storage.py 文件源码

def _fix_symlinks(self):
        """Fixes symlinks in the event of an incomplete version update.

        If there is no problem with the current symlinks, this function
        has no effect.

        """
        previous_symlinks = self._previous_symlinks()
        if all(os.path.exists(link[1]) for link in previous_symlinks):
            for kind, previous_link in previous_symlinks:
                current_link = getattr(self, kind)
                if os.path.lexists(current_link):
                    os.unlink(current_link)
                os.symlink(os.readlink(previous_link), current_link)

        for _, link in previous_symlinks:
            if os.path.exists(link):
                os.unlink(link)