def extract_mentioned_usernames(text):

    r"""

    Returns list of (possible) usernames @mentioned in given text.

    >>> extract_mentioned_usernames('@1-2.a_X,@1234 not@not @ddd@not @n @ee @ff @gg, @gg;@hh @n\n@zz,')

    ['1-2.a_X', '1234', 'ddd', 'ee', 'ff', 'gg', 'gg', 'hh', 'zz']

    """

    return MENTIONS_REGEX.findall(text)

def extract_mentioned_users(text):

    """ Returns set of actual database Users @mentioned in given text. """

    from kallithea.model.db import User

    result = set()

    for name in extract_mentioned_usernames(text):

        user = User.get_by_username(name, case_insensitive=True)

        if user is not None and not user.is_default_user:

            result.add(user)

    return result

class AttributeDict(dict):

    def __getattr__(self, attr):

        return self.get(attr, None)

    __setattr__ = dict.__setitem__

    __delattr__ = dict.__delitem__

def obfuscate_url_pw(engine):

    from sqlalchemy.engine import url as sa_url

    from sqlalchemy.exc import ArgumentError

    try:

        _url = sa_url.make_url(engine or '')

    except ArgumentError:

        return engine

    if _url.password:

        _url.password = 'XXXXX'

    return str(_url)

class HookEnvironmentError(Exception): pass

def get_hook_environment():

    """

    Get hook context by deserializing the global KALLITHEA_EXTRAS environment

    variable.

    Called early in Git out-of-process hooks to get .ini config path so the

    basic environment can be configured properly. Also used in all hooks to get

    information about the action that triggered it.

    """

    try:

        kallithea_extras = os.environ['KALLITHEA_EXTRAS']

    except KeyError:

        raise HookEnvironmentError("Environment variable KALLITHEA_EXTRAS not found")

    extras = json.loads(kallithea_extras)

    for k in ['username', 'repository', 'scm', 'action', 'ip', 'config']:

        try:

            extras[k]

        except KeyError:

            raise HookEnvironmentError('Missing key %s in KALLITHEA_EXTRAS %s' % (k, extras))

    return AttributeDict(extras)

def set_hook_environment(username, ip_addr, repo_name, repo_alias, action=None):

    """Prepare global context for running hooks by serializing data in the

    global KALLITHEA_EXTRAS environment variable.

    Most importantly, this allow Git hooks to do proper logging and updating of

    caches after pushes.

    Must always be called before anything with hooks are invoked.

    """

    from kallithea import CONFIG

    extras = {

        'ip': ip_addr, # used in log_push/pull_action action_logger

        'username': username,

        'action': action or 'push_local', # used in log_push_action_raw_ids action_logger

        'repository': repo_name,

        'scm': repo_alias, # used to pick hack in log_push_action_raw_ids

        'config': CONFIG['__file__'], # used by git hook to read config

    }

    os.environ['KALLITHEA_EXTRAS'] = json.dumps(extras)

def get_current_authuser():

    """

    Gets kallithea user from threadlocal tmpl_context variable if it's

    defined, else returns None.

    """

    from tg import tmpl_context

class OptionalAttr(object):

    """

    Special Optional Option that defines other attribute. Example::

        def test(apiuser, userid=Optional(OAttr('apiuser')):

            user = Optional.extract(userid)

            # calls

    """

    def __init__(self, attr_name):

        self.attr_name = attr_name

    def __repr__(self):

        return '<OptionalAttr:%s>' % self.attr_name

    def __call__(self):

        return self

# alias

OAttr = OptionalAttr

class Optional(object):

    """

    Defines an optional parameter::

        param = param.getval() if isinstance(param, Optional) else param

        param = param() if isinstance(param, Optional) else param

    is equivalent of::

        param = Optional.extract(param)

    """

    def __init__(self, type_):

        self.type_ = type_

    def __repr__(self):

        return '<Optional:%s>' % self.type_.__repr__()

    def __call__(self):

        return self.getval()

    def getval(self):

        """

        returns value from this Optional instance

        """

        if isinstance(self.type_, OAttr):

            # use params name

            return self.type_.attr_name

        return self.type_

    @classmethod

    def extract(cls, val):

        """

        Extracts value from Optional() instance

        :param val:

        :return: original value if it's not Optional instance else

            value of instance

        """

        if isinstance(val, cls):

            return val.getval()

        return val

def urlreadable(s, _cleanstringsub=re.compile('[^-a-zA-Z0-9./]+').sub):

    return _cleanstringsub('_', safe_str(s)).rstrip('_')

def recursive_replace(str_, replace=' '):

    """

    Recursive replace of given sign to just one instance

    :param str_: given string

    :param replace: char to find and replace multiple instances

    Examples::

    >>> recursive_replace("Mighty---Mighty-Bo--sstones",'-')

    'Mighty-Mighty-Bo-sstones'

    """

    if str_.find(replace * 2) == -1:

        return str_

    else:

        str_ = str_.replace(replace * 2, replace)

        return recursive_replace(str_, replace)

def repo_name_slug(value):

    """