tiramisu/tiramisu/setting.py

# -*- coding: utf-8 -*-
"sets the options of the configuration objects Config object itself"
# Copyright (C) 2012-2013 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 General Public License as published by
# the Free Software Foundation; either version 2 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 General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
#
# The original `Config` design model is unproudly borrowed from
# the rough pypy's guys: http://codespeak.net/svn/pypy/dist/pypy/config/
# the whole pypy projet is under MIT licence
# ____________________________________________________________
from time import time
from tiramisu.error import RequirementRecursionError, PropertiesOptionError
from tiramisu.i18n import _


expires_time = 5


class _const:
    """convenient class that emulates a module
    and builds constants (that is, unique names)"""
    class ConstError(TypeError):
        pass

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

    def __delattr__(self, name):
        if name in self.__dict__:
            raise self.ConstError, _("Can't unbind group ({})").format(name)
        raise ValueError(name)


# ____________________________________________________________
class GroupModule(_const):
    "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
# setting.groups (emulates a module)
groups = GroupModule()


def populate_groups():
    "populates the available groups in the appropriate namespaces"
    groups.master = groups.MasterGroupType('master')
    groups.default = groups.DefaultGroupType('default')
    groups.family = groups.GroupType('family')

# names are in the module now
populate_groups()


# ____________________________________________________________
class OwnerModule(_const):
    """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
# setting.owners (emulates a module)
owners = OwnerModule()


def populate_owners():
    """populates the available owners in the appropriate namespaces

    - 'user' is the generic is the generic owner.
    - 'default' is the config owner after init time
    """
    setattr(owners, 'default', owners.DefaultOwner('default'))
    setattr(owners, 'user', owners.Owner('user'))

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

# names are in the module now
populate_owners()


class MultiTypeModule(_const):
    class MultiType(str):
        pass

    class DefaultMultiType(MultiType):
        pass

    class MasterMultiType(MultiType):
        pass

    class SlaveMultiType(MultiType):
        pass

multitypes = MultiTypeModule()


def populate_multitypes():
    setattr(multitypes, 'default', multitypes.DefaultMultiType('default'))
    setattr(multitypes, 'master', multitypes.MasterMultiType('master'))
    setattr(multitypes, 'slave', multitypes.SlaveMultiType('slave'))

populate_multitypes()


class Property(object):
    __slots__ = ('_setting', '_properties', '_opt')

    def __init__(self, setting, prop, opt=None):
        self._opt = opt
        self._setting = setting
        self._properties = prop

    def append(self, propname):
        if not propname in self._properties:
            self._properties.append(propname)
            self._setting._set_properties(self._properties, self._opt)
        self._setting.context.cfgimpl_reset_cache()

    def remove(self, propname):
        if propname in self._properties:
            self._properties.remove(propname)
            self._setting._set_properties(self._properties, self._opt)
        self._setting.context.cfgimpl_reset_cache()

    def __contains__(self, propname):
        return propname in self._properties


#____________________________________________________________
class Setting(object):
    "``Config()``'s configuration options"
    __slots__ = ('context', '_properties', '_permissives', '_owner', '_cache')

    def __init__(self, context):
        # properties attribute: the name of a property enables this property
        # key is None for global properties
        self._properties = {None: ['expire']}
        # permissive properties
        self._permissives = {}
        # generic owner
        self._owner = owners.user
        self.context = context
        self._cache = {}

    #____________________________________________________________
    # properties methods
    def __contains__(self, propname):
        return propname in self._get_properties()

    def __getitem__(self, opt):
        return Property(self, self._get_properties(opt), opt)

    def __setitem__(self, opt, value):
        raise ValueError('you must only append/remove properties')

    def _get_properties(self, opt=None, is_apply_req=True):
        if opt is not None and opt in self._cache:
            exp = time()
            props, created = self._cache[opt]
            if exp < created:
                return props
        if opt is None:
            default = []
        else:
            if is_apply_req:
                apply_requires(opt, self.context)
            default = list(opt._properties)
        props = self._properties.get(opt, default)
        if opt is not None:
            self._set_cache(opt, props)
        return props

    def append(self, propname):
        "puts property propname in the Config's properties attribute"
        Property(self, self._get_properties()).append(propname)

    def remove(self, propname):
        "deletes property propname in the Config's properties attribute"
        Property(self, self._get_properties()).remove(propname)

    def _set_properties(self, properties, opt=None):
        """save properties for specified opt
        (never save properties if same has option properties)
        """
        if opt is None:
            self._properties[opt] = properties
        else:
            if opt._properties == properties:
                if opt in self._properties:
                    del(self._properties[opt])
            else:
                self._properties[opt] = properties

    def _validate_frozen(self, opt, value, is_write):
        if not is_write:
            return False
        if 'permissive' in self and 'frozen' in self._get_permissive():
            return False
        if 'everything_frozen' in self or (
                'frozen' in self and 'frozen' in self[opt]):
            return True
        return False

    def _validate_mandatory(self, opt, value, force_properties):
        if 'permissive' in self and 'mandatory' in self._get_permissive():
            return False
        check_mandatory = 'mandatory' in self
        if force_properties is not None:
            check_mandatory = ('mandatory' in force_properties or
                               check_mandatory)
        if check_mandatory and 'mandatory' in self[opt] and \
                self.context.cfgimpl_get_values()._is_empty(opt, value):
            return True
        return False

    def _calc_properties(self, opt_or_descr, force_permissive, force_properties):
        properties = set(self._get_properties(opt_or_descr))
        #remove this properties, those properties are validate in after
        properties = properties - set(['mandatory', 'frozen'])
        set_properties = set(self._get_properties())
        if force_properties is not None:
            set_properties.update(set(force_properties))
        properties = properties & set_properties
        if force_permissive is True or 'permissive' in self:
            properties = properties - set(self._get_permissive())
        properties = properties - set(self._get_permissive(opt_or_descr))
        return list(properties)

    #____________________________________________________________
    def validate_properties(self, opt_or_descr, is_descr, is_write,
                            value=None, force_permissive=False,
                            force_properties=None):
        properties = self._calc_properties(opt_or_descr, force_permissive,
                                           force_properties)
        raise_text = _("trying to access"
                       " to an option named: {0} with properties"
                       " {1}")
        if not is_descr:
            if self._validate_mandatory(opt_or_descr, value, force_properties):
                properties.append('mandatory')
            if self._validate_frozen(opt_or_descr, value, is_write):
                properties.append('frozen')
                raise_text = _('cannot change the value to {0} for '
                               'option {1} this option is frozen')
        if properties != []:
            raise PropertiesOptionError(raise_text.format(opt_or_descr._name,
                                                          str(properties)),
                                        properties)

    def _get_permissive(self, opt=None):
        return self._permissives.get(opt, [])

    def set_permissive(self, permissive, opt=None):
        if not isinstance(permissive, tuple):
            raise TypeError(_('permissive must be a tuple'))
        self._permissives[opt] = permissive

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

    def getowner(self):
        return self._owner

    #____________________________________________________________
    def read_only(self):
        "convenience method to freeze, hidde and disable"
        self.append('everything_frozen')
        self.append('frozen')  # can be usefull...
        self.remove('hidden')
        self.append('disabled')
        self.append('mandatory')
        self.append('validator')
        self.remove('permissive')

    def read_write(self):
        "convenience method to freeze, hidde and disable"
        self.remove('everything_frozen')
        self.append('frozen')  # can be usefull...
        self.append('hidden')
        self.append('disabled')
        self.remove('mandatory')
        self.append('validator')
        self.remove('permissive')

    def _set_cache(self, opt, props):
        if 'expire' in self:
            self._cache[opt] = (props, time() + expires_time)
            pass

    def reset_cache(self, only_expired):
        if only_expired:
            exp = time()
            keys = self._cache.keys()
            for key in keys:
                props, created = self._cache[key]
                if exp > created:
                    del(self._cache[key])
        else:
            self._cache.clear()


def apply_requires(opt, config):
    "carries out the jit (just in time requirements between options"
    def build_actions(requires):
        "action are hide, show, enable, disable..."
        trigger_actions = {}
        for require in requires:
            action = require[2]
            trigger_actions.setdefault(action, []).append(require)
        return trigger_actions
    #for symlink
    if hasattr(opt, '_requires') and opt._requires is not None:
        # filters the callbacks
        settings = config.cfgimpl_get_settings()
        setting = Property(settings, settings._get_properties(opt, False), opt)
        trigger_actions = build_actions(opt._requires)
        optpath = config.cfgimpl_get_context().cfgimpl_get_description().get_path_by_opt(opt)
        for requires in trigger_actions.values():
            matches = False
            for require in requires:
                if len(require) == 3:
                    path, expected, action = require
                    inverse = False
                elif len(require) == 4:
                    path, expected, action, inverse = require
                if path == optpath or path.startswith(optpath + '.'):
                    raise RequirementRecursionError(_("malformed requirements "
                                                    "imbrication detected for option: '{0}' "
                                                    "with requirement on: '{1}'").format(optpath, path))
                try:
                    value = config.cfgimpl_get_context()._getattr(path, force_permissive=True)
                except PropertiesOptionError, err:
                    properties = err.proptype
                    raise PropertiesOptionError(_("option '{0}' has requirement's property error: "
                                                  "{1} {2}").format(opt._name, path, properties))
                except AttributeError:
                    raise AttributeError(_("required option not found: "
                                         "{0}").format(path))
                if value == expected:
                    if inverse:
                        setting.remove(action)
                    else:
                        setting.append(action)
                    matches = True
            # no requirement has been triggered, then just reverse the action
            if not matches:
                if inverse:
                    setting.append(action)
                else:
                    setting.remove(action)