Load CMA backend from shared library

chromecast/media/cma/backend/media_component_device.h

-// Copyright 2014 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 CHROMECAST_MEDIA_CMA_BACKEND_MEDIA_COMPONENT_DEVICE_H_
-#define CHROMECAST_MEDIA_CMA_BACKEND_MEDIA_COMPONENT_DEVICE_H_
-
-#include <string>
-
-#include "base/basictypes.h"
-#include "base/callback.h"
-#include "base/macros.h"
-#include "base/memory/ref_counted.h"
-#include "base/threading/non_thread_safe.h"
-#include "base/time/time.h"
-
-namespace chromecast {
-namespace media {
-class DecoderBufferBase;
-class DecryptContext;
-
-// MediaComponentDevice -
-//
-// State machine:
-//                       -------------- kRunning <---
-//                       |                 ^        |
-//                       v                 |        |
-// kUninitialized <--> kIdle  --------------        |
-//                       ^                 |        |
-//                       |                 v        |
-//                       -------------- kPaused <----
-// {any state} --> kError
-// kError --> kUninitialized
-//
-// Notes:
-// - Hardware resources are acquired when transitioning from the
-//   |kUninitialized| state to the |kIdle| state.
-// - Buffers can be pushed only in the kRunning or kPaused states.
-// - The end of stream is signaled through a special buffer.
-//   Once the end of stream buffer is fed, no other buffer
-//   can be fed until the FSM goes through the kIdle state again.
-// - In both kPaused and kRunning states, frames can be fed.
-//   However, frames are possibly rendered only in the kRunning state.
-// - In the kRunning state, frames are rendered according to the clock rate.
-// - All the hardware resources must be released in the |kError| state.
-//
-class MediaComponentDevice
-    : NON_EXPORTED_BASE(public base::NonThreadSafe) {
- public:
-  enum State {
-    kStateUninitialized,
-    kStateIdle,
-    kStateRunning,
-    kStatePaused,
-    kStateError,
-  };
-
-  enum FrameStatus {
-    kFrameSuccess,
-    kFrameFailed,
-    kFramePending,
-  };
-  typedef base::Callback<void(FrameStatus)> FrameStatusCB;
-
-  struct Client {
-    Client();
-    ~Client();
-
-    // Invoked when playback reaches the end of stream.
-    base::Closure eos_cb;
-  };
-
-  // The statistics are computed since the media component left the idle state.
-  // For video, a sample is defined as a frame.
-  struct Statistics {
-    uint64 decoded_bytes;
-    uint64 decoded_samples;
-    uint64 dropped_samples;
-  };
-
-  // Returns whether or not transitioning from |state1| to |state2| is valid.
-  static bool IsValidStateTransition(State state1, State state2);
-
-  // Returns string representation of state (for logging)
-  static std::string StateToString(const State& state);
-
-  MediaComponentDevice();
-  virtual ~MediaComponentDevice();
-
-  // Register |client| as the media event handler.
-  virtual void SetClient(const Client& client) = 0;
-
-  // Changes the state and performs any necessary transitions.
-  // Returns true when successful.
-  virtual bool SetState(State new_state) = 0;
-
-  // Returns the current state of the media component.
-  virtual State GetState() const = 0;
-
-  // Sets the time where rendering should start.
-  // Return true when successful.
-  // Can only be invoked in state kStateIdle.
-  virtual bool SetStartPts(base::TimeDelta time) = 0;
-
-  // Pushes a frame.
-  // |completion_cb| is only invoked if the returned value is |kFramePending|.
-  // In this specific case, no additional frame can be pushed before
-  // |completion_cb| is invoked.
-  // Note: |completion_cb| cannot be invoked with |kFramePending|.
-  // Note: pushing the pending frame should be aborted when the state goes back
-  // to kStateIdle. |completion_cb| is not invoked in that case.
-  virtual FrameStatus PushFrame(
-      const scoped_refptr<DecryptContext>& decrypt_context,
-      const scoped_refptr<DecoderBufferBase>& buffer,
-      const FrameStatusCB& completion_cb) = 0;
-
-  // Returns the rendering time of the latest rendered sample.
-  // Can be invoked only in states kStateRunning or kStatePaused.
-  // Returns |kNoTimestamp()| if the playback time cannot be retrieved.
-  virtual base::TimeDelta GetRenderingTime() const = 0;
-
-  // Returns the pipeline latency: i.e. the amount of data
-  // in the pipeline that have not been rendered yet.
-  // Returns |kNoTimestamp()| if the latency is not available.
-  virtual base::TimeDelta GetRenderingDelay() const = 0;
-
-  // Returns the playback statistics. Statistics are computed since the media
-  // component left the idle state.
-  // Returns true when successful.
-  // Can only be invoked in state kStateRunning.
-  virtual bool GetStatistics(Statistics* stats) const = 0;
-
- private:
-  DISALLOW_COPY_AND_ASSIGN(MediaComponentDevice);
-};
-
-}  // namespace media
-}  // namespace chromecast
-
-#endif  // CHROMECAST_MEDIA_CMA_BACKEND_MEDIA_COMPONENT_DEVICE_H_