# 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 __future__ import absolute_import

import contextlib

import os

import re

import shutil

import tempfile

from .i18n import _

from .node import nullid, short

from . import (

    encoding,

    error,

    formatter,

    match,

    pycompat,

    registrar,

    scmutil,

    simplemerge,

    tagmerge,

    templatekw,

    templater,

    util,

)

def _toolstr(ui, tool, part, *args):

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

def _toolbool(ui, tool, part,*args):

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

def _toollist(ui, tool, part):

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

internals = {}

# Merge tools to document.

internalsdoc = {}

internaltool = registrar.internalmerge()

# internal tool merge types

nomerge = internaltool.nomerge

mergeonly = internaltool.mergeonly # just the full merge, no premerge

fullmerge = internaltool.fullmerge # both premerge and merge

_localchangedotherdeletedmsg = _(

    "local%(l)s changed %(fd)s which other%(o)s deleted\n"

    "use (c)hanged version, (d)elete, or leave (u)nresolved?"

    "$$ &Changed $$ &Delete $$ &Unresolved")

_otherchangedlocaldeletedmsg = _(

    "other%(o)s changed %(fd)s which local%(l)s deleted\n"

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

    "leave (u)nresolved?"

    "$$ &Changed $$ &Deleted $$ &Unresolved")

class absentfilectx(object):

    """Represents a file that's ostensibly in a context but is actually not

    present in it.

    This is here because it's very specific to the filemerge code for now --

    other code is likely going to break with the values this returns."""

    def __init__(self, ctx, f):

        self._ctx = ctx

        self._f = f

    def path(self):

        return self._f

    def size(self):

        return None

    def data(self):

        return None

    def filenode(self):

        return nullid

    _customcmp = True

    def cmp(self, fctx):

        """compare with other file context

        returns True if different from fctx.

        """

        return not (fctx.isabsent() and

                    fctx.ctx() == self.ctx() and

                    fctx.path() == self.path())

    def flags(self):

        return ''

    def changectx(self):

        return self._ctx

    def isbinary(self):

        return False

    def isabsent(self):

        return True

def _findtool(ui, tool):

    if tool in internals:

        return tool

    return findexternaltool(ui, tool)

def findexternaltool(ui, 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, changedelete):

    def supportscd(tool):

        return tool in internals and internals[tool].mergetype == nomerge

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

        tmsg = tool

        if pat:

            tmsg = _("%s (for pattern %s)") % (tool, 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 changedelete and not supportscd(tool):

            # the nomerge tools are the only tools that support change/delete

            # conflicts

            pass

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

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

        else:

            return True

        return False

    # internal config: ui.forcemerge

    # forcemerge comes from command line arguments, highest priority

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

    if force:

        toolpath = _findtool(ui, force)

        if changedelete and not supportscd(toolpath):

            return ":prompt", None

        else:

            if toolpath:

                return (force, util.shellquote(toolpath))

            else:

                # mimic HGMERGE if given tool not found

                return (force, force)

    # HGMERGE takes next precedence

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

    if hgmerge:

        if changedelete and not supportscd(hgmerge):

            return ":prompt", None

        else:

            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, changedelete):

            toolpath = _findtool(ui, tool)

            return (tool, util.shellquote(toolpath))

    # then merge tools

    tools = {}

    disabled = set()

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

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

        if t not in tools:

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

        if _toolbool(ui, t, "disabled"):

            disabled.add(t)

    names = tools.keys()

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

                    if tool not in disabled])

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

    if uimerge:

        # external tools defined in uimerge won't be able to handle

        # change/delete conflicts

        if uimerge not in names and not changedelete:

            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, changedelete):

            toolpath = _findtool(ui, t)

            return (t, util.shellquote(toolpath))

    # internal merge or prompt as last resort

    if symlink or binary or changedelete:

        if not changedelete and len(tools):

            # any tool is rejected by capability for symlink or binary

            ui.warn(_("no tool found to merge %s\n") % path)

        return ":prompt", None

    return ":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, back):

    "Convert EOL markers in a file to match origfile"

    tostyle = _eoltype(back.data()) # No repo.wread filters?

    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', nomerge)

def _iprompt(repo, mynode, orig, fcd, fco, fca, toolconf, labels=None):

    """Asks the user which of the local `p1()` or the other `p2()` version to

    keep as the merged version."""

    ui = repo.ui

    fd = fcd.path()

    # Avoid prompting during an in-memory merge since it doesn't support merge

    # conflicts.

    if fcd.changectx().isinmemory():

        raise error.InMemoryMergeConflictsError('in-memory merge does not '

                                                'support file conflicts')

    prompts = partextras(labels)

    prompts['fd'] = fd

    try:

        if fco.isabsent():

            index = ui.promptchoice(

                _localchangedotherdeletedmsg % prompts, 2)

            choice = ['local', 'other', 'unresolved'][index]

        elif fcd.isabsent():

            index = ui.promptchoice(

                _otherchangedlocaldeletedmsg % prompts, 2)

            choice = ['other', 'local', 'unresolved'][index]

        else:

            index = ui.promptchoice(

                _("keep (l)ocal%(l)s, take (o)ther%(o)s, or leave (u)nresolved"

                  " for %(fd)s?"

                  "$$ &Local $$ &Other $$ &Unresolved") % prompts, 2)

            choice = ['local', 'other', 'unresolved'][index]

        if choice == 'other':

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

                           labels)

        elif choice == 'local':

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

                           labels)

        elif choice == 'unresolved':

            return _ifail(repo, mynode, orig, fcd, fco, fca, toolconf,

                          labels)

    except error.ResponseExpected:

        ui.write("\n")

        return _ifail(repo, mynode, orig, fcd, fco, fca, toolconf,

                      labels)

@internaltool('local', nomerge)

def _ilocal(repo, mynode, orig, fcd, fco, fca, toolconf, labels=None):

    """Uses the local `p1()` version of files as the merged version."""

    return 0, fcd.isabsent()

@internaltool('other', nomerge)

def _iother(repo, mynode, orig, fcd, fco, fca, toolconf, labels=None):

    """Uses the other `p2()` version of files as the merged version."""

    if fco.isabsent():

        # local changed, remote deleted -- 'deleted' picked

        _underlyingfctxifabsent(fcd).remove()

        deleted = True

    else:

        _underlyingfctxifabsent(fcd).write(fco.data(), fco.flags())

        deleted = False

    return 0, deleted

@internaltool('fail', nomerge)

def _ifail(repo, mynode, orig, fcd, fco, fca, toolconf, labels=None):

    """

    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."""

    # for change/delete conflicts write out the changed version, then fail

    if fcd.isabsent():

        _underlyingfctxifabsent(fcd).write(fco.data(), fco.flags())

    return 1, False

def _underlyingfctxifabsent(filectx):

    """Sometimes when resolving, our fcd is actually an absentfilectx, but

    we want to write to it (to do the resolve). This helper returns the

    underyling workingfilectx in that case.

    """

    if filectx.isabsent():

        return filectx.changectx()[filectx.path()]

    else:

        return filectx

def _premerge(repo, fcd, fco, fca, toolconf, files, labels=None):

    tool, toolpath, binary, symlink = toolconf

    if symlink or fcd.isabsent() or fco.isabsent():

        return 1

    unused, unused, unused, back = files

    ui = repo.ui

    validkeep = ['keep', 'keep-merge3']

    # do we attempt to simplemerge first?

    try:

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

    except error.ConfigError:

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

        if premerge not in validkeep:

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

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

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

                                    (tool, premerge, _valid))

    if premerge:

        if premerge == 'keep-merge3':

            if not labels:

                labels = _defaultconflictlabels

            if len(labels) < 3:

                labels.append('base')

        r = simplemerge.simplemerge(ui, fcd, fca, fco, quiet=True, label=labels)

        if not r:

            ui.debug(" premerge successful\n")

            return 0

        if premerge not in validkeep:

            # restore from backup and try again

            _restorebackup(fcd, back)

    return 1 # continue merging

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

    tool, toolpath, binary, symlink = toolconf

    if symlink:

        repo.ui.warn(_('warning: internal %s cannot merge symlinks '

                       'for %s\n') % (tool, fcd.path()))

        return False

    if fcd.isabsent() or fco.isabsent():

        repo.ui.warn(_('warning: internal %s cannot merge change/delete '

                       'conflict for %s\n') % (tool, fcd.path()))

        return False

    return True

def _merge(repo, mynode, orig, fcd, fco, fca, toolconf, files, labels, mode):

    """

    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. Markers will have two sections, one for each side

    of merge, unless mode equals 'union' which suppresses the markers."""

    ui = repo.ui

    r = simplemerge.simplemerge(ui, fcd, fca, fco, label=labels, mode=mode)

    return True, r, False

@internaltool('union', fullmerge,

              _("warning: conflicts while merging %s! "

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

              precheck=_mergecheck)

def _iunion(repo, mynode, orig, fcd, fco, fca, toolconf, files, labels=None):

    """

    Uses the internal non-interactive simple merge algorithm for merging

    files. It will use both left and right sides for conflict regions.

    No markers are inserted."""

    return _merge(repo, mynode, orig, fcd, fco, fca, toolconf,

                  files, labels, 'union')

@internaltool('merge', fullmerge,

              _("warning: conflicts while merging %s! "

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

              precheck=_mergecheck)

def _imerge(repo, mynode, orig, fcd, fco, fca, toolconf, files, labels=None):

    """

    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. Markers will have two sections, one for each side

    of merge."""

    return _merge(repo, mynode, orig, fcd, fco, fca, toolconf,

                  files, labels, 'merge')

@internaltool('merge3', fullmerge,

              _("warning: conflicts while merging %s! "

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

              precheck=_mergecheck)

def _imerge3(repo, mynode, orig, fcd, fco, fca, toolconf, files, labels=None):

    """

    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. Marker will have three sections, one from each

    side of the merge and one for the base content."""

    if not labels:

        labels = _defaultconflictlabels

    if len(labels) < 3:

        labels.append('base')

    return _imerge(repo, mynode, orig, fcd, fco, fca, toolconf, files, labels)

def _imergeauto(repo, mynode, orig, fcd, fco, fca, toolconf, files,

                labels=None, localorother=None):

    """

    Generic driver for _imergelocal and _imergeother

    """

    assert localorother is not None

    tool, toolpath, binary, symlink = toolconf

    r = simplemerge.simplemerge(repo.ui, fcd, fca, fco, label=labels,

                                localorother=localorother)

    return True, r

@internaltool('merge-local', mergeonly, precheck=_mergecheck)

def _imergelocal(*args, **kwargs):

    """

    Like :merge, but resolve all conflicts non-interactively in favor

    of the local `p1()` changes."""

    success, status = _imergeauto(localorother='local', *args, **kwargs)

    return success, status, False

@internaltool('merge-other', mergeonly, precheck=_mergecheck)

def _imergeother(*args, **kwargs):

    """

    Like :merge, but resolve all conflicts non-interactively in favor

    of the other `p2()` changes."""

    success, status = _imergeauto(localorother='other', *args, **kwargs)

    return success, status, False

@internaltool('tagmerge', mergeonly,

              _("automatic tag merging of %s failed! "

                "(use 'hg resolve --tool :merge' or another merge "

                "tool of your choice)\n"))

def _itagmerge(repo, mynode, orig, fcd, fco, fca, toolconf, files, labels=None):

    """

    Uses the internal tag merge algorithm (experimental).

    """

    success, status = tagmerge.merge(repo, fcd, fco, fca)

    return success, status, False

@internaltool('dump', fullmerge)

def _idump(repo, mynode, orig, fcd, fco, fca, toolconf, files, labels=None):

    """

    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``.

    This implies premerge. Therefore, files aren't dumped, if premerge

    runs successfully. Use :forcedump to forcibly write files out.

    """

    a = _workingpath(repo, fcd)

    fd = fcd.path()

    from . import context

    if isinstance(fcd, context.overlayworkingfilectx):

        raise error.InMemoryMergeConflictsError('in-memory merge does not '

                                                'support the :dump tool.')

    util.writefile(a + ".local", fcd.decodeddata())