chromium/gpu/command_buffer/common/shm_count.h

// Copyright 2017 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef GPU_COMMAND_BUFFER_COMMON_SHM_COUNT_H_
#define GPU_COMMAND_BUFFER_COMMON_SHM_COUNT_H_

#include <atomic>

#include "base/memory/raw_ptr.h"
#include "base/memory/shared_memory_mapping.h"
#include "base/memory/unsafe_shared_memory_region.h"
#include "gpu/gpu_export.h"

namespace gpu {

// Base class for GpuProcessShmCount and GpuProcessHostShmCount,
// can not be used directly.
class GPU_EXPORT ShmCountBase { … };

// Provides write-only access to the count for the gpu process.
// It is safe to use ScopedIncrement from multiple threads on the same instance
// of GpuProcessShmCount.
class GPU_EXPORT GpuProcessShmCount : public ShmCountBase { … };

// Provides read-only access to the count for the browser process.
// GpuProcessHostShmCount will initialize a new mojo shared buffer. The
// handle to this buffer should be passed to the GPU process via CloneHandle.
// The GPU process will then increment the count, which can be read via this
// class.
class GPU_EXPORT GpuProcessHostShmCount : public ShmCountBase { … };

}  // namespace gpu

#endif  // GPU_COMMAND_BUFFER_COMMON_SHM_COUNT_H_