Oilpan: make Supplementable tracing more regular.

Source/platform/Supplementable.h

 /*
  * Copyright (C) 2012 Google, Inc. All Rights Reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 82 matching lines @@
 
 template<typename T, bool isGarbageCollected>
 class SupplementableBase;
 
 template<typename T, bool isGarbageCollected>
 struct SupplementableTraits;
 
 template<typename T>
 struct SupplementableTraits<T, true> {
     typedef RawPtr<SupplementBase<T, true> > SupplementArgumentType;
-    typedef HeapHashMap<const char*, Member<SupplementBase<T, true> >, PtrHash<const char*> > SupplementMap;
 };
 
 template<typename T>
 struct SupplementableTraits<T, false> {
     typedef PassOwnPtr<SupplementBase<T, false> > SupplementArgumentType;
-    typedef HashMap<const char*, OwnPtr<SupplementBase<T, false> >, PtrHash<const char*> > SupplementMap;
 };
 
 template<bool>
 class SupplementTracing;
 
 template<>
 class SupplementTracing<true> : public GarbageCollectedMixin { };
 
 template<>
 class SupplementTracing<false> {
 public:
     virtual ~SupplementTracing() { }
+    // FIXME: Oilpan: this trace() method is only provided to minimize
+    // the use of ENABLE(OILPAN) for Supplements deriving from the
+    // transition type WillBeHeapSupplement<>.
+    //
+    // When that transition type is removed (or its use is substantially
+    // reduced), remove this dummy trace method also.
     virtual void trace(Visitor*) { }
 };
 
 template<typename T, bool isGarbageCollected = false>
 class SupplementBase : public SupplementTracing<isGarbageCollected> {
 public:
 #if ENABLE(SECURITY_ASSERT)
     virtual bool isRefCountedWrapper() const { return false; }
 #endif
 
     static void provideTo(SupplementableBase<T, isGarbageCollected>& host, const char* key, typename SupplementableTraits<T, isGarbageCollected>::SupplementArgumentType supplement)
     {
         host.provideSupplement(key, supplement);
     }
 
     static SupplementBase<T, isGarbageCollected>* from(SupplementableBase<T, isGarbageCollected>& host, const char* key)
     {
         return host.requireSupplement(key);
     }
 
     static SupplementBase<T, isGarbageCollected>* from(SupplementableBase<T, isGarbageCollected>* host, const char* key)
     {
         return host ? host->requireSupplement(key) : 0;
     }
 };
 
+template<typename T, bool isGarbageCollected>
+class SupplementableTracing;
+
+template<typename T>
+class SupplementableTracing<T, true> : public GarbageCollectedMixin {
+public:
+    virtual void trace(Visitor* visitor)
+    {
+        visitor->trace(m_supplements);
+    }
+
+protected:
+    typedef HeapHashMap<const char*, Member<SupplementBase<T, true> >, PtrHash<const char*> > SupplementMap;
+    SupplementMap m_supplements;
+};
+
+template<typename T>
+class SupplementableTracing<T, false> {
+protected:
+    typedef HashMap<const char*, OwnPtr<SupplementBase<T, false> >, PtrHash<const char*> > SupplementMap;
+    SupplementMap m_supplements;
+};
+
 // Helper class for implementing Supplementable and HeapSupplementable.
 template<typename T, bool isGarbageCollected = false>
-class SupplementableBase {
+class SupplementableBase : public SupplementableTracing<T, isGarbageCollected> {
 public:
     void provideSupplement(const char* key, typename SupplementableTraits<T, isGarbageCollected>::SupplementArgumentType supplement)
     {
         ASSERT(m_threadId == currentThread());
         ASSERT(!this->m_supplements.get(key));
         this->m_supplements.set(key, supplement);
     }
 
     void removeSupplement(const char* key)
     {
         ASSERT(m_threadId == currentThread());
         this->m_supplements.remove(key);
     }
 
     SupplementBase<T, isGarbageCollected>* requireSupplement(const char* key)
     {
         ASSERT(m_threadId == currentThread());
         return this->m_supplements.get(key);
     }
 
     void reattachThread()
     {
 #if ENABLE(ASSERT)
         m_threadId = currentThread();
 #endif
     }
 
-    // We have a trace method in the SupplementableBase class to ensure we have
-    // the vtable at the first word of the object. However we don't trace the
-    // m_supplements here, but in the partially specialized template subclasses
-    // since we only want to trace it for garbage collected classes.
-    virtual void trace(Visitor*) { }
-
-    // FIXME: Oilpan: Make private and remove this ignore once PersistentHeapSupplementable is removed again.
-protected:
-    GC_PLUGIN_IGNORE("")
-    typename SupplementableTraits<T, isGarbageCollected>::SupplementMap m_supplements;
-
 #if ENABLE(ASSERT)
 protected:
     SupplementableBase() : m_threadId(currentThread()) { }
 
 private:
     ThreadIdentifier m_threadId;
 #endif
 };
 
-// This class is used to make an on-heap class supplementable. Its supplements
-// must be HeapSupplement.
 template<typename T>
 class HeapSupplement : public SupplementBase<T, true> { };
 
-// FIXME: Oilpan: Move GarbageCollectedMixin to SupplementableBase<T, true> once PersistentHeapSupplementable is removed again.
 template<typename T>
-class GC_PLUGIN_IGNORE("http://crbug.com/395036") HeapSupplementable : public SupplementableBase<T, true>, public GarbageCollectedMixin {
-public:
-    virtual void trace(Visitor* visitor) OVERRIDE
-    {
-        visitor->trace(this->m_supplements);
-        SupplementableBase<T, true>::trace(visitor);
-    }
-};
+class HeapSupplementable : public SupplementableBase<T, true> { };
 
 template<typename T>
 class Supplement : public SupplementBase<T, false> { };
 
-// This class is used to make an off-heap class supplementable with off-heap
-// supplements (Supplement).
 template<typename T>
-class GC_PLUGIN_IGNORE("http://crbug.com/395036") Supplementable : public SupplementableBase<T, false> {
-public:
-    virtual void trace(Visitor* visitor)
-    {
-        // No tracing of off-heap supplements. We should not have any Supplementable
-        // object on the heap.
-        COMPILE_ASSERT(!IsGarbageCollectedType<T>::value, GarbageCollectedObjectMustBeHeapSupplementable);
-        SupplementableBase<T, false>::trace(visitor);
-    }
-};
+class Supplementable : public SupplementableBase<T, false> { };
 
 template<typename T>
 struct ThreadingTrait<SupplementBase<T, true> > {
     static const ThreadAffinity Affinity = ThreadingTrait<T>::Affinity;
 };
 
 template<typename T>
 struct ThreadingTrait<SupplementableBase<T, true> > {
     static const ThreadAffinity Affinity = ThreadingTrait<T>::Affinity;
 };
 
 } // namespace blink
 
 #endif // Supplementable_h