tiramisu/tiramisu/value.py

# -*- coding: utf-8 -*-
"takes care of the option's values and multi values"
# Copyright (C) 2013-2017 Team tiramisu (see AUTHORS for all contributors)
#
# This program is free software: you can redistribute it and/or modify it
# under the terms of the GNU Lesser General Public License as published by the
# Free Software Foundation, either version 3 of the License, or (at your
# option) any later version.
#
# This program is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
# FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more
# details.
#
# You should have received a copy of the GNU Lesser General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.
# ____________________________________________________________
from time import time
import sys
import weakref
from .error import ConfigError, SlaveError, PropertiesOptionError
from .setting import owners, expires_time, undefined
from .autolib import carry_out_calculation
from .i18n import _
from .option import DynSymLinkOption, Option


class Values(object):
    """The `Config`'s root is indeed  in charge of the `Option()`'s values,
    but the values are physicaly located here, in `Values`, wich is also
    responsible of a caching utility.
    """
    __slots__ = ('context', '_p_', '__weakref__')

    def __init__(self, context, storage):
        """
        Initializes the values's dict.

        :param context: the context is the home config's values

        """
        self.context = weakref.ref(context)
        # the storage type is dictionary or sqlite3
        self._p_ = storage

    def _getcontext(self):
        """context could be None, we need to test it
        context is None only if all reference to `Config` object is deleted
        (for example we delete a `Config` and we manipulate a reference to
        old `SubConfig`, `Values`, `Multi` or `Settings`)
        """
        context = self.context()
        if context is None:
            raise ConfigError(_('the context does not exist anymore'))
        return context

    def _get_multi(self, opt, path):
        return Multi([], self.context, opt, path)

    def _getdefaultvalue(self, opt, path, with_meta, index, submulti_index, validate,
                         _orig_context=undefined):
        if _orig_context is undefined:
            _orig_context = self._getcontext()
        if with_meta:
            meta = self._getcontext().cfgimpl_get_meta()
            if meta is not None:
                value = meta.cfgimpl_get_values(
                )._get_cached_value(opt, path, index=index, submulti_index=submulti_index,
                                    from_masterslave=True, _orig_context=_orig_context)
                if isinstance(value, Exception):
                    if not isinstance(value, PropertiesOptionError):  # pragma: no cover
                        raise value
                else:
                    if isinstance(value, Multi):
                        new_value = []
                        for val in value:
                            if isinstance(val, SubMulti):
                                val = list(val)
                            new_value.append(val)
                        value = new_value
                        del new_value
                    return value
        # if value has callback and is not set
        if opt.impl_has_callback():
            callback, callback_params = opt.impl_get_callback()
            value = carry_out_calculation(opt, context=_orig_context,
                                          callback=callback,
                                          callback_params=callback_params,
                                          index=index, validate=validate)
            _orig_context.cfgimpl_reset_cache(opt=opt, path=path, only=('values',))
            if isinstance(value, list) and index is not None:
                #if return a list and index is set, return value only if
                #it's a submulti without submulti_index and without list of list
                if opt.impl_is_submulti() and submulti_index is undefined and \
                        (len(value) == 0 or not isinstance(value[0], list)):
                    return value
                if not opt.impl_is_submulti() and len(value) > index:
                    return value[index]
            else:
                return value
        # now try to get default value
        value = opt.impl_getdefault()
        if opt.impl_is_multi() and index is not None:
            if value == []:
                value = opt.impl_getdefault_multi()
            else:
                if len(value) > index:
                    value = value[index]
                else:
                    value = opt.impl_getdefault_multi()
        return value

    def _getvalue(self, opt, path, self_properties, index, submulti_index,
                  with_meta, masterlen, session, validate, _orig_context):
        """actually retrieves the value

        :param opt: the `option.Option()` object
        :returns: the option's value (or the default value if not set)
        """
        force_default = 'frozen' in self_properties and \
            'force_default_on_freeze' in self_properties
        # not default value
        if index is None or not opt.impl_is_master_slaves('slave'):
            _index = None
        else:
            _index = index
        owner, value = self._p_.getowner(path, owners.default, session, only_default=True,
                                           index=_index, with_value=True)
        is_default = owner == owners.default
        if not is_default and not force_default:
            if index is not None and not opt.impl_is_master_slaves('slave'):
                if len(value) > index:
                    return value[index]
                #value is smaller than expected
                #so return default value
            else:
                return value
        return self._getdefaultvalue(opt, path, with_meta, index,
                                     submulti_index, validate, _orig_context)

    def get_modified_values(self):
        return self._p_.get_modified_values()

    def __contains__(self, opt):
        """
        implements the 'in' keyword syntax in order provide a pythonic way
        to kow if an option have a value

        :param opt: the `option.Option()` object
        """
        path = opt.impl_getpath(self._getcontext())
        return self._contains(path)

    def _contains(self, path, session=None):
        if session is None:
            session = self._p_.getsession()
        return self._p_.hasvalue(path, session)

    def __delitem__(self, opt):
        """overrides the builtins `del()` instructions"""
        self.reset(opt)

    def reset(self, opt, path=None, validate=True, _setting_properties=None, _commit=True):
        context = self._getcontext()
        setting = context.cfgimpl_get_settings()
        if path is None:
            path = opt.impl_getpath(context)
        if _setting_properties is None:
            _setting_properties = setting._getproperties(read_write=False)
        session = self._p_.getsession()
        hasvalue = self._contains(path, session)

        if validate and hasvalue and 'validator' in _setting_properties:
            session = context.cfgimpl_get_values()._p_.getsession()
            fake_context = context._gen_fake_values(session)
            fake_value = fake_context.cfgimpl_get_values()
            fake_value.reset(opt, path, validate=False)
            ret = fake_value._get_cached_value(opt, path,
                                               setting_properties=_setting_properties,
                                               check_frozen=True)
            if isinstance(ret, Exception):
                raise ret
        if opt.impl_is_master_slaves('master'):
            opt.impl_get_master_slaves().reset(opt, self, _setting_properties, _commit=_commit)
        if hasvalue:
            if 'force_store_value' in setting._getproperties(opt=opt,
                                                             path=path,
                                                             setting_properties=_setting_properties,
                                                             read_write=False,
                                                             apply_requires=False):
                value = self._getdefaultvalue(opt, path, True, undefined, undefined, validate)
                if isinstance(value, Exception):  # pragma: no cover
                    raise value
                self._setvalue(opt, path, value, force_owner=owners.forced, commit=_commit)
            else:
                self._p_.resetvalue(path, session, _commit)
            context.cfgimpl_reset_cache(opt=opt, path=path, only=('values', 'properties'))

    def _isempty(self, opt, value, force_allow_empty_list=False, index=None):
        "convenience method to know if an option is empty"
        if value is undefined:
            return False
        else:
            empty = opt._empty
            if index in [None, undefined] and opt.impl_is_multi():
                if force_allow_empty_list:
                    allow_empty_list = True
                else:
                    allow_empty_list = opt.impl_allow_empty_list()
                    if allow_empty_list is undefined:
                        if opt.impl_is_master_slaves('slave'):
                            allow_empty_list = True
                        else:
                            allow_empty_list = False
                isempty = value is None or (not allow_empty_list and value == []) or \
                    None in value or empty in value
            else:
                isempty = value is None or value == empty
        return isempty

    def __getitem__(self, opt):
        "enables us to use the pythonic dictionary-like access to values"
        return self._get_cached_value(opt)

    def _get_cached_value(self, opt, path=None, validate=True,
                          force_permissive=False, trusted_cached_properties=True,
                          validate_properties=True,
                          setting_properties=undefined, self_properties=undefined,
                          index=None, submulti_index=undefined, from_masterslave=False,
                          with_meta=True, masterlen=undefined, check_frozen=False,
                          session=None, display_warnings=True, _orig_context=undefined):
        context = self._getcontext()
        settings = context.cfgimpl_get_settings()
        if path is None:
            path = opt.impl_getpath(context)
        ntime = None
        if setting_properties is undefined:
            setting_properties = settings._getproperties(read_write=False)
        if self_properties is undefined:
            self_properties = settings._getproperties(opt, path,
                                                      read_write=False,
                                                      setting_properties=setting_properties,
                                                      index=index)
        if 'cache' in setting_properties and self._p_.hascache(path, index) and \
                _orig_context is undefined:
            if 'expire' in setting_properties:
                ntime = int(time())
            is_cached, value = self._p_.getcache(path, ntime, None)
            if index:
                value = value[index]
            if is_cached:
                if opt.impl_is_multi() and not isinstance(value, Multi) and index is None:
                    value = Multi(value, self.context, opt, path)
                if not trusted_cached_properties:
                    # revalidate properties (because of not default properties)
                    props = settings.validate_properties(opt, False, False, value=value,
                                                         path=path,
                                                         force_permissive=force_permissive,
                                                         setting_properties=setting_properties,
                                                         self_properties=self_properties,
                                                         index=index)
                    if props:
                        return props
                return value
        if session is None:
            session = self._p_.getsession()
        if not from_masterslave and opt.impl_is_master_slaves():
            val = opt.impl_get_master_slaves().getitem(self, opt, path,
                                                       validate,
                                                       force_permissive,
                                                       trusted_cached_properties,
                                                       validate_properties,
                                                       session,
                                                       setting_properties=setting_properties,
                                                       index=index,
                                                       self_properties=self_properties,
                                                       check_frozen=check_frozen)
        else:
            val = self._get_validated_value(opt, path, validate,
                                            force_permissive,
                                            validate_properties,
                                            setting_properties,
                                            self_properties,
                                            with_meta=with_meta,
                                            masterlen=masterlen,
                                            index=index,
                                            submulti_index=submulti_index,
                                            check_frozen=check_frozen,
                                            session=session,
                                            display_warnings=display_warnings,
                                            _orig_context=_orig_context)
        if isinstance(val, Exception):
            return val
        # cache doesn't work with SubMulti yet
        if index is None and not isinstance(val, SubMulti) and 'cache' in setting_properties and \
                validate and validate_properties and force_permissive is False \
                and trusted_cached_properties is True and _orig_context is undefined:
            if 'expire' in setting_properties:
                if ntime is None:
                    ntime = int(time())
                ntime = ntime + expires_time
            self._p_.setcache(path, val, ntime, None)
        return val

    def _get_validated_value(self, opt, path, validate, force_permissive,
                             validate_properties, setting_properties,
                             self_properties,
                             index=None, submulti_index=undefined,
                             with_meta=True,
                             masterlen=undefined,
                             check_frozen=False,
                             session=None, display_warnings=True,
                             _orig_context=undefined):
        """same has getitem but don't touch the cache
        index is None for slave value, if value returned is not a list, just return []
        """
        context = self._getcontext()
        setting = context.cfgimpl_get_settings()
        config_error = None
        if session is None:
            session = self._p_.getsession()
        value = self._getvalue(opt, path, self_properties, index, submulti_index,
                               with_meta, masterlen, session, validate, _orig_context)
        if isinstance(value, Exception):
            value_error = True
            if isinstance(value, ConfigError):
                # For calculating properties, we need value (ie for mandatory
                # value).
                # If value is calculating with a PropertiesOptionError's option
                # _getvalue raise a ConfigError.
                # We can not raise ConfigError if this option should raise
                # PropertiesOptionError too. So we get config_error and raise
                # ConfigError if properties did not raise.
                config_error = value
                # value is not set, for 'undefined' (cannot set None because of
                # mandatory property)
                value = undefined
            else:  # pragma: no cover
                raise value
        else:
            value_error = False
            if opt.impl_is_multi():
                if index is None:
                    value = Multi(value, self.context, opt, path)
                elif opt.impl_is_submulti() and submulti_index is undefined:
                    value = SubMulti(value, self.context, opt, path,
                                     index)

            if validate:
                if submulti_index is undefined:
                    force_submulti_index = None
                else:
                    force_submulti_index = submulti_index
                err = opt.impl_validate(value, context,
                                        'validator' in setting_properties,
                                        force_index=index,
                                        force_submulti_index=force_submulti_index,
                                        display_error=True,
                                        display_warnings=False,
                                        setting_properties=setting_properties)
                if err:
                    config_error = err
                    value = None

        if validate_properties:
            if config_error is not None:
                # should not raise PropertiesOptionError if option is
                # mandatory
                val_props = undefined
            else:
                val_props = value
            props = setting.validate_properties(opt, False, check_frozen, value=val_props,
                                                path=path,
                                                force_permissive=force_permissive,
                                                setting_properties=setting_properties,
                                                self_properties=self_properties,
                                                index=index)
            if props:
                return props
        if not value_error and validate and display_warnings:
            opt.impl_validate(value, context,
                              'validator' in setting_properties,
                              force_index=index,
                              force_submulti_index=force_submulti_index,
                              display_error=False,
                              display_warnings=display_warnings,
                              setting_properties=setting_properties)
        if config_error is not None:
            return config_error
        return value

    def __setitem__(self, opt, value):
        raise ConfigError(_('you should only set value with config'))

    def setitem(self, opt, value, path, force_permissive=False,
                check_frozen=True, not_raises=False, index=None,
                _setting_properties=undefined, _commit=True):
        # check_frozen is, for example, used with "force_store_value"
        # user didn't change value, so not write
        # valid opt
        context = self._getcontext()
        if 'validator' in _setting_properties:
            session = context.cfgimpl_get_values()._p_.getsession()
            if opt._has_consistencies():
                fake_context = context._gen_fake_values(session)
                fake_values = fake_context.cfgimpl_get_values()
                fake_values._setvalue(opt, path, value, index=index)
            else:
                fake_context = context
                fake_values = self
            props = fake_values.validate(opt, value, path,
                                         check_frozen=check_frozen,
                                         force_permissive=force_permissive,
                                         setting_properties=_setting_properties,
                                         session=session, not_raises=not_raises,
                                         index=index, setitem=True)
            if props and not_raises:
                return props
            err = opt.impl_validate(value, fake_context, display_warnings=False, force_index=index,
                                    setting_properties=_setting_properties)
            if err:
                if not_raises:
                    return err
                raise err
            opt.impl_validate(value, fake_context, display_error=False,
                              setting_properties=_setting_properties)
        self._setvalue(opt, path, value, index=index, commit=_commit)

    def _setvalue(self, opt, path, value, force_owner=undefined, index=None, commit=True):
        context = self._getcontext()
        context.cfgimpl_reset_cache(opt=opt, path=path, only=('values', 'properties'))
        if force_owner is undefined:
            owner = context.cfgimpl_get_settings().getowner()
        else:
            owner = force_owner
        # in storage, value must not be a multi
        if isinstance(value, Multi):
            if not opt.impl_is_master_slaves('slave') or index is None:
                value = list(value)
                if opt.impl_is_submulti():
                    for idx, val in enumerate(value):
                        if isinstance(val, SubMulti):
                            value[idx] = list(val)
            else:
                value = value[index]
        session = self._p_.getsession()
        #FIXME pourquoi là et pas dans masterslaves ??
        if opt.impl_is_master_slaves('slave'):
            if index is not None:
                self._p_.setvalue(path, value, owner, index, session, commit)
            else:
                self._p_.resetvalue(path, session, commit)
                for idx, val in enumerate(value):
                    self._p_.setvalue(path, val, owner, idx, session, commit)
        else:
            self._p_.setvalue(path, value, owner, None, session, commit)
        del(session)

    def validate(self, opt, value, path, check_frozen=True, force_permissive=False,
                 setting_properties=undefined, valid_masterslave=True,
                 not_raises=False, session=None, index=None, setitem=False):
        if valid_masterslave and opt.impl_is_master_slaves():
            if session is None:
                session = self._p_.getsession()
            if opt.impl_is_master_slaves('master'):
                masterlen = len(value)
                slavelen = None
            else:
                masterlen = None
                slavelen = len(value)
            setitem = True
            opt.impl_get_master_slaves().impl_validate(self._getcontext(), force_permissive,
                                                       setting_properties, masterlen=masterlen,
                                                       slavelen=slavelen, opt=opt, setitem=True)
            #val = opt.impl_get_master_slaves().impl_validate(self, opt, len_value, path, session, setitem=setitem)
            #if isinstance(val, Exception):
            #    return val
        props = self._getcontext().cfgimpl_get_settings().validate_properties(opt,
                                                                              False,
                                                                              check_frozen,
                                                                              value=value,
                                                                              path=path,
                                                                              force_permissive=force_permissive,
                                                                              setting_properties=setting_properties,
                                                                              index=index)
        if props:
            if not_raises:
                return props
            raise props

    def _is_meta(self, opt, path, session=None, force_permissive=False):
        context = self._getcontext()
        if context.cfgimpl_get_meta() is None:
            return False
        setting = context.cfgimpl_get_settings()
        self_properties = setting._getproperties(opt, path, read_write=False)
        if session is None:
            session = self._p_.getsession()
        return self.is_default_owner(opt, path=path, validate_properties=True,
                                     validate_meta=False, index=None,
                                     force_permissive=force_permissive)

    def getowner(self, opt, index=None, force_permissive=False, session=None):
        """
        retrieves the option's owner

        :param opt: the `option.Option` object
        :param force_permissive: behaves as if the permissive property
                                 was present
        :returns: a `setting.owners.Owner` object
        """
        if opt._is_symlinkoption() and \
                not isinstance(opt, DynSymLinkOption):
            opt = opt._impl_getopt()
        path = opt.impl_getpath(self._getcontext())
        return self._getowner(opt, path, session, index=index, force_permissive=force_permissive)

    def _getowner(self, opt, path, session, validate_properties=True,
                  force_permissive=False, validate_meta=undefined,
                  self_properties=undefined, only_default=False,
                  index=None):
        """get owner of an option
        """
        if session is None:
            session = self._p_.getsession()
        if not isinstance(opt, Option) and not isinstance(opt,
                                                          DynSymLinkOption):
            raise ConfigError(_('owner only avalaible for an option'))
        context = self._getcontext()
        if self_properties is undefined:
            self_properties = context.cfgimpl_get_settings()._getproperties(
                opt, path, read_write=False)
        if 'frozen' in self_properties and 'force_default_on_freeze' in self_properties:
            return owners.default
        if validate_properties:
            value = self._get_cached_value(opt, path, True, force_permissive, None, True,
                                           self_properties=self_properties, session=session,
                                           index=index)
            if isinstance(value, Exception):
                raise value

        owner = self._p_.getowner(path, owners.default, session, only_default=only_default, index=index)
        if validate_meta is undefined:
            if opt.impl_is_master_slaves('slave'):
                master = opt.impl_get_master_slaves().getmaster(opt)
                masterp = master.impl_getpath(context)
                validate_meta = self._is_meta(master, masterp, session)
            else:
                validate_meta = True
        if validate_meta and owner is owners.default:
            meta = context.cfgimpl_get_meta()
            if meta is not None:
                owner = meta.cfgimpl_get_values()._getowner(opt, path, session,
                                                            validate_properties=validate_properties,
                                                            force_permissive=force_permissive,
                                                            self_properties=self_properties,
                                                            only_default=only_default, index=index)
        return owner

    def setowner(self, opt, owner, index=None):
        """
        sets a owner to an option

        :param opt: the `option.Option` object
        :param owner: a valid owner, that is a `setting.owners.Owner` object
        """
        if not isinstance(owner, owners.Owner):
            raise TypeError(_("invalid generic owner {0}").format(str(owner)))

        path = opt.impl_getpath(self._getcontext())
        session = self._p_.getsession()
        if not self._p_.hasvalue(path, session):
            raise ConfigError(_('no value for {0} cannot change owner to {1}'
                                '').format(path, owner))
        props = self._getcontext().cfgimpl_get_settings().validate_properties(opt,
                                                                              False,
                                                                              True,
                                                                              path,
                                                                              index=index)
        if props:
            raise props
        self._p_.setowner(path, owner, session, index=index)

    def is_default_owner(self, opt, path=None, validate_properties=True,
                         validate_meta=True, index=None,
                         force_permissive=False):
        """
        :param config: *must* be only the **parent** config
                       (not the toplevel config)
        :return: boolean
        """
        if path is None:
            path = opt.impl_getpath(self._getcontext())
        return self._is_default_owner(opt, path, session=None,
                                      validate_properties=validate_properties,
                                      validate_meta=validate_meta, index=index,
                                      force_permissive=force_permissive)

    def _is_default_owner(self, opt, path, session, validate_properties=True,
                          validate_meta=True, self_properties=undefined,
                          index=None, force_permissive=False):
        d = self._getowner(opt, path, session, validate_properties=validate_properties,
                           validate_meta=validate_meta,
                           self_properties=self_properties, only_default=True,
                           index=index, force_permissive=force_permissive)
        return d == owners.default

    # information
    def set_information(self, key, value):
        """updates the information's attribute

        :param key: information's key (ex: "help", "doc"
        :param value: information's value (ex: "the help string")
        """
        self._p_.set_information(key, value)

    def get_information(self, key, default=undefined):
        """retrieves one information's item

        :param key: the item string (ex: "help")
        """
        return self._p_.get_information(key, default)

    def del_information(self, key, raises=True):
        self._p_.del_information(key, raises)

    def mandatory_warnings(self, force_permissive=True):
        """convenience function to trace Options that are mandatory and
        where no value has been set

        :returns: generator of mandatory Option's path
        """
        context = self._getcontext()
        settings = context.cfgimpl_get_settings()
        setting_properties = context.cfgimpl_get_settings()._getproperties()
        setting_properties.update(['mandatory', 'empty'])
        def _is_properties_option(err, path):
            if not isinstance(err, Exception):
                pass
            elif isinstance(err, PropertiesOptionError):
                if err.proptype == ['mandatory']:
                    return path
            elif isinstance(err, ConfigError):
                #assume that uncalculated value is an empty value
                return path
            else:
                raise err

        def _mandatory_warnings(description, currpath=None):
            if currpath is None:
                currpath = []
            for opt in description._impl_getchildren(context=context):
                name = opt.impl_getname()
                path = '.'.join(currpath + [name])

                if opt.impl_is_optiondescription():
                    if not settings.validate_properties(opt, True, False, path=path,
                                                        force_permissive=True,
                                                        setting_properties=setting_properties):
                        for path in _mandatory_warnings(opt, currpath + [name]):
                            yield path
                else:
                    if opt._is_symlinkoption() and \
                            not isinstance(opt, DynSymLinkOption):
                        continue
                    self_properties = settings._getproperties(opt, path,
                                                              read_write=False,
                                                              setting_properties=setting_properties)
                    if 'mandatory' in self_properties or 'empty' in self_properties:
                        err = self._get_cached_value(opt, path=path,
                                                     trusted_cached_properties=False,
                                                     force_permissive=True,
                                                     setting_properties=setting_properties,
                                                     self_properties=self_properties,
                                                     validate=True,
                                                     display_warnings=False)
                        if opt.impl_is_master_slaves('slave') and isinstance(err, list):
                            for val in err:
                                ret = _is_properties_option(val, path)
                                if ret is not None:
                                    yield ret
                                    break
                        else:
                            ret = _is_properties_option(err, path)
                            if ret is not None:
                                yield ret

        descr = context.cfgimpl_get_description()
        for path in _mandatory_warnings(descr):
            yield path

    def force_cache(self):
        """parse all option to force data in cache
        """
        context = self.context()
        if not 'cache' in context.cfgimpl_get_settings():
            raise ConfigError(_('can force cache only if cache '
                                'is actived in config'))
        context.cfgimpl_reset_cache()
        for path in context.cfgimpl_get_description().impl_getpaths(
                include_groups=True):
            err = context.getattr(path, returns_raise=True)
            if isinstance(err, Exception) and not isinstance(err, PropertiesOptionError):  # pragma: no cover
                raise err


# ____________________________________________________________
# multi types
class Multi(list):
    """multi options values container
    that support item notation for the values of multi options"""
    __slots__ = ('opt', 'path', 'context', '__weakref__')

    def __init__(self, value, context, opt, path):
        """
        :param value: the Multi wraps a list value
        :param context: the home config that has the values
        :param opt: the option object that have this Multi value
        :param path: path of the option
        """
        if value is None:
            value = []
        if not opt.impl_is_submulti() and isinstance(value, Multi):
            raise ValueError(_('{0} is already a Multi ').format(
                opt.impl_getname()))
        self.opt = opt
        self.path = path
        if not isinstance(context, weakref.ReferenceType):
            raise ValueError('context must be a Weakref')
        self.context = context
        if not isinstance(value, list):
            if not '_index' in self.__slots__ and opt.impl_is_submulti():
                value = [[value]]
            else:
                value = [value]
        elif value != [] and not '_index' in self.__slots__ and \
                opt.impl_is_submulti() and not isinstance(value[0], list):
            value = [value]
        super(Multi, self).__init__(value)
        if opt.impl_is_submulti():
            if not '_index' in self.__slots__:
                for idx, val in enumerate(self):
                    if not isinstance(val, SubMulti):
                        super(Multi, self).__setitem__(idx, SubMulti(val,
                                                                     context,
                                                                     opt, path,
                                                                     idx))
                    self[idx].refmulti = weakref.ref(self)

    def _getcontext(self):
        """context could be None, we need to test it
        context is None only if all reference to `Config` object is deleted
        (for example we delete a `Config` and we manipulate a reference to
        old `SubConfig`, `Values`, `Multi` or `Settings`)
        """
        context = self.context()
        if context is None:
            raise ConfigError(_('the context does not exist anymore'))
        return context

    def __setitem__(self, index, value):
        self._setitem(index, value)

    def _setitem(self, index, value, validate=True):
        context = self._getcontext()
        setting = context.cfgimpl_get_settings()
        setting_properties = setting._getproperties(read_write=False)
        if index < 0:
            index = self.__len__() + index
        if 'validator' in setting_properties and validate:
            session = context.cfgimpl_get_values()._p_.getsession()
            fake_context = context._gen_fake_values(session)
            fake_multi = Multi(list(self), weakref.ref(fake_context), self.opt, self.path)
            fake_multi._setitem(index, value, validate=False)
            self._validate(value, fake_context, index, True)
        #assume not checking mandatory property
        super(Multi, self).__setitem__(index, value)
        self._store(index=index)

    #def __repr__(self, *args, **kwargs):
    #    return super(Multi, self).__repr__(*args, **kwargs)

    def __getitem__(self, index):
        value = super(Multi, self).__getitem__(index)
        if isinstance(value, PropertiesOptionError):
            raise value
        return value

    def __delitem__(self, index):
        return self.pop(index)

    def _getdefaultvalue(self, index):
        values = self._getcontext().cfgimpl_get_values()
        value = values._getdefaultvalue(self.opt, self.path, True, index,
                                        undefined, True)
        if self.opt.impl_is_submulti():
            value = SubMulti(value, self.context, self.opt, self.path, index)
        return value

    def append(self, value=undefined, force=False, setitem=True, validate=True,
               force_permissive=False):
        """the list value can be updated (appened)
        only if the option is a master
        """
        if not force and self.opt.impl_is_master_slaves('slave'):
            raise SlaveError(_("cannot append a value on a multi option {0}"
                               " which is a slave").format(self.opt.impl_getname()))
        index = self.__len__()
        if value is undefined:
            value = self._getdefaultvalue(index)
        if validate and value not in [None, undefined]:
            context = self._getcontext()
            setting = context.cfgimpl_get_settings()
            setting_properties = setting._getproperties(read_write=False)
            if 'validator' in setting_properties:
                session = context.cfgimpl_get_values()._p_.getsession()
                fake_context = context._gen_fake_values(session)
                fake_multi = Multi(list(self), weakref.ref(fake_context), self.opt, self.path)
                fake_multi.append(value, validate=False, force=True,
                                  setitem=setitem)
                self._validate(value, fake_context, index, True)
        if not '_index' in self.__slots__ and self.opt.impl_is_submulti():
            if not isinstance(value, SubMulti):
                value = SubMulti(value, self.context, self.opt, self.path, index)
            value.refmulti = weakref.ref(self)
        super(Multi, self).append(value)
        if setitem:
            self._store(force=force)

    def append_properties_error(self, err):
        super(Multi, self).append(err)

    def sort(self, cmp=None, key=None, reverse=False):
        if self.opt.impl_is_master_slaves():
            raise SlaveError(_("cannot sort multi option {0} if master or slave"
                               "").format(self.opt.impl_getname()))
        if sys.version_info[0] >= 3:  # pragma: no cover
            if cmp is not None:
                raise ValueError(_('cmp is not permitted in python v3 or '
                                   'greater'))
            super(Multi, self).sort(key=key, reverse=reverse)
        else:
            super(Multi, self).sort(cmp=cmp, key=key, reverse=reverse)
        self._store()

    def reverse(self):
        if self.opt.impl_is_master_slaves():
            raise SlaveError(_("cannot reverse multi option {0} if master or "
                               "slave").format(self.opt.impl_getname()))
        super(Multi, self).reverse()
        self._store()

    def insert(self, index, value, validate=True):
        if self.opt.impl_is_master_slaves():
            raise SlaveError(_("cannot insert multi option {0} if master or "
                               "slave").format(self.opt.impl_getname()))
        context = self._getcontext()
        setting = setting = context.cfgimpl_get_settings()
        setting_properties = setting._getproperties(read_write=False)
        if 'validator' in setting_properties and validate and value is not None:
            session = context.cfgimpl_get_values()._p_.getsession()
            fake_context = context._gen_fake_values(session)
            fake_multi = Multi(list(self), weakref.ref(fake_context), self.opt, self.path)
            fake_multi.insert(index, value, validate=False)
            self._validate(value, fake_context, index, True)
        super(Multi, self).insert(index, value)
        self._store()

    def extend(self, iterable, validate=True):
        if self.opt.impl_is_master_slaves():
            raise SlaveError(_("cannot extend multi option {0} if master or "
                               "slave").format(self.opt.impl_getname()))
        index = getattr(self, '_index', None)
        context = self._getcontext()
        setting = context.cfgimpl_get_settings()
        setting_properties = setting._getproperties(read_write=False)
        if 'validator' in setting_properties and validate:
            session = context.cfgimpl_get_values()._p_.getsession()
            fake_context = context._gen_fake_values(session)
            fake_multi = Multi(list(self), weakref.ref(fake_context), self.opt, self.path)
            if index is None:
                fake_multi.extend(iterable, validate=False)
                self._validate(fake_multi, fake_context, index)
            else:
                fake_multi[index].extend(iterable, validate=False)
                self._validate(fake_multi[index], fake_context, index)
        super(Multi, self).extend(iterable)
        self._store()

    def _validate(self, value, fake_context, force_index, submulti=False):
        err = self.opt.impl_validate(value, context=fake_context,
                                     force_index=force_index,
                                     multi=self)
        if err:
            raise err

    def pop(self, index, force=False):
        """the list value can be updated (poped)
        only if the option is a master

        :param index: remove item a index
        :type index: int
        :param force: force pop item (withoud check master/slave)
        :type force: boolean
        :returns: item at index
        """
        context = self._getcontext()
        if not force:
            if self.opt.impl_is_master_slaves('slave'):
                raise SlaveError(_("cannot pop a value on a multi option {0}"
                                   " which is a slave").format(self.opt.impl_getname()))
            if self.opt.impl_is_master_slaves('master'):
                self.opt.impl_get_master_slaves().pop(self.opt,
                                                      context.cfgimpl_get_values(), index)
        #set value without valid properties
        ret = super(Multi, self).pop(index)
        self._store(force=force)
        return ret

    def remove(self, value):
        idx = self.index(value)
        return self.pop(idx)

    def _store(self, force=False, index=None):
        values = self._getcontext().cfgimpl_get_values()
        if not force:
            #FIXME could get properties an pass it
            values.validate(self.opt, self, self.path, valid_masterslave=False)
        values._setvalue(self.opt, self.path, self, index=index)


class SubMulti(Multi):
    __slots__ = ('_index', 'refmulti')

    def __init__(self, value, context, opt, path, index):
        """
        :param index: index (only for slave with submulti)
        :type index: `int`
        """
        self._index = index
        super(SubMulti, self).__init__(value, context, opt, path)

    def append(self, value=undefined):
        super(SubMulti, self).append(value, force=True)

    def pop(self, index):
        return super(SubMulti, self).pop(index, force=True)

    def __setitem__(self, index, value):
        self._setitem(index, value)

    def _store(self, force=False, index=None):
        #force is unused here
        values = self._getcontext().cfgimpl_get_values()
        values.validate(self.opt, self, self.path, valid_masterslave=False)
        multi = self.refmulti()
        if multi is None:
            multi = values._get_cached_value(self.opt, path=self.path)
            multi[self._index] = self
        values._setvalue(self.opt, self.path, multi)

    def _validate(self, value, fake_context, force_index, submulti=False):
        if value is not None:
            if submulti is False:
                super(SubMulti, self)._validate(value, fake_context,
                                                force_index, submulti)
            else:
                err = self.opt.impl_validate(value, context=fake_context,
                                             force_index=self._index,
                                             force_submulti_index=force_index,
                                             multi=self)
                if err:
                    raise err

    def _getdefaultvalue(self, index):
        values = self._getcontext().cfgimpl_get_values()
        return values._getdefaultvalue(self.opt, self.path, True, index,
                                       self._index, True)