Class BundleBuilder

js/bundle/src/encoder.ts:28–241

}

export class BundleBuilder {
  private sectionLengths: Array<{ name: string; length: number }> = [];
  private sections: CBORValue[] = [];
  private responses: Uint8Array[][] = [];
  private currentResponsesOffset = 0;
  private compatAdapter: CompatAdapter;

  constructor(formatVersion: FormatVersion = DEFAULT_VERSION) {
    if (!isApprovedVersion(formatVersion)) {
      throw new Error(`Invalid webbundle format version`);
    }
    this.compatAdapter = this.createCompatAdapter(formatVersion);
  }

  createBundle(): Uint8Array {
    this.compatAdapter.onCreateBundle();

    this.addSection('index', this.fixupIndex());
    this.addSection('responses', this.responses);

    const wbn = cborg.encode(this.createTopLevel());

    // Fill in the length field.
    const view = new DataView(wbn.buffer, wbn.byteOffset + wbn.length - 8);
    view.setUint32(0, Math.floor(wbn.length / 0x100000000));
    view.setUint32(4, wbn.length & 0xffffffff);
    return wbn;
  }

  addExchange(
    url: string,
    status: number,
    headers: Headers,
    payload: Uint8Array | string
  ): BundleBuilder {
    validateExchangeURL(url);
    if (typeof payload === 'string') {
      payload = byteString(payload);
    }
    this.addIndexEntry(
      url,
      this.addResponse(new HeaderMap(status, headers), payload)
    );
    return this;
  }

  setPrimaryURL(url: string): BundleBuilder {
    return this.compatAdapter.setPrimaryURL(url);
  }

  setManifestURL(url: string): BundleBuilder {
    return this.compatAdapter.setManifestURL(url);
  }

  private addSection(name: string, content: CBORValue) {
    if (this.sectionLengths.some((s) => s.name === name)) {
      throw new Error('Duplicated section: ' + name);
    }