Mojify demuxers and allow running {Chunk/FFmpeg}Demuxer in a Utility Process

media/mojo/common/mojo_data_buffer_converter.h

+// Copyright 2017 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 MEDIA_MOJO_COMMON_MOJO_DATA_BUFFER_CONVERTER_
+#define MEDIA_MOJO_COMMON_MOJO_DATA_BUFFER_CONVERTER_
+
+#include "base/macros.h"
+#include "base/memory/ref_counted.h"
+#include "media/mojo/interfaces/media_types.mojom.h"
+#include "mojo/public/cpp/system/data_pipe.h"
+#include "mojo/public/cpp/system/watcher.h"
+
+namespace media {
+
+class DataBuffer;
+
+// A helper class that converts mojom::DataBuffer to media::DataBuffer.
+// The data part of the DataBuffer is read from a DataPipe.
+class MojoDataBufferReader {
+ public:
+  using ReadCB = base::OnceCallback<void(scoped_refptr<DataBuffer>)>;
+
+  // Creates a MojoDataBufferReader of |type| and set the |producer_handle|.
+  static std::unique_ptr<MojoDataBufferReader> Create(
+      uint32_t capacity_num_bytes,
+      mojo::ScopedDataPipeProducerHandle* producer_handle);
+
+  // Hold the consumer handle to read DataBuffer data.
+  explicit MojoDataBufferReader(
+      mojo::ScopedDataPipeConsumerHandle consumer_handle);
+
+  ~MojoDataBufferReader();
+
+  // Converts |buffer| into a DataBuffer (read data from DataPipe if needed).
+  // |read_cb| is called with the result DataBuffer.
+  // Reports a null DataBuffer in case of an error.
+  void ReadDataBuffer(mojom::DataBufferPtr buffer, ReadCB read_cb);
+
+ private:
+  void OnPipeError(MojoResult result);
+  void OnPipeReadable(MojoResult result);
+  void ReadDataBufferData();
+
+  // For reading the data section of a DataBuffer.
+  mojo::ScopedDataPipeConsumerHandle consumer_handle_;
+  mojo::Watcher pipe_watcher_;
+
+  // Only valid during pending read.
+  ReadCB read_cb_;
+  scoped_refptr<DataBuffer> media_buffer_;
+  uint32_t bytes_read_;
+
+  DISALLOW_COPY_AND_ASSIGN(MojoDataBufferReader);
+};
+
+// A helper class that converts media::DataBuffer to mojom::DataBuffer.
+// The data part of the DataBuffer is written into a DataPipe.
+class MojoDataBufferWriter {
+ public:
+  // Creates a MojoDataBufferWriter of |type| and set the |consumer_handle|.
+  static std::unique_ptr<MojoDataBufferWriter> Create(
+      uint32_t capacity_num_bytes,
+      mojo::ScopedDataPipeConsumerHandle* consumer_handle);
+
+  // Hold the producer handle to write DataBuffer data.
+  explicit MojoDataBufferWriter(
+      mojo::ScopedDataPipeProducerHandle producer_handle);
+
+  ~MojoDataBufferWriter();
+
+  // Converts a DataBuffer into mojo DataBuffer.
+  // DataBuffer data is asynchronously written into DataPipe if needed.
+  // Returns null if conversion failed or if the data pipe is already closed.
+  mojom::DataBufferPtr WriteDataBuffer(
+      const scoped_refptr<DataBuffer>& media_buffer);
+
+ private:
+  void OnPipeError(MojoResult result);
+  void OnPipeWritable(MojoResult result);
+  MojoResult WriteDataBufferData();
+
+  // For writing the data section of DataBuffer into DataPipe.
+  mojo::ScopedDataPipeProducerHandle producer_handle_;
+  mojo::Watcher pipe_watcher_;
+
+  // Only valid when data is being written to the pipe.
+  scoped_refptr<DataBuffer> media_buffer_;
+  uint32_t bytes_written_;
+
+  DISALLOW_COPY_AND_ASSIGN(MojoDataBufferWriter);
+};
+
+}  // namespace media
+
+#endif  // MEDIA_MOJO_COMMON_MOJO_DATA_BUFFER_CONVERTER_