Merge duplicated readdir functionality

internal/archiver.readdir and internal/fs.ReadDir were unused.

internal/fs.ReadDirNames and internal/archiver.readdirnames were doing
nearly the same thing, except one sorted its output and opened with
fs.O_NOFOLLOW. Both were only used in internal/archiver.

internal/archiver/archiver.go

@@ -216,10 +216,11 @@ func (arch *Archiver) SaveDir(ctx context.Context, snPath string, fi os.FileInfo
 		return FutureTree{}, err
 	}
 
-	names, err := readdirnames(arch.FS, dir)
+	names, err := readdirnames(arch.FS, dir, fs.O_NOFOLLOW)
 	if err != nil {
 		return FutureTree{}, err
 	}
+	sort.Strings(names)
 
 	nodes := make([]FutureNode, 0, len(names))
 
@@ -628,43 +629,9 @@ func (arch *Archiver) SaveTree(ctx context.Context, snPath string, atree *Tree,
 	return tree, nil
 }
 
-type fileInfoSlice []os.FileInfo
-
-func (fi fileInfoSlice) Len() int {
-	return len(fi)
-}
-
-func (fi fileInfoSlice) Swap(i, j int) {
-	fi[i], fi[j] = fi[j], fi[i]
-}
-
-func (fi fileInfoSlice) Less(i, j int) bool {
-	return fi[i].Name() < fi[j].Name()
-}
-
-func readdir(filesystem fs.FS, dir string) ([]os.FileInfo, error) {
-	f, err := filesystem.OpenFile(dir, fs.O_RDONLY|fs.O_NOFOLLOW, 0)
-	if err != nil {
-		return nil, errors.Wrap(err, "Open")
-	}
-
-	entries, err := f.Readdir(-1)
-	if err != nil {
-		_ = f.Close()
-		return nil, errors.Wrapf(err, "Readdir %v failed", dir)
-	}
-
-	err = f.Close()
-	if err != nil {
-		return nil, err
-	}
-
-	sort.Sort(fileInfoSlice(entries))
-	return entries, nil
-}
-
-func readdirnames(filesystem fs.FS, dir string) ([]string, error) {
-	f, err := filesystem.OpenFile(dir, fs.O_RDONLY|fs.O_NOFOLLOW, 0)
+// 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.Wrap(err, "Open")
 	}
@@ -680,32 +647,32 @@ func readdirnames(filesystem fs.FS, dir string) ([]string, error) {
 		return nil, err
 	}
 
-	sort.Sort(sort.StringSlice(entries))
 	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().
-func resolveRelativeTargets(fs fs.FS, targets []string) ([]string, error) {
+func resolveRelativeTargets(filesys fs.FS, targets []string) ([]string, error) {
 	debug.Log("targets before resolving: %v", targets)
 	result := make([]string, 0, len(targets))
 	for _, target := range targets {
-		target = fs.Clean(target)
-		pc, _ := pathComponents(fs, target, false)
+		target = filesys.Clean(target)
+		pc, _ := pathComponents(filesys, target, false)
 		if len(pc) > 0 {
 			result = append(result, target)
 			continue
 		}
 
 		debug.Log("replacing %q with readdir(%q)", target, target)
-		entries, err := readdirnames(fs, target)
+		entries, err := readdirnames(filesys, target, fs.O_NOFOLLOW)
 		if err != nil {
 			return nil, err
 		}
+		sort.Strings(entries)
 
 		for _, name := range entries {
-			result = append(result, fs.Join(target, name))
+			result = append(result, filesys.Join(target, name))
 		}
 	}
 

internal/archiver/scanner.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"os"
 	"path/filepath"
+	"sort"
 
 	"github.com/restic/restic/internal/fs"
 )
@@ -86,10 +87,11 @@ 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)
+		names, err := readdirnames(s.FS, target, fs.O_NOFOLLOW)
 		if err != nil {
 			return stats, s.Error(target, fi, err)
 		}
+		sort.Strings(names)
 
 		for _, name := range names {
 			stats, err = s.scan(ctx, stats, filepath.Join(target, name))

internal/archiver/tree.go

@@ -214,7 +214,7 @@ 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 := fs.ReadDirNames(f, t.Path)
+		entries, err := readdirnames(f, t.Path, 0)
 		if err != nil {
 			return err
 		}

internal/fs/fs_helpers.go

@@ -1,45 +0,0 @@
-package fs
-
-import "os"
-
-// ReadDir reads the directory named by dirname within fs and returns a list of
-// directory entries.
-func ReadDir(fs FS, dirname string) ([]os.FileInfo, error) {
-	f, err := fs.Open(dirname)
-	if err != nil {
-		return nil, err
-	}
-
-	entries, err := f.Readdir(-1)
-	if err != nil {
-		return nil, err
-	}
-
-	err = f.Close()
-	if err != nil {
-		return nil, err
-	}
-
-	return entries, nil
-}
-
-// ReadDirNames reads the directory named by dirname within fs and returns a
-// list of entry names.
-func ReadDirNames(fs FS, dirname string) ([]string, error) {
-	f, err := fs.Open(dirname)
-	if err != nil {
-		return nil, err
-	}
-
-	entries, err := f.Readdirnames(-1)
-	if err != nil {
-		return nil, err
-	}
-
-	err = f.Close()
-	if err != nil {
-		return nil, err
-	}
-
-	return entries, nil
-}