func()

in go/pkg/fakes/cas.go [61:122]

• 57 lines of code
• 21 McCabe index (conditional complexity)

func (f *Reader) Read(req *bspb.ReadRequest, stream bsgrpc.ByteStream_ReadServer) error {
	path := strings.Split(req.ResourceName, "/")
	if (len(path) != 4 && len(path) != 5) || path[0] != "instance" || (path[1] != "blobs" && path[1] != "compressed-blobs") {
		return status.Error(codes.InvalidArgument, "test fake expected resource name of the form \"instance/blobs|compressed-blobs/<compressor?>/<hash>/<size>\"")
	}
	// indexOffset for all 2+ paths - `compressed-blobs` has one more URI element.
	indexOffset := 0
	if path[1] == "compressed-blobs" {
		indexOffset = 1
	}

	dg := digest.NewFromBlob(f.Blob)
	if path[2+indexOffset] != dg.Hash || path[3+indexOffset] != strconv.FormatInt(dg.Size, 10) {
		return status.Errorf(codes.NotFound, "test fake only has blob with digest %s, but %s/%s was requested", dg, path[2+indexOffset], path[3+indexOffset])
	}

	offset := req.ReadOffset
	limit := req.ReadLimit
	blob := f.Blob
	chunks := f.Chunks
	if path[1] == "compressed-blobs" {
		if !f.ExpectCompressed {
			return status.Errorf(codes.FailedPrecondition, "fake expected a call with uncompressed bytes")
		}
		if path[2] != "zstd" {
			return status.Error(codes.InvalidArgument, "test fake expected valid compressor, eg zstd")
		}
		blob = zstdEncoder.EncodeAll(blob[offset:], nil)
		offset = 0
		// For simplicity in coordinating test server & client, compressed blobs are returned as
		// one chunk.
		chunks = []int{len(blob)}
	} else if f.ExpectCompressed {
		return status.Errorf(codes.FailedPrecondition, "fake expected a call with compressed bytes")
	}
	for len(chunks) > 0 {
		buf := blob[:chunks[0]]
		if offset >= int64(len(buf)) {
			offset -= int64(len(buf))
		} else {
			if offset > 0 {
				buf = buf[offset:]
				offset = 0
			}
			if limit > 0 {
				if limit < int64(len(buf)) {
					buf = buf[:limit]
				}
				limit -= int64(len(buf))
			}
			if err := stream.Send(&bspb.ReadResponse{Data: buf}); err != nil {
				return err
			}
			if limit == 0 && req.ReadLimit != 0 {
				break
			}
		}
		blob = blob[chunks[0]:]
		chunks = chunks[1:]
	}
	return nil
}