MJPEG acceleration for video capture using VAAPI, the GPU and IPC part

content/common/gpu/client/gpu_jpeg_decode_accelerator_host.h

+// Copyright 2015 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 CONTENT_COMMON_GPU_CLIENT_GPU_JPEG_DECODE_ACCELERATOR_HOST_H_
+#define CONTENT_COMMON_GPU_CLIENT_GPU_JPEG_DECODE_ACCELERATOR_HOST_H_
+
+#include "base/memory/weak_ptr.h"
+#include "base/threading/non_thread_safe.h"
+#include "ipc/ipc_listener.h"
+#include "media/video/jpeg_decode_accelerator.h"
+
+namespace base {
+class SingleThreadTaskRunner;
+}
+
+namespace content {
+class GpuChannelHost;
+
+// This class is used to talk to JpegDecodeAccelerator in the GPU process
+// through IPC messages.
+class GpuJpegDecodeAcceleratorHost
+    : public IPC::Listener,
+      public media::JpegDecodeAccelerator,
+      public base::NonThreadSafe,
+      public base::SupportsWeakPtr<GpuJpegDecodeAcceleratorHost> {
+ public:
+  // GpuJpegDecoder owns |this| and |channel|. And GpuJpegDecoder delete |this|
+  // before |channel|. So |this| is guaranteed not to outlive |channel|.
+  GpuJpegDecodeAcceleratorHost(
+      GpuChannelHost* channel,
+      int32 route_id,
+      const scoped_refptr<base::SingleThreadTaskRunner>& io_task_runner);
+  ~GpuJpegDecodeAcceleratorHost() override;
+
+  // IPC::Listener implementation.
+  // Run on IO thread.
+  void OnChannelError() override;
+  bool OnMessageReceived(const IPC::Message& message) override;
+
+  // media::JpegDecodeAccelerator implementation.
+  bool Initialize(media::JpegDecodeAccelerator::Client* client) override;
+  void Decode(const media::BitstreamBuffer& bitstream_buffer,
+              const scoped_refptr<media::VideoFrame>& video_frame) override;
+
+ private:
+  void Send(IPC::Message* message);
+
+  void OnDecodeAck(int32_t bitstream_buffer_id, Error error);
+
+  // Unowned reference to the GpuChannelHost to send IPC messages to the GPU
+  // process.
+  GpuChannelHost* channel_;
+
+  // After Initialize, |client_| is only accessed on IO thread.
+  Client* client_;
+
+  // Route ID for the associated decoder in the GPU process.
+  int32 decoder_route_id_;
+
+  // GPU IO task runner.
+  scoped_refptr<base::SingleThreadTaskRunner> io_task_runner_;
+
+  DISALLOW_COPY_AND_ASSIGN(GpuJpegDecodeAcceleratorHost);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_COMMON_GPU_CLIENT_GPU_JPEG_DECODE_ACCELERATOR_HOST_H_