src/dawn/native/Buffer.h

// Copyright 2017 The Dawn & Tint Authors
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
// 1. Redistributions of source code must retain the above copyright notice, this
//    list of conditions and the following disclaimer.
//
// 2. Redistributions in binary form must reproduce the above copyright notice,
//    this list of conditions and the following disclaimer in the documentation
//    and/or other materials provided with the distribution.
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// 3. Neither the name of the copyright holder nor the names of its
//    contributors may be used to endorse or promote products derived from
//    this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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#ifndef SRC_DAWN_NATIVE_BUFFER_H_
#define SRC_DAWN_NATIVE_BUFFER_H_

#include <functional>
#include <memory>

#include "dawn/common/FutureUtils.h"
#include "dawn/common/NonCopyable.h"
#include "partition_alloc/pointers/raw_ptr.h"

#include "dawn/native/Error.h"
#include "dawn/native/Forward.h"
#include "dawn/native/IntegerTypes.h"
#include "dawn/native/ObjectBase.h"
#include "dawn/native/SharedBufferMemory.h"
#include "dawn/native/UsageValidationMode.h"

#include "dawn/native/dawn_platform.h"

namespace dawn::native {

struct CopyTextureToBufferCmd;

enum class MapType : uint32_t;

ResultOrError<UnpackedPtr<BufferDescriptor>> ValidateBufferDescriptor(
    DeviceBase* device,
    const BufferDescriptor* descriptor);

static constexpr wgpu::BufferUsage kReadOnlyBufferUsages =
    wgpu::BufferUsage::MapRead | wgpu::BufferUsage::CopySrc | wgpu::BufferUsage::Index |
    wgpu::BufferUsage::Vertex | wgpu::BufferUsage::Uniform | kReadOnlyStorageBuffer |
    wgpu::BufferUsage::Indirect;

static constexpr wgpu::BufferUsage kMappableBufferUsages =
    wgpu::BufferUsage::MapRead | wgpu::BufferUsage::MapWrite;

static constexpr wgpu::BufferUsage kShaderBufferUsages =
    wgpu::BufferUsage::Uniform | wgpu::BufferUsage::Storage | kInternalStorageBuffer |
    kReadOnlyStorageBuffer;

static constexpr wgpu::BufferUsage kReadOnlyShaderBufferUsages =
    kShaderBufferUsages & kReadOnlyBufferUsages;

class BufferBase : public ApiObjectBase {
  public:
    enum class BufferState {
        Unmapped,
        PendingMap,
        Mapped,
        MappedAtCreation,
        HostMappedPersistent,
        SharedMemoryNoAccess,
        Destroyed,
    };
    static Ref<BufferBase> MakeError(DeviceBase* device, const BufferDescriptor* descriptor);

    ObjectType GetType() const override;

    uint64_t GetSize() const;
    uint64_t GetAllocatedSize() const;
    ExecutionSerial GetLastUsageSerial() const;

    // |GetUsageExternalOnly| returns the usage with which the buffer was created using the
    // base WebGPU API. Additional usages may be added for internal state tracking. |GetUsage|
    // returns the union of base usage and the usages added internally.
    wgpu::BufferUsage GetUsage() const;
    wgpu::BufferUsage GetUsageExternalOnly() const;

    MaybeError MapAtCreation();
    void CallbackOnMapRequestCompleted(MapRequestID mapID, WGPUBufferMapAsyncStatus status);

    MaybeError ValidateCanUseOnQueueNow() const;

    bool IsFullBufferRange(uint64_t offset, uint64_t size) const;
    bool NeedsInitialization() const;
    bool IsDataInitialized() const;
    void SetIsDataInitialized();
    void MarkUsedInPendingCommands();

    // SetHasAccess determines Dawn's ability to access SharedBufferMemory.
    void SetHasAccess(bool hasAccess);

    virtual void* GetMappedPointer() = 0;
    void* GetMappedRange(size_t offset, size_t size, bool writable = true);
    MaybeError Unmap();

    // Dawn API
    void APIMapAsync(wgpu::MapMode mode,
                     size_t offset,
                     size_t size,
                     WGPUBufferMapCallback callback,
                     void* userdata);
    Future APIMapAsyncF(wgpu::MapMode mode,
                        size_t offset,
                        size_t size,
                        const BufferMapCallbackInfo& callbackInfo);
    void* APIGetMappedRange(size_t offset, size_t size);
    const void* APIGetConstMappedRange(size_t offset, size_t size);
    void APIUnmap();
    void APIDestroy();
    wgpu::BufferUsage APIGetUsage() const;
    wgpu::BufferMapState APIGetMapState() const;
    uint64_t APIGetSize() const;

  protected:
    BufferBase(DeviceBase* device, const UnpackedPtr<BufferDescriptor>& descriptor);
    BufferBase(DeviceBase* device, const BufferDescriptor* descriptor, ObjectBase::ErrorTag tag);

    void DestroyImpl() override;

    ~BufferBase() override;

    MaybeError MapAtCreationInternal();

    uint64_t mAllocatedSize = 0;

    ExecutionSerial mLastUsageSerial = ExecutionSerial(0);

    // The shared buffer memory state the buffer was created from. May be null.
    Ref<SharedBufferMemoryContents> mSharedBufferMemoryContents;

  private:
    std::function<void()> PrepareMappingCallback(MapRequestID mapID,
                                                 WGPUBufferMapAsyncStatus status);

    virtual MaybeError MapAtCreationImpl() = 0;
    virtual MaybeError MapAsyncImpl(wgpu::MapMode mode, size_t offset, size_t size) = 0;
    virtual void UnmapImpl() = 0;

    virtual bool IsCPUWritableAtCreation() const = 0;
    MaybeError CopyFromStagingBuffer();

    MaybeError ValidateMapAsync(wgpu::MapMode mode,
                                size_t offset,
                                size_t size,
                                WGPUBufferMapAsyncStatus* status) const;
    MaybeError ValidateUnmap() const;
    bool CanGetMappedRange(bool writable, size_t offset, size_t size) const;
    void UnmapInternal(WGPUBufferMapAsyncStatus callbackStatus);

    const uint64_t mSize = 0;
    const wgpu::BufferUsage mUsage = wgpu::BufferUsage::None;
    BufferState mState;
    bool mIsDataInitialized = false;

    // mStagingBuffer is used to implement mappedAtCreation for
    // buffers with non-mappable usage. It is transiently allocated
    // and released when the mappedAtCreation-buffer is unmapped.
    // Because `mStagingBuffer` itself is directly mappable, it will
    // not create another staging buffer.
    // i.e. buffer->mStagingBuffer->mStagingBuffer... is not possible.
    Ref<BufferBase> mStagingBuffer;

    WGPUBufferMapCallback mMapCallback = nullptr;
    // TODO(https://crbug.com/dawn/2349): Investigate DanglingUntriaged in dawn/native.
    raw_ptr<void, DanglingUntriaged> mMapUserdata = nullptr;
    MapRequestID mLastMapID = MapRequestID(0);
    wgpu::MapMode mMapMode = wgpu::MapMode::None;
    size_t mMapOffset = 0;
    size_t mMapSize = 0;

    struct MapAsyncEvent;
    FutureID mPendingMapFutureID = kNullFutureID;
    Ref<MapAsyncEvent> mPendingMapEvent;
};

}  // namespace dawn::native

#endif  // SRC_DAWN_NATIVE_BUFFER_H_