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/*
* Copyright (C) 2020, 2021 Metrological Group B.V.
* Copyright (C) 2020, 2021 Igalia, S.L
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * 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.
* * Neither the name of Google Inc. 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 THE COPYRIGHT HOLDERS AND 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 THE COPYRIGHT
* OWNER OR 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.
*/
#pragma once
#if ENABLE(MEDIA_SOURCE) && USE(GSTREAMER)
#include "GStreamerCommon.h"
#include <functional>
#include <wtf/Deque.h>
namespace WebCore {
class TrackQueue {
public:
TrackQueue(AtomString trackId);
typedef std::function<void(GRefPtr<GstMiniObject>&&)> NotEmptyHandler;
typedef std::function<void()> LowLevelHandler;
// Note: The TrackQueue methods are not thread-safe. TrackQueue must always be wrapped in a DataMutex<>.
// For producer thread (main-thread):
void enqueueObject(GRefPtr<GstMiniObject>&&);
bool isFull() const { return durationEnqueued() >= s_durationEnqueuedHighWaterLevel; }
void notifyWhenLowLevel(LowLevelHandler&&);
void clear();
void flush();
// For consumer thread:
bool isEmpty() const { return m_queue.isEmpty(); }
GRefPtr<GstMiniObject> pop();
void notifyWhenNotEmpty(NotEmptyHandler&&);
bool hasNotEmptyHandler() const { return m_notEmptyCallback != nullptr; }
void resetNotEmptyHandler();
private:
// The point of having a queue for WebKitMediaSource is to limit the number of context switches per second.
// If we had no queue, the main thread would have to be awaken for every frame. On the other hand, if the
// queue had unlimited size WebKit would end up requesting flushes more often than necessary when frames
// in the future are re-appended. As a sweet spot between these extremes we choose to allow enqueueing a
// few seconds worth of samples.
// `isReadyForMoreSamples` follows the classical two water levels strategy: initially it's true until the
// high water level is reached, then it becomes false until the queue drains down to the low water level
// and the cycle repeats. This way we avoid stalls and minimize context switches.
static const GstClockTime s_durationEnqueuedHighWaterLevel = 5 * GST_SECOND;
static const GstClockTime s_durationEnqueuedLowWaterLevel = 2 * GST_SECOND;
GstClockTime durationEnqueued() const;
void checkLowLevel();
AtomString m_trackId;
Deque<GRefPtr<GstMiniObject>> m_queue;
LowLevelHandler m_lowLevelCallback;
NotEmptyHandler m_notEmptyCallback;
};
}
#endif
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