From ad0d549d4cc13433f77c1ac8f0ab379c83d93f28 Mon Sep 17 00:00:00 2001
From: Simon Hausmann <simon.hausmann@nokia.com>
Date: Fri, 24 Feb 2012 16:36:50 +0100
Subject: Imported WebKit commit bb52bf3c0119e8a128cd93afe5572413a8617de9
 (http://svn.webkit.org/repository/webkit/trunk@108790)

---
 Source/JavaScriptCore/heap/Weak.h | 100 ++++++++++++++++++--------------------
 1 file changed, 46 insertions(+), 54 deletions(-)

(limited to 'Source/JavaScriptCore/heap/Weak.h')

diff --git a/Source/JavaScriptCore/heap/Weak.h b/Source/JavaScriptCore/heap/Weak.h
index f0c028d71..96fe1b58c 100644
--- a/Source/JavaScriptCore/heap/Weak.h
+++ b/Source/JavaScriptCore/heap/Weak.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2009 Apple Inc. All rights reserved.
+ * Copyright (C) 2009, 2012 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ -30,11 +30,14 @@
 #include "Handle.h"
 #include "HandleHeap.h"
 #include "JSGlobalData.h"
+#include "PassWeak.h"
 
 namespace JSC {
 
 // A weakly referenced handle that becomes 0 when the value it points to is garbage collected.
 template <typename T> class Weak : public Handle<T> {
+    WTF_MAKE_NONCOPYABLE(Weak);
+
     using Handle<T>::slot;
     using Handle<T>::setSlot;
 
@@ -46,11 +49,18 @@ public:
     {
     }
 
-    Weak(JSGlobalData& globalData, ExternalType value = ExternalType(), WeakHandleOwner* weakOwner = 0, void* context = 0)
+    Weak(std::nullptr_t)
+        : Handle<T>()
+    {
+    }
+
+    Weak(JSGlobalData& globalData, ExternalType externalType = ExternalType(), WeakHandleOwner* weakOwner = 0, void* context = 0)
         : Handle<T>(globalData.heap.handleHeap()->allocate())
     {
         HandleHeap::heapFor(slot())->makeWeak(slot(), weakOwner, context);
-        set(value);
+        JSValue value = HandleTypes<T>::toJSValue(externalType);
+        HandleHeap::heapFor(slot())->writeBarrier(slot(), value);
+        *slot() = value;
     }
 
     enum AdoptTag { Adopt };
@@ -59,23 +69,7 @@ public:
     {
         validateCell(get());
     }
-    
-    Weak(const Weak& other)
-        : Handle<T>()
-    {
-        if (!other.slot())
-            return;
-        setSlot(HandleHeap::heapFor(other.slot())->copyWeak(other.slot()));
-    }
 
-    template <typename U> Weak(const Weak<U>& other)
-        : Handle<T>()
-    {
-        if (!other.slot())
-            return;
-        setSlot(HandleHeap::heapFor(other.slot())->copyWeak(other.slot()));
-    }
-    
     enum HashTableDeletedValueTag { HashTableDeletedValue };
     bool isHashTableDeletedValue() const { return slot() == hashTableDeletedValue(); }
     Weak(HashTableDeletedValueTag)
@@ -83,6 +77,11 @@ public:
     {
     }
 
+    template<typename U> Weak(const PassWeak<U>& other)
+        : Handle<T>(other.leakHandle())
+    {
+    }
+
     ~Weak()
     {
         clear();
@@ -93,8 +92,12 @@ public:
         Handle<T>::swap(other);
     }
 
+    Weak& operator=(const PassWeak<T>&);
+
     ExternalType get() const { return  HandleTypes<T>::getFromSlot(slot()); }
     
+    PassWeak<T> release() { PassWeak<T> tmp = adoptWeak<T>(slot()); setSlot(0); return tmp; }
+
     void clear()
     {
         if (!slot())
@@ -103,32 +106,6 @@ public:
         setSlot(0);
     }
     
-    void set(JSGlobalData& globalData, ExternalType value, WeakHandleOwner* weakOwner = 0, void* context = 0)
-    {
-        if (!slot()) {
-            setSlot(globalData.heap.handleHeap()->allocate());
-            HandleHeap::heapFor(slot())->makeWeak(slot(), weakOwner, context);
-        }
-        ASSERT(HandleHeap::heapFor(slot())->hasWeakOwner(slot(), weakOwner));
-        set(value);
-    }
-
-    template <typename U> Weak& operator=(const Weak<U>& other)
-    {
-        clear();
-        if (other.slot())
-            setSlot(HandleHeap::heapFor(other.slot())->copyWeak(other.slot()));
-        return *this;
-    }
-
-    Weak& operator=(const Weak& other)
-    {
-        clear();
-        if (other.slot())
-            setSlot(HandleHeap::heapFor(other.slot())->copyWeak(other.slot()));
-        return *this;
-    }
-    
     HandleSlot leakHandle()
     {
         ASSERT(HandleHeap::heapFor(slot())->hasFinalizer(slot()));
@@ -139,14 +116,6 @@ public:
 
 private:
     static HandleSlot hashTableDeletedValue() { return reinterpret_cast<HandleSlot>(-1); }
-
-    void set(ExternalType externalType)
-    {
-        ASSERT(slot());
-        JSValue value = HandleTypes<T>::toJSValue(externalType);
-        HandleHeap::heapFor(slot())->writeBarrier(slot(), value);
-        *slot() = value;
-    }
 };
 
 template<class T> inline void swap(Weak<T>& a, Weak<T>& b)
@@ -154,6 +123,13 @@ template<class T> inline void swap(Weak<T>& a, Weak<T>& b)
     a.swap(b);
 }
 
+template<typename T> inline Weak<T>& Weak<T>::operator=(const PassWeak<T>& o)
+{
+    clear();
+    setSlot(o.leakHandle());
+    return *this;
+}
+
 } // namespace JSC
 
 namespace WTF {
@@ -162,7 +138,23 @@ template<typename T> struct VectorTraits<JSC::Weak<T> > : SimpleClassVectorTrait
     static const bool canCompareWithMemcmp = false;
 };
 
-template<typename P> struct HashTraits<JSC::Weak<P> > : SimpleClassHashTraits<JSC::Weak<P> > { };
+template<typename T> struct HashTraits<JSC::Weak<T> > : SimpleClassHashTraits<JSC::Weak<T> > {
+    typedef JSC::Weak<T> StorageType;
+
+    typedef std::nullptr_t EmptyValueType;
+    static EmptyValueType emptyValue() { return nullptr; }
+
+    typedef JSC::PassWeak<T> PassInType;
+    static void store(PassInType value, StorageType& storage) { storage = value; }
+
+    typedef JSC::PassWeak<T> PassOutType;
+    static PassOutType passOut(StorageType& value) { return value.release(); }
+    static PassOutType passOut(EmptyValueType) { return PassOutType(); }
+
+    typedef typename StorageType::ExternalType PeekType;
+    static PeekType peek(const StorageType& value) { return value.get(); }
+    static PeekType peek(EmptyValueType) { return PeekType(); }
+};
 
 }
 
-- 
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