| // Copyright 2016 PDFium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| // Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com |
| |
| #ifndef CORE_FXCRT_WEAK_PTR_H_ |
| #define CORE_FXCRT_WEAK_PTR_H_ |
| |
| #include <stdint.h> |
| |
| #include <cstddef> |
| #include <memory> |
| #include <utility> |
| |
| #include "core/fxcrt/fx_system.h" |
| #include "core/fxcrt/retain_ptr.h" |
| |
| namespace fxcrt { |
| |
| template <class T, class D = std::default_delete<T>> |
| class WeakPtr { |
| public: |
| WeakPtr() = default; |
| WeakPtr(const WeakPtr& that) : m_pHandle(that.m_pHandle) {} |
| WeakPtr(WeakPtr&& that) noexcept { Swap(that); } |
| explicit WeakPtr(std::unique_ptr<T, D> pObj) |
| : m_pHandle(new Handle(std::move(pObj))) {} |
| |
| // Deliberately implicit to allow passing nullptr. |
| // NOLINTNEXTLINE(runtime/explicit) |
| WeakPtr(std::nullptr_t arg) {} |
| |
| explicit operator bool() const { return m_pHandle && !!m_pHandle->Get(); } |
| bool HasOneRef() const { return m_pHandle && m_pHandle->HasOneRef(); } |
| T* operator->() { return m_pHandle->Get(); } |
| const T* operator->() const { return m_pHandle->Get(); } |
| WeakPtr& operator=(const WeakPtr& that) { |
| m_pHandle = that.m_pHandle; |
| return *this; |
| } |
| bool operator==(const WeakPtr& that) const { |
| return m_pHandle == that.m_pHandle; |
| } |
| bool operator!=(const WeakPtr& that) const { return !(*this == that); } |
| |
| T* Get() const { return m_pHandle ? m_pHandle->Get() : nullptr; } |
| void DeleteObject() { |
| if (m_pHandle) { |
| m_pHandle->Clear(); |
| m_pHandle.Reset(); |
| } |
| } |
| void Reset() { m_pHandle.Reset(); } |
| void Reset(std::unique_ptr<T, D> pObj) { |
| m_pHandle.Reset(new Handle(std::move(pObj))); |
| } |
| void Swap(WeakPtr& that) { m_pHandle.Swap(that.m_pHandle); } |
| |
| private: |
| class Handle { |
| public: |
| explicit Handle(std::unique_ptr<T, D> ptr) : m_pObj(std::move(ptr)) {} |
| |
| void Reset(std::unique_ptr<T, D> ptr) { m_pObj = std::move(ptr); } |
| void Clear() { // Now you're all weak ptrs ... |
| m_pObj.reset(); // unique_ptr nulls first before invoking delete. |
| } |
| T* Get() const { return m_pObj.get(); } |
| T* Retain() { |
| ++m_nCount; |
| return m_pObj.get(); |
| } |
| void Release() { |
| if (--m_nCount == 0) |
| delete this; |
| } |
| bool HasOneRef() const { return m_nCount == 1; } |
| |
| private: |
| ~Handle() = default; |
| |
| intptr_t m_nCount = 0; |
| std::unique_ptr<T, D> m_pObj; |
| }; |
| |
| RetainPtr<Handle> m_pHandle; |
| }; |
| |
| } // namespace fxcrt |
| |
| using fxcrt::WeakPtr; |
| |
| #endif // CORE_FXCRT_WEAK_PTR_H_ |