1 files changed, 40 insertions, 0 deletions
diff --git a/logutil/logutil.go b/logutil/logutil.go
new file mode 100644
index 0000000..467e57d
--- /dev/null
+++ b/logutil/logutil.go
@@ -0,0 +1,40 @@
+package logutil
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+)
+
+const (
+	cursorUp = "\033[1A"
+	eraseEOL = "\033[K"
+)
+
+type UniqueWriter struct {
+	w     io.Writer
+	prev  []byte
+	count int64
+}
+
+func NewUniqueWriter(w io.Writer) *UniqueWriter { return &UniqueWriter{w: w} }
+
+func (uw *UniqueWriter) Write(p []byte) (n int, err error) {
+	if len(p) == 0 {
+		return 0, nil
+	}
+	if bytes.Equal(uw.prev, p) {
+		uw.count++
+		if p[len(p)-1] == '\n' {
+			p = p[:len(p)-1]
+		}
+		space := ""
+		if len(p) > 0 {
+			space = " "
+		}
+		return fmt.Fprintf(uw.w, "%s%s%s%s[repeated %d times]\n", cursorUp, eraseEOL, p, space, uw.count)
+	}
+	uw.prev = p
+	uw.count = 1
+	return uw.w.Write(p)
+}