2 * Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010 Apple Inc. All rights reserved.
4 * This library is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU Library General Public
6 * License as published by the Free Software Foundation; either
7 * version 2 of the License, or (at your option) any later version.
9 * This library is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * Library General Public License for more details.
14 * You should have received a copy of the GNU Library General Public License
15 * along with this library; see the file COPYING.LIB. If not, write to
16 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
17 * Boston, MA 02110-1301, USA.
21 #ifndef WTF_PassRefPtr_h
22 #define WTF_PassRefPtr_h
24 #include "AlwaysInline.h"
29 template<typename T> class RefPtr;
30 template<typename T> class PassRefPtr;
31 template<typename T> PassRefPtr<T> adoptRef(T*);
33 inline void adopted(const void*) { }
37 #define REF_DEREF_INLINE ALWAYS_INLINE
39 // Using ALWAYS_INLINE broke the Qt build. This may be a GCC bug.
40 // See https://bugs.webkit.org/show_bug.cgi?id=37253 for details.
41 #define REF_DEREF_INLINE inline
44 // No inlining for WINSCW compiler to prevent the compiler agressively resolving
45 // T::ref() and T::deref(), which will fail compiling when PassRefPtr<T> is used as
46 // a class member or function arguments before T is defined.
47 #define REF_DEREF_INLINE
50 template<typename T> REF_DEREF_INLINE void refIfNotNull(T* ptr)
56 template<typename T> REF_DEREF_INLINE void derefIfNotNull(T* ptr)
62 #undef REF_DEREF_INLINE
64 template<typename T> class PassRefPtr {
66 PassRefPtr() : m_ptr(0) { }
67 PassRefPtr(T* ptr) : m_ptr(ptr) { refIfNotNull(ptr); }
68 // It somewhat breaks the type system to allow transfer of ownership out of
69 // a const PassRefPtr. However, it makes it much easier to work with PassRefPtr
70 // temporaries, and we don't have a need to use real const PassRefPtrs anyway.
71 PassRefPtr(const PassRefPtr& o) : m_ptr(o.leakRef()) { }
72 template<typename U> PassRefPtr(const PassRefPtr<U>& o) : m_ptr(o.leakRef()) { }
74 ALWAYS_INLINE ~PassRefPtr() { derefIfNotNull(m_ptr); }
76 template<typename U> PassRefPtr(const RefPtr<U>&);
78 T* get() const { return m_ptr; }
80 T* leakRef() const WARN_UNUSED_RETURN;
82 T& operator*() const { return *m_ptr; }
83 T* operator->() const { return m_ptr; }
85 bool operator!() const { return !m_ptr; }
87 // This conversion operator allows implicit conversion to bool but not to other integer types.
88 typedef T* (PassRefPtr::*UnspecifiedBoolType);
89 operator UnspecifiedBoolType() const { return m_ptr ? &PassRefPtr::m_ptr : 0; }
91 PassRefPtr& operator=(const PassRefPtr&) { COMPILE_ASSERT(!sizeof(T*), PassRefPtr_should_never_be_assigned_to); return *this; }
93 friend PassRefPtr adoptRef<T>(T*);
95 // FIXME: Remove releaseRef once we change all callers to call leakRef instead.
96 T* releaseRef() const WARN_UNUSED_RETURN { return leakRef(); }
99 // adopting constructor
100 PassRefPtr(T* ptr, bool) : m_ptr(ptr) { }
105 // NonNullPassRefPtr: Optimized for passing non-null pointers. A NonNullPassRefPtr
106 // begins life non-null, and can only become null through a call to leakRef()
109 // FIXME: NonNullPassRefPtr could just inherit from PassRefPtr. However,
110 // if we use inheritance, GCC's optimizer fails to realize that destruction
111 // of a released NonNullPassRefPtr is a no-op. So, for now, just copy the
112 // most important code from PassRefPtr.
113 template<typename T> class NonNullPassRefPtr {
115 NonNullPassRefPtr(T* ptr)
122 template<typename U> NonNullPassRefPtr(const RefPtr<U>& o)
129 NonNullPassRefPtr(const NonNullPassRefPtr& o)
135 template<typename U> NonNullPassRefPtr(const NonNullPassRefPtr<U>& o)
141 template<typename U> NonNullPassRefPtr(const PassRefPtr<U>& o)
147 ALWAYS_INLINE ~NonNullPassRefPtr() { derefIfNotNull(m_ptr); }
149 T* get() const { return m_ptr; }
151 T* leakRef() const WARN_UNUSED_RETURN { T* tmp = m_ptr; m_ptr = 0; return tmp; }
153 T& operator*() const { return *m_ptr; }
154 T* operator->() const { return m_ptr; }
156 NonNullPassRefPtr& operator=(const NonNullPassRefPtr&) { COMPILE_ASSERT(!sizeof(T*), NonNullPassRefPtr_should_never_be_assigned_to); return *this; }
158 // FIXME: Remove releaseRef once we change all callers to call leakRef instead.
159 T* releaseRef() const WARN_UNUSED_RETURN { return leakRef(); }
165 template<typename T> template<typename U> inline PassRefPtr<T>::PassRefPtr(const RefPtr<U>& o)
172 template<typename T> inline T* PassRefPtr<T>::leakRef() const
179 template<typename T, typename U> inline bool operator==(const PassRefPtr<T>& a, const PassRefPtr<U>& b)
181 return a.get() == b.get();
184 template<typename T, typename U> inline bool operator==(const PassRefPtr<T>& a, const RefPtr<U>& b)
186 return a.get() == b.get();
189 template<typename T, typename U> inline bool operator==(const RefPtr<T>& a, const PassRefPtr<U>& b)
191 return a.get() == b.get();
194 template<typename T, typename U> inline bool operator==(const PassRefPtr<T>& a, U* b)
199 template<typename T, typename U> inline bool operator==(T* a, const PassRefPtr<U>& b)
204 template<typename T, typename U> inline bool operator!=(const PassRefPtr<T>& a, const PassRefPtr<U>& b)
206 return a.get() != b.get();
209 template<typename T, typename U> inline bool operator!=(const PassRefPtr<T>& a, const RefPtr<U>& b)
211 return a.get() != b.get();
214 template<typename T, typename U> inline bool operator!=(const RefPtr<T>& a, const PassRefPtr<U>& b)
216 return a.get() != b.get();
219 template<typename T, typename U> inline bool operator!=(const PassRefPtr<T>& a, U* b)
224 template<typename T, typename U> inline bool operator!=(T* a, const PassRefPtr<U>& b)
229 template<typename T> inline PassRefPtr<T> adoptRef(T* p)
232 return PassRefPtr<T>(p, true);
235 template<typename T, typename U> inline PassRefPtr<T> static_pointer_cast(const PassRefPtr<U>& p)
237 return adoptRef(static_cast<T*>(p.leakRef()));
240 template<typename T, typename U> inline PassRefPtr<T> const_pointer_cast(const PassRefPtr<U>& p)
242 return adoptRef(const_cast<T*>(p.leakRef()));
245 template<typename T> inline T* getPtr(const PassRefPtr<T>& p)
252 using WTF::PassRefPtr;
253 using WTF::NonNullPassRefPtr;
255 using WTF::static_pointer_cast;
256 using WTF::const_pointer_cast;
258 #endif // WTF_PassRefPtr_h