?

[eseidel, 2014/02/05 22:17:20]

No. :)  But presumably Daniel did this to minimize changes?  I would call this
value or addedValue or something.

+        ValueType* iterator;
         bool isNewEntry;
     };
 
@@ -231,7 +231,7 @@ namespace WTF {
         typedef Value ValueType;
         typedef typename Traits::PeekInType ValuePeekInType;
         typedef IdentityHashTranslator<HashFunctions> IdentityTranslatorType;
-        typedef HashTableAddResult<iterator> AddResult;
+        typedef HashTableAddResult<ValueType> AddResult;
 
 #if DUMP_HASHTABLE_STATS_PER_TABLE
         struct Stats {
@@ -688,7 +688,7 @@ namespace WTF {
                     break;
 
                 if (HashTranslator::equal(Extractor::extract(*entry), key))
-                    return AddResult(makeKnownGoodIterator(entry), false);
+                    return AddResult(entry, false);
 
                 if (isDeletedBucket(*entry))
                     deletedEntry = entry;
@@ -699,7 +699,7 @@ namespace WTF {
                 if (isDeletedBucket(*entry))
                     deletedEntry = entry;
                 else if (HashTranslator::equal(Extractor::extract(*entry), key))
-                    return AddResult(makeKnownGoodIterator(entry), false);
+                    return AddResult(entry, false);
             }
 #if DUMP_HASHTABLE_STATS
             ++probeCount;
@@ -732,12 +732,14 @@ namespace WTF {
             // follow a pivot entry and return the new position.
             typename WTF::RemoveReference<KeyPassInType>::Type enteredKey = Extractor::extract(*entry);
             expand();
-            AddResult result(find(enteredKey), true);
-            ASSERT(result.iterator != end());
+            iterator findResult = find(enteredKey);
+            ASSERT(findResult != end());
+            ValueType* resultValue = findResult.get();
+            AddResult result(resultValue, true);
             return result;
         }
 
-        return AddResult(makeKnownGoodIterator(entry), true);
+        return AddResult(entry, true);
     }
 
     template<typename Key, typename Value, typename Extractor, typename HashFunctions, typename Traits, typename KeyTraits, typename Allocator>
@@ -754,7 +756,7 @@ namespace WTF {
         unsigned h = lookupResult.second;
 
         if (found)
-            return AddResult(makeKnownGoodIterator(entry), false);
+            return AddResult(entry, false);
 
         if (isDeletedBucket(*entry)) {
             initializeBucket(*entry);
@@ -769,12 +771,14 @@ namespace WTF {
             // follow a pivot entry and return the new position.
             typename WTF::RemoveReference<KeyPassInType>::Type enteredKey = Extractor::extract(*entry);
             expand();
-            AddResult result(find(enteredKey), true);
-            ASSERT(result.iterator != end());
+            iterator findResult = find(enteredKey);
+            ASSERT(findResult != end());
+            ValueType* resultValue = findResult.get();
+            AddResult result(resultValue, true);
             return result;
         }
 
-        return AddResult(makeKnownGoodIterator(entry), true);
+        return AddResult(entry, true);
     }
 
     template<typename Key, typename Value, typename Extractor, typename HashFunctions, typename Traits, typename KeyTraits, typename Allocator>