chore: monorepo setup (#7175)

2026-03-16 19:43:29 +01:00 · 2022-01-07 17:18:25 +01:00
parent 780b7ed39f
commit 16390efe6e
504 changed files with 25459 additions and 22830 deletions
--- a/packages/voice/src/audio/AudioPlayer.ts
+++ b/packages/voice/src/audio/AudioPlayer.ts
@@ -0,0 +1,627 @@
+import { addAudioPlayer, deleteAudioPlayer } from '../DataStore';
+import { Awaited, noop } from '../util/util';
+import { VoiceConnection, VoiceConnectionStatus } from '../VoiceConnection';
+import { AudioPlayerError } from './AudioPlayerError';
+import type { AudioResource } from './AudioResource';
+import { PlayerSubscription } from './PlayerSubscription';
+import { TypedEmitter } from 'tiny-typed-emitter';
+
+// The Opus "silent" frame
+export const SILENCE_FRAME = Buffer.from([0xf8, 0xff, 0xfe]);
+
+/**
+ * Describes the behavior of the player when an audio packet is played but there are no available
+ * voice connections to play to.
+ */
+export enum NoSubscriberBehavior {
+	/**
+	 * Pauses playing the stream until a voice connection becomes available.
+	 */
+	Pause = 'pause',
+
+	/**
+	 * Continues to play through the resource regardless.
+	 */
+	Play = 'play',
+
+	/**
+	 * The player stops and enters the Idle state.
+	 */
+	Stop = 'stop',
+}
+
+export enum AudioPlayerStatus {
+	/**
+	 * When there is currently no resource for the player to be playing.
+	 */
+	Idle = 'idle',
+
+	/**
+	 * When the player is waiting for an audio resource to become readable before transitioning to Playing.
+	 */
+	Buffering = 'buffering',
+
+	/**
+	 * When the player has been manually paused.
+	 */
+	Paused = 'paused',
+
+	/**
+	 * When the player is actively playing an audio resource.
+	 */
+	Playing = 'playing',
+
+	/**
+	 * When the player has paused itself. Only possible with the "pause" no subscriber behavior.
+	 */
+	AutoPaused = 'autopaused',
+}
+
+/**
+ * Options that can be passed when creating an audio player, used to specify its behavior.
+ */
+export interface CreateAudioPlayerOptions {
+	debug?: boolean;
+	behaviors?: {
+		noSubscriber?: NoSubscriberBehavior;
+		maxMissedFrames?: number;
+	};
+}
+
+/**
+ * The state that an AudioPlayer is in when it has no resource to play. This is the starting state.
+ */
+export interface AudioPlayerIdleState {
+	status: AudioPlayerStatus.Idle;
+}
+
+/**
+ * The state that an AudioPlayer is in when it is waiting for a resource to become readable. Once this
+ * happens, the AudioPlayer will enter the Playing state. If the resource ends/errors before this, then
+ * it will re-enter the Idle state.
+ */
+export interface AudioPlayerBufferingState {
+	status: AudioPlayerStatus.Buffering;
+	/**
+	 * The resource that the AudioPlayer is waiting for
+	 */
+	resource: AudioResource;
+	onReadableCallback: () => void;
+	onFailureCallback: () => void;
+	onStreamError: (error: Error) => void;
+}
+
+/**
+ * The state that an AudioPlayer is in when it is actively playing an AudioResource. When playback ends,
+ * it will enter the Idle state.
+ */
+export interface AudioPlayerPlayingState {
+	status: AudioPlayerStatus.Playing;
+	/**
+	 * The number of consecutive times that the audio resource has been unable to provide an Opus frame.
+	 */
+	missedFrames: number;
+
+	/**
+	 * The playback duration in milliseconds of the current audio resource. This includes filler silence packets
+	 * that have been played when the resource was buffering.
+	 */
+	playbackDuration: number;
+
+	/**
+	 * The resource that is being played.
+	 */
+	resource: AudioResource;
+
+	onStreamError: (error: Error) => void;
+}
+
+/**
+ * The state that an AudioPlayer is in when it has either been explicitly paused by the user, or done
+ * automatically by the AudioPlayer itself if there are no available subscribers.
+ */
+export interface AudioPlayerPausedState {
+	status: AudioPlayerStatus.Paused | AudioPlayerStatus.AutoPaused;
+	/**
+	 * How many silence packets still need to be played to avoid audio interpolation due to the stream suddenly pausing.
+	 */
+	silencePacketsRemaining: number;
+
+	/**
+	 * The playback duration in milliseconds of the current audio resource. This includes filler silence packets
+	 * that have been played when the resource was buffering.
+	 */
+	playbackDuration: number;
+
+	/**
+	 * The current resource of the audio player.
+	 */
+	resource: AudioResource;
+
+	onStreamError: (error: Error) => void;
+}
+
+/**
+ * The various states that the player can be in.
+ */
+export type AudioPlayerState =
+	| AudioPlayerIdleState
+	| AudioPlayerBufferingState
+	| AudioPlayerPlayingState
+	| AudioPlayerPausedState;
+
+export type AudioPlayerEvents = {
+	error: (error: AudioPlayerError) => Awaited<void>;
+	debug: (message: string) => Awaited<void>;
+	stateChange: (oldState: AudioPlayerState, newState: AudioPlayerState) => Awaited<void>;
+	subscribe: (subscription: PlayerSubscription) => Awaited<void>;
+	unsubscribe: (subscription: PlayerSubscription) => Awaited<void>;
+} & {
+	[status in AudioPlayerStatus]: (
+		oldState: AudioPlayerState,
+		newState: AudioPlayerState & { status: status },
+	) => Awaited<void>;
+};
+
+/**
+ * Used to play audio resources (i.e. tracks, streams) to voice connections.
+ *
+ * @remarks
+ * Audio players are designed to be re-used - even if a resource has finished playing, the player itself
+ * can still be used.
+ *
+ * The AudioPlayer drives the timing of playback, and therefore is unaffected by voice connections
+ * becoming unavailable. Its behavior in these scenarios can be configured.
+ */
+export class AudioPlayer extends TypedEmitter<AudioPlayerEvents> {
+	/**
+	 * The state that the AudioPlayer is in.
+	 */
+	private _state: AudioPlayerState;
+
+	/**
+	 * A list of VoiceConnections that are registered to this AudioPlayer. The player will attempt to play audio
+	 * to the streams in this list.
+	 */
+	private readonly subscribers: PlayerSubscription[] = [];
+
+	/**
+	 * The behavior that the player should follow when it enters certain situations.
+	 */
+	private readonly behaviors: {
+		noSubscriber: NoSubscriberBehavior;
+		maxMissedFrames: number;
+	};
+
+	/**
+	 * The debug logger function, if debugging is enabled.
+	 */
+	private readonly debug: null | ((message: string) => void);
+
+	/**
+	 * Creates a new AudioPlayer.
+	 */
+	public constructor(options: CreateAudioPlayerOptions = {}) {
+		super();
+		this._state = { status: AudioPlayerStatus.Idle };
+		this.behaviors = {
+			noSubscriber: NoSubscriberBehavior.Pause,
+			maxMissedFrames: 5,
+			...options.behaviors,
+		};
+		this.debug = options.debug === false ? null : (message: string) => this.emit('debug', message);
+	}
+
+	/**
+	 * A list of subscribed voice connections that can currently receive audio to play.
+	 */
+	public get playable() {
+		return this.subscribers
+			.filter(({ connection }) => connection.state.status === VoiceConnectionStatus.Ready)
+			.map(({ connection }) => connection);
+	}
+
+	/**
+	 * Subscribes a VoiceConnection to the audio player's play list. If the VoiceConnection is already subscribed,
+	 * then the existing subscription is used.
+	 *
+	 * @remarks
+	 * This method should not be directly called. Instead, use VoiceConnection#subscribe.
+	 *
+	 * @param connection - The connection to subscribe
+	 *
+	 * @returns The new subscription if the voice connection is not yet subscribed, otherwise the existing subscription
+	 */
+	// @ts-ignore
+	private subscribe(connection: VoiceConnection) {
+		const existingSubscription = this.subscribers.find((subscription) => subscription.connection === connection);
+		if (!existingSubscription) {
+			const subscription = new PlayerSubscription(connection, this);
+			this.subscribers.push(subscription);
+			setImmediate(() => this.emit('subscribe', subscription));
+			return subscription;
+		}
+		return existingSubscription;
+	}
+
+	/**
+	 * Unsubscribes a subscription - i.e. removes a voice connection from the play list of the audio player.
+	 *
+	 * @remarks
+	 * This method should not be directly called. Instead, use PlayerSubscription#unsubscribe.
+	 *
+	 * @param subscription - The subscription to remove
+	 *
+	 * @returns Whether or not the subscription existed on the player and was removed
+	 */
+	// @ts-ignore
+	private unsubscribe(subscription: PlayerSubscription) {
+		const index = this.subscribers.indexOf(subscription);
+		const exists = index !== -1;
+		if (exists) {
+			this.subscribers.splice(index, 1);
+			subscription.connection.setSpeaking(false);
+			this.emit('unsubscribe', subscription);
+		}
+		return exists;
+	}
+
+	/**
+	 * The state that the player is in.
+	 */
+	public get state() {
+		return this._state;
+	}
+
+	/**
+	 * Sets a new state for the player, performing clean-up operations where necessary.
+	 */
+	public set state(newState: AudioPlayerState) {
+		const oldState = this._state;
+		const newResource = Reflect.get(newState, 'resource') as AudioResource | undefined;
+
+		if (oldState.status !== AudioPlayerStatus.Idle && oldState.resource !== newResource) {
+			oldState.resource.playStream.on('error', noop);
+			oldState.resource.playStream.off('error', oldState.onStreamError);
+			oldState.resource.audioPlayer = undefined;
+			oldState.resource.playStream.destroy();
+			oldState.resource.playStream.read(); // required to ensure buffered data is drained, prevents memory leak
+		}
+
+		// When leaving the Buffering state (or buffering a new resource), then remove the event listeners from it
+		if (
+			oldState.status === AudioPlayerStatus.Buffering &&
+			(newState.status !== AudioPlayerStatus.Buffering || newState.resource !== oldState.resource)
+		) {
+			oldState.resource.playStream.off('end', oldState.onFailureCallback);
+			oldState.resource.playStream.off('close', oldState.onFailureCallback);
+			oldState.resource.playStream.off('finish', oldState.onFailureCallback);
+			oldState.resource.playStream.off('readable', oldState.onReadableCallback);
+		}
+
+		// transitioning into an idle should ensure that connections stop speaking
+		if (newState.status === AudioPlayerStatus.Idle) {
+			this._signalStopSpeaking();
+			deleteAudioPlayer(this);
+		}
+
+		// attach to the global audio player timer
+		if (newResource) {
+			addAudioPlayer(this);
+		}
+
+		// playing -> playing state changes should still transition if a resource changed (seems like it would be useful!)
+		const didChangeResources =
+			oldState.status !== AudioPlayerStatus.Idle &&
+			newState.status === AudioPlayerStatus.Playing &&
+			oldState.resource !== newState.resource;
+
+		this._state = newState;
+
+		this.emit('stateChange', oldState, this._state);
+		if (oldState.status !== newState.status || didChangeResources) {
+			// eslint-disable-next-line @typescript-eslint/no-unsafe-argument
+			this.emit(newState.status, oldState, this._state as any);
+		}
+		this.debug?.(`state change:\nfrom ${stringifyState(oldState)}\nto ${stringifyState(newState)}`);
+	}
+
+	/**
+	 * Plays a new resource on the player. If the player is already playing a resource, the existing resource is destroyed
+	 * (it cannot be reused, even in another player) and is replaced with the new resource.
+	 *
+	 * @remarks
+	 * The player will transition to the Playing state once playback begins, and will return to the Idle state once
+	 * playback is ended.
+	 *
+	 * If the player was previously playing a resource and this method is called, the player will not transition to the
+	 * Idle state during the swap over.
+	 *
+	 * @param resource - The resource to play
+	 *
+	 * @throws Will throw if attempting to play an audio resource that has already ended, or is being played by another player
+	 */
+	public play<T>(resource: AudioResource<T>) {
+		if (resource.ended) {
+			throw new Error('Cannot play a resource that has already ended.');
+		}
+
+		if (resource.audioPlayer) {
+			if (resource.audioPlayer === this) {
+				return;
+			}
+			throw new Error('Resource is already being played by another audio player.');
+		}
+		resource.audioPlayer = this;
+
+		// Attach error listeners to the stream that will propagate the error and then return to the Idle
+		// state if the resource is still being used.
+		const onStreamError = (error: Error) => {
+			if (this.state.status !== AudioPlayerStatus.Idle) {
+				/**
+				 * Emitted when there is an error emitted from the audio resource played by the audio player
+				 *
+				 * @event AudioPlayer#error
+				 * @type {AudioPlayerError}
+				 */
+				this.emit('error', new AudioPlayerError(error, this.state.resource));
+			}
+
+			if (this.state.status !== AudioPlayerStatus.Idle && this.state.resource === resource) {
+				this.state = {
+					status: AudioPlayerStatus.Idle,
+				};
+			}
+		};
+
+		resource.playStream.once('error', onStreamError);
+
+		if (resource.started) {
+			this.state = {
+				status: AudioPlayerStatus.Playing,
+				missedFrames: 0,
+				playbackDuration: 0,
+				resource,
+				onStreamError,
+			};
+		} else {
+			const onReadableCallback = () => {
+				if (this.state.status === AudioPlayerStatus.Buffering && this.state.resource === resource) {
+					this.state = {
+						status: AudioPlayerStatus.Playing,
+						missedFrames: 0,
+						playbackDuration: 0,
+						resource,
+						onStreamError,
+					};
+				}
+			};
+
+			const onFailureCallback = () => {
+				if (this.state.status === AudioPlayerStatus.Buffering && this.state.resource === resource) {
+					this.state = {
+						status: AudioPlayerStatus.Idle,
+					};
+				}
+			};
+
+			resource.playStream.once('readable', onReadableCallback);
+
+			resource.playStream.once('end', onFailureCallback);
+			resource.playStream.once('close', onFailureCallback);
+			resource.playStream.once('finish', onFailureCallback);
+
+			this.state = {
+				status: AudioPlayerStatus.Buffering,
+				resource,
+				onReadableCallback,
+				onFailureCallback,
+				onStreamError,
+			};
+		}
+	}
+
+	/**
+	 * Pauses playback of the current resource, if any.
+	 *
+	 * @param interpolateSilence - If true, the player will play 5 packets of silence after pausing to prevent audio glitches
+	 *
+	 * @returns `true` if the player was successfully paused, otherwise `false`
+	 */
+	public pause(interpolateSilence = true) {
+		if (this.state.status !== AudioPlayerStatus.Playing) return false;
+		this.state = {
+			...this.state,
+			status: AudioPlayerStatus.Paused,
+			silencePacketsRemaining: interpolateSilence ? 5 : 0,
+		};
+		return true;
+	}
+
+	/**
+	 * Unpauses playback of the current resource, if any.
+	 *
+	 * @returns `true` if the player was successfully unpaused, otherwise `false`
+	 */
+	public unpause() {
+		if (this.state.status !== AudioPlayerStatus.Paused) return false;
+		this.state = {
+			...this.state,
+			status: AudioPlayerStatus.Playing,
+			missedFrames: 0,
+		};
+		return true;
+	}
+
+	/**
+	 * Stops playback of the current resource and destroys the resource. The player will either transition to the Idle state,
+	 * or remain in its current state until the silence padding frames of the resource have been played.
+	 *
+	 * @param force - If true, will force the player to enter the Idle state even if the resource has silence padding frames
+	 *
+	 * @returns `true` if the player will come to a stop, otherwise `false`
+	 */
+	public stop(force = false) {
+		if (this.state.status === AudioPlayerStatus.Idle) return false;
+		if (force || this.state.resource.silencePaddingFrames === 0) {
+			this.state = {
+				status: AudioPlayerStatus.Idle,
+			};
+		} else if (this.state.resource.silenceRemaining === -1) {
+			this.state.resource.silenceRemaining = this.state.resource.silencePaddingFrames;
+		}
+		return true;
+	}
+
+	/**
+	 * Checks whether the underlying resource (if any) is playable (readable)
+	 *
+	 * @returns `true` if the resource is playable, otherwise `false`
+	 */
+	public checkPlayable() {
+		const state = this._state;
+		if (state.status === AudioPlayerStatus.Idle || state.status === AudioPlayerStatus.Buffering) return false;
+
+		// If the stream has been destroyed or is no longer readable, then transition to the Idle state.
+		if (!state.resource.readable) {
+			this.state = {
+				status: AudioPlayerStatus.Idle,
+			};
+			return false;
+		}
+		return true;
+	}
+
+	/**
+	 * Called roughly every 20ms by the global audio player timer. Dispatches any audio packets that are buffered
+	 * by the active connections of this audio player.
+	 */
+	// @ts-ignore
+	private _stepDispatch() {
+		const state = this._state;
+
+		// Guard against the Idle state
+		if (state.status === AudioPlayerStatus.Idle || state.status === AudioPlayerStatus.Buffering) return;
+
+		// Dispatch any audio packets that were prepared in the previous cycle
+		this.playable.forEach((connection) => connection.dispatchAudio());
+	}
+
+	/**
+	 * Called roughly every 20ms by the global audio player timer. Attempts to read an audio packet from the
+	 * underlying resource of the stream, and then has all the active connections of the audio player prepare it
+	 * (encrypt it, append header data) so that it is ready to play at the start of the next cycle.
+	 */
+	// @ts-ignore
+	private _stepPrepare() {
+		const state = this._state;
+
+		// Guard against the Idle state
+		if (state.status === AudioPlayerStatus.Idle || state.status === AudioPlayerStatus.Buffering) return;
+
+		// List of connections that can receive the packet
+		const playable = this.playable;
+
+		/* If the player was previously in the AutoPaused state, check to see whether there are newly available
+		   connections, allowing us to transition out of the AutoPaused state back into the Playing state */
+		if (state.status === AudioPlayerStatus.AutoPaused && playable.length > 0) {
+			this.state = {
+				...state,
+				status: AudioPlayerStatus.Playing,
+				missedFrames: 0,
+			};
+		}
+
+		/* If the player is (auto)paused, check to see whether silence packets should be played and
+		   set a timeout to begin the next cycle, ending the current cycle here. */
+		if (state.status === AudioPlayerStatus.Paused || state.status === AudioPlayerStatus.AutoPaused) {
+			if (state.silencePacketsRemaining > 0) {
+				state.silencePacketsRemaining--;
+				this._preparePacket(SILENCE_FRAME, playable, state);
+				if (state.silencePacketsRemaining === 0) {
+					this._signalStopSpeaking();
+				}
+			}
+			return;
+		}
+
+		// If there are no available connections in this cycle, observe the configured "no subscriber" behavior.
+		if (playable.length === 0) {
+			if (this.behaviors.noSubscriber === NoSubscriberBehavior.Pause) {
+				this.state = {
+					...state,
+					status: AudioPlayerStatus.AutoPaused,
+					silencePacketsRemaining: 5,
+				};
+				return;
+			} else if (this.behaviors.noSubscriber === NoSubscriberBehavior.Stop) {
+				this.stop(true);
+			}
+		}
+
+		/**
+		 * Attempt to read an Opus packet from the resource. If there isn't an available packet,
+		 * play a silence packet. If there are 5 consecutive cycles with failed reads, then the
+		 * playback will end.
+		 */
+		const packet: Buffer | null = state.resource.read();
+
+		// eslint-disable-next-line @typescript-eslint/no-unnecessary-condition
+		if (state.status === AudioPlayerStatus.Playing) {
+			if (packet) {
+				this._preparePacket(packet, playable, state);
+				state.missedFrames = 0;
+			} else {
+				this._preparePacket(SILENCE_FRAME, playable, state);
+				state.missedFrames++;
+				if (state.missedFrames >= this.behaviors.maxMissedFrames) {
+					this.stop();
+				}
+			}
+		}
+	}
+
+	/**
+	 * Signals to all the subscribed connections that they should send a packet to Discord indicating
+	 * they are no longer speaking. Called once playback of a resource ends.
+	 */
+	private _signalStopSpeaking() {
+		return this.subscribers.forEach(({ connection }) => connection.setSpeaking(false));
+	}
+
+	/**
+	 * Instructs the given connections to each prepare this packet to be played at the start of the
+	 * next cycle.
+	 *
+	 * @param packet - The Opus packet to be prepared by each receiver
+	 * @param receivers - The connections that should play this packet
+	 */
+	private _preparePacket(
+		packet: Buffer,
+		receivers: VoiceConnection[],
+		state: AudioPlayerPlayingState | AudioPlayerPausedState,
+	) {
+		state.playbackDuration += 20;
+		receivers.forEach((connection) => connection.prepareAudioPacket(packet));
+	}
+}
+
+/**
+ * Stringifies an AudioPlayerState instance.
+ *
+ * @param state - The state to stringify
+ */
+function stringifyState(state: AudioPlayerState) {
+	return JSON.stringify({
+		...state,
+		resource: Reflect.has(state, 'resource'),
+		stepTimeout: Reflect.has(state, 'stepTimeout'),
+	});
+}
+
+/**
+ * Creates a new AudioPlayer to be used.
+ */
+export function createAudioPlayer(options?: CreateAudioPlayerOptions) {
+	return new AudioPlayer(options);
+}