src/cobalt/media/base/shell_media_platform.h

// Copyright 2012 Google Inc. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#ifndef COBALT_MEDIA_BASE_SHELL_MEDIA_PLATFORM_H_
#define COBALT_MEDIA_BASE_SHELL_MEDIA_PLATFORM_H_

#include "base/basictypes.h"
#include "base/logging.h"
#include "base/memory/ref_counted.h"
#include "cobalt/media/base/decoder_buffer.h"
#include "cobalt/media/base/limits.h"
#include "cobalt/media/base/media_export.h"
#include "cobalt/media/base/shell_video_frame_provider.h"
#include "cobalt/render_tree/resource_provider.h"
#include "starboard/decode_target.h"

namespace cobalt {
namespace media {

// This class is meant to be the single point to attach platform specific media
// classes and settings. Each platform should implement its own implementation
// and provide it through ShellMediaPlatform::Instance.
class MEDIA_EXPORT ShellMediaPlatform {
 public:
  ShellMediaPlatform() {}
  virtual ~ShellMediaPlatform() {}

  // Individual platforms should implement the following two functions to
  // ensure that a valid ShellMediaPlatform instance is available during the
  // life time of media stack
  static void Initialize();
  static void Terminate();

  static ShellMediaPlatform* Instance();

  // The following functions will be called when the application enters or
  // leaves suspending status.
  virtual void Suspend() {}
  virtual void Resume(render_tree::ResourceProvider* /*resource_provider*/) {}

  // Media stack buffer allocate/free functions currently only used by
  // ShellBufferFactory.
  virtual void* AllocateBuffer(size_t size) = 0;
  virtual void FreeBuffer(void* ptr) = 0;

  // The maximum audio and video buffer size used by SourceBufferStream.
  // See implementation of SourceBufferStream for more details.
  virtual size_t GetSourceBufferStreamAudioMemoryLimit() const = 0;
  virtual size_t GetSourceBufferStreamVideoMemoryLimit() const = 0;

  virtual scoped_refptr<ShellVideoFrameProvider> GetVideoFrameProvider() {
    return NULL;
  }

  virtual SbDecodeTargetGraphicsContextProvider*
  GetSbDecodeTargetGraphicsContextProvider() {
    return NULL;
  }

  // This function is called before the decoder buffer leaves the demuxer and
  // is being sent to the media pipeline for decrypting and decoding. The
  // default implementation simply returns the buffer indicateing that there is
  // no processing necessary.
  virtual scoped_refptr<DecoderBuffer> ProcessBeforeLeavingDemuxer(
      const scoped_refptr<DecoderBuffer>& buffer) {
    return buffer;
  }

 protected:
  static void SetInstance(ShellMediaPlatform* shell_media_platform);

 private:
  // Platform specific media Init and Tear down.
  virtual void InternalInitialize() {}
  virtual void InternalTerminate() {}

  DISALLOW_COPY_AND_ASSIGN(ShellMediaPlatform);
};

}  // namespace media
}  // namespace cobalt

#define REGISTER_SHELL_MEDIA_PLATFORM(ClassName) \
  namespace cobalt {                             \
  namespace media {                              \
  void ShellMediaPlatform::Initialize() {        \
    DCHECK(!Instance());                         \
    SetInstance(new ClassName);                  \
    Instance()->InternalInitialize();            \
  }                                              \
  void ShellMediaPlatform::Terminate() {         \
    DCHECK(Instance());                          \
    Instance()->InternalTerminate();             \
    delete Instance();                           \
    SetInstance(NULL);                           \
  }                                              \
  }                                              \
  }

#endif  // COBALT_MEDIA_BASE_SHELL_MEDIA_PLATFORM_H_