69         self._revlog = repo.changelog

    69         self._revlog = repo.changelog

    70 

    70 

    71     def __nonzero__(self):

    71     def __nonzero__(self):

    72         """return True if any revision to navigate over"""

    72         """return True if any revision to navigate over"""

    73         return self._first() is not None

    73         return self._first() is not None

    74 

    76 

    75     def _first(self):

    77     def _first(self):

    76         """return the minimum non-filtered changeset or None"""

    78         """return the minimum non-filtered changeset or None"""

    77         try:

    79         try:

    78             return next(iter(self._revlog))

    80             return next(iter(self._revlog))