gecko-dev/dom/audiochannel/nsIAudioChannelAgent.idl

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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 http://mozilla.org/MPL/2.0/. */
#include "nsISupports.idl"
[function, scriptable, uuid(c7227506-5f8e-11e2-8bb3-10bf48d64bd4)]
interface nsIAudioChannelAgentCallback : nsISupports
{
/**
* Notified when the playable status of channel is changed.
*
* @param canPlay
* Callback from agent to notify component of the playable status
* of the channel. If canPlay is muted state, component SHOULD stop
* playing media associated with this channel as soon as possible. if
* it is faded state then the volume of media should be reduced.
*/
void canPlayChanged(in long canPlay);
};
/**
* This interface provides an agent for gecko components to participate
* in the audio channel service. Gecko components are responsible for
* 1. Indicating what channel type they are using (via the init() member function).
* 2. Before playing, checking the playable status of the channel.
* 3. Notifying the agent when they start/stop using this channel.
* 4. Notifying the agent of changes to the visibility of the component using
* this channel.
*
* The agent will invoke a callback to notify Gecko components of
* 1. Changes to the playable status of this channel.
*/
[scriptable, uuid(86ef883d-9cec-4c04-994f-5de198286e7c)]
interface nsIAudioChannelAgent : nsISupports
{
const long AUDIO_AGENT_CHANNEL_NORMAL = 0;
const long AUDIO_AGENT_CHANNEL_CONTENT = 1;
const long AUDIO_AGENT_CHANNEL_NOTIFICATION = 2;
const long AUDIO_AGENT_CHANNEL_ALARM = 3;
const long AUDIO_AGENT_CHANNEL_TELEPHONY = 4;
const long AUDIO_AGENT_CHANNEL_RINGER = 5;
const long AUDIO_AGENT_CHANNEL_PUBLICNOTIFICATION = 6;
const long AUDIO_AGENT_CHANNEL_ERROR = 1000;
const long AUDIO_AGENT_STATE_NORMAL = 0;
const long AUDIO_AGENT_STATE_MUTED = 1;
const long AUDIO_AGENT_STATE_FADED = 2;
/**
* Before init() is called, this returns AUDIO_AGENT_CHANNEL_ERROR.
*/
readonly attribute long audioChannelType;
/**
* Initialize the agent with a channel type.
* Note: This function should only be called once.
*
* @param channelType
* Audio Channel Type listed as above
* @param callback
* 1. Once the playable status changes, agent uses this callback function to notify
* Gecko component.
* 2. The callback is allowed to be null. Ex: telephony doesn't need to listen change
* of the playable status.
* 3. The AudioChannelAgent keeps a strong reference to the callback object.
*/
void init(in long channelType, in nsIAudioChannelAgentCallback callback);
/**
* This method is just like init(), except the audio channel agent keeps a
* weak reference to the callback object.
*
* In order for this to work, |callback| must implement
* nsISupportsWeakReference.
*/
void initWithWeakCallback(in long channelType, in nsIAudioChannelAgentCallback callback);
/**
* This method is just like init(), and specify the channel is associated with video.
*
* @param weak
* true if weak reference should be hold.
*/
void initWithVideo(in long channelType, in nsIAudioChannelAgentCallback callback, in boolean weak);
/**
* Notify the agent that we want to start playing.
* Note: Gecko component SHOULD call this function first then start to
* play audio stream only when return value is true.
*
*
* @return
* normal state: the agent has registered with audio channel service and
* the component should start playback.
* muted state: the agent has registered with audio channel service but
* the component should not start playback.
* faded state: the agent has registered with audio channel service the
* component should start playback as well as reducing the volume.
*/
long startPlaying();
/**
* Notify the agent we no longer want to play.
*
* Note : even if startPlaying() returned false, the agent would still be
* registered with the audio channel service and receive callbacks for status changes.
* So stopPlaying must still eventually be called to unregister the agent with the
* channel service.
*/
void stopPlaying();
/**
* Notify the agent of the visibility state of the window using this agent.
* @param visible
* True if the window associated with the agent is visible.
*/
void setVisibilityState(in boolean visible);
};