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// Package version provides machinery for versioning file names
// with a timestamp-based version string
package version
import (
"path"
"regexp"
"strings"
"time"
)
const versionFormat = "-v2006-01-02-150405.000"
var versionRegexp = regexp.MustCompile(`-v\d{4}-\d{2}-\d{2}-\d{6}-\d{3}`)
// Split fileName into base and extension so that base + ext == fileName
func splitExt(fileName string) (base, ext string) {
ext = path.Ext(fileName)
base = fileName[:len(fileName)-len(ext)]
// .file splits to base == "", ext == ".file"
// so swap ext and base in this case
if ext != "" && base == "" {
base, ext = ext, base
}
return base, ext
}
// Add returns fileName modified to include t as the version
func Add(fileName string, t time.Time) string {
base, ext := splitExt(fileName)
s := t.Format(versionFormat)
// Replace the '.' with a '-'
s = strings.ReplaceAll(s, ".", "-")
return base + s + ext
}
// Remove returns a modified fileName without the version string and the time it represented
// If the fileName did not have a version then time.Time{} is returned along with an unmodified fileName
func Remove(fileName string) (t time.Time, fileNameWithoutVersion string) {
fileNameWithoutVersion = fileName
base, ext := splitExt(fileName)
if len(base) < len(versionFormat) {
return
}
versionStart := len(base) - len(versionFormat)
// Check it ends in -xxx
if base[len(base)-4] != '-' {
return
}
// Replace with .xxx for parsing
base = base[:len(base)-4] + "." + base[len(base)-3:]
newT, err := time.Parse(versionFormat, base[versionStart:])
if err != nil {
return
}
return newT, base[:versionStart] + ext
}
// Match returns true if the fileName has a version string
func Match(fileName string) bool {
return versionRegexp.MatchString(fileName)
}
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