Buffer.h - mozsearch

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/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */

/* This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this

 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#ifndef GPU_BUFFER_H_

#define GPU_BUFFER_H_

#include "js/RootingAPI.h"

#include "mozilla/dom/Nullable.h"

#include "mozilla/webgpu/WebGPUTypes.h"

#include "nsTArray.h"

#include "ObjectModel.h"

#include "mozilla/ipc/RawShmem.h"

#include <memory>

namespace mozilla {

class ErrorResult;

namespace dom {

struct GPUBufferDescriptor;

template <typename T>

class Optional;

enum class GPUBufferMapState : uint8_t;

}  // namespace dom

namespace webgpu {

class Device;

struct MappedInfo {

  // True if mapping is requested for writing.

  bool mWritable = false;

  // Populated by `GetMappedRange`.

  nsTArray<JS::Heap<JSObject*>> mArrayBuffers;

  BufferAddress mOffset;

  BufferAddress mSize;

  MappedInfo() = default;

  MappedInfo(const MappedInfo&) = delete;

};

class Buffer final : public ObjectBase, public ChildOf<Device> {

 public:

  NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_NATIVE_CLASS(Buffer)

  NS_INLINE_DECL_CYCLE_COLLECTING_NATIVE_REFCOUNTING(Buffer)

  GPU_DECL_JS_WRAP(Buffer)

  static already_AddRefed<Buffer> Create(Device* aDevice, RawId aDeviceId,

                                         const dom::GPUBufferDescriptor& aDesc,

                                         ErrorResult& aRv);

  already_AddRefed<dom::Promise> MapAsync(uint32_t aMode, uint64_t aOffset,

                                          const dom::Optional<uint64_t>& aSize,

                                          ErrorResult& aRv);

  void GetMappedRange(JSContext* aCx, uint64_t aOffset,

                      const dom::Optional<uint64_t>& aSize,

                      JS::Rooted<JSObject*>* aObject, ErrorResult& aRv);

  void Unmap(JSContext* aCx, ErrorResult& aRv);

  void Destroy(JSContext* aCx, ErrorResult& aRv);

  const RawId mId;

  uint64_t Size() const { return mSize; }

  uint32_t Usage() const { return mUsage; }

  dom::GPUBufferMapState MapState() const;

 private:

  Buffer(Device* const aParent, RawId aId, BufferAddress aSize, uint32_t aUsage,

         ipc::WritableSharedMemoryMapping&& aShmem);

  virtual ~Buffer();

  Device& GetDevice() { return *mParent; }

  void Cleanup();

  void UnmapArrayBuffers(JSContext* aCx, ErrorResult& aRv);

  void RejectMapRequest(dom::Promise* aPromise, nsACString& message);

  void AbortMapRequest();

  void SetMapped(BufferAddress aOffset, BufferAddress aSize, bool aWritable);

  // Note: we can't map a buffer with the size that don't fit into `size_t`

  // (which may be smaller than `BufferAddress`), but general not all buffers

  // are mapped.

  const BufferAddress mSize;

  const uint32_t mUsage;

  nsString mLabel;

  // Information about the currently active mapping.

  Maybe<MappedInfo> mMapped;

  RefPtr<dom::Promise> mMapRequest;

  // mShmem does not point to a shared memory segment if the buffer is not

  // mappable.

  std::shared_ptr<ipc::WritableSharedMemoryMapping> mShmem;

};

}  // namespace webgpu

}  // namespace mozilla

#endif  // GPU_BUFFER_H_