tiramisu/tiramisu/setting.py

# -*- coding: utf-8 -*-
"sets the options of the configuration objects Config object itself"
# Copyright (C) 2012-2017 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
from copy import copy
from logging import getLogger
import weakref
from .error import (RequirementError, PropertiesOptionError,
                    ConstError, ConfigError, display_list)
from .i18n import _


"Default encoding for display a Config if raise UnicodeEncodeError"
default_encoding = 'utf-8'

"""If cache and expire is enable, time before cache is expired.
This delay start first time value/setting is set in cache, even if
user access several time to value/setting
"""
expires_time = 5
"""List of default properties (you can add new one if needed).

For common properties and personalise properties, if a propery is set for
an Option and for the Config together, Setting raise a PropertiesOptionError

* Common properties:

hidden
    option with this property can only get value in read only mode. This
    option is not available in read write mode.

disabled
    option with this property cannot be set/get

frozen
    cannot set value for option with this properties if 'frozen' is set in
    config

mandatory
    should set value for option with this properties if 'mandatory' is set in
    config


* Special property:

permissive
    option with 'permissive' cannot raise PropertiesOptionError for properties
    set in permissive
    config with 'permissive', whole option in this config cannot raise
    PropertiesOptionError for properties set in permissive

* Special Config properties:

cache
    if set, enable cache settings and values

expire
    if set, settings and values in cache expire after ``expires_time``

everything_frozen
    whole option in config are frozen (even if option have not frozen
    property)

empty
    raise mandatory PropertiesOptionError if multi or master have empty value

validator
    launch validator set by user in option (this property has no effect
    for internal validator)

warnings
    display warnings during validation
"""
default_properties = ('cache', 'expire', 'validator', 'warnings')

"""Config can be in two defaut mode:

read_only
    you can get all variables not disabled but you cannot set any variables
    if a value has a callback without any value, callback is launch and value
    of this variable can change
    you cannot access to mandatory variable without values

read_write
    you can get all variables not disabled and not hidden
    you can set all variables not frozen
"""
ro_append = set(['frozen', 'disabled', 'validator', 'everything_frozen',
                'mandatory', 'empty'])
ro_remove = set(['permissive', 'hidden'])
rw_append = set(['frozen', 'disabled', 'validator', 'hidden'])
rw_remove = set(['permissive', 'everything_frozen', 'mandatory', 'empty'])


forbidden_set_properties = frozenset(['force_store_value'])
forbidden_set_permissives = frozenset(['frozen', 'force_default_on_freeze'])


log = getLogger('tiramisu')
#FIXME
#import logging
#logging.basicConfig(format='%(levelname)s:%(message)s', level=logging.DEBUG)
debug = False
static_set = frozenset()


# ____________________________________________________________
class _NameSpace(object):
    """convenient class that emulates a module
    and builds constants (that is, unique names)
    when attribute is added, we cannot delete it
    """

    def __setattr__(self,
                    name,
                    value):
        if name in self.__dict__:
            raise ConstError(_("can't rebind {0}").format(name))
        self.__dict__[name] = value

    def __delattr__(self,
                    name):
        raise ConstError(_("can't unbind {0}").format(name))


class GroupModule(_NameSpace):
    "emulates a module to manage unique group (OptionDescription) names"
    class GroupType(str):
        """allowed normal group (OptionDescription) names
        *normal* means : groups that are not master
        """
        pass

    class DefaultGroupType(GroupType):
        """groups that are default (typically 'default')"""
        pass

    class MasterGroupType(GroupType):
        """allowed normal group (OptionDescription) names
        *master* means : groups that have the 'master' attribute set
        """
        pass


class OwnerModule(_NameSpace):
    """emulates a module to manage unique owner names.

    owners are living in `Config._cfgimpl_value_owners`
    """
    class Owner(str):
        """allowed owner names
        """
        pass

    class DefaultOwner(Owner):
        """groups that are default (typically 'default')"""
        pass

    def addowner(self, name):
        """
        :param name: the name of the new owner
        """
        setattr(owners, name, owners.Owner(name))


# ____________________________________________________________
# populate groups
groups = GroupModule()
"""groups.default
        default group set when creating a new optiondescription"""
groups.default = groups.DefaultGroupType('default')

"""groups.master
        master group is a special optiondescription, all suboptions should be
        multi option and all values should have same length, to find master's
        option, the optiondescription's name should be same than de master's
        option"""
groups.master = groups.MasterGroupType('master')

"""    groups.family
        example of group, no special behavior with this group's type"""
groups.family = groups.GroupType('family')


# ____________________________________________________________
# populate owners with default attributes
owners = OwnerModule()
"""default
        is the config owner after init time"""
owners.default = owners.DefaultOwner('default')
"""user
        is the generic is the generic owner"""
owners.user = owners.Owner('user')
"""forced
        special owner when value is forced"""
owners.forced = owners.Owner('forced')
"""meta
        special owner when value comes from metaconfig"""
owners.meta = owners.Owner('meta')


forbidden_owners = (owners.default, owners.forced, owners.meta)


# ____________________________________________________________
class Undefined(object):
    pass


undefined = Undefined()


#____________________________________________________________
class Settings(object):
    "``config.Config()``'s configuration options settings"
    __slots__ = ('context', '_owner', '_p_', '_pp_', '__weakref__')

    def __init__(self, context, properties, permissives):
        """
        initializer

        :param context: the root config
        :param storage: the storage type

                        - dictionary -> in memory
                        - sqlite3 -> persistent
        """
        # generic owner
        self._owner = owners.user
        self.context = weakref.ref(context)
        self._p_ = properties
        self._pp_ = permissives

    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:  # pragma: optional cover
            raise ConfigError(_('the context does not exist anymore'))
        return context

    #____________________________________________________________
    # get properties and permissive methods

    def get_context_properties(self):
        ntime = int(time())
        if self._p_.hascache(None,
                             None):
            is_cached, props = self._p_.getcache(None,
                                                 ntime,
                                                 None)
        else:
            is_cached = False
        if not is_cached or 'cache' not in props:
            meta = self._getcontext().cfgimpl_get_meta()
            if meta is None:
                props = self._p_.getproperties(None,
                                               default_properties)
            else:
                props = meta.cfgimpl_get_settings().get_context_properties()
            if 'cache' in props:
                if 'expire' in props:
                    ntime = ntime + expires_time
                else:
                    ntime = None
                self._p_.setcache(None, props, ntime, None)
        return props

    def getproperties(self,
                      opt,
                      path,
                      setting_properties,
                      index=None,
                      apply_requires=True):
        """
        """
        is_cached = False

        if apply_requires:
            if 'cache' in setting_properties and 'expire' in setting_properties:
                ntime = int(time())
            else:
                ntime = None
            if 'cache' in setting_properties and self._p_.hascache(path,
                                                                   index):
                is_cached, props = self._p_.getcache(path,
                                                     ntime,
                                                     index)
        if not is_cached:
            meta = self._getcontext().cfgimpl_get_meta()
            if meta is None:
                props = self._p_.getproperties(path,
                                               opt.impl_getproperties())
            else:
                props = meta.cfgimpl_get_settings().getproperties(opt,
                                                                  path,
                                                                  setting_properties,
                                                                  index=index,
                                                                  apply_requires=False)
            if apply_requires:
                requires = self.apply_requires(opt,
                                               path,
                                               setting_properties,
                                               index,
                                               False)
                #FIXME devrait etre un frozenset!
                if requires != set([]):
                    props = copy(props)
                    props |= requires

            props -= self.getpermissive(path)
            if apply_requires and 'cache' in setting_properties:
                if 'expire' in setting_properties:
                    ntime = ntime + expires_time
                self._p_.setcache(path,
                                  props,
                                  ntime,
                                  index)
        return props

    def get_context_permissive(self):
        return self.getpermissive(None)

    def getpermissive(self,
                      path):
        meta = self._getcontext().cfgimpl_get_meta()
        if meta is None:
            return self._pp_.getpermissive(path)
        return meta.cfgimpl_get_settings().getpermissive(path)

    def apply_requires(self,
                       opt,
                       path,
                       setting_properties,
                       index,
                       debug):
        """carries out the jit (just in time) requirements between options

        a requirement is a tuple of this form that comes from the option's
        requirements validation::

            (option, expected, action, inverse, transitive, same_action)

        let's have a look at all the tuple's items:

        - **option** is the target option's

        - **expected** is the target option's value that is going to trigger
          an action

        - **action** is the (property) action to be accomplished if the target
          option happens to have the expected value

        - if **inverse** is `True` and if the target option's value does not
          apply, then the property action must be removed from the option's
          properties list (wich means that the property is inverted)

        - **transitive**: but what happens if the target option cannot be
          accessed ? We don't kown the target option's value. Actually if some
          property in the target option is not present in the permissive, the
          target option's value cannot be accessed. In this case, the
          **action** have to be applied to the option. (the **action** property
          is then added to the option).

        - **same_action**: actually, if **same_action** is `True`, the
          transitivity is not accomplished. The transitivity is accomplished
          only if the target option **has the same property** that the demanded
          action. If the target option's value is not accessible because of
          another reason, because of a property of another type, then an
          exception :exc:`~error.RequirementError` is raised.

        And at last, if no target option matches the expected values, the
        action will not add to the option's properties list.

        :param opt: the option on wich the requirement occurs
        :type opt: `option.Option()`
        :param path: the option's path in the config
        :type path: str
        """
        current_requires = opt.impl_getrequires()

        # filters the callbacks
        if debug:
            calc_properties = {}
        else:
            calc_properties = set()

        if not current_requires:
            return calc_properties

        context = self._getcontext()
        all_properties = None
        for requires in current_requires:
            for require in requires:
                exps, action, inverse, \
                    transitive, same_action, operator = require
                breaked = False
                for exp in exps:
                    option, expected = exp
                    reqpath = option.impl_getpath(context)
                    if reqpath == path or reqpath.startswith(path + '.'):  # pragma: optional cover
                        raise RequirementError(_("malformed requirements "
                                                 "imbrication detected for option:"
                                                 " '{0}' with requirement on: "
                                                 "'{1}'").format(path, reqpath))
                    if option.impl_is_multi():
                        if index is None:
                            # multi is allowed only for slaves
                            # so do not calculated requires if no index
                            continue
                        idx = index
                    else:
                        idx = None
                    try:
                        value = context.getattr(reqpath,
                                                setting_properties,
                                                force_permissive=True,
                                                index=idx)
                    except PropertiesOptionError as err:
                        if not transitive:
                            if all_properties is None:
                                all_properties = []
                                for requires_ in opt.impl_getrequires():
                                    for require_ in requires_:
                                        all_properties.append(require_[1])
                            if not set(err.proptype) - set(all_properties):
                                continue
                        properties = err.proptype
                        if same_action and action not in properties:  # pragma: optional cover
                            if len(properties) == 1:
                                prop_msg = _('property')
                            else:
                                prop_msg = _('properties')
                            raise RequirementError(_('cannot access to option "{0}" because '
                                                     'required option "{1}" has {2} {3}'
                                                     '').format(opt.impl_get_display_name(),
                                                                option.impl_get_display_name(),
                                                                prop_msg,
                                                                display_list(properties)))
                        orig_value = err
                        # transitive action, force expected
                        value = expected[0]
                        inverse = False
                    else:
                        orig_value = value
                    if (not inverse and value in expected or
                            inverse and value not in expected):
                        if operator != 'and':
                            if debug:
                                if isinstance(orig_value, PropertiesOptionError):
                                    for msg in orig_value._settings.apply_requires(**orig_value._datas).values():
                                        calc_properties.setdefault(action, []).extend(msg)
                                else:
                                    if not inverse:
                                        msg = _('the value of "{0}" is "{1}"')
                                    else:
                                        msg = _('the value of "{0}" is not "{1}"')
                                    calc_properties.setdefault(action, []).append(
                                        msg.format(option.impl_get_display_name(),
                                                   display_list(expected, 'or')))
                            else:
                                calc_properties.add(action)
                                breaked = True
                                break
                    elif operator == 'and':
                        break
                else:
                    if operator == 'and':
                        calc_properties.add(action)
                    continue  # pragma: no cover
                if breaked:
                    break
        return calc_properties

    #____________________________________________________________
    # set methods
    def set_context_properties(self, properties):
        self.setproperties(None, None, properties)

    def setproperties(self,
                      opt,
                      path,
                      properties):
        """save properties for specified path
        (never save properties if same has option properties)
        """
        if self._getcontext().cfgimpl_get_meta() is not None:
            raise ConfigError(_('cannot change property with metaconfig'))
        forbidden_properties = forbidden_set_properties & properties
        if forbidden_properties:
            raise ConfigError(_('cannot add those properties: {0}').format(
                ' '.join(forbidden_properties)))
        if not isinstance(properties, frozenset):
            raise TypeError(_('properties must be a frozenset'))
        self._p_.setproperties(path,
                               properties)
        #values too because of slave values could have a PropertiesOptionError has value
        self._getcontext().cfgimpl_reset_cache(opt=opt,
                                               path=path)

    def set_context_permissive(self, permissive):
        self.setpermissive(None, None, permissive)

    def setpermissive(self,
                      opt,
                      path,
                      permissives):
        """
        enables us to put the permissives in the storage

        :param path: the option's path
        :param type: str
        :param opt: if an option object is set, the path is extracted.
                    it is better (faster) to set the path parameter
                    instead of passing a :class:`tiramisu.option.Option()` object.
        """
        if self._getcontext().cfgimpl_get_meta() is not None:
            raise ConfigError(_('cannot change permissive with metaconfig'))
        if not isinstance(permissives, frozenset):
            raise TypeError(_('permissive must be a frozenset'))
        forbidden_permissives = forbidden_set_permissives & permissives
        if forbidden_permissives:
            raise ConfigError(_('cannot add those permissives: {0}').format(
                ' '.join(forbidden_permissives)))
        self._pp_.setpermissive(path, permissives)
        self._getcontext().cfgimpl_reset_cache(opt=opt,
                                               path=path)

    #____________________________________________________________
    # reset methods

    def reset(self,
              opt=None,
              _path=None,
              all_properties=False):
        if self._getcontext().cfgimpl_get_meta() is not None:
            raise ConfigError(_('cannot change property with metaconfig'))
        if all_properties and (_path or opt):  # pragma: optional cover
            raise ValueError(_('opt and all_properties must not be set '
                               'together in reset'))
        if all_properties:
            self._p_.reset_all_properties()
        else:
            if opt is not None and _path is None:
                _path = opt.impl_getpath(self._getcontext())
            self._p_.delproperties(_path)
        self._getcontext().cfgimpl_reset_cache(opt=opt,
                                               path=_path)

    #____________________________________________________________
    # validate properties

    def validate_properties(self,
                            opt_or_descr,
                            path,
                            setting_properties,
                            index=None,
                            force_permissive=False):
        """
        validation upon the properties related to `opt_or_descr`

        :param opt_or_descr: an option or an option description object
        :param force_permissive: behaves as if the permissive property
                                 was present
        """
        # opt properties
        properties = self.getproperties(opt_or_descr,
                                        path,
                                        setting_properties=setting_properties,
                                        index=index)
        # calc properties
        properties &= setting_properties - set(['frozen'])
        if not opt_or_descr.impl_is_optiondescription():
            #mandatory
            if 'mandatory' in properties or 'empty' in properties:
                value = 'pouet'
                if self.validate_mandatory(opt_or_descr, index, value, properties):
                    properties += set(['mandatory']) - set(['empty'])
                else:
                    properties -= set(['mandatory', 'empty'])
            opt_type = 'option'
        else:
            opt_type = 'optiondescription'

        # remove permissive properties
        if force_permissive is True and properties:
            # remove global permissive if need
            properties -= self.get_context_permissive()

        # at this point an option should not remain in properties
        if properties != frozenset():
            datas = {'opt': opt_or_descr,
                     'path': path,
                     'setting_properties': setting_properties,
                     'index': index,
                     'debug': True}
            raise PropertiesOptionError(None,
                                        properties,
                                        self,
                                        datas,
                                        opt_type)

    def validate_mandatory(self, opt, index, value, properties):
        values = self._getcontext().cfgimpl_get_values()
        return 'mandatory' in properties and values.isempty(opt,
                                                            value,
                                                            index=index) or \
                'empty' in properties and values.isempty(opt,
                                                         value,
                                                         force_allow_empty_list=True,
                                                         index=index)

    #____________________________________________________________
    # read only/read write

    def _read(self,
              remove,
              append):
        props = self._p_.getproperties(None,
                                       default_properties)
        modified = False
        if remove & props != set([]):
            props = props - remove
            modified = True
        if append & props != append:
            props = props | append
            modified = True
        if modified:
            self.set_context_properties(frozenset(props))

    def read_only(self):
        "convenience method to freeze, hide and disable"
        self._read(ro_remove,
                   ro_append)

    def read_write(self):
        "convenience method to freeze, hide and disable"
        self._read(rw_remove,
                   rw_append)

    #____________________________________________________________
    # get modified properties/permissives

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

    def get_modified_permissives(self):
        return self._pp_.get_modified_permissives()

    #____________________________________________________________
    # default owner methods

    def setowner(self,
                 owner):
        ":param owner: sets the default value for owner at the Config level"
        if not isinstance(owner,
                          owners.Owner):  # pragma: optional cover
            raise TypeError(_("invalid generic owner {0}").format(str(owner)))
        self._owner = owner

    def getowner(self):
        return self._owner