func fillWorkerBuffer()

in sharedlibraries/storage/parallelreader.go [160:188]

• 25 lines of code
• 8 McCabe index (conditional complexity)

func fillWorkerBuffer(r *ParallelReader, worker *downloadWorker, startByte int64) error {
	// Assigns reader to worker with the given startByte and chunk length.
	var err error
	if worker.reader, err = worker.object.NewRangeReader(r.ctx, startByte, r.partSizeBytes); err != nil {
		return fmt.Errorf("failed to create range reader: %v", err)
	}

	// Reads data into the worker's buffer until the whole length is read.
	bytesRead := int64(0)
	for {
		select {
		case <-r.ctx.Done():
			return fmt.Errorf("context cancellation called")
		default:
			var n int
			if n, err = worker.reader.Read(worker.buffer[bytesRead:]); err != nil && err != io.EOF {
				return fmt.Errorf("failed to read from range reader: %v", err)
			}
			if n == 0 || err == io.EOF {
				// When all bytes are read, the loop will exit.
				worker.BytesRemain = bytesRead
				worker.chunkSize = bytesRead
				worker.bufferOffset = 0
				return nil
			}
			bytesRead += int64(n)
		}
	}
}