/* * 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 namespace WTF { template class RefPtr; template class PassRefPtr; template ALWAYS_INLINE void refIfNotNull(T* ptr) { if (LIKELY(ptr != nullptr)) ptr->ref(); } template ALWAYS_INLINE void derefIfNotNull(T* ptr) { if (LIKELY(ptr != nullptr)) ptr->deref(); } template class PassRefPtr { public: typedef T ValueType; typedef ValueType* PtrType; PassRefPtr() : m_ptr(nullptr) { } PassRefPtr(T* ptr) : m_ptr(ptr) { refIfNotNull(ptr); } // 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 PassRefPtr(const PassRefPtr& o) : m_ptr(o.leakRef()) { } ALWAYS_INLINE ~PassRefPtr() { derefIfNotNull(std::exchange(m_ptr, nullptr)); } template PassRefPtr(const RefPtr&); template PassRefPtr(Ref&& reference) : m_ptr(&reference.leakRef()) { } template PassRefPtr(RefPtr&& reference) : m_ptr(reference.leakRef()) { } 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 : nullptr; } template friend PassRefPtr static_pointer_cast(const PassRefPtr&); private: PassRefPtr& operator=(const PassRefPtr&) = delete; enum AdoptTag { Adopt }; PassRefPtr(T* ptr, AdoptTag) : m_ptr(ptr) { } mutable T* m_ptr; }; template template inline PassRefPtr::PassRefPtr(const RefPtr& o) : m_ptr(o.get()) { T* ptr = m_ptr; refIfNotNull(ptr); } template inline T* PassRefPtr::leakRef() const { return std::exchange(m_ptr, nullptr); } template inline bool operator==(const PassRefPtr& a, const PassRefPtr& b) { return a.get() == b.get(); } template inline bool operator==(const PassRefPtr& a, const RefPtr& b) { return a.get() == b.get(); } template inline bool operator==(const RefPtr& a, const PassRefPtr& b) { return a.get() == b.get(); } template inline bool operator==(const PassRefPtr& a, U* b) { return a.get() == b; } template inline bool operator==(T* a, const PassRefPtr& b) { return a == b.get(); } template inline bool operator!=(const PassRefPtr& a, const PassRefPtr& b) { return a.get() != b.get(); } template inline bool operator!=(const PassRefPtr& a, const RefPtr& b) { return a.get() != b.get(); } template inline bool operator!=(const RefPtr& a, const PassRefPtr& b) { return a.get() != b.get(); } template inline bool operator!=(const PassRefPtr& a, U* b) { return a.get() != b; } template inline bool operator!=(T* a, const PassRefPtr& b) { return a != b.get(); } template inline PassRefPtr static_pointer_cast(const PassRefPtr& p) { return PassRefPtr(static_cast(p.leakRef()), PassRefPtr::Adopt); } template struct IsSmartPtr> { static const bool value = true; }; } // namespace WTF using WTF::PassRefPtr; using WTF::static_pointer_cast; #endif // WTF_PassRefPtr_h