upstream/mercurial-mirror Files · mercurial/ancestor.py

clone: only use stream when we understand the revlog format...

clone: only use stream when we understand the revlog format This patch fixes issues with stream cloning in the presense of parentdelta, lwcopy and similar additions that change the interpretation of the revlog format, or the format itself. Currently, the stream capability is sent like this: stream=<version of changelog> But the client doesn't actually check the version number; also, it only checks the changelog and it doesn't capture the interpretation-changes and flag-changes in parentdelta and lwcopy. This patch removes the 'stream' capability whenever we use a non-basic revlog format, to prevent old clients from receiving incorrect data. In those cases, a new capability called 'streamreqs' is added instead. Instead of a revlog version, it comes with a list of revlog-format relevant requirements, which are a subset of the repository requirements, excluding things that are not relevant for stream. New clients use this to determine whether or not they can stream. Old clients only look for the 'stream' capability, as always. New servers will still send this when serving old repositories.

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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 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

          a, b = sorted([a, b])

          # 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

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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 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

				a, b = sorted([a, b])

				# 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