# 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 version 2, incorporated herein by reference.

from node import short

from i18n import _

import util, simplemerge

import os, tempfile, re, filecmp

def _toolstr(ui, tool, part, default=""):

    return ui.config("merge-tools", tool + "." + part, default)

def _toolbool(ui, tool, part, default=False):

    return ui.configbool("merge-tools", tool + "." + part, default)

def _findtool(ui, tool):

    if tool in ("internal:fail", "internal:local", "internal:other"):

        return tool

    k = _toolstr(ui, tool, "regkey")

    if k:

        p = util.lookup_reg(k, _toolstr(ui, tool, "regname"))

        if p:

            p = util.find_exe(p + _toolstr(ui, tool, "regappend"))

            if p:

                return p

    return util.find_exe(_toolstr(ui, tool, "executable", tool))

def _picktool(repo, ui, path, binary, symlink):

    def check(tool, pat, symlink, binary):

        tmsg = tool

        if pat:

            tmsg += " specified for " + pat

        if not _findtool(ui, tool):

            if pat: # explicitly requested tool deserves a warning

                ui.warn(_("couldn't find merge tool %s\n") % tmsg)

            else: # configured but non-existing tools are more silent

                ui.note(_("couldn't find merge tool %s\n") % tmsg)

        elif symlink and not _toolbool(ui, tool, "symlink"):

            ui.warn(_("tool %s can't handle symlinks\n") % tmsg)

        elif binary and not _toolbool(ui, tool, "binary"):

            ui.warn(_("tool %s can't handle binary\n") % tmsg)

        elif not util.gui() and _toolbool(ui, tool, "gui"):

            ui.warn(_("tool %s requires a GUI\n") % tmsg)

        else:

            return True

        return False

    # HGMERGE takes precedence

    hgmerge = os.environ.get("HGMERGE")

    if hgmerge:

        return (hgmerge, hgmerge)

    # then patterns

    for pat, tool in ui.configitems("merge-patterns"):

        mf = util.matcher(repo.root, "", [pat], [], [])[1]

        if mf(path) and check(tool, pat, symlink, False):

                toolpath = _findtool(ui, tool)

                return (tool, '"' + toolpath + '"')

    # then merge tools

    tools = {}

    for k,v in ui.configitems("merge-tools"):

        t = k.split('.')[0]

        if t not in tools:

            tools[t] = int(_toolstr(ui, t, "priority", "0"))

    names = tools.keys()

    tools = sorted([(-p,t) for t,p in tools.items()])

    uimerge = ui.config("ui", "merge")

    if uimerge:

        if uimerge not in names:

            return (uimerge, uimerge)

        tools.insert(0, (None, uimerge)) # highest priority

    tools.append((None, "hgmerge")) # the old default, if found

    for p,t in tools:

        if check(t, None, symlink, binary):

            toolpath = _findtool(ui, t)

            return (t, '"' + toolpath + '"')

    # internal merge as last resort

    return (not (symlink or binary) and "internal:merge" or None, None)

def _eoltype(data):

    "Guess the EOL type of a file"

    if '\0' in data: # binary

        return None

    if '\r\n' in data: # Windows

        return '\r\n'

    if '\r' in data: # Old Mac

        return '\r'

    if '\n' in data: # UNIX

        return '\n'

    return None # unknown

def _matcheol(file, origfile):

    "Convert EOL markers in a file to match origfile"

    tostyle = _eoltype(open(origfile, "rb").read())

    if tostyle:

        data = open(file, "rb").read()

        style = _eoltype(data)

        if style:

            newdata = data.replace(style, tostyle)

            if newdata != data:

                open(file, "wb").write(newdata)

def filemerge(repo, mynode, orig, fcd, fco, fca):

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

    mynode = parent node before merge

    orig = original local filename before merge

    fco = other file context

    fca = ancestor file context

    fcd = local file context for current/destination file

    """

    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

    def isbin(ctx):

        try:

            return util.binary(ctx.data())

        except IOError:

            return False

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

        return None

    ui = repo.ui

    fd = fcd.path()

    binary = isbin(fcd) or isbin(fco) or isbin(fca)

    symlink = 'l' in fcd.flags() + fco.flags()

    tool, toolpath = _picktool(repo, ui, fd, binary, symlink)

    ui.debug(_("picked tool '%s' for %s (binary %s symlink %s)\n") %

               (tool, fd, binary, symlink))

    if not tool:

        tool = "internal:local"

        if ui.prompt(_(" no tool found to merge %s\n"

                       "keep (l)ocal or take (o)ther?") % fd,

                     (_("&Local"), _("&Other")), _("l")) != _("l"):

            tool = "internal:other"

    if tool == "internal:local":

        return 0

    if tool == "internal:other":

        repo.wwrite(fd, fco.data(), fco.flags())

        return 0

    if tool == "internal:fail":

        return 1

    # do the actual merge

    a = repo.wjoin(fd)

    b = temp("base", fca)

    c = temp("other", fco)

    out = ""

    back = a + ".orig"

    util.copyfile(a, back)

    if orig != fco.path():

        repo.ui.status(_("merging %s and %s to %s\n") % (orig, fco.path(), fd))

    else:

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

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

    # do we attempt to simplemerge first?

    if _toolbool(ui, tool, "premerge", not (binary or symlink)):

        r = simplemerge.simplemerge(ui, a, b, c, quiet=True)

        if not r:

            ui.debug(_(" premerge successful\n"))

            os.unlink(back)

            os.unlink(b)

            os.unlink(c)

            return 0

        util.copyfile(back, a) # restore from backup and try again

    env = dict(HG_FILE=fd,

               HG_MY_NODE=short(mynode),

               HG_OTHER_NODE=str(fco.changectx()),

               HG_MY_ISLINK='l' in fcd.flags(),

               HG_OTHER_ISLINK='l' in fco.flags(),

               HG_BASE_ISLINK='l' in fca.flags())

    if tool == "internal:merge":

        r = simplemerge.simplemerge(ui, a, b, c, label=['local', 'other'])

    else:

        args = _toolstr(ui, tool, "args", '$local $base $other')

        if "$output" in args:

            out, a = a, back # read input from backup, write to original

        replace = dict(local=a, base=b, other=c, output=out)

        args = re.sub("\$(local|base|other|output)",

                      lambda x: '"%s"' % replace[x.group()[1:]], args)

        r = util.system(toolpath + ' ' + args, cwd=repo.root, environ=env)

    if not r and _toolbool(ui, tool, "checkconflicts"):

        if re.match("^(<<<<<<< .*|=======|>>>>>>> .*)$", fcd.data()):

            r = 1

    if not r and _toolbool(ui, tool, "checkchanged"):

        if filecmp.cmp(repo.wjoin(fd), back):

            if ui.prompt(_(" output file %s appears unchanged\n"

                "was merge successful (yn)?") % fd,

                (_("&Yes"), _("&No")), _("n")) != _("y"):

                r = 1

    if _toolbool(ui, tool, "fixeol"):

        _matcheol(repo.wjoin(fd), back)

    if r:

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

    else:

        os.unlink(back)

    os.unlink(b)

    os.unlink(c)

    return r