view mercurial/ancestor.py @ 17245:6e84171a61c8 stable

largefiles: fix path handling for cp/mv (issue3516)

Previously, a copy or a move of a largefile only worked if the cwd was the root
of the repository.  The first issue was that the destination path passed to
os.mkdirs() chopped the absolute path to the standin after '.hglf/', which
essentially created a path relative to the repository root.  Similarly, the
second issue was that the source and dest paths for copyfile() were relative to
the repo root.  This converts these three paths to absolute paths.

Some notable issues, regardless of the directory in which the cp/mv is executed:

1) The copy is not being recorded in lfdirstate, but it is in dirstate for the
standins.  I'm not sure if this is by design (i.e. minimal info in lfdirstate).

2) status -C doesn't behave as expected.  Using the testcase as an example:

  # after mv + ci
  $ hg status -C -v --rev '.^'     # expected to see 'A' and ' ' lines too
  R dira\dirb\largefile

  $ hg status -C -v --rev '.^' foo/largefile
  # no output                      # expected to see 'A' and ' ' lines only

  $ hg status -C -v --rev '.^' foo/
  # no output                      # expected to see 'A', ' ' and 'R' lines

  $ hg status -C -v --rev '.^' ./  # expected to see 'A' and ' ' lines too
  R dirb\largefile

  $ hg status -C -v --rev '.^' ../.hglf/dira/foo/largefile
  A ..\.hglf\dira\foo\largefile
    ..\.hglf\dira\dirb\largefile  # no 'R' expected when new file is specified

  $ hg status -C -v --rev '.^' ../.hglf   # OK
  A ..\.hglf\dira\foo\largefile
    ..\.hglf\dira\dirb\largefile
  R ..\.hglf\dira\dirb\largefile

# ancestor.py - generic DAG ancestor algorithm for mercurial
#
# Copyright 2006 Matt Mackall <[e-mail]>
#
# 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):
    """
    Returns the common ancestor of a and b that is furthest from a
    root (as measured by longest path) or None if no ancestor is
    found. If there are multiple common ancestors at the same
    distance, the first one found is returned.

    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
    # depth is stored as a negative for heapq
    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:
                # -(maximum distance of parents + 1)
                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 True:
            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