client/cros/factory/unicode_to_string.py

#!/usr/bin/python -u
#
# Copyright (c) 2012 The Chromium OS Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

'''Wrappers to convert Unicode strings to UTF-8 strings.'''

import types


def UnicodeToString(obj):
    '''Converts any Unicode strings in obj to UTF-8 strings.

    Recurses into lists, dicts, and tuples in obj.
    '''
    if isinstance(obj, list):
        return [UnicodeToString(x) for x in obj]
    elif isinstance(obj, dict):
        return dict((UnicodeToString(k), UnicodeToString(v))
                    for k, v in obj.iteritems())
    elif isinstance(obj, unicode):
        return obj.encode('utf-8')
    elif isinstance(obj, tuple):
        return tuple(UnicodeToString(x) for x in obj)
    elif isinstance(obj, set):
        return set(UnicodeToString(x) for x in obj)
    else:
        return obj


def UnicodeToStringArgs(function):
    '''A function decorator that converts function's arguments from
    Unicode to strings using UnicodeToString.
    '''
    return (lambda *args, **kwargs:
                function(*UnicodeToString(args),
                          **UnicodeToString(kwargs)))


def UnicodeToStringClass(cls):
    '''A class decorator that converts all arguments of all
    methods in class from Unicode to strings using UnicodeToStringArgs.'''
    for k, v in cls.__dict__.items():
        if type(v) == types.FunctionType:
            setattr(cls, k, UnicodeToStringArgs(v))
    return cls