| /* |
| * Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010 Apple Inc. All rights reserved. |
| * |
| * This library is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU Library General Public |
| * License as published by the Free Software Foundation; either |
| * version 2 of the License, or (at your option) any later version. |
| * |
| * This library is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| * Library General Public License for more details. |
| * |
| * You should have received a copy of the GNU Library General Public License |
| * along with this library; see the file COPYING.LIB. If not, write to |
| * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, |
| * Boston, MA 02110-1301, USA. |
| * |
| */ |
| |
| #ifndef WTF_PassRefPtr_h |
| #define WTF_PassRefPtr_h |
| |
| #include "wtf/Assertions.h" |
| #include "wtf/NullPtr.h" |
| #include "wtf/RawPtr.h" |
| #include "wtf/TypeTraits.h" |
| |
| namespace WTF { |
| |
| template <typename T> class RefPtr; |
| template <typename T> class PassRefPtr; |
| template <typename T> PassRefPtr<T> adoptRef(T*); |
| |
| inline void adopted(const void*) {} |
| |
| // requireAdoption() is not overloaded for WTF::RefCounted, which has a built-in |
| // assumption that adoption is required. requireAdoption() is for bootstrapping |
| // alternate reference count classes that are compatible with ReftPtr/PassRefPtr |
| // but cannot have adoption checks enabled by default, such as skia's |
| // SkRefCnt. The purpose of requireAdoption() is to enable adoption checks only |
| // once it is known that the object will be used with RefPtr/PassRefPtr. |
| inline void requireAdoption(const void*) {} |
| |
| template <typename T> ALWAYS_INLINE void refIfNotNull(T* ptr) |
| { |
| if (LIKELY(ptr != 0)) { |
| requireAdoption(ptr); |
| ptr->ref(); |
| } |
| } |
| |
| template <typename T> ALWAYS_INLINE void derefIfNotNull(T* ptr) |
| { |
| if (LIKELY(ptr != 0)) |
| ptr->deref(); |
| } |
| |
| template <typename T> class PassRefPtr { |
| public: |
| PassRefPtr() : m_ptr(nullptr) {} |
| PassRefPtr(std::nullptr_t) : m_ptr(nullptr) {} |
| PassRefPtr(T* ptr) : m_ptr(ptr) { refIfNotNull(ptr); } |
| template <typename U> PassRefPtr(const RawPtr<U>& ptr, EnsurePtrConvertibleArgDecl(U, T)) : m_ptr(ptr.get()) { refIfNotNull(m_ptr); } |
| explicit PassRefPtr(T& ptr) : m_ptr(&ptr) { m_ptr->ref(); } |
| // It somewhat breaks the type system to allow transfer of ownership out of |
| // a const PassRefPtr. However, it makes it much easier to work with |
| // PassRefPtr temporaries, and we don't have a need to use real const |
| // PassRefPtrs anyway. |
| PassRefPtr(const PassRefPtr& o) : m_ptr(o.leakRef()) {} |
| template <typename U> PassRefPtr(const PassRefPtr<U>& o, EnsurePtrConvertibleArgDecl(U, T)) : m_ptr(o.leakRef()) {} |
| |
| ALWAYS_INLINE ~PassRefPtr() { derefIfNotNull(m_ptr); } |
| |
| template <typename U> PassRefPtr(const RefPtr<U>&, EnsurePtrConvertibleArgDecl(U, T)); |
| |
| T* get() const { return m_ptr; } |
| |
| T* leakRef() const WARN_UNUSED_RETURN; |
| |
| T& operator*() const { return *m_ptr; } |
| T* operator->() const { return m_ptr; } |
| |
| bool operator!() const { return !m_ptr; } |
| |
| // This conversion operator allows implicit conversion to bool but not to |
| // other integer types. |
| typedef T* (PassRefPtr::*UnspecifiedBoolType); |
| operator UnspecifiedBoolType() const { return m_ptr ? &PassRefPtr::m_ptr : 0; } |
| |
| friend PassRefPtr adoptRef<T>(T*); |
| |
| private: |
| enum AdoptRefTag { AdoptRef }; |
| PassRefPtr(T* ptr, AdoptRefTag) : m_ptr(ptr) {} |
| |
| PassRefPtr& operator=(const PassRefPtr&) |
| { |
| static_assert(!sizeof(T*), "PassRefPtr should never be assigned to"); |
| return *this; |
| } |
| |
| mutable T* m_ptr; |
| }; |
| |
| template <typename T> |
| template <typename U> inline PassRefPtr<T>::PassRefPtr(const RefPtr<U>& o, EnsurePtrConvertibleArgDefn(U, T)) |
| : m_ptr(o.get()) |
| { |
| T* ptr = m_ptr; |
| refIfNotNull(ptr); |
| } |
| |
| template <typename T> inline T* PassRefPtr<T>::leakRef() const |
| { |
| T* ptr = m_ptr; |
| m_ptr = nullptr; |
| return ptr; |
| } |
| |
| template <typename T, typename U> inline bool operator==(const PassRefPtr<T>& a, const PassRefPtr<U>& b) |
| { |
| return a.get() == b.get(); |
| } |
| |
| template <typename T, typename U> inline bool operator==(const PassRefPtr<T>& a, const RefPtr<U>& b) |
| { |
| return a.get() == b.get(); |
| } |
| |
| template <typename T, typename U> inline bool operator==(const RefPtr<T>& a, const PassRefPtr<U>& b) |
| { |
| return a.get() == b.get(); |
| } |
| |
| template <typename T, typename U> inline bool operator==(const PassRefPtr<T>& a, U* b) |
| { |
| return a.get() == b; |
| } |
| |
| template <typename T, typename U> inline bool operator==(T* a, const PassRefPtr<U>& b) |
| { |
| return a == b.get(); |
| } |
| |
| template <typename T, typename U> inline bool operator==(const PassRefPtr<T>& a, const RawPtr<U>& b) |
| { |
| return a.get() == b.get(); |
| } |
| |
| template <typename T, typename U> inline bool operator==(const RawPtr<T>& a, const PassRefPtr<U>& b) |
| { |
| return a.get() == b.get(); |
| } |
| |
| template <typename T, typename U> inline bool operator!=(const PassRefPtr<T>& a, const PassRefPtr<U>& b) |
| { |
| return a.get() != b.get(); |
| } |
| |
| template <typename T, typename U> inline bool operator!=(const PassRefPtr<T>& a, const RefPtr<U>& b) |
| { |
| return a.get() != b.get(); |
| } |
| |
| template <typename T, typename U> inline bool operator!=(const RefPtr<T>& a, const PassRefPtr<U>& b) |
| { |
| return a.get() != b.get(); |
| } |
| |
| template <typename T, typename U> inline bool operator!=(const PassRefPtr<T>& a, U* b) |
| { |
| return a.get() != b; |
| } |
| |
| template <typename T, typename U> inline bool operator!=(T* a, const PassRefPtr<U>& b) |
| { |
| return a != b.get(); |
| } |
| |
| template <typename T, typename U> inline bool operator!=(const PassRefPtr<T>& a, const RawPtr<U>& b) |
| { |
| return a.get() != b.get(); |
| } |
| |
| template <typename T, typename U> inline bool operator!=(const RawPtr<T>& a, const PassRefPtr<U>& b) |
| { |
| return a.get() != b.get(); |
| } |
| |
| template <typename T> PassRefPtr<T> adoptRef(T* p) |
| { |
| adopted(p); |
| return PassRefPtr<T>(p, PassRefPtr<T>::AdoptRef); |
| } |
| |
| template <typename T, typename U> inline PassRefPtr<T> static_pointer_cast(const PassRefPtr<U>& p) |
| { |
| return adoptRef(static_cast<T*>(p.leakRef())); |
| } |
| |
| template <typename T> inline T* getPtr(const PassRefPtr<T>& p) |
| { |
| return p.get(); |
| } |
| |
| } // namespace WTF |
| |
| using WTF::PassRefPtr; |
| using WTF::adoptRef; |
| using WTF::static_pointer_cast; |
| |
| #endif // WTF_PassRefPtr_h |