| // Copyright 2017 The Dawn & Tint Authors |
| // |
| // Redistribution and use in source and binary forms, with or without |
| // modification, are permitted provided that the following conditions are met: |
| // |
| // 1. Redistributions of source code must retain the above copyright notice, this |
| // list of conditions and the following disclaimer. |
| // |
| // 2. Redistributions in binary form must reproduce the above copyright notice, |
| // this list of conditions and the following disclaimer in the documentation |
| // and/or other materials provided with the distribution. |
| // |
| // 3. Neither the name of the copyright holder nor the names of its |
| // contributors may be used to endorse or promote products derived from |
| // this software without specific prior written permission. |
| // |
| // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" |
| // AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| // IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE |
| // DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE |
| // FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
| // DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR |
| // SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER |
| // CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, |
| // OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
| // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| |
| #ifndef SRC_DAWN_COMMON_REFCOUNTED_H_ |
| #define SRC_DAWN_COMMON_REFCOUNTED_H_ |
| |
| #include <atomic> |
| #include <cstdint> |
| #include <type_traits> |
| |
| namespace dawn { |
| |
| namespace detail { |
| class WeakRefData; |
| } // namespace detail |
| |
| class RefCount { |
| public: |
| RefCount(uint64_t initCount, uint64_t payload); |
| |
| // Create a refcount with a payload. The refcount starts initially at one. |
| explicit RefCount(uint64_t payload = 0); |
| |
| uint64_t GetValueForTesting() const; |
| uint64_t GetPayload() const; |
| |
| // Add a reference, return true if the previous count is 0. |
| bool Increment(); |
| |
| // Tries to add a reference. Returns false if the ref count is already at 0. This is used when |
| // operating on a raw pointer to a RefCounted instead of a valid Ref that may be soon deleted. |
| bool TryIncrement(); |
| |
| // Remove a reference. Returns true if this was the last reference. |
| bool Decrement(); |
| |
| private: |
| std::atomic<uint64_t> mRefCount; |
| }; |
| |
| class RefCounted { |
| public: |
| static constexpr bool HasExternalRefCount = false; |
| |
| explicit RefCounted(uint64_t payload = 0); |
| |
| uint64_t GetRefCountForTesting() const; |
| uint64_t GetRefCountPayload() const; |
| |
| void AddRef(); |
| // Release() is called by internal code, so it's assumed that there is already a thread |
| // synchronization in place for destruction. |
| void Release(); |
| |
| // TODO(dawn:2234): Deprecated. Remove when no longer used. |
| void APIReference() { APIAddRef(); } |
| void APIAddRef() { AddRef(); } |
| void APIRelease() { Release(); } |
| |
| protected: |
| // Friend class is needed to access the RefCount to TryIncrement. |
| friend class detail::WeakRefData; |
| |
| virtual ~RefCounted(); |
| |
| void ReleaseAndLockBeforeDestroy(); |
| |
| // A Derived class may override these if they require a custom deleter. |
| virtual void DeleteThis(); |
| // This calls DeleteThis() by default. |
| virtual void LockAndDeleteThis(); |
| |
| RefCount mRefCount; |
| }; |
| |
| } // namespace dawn |
| |
| #endif // SRC_DAWN_COMMON_REFCOUNTED_H_ |