# 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 or any later version.

from node import short

from i18n import _

import util, simplemerge, match, error

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 _toollist(ui, tool, part, default=[]):

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

internals = {}

def internaltool(name, trymerge, onfailure=None):

    '''return a decorator for populating internal merge tool table'''

    def decorator(func):

        fullname = 'internal:' + name

        func.__doc__ = "``%s``\n" % fullname + func.__doc__.strip()

        internals[fullname] = func

        func.trymerge = trymerge

        func.onfailure = onfailure

        return func

    return decorator

def _findtool(ui, tool):

    if tool in internals:

        return tool

    for kn in ("regkey", "regkeyalt"):

        k = _toolstr(ui, tool, kn)

        if not k:

            continue

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

        if p:

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

            if p:

                return p

    exe = _toolstr(ui, tool, "executable", tool)

    return util.findexe(util.expandpath(exe))

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

    # forcemerge comes from command line arguments, highest priority

    force = ui.config('ui', 'forcemerge')

    if force:

        toolpath = _findtool(ui, force)

        if toolpath:

            return (force, util.shellquote(toolpath))

        else:

            # mimic HGMERGE if given tool not found

            return (force, force)

    # HGMERGE takes next precedence

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

    if hgmerge:

        return (hgmerge, hgmerge)

    # then patterns

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

        mf = match.match(repo.root, '', [pat])

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

            toolpath = _findtool(ui, tool)

            return (tool, util.shellquote(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, util.shellquote(toolpath))

    # internal merge or prompt as last resort

    if symlink or binary:

        return "internal:prompt", None

    return "internal:merge", 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(util.readfile(origfile))

    if tostyle:

        data = util.readfile(file)

        style = _eoltype(data)

        if style:

            newdata = data.replace(style, tostyle)

            if newdata != data:

                util.writefile(file, newdata)

@internaltool('prompt', False)

def _iprompt(repo, mynode, orig, fcd, fco, fca, toolconf):

    """Asks the user which of the local or the other version to keep as

    the merged version."""

    ui = repo.ui

    fd = fcd.path()

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

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

                       (_("&Local"), _("&Other")), 0):

        return _iother(repo, mynode, orig, fcd, fco, fca, toolconf)

    else:

        return _ilocal(repo, mynode, orig, fcd, fco, fca, toolconf)

@internaltool('local', False)

def _ilocal(repo, mynode, orig, fcd, fco, fca, toolconf):

    """Uses the local version of files as the merged version."""

    return 0

@internaltool('other', False)

def _iother(repo, mynode, orig, fcd, fco, fca, toolconf):

    """Uses the other version of files as the merged version."""

    repo.wwrite(fcd.path(), fco.data(), fco.flags())

    return 0

@internaltool('fail', False)

def _ifail(repo, mynode, orig, fcd, fco, fca, toolconf):

    """

    Rather than attempting to merge files that were modified on both

    branches, it marks them as unresolved. The resolve command must be

    used to resolve these conflicts."""

    return 1

def _premerge(repo, toolconf, files):

    tool, toolpath, binary, symlink = toolconf

    a, b, c, back = files

    ui = repo.ui

    # do we attempt to simplemerge first?

    try:

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

    except error.ConfigError:

        premerge = _toolstr(ui, tool, "premerge").lower()

        valid = 'keep'.split()

        if premerge not in valid:

            _valid = ', '.join(["'" + v + "'" for v in valid])

            raise error.ConfigError(_("%s.premerge not valid "

                                      "('%s' is neither boolean nor %s)") %

                                    (tool, premerge, _valid))

    if premerge:

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

        if not r:

            ui.debug(" premerge successful\n")

            return 0

        if premerge != 'keep':

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

    return 1 # continue merging

@internaltool('merge', True,

              _("merging %s incomplete! "

                "(edit conflicts, then use 'hg resolve --mark')\n"))

def _imerge(repo, mynode, orig, fcd, fco, fca, toolconf, files):

    """

    Uses the internal non-interactive simple merge algorithm for merging

    files. It will fail if there are any conflicts and leave markers in

    the partially merged file."""

    r = _premerge(repo, toolconf, files)

    if r:

        a, b, c, back = files

        ui = repo.ui

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

        return True, r

    return False, 0

@internaltool('dump', True)

def _idump(repo, mynode, orig, fcd, fco, fca, toolconf, files):

    """

    Creates three versions of the files to merge, containing the

    contents of local, other and base. These files can then be used to

    perform a merge manually. If the file to be merged is named

    ``a.txt``, these files will accordingly be named ``a.txt.local``,

    ``a.txt.other`` and ``a.txt.base`` and they will be placed in the

    same directory as ``a.txt``."""

    r = _premerge(repo, toolconf, files)

    if r:

        a, b, c, back = files

        fd = fcd.path()

        util.copyfile(a, a + ".local")

        repo.wwrite(fd + ".other", fco.data(), fco.flags())

        repo.wwrite(fd + ".base", fca.data(), fca.flags())

    return False, r

def _xmerge(repo, mynode, orig, fcd, fco, fca, toolconf, files):

    r = _premerge(repo, toolconf, files)

    if r:

        tool, toolpath, binary, symlink = toolconf

        a, b, c, back = files

        out = ""

        env = dict(HG_FILE=fcd.path(),

                   HG_MY_NODE=short(mynode),

                   HG_OTHER_NODE=str(fco.changectx()),

                   HG_BASE_NODE=str(fca.changectx()),

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

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

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

        ui = repo.ui

        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 = util.interpolate(r'\$', replace, args,

                                lambda s: util.shellquote(util.localpath(s)))

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

                        out=ui.fout)

        return True, r

    return False, 0

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

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

        return None

    ui = repo.ui

    fd = fcd.path()

    binary = fcd.isbinary() or fco.isbinary() or fca.isbinary()

    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 tool in internals:

        func = internals[tool]

        trymerge = func.trymerge

        onfailure = func.onfailure

    else:

        func = _xmerge

        trymerge = True

        onfailure = _("merging %s failed!\n")

    toolconf = tool, toolpath, binary, symlink

    if not trymerge:

        return func(repo, mynode, orig, fcd, fco, fca, toolconf)

    a = repo.wjoin(fd)

    b = temp("base", fca)

    c = temp("other", fco)

    back = a + ".orig"

    util.copyfile(a, back)

    if orig != fco.path():

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

    else:

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

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

    needcheck, r = func(repo, mynode, orig, fcd, fco, fca, toolconf,

                        (a, b, c, back))

    if not needcheck:

        if r:

            if onfailure:

                ui.warn(onfailure % fd)

        else:

            os.unlink(back)

        os.unlink(b)

        os.unlink(c)

        return r

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

                  'conflicts' in _toollist(ui, tool, "check")):

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

                     re.MULTILINE):

            r = 1

    checked = False

    if 'prompt' in _toollist(ui, tool, "check"):

        checked = True

        if ui.promptchoice(_("was merge of '%s' successful (yn)?") % fd,

                           (_("&Yes"), _("&No")), 1):

            r = 1

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

                                  'changed' in _toollist(ui, tool, "check")):

        if filecmp.cmp(a, back):

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

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