ref/refname: Add refname validation

1 files changed, 65 insertions, 0 deletions

diff --git a/ref/refname/validate.go b/ref/refname/validate.go
new file mode 100644
index 00000000..1b8ad396
--- /dev/null
+++ b/ref/refname/validate.go
@@ -0,0 +1,65 @@
+package refname
+
+import "strings"
+
+// Validate checks whether name is one valid Git refname.
+func Validate(name string, options Options) error {
+	return validate(name, options.flags())
+}
+
+func validate(name string, flags int) error {
+	return checkOrSanitizeRefname(name, flags, nil)
+}
+
+func checkOrSanitizeRefname(name string, flags int, sanitized *strings.Builder) error {
+	componentCount := 0
+	remaining := name
+
+	if name == "@" {
+		if sanitized == nil {
+			return &NameError{Name: name, Reason: "single @ is not allowed"}
+		}
+
+		sanitized.WriteByte('-')
+	}
+
+	for {
+		if sanitized != nil && sanitized.Len() > 0 {
+			sanitized.WriteByte('/')
+		}
+
+		componentLen, err := checkRefnameComponent(remaining, &flags, sanitized, name)
+		switch {
+		case sanitized != nil && componentLen == 0:
+		case componentLen <= 0:
+			if err != nil {
+				return err
+			}
+
+			return &NameError{Name: name, Reason: "component has zero length"}
+		case err != nil:
+			return err
+		}
+
+		componentCount++
+
+		if componentLen == len(remaining) {
+			break
+		}
+
+		remaining = remaining[componentLen+1:]
+	}
+
+	componentLen := len(remaining)
+	if componentLen > 0 && remaining[componentLen-1] == '.' {
+		if sanitized == nil {
+			return &NameError{Name: name, Reason: "name ends with '.'"}
+		}
+	}
+
+	if flags&refnameAllowOneLevel == 0 && componentCount < 2 {
+		return &NameError{Name: name, Reason: "one-level refname is not allowed"}
+	}
+
+	return nil
+}