[PATCH 1 of 4 V3 part 2] revlog: move ancestor generation out to a new class

Pierre-Yves David pierre-yves.david at logilab.fr
Tue Dec 18 10:30:19 UTC 2012


On Mon, Dec 17, 2012 at 09:30:10PM -0800, Siddharth Agarwal wrote:
> # HG changeset patch
> # User Siddharth Agarwal <sid0 at fb.com>
> # Date 1355805744 28800
> # Node ID 492535c0a3b45125888c7d20d402857cecaeae00
> # Parent  aca213182e8fffe65fecff0af0b373f4c0a3cdfc
> revlog: move ancestor generation out to a new class
> 
> This refactoring is to prepare for implementing lazy membership.
> 
> diff -r aca213182e8f -r 492535c0a3b4 mercurial/ancestor.py
> --- a/mercurial/ancestor.py	Mon Dec 17 15:08:37 2012 -0800
> +++ b/mercurial/ancestor.py	Mon Dec 17 20:42:24 2012 -0800
> @@ -5,7 +5,7 @@
>  # This software may be used and distributed according to the terms of the
>  # GNU General Public License version 2 or any later version.
>  
> -import error, heapq
> +import error, heapq, util
>  from node import nullrev
>  
>  def ancestors(pfunc, *orignodes):
> @@ -316,3 +316,53 @@
>  
>      missing.reverse()
>      return missing
> +
> +class lazyancestors(object):
> +    def __init__(self, cl, revs, stoprev=0, inclusive=False):
> +        """Create a new object generating ancestors for the given revs. Does
> +        not generate revs lower than stoprev.
> +
> +        This is computed lazily starting from revs. The object only supports
> +        iteration.
> +
> +        cl should be a changelog and revs should be an iterable. inclusive is
> +        a boolean that indicates whether revs should be included. Revs lower
> +        than stoprev will not be generated.
> +
> +        Result does not include the null revision."""
> +        self._parentrevs = cl.parentrevs
> +        self._initrevs = revs
> +        self._stoprev = stoprev
> +        self._inclusive = inclusive
> +
> +    def __iter__(self):
> +        """Generate the ancestors of _initrevs in reverse topological order.
> +
> +        If inclusive is False, yield a sequence of revision numbers starting
> +        with the parents of each revision in revs, i.e., each revision is *not*
> +        considered an ancestor of itself.  Results are in breadth-first order:
> +        parents of each rev in revs, then parents of those, etc.
> +
> +        If inclusive is True, yield all the revs first (ignoring stoprev),

I think we should honor stoprev here. That seems more sensible.

> +        then yield all the ancestors of revs as when inclusive is False.
> +        If an element in revs is an ancestor of a different rev it is not
> +        yielded again."""
> +        seen = set([nullrev])

We do not need to add nullrev here as stoprev is at least 0

> +        if self._inclusive:
> +            for rev in revs:

UnboundLocalError: local variable 'revs' referenced before assignment

Looks like you swapped those line with the ones bellow and never ran this code.

> +                yield rev
> +            seen.update(revs)
> +
> +        parentrevs = self._parentrevs
> +        revs = self._initrevs
> +        stoprev = self._stoprev
> +        visit = util.deque(revs)
> +
> +        while visit:
> +            for parent in parentrevs(visit.popleft()):
> +                if parent < stoprev:
> +                    continue
> +                if parent not in seen:
> +                    visit.append(parent)
> +                    seen.add(parent)
> +                    yield parent

what about a single branch ?

if parent >= stoprev and parent not in seen:


> diff -r aca213182e8f -r 492535c0a3b4 mercurial/revlog.py
> --- a/mercurial/revlog.py	Mon Dec 17 15:08:37 2012 -0800
> +++ b/mercurial/revlog.py	Mon Dec 17 20:42:24 2012 -0800
> @@ -345,31 +345,10 @@
>          """Generate the ancestors of 'revs' in reverse topological order.
>          Does not generate revs lower than stoprev.
>  
> -        If inclusive is False, yield a sequence of revision numbers starting
> -        with the parents of each revision in revs, i.e., each revision is *not*
> -        considered an ancestor of itself.  Results are in breadth-first order:
> -        parents of each rev in revs, then parents of those, etc.
> +        See the documentation for ancestor.lazyancestors for more details."""
>  
> -        If inclusive is True, yield all the revs first (ignoring stoprev),
> -        then yield all the ancestors of revs as when inclusive is False.
> -        If an element in revs is an ancestor of a different rev it is not
> -        yielded again.
> -
> -        Result does not include the null revision."""
> -        visit = util.deque(revs)
> -        seen = set([nullrev])
> -        if inclusive:
> -            for rev in revs:
> -                yield rev
> -            seen.update(revs)
> -        while visit:
> -            for parent in self.parentrevs(visit.popleft()):
> -                if parent < stoprev:
> -                    continue
> -                if parent not in seen:
> -                    visit.append(parent)
> -                    seen.add(parent)
> -                    yield parent
> +        return ancestor.lazyancestors(self, revs, stoprev=stoprev,
> +                                      inclusive=inclusive)
>  
>      def descendants(self, revs):
>          """Generate the descendants of 'revs' in revision order.
> _______________________________________________
> Mercurial-devel mailing list
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> http://selenic.com/mailman/listinfo/mercurial-devel

-- 
Pierre-Yves David

http://www.logilab.fr/

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