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/*
* Copyright (C) 2012 Google Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of Apple Computer, Inc. ("Apple") nor the names of
* its contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef THIRD_PARTY_BLINK_RENDERER_MODULES_WEBAUDIO_AUDIO_SCHEDULED_SOURCE_NODE_H_
#define THIRD_PARTY_BLINK_RENDERER_MODULES_WEBAUDIO_AUDIO_SCHEDULED_SOURCE_NODE_H_
#include <atomic>
#include "base/memory/weak_ptr.h"
#include "third_party/blink/renderer/bindings/core/v8/active_script_wrappable.h"
#include "third_party/blink/renderer/modules/webaudio/audio_node.h"
namespace blink {
class BaseAudioContext;
class AudioBus;
class AudioScheduledSourceHandler
: public AudioHandler,
public base::SupportsWeakPtr<AudioScheduledSourceHandler> {
public:
// These are the possible states an AudioScheduledSourceNode can be in:
//
// UNSCHEDULED_STATE - Initial playback state. Created, but not yet scheduled.
// SCHEDULED_STATE - Scheduled to play (via start()), but not yet playing.
// PLAYING_STATE - Generating sound.
// FINISHED_STATE - Finished generating sound.
//
// The state can only transition to the next state, except for the
// FINISHED_STATE which can never be changed.
enum PlaybackState {
// These must be defined with the same names and values as in the .idl file.
UNSCHEDULED_STATE = 0,
SCHEDULED_STATE = 1,
PLAYING_STATE = 2,
FINISHED_STATE = 3
};
AudioScheduledSourceHandler(NodeType, AudioNode&, float sample_rate);
// Scheduling.
void Start(double when, ExceptionState&);
void Stop(double when, ExceptionState&);
// AudioNode
double TailTime() const override { return 0; }
double LatencyTime() const override { return 0; }
PlaybackState GetPlaybackState() const {
return playback_state_.load(std::memory_order_acquire);
}
void SetPlaybackState(PlaybackState new_state) {
playback_state_.store(new_state, std::memory_order_release);
}
bool IsPlayingOrScheduled() const {
PlaybackState state = GetPlaybackState();
return state == PLAYING_STATE || state == SCHEDULED_STATE;
}
bool HasFinished() const { return GetPlaybackState() == FINISHED_STATE; }
// Source nodes don't have tail or latency times so no tail
// processing needed.
bool RequiresTailProcessing() const final { return false; }
// Stops a node if the stop time has passed. Generally used when a source
// node has been scheduled to start but has disconnected some time before the
// stop time has arrived. Nodes that are not reachable from the destination
// don't progress in time so we need to handle this specially.
virtual void HandleStoppableSourceNode() = 0;
protected:
// Get frame information for the current time quantum.
// We handle the transition into PLAYING_STATE and FINISHED_STATE here,
// zeroing out portions of the outputBus which are outside the range of
// startFrame and endFrame.
//
// Each frame time is relative to the context's currentSampleFrame(). Three
// values are returned, in this order:
//
// quantumFrameOffset : Offset frame in this time quantum to start
// rendering.
// nonSilentFramesToProcess : Number of frames rendering non-silence (will be
// <= quantumFrameSize).
// startFrameOffset : The fractional frame offset from quantumFrameOffset
// and the actual starting time of the source. This is
// non-zero only when transitioning from the
// SCHEDULED_STATE to the PLAYING_STATE.
//
// Callers should check nonSilentFramesToProcess to decide what to
// do. If it is zero, the other return values are meaningless.
std::tuple<size_t, size_t, double> UpdateSchedulingInfo(
size_t quantum_frame_size,
AudioBus* output_bus);
// Called when we have no more sound to play or the stop() time has been
// reached. No onEnded event is called.
virtual void FinishWithoutOnEnded();
// Like finishWithoutOnEnded(), but an onEnded (if specified) is called.
virtual void Finish();
void NotifyEnded();
// This synchronizes with process() and any other method that needs to be
// synchronized like setBuffer for AudioBufferSource.
mutable Mutex process_lock_;
// m_startTime is the time to start playing based on the context's timeline (0
// or a time less than the context's current time means "now").
double start_time_; // in seconds
// m_endTime is the time to stop playing based on the context's timeline (0 or
// a time less than the context's current time means "now"). If it hasn't
// been set explicitly, then the sound will not stop playing (if looping) or
// will stop when the end of the AudioBuffer has been reached.
double end_time_; // in seconds
// Magic value indicating that the time (start or end) has not yet been set.
static const double kUnknownTime;
// Number of extra frames to use when determining if a source node can be
// stopped. This should be at least one rendering quantum, but we add one
// more quantum for good measure. This doesn't need to be extra precise, just
// more than one rendering quantum. See |handleStoppableSourceNode()|.
// FIXME: Expose the rendering quantum somehow instead of hardwiring a value
// here.
static const int kExtraStopFrames = 256;
private:
// This is accessed by both the main thread and audio thread. Use the setter
// and getter to protect the access to this.
std::atomic<PlaybackState> playback_state_;
scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
};
class AudioScheduledSourceNode
: public AudioNode,
public ActiveScriptWrappable<AudioScheduledSourceNode> {
USING_GARBAGE_COLLECTED_MIXIN(AudioScheduledSourceNode);
DEFINE_WRAPPERTYPEINFO();
public:
void start(ExceptionState&);
void start(double when, ExceptionState&);
void stop(ExceptionState&);
void stop(double when, ExceptionState&);
EventListener* onended();
void setOnended(EventListener*);
// ScriptWrappable:
bool HasPendingActivity() const final;
void Trace(blink::Visitor* visitor) override { AudioNode::Trace(visitor); }
AudioScheduledSourceHandler& GetAudioScheduledSourceHandler() const;
protected:
explicit AudioScheduledSourceNode(BaseAudioContext&);
};
} // namespace blink
#endif // THIRD_PARTY_BLINK_RENDERER_MODULES_WEBAUDIO_AUDIO_SCHEDULED_SOURCE_NODE_H_
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