src/dawn/native/ResourceMemoryAllocation.h

// Copyright 2018 The Dawn & Tint Authors
//
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#ifndef SRC_DAWN_NATIVE_RESOURCEMEMORYALLOCATION_H_
#define SRC_DAWN_NATIVE_RESOURCEMEMORYALLOCATION_H_

#include <cstdint>

namespace dawn::native {

class ResourceHeapBase;

// Allocation method determines how memory was sub-divided.
// Used by the device to get the allocator that was responsible for the allocation.
enum class AllocationMethod {
    // Memory not sub-divided.
    kDirect,

    // Memory sub-divided using one or more blocks of various sizes.
    kSubAllocated,

    // Memory was allocated outside of Dawn.
    kExternal,

    // Memory not allocated or freed.
    kInvalid
};

// Metadata that describes how the allocation was allocated.
struct AllocationInfo {
    // AllocationInfo contains a separate offset to not confuse block vs memory offsets.
    // The block offset is within the entire allocator memory range and only required by the
    // buddy sub-allocator to get the corresponding memory. Unlike the block offset, the
    // allocation offset is always local to the memory.
    uint64_t mBlockOffset = 0;

    AllocationMethod mMethod = AllocationMethod::kInvalid;
};

// Handle into a resource heap pool.
class ResourceMemoryAllocation {
  public:
    ResourceMemoryAllocation();
    ResourceMemoryAllocation(const AllocationInfo& info,
                             uint64_t offset,
                             ResourceHeapBase* resourceHeap,
                             uint8_t* mappedPointer = nullptr);
    virtual ~ResourceMemoryAllocation() = default;

    ResourceMemoryAllocation(const ResourceMemoryAllocation&) = default;
    ResourceMemoryAllocation& operator=(const ResourceMemoryAllocation&) = default;

    ResourceHeapBase* GetResourceHeap() const;
    uint64_t GetOffset() const;
    uint8_t* GetMappedPointer() const;
    AllocationInfo GetInfo() const;

    virtual void Invalidate();

  private:
    AllocationInfo mInfo;
    uint64_t mOffset;
    ResourceHeapBase* mResourceHeap;
    uint8_t* mMappedPointer;
};
}  // namespace dawn::native

#endif  // SRC_DAWN_NATIVE_RESOURCEMEMORYALLOCATION_H_