Restore file modification times

CHANGELOG.md

@@ -9,6 +9,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Added
 
+- [#212](https://github.com/meltwater/drone-cache/pull/212) `filesystem` backend now restores files modification time (with sub-second prevision if possible)
 - [#209](https://github.com/meltwater/drone-cache/pull/209) Added double star directory searching in mounts (e.g. `path/**/subdir`)
 - [#198](https://github.com/meltwater/drone-cache/pull/198) Add `hashFiles` template function to generate the SHA256 hash of multiple files
 

archive/tar/tar.go

@@ -72,6 +72,7 @@ func writeToArchive(tw *tar.Writer, root string, skipSymlinks bool, written *int
 		if err != nil {
 			return fmt.Errorf("create header for <%s>, %w", path, err)
 		}
+		h.Format = tar.FormatPAX
 
 		if fi.Mode()&os.ModeSymlink != 0 { // isSymbolic
 			if skipSymlinks {
@@ -254,6 +255,12 @@ func extractRegular(h *tar.Header, tr io.Reader, target string) (int64, error) {
 		return written, fmt.Errorf("copy extracted file for writing <%s>, %w", target, err)
 	}
 
+	if !h.ModTime.IsZero() {
+		if err = os.Chtimes(target, h.AccessTime, h.ModTime); err != nil {
+			return written, fmt.Errorf("set atime/mtime <%s>, %w", target, err)
+		}
+	}
+
 	return written, nil
 }