# 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 util, filemerge, copies, subrepo

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:]

        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")

            self._dirty = False

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

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

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

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

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

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

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

        fcd = wctx[dfile]

        fco = octx[ofile]

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

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

        if not r:

            self.mark(dfile, 'r')

        return r

def _checkunknown(wctx, mctx):

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

    for f in wctx.unknown():

        if f in mctx and mctx[f].cmp(wctx[f]):

            raise util.Abort(_("untracked file in working directory differs"

                               " from file in requested revision: '%s'") % f)

def _checkcollision(mctx):

    "check for case folding collisions in the destination context"

    folded = {}

    for fn in mctx:

        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():

        if f not in mctx:

            action.append((f, state))

    if not branchmerge:

        for f in wctx.removed():

            if f not in mctx:

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

    return action

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

    """

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

    overwrite = whether we clobber working files

    partial = function to filter file lists

    """

    def fmerge(f, f2, fa):

        """merge flags"""

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

        if m == n: # flags agree

            return m # unchanged

        if m and n and not a: # flags set, don't agree, differ from parent

            r = repo.ui.promptchoice(

                _(" conflicting flags for %s\n"

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

                (_("&None"), _("E&xec"), _("Sym&link")), 0)

            if r == 1:

                return "x" # Exec

            if r == 2:

                return "l" # Symlink

            return ""

        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)

    action, copy = [], {}

    if overwrite:

        pa = p1

    elif pa == p2: # backwards

        pa = p1.p1()

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

        dirs = repo.ui.configbool("merge", "followdirs", True)

        copy, diverge = copies.copies(repo, p1, p2, pa, dirs)

        for of, fl in diverge.iteritems():

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

    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, m2, ma = p1.manifest(), p2.manifest(), pa.manifest()

    copied = set(copy.values())

    if '.hgsubstate' in m1:

        # check whether sub state is modified

        for s in p1.substate:

            if p1.sub(s).dirty():

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

                break

    # Compare manifests

    for f, n in m1.iteritems():

        if partial and not partial(f):

            continue

        if f in m2:

            rflags = fmerge(f, f, f)

            a = ma.get(f, nullid)

            if n == m2[f] or m2[f] == a: # same or local newer

                # is file locally modified or flags need changing?

                # dirstate flags may need to be made current

                if m1.flags(f) != rflags or n[20:]:

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

            elif n == a: # remote newer

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

            else: # both changed

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

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

            pass

        elif f in copy:

            f2 = copy[f]

            if f2 not in m2: # directory rename

                act("remote renamed directory to " + f2, "d",

                    f, None, f2, m1.flags(f))

            else: # case 2 A,B/B/B or case 4,21 A/B/B

                act("local copied/moved to " + f2, "m",

                    f, f2, f, fmerge(f, f2, f2), False)

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

            if n != ma[f]:

                if repo.ui.promptchoice(

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

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

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

                    act("prompt delete", "r", f)

                else:

                    act("prompt keep", "a", f)

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

                act("remote deleted", "f", f)

            elif n[20:] != "u":

                act("other deleted", "r", f)

    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 copy:

            f2 = copy[f]

            if f2 not in m1: # directory rename

                act("local renamed directory to " + f2, "d",

                    None, f, f2, m2.flags(f))

            elif f2 in m2: # rename case 1, A/A,B/A

                act("remote copied to " + f, "m",

                    f2, f, f, fmerge(f2, f, f2), False)

            else: # case 3,20 A/B/A

                act("remote moved to " + f, "m",

                    f2, f, f, fmerge(f2, f, f2), True)

        elif f not in ma:

            act("remote created", "g", f, m2.flags(f))

        elif n != ma[f]:

            if repo.ui.promptchoice(

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

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

                (_("&Changed"), _("&Deleted")), 0) == 0:

                act("prompt recreating", "g", f, m2.flags(f))

    return action

def actionkey(a):

    return a[1] == 'r' and -1 or 0, a

def applyupdates(repo, action, wctx, mctx, actx):

    """apply the merge action list to the working directory

    wctx is the working copy context

    mctx is the context to be merged into the working copy

    actx is the context of the common ancestor

    """

    updated, merged, removed, unresolved = 0, 0, 0, 0

    ms = mergestate(repo)

    ms.reset(wctx.parents()[0].node())

    moves = []

    action.sort(key=actionkey)

    substate = wctx.substate # prime

    # prescan for merges

    u = repo.ui

    for a in action:

        f, m = a[:2]

        if m == 'm': # merge

            f2, fd, flags, move = a[2:]

            if f == '.hgsubstate': # merged internally

                continue

            repo.ui.debug("preserving %s for resolve of %s\n" % (f, fd))

            fcl = wctx[f]

            fco = mctx[f2]

            if mctx == actx: # backwards, use working dir parent as ancestor

                if fcl.parents():

                    fca = fcl.parents()[0]

                else:

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

            else:

                fca = fcl.ancestor(fco, actx)

            if not fca:

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

            ms.add(fcl, fco, fca, fd, flags)

            if f != fd and move:

                moves.append(f)

    # remove renamed files after safely stored

    for f in moves:

        if os.path.lexists(repo.wjoin(f)):

            repo.ui.debug("removing %s\n" % f)

            os.unlink(repo.wjoin(f))

    audit_path = util.path_auditor(repo.root)

    numupdates = len(action)

    for i, a in enumerate(action):

        f, m = a[:2]

        u.progress(_('updating'), i + 1, item=f, total=numupdates,

                   unit=_('files'))

        if f and f[0] == "/":

            continue

        if m == "r": # remove

            repo.ui.note(_("removing %s\n") % f)

            audit_path(f)

            if f == '.hgsubstate': # subrepo states need updating

                subrepo.submerge(repo, wctx, mctx, wctx)

            try:

                util.unlink(repo.wjoin(f))

            except OSError, inst:

                if inst.errno != errno.ENOENT:

                    repo.ui.warn(_("update failed to remove %s: %s!\n") %

                                 (f, inst.strerror))

            removed += 1

        elif m == "m": # merge

            if f == '.hgsubstate': # subrepo states need updating

                subrepo.submerge(repo, wctx, mctx, wctx.ancestor(mctx))

                continue

            f2, fd, flags, move = a[2:]

            r = ms.resolve(fd, wctx, mctx)

            if r is not None and r > 0:

                unresolved += 1

            else:

                if r is None:

                    updated += 1

                else:

                    merged += 1

            util.set_flags(repo.wjoin(fd), 'l' in flags, 'x' in flags)

            if f != fd and move and os.path.lexists(repo.wjoin(f)):

                repo.ui.debug("removing %s\n" % f)

                os.unlink(repo.wjoin(f))

        elif m == "g": # get

            flags = a[2]

            repo.ui.note(_("getting %s\n") % f)

            t = mctx.filectx(f).data()

            repo.wwrite(f, t, flags)

            t = None

            updated += 1

            if f == '.hgsubstate': # subrepo states need updating

                subrepo.submerge(repo, wctx, mctx, wctx)

        elif m == "d": # directory rename

            f2, fd, flags = a[2:]

            if f:

                repo.ui.note(_("moving %s to %s\n") % (f, fd))

                t = wctx.filectx(f).data()

                repo.wwrite(fd, t, flags)

                util.unlink(repo.wjoin(f))

            if f2:

                repo.ui.note(_("getting %s to %s\n") % (f2, fd))

                t = mctx.filectx(f2).data()

                repo.wwrite(fd, t, flags)

            updated += 1

        elif m == "dr": # divergent renames

            fl = a[2]

            repo.ui.warn(_("note: possible conflict - %s was renamed "

                           "multiple times to:\n") % f)

            for nf in fl:

                repo.ui.warn(" %s\n" % nf)

        elif m == "e": # exec

            flags = a[2]

            util.set_flags(repo.wjoin(f), 'l' in flags, 'x' in flags)

    ms.commit()

    u.progress(_('updating'), None, total=numupdates, unit=_('files'))

    return updated, merged, removed, unresolved

def recordupdates(repo, action, branchmerge):

    "record merge actions to the dirstate"

    for a in action:

        f, m = a[:2]

        if m == "r": # remove

            if branchmerge:

                repo.dirstate.remove(f)

            else:

                repo.dirstate.forget(f)

        elif m == "a": # re-add

            if not branchmerge:

                repo.dirstate.add(f)

        elif m == "f": # forget

            repo.dirstate.forget(f)

        elif m == "e": # exec change

            repo.dirstate.normallookup(f)

        elif m == "g": # get

            if branchmerge:

                repo.dirstate.otherparent(f)

            else:

                repo.dirstate.normal(f)

        elif m == "m": # merge

            f2, fd, flag, move = a[2:]

            if branchmerge:

                # We've done a branch merge, mark this file as merged

                # so that we properly record the merger later

                repo.dirstate.merge(fd)

                if f != f2: # copy/rename

                    if move:

                        repo.dirstate.remove(f)

                    if f != fd:

                        repo.dirstate.copy(f, fd)

                    else:

                        repo.dirstate.copy(f2, fd)

            else:

                # We've update-merged a locally modified file, so

                # we set the dirstate to emulate a normal checkout

                # of that file some time in the past. Thus our

                # merge will appear as a normal local file

                # modification.

                if f2 == fd: # file not locally copied/moved

                    repo.dirstate.normallookup(fd)

                if move:

                    repo.dirstate.forget(f)

        elif m == "d": # directory rename

            f2, fd, flag = a[2:]

            if not f2 and f not in repo.dirstate:

                # untracked file moved

                continue

            if branchmerge:

                repo.dirstate.add(fd)

                if f:

                    repo.dirstate.remove(f)

                    repo.dirstate.copy(f, fd)

                if f2:

                    repo.dirstate.copy(f2, fd)

            else:

                repo.dirstate.normal(fd)

                if f:

                    repo.dirstate.forget(f)

def update(repo, node, branchmerge, force, partial):

    """

    Perform a merge between the working directory and the given node

    node = the node to update to, or None if unspecified

    branchmerge = whether to merge between branches

    force = whether to force branch merging or file overwriting

    partial = a function to filter file lists (dirstate not updated)

    The table below shows all the behaviors of the update command

    given the -c and -C or no options, whether the working directory

    is dirty, whether a revision is specified, and the relationship of

    the parent rev to the target rev (linear, on the same named

    branch, or on another named branch).

    This logic is tested by test-update-branches.t.

    -c  -C  dirty  rev  |  linear   same  cross

     n   n    n     n   |    ok     (1)     x

     n   n    n     y   |    ok     ok     ok

     n   n    y     *   |   merge   (2)    (2)

     n   y    *     *   |    ---  discard  ---

     y   n    y     *   |    ---    (3)    ---

     y   n    n     *   |    ---    ok     ---

     y   y    *     *   |    ---    (4)    ---

    x = can't happen

    * = don't-care

    1 = abort: crosses branches (use 'hg merge' or 'hg update -c')

    2 = abort: crosses branches (use 'hg merge' to merge or

                 use 'hg update -C' to discard changes)

    3 = abort: uncommitted local changes

    4 = incompatible options (checked in commands.py)

    """

    onode = node

    wlock = repo.wlock()

    try:

        wc = repo[None]

        if node is None:

            # tip of current branch

            try:

                node = repo.branchtags()[wc.branch()]

            except KeyError:

                if wc.branch() == "default": # no default branch!

                    node = repo.lookup("tip") # update to tip

                else:

                    raise util.Abort(_("branch %s not found") % wc.branch())

        overwrite = force and not branchmerge

        pl = wc.parents()

        p1, p2 = pl[0], repo[node]

        pa = p1.ancestor(p2)

        fp1, fp2, xp1, xp2 = p1.node(), p2.node(), str(p1), str(p2)

        fastforward = False

        ### check phase

        if not overwrite and len(pl) > 1:

            raise util.Abort(_("outstanding uncommitted merges"))

        if branchmerge:

            if pa == p2:

                raise util.Abort(_("merging with a working directory ancestor"

                                   " has no effect"))

            elif pa == p1:

                if p1.branch() != p2.branch():

                    fastforward = True

                else:

                    raise util.Abort(_("nothing to merge (use 'hg update'"

                                       " or check 'hg heads')"))

            if not force and (wc.files() or wc.deleted()):

                raise util.Abort(_("outstanding uncommitted changes "

                                   "(use 'hg status' to list changes)"))

        elif not overwrite:

            if pa == p1 or pa == p2: # linear

                pass # all good

            elif wc.files() or wc.deleted():

                raise util.Abort(_("crosses branches (merge branches or use"

                                   " --clean to discard changes)"))

            elif onode is None:

                raise util.Abort(_("crosses branches (merge branches or use"

                                   " --check to force update)"))

            else:

                # Allow jumping branches if clean and specific rev given

                overwrite = True

        ### calculate phase

        action = []

        wc.status(unknown=True) # prime cache

        if not force:

            _checkunknown(wc, p2)

        if not util.checkcase(repo.path):

            _checkcollision(p2)

        action += _forgetremoved(wc, p2, branchmerge)

        action += manifestmerge(repo, wc, p2, pa, overwrite, partial)

        ### apply phase

        if not branchmerge: # just jump to the new rev

            fp1, fp2, xp1, xp2 = fp2, nullid, xp2, ''

        if not partial: