// Copyright 2017 The Dawn Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#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 Device;

class CommandAllocatorManager {
  public:
    explicit CommandAllocatorManager(Device* device);

    // 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:
    Device* device;

    // 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_