# merge.py - directory-level update/merge handling for Mercurial

#

# Copyright 2006 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 gettext as _

from demandload import *

demandload(globals(), "errno util os tempfile")

def fmerge(f, local, other, ancestor):

    """merge executable flags"""

    a, b, c = ancestor.execf(f), local.execf(f), other.execf(f)

    return ((a^b) | (a^c)) ^ a

def merge3(repo, fn, my, other, p1, p2):

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

    def temp(prefix, node):

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

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

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

        repo.wwrite(fn, fl.read(node), f)

        f.close()

        return name

    fl = repo.file(fn)

    base = fl.ancestor(my, other)

    a = repo.wjoin(fn)

    b = temp("base", base)

    c = temp("other", other)

    repo.ui.note(_("resolving %s\n") % fn)

    repo.ui.debug(_("file %s: my %s other %s ancestor %s\n") %

                          (fn, short(my), short(other), short(base)))

    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': fn,

                             'HG_MY_NODE': p1,

                             'HG_OTHER_NODE': p2,

                             'HG_FILE_MY_NODE': hex(my),

                             'HG_FILE_OTHER_NODE': hex(other),

                             'HG_FILE_BASE_NODE': hex(base)})

    if r:

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

    os.unlink(b)

    os.unlink(c)

    return r

def update(repo, node, branchmerge=False, force=False, partial=None,

           wlock=None, show_stats=True, remind=True):

    overwrite = force and not branchmerge

    forcemerge = force and branchmerge

    if not wlock:

        wlock = repo.wlock()

    ### check phase

    pl = repo.dirstate.parents()

    if not overwrite and pl[1] != nullid:

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

    p1, p2 = pl[0], node

    pa = repo.changelog.ancestor(p1, p2)

    # are we going backwards?

    backwards = (pa == p2)

    # is there a linear path from p1 to p2?

    linear_path = (pa == p1 or pa == p2)

    if branchmerge and linear_path:

        raise util.Abort(_("there is nothing to merge, just use "

                           "'hg update' or look at 'hg heads'"))

    if not linear_path and not (overwrite or branchmerge):

        raise util.Abort(_("update spans branches, use 'hg merge' "

                           "or 'hg update -C' to lose changes"))

    modified, added, removed, deleted, unknown = repo.status()[:5]

    if branchmerge and not forcemerge:

        if modified or added or removed:

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

    m1 = repo.changectx(p1).manifest().copy()

    m2 = repo.changectx(p2).manifest().copy()

    ma = repo.changectx(pa).manifest()

    if not force:

        for f in unknown:

            if f in m2:

                if repo.file(f).cmp(m2[f], repo.wread(f)):

                    raise util.Abort(_("'%s' already exists in the working"

                                       " dir and differs from remote") % f)

    # resolve the manifest to determine which files

    # we care about merging

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

    repo.ui.debug(_(" overwrite %s branchmerge %s partial %s linear %s\n") %

                  (overwrite, branchmerge, bool(partial), linear_path))

    repo.ui.debug(_(" ancestor %s local %s remote %s\n") %

                  (short(p1), short(p2), short(pa)))

    action = []

    # update m1 from working dir

    umap = dict.fromkeys(unknown)

    for i,l in (("a", added), ("m", modified), ("u", unknown)):

        for f in l:

            m1[f] = m1.get(f, nullid) + i

            m1.set(f, util.is_exec(repo.wjoin(f), m1.execf(f)))

    for f in deleted + removed:

        del m1[f]

        # 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 linear_path and f not in m2:

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

    if partial:

        for f in m1.keys():

            if not partial(f): del m1[f]

        for f in m2.keys():

            if not partial(f): del m2[f]

    del m1, m2, ma

    ### apply phase

    if linear_path or overwrite:

        # we don't need to do any magic, just jump to the new rev

        p1, p2 = p2, nullid

    xp1 = hex(p1)

    xp2 = hex(p2)

    if p2 == nullid: xxp2 = ''

    else: xxp2 = xp2

    repo.hook('preupdate', throw=True, parent1=xp1, parent2=xxp2)

    # update files

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

    action.sort()

    for a in action:

        f, m = a[:2]

        if f[0] == "/":

            continue

        if m == "r": # remove

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

            util.audit_path(f)

            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

            flag, my, other = a[2:]

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

            if merge3(repo, f, my, other, xp1, xp2):

                unresolved += 1

            util.set_exec(repo.wjoin(f), flag)

            merged += 1

        elif m == "g": # get

            flag, node = a[2:]

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

            t = repo.file(f).read(node)

            repo.wwrite(f, t)

            util.set_exec(repo.wjoin(f), flag)

            updated += 1

        elif m == "e": # exec

            flag = a[2:]

            util.set_exec(repo.wjoin(f), flag)

    # update dirstate

    if not partial:

        repo.dirstate.setparents(p1, p2)

        for a in action:

            f, m = a[:2]

            if m == "r": # remove

                if branchmerge:

                    repo.dirstate.update([f], 'r')

                else:

                    repo.dirstate.forget([f])

            elif m == "f": # forget

                repo.dirstate.forget([f])

            elif m == "g": # get

                if branchmerge:

                    repo.dirstate.update([f], 'n', st_mtime=-1)

                else:

                    repo.dirstate.update([f], 'n')

            elif m == "m": # merge

                flag, my, other = 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.update([f], 'm')

                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.

                    fl = repo.file(f)

                    f_len = fl.size(fl.rev(other))

                    repo.dirstate.update([f], 'n', st_size=f_len, st_mtime=-1)

    if show_stats:

        stats = ((updated, _("updated")),

                 (merged - unresolved, _("merged")),

                 (removed, _("removed")),

                 (unresolved, _("unresolved")))

        note = ", ".join([_("%d files %s") % s for s in stats])

        repo.ui.status("%s\n" % note)

    if not partial:

        if branchmerge:

            if unresolved:

                repo.ui.status(_("There are unresolved merges,"

                                " you can redo the full merge using:\n"

                                "  hg update -C %s\n"

                                "  hg merge %s\n"

                                % (repo.changelog.rev(p1),

                                    repo.changelog.rev(p2))))

            elif remind:

                repo.ui.status(_("(branch merge, don't forget to commit)\n"))

        elif unresolved:

            repo.ui.status(_("There are unresolved merges with"

                             " locally modified files.\n"))

    repo.hook('update', parent1=xp1, parent2=xxp2, error=unresolved)

    return unresolved