fix(dbfs): enforce root protection for single file share

pkg/filemanager/fs/dbfs/dbfs.go

@@ -448,6 +448,10 @@ func (f *DBFS) Get(ctx context.Context, path *fs.URI, opts ...fs.Option) (fs.Fil
 		return nil, fmt.Errorf("failed to get target file: %w", err)
 	}
 
+	if o.notRoot && target.IsRootFolder() {
+		return nil, fs.ErrNotSupportedAction.WithError(fmt.Errorf("cannot operate root file"))
+	}
+
 	if o.extendedInfo && target != nil {
 		extendedInfo := &fs.FileExtendedInfo{
 			StorageUsed:           target.SizeUsed(),

pkg/filemanager/fs/dbfs/options.go

@@ -25,6 +25,7 @@ type dbfsOption struct {
 	noChainedCreation          bool
 	streamListResponseCallback func(parent fs.File, file []fs.File)
 	ancestor                   *File
+	notRoot                    bool
 }
 
 func newDbfsOption() *dbfsOption {
@@ -56,6 +57,13 @@ func WithFilePublicMetadata() fs.Option {
 	})
 }
 
+// WithNotRoot force the get result cannot be a root folder
+func WithNotRoot() fs.Option {
+	return optionFunc(func(o *dbfsOption) {
+		o.notRoot = true
+	})
+}
+
 // WithContextHint enables generating context hint for the list operation.
 func WithContextHint() fs.Option {
 	return optionFunc(func(o *dbfsOption) {

pkg/filemanager/fs/dbfs/share_navigator.go

@@ -183,7 +183,7 @@ func (n *shareNavigator) To(ctx context.Context, path *fs.URI) (*File, error) {
 	elements := path.Elements()
 
 	// If target is root of single file share, the root itself is the target.
-	if len(elements) <= 1 && n.singleFileShare {
+	if len(elements) == 1 && n.singleFileShare {
 		file, err := n.latestSharedSingleFile(ctx)
 		if err != nil {
 			return nil, err

pkg/filemanager/fs/dbfs/upload.go

@@ -176,7 +176,7 @@ func (f *DBFS) PrepareUpload(ctx context.Context, req *fs.UploadRequest, opts ..
 
 func (f *DBFS) CompleteUpload(ctx context.Context, session *fs.UploadSession) (fs.File, error) {
 	// Get placeholder file
-	file, err := f.Get(ctx, session.Props.Uri, WithFileEntities())
+	file, err := f.Get(ctx, session.Props.Uri, WithFileEntities(), WithNotRoot())
 	if err != nil {
 		return nil, fmt.Errorf("failed to get placeholder file: %w", err)
 	}
@@ -270,7 +270,7 @@ func (f *DBFS) CompleteUpload(ctx context.Context, session *fs.UploadSession) (f
 		}
 	}
 
-	file, err = f.Get(ctx, session.Props.Uri, WithFileEntities())
+	file, err = f.Get(ctx, session.Props.Uri, WithFileEntities(), WithNotRoot())
 	if err != nil {
 		return nil, fmt.Errorf("failed to get updated file: %w", err)
 	}
@@ -284,7 +284,7 @@ func (f *DBFS) CompleteUpload(ctx context.Context, session *fs.UploadSession) (f
 // - File unlocked, upload session not valid
 func (f *DBFS) CancelUploadSession(ctx context.Context, path *fs.URI, sessionID string, session *fs.UploadSession) ([]fs.Entity, error) {
 	// Get placeholder file
-	file, err := f.Get(ctx, path, WithFileEntities())
+	file, err := f.Get(ctx, path, WithFileEntities(), WithNotRoot())
 	if err != nil {
 		return nil, fmt.Errorf("failed to get placeholder file: %w", err)
 	}

pkg/filemanager/fs/fs.go

@@ -158,6 +158,7 @@ type (
 		ExtendedInfo() *FileExtendedInfo
 		FolderSummary() *FolderSummary
 		Capabilities() *boolset.BooleanSet
+		IsRootFolder() bool
 	}
 
 	Entities []Entity