1 files changed, 59 insertions, 0 deletions
diff --git a/workhorse/internal/git/pktline.go b/workhorse/internal/git/pktline.go
new file mode 100644
index 00000000000..e970f60182d
--- /dev/null
+++ b/workhorse/internal/git/pktline.go
@@ -0,0 +1,59 @@
+package git
+
+import (
+	"bufio"
+	"bytes"
+	"fmt"
+	"io"
+	"strconv"
+)
+
+func scanDeepen(body io.Reader) bool {
+	scanner := bufio.NewScanner(body)
+	scanner.Split(pktLineSplitter)
+	for scanner.Scan() {
+		if bytes.HasPrefix(scanner.Bytes(), []byte("deepen")) && scanner.Err() == nil {
+			return true
+		}
+	}
+
+	return false
+}
+
+func pktLineSplitter(data []byte, atEOF bool) (advance int, token []byte, err error) {
+	if len(data) < 4 {
+		if atEOF && len(data) > 0 {
+			return 0, nil, fmt.Errorf("pktLineSplitter: incomplete length prefix on %q", data)
+		}
+		return 0, nil, nil // want more data
+	}
+
+	if bytes.HasPrefix(data, []byte("0000")) {
+		// special case: "0000" terminator packet: return empty token
+		return 4, data[:0], nil
+	}
+
+	// We have at least 4 bytes available so we can decode the 4-hex digit
+	// length prefix of the packet line.
+	pktLength64, err := strconv.ParseInt(string(data[:4]), 16, 0)
+	if err != nil {
+		return 0, nil, fmt.Errorf("pktLineSplitter: decode length: %v", err)
+	}
+
+	// Cast is safe because we requested an int-size number from strconv.ParseInt
+	pktLength := int(pktLength64)
+
+	if pktLength < 0 {
+		return 0, nil, fmt.Errorf("pktLineSplitter: invalid length: %d", pktLength)
+	}
+
+	if len(data) < pktLength {
+		if atEOF {
+			return 0, nil, fmt.Errorf("pktLineSplitter: less than %d bytes in input %q", pktLength, data)
+		}
+		return 0, nil, nil // want more data
+	}
+
+	// return "pkt" token without length prefix
+	return pktLength, data[4:pktLength], nil
+}