Mercurial > hg
changeset 3135:b1db258e875c
Abstract ancestor algorithm into generic function
Make depth calculation non-recursive
Add simple shortcut for linear ancestry
Convert context to use ancestor function
make memoized parents function
Convert revlog to use ancestor function
| author | Matt Mackall <mpm@selenic.com> |
|---|---|
| date | Wed, 20 Sep 2006 16:50:50 -0500 |
| parents | abd9a05fca0b |
| children | 2c472ab42b08 |
| files | mercurial/ancestor.py mercurial/context.py mercurial/revlog.py |
| diffstat | 3 files changed, 107 insertions(+), 169 deletions(-) [+] |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/mercurial/ancestor.py Wed Sep 20 16:50:50 2006 -0500 @@ -0,0 +1,83 @@ +# 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, 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 + visit = [a, b] + depth = {} + while visit: + vertex = visit[-1] + pl = pfunc(vertex) + 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 = {} + while h: + d, n = heapq.heappop(h) + if n not in seen: + seen[n] = 1 + yield (d, n) + for p in pfunc(n): + heapq.heappush(h, (depth[p], p)) + + def generations(vertex): + sg, s = None, {} + for g,v in ancestors(vertex): + if g != sg: + if sg: + yield sg, s + sg, s = g, {v:1} + else: + s[v] = 1 + 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
--- a/mercurial/context.py Tue Sep 19 15:28:13 2006 -0500 +++ b/mercurial/context.py Wed Sep 20 16:50:50 2006 -0500 @@ -7,7 +7,7 @@ from node import * from demandload import demandload -demandload(globals(), "heapq") +demandload(globals(), "ancestor") class changectx(object): """A changecontext object makes access to data related to a particular @@ -161,103 +161,26 @@ find the common ancestor file context, if any, of self, and fc2 """ - a, b = (self._path, self._filenode), (fc2._path, fc2._filenode) - - if a == b: - return self - - if a[0] == b[0]: - n = self._filelog.ancestor(a[1], b[1]) - if n != nullid: - return filectx(self._repo, self._path, - fileid=n, filelog=self._filelog) - - # build a graph of all ancestors, crossing renames - ag = {} - fv = [a, b] + acache = {} flcache = {self._path:self._filelog, fc2._path:fc2._filelog} - - while fv: - f,n = fv.pop() - try: - fl = flcache[f] - except KeyError: + def parents(vertex): + if vertex in acache: + return acache[vertex] + f, n = vertex + if f not in flcache: flcache[f] = self._repo.file(f) - fl = flcache[f] - v = [n] - while v: - n = v.pop() - c = (f, n) - if c in ag: - continue - - pl = [ n for n in fl.parents(n) if n != nullid ] - v += pl - pl = [ (f, n) for n in pl ] - re = fl.renamed(n) - if re: - pl.append(re) - if re not in ag: - fv.append(re) - ag[c] = pl + fl = flcache[f] + pl = [ (f,p) for p in fl.parents(n) if p != nullid ] + re = fl.renamed(n) + if re: + pl.append(re) + acache[vertex]=pl + return pl - dist = {} - def depth(node): - try: - return dist[node] - except KeyError: - pl = ag[node] - if not pl: - dist[node] = 0 - else: - dist[node] = max([depth(p) for p in pl]) + 1 - return dist[node] - - # traverse ancestors in order of decreasing distance from root - def ancestors(vertex): - h = [(-depth(vertex), vertex)] - seen = {} - while h: - d, v = heapq.heappop(h) - if v not in seen: - seen[v] = 1 - yield (-d, v) - for p in ag[v]: - heapq.heappush(h, (-depth(p), p)) + a, b = (self._path, self._filenode), (fc2._path, fc2._filenode) + v = ancestor.ancestor(a, b, parents) + if v: + f,n = v + return filectx(self._repo, f, fileid=n, filelog=flcache[f]) - def generations(vertex): - sg, s = None, {} - for g,v in ancestors(vertex): - if g != sg: - if sg: - yield sg, s - sg, s = g, {v:1} - else: - s[v] = 1 - 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]: - # find the intersection - i = [ n for n in gx[1] if n in gy[1] ] - if i: - fp,fn = i[0] - fl = flcache[fp] - return filectx(self._repo, fp, fileid=fn, filelog=fl) - else: - gy = y.next() - gx = x.next() - elif gx[0] < gy[0]: - gy = y.next() - else: - gx = x.next() - except StopIteration: - return None + return None
--- a/mercurial/revlog.py Tue Sep 19 15:28:13 2006 -0500 +++ b/mercurial/revlog.py Wed Sep 20 16:50:50 2006 -0500 @@ -13,7 +13,7 @@ from node import * from i18n import gettext as _ from demandload import demandload -demandload(globals(), "binascii changegroup errno heapq mdiff os") +demandload(globals(), "binascii changegroup errno ancestor mdiff os") demandload(globals(), "sha struct util zlib") # revlog version strings @@ -1016,78 +1016,10 @@ def ancestor(self, a, b): """calculate the least common ancestor of nodes a and b""" - # start with some short cuts for the linear cases - if a == b: - return a - ra = self.rev(a) - rb = self.rev(b) - if ra < rb: - last = b - first = a - else: - last = a - first = b - - # reachable won't include stop in the list, so we have to use a parent - reachable = self.reachable(last, stop=self.parents(first)[0]) - if first in reachable: - return first - - # calculate the distance of every node from root - dist = {nullid: 0} - for i in xrange(self.count()): - n = self.node(i) - p1, p2 = self.parents(n) - dist[n] = max(dist[p1], dist[p2]) + 1 + def parents(node): + return [p for p in self.parents(node) if p != nullid] - # traverse ancestors in order of decreasing distance from root - def ancestors(node): - # we store negative distances because heap returns smallest member - h = [(-dist[node], node)] - seen = {} - while h: - d, n = heapq.heappop(h) - if n not in seen: - seen[n] = 1 - yield (-d, n) - for p in self.parents(n): - heapq.heappush(h, (-dist[p], p)) - - def generations(node): - sg, s = None, {} - for g,n in ancestors(node): - if g != sg: - if sg: - yield sg, s - sg, s = g, {n:1} - else: - s[n] = 1 - 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 - while 1: - #print "ancestor gen %s %s" % (gx[0], gy[0]) - if gx[0] == gy[0]: - # find the intersection - i = [ n for n in gx[1] if n in gy[1] ] - if i: - return i[0] - else: - #print "next" - gy = y.next() - gx = x.next() - elif gx[0] < gy[0]: - #print "next y" - gy = y.next() - else: - #print "next x" - gx = x.next() + return ancestor.ancestor(a, b, parents) or nullid def group(self, nodelist, lookup, infocollect=None): """calculate a delta group