# win32mbcs.py -- MBCS filename support for Mercurial on Windows

#

# Copyright (c) 2008 Shun-ichi Goto <shunichi.goto@gmail.com>

#

# Version: 0.1

# Author:  Shun-ichi Goto <shunichi.goto@gmail.com>

#

# This software may be used and distributed according to the terms

# of the GNU General Public License, incorporated herein by reference.

#

"""Allow to use shift_jis/big5 filenames on Windows.

There is a well known issue "0x5c problem" on Windows.  It is a

trouble on handling path name as raw encoded byte sequence of

problematic encodings like shift_jis or big5.  The primary intent

of this extension is to allow using such a encoding on Mercurial

without strange file operation error.

By enabling this extension, hook mechanism is activated and some

functions are altered.  Usually, this encoding is your local encoding

on your system by default. So you can get benefit simply by enabling

this extension.

The encoding for filename is same one for terminal by default.  You

can change the encoding by setting HGENCODING environment variable.

This extension is usefull for:

 * Japanese Windows user using shift_jis encoding.

 * Chinese Windows user using big5 encoding.

 * Users who want to use a repository created with such a encoding.

Note: Unix people does not need to use this extension.

"""

import os

from mercurial.i18n import _

from mercurial import util

__all__ = ['install', 'uninstall', 'reposetup']

# codec and alias names of sjis and big5 to be faked.

_problematic_encodings = util.frozenset([

        'big5', 'big5-tw', 'csbig5',

        'big5hkscs', 'big5-hkscs', 'hkscs',

        'cp932', '932', 'ms932', 'mskanji', 'ms-kanji',

        'shift_jis', 'csshiftjis', 'shiftjis', 'sjis', 's_jis',

        'shift_jis_2004', 'shiftjis2004', 'sjis_2004', 'sjis2004',

        'shift_jisx0213', 'shiftjisx0213', 'sjisx0213', 's_jisx0213',

        ])

# attribute name to store original function

_ORIGINAL = '_original'

_ui = None

def decode_with_check(arg):

    if isinstance(arg, tuple):

        return tuple(map(decode_with_check, arg))

    elif isinstance(arg, list):

        return map(decode_with_check, arg)

    elif isinstance(arg, str):

        uarg = arg.decode(util._encoding)

        if arg == uarg.encode(util._encoding):

            return uarg

        else:

            raise UnicodeError("Not local encoding")

    else:

        return arg

def encode_with_check(arg):

    if isinstance(arg, tuple):

        return tuple(map(encode_with_check, arg))

    elif isinstance(arg, list):

        return map(encode_with_check, arg)

    elif isinstance(arg, unicode):

        ret = arg.encode(util._encoding)

        return ret

    else:

        return arg

def wrap(func):

    def wrapped(*args):

        # check argument is unicode, then call original

        for arg in args:

            if isinstance(arg, unicode):

                return func(*args)

        # make decoded argument list into uargs

        try:

            args = decode_with_check(args)

        except UnicodeError, exc:

            # If not encoded with _local_fs_encoding, report it then

            # continue with calling original function.

            _ui.warn(_("WARNING: [win32mbcs] filename conversion fail for" +

                     " %s: '%s'\n") % (util._encoding, args))

            return func(*args)

        # call as unicode operation, then return with encoding

        return encode_with_check(func(*args))

    # fake is only for relevant environment.

    if hasattr(func, _ORIGINAL) or \

            util._encoding.lower() not in _problematic_encodings:

        return func

    else:

        f = wrapped

        f.__name__ = func.__name__

        setattr(f, _ORIGINAL, func)   # hold original to restore

        return f

def unwrap(func):

    return getattr(func, _ORIGINAL, func)

def install():

    # wrap some python functions and mercurial functions

    # to handle raw bytes on Windows.

    # NOTE: dirname and basename is safe because they use result

    # of os.path.split()

    global _ui

    if not _ui:

        from mercurial import ui

        _ui = ui.ui()

    os.path.join = wrap(os.path.join)

    os.path.split = wrap(os.path.split) 

    os.path.splitext = wrap(os.path.splitext)

    os.path.splitunc = wrap(os.path.splitunc)

    os.path.normpath = wrap(os.path.normpath)

    os.path.normcase = wrap(os.path.normcase)

    os.makedirs = wrap(os.makedirs)

    util.endswithsep = wrap(util.endswithsep)

    util.splitpath = wrap(util.splitpath)

def uninstall():

    # restore original functions.

    os.path.join = unwrap(os.path.join)

    os.path.split = unwrap(os.path.split) 

    os.path.splitext = unwrap(os.path.splitext)

    os.path.splitunc = unwrap(os.path.splitunc)

    os.path.normpath = unwrap(os.path.normpath)

    os.path.normcase = unwrap(os.path.normcase)

    os.makedirs = unwrap(os.makedirs)

    util.endswithsep = unwrap(util.endswithsep)

    util.splitpath = unwrap(util.splitpath)

def reposetup(ui, repo):

    # TODO: decide use of config section for this extension

    global _ui

    _ui = ui

    if not os.path.supports_unicode_filenames:

        ui.warn(_("[win32mbcs] cannot activate on this platform.\n"))

        return

    # install features of this extension

    install()

    ui.debug(_("[win32mbcs] activeted with encoding: %s\n") % util._encoding)

# win32mbcs.py ends here