// Copyright 2017 The Dawn & Tint Authors
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#ifndef SRC_DAWN_NATIVE_D3D12_COMMANDALLOCATORMANAGER_H_
#define SRC_DAWN_NATIVE_D3D12_COMMANDALLOCATORMANAGER_H_

#include <bitset>

#include "dawn/native/d3d12/d3d12_platform.h"

#include "dawn/common/SerialQueue.h"
#include "dawn/native/Error.h"
#include "dawn/native/IntegerTypes.h"

namespace dawn::native::d3d12 {

class Queue;

class CommandAllocatorManager {
  public:
    explicit CommandAllocatorManager(Queue* queue);

    // A CommandAllocator that is reserved must be used on the next ExecuteCommandLists
    // otherwise its commands may be reset before execution has completed on the GPU
    ResultOrError<ID3D12CommandAllocator*> ReserveCommandAllocator();
    MaybeError Tick(ExecutionSerial lastCompletedSerial);

  private:
    // The allocator manager is owned by the queue so the queue outlives it.
    Queue* mQueue;

    // This must be at least 2 because the Device and Queue use separate command allocators
    static constexpr unsigned int kMaxCommandAllocators = 32;
    unsigned int mAllocatorCount;

    struct IndexedCommandAllocator {
        ComPtr<ID3D12CommandAllocator> commandAllocator;
        unsigned int index;
    };

    ComPtr<ID3D12CommandAllocator> mCommandAllocators[kMaxCommandAllocators];
    std::bitset<kMaxCommandAllocators> mFreeAllocators;
    SerialQueue<ExecutionSerial, IndexedCommandAllocator> mInFlightCommandAllocators;
};

}  // namespace dawn::native::d3d12

#endif  // SRC_DAWN_NATIVE_D3D12_COMMANDALLOCATORMANAGER_H_
