ref/refname: Add refname validation

1 files changed, 22 insertions, 0 deletions

diff --git a/ref/refname/utils.go b/ref/refname/utils.go
new file mode 100644
index 00000000..58944748
--- /dev/null
+++ b/ref/refname/utils.go
@@ -0,0 +1,22 @@
+package refname
+
+import (
+	"strings"
+)
+
+func overwriteLastByte(builder *strings.Builder, ch byte) {
+	overwriteBuilderAt(builder, builder.Len()-1, ch)
+}
+
+func overwriteBuilderAt(builder *strings.Builder, index int, ch byte) {
+	value := builder.String()
+	truncateBuilder(builder, index)
+	builder.WriteByte(ch)
+	builder.WriteString(value[index+1:])
+}
+
+func truncateBuilder(builder *strings.Builder, n int) {
+	value := builder.String()
+	builder.Reset()
+	builder.WriteString(value[:n])
+}