# filemerge.py - file-level merge handling for Mercurial

#

# Copyright 2006, 2007, 2008 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 _

import util, os, tempfile, context

def filemerge(repo, fw, fd, fo, wctx, mctx):

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

    fw = original filename in the working directory

    fd = destination filename in the working directory

    fo = filename in other parent

    wctx, mctx = working and merge changecontexts

    """

    def temp(prefix, ctx):

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

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

        data = repo.wwritedata(ctx.path(), ctx.data())

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

        f.write(data)

        f.close()

        return name

    fcm = wctx.filectx(fw)

    fcmdata = wctx.filectx(fd).data()

    fco = mctx.filectx(fo)

    if not fco.cmp(fcmdata): # files identical?

        return None

    fca = fcm.ancestor(fco)

    if not fca:

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

    a = repo.wjoin(fd)

    b = temp("base", fca)

    c = temp("other", fco)

    if fw != fo:

        repo.ui.status(_("merging %s and %s\n") % (fw, fo))

    else:

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

    repo.ui.debug(_("my %s other %s ancestor %s\n") % (fcm, fco, fca))

    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': fd,

                             'HG_MY_NODE': str(wctx.parents()[0]),

                             'HG_OTHER_NODE': str(mctx),

                             'HG_MY_ISLINK': fcm.islink(),

                             'HG_OTHER_ISLINK': fco.islink(),

                             'HG_BASE_ISLINK': fca.islink(),})

    if r:

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

    os.unlink(b)

    os.unlink(c)

    return r