drop support for s3legacy layout

internal/backend/layout/layout.go

@@ -1,18 +1,7 @@
 package layout
 
 import (
-	"context"
-	"fmt"
-	"os"
-	"path/filepath"
-	"regexp"
-
 	"github.com/restic/restic/internal/backend"
-	"github.com/restic/restic/internal/debug"
-	"github.com/restic/restic/internal/errors"
-	"github.com/restic/restic/internal/feature"
-	"github.com/restic/restic/internal/fs"
-	"github.com/restic/restic/internal/restic"
 )
 
 // Layout computes paths for file name storage.
@@ -23,159 +12,3 @@ type Layout interface {
 	Paths() []string
 	Name() string
 }
-
-// Filesystem is the abstraction of a file system used for a backend.
-type Filesystem interface {
-	Join(...string) string
-	ReadDir(context.Context, string) ([]os.FileInfo, error)
-	IsNotExist(error) bool
-}
-
-// ensure statically that *LocalFilesystem implements Filesystem.
-var _ Filesystem = &LocalFilesystem{}
-
-// LocalFilesystem implements Filesystem in a local path.
-type LocalFilesystem struct {
-}
-
-// ReadDir returns all entries of a directory.
-func (l *LocalFilesystem) ReadDir(_ context.Context, dir string) ([]os.FileInfo, error) {
-	f, err := fs.Open(dir)
-	if err != nil {
-		return nil, err
-	}
-
-	entries, err := f.Readdir(-1)
-	if err != nil {
-		return nil, errors.Wrap(err, "Readdir")
-	}
-
-	err = f.Close()
-	if err != nil {
-		return nil, errors.Wrap(err, "Close")
-	}
-
-	return entries, nil
-}
-
-// Join combines several path components to one.
-func (l *LocalFilesystem) Join(paths ...string) string {
-	return filepath.Join(paths...)
-}
-
-// IsNotExist returns true for errors that are caused by not existing files.
-func (l *LocalFilesystem) IsNotExist(err error) bool {
-	return os.IsNotExist(err)
-}
-
-var backendFilenameLength = len(restic.ID{}) * 2
-var backendFilename = regexp.MustCompile(fmt.Sprintf("^[a-fA-F0-9]{%d}$", backendFilenameLength))
-
-func hasBackendFile(ctx context.Context, fs Filesystem, dir string) (bool, error) {
-	entries, err := fs.ReadDir(ctx, dir)
-	if err != nil && fs.IsNotExist(err) {
-		return false, nil
-	}
-
-	if err != nil {
-		return false, errors.Wrap(err, "ReadDir")
-	}
-
-	for _, e := range entries {
-		if backendFilename.MatchString(e.Name()) {
-			return true, nil
-		}
-	}
-
-	return false, nil
-}
-
-// ErrLayoutDetectionFailed is returned by DetectLayout() when the layout
-// cannot be detected automatically.
-var ErrLayoutDetectionFailed = errors.New("auto-detecting the filesystem layout failed")
-
-var ErrLegacyLayoutFound = errors.New("detected legacy S3 layout. Use `RESTIC_FEATURES=deprecate-s3-legacy-layout=false restic migrate s3_layout` to migrate your repository")
-
-// DetectLayout tries to find out which layout is used in a local (or sftp)
-// filesystem at the given path. If repo is nil, an instance of LocalFilesystem
-// is used.
-func DetectLayout(ctx context.Context, repo Filesystem, dir string) (Layout, error) {
-	debug.Log("detect layout at %v", dir)
-	if repo == nil {
-		repo = &LocalFilesystem{}
-	}
-
-	// key file in the "keys" dir (DefaultLayout)
-	foundKeysFile, err := hasBackendFile(ctx, repo, repo.Join(dir, defaultLayoutPaths[backend.KeyFile]))
-	if err != nil {
-		return nil, err
-	}
-
-	// key file in the "key" dir (S3LegacyLayout)
-	foundKeyFile, err := hasBackendFile(ctx, repo, repo.Join(dir, s3LayoutPaths[backend.KeyFile]))
-	if err != nil {
-		return nil, err
-	}
-
-	if foundKeysFile && !foundKeyFile {
-		debug.Log("found default layout at %v", dir)
-		return &DefaultLayout{
-			Path: dir,
-			Join: repo.Join,
-		}, nil
-	}
-
-	if foundKeyFile && !foundKeysFile {
-		if feature.Flag.Enabled(feature.DeprecateS3LegacyLayout) {
-			return nil, ErrLegacyLayoutFound
-		}
-
-		debug.Log("found s3 layout at %v", dir)
-		return &S3LegacyLayout{
-			Path: dir,
-			Join: repo.Join,
-		}, nil
-	}
-
-	debug.Log("layout detection failed")
-	return nil, ErrLayoutDetectionFailed
-}
-
-// ParseLayout parses the config string and returns a Layout. When layout is
-// the empty string, DetectLayout is used. If that fails, defaultLayout is used.
-func ParseLayout(ctx context.Context, repo Filesystem, layout, defaultLayout, path string) (l Layout, err error) {
-	debug.Log("parse layout string %q for backend at %v", layout, path)
-	switch layout {
-	case "default":
-		l = &DefaultLayout{
-			Path: path,
-			Join: repo.Join,
-		}
-	case "s3legacy":
-		if feature.Flag.Enabled(feature.DeprecateS3LegacyLayout) {
-			return nil, ErrLegacyLayoutFound
-		}
-
-		l = &S3LegacyLayout{
-			Path: path,
-			Join: repo.Join,
-		}
-	case "":
-		l, err = DetectLayout(ctx, repo, path)
-
-		// use the default layout if auto detection failed
-		if errors.Is(err, ErrLayoutDetectionFailed) && defaultLayout != "" {
-			debug.Log("error: %v, use default layout %v", err, defaultLayout)
-			return ParseLayout(ctx, repo, defaultLayout, "", path)
-		}
-
-		if err != nil {
-			return nil, err
-		}
-		debug.Log("layout detected: %v", l)
-	default:
-		return nil, errors.Errorf("unknown backend layout string %q, may be one of: default, s3legacy", layout)
-	}
-
-	return l, nil
-}