# 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.

import struct

from node import nullid, nullrev, hex, bin

from i18n import _

from mercurial import obsolete

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

import errno, os, shutil

_pack = struct.pack

_unpack = struct.unpack

class mergestate(object):

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

    it is stored on disk when needed. Two file are used, one with an old

    format, one with a new format. Both contains similar data, but the new

    format can store new kind of field.

    Current new format is a list of arbitrary record of the form:

        [type][length][content]

    Type is a single character, length is a 4 bytes integer, content is an

    arbitrary suites of bytes of lenght `length`.

    Type should be a letter. Capital letter are mandatory record, Mercurial

    should abort if they are unknown. lower case record can be safely ignored.

    Currently known record:

    L: the node of the "local" part of the merge (hexified version)

    O: the node of the "other" part of the merge (hexified version)

    F: a file to be merged entry

    '''

    statepathv1 = "merge/state"

    statepathv2 = "merge/state2"

    def __init__(self, repo):

        self._repo = repo

        self._dirty = False

        self._read()

    def reset(self, node=None, other=None):

        self._state = {}

        if node:

            self._local = node

            self._other = other

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

        self._dirty = False

    def _read(self):

        self._state = {}

        records = self._readrecords()

        for rtype, record in records:

            if rtype == 'L':

                self._local = bin(record)

            elif rtype == 'O':

                self._other = bin(record)

            elif rtype == "F":

                bits = record.split("\0")

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

            elif not rtype.islower():

                raise util.Abort(_('unsupported merge state record:'

                                   % rtype))

        self._dirty = False

    def _readrecords(self):

        v1records = self._readrecordsv1()

        v2records = self._readrecordsv2()

                # v1 file is newer than v2 file, use it

                # we have to infer the "other" changeset of the merge

                # we cannot do better than that with v1 of the format

                mctx = self._repo[None].parents()[-1]

                v1records.append(('O', mctx.hex()))

                return v1records

        else:

            return v2records

    def _readrecordsv1(self):

        records = []

        try:

            f = self._repo.opener(self.statepathv1)

            for i, l in enumerate(f):

                if i == 0:

                    records.append(('L', l[:-1]))

                else:

                    records.append(('F', l[:-1]))

            f.close()

        except IOError, err:

            if err.errno != errno.ENOENT:

                raise

        return records

    def _readrecordsv2(self):

        records = []

        try:

            f = self._repo.opener(self.statepathv2)

            data = f.read()

            off = 0

            end = len(data)

            while off < end:

                rtype = data[off]

                off += 1

                lenght = _unpack('>I', data[off:(off + 4)])[0]

                off += 4

                record = data[off:(off + lenght)]

                off += lenght

                records.append((rtype, record))

            f.close()

        except IOError, err:

            if err.errno != errno.ENOENT:

                raise

        return records

    def commit(self):

        if self._dirty:

            records = []

            records.append(("L", hex(self._local)))

            records.append(("O", hex(self._other)))

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

                records.append(("F", "\0".join([d] + v)))

            self._writerecords(records)

            self._dirty = False

    def _writerecords(self, records):

        self._writerecordsv1(records)

        self._writerecordsv2(records)

    def _writerecordsv1(self, records):

        f = self._repo.opener(self.statepathv1, "w")

        irecords = iter(records)

        lrecords = irecords.next()

        assert lrecords[0] == 'L'

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

        for rtype, data in irecords:

            if rtype == "F":

        f.close()

    def _writerecordsv2(self, records):

        f = self._repo.opener(self.statepathv2, "w")

        for key, data in records:

            assert len(key) == 1

            format = ">sI%is" % len(data)

            f.write(_pack(format, key, len(data), data))

        f.close()

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

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

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

        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 files(self):

        return self._state.keys()

    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

        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.wopener.audit.check(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 _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

def _checkcollision(repo, wmf, actions, prompts):

    # build provisional merged manifest up

    pmmf = set(wmf)

    def addop(f, args):

        pmmf.add(f)

    def removeop(f, args):

        pmmf.discard(f)

    def nop(f, args):

        pass

    def renameop(f, args):

        f2, fd, flags = args

        if f:

            pmmf.discard(f)

        pmmf.add(fd)

    def mergeop(f, args):

        f2, fd, move = args

        if move:

            pmmf.discard(f)

        pmmf.add(fd)

    opmap = {

        "a": addop,

        "d": renameop,

        "dr": nop,

        "e": nop,

        "f": addop, # untracked file should be kept in working directory

        "g": addop,

        "m": mergeop,

        "r": removeop,

        "rd": nop,

    }

    for f, m, args, msg in actions:

        op = opmap.get(m)

        assert op, m

        op(f, args)

    opmap = {

        "cd": addop,

        "dc": addop,

    }

    for f, m in prompts:

        op = opmap.get(m)

        assert op, m

        op(f, None)

    # check case-folding collision in provisional merged manifest

    foldmap = {}

    for f in sorted(pmmf):

        fold = util.normcase(f)

        if fold in foldmap:

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

                             % (f, foldmap[fold]))

        foldmap[fold] = f

def manifestmerge(repo, wctx, p2, pa, branchmerge, force, partial,

                  acceptremote=False):

    """

    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

    acceptremote = accept the incoming changes without prompting

    """

    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

    fdiff = dicthelpers.diff(m1, m2)

    flagsdiff = m1.flagsdiff(m2)

    diff12 = dicthelpers.join(fdiff, flagsdiff)

    for f, (n12, fl12) in diff12.iteritems():

        if n12:

            n1, n2 = n12

        else: # file contents didn't change, but flags did

            n1 = n2 = m1.get(f, None)

            if n1 is None:

                # Since n1 == n2, the file isn't present in m2 either. This

                # means that the file was removed or deleted locally and

                # removed remotely, but that residual entries remain in flags.

                # This can happen in manifests generated by workingctx.

                continue

        if fl12:

            fl1, fl2 = fl12

        else: # flags didn't change, file contents did

            fl1 = fl2 = m1.flags(f)

        if partial and not partial(f):

            continue

        if n1 and n2:

            fla = ma.flags(f)

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

            a = ma.get(f, nullid)

            if n2 == a and fl2 == fla:

                pass # remote unchanged - keep local

            elif n1 == a and fl1 == fla: # local unchanged - use remote

                if n1 == 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 n1 == 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 n1 and f in movewithdir: # directory rename

            f2 = movewithdir[f]

            actions.append((f, "d", (None, f2, fl1),

                            "remote renamed directory to " + f2))

        elif n1 and f in copy:

            f2 = copy[f]

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

                            "local copied/moved to " + f2))

        elif n1 and f in ma: # clean, a different, no remote

            if n1 != ma[f]:

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

            elif n1[20:] == "a": # added, no remote

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

            else:

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

        elif n2 and f in movewithdir:

            f2 = movewithdir[f]

            actions.append((None, "d", (f, f2, fl2),

                            "local renamed directory to " + f2))

        elif n2 and 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 n2 and 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", (fl2,), "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", (fl2,), "remote created"))

        elif n2 and n2 != ma[f]:

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

            if not force and different:

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

            else:

                # if different: old untracked f may be overwritten and lost

                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"))

    if not util.checkcase(repo.path):

        # check collision between files only in p2 for clean update