expo/src/AV.js

The Expo SDK

// @flow

import Asset from './Asset';

// TODO add:
//  disableFocusOnAndroid
//  audio routes (at least did become noisy on android)
//  pan
//  pitch
//  API to explicitly request audio focus / session
//  API to select stream type on Android
//  subtitles API

export type PlaybackSource = number | { uri: string } | Asset;

export type PlaybackStatus =
  | {
      isLoaded: false,
      error?: string, // populated exactly once when an error forces the object to unload
    }
  | {
      isLoaded: true,

      uri: string,

      progressUpdateIntervalMillis: number,
      durationMillis: number,
      positionMillis: number,
      playableDurationMillis: number,

      shouldPlay: boolean,
      isPlaying: boolean,
      isBuffering: boolean,

      rate: number,
      shouldCorrectPitch: boolean,
      volume: number,
      isMuted: boolean,
      isLooping: boolean,

      didJustFinish: boolean, // true exactly once when the track plays to finish
    };

export type PlaybackStatusToSet = {
  progressUpdateIntervalMillis?: number,
  positionMillis?: number,
  shouldPlay?: boolean,
  rate?: number,
  shouldCorrectPitch?: boolean,
  volume?: number,
  isMuted?: boolean,
  isLooping?: boolean,
};

export const _DEFAULT_PROGRESS_UPDATE_INTERVAL_MILLIS: number = 500;
export const _DEFAULT_INITIAL_PLAYBACK_STATUS: PlaybackStatusToSet = {
  positionMillis: 0,
  progressUpdateIntervalMillis: _DEFAULT_PROGRESS_UPDATE_INTERVAL_MILLIS,
  shouldPlay: false,
  rate: 1.0,
  shouldCorrectPitch: false,
  volume: 1.0,
  isMuted: false,
  isLooping: false,
};

const _getAssetFromPlaybackSource = (source: ?PlaybackSource): ?Asset => {
  if (source == null) {
    return null;
  }

  let asset: ?Asset = null;
  if (typeof source === 'number') {
    asset = Asset.fromModule(source);
  } else if ('constructor' in source && source.constructor.name === 'Asset') {
    asset = source;
  }
  return asset;
};

export const _getURIFromSource = (source: ?PlaybackSource): ?string => {
  let uri: ?string = null;
  let asset: ?Asset = _getAssetFromPlaybackSource(source);
  if (asset != null) {
    uri = asset.localUri || asset.uri;
  } else if (
    source != null &&
    typeof source !== 'number' &&
    'uri' in source &&
    typeof source.uri === 'string'
  ) {
    uri = source.uri;
  }
  return uri;
};

export const _throwErrorIfValuesOutOfBoundsInStatus = async (
  status: PlaybackStatusToSet
) => {
  if ('rate' in status && (status.rate < 0.0 || status.rate > 32.0)) {
    throw new Error('Rate value must be between 0.0 and 32.0.');
  }
  if ('volume' in status && (status.volume < 0.0 || status.volume > 1.0)) {
    throw new Error('Volume value must be between 0.0 and 1.0.');
  }
};

export const _getURIAndFullInitialStatusForLoadAsync = async (
  source: ?PlaybackSource,
  initialStatus: ?PlaybackStatusToSet,
  downloadFirst: boolean
): Promise<{ uri: string, fullInitialStatus: PlaybackStatusToSet }> => {
  // Download first if necessary.
  let asset: ?Asset = _getAssetFromPlaybackSource(source);
  if (downloadFirst && asset != null) {
    // TODO we can download remote uri too once @nikki93 has integrated this into Asset
    await asset.downloadAsync();
  }

  // Get the URI
  const uri: ?string = _getURIFromSource(source);
  if (uri == null) {
    throw new Error('Cannot load null source!');
  }

  // Get the full initial status
  const fullInitialStatus: PlaybackStatusToSet = initialStatus == null
    ? _DEFAULT_INITIAL_PLAYBACK_STATUS
    : {
        ..._DEFAULT_INITIAL_PLAYBACK_STATUS,
        ...initialStatus,
      };
  _throwErrorIfValuesOutOfBoundsInStatus(fullInitialStatus);

  return { uri, fullInitialStatus };
};

export const _getUnloadedStatus = (error: ?string = null): PlaybackStatus => {
  const status: PlaybackStatus = { isLoaded: false };
  if (error) {
    status.error = error;
  }
  return status;
};

// TODO Unify 8 native calls into 4 by folding out PlayerData and then setting it in the Video component.
export const _COMMON_AV_PLAYBACK_METHODS = {
  // The following are separately defined in each playback object:
  //   getStatusAsync
  //   setCallback
  //   loadAsync
  //   unloadAsync
  //   setStatusAsync

  async playAsync(): Promise<PlaybackStatus> {
    return this.setStatusAsync({ shouldPlay: true });
  },
  async playFromPositionAsync(positionMillis: number): Promise<PlaybackStatus> {
    return this.setStatusAsync({ positionMillis, shouldPlay: true });
  },
  async pauseAsync(): Promise<PlaybackStatus> {
    return this.setStatusAsync({ shouldPlay: false });
  },
  async stopAsync(): Promise<PlaybackStatus> {
    return this.setStatusAsync({ positionMillis: 0, shouldPlay: false });
  },
  async setPositionAsync(positionMillis: number): Promise<PlaybackStatus> {
    return this.setStatusAsync({ positionMillis });
  },
  async setRateAsync(
    rate: number,
    shouldCorrectPitch: boolean
  ): Promise<PlaybackStatus> {
    return this.setStatusAsync({ rate, shouldCorrectPitch });
  },
  async setVolumeAsync(volume: number): Promise<PlaybackStatus> {
    return this.setStatusAsync({ volume });
  },
  async setIsMutedAsync(isMuted: boolean): Promise<PlaybackStatus> {
    return this.setStatusAsync({ isMuted });
  },
  async setIsLoopingAsync(isLooping: boolean): Promise<PlaybackStatus> {
    return this.setStatusAsync({ isLooping });
  },
  async setProgressUpdateIntervalAsync(
    progressUpdateIntervalMillis: number
  ): Promise<PlaybackStatus> {
    return this.setStatusAsync({ progressUpdateIntervalMillis });
  },
};