# win32mbcs.py -- MBCS filename support for Mercurial

#

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

#

# Version: 0.2

# 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 MBCS path with problematic encoding.

Some MBCS encodings are not good for some path operations

(i.e. splitting path, case conversion, etc.) with its encoded bytes.

We call such a encoding (i.e. shift_jis and big5) as "problematic

encoding".  This extension can be used to fix the issue with those

encodings by wrapping some functions to convert to unicode string

before path operation.

This extension is usefull for:

 * Japanese Windows users using shift_jis encoding.

 * Chinese Windows users using big5 encoding.

 * All users who use a repository with one of problematic encodings

   on case-insensitive file system.

This extension is not needed for:

 * Any user who use only ascii chars in path.

 * Any user who do not use any of problematic encodings.

Note that there are some limitations on using this extension:

 * You should use single encoding in one repository.

 * You should set same encoding for the repository by locale or HGENCODING.

To use this extension, enable the extension in .hg/hgrc or ~/.hgrc:

  [extensions]

  hgext.win32mbcs =

Path encoding conversion are done between unicode and util._encoding

which is decided by mercurial from current locale setting or HGENCODING.

"""

import os

from mercurial.i18n import _

from mercurial import util

def decode(arg):

   if isinstance(arg, str):

       uarg = arg.decode(util._encoding)

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

           return uarg

       raise UnicodeError("Not local encoding")

   elif isinstance(arg, tuple):

       return tuple(map(decode, arg))

   elif isinstance(arg, list):

       return map(decode, arg)

   return arg

def encode(arg):

   if isinstance(arg, unicode):

       return arg.encode(util._encoding)

   elif isinstance(arg, tuple):

       return tuple(map(encode, arg))

   elif isinstance(arg, list):

       return map(encode, arg)

   return arg

def wrapper(func, args):

   # check argument is unicode, then call original

   for arg in args:

       if isinstance(arg, unicode):

           return func(*args)

   try:

       # convert arguments to unicode, call func, then convert back

       return encode(func(*decode(args)))

   except UnicodeError:

       # If not encoded with util._encoding, report it then

       # continue with calling original function.

      raise util.Abort(_("[win32mbcs] filename conversion fail with"

                         " %s encoding\n") % (util._encoding))

def wrapname(name):

   idx = name.rfind('.')

   module = name[:idx]

   name = name[idx+1:]

   module = eval(module)

   func = getattr(module, name)

   def f(*args):

       return wrapper(func, args)

   try:

      f.__name__ = func.__name__                # fail with python23

   except Exception:

      pass

   setattr(module, name, f)

# List of functions to be wrapped.

# NOTE: os.path.dirname() and os.path.basename() are safe because

#       they use result of os.path.split()

funcs = '''os.path.join os.path.split os.path.splitext

 os.path.splitunc os.path.normpath os.path.normcase os.makedirs

 util.endswithsep util.splitpath util.checkcase util.fspath'''

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

problematic_encodings = '''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'''

def reposetup(ui, repo):

   # TODO: decide use of config section for this extension

   if not os.path.supports_unicode_filenames:

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

       return

   # fake is only for relevant environment.

   if util._encoding.lower() in problematic_encodings.split():

       for f in funcs.split():

           wrapname(f)

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