mv internal lib

lib/versioner/util.go

@@ -0,0 +1,48 @@
+// Copyright (C) 2014 The Syncthing Authors.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at http://mozilla.org/MPL/2.0/.
+
+package versioner
+
+import (
+	"path/filepath"
+	"regexp"
+	"sort"
+)
+
+// Inserts ~tag just before the extension of the filename.
+func taggedFilename(name, tag string) string {
+	dir, file := filepath.Dir(name), filepath.Base(name)
+	ext := filepath.Ext(file)
+	withoutExt := file[:len(file)-len(ext)]
+	return filepath.Join(dir, withoutExt+"~"+tag+ext)
+}
+
+var tagExp = regexp.MustCompile(`.*~([^~.]+)(?:\.[^.]+)?$`)
+
+// Returns the tag from a filename, whether at the end or middle.
+func filenameTag(path string) string {
+	match := tagExp.FindStringSubmatch(path)
+	// match is []string{"whole match", "submatch"} when successful
+
+	if len(match) != 2 {
+		return ""
+	}
+	return match[1]
+}
+
+func uniqueSortedStrings(strings []string) []string {
+	seen := make(map[string]struct{}, len(strings))
+	unique := make([]string, 0, len(strings))
+	for _, str := range strings {
+		_, ok := seen[str]
+		if !ok {
+			seen[str] = struct{}{}
+			unique = append(unique, str)
+		}
+	}
+	sort.Strings(unique)
+	return unique
+}