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
--- /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