Mercurial > hg
view mercurial/ancestor.py @ 10404:3e7cbe859871
revlog.size: remove alternate implementation (revlogv0 specific)
it's only useful for revlogv0 anyway, revlogNG has the uncompressed size in
the index.
author | Benoit Boissinot <benoit.boissinot@ens-lyon.org> |
---|---|
date | Tue, 09 Feb 2010 14:02:07 +0100 |
parents | d6512b3e9ac0 |
children | 67bb9d78f05e |
line wrap: on
line source
# ancestor.py - generic DAG ancestor algorithm for mercurial # # Copyright 2006 Matt Mackall <mpm@selenic.com> # # This software may be used and distributed according to the terms of the # GNU General Public License version 2 or any later version. import heapq def ancestor(a, b, pfunc): """ return a minimal-distance ancestor of nodes a and b, or None if there is no such ancestor. Note that there can be several ancestors with the same (minimal) distance, and the one returned is arbitrary. pfunc must return a list of parent vertices for a given vertex """ if a == b: return a # find depth from root of all ancestors parentcache = {} visit = [a, b] depth = {} while visit: vertex = visit[-1] pl = pfunc(vertex) parentcache[vertex] = pl if not pl: depth[vertex] = 0 visit.pop() else: for p in pl: if p == a or p == b: # did we find a or b as a parent? return p # we're done if p not in depth: visit.append(p) if visit[-1] == vertex: depth[vertex] = min([depth[p] for p in pl]) - 1 visit.pop() # traverse ancestors in order of decreasing distance from root def ancestors(vertex): h = [(depth[vertex], vertex)] seen = set() while h: d, n = heapq.heappop(h) if n not in seen: seen.add(n) yield (d, n) for p in parentcache[n]: heapq.heappush(h, (depth[p], p)) def generations(vertex): sg, s = None, set() for g, v in ancestors(vertex): if g != sg: if sg: yield sg, s sg, s = g, set((v,)) else: s.add(v) yield sg, s x = generations(a) y = generations(b) gx = x.next() gy = y.next() # increment each ancestor list until it is closer to root than # the other, or they match try: while 1: if gx[0] == gy[0]: for v in gx[1]: if v in gy[1]: return v gy = y.next() gx = x.next() elif gx[0] > gy[0]: gy = y.next() else: gx = x.next() except StopIteration: return None