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// 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_