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/* 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 */
#include "mozilla/AlreadyAddRefed.h"
#include "AudioFocusManager.h"
#include "MediaController.h"
#include "MediaControlKeyManager.h"
#include "mozilla/dom/MediaControllerBinding.h"
#include "nsIObserver.h"
#include "nsTArray.h"
namespace mozilla {
namespace dom {
* MediaControlService is an interface to access controllers by providing
* controller Id. Everytime when controller becomes active, which means there is
* one or more media started in the corresponding browsing context, so now the
* controller is actually controlling something in the content process, so it
* would be added into the list of the MediaControlService. The controller would
* be removed from the list of the MediaControlService when it becomes inactive,
* which means no media is playing in the corresponding browsing context. Note
* that, a controller can't be added to or remove from the list twice. It should
* should have a responsibility to add and remove itself in the proper time.
class MediaControlService final : public nsIObserver {
static RefPtr<MediaControlService> GetService();
// Currently these following static methods are only being used in testing.
static void GenerateMediaControlKey(const GlobalObject& global,
MediaControlKey aKey);
static void GetCurrentActiveMediaMetadata(const GlobalObject& aGlobal,
MediaMetadataInit& aMetadata);
static MediaSessionPlaybackState GetCurrentMediaSessionPlaybackState(
GlobalObject& aGlobal);
AudioFocusManager& GetAudioFocusManager() { return mAudioFocusManager; }
MediaControlKeySource* GetMediaControlKeySource() {
return mMediaControlKeyManager;
// Use these functions to register/unresgister controller to/from the active
// controller list in the service. Return true if the controller is registered
// or unregistered sucessfully.
bool RegisterActiveMediaController(MediaController* aController);
bool UnregisterActiveMediaController(MediaController* aController);
uint64_t GetActiveControllersNum() const;
// This method would be called when the controller changes its playback state.
void NotifyControllerPlaybackStateChanged(MediaController* aController);
// This method is used to help a media controller become a main controller, if
// it fits the requirement.
void RequestUpdateMainController(MediaController* aController);
// The main controller is the controller which can receive the media control
// key events and would show its metadata to virtual controller interface.
MediaController* GetMainController() const;
* These following functions are used for testing only. We use them to
* generate fake media control key events, get the media metadata and playback
* state from the main controller.
void GenerateTestMediaControlKey(MediaControlKey aKey);
MediaMetadataBase GetMainControllerMediaMetadata() const;
MediaSessionPlaybackState GetMainControllerPlaybackState() const;
// Media title that should be used as a fallback. This commonly used
// when playing media in private browsing mode and we are trying to avoid
// exposing potentially sensitive titles.
nsString GetFallbackTitle() const;
// These functions are used to update the variable which would be used for
// telemetry probe.
void NotifyMediaControlHasEverBeenUsed();
void NotifyMediaControlHasEverBeenEnabled();
* When there are multiple media controllers existing, we would only choose
* one media controller as the main controller which can be controlled by
* media control keys event. The latest controller which is added into the
* service would become the main controller.
* However, as the main controller would be changed from time to time, so we
* create this wrapper to hold a real main controller if it exists. This class
* would also observe the playback state of controller in order to update the
* playback state of the event source.
* In addition, after finishing bug1592037, we would get the media metadata
* from the main controller, and update them to the event source in order to
* show those information on the virtual media controller interface on each
* platform.
class ControllerManager final {
explicit ControllerManager(MediaControlService* aService);
~ControllerManager() = default;
using MediaKeysArray = nsTArray<MediaControlKey>;
using LinkedListControllerPtr = LinkedListElement<RefPtr<MediaController>>*;
using ConstLinkedListControllerPtr =
const LinkedListElement<RefPtr<MediaController>>*;
bool AddController(MediaController* aController);
bool RemoveController(MediaController* aController);
void UpdateMainControllerIfNeeded(MediaController* aController);
void Shutdown();
MediaController* GetMainController() const;
bool Contains(MediaController* aController) const;
uint64_t GetControllersNum() const;
// These functions are used for monitoring main controller's status change.
void MainControllerPlaybackStateChanged(MediaSessionPlaybackState aState);
void MainControllerMetadataChanged(const MediaMetadataBase& aMetadata);
// When applying `eInsertAsMainController`, we would always insert the
// element to the tail of the list. Eg. Insert C , [A, B] -> [A, B, C]
// When applying `eInsertAsNormalController`, we would insert the element
// prior to the element with a higher priority controller. Eg. Insert E and
// C and D have higher priority. [A, B, C, D] -> [A, B, E, C, D]
enum class InsertOptions {
// Adjust the given controller's order by the insert option.
void ReorderGivenController(MediaController* aController,
InsertOptions aOption);
void UpdateMainControllerInternal(MediaController* aController);
void ConnectMainControllerEvents();
void DisconnectMainControllerEvents();
LinkedList<RefPtr<MediaController>> mControllers;
RefPtr<MediaController> mMainController;
// These member are use to listen main controller's play state changes and
// update the playback state to the event source.
RefPtr<MediaControlKeySource> mSource;
MediaEventListener mMetadataChangedListener;
MediaEventListener mSupportedKeysChangedListener;
MediaEventListener mFullScreenChangedListener;
MediaEventListener mPictureInPictureModeChangedListener;
MediaEventListener mPositionChangedListener;
void Init();
void Shutdown();
AudioFocusManager mAudioFocusManager;
RefPtr<MediaControlKeyManager> mMediaControlKeyManager;
RefPtr<MediaControlKeyListener> mMediaKeysHandler;
MediaEventProducer<uint64_t> mMediaControllerAmountChangedEvent;
UniquePtr<ControllerManager> mControllerManager;
nsString mFallbackTitle;
// Used for telemetry probe.
void UpdateTelemetryUsageProbe();
bool mHasEverUsedMediaControl = false;
bool mHasEverEnabledMediaControl = false;
} // namespace dom
} // namespace mozilla