// Copyright 2020 The Dawn & Tint Authors
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#ifndef SRC_DAWN_NATIVE_POOLEDRESOURCEMEMORYALLOCATOR_H_
#define SRC_DAWN_NATIVE_POOLEDRESOURCEMEMORYALLOCATOR_H_

#include <deque>
#include <memory>

#include "dawn/common/SerialQueue.h"
#include "dawn/native/ResourceHeapAllocator.h"
#include "partition_alloc/pointers/raw_ptr.h"

namespace dawn::native {

class DeviceBase;

// |PooledResourceMemoryAllocator| allocates a fixed-size resource memory from a resource memory
// pool. Internally, it manages a list of heaps using LIFO (newest heaps are recycled first).
// The heap is in one of two states: AVAILABLE or not. Upon de-allocate, the heap is returned
// the pool and made AVAILABLE.
class PooledResourceMemoryAllocator : public ResourceHeapAllocator {
  public:
    explicit PooledResourceMemoryAllocator(ResourceHeapAllocator* heapAllocator);
    ~PooledResourceMemoryAllocator() override;

    ResultOrError<std::unique_ptr<ResourceHeapBase>> AllocateResourceHeap(uint64_t size) override;
    void DeallocateResourceHeap(std::unique_ptr<ResourceHeapBase> allocation) override;

    void DestroyPool();

    // For testing purposes.
    uint64_t GetPoolSizeForTesting() const;

  private:
    raw_ptr<ResourceHeapAllocator> mHeapAllocator = nullptr;

    std::deque<std::unique_ptr<ResourceHeapBase>> mPool;
};

}  // namespace dawn::native

#endif  // SRC_DAWN_NATIVE_POOLEDRESOURCEMEMORYALLOCATOR_H_