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29 #include "Assertions.h"
31 #include "HandleHeap.h"
32 #include "JSGlobalData.h"
36 // A weakly referenced handle that becomes 0 when the value it points to is garbage collected.
37 template <typename T> class Weak : public Handle<T> {
38 using Handle<T>::slot;
39 using Handle<T>::setSlot;
42 typedef typename Handle<T>::ExternalType ExternalType;
49 Weak(JSGlobalData& globalData, ExternalType value = ExternalType(), WeakHandleOwner* weakOwner = 0, void* context = 0)
50 : Handle<T>(globalData.allocateGlobalHandle())
52 HandleHeap::heapFor(slot())->makeWeak(slot(), weakOwner, context);
56 enum AdoptTag { Adopt };
57 template<typename U> Weak(AdoptTag, Handle<U> handle)
58 : Handle<T>(handle.slot())
63 Weak(const Weak& other)
68 setSlot(HandleHeap::heapFor(other.slot())->copyWeak(other.slot()));
71 template <typename U> Weak(const Weak<U>& other)
76 setSlot(HandleHeap::heapFor(other.slot())->copyWeak(other.slot()));
79 enum HashTableDeletedValueTag { HashTableDeletedValue };
80 bool isHashTableDeletedValue() const { return slot() == hashTableDeletedValue(); }
81 Weak(HashTableDeletedValueTag)
82 : Handle<T>(hashTableDeletedValue())
91 void swap(Weak& other)
93 Handle<T>::swap(other);
96 ExternalType get() const { return HandleTypes<T>::getFromSlot(slot()); }
102 HandleHeap::heapFor(slot())->deallocate(slot());
106 void set(JSGlobalData& globalData, ExternalType value, WeakHandleOwner* weakOwner = 0, void* context = 0)
109 setSlot(globalData.allocateGlobalHandle());
110 HandleHeap::heapFor(slot())->makeWeak(slot(), weakOwner, context);
112 ASSERT(HandleHeap::heapFor(slot())->hasWeakOwner(slot(), weakOwner));
116 template <typename U> Weak& operator=(const Weak<U>& other)
120 setSlot(HandleHeap::heapFor(other.slot())->copyWeak(other.slot()));
124 Weak& operator=(const Weak& other)
128 setSlot(HandleHeap::heapFor(other.slot())->copyWeak(other.slot()));
132 HandleSlot leakHandle()
134 ASSERT(HandleHeap::heapFor(slot())->hasFinalizer(slot()));
135 HandleSlot result = slot();
141 static HandleSlot hashTableDeletedValue() { return reinterpret_cast<HandleSlot>(-1); }
143 void set(ExternalType externalType)
146 JSValue value = HandleTypes<T>::toJSValue(externalType);
147 ASSERT(!value || !value.isCell() || Heap::isMarked(value.asCell()));
148 HandleHeap::heapFor(slot())->writeBarrier(slot(), value);
153 template<class T> inline void swap(Weak<T>& a, Weak<T>& b)
162 template<typename T> struct VectorTraits<JSC::Weak<T> > : SimpleClassVectorTraits {
163 static const bool canCompareWithMemcmp = false;
166 template<typename P> struct HashTraits<JSC::Weak<P> > : SimpleClassHashTraits<JSC::Weak<P> > { };