rx-player/src/manifest/classes/codec_support_cache.ts

Canal+ HTML5 Video Player

/**
 * Interface representing codec and support information.
 */
export interface ICodecSupportInfo extends ICodecSupportMatrix {
  mimeType: string;
  codec: string;
}
/**
 * Interface representing support information.
 */
interface ICodecSupportMatrix {
  supported?: boolean | undefined;
  supportedIfEncrypted?: boolean | undefined;
}
/**
 * Class setting up a cache of which codec is currently known to be supported or
 * not.
 *
 * We keep this only at the Manifest level because external conditions can change
 * from Manifest to Manifest (e.g. not the same decryption cabalities used etc.).
 */
export default class CodecSupportCache {
  public supportMap: Map<string, Map<string, ICodecSupportMatrix>>;

  /**
   * Constructs an CodecSupportCache instance.
   * @param {Array} codecList - List of codec support information.
   */
  constructor(codecList: ICodecSupportInfo[]) {
    this.supportMap = new Map();
    this.addCodecs(codecList);
  }

  /**
   * Adds codec support information to this `CodecSupportCache`.
   * @param {Array} codecList - List of codec support information.
   */
  public addCodecs(codecList: ICodecSupportInfo[]) {
    for (const codec of codecList) {
      let mimeTypeMap = this.supportMap.get(codec.mimeType);
      if (mimeTypeMap === undefined) {
        mimeTypeMap = new Map();
        this.supportMap.set(codec.mimeType, mimeTypeMap);
      }

      mimeTypeMap.set(codec.codec, {
        supported: codec.supported,
        supportedIfEncrypted: codec.supportedIfEncrypted,
      });
    }
  }

  /**
   * Checks if a codec is supported for a given MIME type.
   * @param {string} mimeType - The MIME type to check.
   * @param {string} codec - The codec to check.
   * @param {boolean} isEncrypted - Whether the content is encrypted.
   * @returns {boolean | undefined} - `true` if the codec is supported, `false`
   * if not, or `undefined` if no support information is found.
   */
  public isSupported(
    mimeType: string,
    codec: string,
    isEncrypted: boolean,
  ): boolean | undefined {
    const mimeTypeMap = this.supportMap.get(mimeType);
    if (mimeTypeMap === undefined) {
      return undefined;
    }

    const result = mimeTypeMap.get(codec);
    if (result === undefined) {
      return undefined;
    }

    if (isEncrypted) {
      return result.supportedIfEncrypted;
    } else {
      return result.supported;
    }
  }
}