# merge.py - directory-level update/merge handling for Mercurial

#

# Copyright 2006, 2007 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.

from node import nullid, nullrev

from i18n import _

import errno, util, os, heapq, filemerge

def _checkunknown(wctx, mctx):

    "check for collisions between unknown files and files in mctx"

    for f in wctx.unknown():

def _checkcollision(mctx):

    "check for case folding collisions in the destination context"

    folded = {}

        fold = fn.lower()

        if fold in folded:

            raise util.Abort(_("case-folding collision between %s and %s")

                             % (fn, folded[fold]))

        folded[fold] = fn

def _forgetremoved(wctx, mctx, branchmerge):

    """

    Forget removed files

    If we're jumping between revisions (as opposed to merging), and if

    neither the working directory nor the target rev has the file,

    then we need to remove it from the dirstate, to prevent the

    dirstate from listing the file when it is no longer in the

    manifest.

    If we're merging, and the other revision has removed a file

    that is not present in the working directory, we need to mark it

    as removed.

    """

    action = []

    state = branchmerge and 'r' or 'f'

    for f in wctx.deleted():

            action.append((f, state))

    if not branchmerge:

        for f in wctx.removed():

                action.append((f, "f"))

    return action

def _nonoverlap(d1, d2, d3):

    "Return list of elements in d1 not in d2 or d3"

    l = [d for d in d1 if d not in d3 and d not in d2]

    l.sort()

    return l

def _dirname(f):

    s = f.rfind("/")

    if s == -1:

        return ""

    return f[:s]

def _dirs(files):

    d = {}

    for f in files:

        f = _dirname(f)

        while f not in d:

            d[f] = True

            f = _dirname(f)

    return d

def _findoldnames(fctx, limit):

    "find files that path was copied from, back to linkrev limit"

    old = {}

    seen = {}

    orig = fctx.path()

    visit = [fctx]

    while visit:

        fc = visit.pop()

        s = str(fc)

        if s in seen:

            continue

        seen[s] = 1

        if fc.path() != orig and fc.path() not in old:

            old[fc.path()] = 1

        if fc.rev() < limit:

            continue

        visit += fc.parents()

    old = old.keys()

    old.sort()

    return old

def findcopies(repo, m1, m2, ma, limit):

    """

    Find moves and copies between m1 and m2 back to limit linkrev

    """

    wctx = repo.workingctx()

    def makectx(f, n):

        if len(n) == 20:

            return repo.filectx(f, fileid=n)

        return wctx.filectx(f)

    ctx = util.cachefunc(makectx)

    copy = {}

    fullcopy = {}

    diverge = {}

    def checkcopies(f, m1, m2):

        '''check possible copies of f from m1 to m2'''

        c1 = ctx(f, m1[f])

        for of in _findoldnames(c1, limit):

            fullcopy[f] = of # remember for dir rename detection

            if of in m2: # original file not in other manifest?

                # if the original file is unchanged on the other branch,

                # no merge needed

                if m2[of] != ma.get(of):

                    c2 = ctx(of, m2[of])

                    ca = c1.ancestor(c2)

                    # related and named changed on only one side?

                    if ca and ca.path() == f or ca.path() == c2.path():

                        if c1 != ca or c2 != ca: # merge needed?

                            copy[f] = of

            elif of in ma:

                diverge.setdefault(of, []).append(f)

    if not repo.ui.configbool("merge", "followcopies", True):

        return {}, {}

    # avoid silly behavior for update from empty dir

    if not m1 or not m2 or not ma:

        return {}, {}

    repo.ui.debug(_("  searching for copies back to rev %d\n") % limit)

    u1 = _nonoverlap(m1, m2, ma)

    u2 = _nonoverlap(m2, m1, ma)

    if u1:

        repo.ui.debug(_("  unmatched files in local:\n   %s\n")

                      % "\n   ".join(u1))

    if u2:

        repo.ui.debug(_("  unmatched files in other:\n   %s\n")

                      % "\n   ".join(u2))

    for f in u1:

        checkcopies(f, m1, m2)

    for f in u2:

        checkcopies(f, m2, m1)

    diverge2 = {}

    for of, fl in diverge.items():

        if len(fl) == 1:

            del diverge[of] # not actually divergent

        else:

            diverge2.update(dict.fromkeys(fl)) # reverse map for below

    if fullcopy:

        repo.ui.debug(_("  all copies found (* = to merge, ! = divergent):\n"))

        for f in fullcopy:

            note = ""

            if f in copy: note += "*"

            if f in diverge2: note += "!"

            repo.ui.debug(_("   %s -> %s %s\n") % (f, fullcopy[f], note))

    del diverge2

    if not fullcopy or not repo.ui.configbool("merge", "followdirs", True):

        return copy, diverge

    repo.ui.debug(_("  checking for directory renames\n"))

    # generate a directory move map

    d1, d2 = _dirs(m1), _dirs(m2)

    invalid = {}

    dirmove = {}

    # examine each file copy for a potential directory move, which is

    # when all the files in a directory are moved to a new directory

    for dst, src in fullcopy.items():

        dsrc, ddst = _dirname(src), _dirname(dst)

        if dsrc in invalid:

            # already seen to be uninteresting

            continue

        elif dsrc in d1 and ddst in d1:

            # directory wasn't entirely moved locally

            invalid[dsrc] = True

        elif dsrc in d2 and ddst in d2:

            # directory wasn't entirely moved remotely

            invalid[dsrc] = True

        elif dsrc in dirmove and dirmove[dsrc] != ddst:

            # files from the same directory moved to two different places

            invalid[dsrc] = True

        else:

            # looks good so far

            dirmove[dsrc + "/"] = ddst + "/"

    for i in invalid:

        if i in dirmove:

            del dirmove[i]

    del d1, d2, invalid

    if not dirmove:

        return copy, diverge

    for d in dirmove:

        repo.ui.debug(_("  dir %s -> %s\n") % (d, dirmove[d]))

    # check unaccounted nonoverlapping files against directory moves

    for f in u1 + u2:

        if f not in fullcopy:

            for d in dirmove:

                if f.startswith(d):

                    # new file added in a directory that was moved, move it

                    copy[f] = dirmove[d] + f[len(d):]

                    repo.ui.debug(_("  file %s -> %s\n") % (f, copy[f]))

                    break

    return copy, diverge

def _symmetricdifference(repo, rev1, rev2):

    """symmetric difference of the sets of ancestors of rev1 and rev2

    I.e. revisions that are ancestors of rev1 or rev2, but not both.

    """

    # basic idea:

    # - mark rev1 and rev2 with different colors

    # - walk the graph in topological order with the help of a heap;

    #   for each revision r:

    #     - if r has only one color, we want to return it

    #     - add colors[r] to its parents

    #

    # We keep track of the number of revisions in the heap that

    # we may be interested in.  We stop walking the graph as soon

    # as this number reaches 0.

    WHITE = 1

    BLACK = 2

    ALLCOLORS = WHITE | BLACK

    colors = {rev1: WHITE, rev2: BLACK}

    cl = repo.changelog

    visit = [-rev1, -rev2]

    heapq.heapify(visit)

    n_wanted = len(visit)

    ret = []

    while n_wanted:

        r = -heapq.heappop(visit)

        wanted = colors[r] != ALLCOLORS

        n_wanted -= wanted

        if wanted:

            ret.append(r)

        for p in cl.parentrevs(r):

            if p == nullrev:

                continue

            if p not in colors:

                # first time we see p; add it to visit

                n_wanted += wanted

                colors[p] = colors[r]

                heapq.heappush(visit, -p)

            elif colors[p] != ALLCOLORS and colors[p] != colors[r]:

                # at first we thought we wanted p, but now

                # we know we don't really want it

                n_wanted -= 1

                colors[p] |= colors[r]

        del colors[r]

    return ret

def manifestmerge(repo, p1, p2, pa, overwrite, partial):

    """

    Merge p1 and p2 with ancestor ma and generate merge action list

    overwrite = whether we clobber working files

    partial = function to filter file lists

    """

    repo.ui.note(_("resolving manifests\n"))

    repo.ui.debug(_(" overwrite %s partial %s\n") % (overwrite, bool(partial)))

    repo.ui.debug(_(" ancestor %s local %s remote %s\n") % (pa, p1, p2))

    m1 = p1.manifest()

    m2 = p2.manifest()

    ma = pa.manifest()

    backwards = (pa == p2)

    action = []

    copy = {}

    diverge = {}

    def fmerge(f, f2=None, fa=None):

        """merge flags"""

        if not f2:

            f2 = f

            fa = f

        a, m, n = ma.flags(fa), m1.flags(f), m2.flags(f2)

        if m == n: # flags agree

            return m # unchanged

        if m and n: # flags are set but don't agree

            if not a: # both differ from parent

                r = repo.ui.prompt(

                    _(" conflicting flags for %s\n"

                      "(n)one, e(x)ec or sym(l)ink?") % f, "[nxl]", "n")

                return r != "n" and r or ''

            if m == a:

                return n # changed from m to n

            return m # changed from n to m

        if m and m != a: # changed from a to m

            return m

        if n and n != a: # changed from a to n

            return n

        return '' # flag was cleared

    def act(msg, m, f, *args):

        repo.ui.debug(" %s: %s -> %s\n" % (f, msg, m))

        action.append((f, m) + args)

    if not (backwards or overwrite):

        rev1 = p1.rev()

        if rev1 is None:

            # p1 is a workingctx

            rev1 = p1.parents()[0].rev()

        limit = min(_symmetricdifference(repo, rev1, p2.rev()))

        copy, diverge = findcopies(repo, m1, m2, ma, limit)

    for of, fl in diverge.items():

        act("divergent renames", "dr", of, fl)

    copied = dict.fromkeys(copy.values())

    # Compare manifests

    for f, n in m1.iteritems():

        if partial and not partial(f):

            continue

        if f in m2:

            if overwrite or backwards:

                rflags = m2.flags(f)

            else:

                rflags = fmerge(f)

            # are files different?

            if n != m2[f]:

                a = ma.get(f, nullid)

                # are we clobbering?

                if overwrite:

                    act("clobbering", "g", f, rflags)

                # or are we going back in time and clean?

                elif backwards and not n[20:]:

                    act("reverting", "g", f, rflags)

                # are both different from the ancestor?

                elif n != a and m2[f] != a:

                    act("versions differ", "m", f, f, f, rflags, False)

                # is remote's version newer?

                elif m2[f] != a:

                    act("remote is newer", "g", f, rflags)

                # local is newer, not overwrite, check mode bits

                elif m1.flags(f) != rflags:

                    act("update permissions", "e", f, rflags)

            # contents same, check mode bits