# 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

def _droponode(data):

    # used for compatibility for v1

    bits = data.split("\0")

    bits = bits[:-2] + bits[-1:]

    return "\0".join(bits)

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 length `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()

        oldv2 = set() # old format version of v2 record

        for rec in v2records:

            if rec[0] == 'L':

                oldv2.add(rec)

            elif rec[0] == 'F':

                # drop the onode data (not contained in v1)

                oldv2.add(('F', _droponode(rec[1])))

        for rec in v1records:

            if rec not in oldv2:

                # 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()))

                # add place holder "other" file node information

                # nobody is using it yet so we do no need to fetch the data

                # if mctx was wrong `mctx[bits[-2]]` may fails.

                for idx, r in enumerate(v1records):

                    if r[0] == 'F':

                        bits = r[1].split("\0")

                        bits.insert(-2, '')

                        v1records[idx] = (r[0], "\0".join(bits))

                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

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

                off += 4

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

                off += length

                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.write("%s\n" % _droponode(data))

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

                           fca.path(), hex(fca.filenode()),

                           fco.path(), hex(fco.filenode()),

                           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 files(self):

        return self._state.keys()

    def mark(self, dfile, state):

        self._state[dfile][0] = state

        self._dirty = True

    def resolve(self, dfile, wctx):

        if self[dfile] == 'r':

            return 0

        stateentry = self._state[dfile]

        state, hash, lfile, afile, anode, ofile, onode, flags = stateentry

        octx = self._repo[self._other]

        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))