ostree/ostree_dest.go
func newImageDestination(ref ostreeReference, tmpDirPath string) (types.ImageDestination, error) {
	tmpDirPath = filepath.Join(tmpDirPath, ref.branchName)
	if err := ensureDirectoryExists(tmpDirPath); err != nil {
		return nil, err
	}
	return &ostreeImageDestination{ref, "", manifestSchema{}, tmpDirPath, map[string]*blobToImport{}, "", 0, nil}, nil
}
func newImageDestination(ref ostreeReference, tmpDirPath string) (types.ImageDestination, error) {
	tmpDirPath = filepath.Join(tmpDirPath, ref.branchName)
	if err := ensureDirectoryExists(tmpDirPath); err != nil {
		return nil, err
	}
	return &ostreeImageDestination{ref, "", manifestSchema{}, tmpDirPath, map[string]*blobToImport{}, "", 0, nil}, nil
}
// newImageDestination returns an ImageDestination for writing to an existing ostree.