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

#

# Copyright 2006, 2007, 2008 Olivia Mackall <olivia@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.

import contextlib

import os

import re

import shutil

from .i18n import _

from .node import (

    hex,

    short,

)

from .pycompat import (

    getattr,

)

from . import (

    encoding,

    error,

    formatter,

    match,

    pycompat,

    registrar,

    scmutil,

    simplemerge,

    tagmerge,

    templatekw,

    templater,

    templateutil,

    util,

)

from .utils import (

    procutil,

    stringutil,

)

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

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

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

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

def _toollist(ui, tool, part):

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

# IMPORTANT: keep the last line of this prompt very short ("What do you want to

# do?") because of issue6158, ideally to <40 English characters (to allow other

# languages that may take more columns to still have a chance to fit in an

# 80-column screen).

_localchangedotherdeletedmsg = _(

    b"file '%(fd)s' was deleted in other%(o)s but was modified in local%(l)s.\n"

    b"You can use (c)hanged version, (d)elete, or leave (u)nresolved.\n"

    b"What do you want to do?"

    b"$$ &Changed $$ &Delete $$ &Unresolved"

)

_otherchangedlocaldeletedmsg = _(

    b"file '%(fd)s' was deleted in local%(l)s but was modified in other%(o)s.\n"

    b"You can use (c)hanged version, leave (d)eleted, or leave (u)nresolved.\n"

    b"What do you want to do?"

    b"$$ &Changed $$ &Deleted $$ &Unresolved"

)

class absentfilectx:

    """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 __bytes__(self):

        return b'absent file %s@%s' % (self._f, self._ctx)

    def path(self):

        return self._f

    def size(self):

        return None

    def data(self):

        return None

    def filenode(self):

        return self._ctx.repo().nullid

    _customcmp = True

    def cmp(self, fctx):

        """compare with other file context

        returns True if different from fctx.

        """

        return not (

            fctx.isabsent()

            and fctx.changectx() == self.changectx()

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

        )

    def flags(self):

        return b''

    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

    cmd = _toolstr(ui, tool, b"executable", tool)

    if cmd.startswith(b'python:'):

        return cmd

    return findexternaltool(ui, tool)

def _quotetoolpath(cmd):

    if cmd.startswith(b'python:'):

        return cmd

    return procutil.shellquote(cmd)

def findexternaltool(ui, tool):

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

        k = _toolstr(ui, tool, kn)

        if not k:

            continue

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

        if p:

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

            if p:

                return p

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

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

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

    strictcheck = ui.configbool(b'merge', b'strict-capability-check')

    def hascapability(tool, capability, strict=False):

        if tool in internals:

            return strict and internals[tool].capabilities.get(capability)

        return _toolbool(ui, tool, capability)

    def supportscd(tool):

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

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

        tmsg = tool

        if pat:

            tmsg = _(b"%s (for pattern %s)") % (tool, pat)

        if not _findtool(ui, tool):

            if pat:  # explicitly requested tool deserves a warning

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

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

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

        elif symlink and not hascapability(tool, b"symlink", strictcheck):

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

        elif binary and not hascapability(tool, b"binary", strictcheck):

            ui.warn(_(b"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 procutil.gui() and _toolbool(ui, tool, b"gui"):

            ui.warn(_(b"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(b'ui', b'forcemerge')

    if force:

        toolpath = _findtool(ui, force)

        if changedelete and not supportscd(toolpath):

            return b":prompt", None

        else:

            if toolpath:

                return (force, _quotetoolpath(toolpath))

            else:

                # mimic HGMERGE if given tool not found

                return (force, force)

    # HGMERGE takes next precedence

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

    if hgmerge:

        if changedelete and not supportscd(hgmerge):

            return b":prompt", None

        else:

            return (hgmerge, hgmerge)

    # then patterns

    # whether binary capability should be checked strictly

    binarycap = binary and strictcheck

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

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

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

            if binary and not hascapability(tool, b"binary", strict=True):

                ui.warn(

                    _(

                        b"warning: check merge-patterns configurations,"

                        b" if %r for binary file %r is unintentional\n"

                        b"(see 'hg help merge-tools'"

                        b" for binary files capability)\n"

                    )

                    % (pycompat.bytestr(tool), pycompat.bytestr(path))

                )

            toolpath = _findtool(ui, tool)

            return (tool, _quotetoolpath(toolpath))

    # then merge tools

    tools = {}

    disabled = set()

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

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

        if t not in tools:

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

        if _toolbool(ui, t, b"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(b"ui", b"merge")

    if uimerge:

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

        # change/delete conflicts

        if check(uimerge, path, symlink, binary, changedelete):

            if uimerge not in names and not changedelete:

                return (uimerge, uimerge)

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

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

    for p, t in tools:

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

            toolpath = _findtool(ui, t)

            return (t, _quotetoolpath(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(_(b"no tool found to merge %s\n") % path)

        return b":prompt", None

    return b":merge", None

def _eoltype(data):

    """Guess the EOL type of a file"""

    if b'\0' in data:  # binary

        return None

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

        return b'\r\n'

    if b'\r' in data:  # Old Mac

        return b'\r'

    if b'\n' in data:  # UNIX

        return b'\n'

    return None  # unknown

def _matcheol(file, backup):

    """Convert EOL markers in a file to match origfile"""

    tostyle = _eoltype(backup.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(b'prompt', nomerge)

def _iprompt(repo, mynode, local, other, base, toolconf):

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

    keep as the merged version."""

    ui = repo.ui

    fd = local.fctx.path()

    uipathfn = scmutil.getuipathfn(repo)

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

    # conflicts.

    if local.fctx.changectx().isinmemory():

        raise error.InMemoryMergeConflictsError(

            b'in-memory merge does not support file conflicts'

        )

    prompts = partextras([local.label, other.label])

    prompts[b'fd'] = uipathfn(fd)

    try:

        if other.fctx.isabsent():

            index = ui.promptchoice(_localchangedotherdeletedmsg % prompts, 2)

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

        elif local.fctx.isabsent():

            index = ui.promptchoice(_otherchangedlocaldeletedmsg % prompts, 2)

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

        else:

            # IMPORTANT: keep the last line of this prompt ("What do you want to

            # do?") very short, see comment next to _localchangedotherdeletedmsg

            # at the top of the file for details.

            index = ui.promptchoice(

                _(

                    b"file '%(fd)s' needs to be resolved.\n"

                    b"You can keep (l)ocal%(l)s, take (o)ther%(o)s, or leave "

                    b"(u)nresolved.\n"

                    b"What do you want to do?"

                    b"$$ &Local $$ &Other $$ &Unresolved"

                )

                % prompts,

                2,

            )

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

        if choice == b'other':

            return _iother(repo, mynode, local, other, base, toolconf)

        elif choice == b'local':

            return _ilocal(repo, mynode, local, other, base, toolconf)

        elif choice == b'unresolved':

            return _ifail(repo, mynode, local, other, base, toolconf)

    except error.ResponseExpected:

        ui.write(b"\n")

        return _ifail(repo, mynode, local, other, base, toolconf)

@internaltool(b'local', nomerge)

def _ilocal(repo, mynode, local, other, base, toolconf):

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

    return 0, local.fctx.isabsent()

@internaltool(b'other', nomerge)

def _iother(repo, mynode, local, other, base, toolconf):

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

    if other.fctx.isabsent():

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

        _underlyingfctxifabsent(local.fctx).remove()