comparison mercurial/revset.py @ 26306:d157e1f18e3f

revset: speed up existence checks for ordered filtered sets

Previously, calling 'if foo:' on a ordered filtered set would start iterating in
whatever the current direction was and return if a value was available. If the
current direction was ascending, but the set had a fastdesc available, this
meant we did a lot more work than necessary.

If this was applied without my previous max/min fixes, it would improve max()
performance (this was my first attempt at fixing the issue). Since those
previous fixes went in though, this doesn't have a visible benefit in the
benchmarks, but it does seem clearly better than it was before so I think it
should still go in.

26305:ade5c488d622

        if it is None:
            return None
        return lambda: self._iterfilter(it())

    def __nonzero__(self):
        for r in self:
            return True
        return False

    def __len__(self):
        # Basic implementation to be changed in future patches.

26306:d157e1f18e3f

        if it is None:
            return None
        return lambda: self._iterfilter(it())

    def __nonzero__(self):
        it = self
        fast = self.fastasc or self.fastdesc
        if fast:
            it = fast()

        for r in it:
            return True
        return False

    def __len__(self):
        # Basic implementation to be changed in future patches.