blob: fc5f350db2ed00df09f8cd31257b833f1ff3d877 [file] [log] [blame]
* Copyright (c) 2022 The WebRTC project authors. All Rights Reserved.
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
#include "api/task_queue/task_queue_base.h"
#include "api/units/time_delta.h"
#include "rtc_base/system/rtc_export.h"
namespace webrtc {
// The Metronome posts OnTick() on task queues provided by its listeners' task
// queue periodically. The metronome can be used as an alternative to using
// PostDelayedTask on a thread or task queue for coalescing work and reducing
// the number of idle-wakeups.
// Listeners can be added and removed from any sequence, but it is illegal to
// remove a listener from an OnTick invocation.
// The metronome concept is still under experimentation, and may not be availble
// in all platforms or applications. See for more
// details.
// Metronome implementations must be thread-safe.
class RTC_EXPORT Metronome {
class RTC_EXPORT TickListener {
virtual ~TickListener() = default;
// OnTick is run on the task queue provided by OnTickTaskQueue each time the
// metronome ticks.
virtual void OnTick() = 0;
// The task queue that OnTick will run on. Must not be null.
virtual TaskQueueBase* OnTickTaskQueue() = 0;
virtual ~Metronome() = default;
// Adds a tick listener to the metronome. Once this method has returned
// OnTick will be invoked on each metronome tick. A listener may
// only be added to the metronome once.
virtual void AddListener(TickListener* listener) = 0;
// Removes the tick listener from the metronome. Once this method has returned
// OnTick will never be called again. This method must not be called from
// within OnTick.
virtual void RemoveListener(TickListener* listener) = 0;
// Returns the current tick period of the metronome.
virtual TimeDelta TickPeriod() const = 0;
} // namespace webrtc