Simplify/correct finding the hg executable (fixes issue644)
Simply use find_exe('hg') as the default value for $HG and require to manually
set it if you have special requirements.
While the default will not always be 100% correct (i.e. the identical hg
version) for many users it is and for the others the hg executable found in
the PATH should do most things correctly.
Developers or other users with multiple installs can set $HG or run something
like util.set_hgexecutable in their shell or python scripts.
Additionally util.hgexecutable() is now available so extensions can access
the value with a public interface, too.
# 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