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 copy import copy
from tiramisu.error import RequirementError, PropertiesOptionError
from tiramisu.i18n import _

default_encoding = 'utf-8'

expires_time = 5
ro_remove = ('permissive', 'hidden')
ro_append = ('frozen', 'disabled', 'validator', 'everything_frozen', 'mandatory')
rw_remove = ('permissive', 'everything_frozen', 'mandatory')
rw_append = ('frozen', 'disabled', 'validator', 'hidden')
default_properties = set(('expire', 'validator'))

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):
    "namespace for the master/slaves"
    class MultiType(str):
        pass

    class DefaultMultiType(MultiType):
        pass

    class MasterMultiType(MultiType):
        pass

    class SlaveMultiType(MultiType):
        pass

multitypes = MultiTypeModule()


def populate_multitypes():
    "populates the master/slave namespace"
    setattr(multitypes, 'default', multitypes.DefaultMultiType('default'))
    setattr(multitypes, 'master', multitypes.MasterMultiType('master'))
    setattr(multitypes, 'slave', multitypes.SlaveMultiType('slave'))

populate_multitypes()


class Property(object):
    "a property is responsible of the option's value access rules"
    __slots__ = ('_setting', '_properties', '_opt')

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

    def append(self, propname):
        self._properties.add(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

    def __repr__(self):
        return str(list(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 = {}
        # 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 __repr__(self):
        return str(list(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 reset(self):
        try:
            del(self._properties[None])
        except KeyError:
            pass
        self.context.cfgimpl_reset_cache()

    def _get_properties(self, opt=None, is_apply_req=True):
        if opt is None:
            props = self._properties.get(opt, copy(default_properties))
        else:
            exp = None
            if opt in self._cache:
                exp = time()
                props, created = self._cache[opt]
                if exp < created:
                    return props
            if is_apply_req:
                self.apply_requires(opt)
            props = self._properties.get(opt, opt._properties)
            self._set_cache(opt, props, exp)
        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_properties(self, opt_or_descr, is_descr, is_write,
                            value=None, force_permissive=False,
                            force_properties=None):
        #opt properties
        properties = copy(self._get_properties(opt_or_descr))
        #remove opt permissive
        properties -= self._get_permissive(opt_or_descr)
        #remove global permissive if need
        self_properties = copy(self._get_properties())
        if force_permissive is True or 'permissive' in self_properties:
            properties -= self._get_permissive()

        #global properties
        if force_properties is not None:
            self_properties.update(force_properties)

        #calc properties
        properties &= self_properties
        #mandatory and frozen are special properties
        if is_descr:
            properties -= frozenset(('mandatory', 'frozen'))
        else:
            if 'mandatory' in properties and \
                    not self.context.cfgimpl_get_values()._is_empty(opt_or_descr,
                                                                    value):
                properties.remove('mandatory')
            if is_write and 'everything_frozen' in self_properties:
                properties.add('frozen')
            elif 'frozen' in properties and not is_write:
                properties.remove('frozen')

        if properties != frozenset():
            if 'frozen' in properties:
                raise_text = 'cannot change the value for option {0} this option is frozen'
            else:
                raise_text = "trying to access to an option named: {0} with properties {1}"
            raise PropertiesOptionError(_(raise_text).format(opt_or_descr._name,
                                        str(list(properties))),
                                        list(properties))

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

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

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

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

    def _set_cache(self, opt, props, exp):
        if 'expire' in self:
            if exp is None:
                exp = time()
            self._cache[opt] = (props, time() + expires_time)

    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(self, opt):
        "carries out the jit (just in time requirements between options"
        if opt._requires is None:
            return

        # filters the callbacks
        setting = Property(self, self._get_properties(opt, False), opt)
        descr = self.context.cfgimpl_get_description()
        optpath = descr.impl_get_path_by_opt(opt)
        for requires in opt._requires:
            matches = False
            for require in requires:
                option, expected, action, inverse, transitive, same_action = require
                path = descr.impl_get_path_by_opt(option)
                if path == optpath or path.startswith(optpath + '.'):
                    raise RequirementError(_("malformed requirements "
                                             "imbrication detected for option: '{0}' "
                                             "with requirement on: '{1}'").format(optpath, path))
                try:
                    value = self.context._getattr(path, force_permissive=True)
                except PropertiesOptionError, err:
                    if not transitive:
                        continue
                    properties = err.proptype
                    if same_action and action not in properties:
                        raise RequirementError(_("option '{0}' has requirement's property error: "
                                                 "{1} {2}").format(opt._name, path, properties))
                    #transitive action, force expected
                    value = expected[0]
                    inverse = False
                except AttributeError:
                    raise AttributeError(_("required option not found: "
                                           "{0}").format(path))
                if not inverse and value in expected or inverse and value not in expected:
                    matches = True
                    setting.append(action)
                    ## the calculation cannot be carried out
                    break
            # no requirement has been triggered, then just reverse the action
            if not matches:
                setting.remove(action)