Mercurial > hg
view mercurial/ancestor.py @ 8496:a21605de1509
commit: move editor outside transaction
The commit editor is now invoked before files and manifest are
committed. The editor is now run with only the wlock held and aborting
an edit no longer requires rolling back a transaction. Changes to
files during a commit still result in undefined behavior.
(This is preliminary work for committing subrepositories)
author | Matt Mackall <mpm@selenic.com> |
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date | Mon, 18 May 2009 17:36:24 -0500 |
parents | 23429ebd3f9d |
children | 806e6b6cb8d8 25e572394f5c |
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# 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, incorporated herein by reference. import heapq def ancestor(a, b, pfunc): """ return the least common ancestor of nodes a and b or None if there is no such ancestor. pfunc must return a list of parent vertices """ 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