# 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 *

from i18n import _

import errno, util, os, tempfile, context, heapq

def filemerge(repo, fw, fd, fo, wctx, mctx):

    """perform a 3-way merge in the working directory

    fw = original filename in the working directory

    fd = destination filename in the working directory

    fo = filename in other parent

    wctx, mctx = working and merge changecontexts

    """

    def temp(prefix, ctx):

        pre = "%s~%s." % (os.path.basename(ctx.path()), prefix)

        (fd, name) = tempfile.mkstemp(prefix=pre)

        data = repo.wwritedata(ctx.path(), ctx.data())

        f = os.fdopen(fd, "wb")

        f.write(data)

        f.close()

        return name

    fcm = wctx.filectx(fw)

    fcmdata = wctx.filectx(fd).data()

    fco = mctx.filectx(fo)

    if not fco.cmp(fcmdata): # files identical?

        return None

    fca = fcm.ancestor(fco)

    if not fca:

        fca = repo.filectx(fw, fileid=nullrev)

    a = repo.wjoin(fd)

    b = temp("base", fca)

    c = temp("other", fco)

    if fw != fo:

        repo.ui.status(_("merging %s and %s\n") % (fw, fo))

    else:

        repo.ui.status(_("merging %s\n") % fw)

    repo.ui.debug(_("my %s other %s ancestor %s\n") % (fcm, fco, fca))

    cmd = (os.environ.get("HGMERGE") or repo.ui.config("ui", "merge")

           or "hgmerge")

    r = util.system('%s "%s" "%s" "%s"' % (cmd, a, b, c), cwd=repo.root,

                    environ={'HG_FILE': fd,

                             'HG_MY_NODE': str(wctx.parents()[0]),

                             'HG_OTHER_NODE': str(mctx)})

    if r:

        repo.ui.warn(_("merging %s failed!\n") % fd)

    os.unlink(b)

    os.unlink(c)

    return r

def checkunknown(wctx, mctx):

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

    man = mctx.manifest()

    for f in wctx.unknown():

        if f in man:

            if mctx.filectx(f).cmp(wctx.filectx(f).data()):

                raise util.Abort(_("untracked local file '%s' differs"

                                   " from remote version") % f)

def checkcollision(mctx):

    "check for case folding collisions in the destination context"

    folded = {}

    for fn in mctx.manifest():

        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):

    """

    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.

    """

    action = []

    man = mctx.manifest()

    for f in wctx.deleted() + wctx.removed():

        if f not in man:

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

    return action

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

    """

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

    """

    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

    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)

    def findold(fctx):

        "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

    copy = {}

    fullcopy = {}

    diverge = {}

    def checkcopies(c, man, aman):

        '''check possible copies for filectx c'''

        for of in findold(c):

            fullcopy[c.path()] = of # remember for dir rename detection

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

                if of in ma:

                    diverge.setdefault(of, []).append(c.path())

                continue

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

            # no merge needed

            if man[of] == aman.get(of):

                continue

            c2 = ctx(of, man[of])

            ca = c.ancestor(c2)

            if not ca: # unrelated?

                continue

            # named changed on only one side?

            if ca.path() == c.path() or ca.path() == c2.path():

                if c == ca or c2 == ca: # no merge needed, ignore copy

                    continue

                copy[c.path()] = of

    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 {}, {}

    u1 = nonoverlap(m1, m2, ma)

    u2 = nonoverlap(m2, m1, ma)

    for f in u1:

        checkcopies(ctx(f, m1[f]), m2, ma)

    for f in u2:

        checkcopies(ctx(f, m2[f]), m1, ma)

    d2 = {}

    for of, fl in diverge.items():

        for f in fl:

            fo = list(fl)

            fo.remove(f)

            d2[f] = (of, fo)

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

        return copy, diverge

    # 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

    # 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):]

                    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, b, c = ma.execf(fa), m1.execf(f), m2.execf(f2)

        if ((a^b) | (a^c)) ^ a:

            return 'x'

        a, b, c = ma.linkf(fa), m1.linkf(f), m2.linkf(f2)

        if ((a^b) | (a^c)) ^ a:

            return 'l'

        return ''

    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:

            # are files different?

            if n != m2[f]:

                a = ma.get(f, nullid)

                # are both different from the ancestor?

                if not overwrite and n != a and m2[f] != a:

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