async flush()

in src/recordlayer.js [195:236]
35 lines of code
6 McCabe index (conditional complexity)

  async flush() {
    // If there's nothing to flush, bail out early.
    // Don't throw `_sendError` if we're not sending anything, because `flush()`
    // can be called when we're trying to transition into an error state.
    const buf = this._pendingRecordBuf;
    let type = this._pendingRecordType;
    if (! type) {
      if (buf !== null) {
        throw new TLSError(ALERT_DESCRIPTION.INTERNAL_ERROR);
      }
      return;
    }
    if (this._sendError !== null) {
      throw this._sendError;
    }
    // If we're encrypting, turn the existing buffer contents into a `TLSInnerPlaintext` by
    // appending the type. We don't do any zero-padding, although the spec allows it.
    let inflation = 0, innerPlaintext = null;
    if (this._sendEncryptState !== null) {
      buf.writeUint8(type);
      innerPlaintext = buf.slice(RECORD_HEADER_SIZE);
      inflation = AEAD_SIZE_INFLATION;
      type = RECORD_TYPE.APPLICATION_DATA;
    }
    // Write the common header for either `TLSPlaintext` or `TLSCiphertext` record.
    const length = buf.tell() - RECORD_HEADER_SIZE + inflation;
    buf.seek(0);
    buf.writeUint8(type);
    buf.writeUint16(VERSION_TLS_1_2);
    buf.writeUint16(length);
    // Followed by different payload depending on encryption status.
    if (this._sendEncryptState !== null) {
      const additionalData = buf.slice(0, RECORD_HEADER_SIZE);
      const ciphertext = await this._sendEncryptState.encrypt(innerPlaintext, additionalData);
      buf.writeBytes(ciphertext);
    } else {
      buf.incr(length);
    }
    this._pendingRecordBuf = null;
    this._pendingRecordType = 0;
    await this.sendCallback(buf.flush());
  }