gpu/ipc/client/image_decode_accelerator_proxy.h

// Copyright 2018 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 GPU_IPC_CLIENT_IMAGE_DECODE_ACCELERATOR_PROXY_H_
#define GPU_IPC_CLIENT_IMAGE_DECODE_ACCELERATOR_PROXY_H_

#include <vector>

#include "base/macros.h"
#include "base/synchronization/lock.h"
#include "base/thread_annotations.h"
#include "gpu/command_buffer/common/sync_token.h"

namespace gfx {
class ColorSpace;
class Size;
}  // namespace gfx

namespace gpu {
class GpuChannelHost;

// A client-side interface to schedule hardware-accelerated image decodes on the
// GPU process. This is only supported in OOP-R mode. To use this functionality,
// the renderer should first find out the supported image types (e.g., JPEG,
// WebP, etc.) and profiles (e.g., a maximum size of 8192x8192). This
// information can be obtained from GpuInfo. No decode requests should be sent
// for unsupported image types/profiles.
//
// The actual decode is done asynchronously on the service side, but the client
// can synchronize using a sync token that will be released upon the completion
// of the decode.
//
// To send a decode request, the renderer should:
//
// (1) Create a locked ClientImageTransferCacheEntry without a backing
//     SkPixmap. This entry should not be serialized over the command buffer.
//
// (2) Call ScheduleImageDecode().
//
// (3) Issue a server wait on the sync token returned in step (2).
//
// When the service is done with the decode, a ServiceImageTransferCacheEntry
// will be created/locked with the decoded data and the sync token is
// released.
//
// Objects of this class are thread-safe.
//
// TODO(andrescj): actually put the decoder's capabilities in GpuInfo.
class ImageDecodeAcceleratorProxy {
 public:
  ImageDecodeAcceleratorProxy(GpuChannelHost* host, int32_t route_id);
  ~ImageDecodeAcceleratorProxy();

  // Schedules a hardware-accelerated image decode on the GPU process. The image
  // in |encoded_data| is decoded and scaled to |output_size|. Upon completion,
  // a service-side transfer cache entry will be created with the decoded data
  // using |transfer_cache_entry_id|, |discardable_handle_shm_id|, and
  // |discardable_handle_shm_offset|. The |raster_decoder_route_id| is used to
  // look up the appropriate command buffer and create the transfer cache entry
  // correctly. Returns a sync token that will be released after the decode is
  // done and the service-side transfer cache entry is created.
  SyncToken ScheduleImageDecode(const std::vector<uint8_t>& encoded_data,
                                const gfx::Size& output_size,
                                int32_t raster_decoder_route_id,
                                uint32_t transfer_cache_entry_id,
                                int32_t discardable_handle_shm_id,
                                uint32_t discardable_handle_shm_offset,
                                const gfx::ColorSpace& target_color_space,
                                bool needs_mips);

 private:
  GpuChannelHost* const host_;
  const int32_t route_id_;

  base::Lock lock_;
  uint64_t next_release_count_ GUARDED_BY(lock_) = 0;

  DISALLOW_COPY_AND_ASSIGN(ImageDecodeAcceleratorProxy);
};

}  // namespace gpu

#endif  // GPU_IPC_CLIENT_IMAGE_DECODE_ACCELERATOR_PROXY_H_