Add ReferenceNormalizeName (#681)

Author: Segev Finer

reference.go

@@ -488,3 +488,42 @@ func ReferenceIsValidName(name string) bool {
 	}
 	return false
 }
+
+const (
+	// This should match GIT_REFNAME_MAX in src/refs.h
+	_refnameMaxLength = C.size_t(1024)
+)
+
+type ReferenceFormat uint
+
+const (
+	ReferenceFormatNormal           ReferenceFormat = C.GIT_REFERENCE_FORMAT_NORMAL
+	ReferenceFormatAllowOnelevel    ReferenceFormat = C.GIT_REFERENCE_FORMAT_ALLOW_ONELEVEL
+	ReferenceFormatRefspecPattern   ReferenceFormat = C.GIT_REFERENCE_FORMAT_REFSPEC_PATTERN
+	ReferenceFormatRefspecShorthand ReferenceFormat = C.GIT_REFERENCE_FORMAT_REFSPEC_SHORTHAND
+)
+
+// ReferenceNormalizeName normalizes the reference name and checks validity.
+//
+// This will normalize the reference name by removing any leading slash '/'
+// characters and collapsing runs of adjacent slashes between name components
+// into a single slash.
+//
+// See git_reference_symbolic_create() for rules about valid names.
+func ReferenceNormalizeName(name string, flags ReferenceFormat) (string, error) {
+	cname := C.CString(name)
+	defer C.free(unsafe.Pointer(cname))
+
+	buf := (*C.char)(C.malloc(_refnameMaxLength))
+	defer C.free(unsafe.Pointer(buf))
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ecode := C.git_reference_normalize_name(buf, _refnameMaxLength, cname, C.uint(flags))
+	if ecode < 0 {
+		return "", MakeGitError(ecode)
+	}
+
+	return C.GoString(buf), nil
+}

reference_test.go

@@ -224,6 +224,29 @@ func TestReferenceIsValidName(t *testing.T) {
 	}
 }
 
+func TestReferenceNormalizeName(t *testing.T) {
+	t.Parallel()
+
+	ref, err := ReferenceNormalizeName("refs/heads//master", ReferenceFormatNormal)
+	checkFatal(t, err)
+
+	if ref != "refs/heads/master" {
+		t.Errorf("ReferenceNormalizeName(%q) = %q; want %q", "refs/heads//master", ref, "refs/heads/master")
+	}
+
+	ref, err = ReferenceNormalizeName("master", ReferenceFormatAllowOnelevel|ReferenceFormatRefspecShorthand)
+	checkFatal(t, err)
+
+	if ref != "master" {
+		t.Errorf("ReferenceNormalizeName(%q) = %q; want %q", "master", ref, "master")
+	}
+
+	ref, err = ReferenceNormalizeName("foo^", ReferenceFormatNormal)
+	if !IsErrorCode(err, ErrInvalidSpec) {
+		t.Errorf("foo^ should be invalid")
+	}
+}
+
 func compareStringList(t *testing.T, expected, actual []string) {
 	for i, v := range expected {
 		if actual[i] != v {