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// 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.
#include <list>
#include <string>
#include "base/callback.h"
#include "base/macros.h"
#include "base/memory/ref_counted.h"
#include "base/memory/weak_ptr.h"
#include "base/threading/thread_checker.h"
#include "base/time/time.h"
namespace chromecast {
namespace media {
class BufferingConfig;
class BufferingState;
class BufferingController {
typedef base::Callback<void(bool)> BufferingNotificationCB;
// Creates a buffering controller where the conditions to trigger rebuffering
// are given by |config|. The whole point of the buffering controller is to
// derive a single buffering state from the buffering state of various
// streams.
// |buffering_notification_cb| is a callback invoked to inform about possible
// changes of the buffering state.
const scoped_refptr<BufferingConfig>& config,
const BufferingNotificationCB& buffering_notification_cb);
// Creates a buffering state for one stream. This state is added to the list
// of streams monitored by the buffering controller.
scoped_refptr<BufferingState> AddStream(const std::string& stream_id);
// Sets the playback time.
void SetMediaTime(base::TimeDelta time);
// Returns the maximum media time available for rendering.
// Return kNoTimestamp() if unknown.
base::TimeDelta GetMaxRenderingTime() const;
// Returns whether there is an active buffering phase.
bool IsBuffering() const { return is_buffering_; }
// Resets the buffering controller. This includes removing all the streams
// that were previously added.
void Reset();
// Invoked each time the buffering state of one of the streams has changed.
// If |force_notification| is set, |buffering_notification_cb_| is invoked
// regardless whether the buffering state has changed or not.
// If |buffering_timeout| is set, then the condition to leave the buffering
// state is relaxed (we don't want to wait more).
void OnBufferingStateChanged(bool force_notification,
bool buffering_timeout);
// Updates the high buffer level threshold to |high_level_threshold|
// if needed.
// This condition is triggered when one of the stream reached its maximum
// capacity. In that case, to avoid possible race condition (the buffering
// controller waits for more data to come but the buffer is to small to
// accomodate additional data), the thresholds in |config_| are adjusted
// accordingly.
void UpdateHighLevelThreshold(base::TimeDelta high_level_threshold);
// Determines the overall buffer level based on the buffer level of each
// stream.
bool IsHighBufferLevel();
bool IsLowBufferLevel();
// Logs the state of the buffering controller.
void DumpState() const;
base::ThreadChecker thread_checker_;
// Settings used to determine when to start/stop buffering.
scoped_refptr<BufferingConfig> config_;
// Callback invoked each time there is a change of the buffering state.
BufferingNotificationCB buffering_notification_cb_;
// State of the buffering controller.
bool is_buffering_;
// Start time of a re-buffering phase.
base::Time begin_buffering_time_;
base::Time last_buffer_end_time_;
bool initial_buffering_;
// Buffering level for each individual stream.
typedef std::list<scoped_refptr<BufferingState> > StreamList;
StreamList stream_list_;
base::WeakPtr<BufferingController> weak_this_;
base::WeakPtrFactory<BufferingController> weak_factory_;
} // namespace media
} // namespace chromecast