syncthing/lib/versioner/util.go

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// Copyright (C) 2014 The Syncthing Authors.
//
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// 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 https://mozilla.org/MPL/2.0/.
package versioner
import (
"path/filepath"
"regexp"
"strings"
)
// Inserts ~tag just before the extension of the filename.
func TagFilename(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)
}
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var tagExp = regexp.MustCompile(`.*~([^~.]+)(?:\.[^.]+)?$`)
// Returns the tag from a filename, whether at the end or middle.
func ExtractTag(path string) string {
match := tagExp.FindStringSubmatch(path)
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// match is []string{"whole match", "submatch"} when successful
if len(match) != 2 {
return ""
}
return match[1]
}
func UntagFilename(path string) (string, string) {
ext := filepath.Ext(path)
versionTag := ExtractTag(path)
// Files tagged with old style tags cannot be untagged.
if versionTag == "" || strings.HasSuffix(ext, versionTag) {
return "", ""
}
withoutExt := path[:len(path)-len(ext)-len(versionTag)-1]
name := withoutExt + ext
return name, versionTag
}