// Copyright 2016 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef CC_RASTER_STAGING_BUFFER_POOL_H_
#define CC_RASTER_STAGING_BUFFER_POOL_H_

#include <stdint.h>

#include <memory>
#include <set>

#include "base/containers/circular_deque.h"
#include "base/memory/memory_pressure_listener.h"
#include "base/memory/weak_ptr.h"
#include "base/sequenced_task_runner.h"
#include "base/synchronization/lock.h"
#include "base/time/time.h"
#include "base/trace_event/memory_dump_provider.h"
#include "base/trace_event/trace_event.h"
#include "cc/cc_export.h"
#include "components/viz/common/resources/resource_format.h"
#include "gpu/command_buffer/common/gl2_types.h"
#include "gpu/command_buffer/common/mailbox.h"
#include "gpu/command_buffer/common/sync_token.h"
#include "ui/gfx/geometry/size.h"
#include "ui/gfx/gpu_memory_buffer.h"

namespace gfx {
class GpuMemoryBuffer;
}
namespace gpu {
namespace raster {
class RasterInterface;
}
class SharedImageInterface;
}  // namespace gpu

namespace viz {
class RasterContextProvider;
}  // namespace viz

namespace cc {

struct StagingBuffer {
  StagingBuffer(const gfx::Size& size, viz::ResourceFormat format);
  ~StagingBuffer();

  void DestroyGLResources(gpu::raster::RasterInterface* gl,
                          gpu::SharedImageInterface* sii);
  void OnMemoryDump(base::trace_event::ProcessMemoryDump* pmd,
                    viz::ResourceFormat format,
                    bool is_free) const;

  const gfx::Size size;
  const viz::ResourceFormat format;
  base::TimeTicks last_usage;

  // The following fields are initialized by OneCopyRasterBufferProvider.
  // Storage for the staging buffer.  This can be a GPU native or shared memory
  // GpuMemoryBuffer.
  std::unique_ptr<gfx::GpuMemoryBuffer> gpu_memory_buffer;

  // Mailbox for the shared image bound to the GpuMemoryBuffer.
  gpu::Mailbox mailbox;

  // Sync token for the last RasterInterface operations using the shared image.
  gpu::SyncToken sync_token;

  // Id of command buffer query that tracks use of this staging buffer by the
  // GPU.  In general, GPU synchronization is necessary for native
  // GpuMemoryBuffers.
  GLuint query_id = 0;

  // Id of the content that's rastered into this staging buffer.  Used to
  // retrieve staging buffer with known content for reuse for partial raster.
  uint64_t content_id = 0;
};

class CC_EXPORT StagingBufferPool
    : public base::trace_event::MemoryDumpProvider {
 public:
  StagingBufferPool(scoped_refptr<base::SequencedTaskRunner> task_runner,
                    viz::RasterContextProvider* worker_context_provider,
                    bool use_partial_raster,
                    int max_staging_buffer_usage_in_bytes);
  StagingBufferPool(const StagingBufferPool&) = delete;
  ~StagingBufferPool() final;

  StagingBufferPool& operator=(const StagingBufferPool&) = delete;

  void Shutdown();

  // Overridden from base::trace_event::MemoryDumpProvider:
  bool OnMemoryDump(const base::trace_event::MemoryDumpArgs& args,
                    base::trace_event::ProcessMemoryDump* pmd) override;

  std::unique_ptr<StagingBuffer> AcquireStagingBuffer(
      const gfx::Size& size,
      viz::ResourceFormat format,
      uint64_t previous_content_id);
  void ReleaseStagingBuffer(std::unique_ptr<StagingBuffer> staging_buffer);

 private:
  void AddStagingBuffer(const StagingBuffer* staging_buffer,
                        viz::ResourceFormat format);
  void RemoveStagingBuffer(const StagingBuffer* staging_buffer);
  void MarkStagingBufferAsFree(const StagingBuffer* staging_buffer);
  void MarkStagingBufferAsBusy(const StagingBuffer* staging_buffer);

  base::TimeTicks GetUsageTimeForLRUBuffer();
  void ScheduleReduceMemoryUsage();
  void ReduceMemoryUsage();
  void ReleaseBuffersNotUsedSince(base::TimeTicks time);

  std::unique_ptr<base::trace_event::ConvertableToTraceFormat> StateAsValue()
      const;
  void StagingStateAsValueInto(
      base::trace_event::TracedValue* staging_state) const;

  void OnMemoryPressure(
      base::MemoryPressureListener::MemoryPressureLevel level);

  scoped_refptr<base::SequencedTaskRunner> task_runner_;
  viz::RasterContextProvider* const worker_context_provider_;
  const bool use_partial_raster_;

  mutable base::Lock lock_;
  // |lock_| must be acquired when accessing the following members.
  using StagingBufferSet = std::set<const StagingBuffer*>;
  StagingBufferSet buffers_;
  using StagingBufferDeque =
      base::circular_deque<std::unique_ptr<StagingBuffer>>;
  StagingBufferDeque free_buffers_;
  StagingBufferDeque busy_buffers_;
  const int max_staging_buffer_usage_in_bytes_;
  int staging_buffer_usage_in_bytes_;
  int free_staging_buffer_usage_in_bytes_;
  const base::TimeDelta staging_buffer_expiration_delay_;
  bool reduce_memory_usage_pending_;
  base::RepeatingClosure reduce_memory_usage_callback_;

  std::unique_ptr<base::MemoryPressureListener> memory_pressure_listener_;

  base::WeakPtrFactory<StagingBufferPool> weak_ptr_factory_;
};

}  // namespace cc

#endif  // CC_RASTER_STAGING_BUFFER_POOL_H_