Method read

src/utils.ts:840–873

Reads the requested number of bytes, optionally consuming them

(size: number)

  /** Reads the requested number of bytes, optionally consuming them */
  read(size: number): Uint8Array {
    if (typeof size !== 'number' || size < 0) {
      throw new MongoInvalidArgumentError('Argument "size" must be a non-negative number');
    }

    // oversized request returns empty buffer
    if (size > this.totalByteLength) {
      return ByteUtils.allocate(0);
    }

    // We know we have enough, we just don't know how it is spread across chunks
    // TODO(NODE-4732): alloc API should change based on raw option
    const result = ByteUtils.allocateUnsafe(size);

    for (let bytesRead = 0; bytesRead < size; ) {
      const buffer = this.buffers.shift();
      if (buffer == null) {
        break;
      }
      const bytesRemaining = size - bytesRead;
      const bytesReadable = Math.min(bytesRemaining, buffer.byteLength);
      const bytes = buffer.subarray(0, bytesReadable);

      result.set(bytes, bytesRead);

      bytesRead += bytesReadable;
      this.totalByteLength -= bytesReadable;
      if (bytesReadable < buffer.byteLength) {
        this.buffers.unshift(buffer.subarray(bytesReadable));
      }
    }

    return result;
  }
}

/** @public */