mercurial/ancestor.py

inotify: server: refactor updatestatus()

* Instead of one entry point, use two entry points, updatefile()
  and deletefile(), both internally calling the helper function _updatestatus
* Do not rely on TypeError to detect the type of oldstatus: use isinstance
* The call updatestatus(wpath, None) in deleted() was a bit particular:
  because no osstat and no newstatus was given, the newstatus was determined
  using the data stored internally. To replace this exact behavior with the
  new code, one would use:
    root, fn = self.split(wpath)
    d = self.dir(self.tree, root)
    self.filedeleted(wpath, d.get(fn))
  This, however, duplicates code with _updatestatus(), which led us to an
  interesting question: why are we basing ourselves on repowatcher data to
  update the status, where everywhere else, we are comparing against dirsate?
  There is no reason to do this, which is why the new code is:
    self.filedeleted(wpath, self.repo.dirstate[wpath])
  Incidentally, after this, the test for issue1371 passes again.

# 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, 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
    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