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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this file,
* You can obtain one at */
#ifndef mozilla_dom_mediaplaybackdelaypolicy_h__
#define mozilla_dom_mediaplaybackdelaypolicy_h__
#include "AudioChannelAgent.h"
#include "AudioChannelService.h"
#include "mozilla/MozPromise.h"
#include "mozilla/RefPtr.h"
#include "nsISupportsImpl.h"
typedef uint32_t SuspendTypes;
namespace mozilla {
namespace dom {
class HTMLMediaElement;
* We usaually start AudioChannelAgent when media starts and stop it when media
* stops. However, when we decide to delay media playback for unvisited tab, we
* would start AudioChannelAgent even if media doesn't start in order to
* register the agent to AudioChannelService, so that the service could notify
* us when we are able to resume media playback. Therefore,
* ResumeDelayedPlaybackAgent is used to handle this special use case of
* AudioChannelAgent.
* - Use `GetResumePromise()` to require resume-promise and then do follow-up
* resume behavior when promise is resolved.
* - Use `UpdateAudibleState()` to update audible state only when media info
* changes. As having audio track or not is the only thing for us to decide
* whether we would show the delayed media playback icon on the tab bar.
class ResumeDelayedPlaybackAgent {
ResumeDelayedPlaybackAgent() = default;
using ResumePromise = MozPromise<bool, bool, true /* IsExclusive */>;
RefPtr<ResumePromise> GetResumePromise();
void UpdateAudibleState(const HTMLMediaElement* aElement, bool aIsAudible);
friend class MediaPlaybackDelayPolicy;
bool InitDelegate(const HTMLMediaElement* aElement, bool aIsAudible);
class ResumePlayDelegate final : public nsIAudioChannelAgentCallback {
ResumePlayDelegate() = default;
bool Init(const HTMLMediaElement* aElement, bool aIsAudible);
void UpdateAudibleState(const HTMLMediaElement* aElement, bool aIsAudible);
RefPtr<ResumePromise> GetResumePromise();
void Clear();
NS_IMETHODIMP WindowVolumeChanged(float aVolume, bool aMuted) override;
NS_IMETHODIMP WindowAudioCaptureChanged(bool aCapture) override;
NS_IMETHODIMP WindowSuspendChanged(SuspendTypes aSuspend) override;
virtual ~ResumePlayDelegate();
MozPromiseHolder<ResumePromise> mPromise;
RefPtr<AudioChannelAgent> mAudioChannelAgent;
RefPtr<ResumePlayDelegate> mDelegate;
class MediaPlaybackDelayPolicy {
static bool ShouldDelayPlayback(const HTMLMediaElement* aElement);
static RefPtr<ResumeDelayedPlaybackAgent> CreateResumeDelayedPlaybackAgent(
const HTMLMediaElement* aElement, bool aIsAudible);
} // namespace dom
} // namespace mozilla