src/dawn/wire/WireDeserializeAllocator.h

// Copyright 2019 The Dawn & Tint Authors
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#ifndef SRC_DAWN_WIRE_WIREDESERIALIZEALLOCATOR_H_
#define SRC_DAWN_WIRE_WIREDESERIALIZEALLOCATOR_H_

#include <optional>
#include <vector>

#include "dawn/wire/WireCmd_autogen.h"
#include "partition_alloc/pointers/raw_ptr.h"
#include "src/utils/heap_array.h"
#include "src/utils/span.h"

namespace dawn::wire {
// A really really simple implementation of the DeserializeAllocator. It's main feature
// is that it has some inline storage so as to avoid allocations for the majority of
// commands.
class WireDeserializeAllocator : public DeserializeAllocator {
  public:
    WireDeserializeAllocator();
    virtual ~WireDeserializeAllocator();

    std::optional<Span<std::byte>> TryGetSpace(size_t size) override;

    void Reset();

  private:
    static constexpr size_t kDefaultBufferSize = 2048;

    std::array<std::byte, kDefaultBufferSize> mStaticBuffer;
    std::vector<HeapArray<std::byte>> mAllocations;
    // TODO(https://crbug.com/526537224): Maybe use RawSpan instead of Span, but we will need to
    // verify that works with the static buffer also.
    Span<std::byte> mCurrentBuffer = mStaticBuffer;
};
}  // namespace dawn::wire

#endif  // SRC_DAWN_WIRE_WIREDESERIALIZEALLOCATOR_H_