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27 #ifndef WTF_PassOwnPtr_h
28 #define WTF_PassOwnPtr_h
30 #include "wtf/NullPtr.h"
31 #include "wtf/OwnPtrCommon.h"
35 template<typename T> class OwnPtr;
36 template<typename T> class PassOwnPtr;
37 template<typename T> PassOwnPtr<T> adoptPtr(T*);
38 template<typename T> PassOwnPtr<T[]> adoptArrayPtr(T*);
40 template<typename T> class PassOwnPtr {
42 typedef typename RemoveExtent<T>::Type ValueType;
43 typedef ValueType* PtrType;
45 PassOwnPtr() : m_ptr(0) { }
46 PassOwnPtr(std::nullptr_t) : m_ptr(0) { }
48 // It somewhat breaks the type system to allow transfer of ownership out of
49 // a const PassOwnPtr. However, it makes it much easier to work with PassOwnPtr
50 // temporaries, and we don't have a need to use real const PassOwnPtrs anyway.
51 PassOwnPtr(const PassOwnPtr& o) : m_ptr(o.leakPtr()) { }
52 template<typename U> PassOwnPtr(const PassOwnPtr<U>&, EnsurePtrConvertibleArgDecl(U, T));
54 ~PassOwnPtr() { OwnedPtrDeleter<T>::deletePtr(m_ptr); }
56 PtrType get() const { return m_ptr; }
58 PtrType leakPtr() const WARN_UNUSED_RETURN;
60 ValueType& operator*() const { ASSERT(m_ptr); return *m_ptr; }
61 PtrType operator->() const { ASSERT(m_ptr); return m_ptr; }
63 bool operator!() const { return !m_ptr; }
65 // This conversion operator allows implicit conversion to bool but not to other integer types.
66 typedef PtrType PassOwnPtr::*UnspecifiedBoolType;
67 operator UnspecifiedBoolType() const { return m_ptr ? &PassOwnPtr::m_ptr : 0; }
69 template<typename U> friend PassOwnPtr<U> adoptPtr(U*);
70 template<typename U> friend PassOwnPtr<U[]> adoptArrayPtr(U*);
71 template<typename U> friend class OwnPtr;
74 explicit PassOwnPtr(PtrType ptr) : m_ptr(ptr) { }
76 PassOwnPtr& operator=(const PassOwnPtr&) { COMPILE_ASSERT(!sizeof(T*), PassOwnPtr_should_never_be_assigned_to); return *this; }
78 // We should never have two OwnPtrs for the same underlying object (otherwise we'll get
79 // double-destruction), so these equality operators should never be needed.
80 template<typename U> bool operator==(const PassOwnPtr<U>&) const { COMPILE_ASSERT(!sizeof(U*), OwnPtrs_should_never_be_equal); return false; }
81 template<typename U> bool operator!=(const PassOwnPtr<U>&) const { COMPILE_ASSERT(!sizeof(U*), OwnPtrs_should_never_be_equal); return false; }
82 template<typename U> bool operator==(const OwnPtr<U>&) const { COMPILE_ASSERT(!sizeof(U*), OwnPtrs_should_never_be_equal); return false; }
83 template<typename U> bool operator!=(const OwnPtr<U>&) const { COMPILE_ASSERT(!sizeof(U*), OwnPtrs_should_never_be_equal); return false; }
85 mutable PtrType m_ptr;
88 template<typename T> template<typename U> inline PassOwnPtr<T>::PassOwnPtr(const PassOwnPtr<U>& o, EnsurePtrConvertibleArgDefn(U, T))
91 COMPILE_ASSERT(!IsArray<T>::value, Pointers_to_array_must_never_be_converted);
94 template<typename T> inline typename PassOwnPtr<T>::PtrType PassOwnPtr<T>::leakPtr() const
101 template<typename T, typename U> inline bool operator==(const PassOwnPtr<T>& a, U* b)
106 template<typename T, typename U> inline bool operator==(T* a, const PassOwnPtr<U>& b)
111 template<typename T, typename U> inline bool operator!=(const PassOwnPtr<T>& a, U* b)
116 template<typename T, typename U> inline bool operator!=(T* a, const PassOwnPtr<U>& b)
121 template<typename T> inline PassOwnPtr<T> adoptPtr(T* ptr)
123 return PassOwnPtr<T>(ptr);
126 template<typename T> inline PassOwnPtr<T[]> adoptArrayPtr(T* ptr)
128 return PassOwnPtr<T[]>(ptr);
131 template<typename T, typename U> inline PassOwnPtr<T> static_pointer_cast(const PassOwnPtr<U>& p)
133 COMPILE_ASSERT(!IsArray<T>::value, Pointers_to_array_must_never_be_converted);
134 return adoptPtr(static_cast<T*>(p.leakPtr()));
137 template<typename T> inline T* getPtr(const PassOwnPtr<T>& p)
144 using WTF::PassOwnPtr;
146 using WTF::adoptArrayPtr;
147 using WTF::static_pointer_cast;
149 #endif // WTF_PassOwnPtr_h