# 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 version 2 or any later version.

from node import nullid, nullrev, hex, bin

from i18n import _

import error, util, filemerge, copies, subrepo, worker

import errno, os, shutil

class mergestate(object):

    '''track 3-way merge state of individual files'''

    def __init__(self, repo):

        self._repo = repo

        self._dirty = False

        self._read()

    def reset(self, node=None):

        self._state = {}

        if node:

            self._local = node

        shutil.rmtree(self._repo.join("merge"), True)

        self._dirty = False

    def _read(self):

        self._state = {}

        try:

            f = self._repo.opener("merge/state")

            for i, l in enumerate(f):

                if i == 0:

                    self._local = bin(l[:-1])

                else:

                    bits = l[:-1].split("\0")

                    self._state[bits[0]] = bits[1:]

            f.close()

        except IOError, err:

            if err.errno != errno.ENOENT:

                raise

        self._dirty = False

    def commit(self):

        if self._dirty:

            f = self._repo.opener("merge/state", "w")

            f.write(hex(self._local) + "\n")

            for d, v in self._state.iteritems():

                f.write("\0".join([d] + v) + "\n")

            f.close()

            self._dirty = False

    def add(self, fcl, fco, fca, fd):

        hash = util.sha1(fcl.path()).hexdigest()

        self._repo.opener.write("merge/" + hash, fcl.data())

        self._state[fd] = ['u', hash, fcl.path(), fca.path(),

                           hex(fca.filenode()), fco.path(), fcl.flags()]

        self._dirty = True

    def __contains__(self, dfile):

        return dfile in self._state

    def __getitem__(self, dfile):

        return self._state[dfile][0]

    def __iter__(self):

        l = self._state.keys()

        l.sort()

        for f in l:

            yield f

    def mark(self, dfile, state):

        self._state[dfile][0] = state

        self._dirty = True

    def resolve(self, dfile, wctx, octx):

        if self[dfile] == 'r':

            return 0

        state, hash, lfile, afile, anode, ofile, flags = self._state[dfile]

        fcd = wctx[dfile]

        fco = octx[ofile]

        fca = self._repo.filectx(afile, fileid=anode)

        # "premerge" x flags

        flo = fco.flags()

        fla = fca.flags()

        if 'x' in flags + flo + fla and 'l' not in flags + flo + fla:

            if fca.node() == nullid:

                self._repo.ui.warn(_('warning: cannot merge flags for %s\n') %

                                   afile)

            elif flags == fla:

                flags = flo

        # restore local

        f = self._repo.opener("merge/" + hash)

        self._repo.wwrite(dfile, f.read(), flags)

        f.close()

        r = filemerge.filemerge(self._repo, self._local, lfile, fcd, fco, fca)

        if r is None:

            # no real conflict

            del self._state[dfile]

        elif not r:

            self.mark(dfile, 'r')

        return r

def _checkunknownfile(repo, wctx, mctx, f):

    return (not repo.dirstate._ignore(f)

        and os.path.isfile(repo.wjoin(f))

        and repo.dirstate.normalize(f) not in repo.dirstate

        and mctx[f].cmp(wctx[f]))

def _checkunknown(repo, wctx, mctx):

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

    error = False

    for f in mctx:

        if f not in wctx and _checkunknownfile(repo, wctx, mctx, f):

            error = True

            wctx._repo.ui.warn(_("%s: untracked file differs\n") % f)

    if error:

        raise util.Abort(_("untracked files in working directory differ "

                           "from files in requested revision"))

def _remains(f, m, ma, workingctx=False):

    """check whether specified file remains after merge.

    It is assumed that specified file is not contained in the manifest

    of the other context.

    """

    if f in ma:

        n = m[f]

        if n != ma[f]:

            return True # because it is changed locally

            # even though it doesn't remain, if "remote deleted" is

            # chosen in manifestmerge()

        elif workingctx and n[20:] == "a":

            return True # because it is added locally (linear merge specific)

        else:

            return False # because it is removed remotely

    else:

        return True # because it is added locally

def _checkcollision(mctx, extractxs):

    "check for case folding collisions in the destination context"

    folded = {}

    for fn in mctx:

        fold = util.normcase(fn)

        if fold in folded:

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

                             % (fn, folded[fold]))

        folded[fold] = fn

    if extractxs:

        wctx, actx = extractxs

        # class to delay looking up copy mapping

        class pathcopies(object):

            @util.propertycache

            def map(self):

                # {dst@mctx: src@wctx} copy mapping

                return copies.pathcopies(wctx, mctx)

        pc = pathcopies()

        for fn in wctx:

            fold = util.normcase(fn)

            mfn = folded.get(fold, None)

            if (mfn and mfn != fn and pc.map.get(mfn) != fn and

                _remains(fn, wctx.manifest(), actx.manifest(), True) and

                _remains(mfn, mctx.manifest(), actx.manifest())):

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

                                 % (mfn, 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.

    """

    actions = []

    state = branchmerge and 'r' or 'f'

    for f in wctx.deleted():

        if f not in mctx:

            actions.append((f, state, None, "forget deleted"))

    if not branchmerge:

        for f in wctx.removed():

            if f not in mctx:

                actions.append((f, "f", None, "forget removed"))

    return actions

    """

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

    branchmerge and force are as passed in to update

    partial = function to filter file lists

    """

    overwrite = force and not branchmerge

    actions, copy, movewithdir = [], {}, {}

    followcopies = False

    if overwrite:

        pa = wctx

    elif pa == p2: # backwards

        pa = wctx.p1()

    elif not branchmerge and not wctx.dirty(missing=True):

        pass

    elif pa and repo.ui.configbool("merge", "followcopies", True):

        followcopies = True

    # manifests fetched in order are going to be faster, so prime the caches

    [x.manifest() for x in

     sorted(wctx.parents() + [p2, pa], key=lambda x: x.rev())]

    if followcopies:

        ret = copies.mergecopies(repo, wctx, p2, pa)

        copy, movewithdir, diverge, renamedelete = ret

        for of, fl in diverge.iteritems():

            actions.append((of, "dr", (fl,), "divergent renames"))

        for of, fl in renamedelete.iteritems():

            actions.append((of, "rd", (fl,), "rename and delete"))

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

    repo.ui.debug(" branchmerge: %s, force: %s, partial: %s\n"

                  % (bool(branchmerge), bool(force), bool(partial)))

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

    m1, m2, ma = wctx.manifest(), p2.manifest(), pa.manifest()

    copied = set(copy.values())

    copied.update(movewithdir.values())

    if '.hgsubstate' in m1:

        # check whether sub state is modified

        for s in sorted(wctx.substate):

            if wctx.sub(s).dirty():

                m1['.hgsubstate'] += "+"

                break

    aborts, prompts = [], []

    # Compare manifests

    for f, n in m1.iteritems():

        if partial and not partial(f):

            continue

        if f in m2:

            n2 = m2[f]

            fl1, fl2, fla = m1.flags(f), m2.flags(f), ma.flags(f)

            nol = 'l' not in fl1 + fl2 + fla

            a = ma.get(f, nullid)

            if n == n2 and fl1 == fl2:

                pass # same - keep local

            elif n2 == a and fl2 == fla:

                pass # remote unchanged - keep local

            elif n == a and fl1 == fla: # local unchanged - use remote

                if n == n2: # optimization: keep local content

                    actions.append((f, "e", (fl2,), "update permissions"))

                else:

                    actions.append((f, "g", (fl2,), "remote is newer"))

            elif nol and n2 == a: # remote only changed 'x'

                actions.append((f, "e", (fl2,), "update permissions"))

            elif nol and n == a: # local only changed 'x'

                actions.append((f, "g", (fl1,), "remote is newer"))

            else: # both changed something

                actions.append((f, "m", (f, f, False), "versions differ"))

        elif f in copied: # files we'll deal with on m2 side

            pass

        elif f in movewithdir: # directory rename

            f2 = movewithdir[f]

            actions.append((f, "d", (None, f2, m1.flags(f)),

                            "remote renamed directory to " + f2))

        elif f in copy:

            f2 = copy[f]

            actions.append((f, "m", (f2, f, False),

                            "local copied/moved to " + f2))

        elif f in ma: # clean, a different, no remote

            if n != ma[f]:

                prompts.append((f, "cd")) # prompt changed/deleted

            elif n[20:] == "a": # added, no remote

                actions.append((f, "f", None, "remote deleted"))

            else:

                actions.append((f, "r", None, "other deleted"))

    for f, n in m2.iteritems():

        if partial and not partial(f):

            continue

        if f in m1 or f in copied: # files already visited

            continue

        if f in movewithdir:

            f2 = movewithdir[f]

            actions.append((None, "d", (f, f2, m2.flags(f)),

                            "local renamed directory to " + f2))

        elif f in copy:

            f2 = copy[f]

            if f2 in m2:

                actions.append((f2, "m", (f, f, False),

                                "remote copied to " + f))

            else:

                actions.append((f2, "m", (f, f, True),

                                "remote moved to " + f))

        elif f not in ma:

            # local unknown, remote created: the logic is described by the

            # following table:

            #

            # force  branchmerge  different  |  action

            #   n         *           n      |    get

            #   n         *           y      |   abort

            #   y         n           *      |    get

            #   y         y           n      |    get

            #   y         y           y      |   merge

            #

            # Checking whether the files are different is expensive, so we

            # don't do that when we can avoid it.

            if force and not branchmerge:

                actions.append((f, "g", (m2.flags(f),), "remote created"))

            else:

                different = _checkunknownfile(repo, wctx, p2, f)

                if force and branchmerge and different:

                    actions.append((f, "m", (f, f, False),

                                    "remote differs from untracked local"))

                elif not force and different:

                    aborts.append((f, "ud"))

                else:

                    actions.append((f, "g", (m2.flags(f),), "remote created"))

        elif n != ma[f]:

            prompts.append((f, "dc")) # prompt deleted/changed

    for f, m in sorted(aborts):

        if m == "ud":

            repo.ui.warn(_("%s: untracked file differs\n") % f)

        else: assert False, m

    if aborts:

        raise util.Abort(_("untracked files in working directory differ "

                           "from files in requested revision"))

    for f, m in sorted(prompts):

        if m == "cd":

                _("local changed %s which remote deleted\n"

                  "use (c)hanged version or (d)elete?") % f,

                (_("&Changed"), _("&Delete")), 0):

                actions.append((f, "r", None, "prompt delete"))

            else:

                actions.append((f, "a", None, "prompt keep"))

        elif m == "dc":