archiver: extract Readdirnames to fs package

internal/archiver/archiver.go

@@ -304,7 +304,7 @@ func (arch *Archiver) saveDir(ctx context.Context, snPath string, dir string, fi
 		return FutureNode{}, err
 	}
 
-	names, err := readdirnames(arch.FS, dir, fs.O_NOFOLLOW)
+	names, err := fs.Readdirnames(arch.FS, dir, fs.O_NOFOLLOW)
 	if err != nil {
 		return FutureNode{}, err
 	}
@@ -707,27 +707,6 @@ func (arch *Archiver) saveTree(ctx context.Context, snPath string, atree *Tree,
 	return fn, len(nodes), nil
 }
 
-// flags are passed to fs.OpenFile. O_RDONLY is implied.
-func readdirnames(filesystem fs.FS, dir string, flags int) ([]string, error) {
-	f, err := filesystem.OpenFile(dir, fs.O_RDONLY|flags, 0)
-	if err != nil {
-		return nil, errors.WithStack(err)
-	}
-
-	entries, err := f.Readdirnames(-1)
-	if err != nil {
-		_ = f.Close()
-		return nil, errors.Wrapf(err, "Readdirnames %v failed", dir)
-	}
-
-	err = f.Close()
-	if err != nil {
-		return nil, err
-	}
-
-	return entries, nil
-}
-
 // resolveRelativeTargets replaces targets that only contain relative
 // directories ("." or "../../") with the contents of the directory. Each
 // element of target is processed with fs.Clean().
@@ -743,7 +722,7 @@ func resolveRelativeTargets(filesys fs.FS, targets []string) ([]string, error) {
 		}
 
 		debug.Log("replacing %q with readdir(%q)", target, target)
-		entries, err := readdirnames(filesys, target, fs.O_NOFOLLOW)
+		entries, err := fs.Readdirnames(filesys, target, fs.O_NOFOLLOW)
 		if err != nil {
 			return nil, err
 		}

internal/archiver/scanner.go

@@ -124,7 +124,7 @@ func (s *Scanner) scan(ctx context.Context, stats ScanStats, target string) (Sca
 		stats.Files++
 		stats.Bytes += uint64(fi.Size())
 	case fi.Mode().IsDir():
-		names, err := readdirnames(s.FS, target, fs.O_NOFOLLOW)
+		names, err := fs.Readdirnames(s.FS, target, fs.O_NOFOLLOW)
 		if err != nil {
 			return stats, s.Error(target, err)
 		}

internal/archiver/tree.go

@@ -233,7 +233,7 @@ func unrollTree(f fs.FS, t *Tree) error {
 	// nodes, add the contents of Path to the nodes.
 	if t.Path != "" && len(t.Nodes) > 0 {
 		debug.Log("resolve path %v", t.Path)
-		entries, err := readdirnames(f, t.Path, 0)
+		entries, err := fs.Readdirnames(f, t.Path, 0)
 		if err != nil {
 			return err
 		}

internal/fs/file.go

@@ -1,6 +1,7 @@
 package fs
 
 import (
+	"fmt"
 	"os"
 	"path/filepath"
 	"time"
@@ -138,3 +139,24 @@ func ResetPermissions(path string) error {
 	}
 	return nil
 }
+
+// Readdirnames returns a list of file in a directory. Flags are passed to fs.OpenFile. O_RDONLY is implied.
+func Readdirnames(filesystem FS, dir string, flags int) ([]string, error) {
+	f, err := filesystem.OpenFile(dir, O_RDONLY|flags, 0)
+	if err != nil {
+		return nil, fmt.Errorf("openfile for readdirnames failed: %w", err)
+	}
+
+	entries, err := f.Readdirnames(-1)
+	if err != nil {
+		_ = f.Close()
+		return nil, fmt.Errorf("readdirnames %v failed: %w", dir, err)
+	}
+
+	err = f.Close()
+	if err != nil {
+		return nil, err
+	}
+
+	return entries, nil
+}