Function doWrite

src/gridfs/upload.ts:410–489

(
  stream: GridFSBucketWriteStream,
  chunk: Uint8Array | string,
  encoding: BufferEncoding,
  callback: Callback<void>
)

}

function doWrite(
  stream: GridFSBucketWriteStream,
  chunk: Uint8Array | string,
  encoding: BufferEncoding,
  callback: Callback<void>
): void {
  if (isAborted(stream, callback)) {
    return;
  }

  const inputBuf =
    typeof chunk === 'string' ? ByteUtils.fromUTF8(chunk) : ByteUtils.toLocalBufferType(chunk);

  stream.length += inputBuf.length;

  // Input is small enough to fit in our buffer
  if (stream.pos + inputBuf.length < stream.chunkSizeBytes) {
    ByteUtils.copy(inputBuf, stream.bufToStore, stream.pos);
    stream.pos += inputBuf.length;
    queueMicrotask(callback);
    return;
  }

  // Otherwise, buffer is too big for current chunk, so we need to flush
  // to MongoDB.
  let inputBufRemaining = inputBuf.length;
  let spaceRemaining: number = stream.chunkSizeBytes - stream.pos;
  let numToCopy = Math.min(spaceRemaining, inputBuf.length);
  let outstandingRequests = 0;
  while (inputBufRemaining > 0) {
    const inputBufPos = inputBuf.length - inputBufRemaining;
    ByteUtils.copy(inputBuf, stream.bufToStore, stream.pos, inputBufPos, inputBufPos + numToCopy);
    stream.pos += numToCopy;
    spaceRemaining -= numToCopy;
    let doc: GridFSChunk;
    if (spaceRemaining === 0) {
      doc = createChunkDoc(stream.id, stream.n, new Uint8Array(stream.bufToStore));

      const remainingTimeMS = stream.timeoutContext?.remainingTimeMS;
      if (remainingTimeMS != null && remainingTimeMS <= 0) {
        return handleError(
          stream,
          new MongoOperationTimeoutError(
            `Upload timed out after ${stream.timeoutContext?.timeoutMS}ms`
          ),
          callback
        );
      }

      ++stream.state.outstandingRequests;
      ++outstandingRequests;

      if (isAborted(stream, callback)) {
        return;
      }

      stream.chunks
        .insertOne(doc, { writeConcern: stream.writeConcern, timeoutMS: remainingTimeMS })