Merge branch 'master' of ssh://git.labs.libre-entreprise.org/gitroot/tiramisu
[tiramisu.git] / tiramisu / setting.py
index 9a9c63a..86f900e 100644 (file)
 # ____________________________________________________________
 from time import time
 from copy import copy
-from tiramisu.error import RequirementError, PropertiesOptionError
+import weakref
+from tiramisu.error import (RequirementError, PropertiesOptionError,
+                            ConstError, ConfigError)
 from tiramisu.i18n import _
 
 
+default_encoding = 'utf-8'
 expires_time = 5
 ro_remove = ('permissive', 'hidden')
-ro_append = ('frozen', 'disabled', 'validator', 'everything_frozen', 'mandatory')
+ro_append = ('frozen', 'disabled', 'validator', 'everything_frozen',
+             'mandatory')
 rw_remove = ('permissive', 'everything_frozen', 'mandatory')
 rw_append = ('frozen', 'disabled', 'validator', 'hidden')
+default_properties = ('expire', 'validator')
 
 
-class _const:
+class StorageType:
+    default_storage = 'dictionary'
+    storage_type = None
+
+    def set_storage(self, name):
+        if self.storage_type is not None:
+            raise ConfigError(_('storage_type is already set, cannot rebind it'))
+        self.storage_type = name
+
+    def get_storage(self):
+        if self.storage_type is None:
+            self.storage_type = self.default_storage
+        storage = self.storage_type
+        return 'tiramisu.storage.{0}.storage'.format(
+            storage)
+
+
+storage_type = StorageType()
+
+
+class _NameSpace:
     """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)
+            raise ConstError(_("can't rebind {0}").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 ConstError(_("can't unbind {0}").format(name))
         raise ValueError(name)
 
 
 # ____________________________________________________________
-class GroupModule(_const):
+class GroupModule(_NameSpace):
     "emulates a module to manage unique group (OptionDescription) names"
     class GroupType(str):
         """allowed normal group (OptionDescription) names
@@ -83,7 +106,7 @@ populate_groups()
 
 
 # ____________________________________________________________
-class OwnerModule(_const):
+class OwnerModule(_NameSpace):
     """emulates a module to manage unique owner names.
 
     owners are living in `Config._cfgimpl_value_owners`
@@ -109,18 +132,18 @@ def populate_owners():
     setattr(owners, 'default', owners.DefaultOwner('default'))
     setattr(owners, 'user', owners.Owner('user'))
 
-    def add_owner(name):
+    def addowner(name):
         """
         :param name: the name of the new owner
         """
         setattr(owners, name, owners.Owner(name))
-    setattr(owners, 'add_owner', add_owner)
+    setattr(owners, 'addowner', addowner)
 
 # names are in the module now
 populate_owners()
 
 
-class MultiTypeModule(_const):
+class MultiTypeModule(_NameSpace):
     "namespace for the master/slaves"
     class MultiType(str):
         pass
@@ -148,23 +171,30 @@ populate_multitypes()
 
 class Property(object):
     "a property is responsible of the option's value access rules"
-    __slots__ = ('_setting', '_properties', '_opt')
+    __slots__ = ('_setting', '_properties', '_opt', '_path')
 
-    def __init__(self, setting, prop, opt=None):
+    def __init__(self, setting, prop, opt=None, path=None):
         self._opt = opt
+        self._path = path
         self._setting = setting
         self._properties = prop
 
     def append(self, propname):
+        if self._opt is not None and self._opt._calc_properties is not None \
+                and propname in self._opt._calc_properties:
+            raise ValueError(_('cannot append {0} property for option {1}: '
+                               'this property is calculated').format(
+                                   propname, self._opt._name))
         self._properties.add(propname)
-        self._setting._set_properties(self._properties, self._opt)
-        self._setting.context.cfgimpl_reset_cache()
+        self._setting._setproperties(self._properties, self._opt, self._path)
 
     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()
+            self._setting._setproperties(self._properties, self._opt, self._path)
+
+    def reset(self):
+        self._setting.reset(_path=self._path)
 
     def __contains__(self, propname):
         return propname in self._properties
@@ -173,121 +203,206 @@ class Property(object):
         return str(list(self._properties))
 
 
+def set_storage(name, **args):
+    storage_type.set_storage(name)
+    settings = __import__(storage_type.get_storage(), globals(), locals(),
+                          ['Setting'], -1).Setting()
+    for option, value in args.items():
+        try:
+            getattr(settings, option)
+            setattr(settings, option, value)
+        except AttributeError:
+            raise ValueError(_('option {0} not already exists in storage {1}'
+                               '').format(option, name))
+
+
+def get_storage(context, session_id, persistent):
+    def gen_id(config):
+        return str(id(config)) + str(time())
+
+    if session_id is None:
+        session_id = gen_id(context)
+    return __import__(storage_type.get_storage(), globals(), locals(),
+                      ['Storage'], -1).Storage(session_id, persistent)
+
+
+def list_sessions():
+    return __import__(storage_type.get_storage(), globals(), locals(),
+                      ['list_sessions'], -1).list_sessions()
+
+
+def delete_session(session_id):
+    return __import__(storage_type.get_storage(), globals(), locals(),
+                      ['delete_session'], -1).delete_session(session_id)
+
+
 #____________________________________________________________
-class Setting(object):
+class Settings(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: set(('expire', 'validator'))}
-        # permissive properties
-        self._permissives = {}
+    __slots__ = ('context', '_owner', '_p_', '__weakref__')
+
+    def __init__(self, context, storage):
+        """
+        initializer
+
+        :param context: the root config
+        :param storage: the storage type
+
+                        - dictionary -> in memory
+                        - sqlite3 -> persistent
+        """
         # generic owner
         self._owner = owners.user
-        self.context = context
-        self._cache = {}
+        self.context = weakref.ref(context)
+        import_lib = 'tiramisu.storage.{0}.setting'.format(storage.storage)
+        self._p_ = __import__(import_lib, globals(), locals(), ['Settings'],
+                              -1).Settings(storage)
 
     #____________________________________________________________
     # properties methods
     def __contains__(self, propname):
-        return propname in self._get_properties()
+        "enables the pythonic 'in' syntaxic sugar"
+        return propname in self._getproperties()
 
     def __repr__(self):
-        return str(list(self._get_properties()))
+        return str(list(self._getproperties()))
 
     def __getitem__(self, opt):
-        return Property(self, self._get_properties(opt), opt)
+        path = self._get_opt_path(opt)
+        return self._getitem(opt, path)
+
+    def _getitem(self, opt, path):
+        return Property(self, self._getproperties(opt, path), opt, path)
 
     def __setitem__(self, opt, value):
-        raise ValueError('you must only append/remove properties')
+        raise ValueError('you should only append/remove properties')
+
+    def reset(self, opt=None, _path=None, all_properties=False):
+        if all_properties and (_path or opt):
+            raise ValueError(_('opt and all_properties must not be set '
+                               'together in reset'))
+        if all_properties:
+            self._p_.reset_all_propertives()
+        else:
+            if opt is not None and _path is None:
+                _path = self._get_opt_path(opt)
+            self._p_.reset_properties(_path)
+        self.context().cfgimpl_reset_cache()
 
-    def _get_properties(self, opt=None, is_apply_req=True):
+    def _getproperties(self, opt=None, path=None, is_apply_req=True):
         if opt is None:
-            props = self._properties.get(opt, set())
+            props = self._p_.getproperties(path, default_properties)
         else:
-            exp = None
-            if opt in self._cache:
-                exp = time()
-                props, created = self._cache[opt]
-                if exp < created:
+            if path is None:
+                raise ValueError(_('if opt is not None, path should not be'
+                                   ' None in _getproperties'))
+            ntime = None
+            if self._p_.hascache('property', path):
+                ntime = time()
+                is_cached, props = self._p_.getcache('property', path, ntime)
+                if is_cached:
                     return props
+            props = self._p_.getproperties(path, opt._properties)
             if is_apply_req:
-                apply_requires(opt, self.context)
-            props = self._properties.get(opt, opt._properties)
-            self._set_cache(opt, props, exp)
+                props |= self.apply_requires(opt, path)
+            if 'expire' in self:
+                if ntime is None:
+                    ntime = time()
+                self._p_.setcache('property', path, props, ntime + expires_time)
         return props
 
     def append(self, propname):
         "puts property propname in the Config's properties attribute"
-        Property(self, self._get_properties()).append(propname)
+        props = self._p_.getproperties(None, default_properties)
+        props.add(propname)
+        self._setproperties(props, None, None)
 
     def remove(self, propname):
         "deletes property propname in the Config's properties attribute"
-        Property(self, self._get_properties()).remove(propname)
+        props = self._p_.getproperties(None, default_properties)
+        if propname in props:
+            props.remove(propname)
+            self._setproperties(props, None, None)
 
-    def _set_properties(self, properties, opt=None):
+    def _setproperties(self, properties, opt, path):
         """save properties for specified opt
         (never save properties if same has option properties)
         """
         if opt is None:
-            self._properties[opt] = properties
+            self._p_.setproperties(None, properties)
         else:
-            if opt._properties == properties:
-                if opt in self._properties:
-                    del(self._properties[opt])
+            if opt._calc_properties is not None:
+                properties -= opt._calc_properties
+            if set(opt._properties) == properties:
+                self._p_.reset_properties(path)
             else:
-                self._properties[opt] = properties
+                self._p_.setproperties(path, properties)
+        self.context().cfgimpl_reset_cache()
 
     #____________________________________________________________
-    def validate_properties(self, opt_or_descr, is_descr, is_write,
+    def validate_properties(self, opt_or_descr, is_descr, is_write, path,
                             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())
+        """
+        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
+        :param is_descr: we have to know if we are in an option description,
+                         just because the mandatory property
+                         doesn't exist here
+
+        :param is_write: in the validation process, an option is to be modified,
+                         the behavior can be different
+                         (typically with the `frozen` property)
+        """
+        # opt properties
+        properties = copy(self._getproperties(opt_or_descr, path))
+        # remove opt permissive
+        properties -= self._p_.getpermissive(path)
+        # remove global permissive if need
+        self_properties = copy(self._getproperties())
         if force_permissive is True or 'permissive' in self_properties:
-            properties -= self._get_permissive()
+            properties -= self._p_.getpermissive()
 
-        #global properties
+        # global properties
         if force_properties is not None:
             self_properties.update(force_properties)
 
-        #calc properties
+        # calc properties
         properties &= self_properties
-        #mandatory and frozen are special 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):
+                    not self.context().cfgimpl_get_values()._isempty(
+                        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')
-
+        # at this point an option should not remain in properties
         if properties != frozenset():
+            props = list(properties)
             if 'frozen' in properties:
-                raise_text = 'cannot change the value for option {0} this option is frozen'
+                raise PropertiesOptionError(_('cannot change the value for '
+                                              'option {0} this option is'
+                                              ' frozen').format(
+                                                  opt_or_descr._name),
+                                            props)
             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())
+                raise PropertiesOptionError(_("trying to access to an option "
+                                              "named: {0} with properties {1}"
+                                              "").format(opt_or_descr._name,
+                                                         str(props)), props)
 
-    def set_permissive(self, permissive, opt=None):
+    def setpermissive(self, permissive, path=None):
         if not isinstance(permissive, tuple):
             raise TypeError(_('permissive must be a tuple'))
-        self._permissives[opt] = frozenset(permissive)
+        self._p_.setpermissive(path, permissive)
 
     #____________________________________________________________
     def setowner(self, owner):
@@ -314,81 +429,94 @@ class Setting(object):
         "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])
+            self._p_.reset_expired_cache('property', time())
         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:
+            self._p_.reset_all_cache('property')
+
+    def apply_requires(self, opt, path):
+        """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 name or path
+
+        - **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 must be removed from 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
+        """
+        if opt._requires is None:
+            return frozenset()
+
         # filters the callbacks
-        settings = config.cfgimpl_get_settings()
-        setting = Property(settings, settings._get_properties(opt, False), opt)
-        trigger_actions = build_actions(opt._requires)
-        descr = config.cfgimpl_get_context().cfgimpl_get_description()
-        optpath = descr.impl_get_path_by_opt(opt)
-        for requires in trigger_actions.values():
-            matches = False
+        calc_properties = set()
+        for requires in opt._requires:
             for require in requires:
-                if len(require) == 3:
-                    option, expected, action = require
-                    inverse = False
-                    transitive = True
-                elif len(require) == 4:
-                    option, expected, action, inverse = require
-                    transitive = True
-                elif len(require) == 5:
-                    option, expected, action, inverse, transitive = require
-                path = descr.impl_get_path_by_opt(option)
-                if path == optpath or path.startswith(optpath + '.'):
+                option, expected, action, inverse, \
+                    transitive, same_action = require
+                reqpath = self._get_opt_path(option)
+                if reqpath == path or reqpath.startswith(path + '.'):
                     raise RequirementError(_("malformed requirements "
-                                             "imbrication detected for option: '{0}' "
-                                             "with requirement on: '{1}'").format(optpath, path))
+                                             "imbrication detected for option:"
+                                             " '{0}' with requirement on: "
+                                             "'{1}'").format(path, reqpath))
                 try:
-                    value = config.cfgimpl_get_context()._getattr(path, force_permissive=True)
+                    value = self.context()._getattr(reqpath,
+                                                    force_permissive=True)
                 except PropertiesOptionError, err:
                     if not transitive:
                         continue
                     properties = err.proptype
-                    if action not in err.proptype:
-                        raise RequirementError(_("option '{0}' has requirement's property error: "
-                                                 "{1} {2}").format(opt._name, path, properties), properties)
-                    #transitive action, force expected
-                    value = expected
-                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)
+                    if same_action and action not in properties:
+                        raise RequirementError(_("option '{0}' has "
+                                                 "requirement's property "
+                                                 "error: "
+                                                 "{1} {2}").format(opt._name,
+                                                                   reqpath,
+                                                                   properties))
+                    # transitive action, force expected
+                    value = expected[0]
+                    inverse = False
+                if (not inverse and
+                        value in expected or
+                        inverse and value not in expected):
+                    calc_properties.add(action)
+                    # the calculation cannot be carried out
+                    break
+            return calc_properties
+
+    def _get_opt_path(self, opt):
+        return self.context().cfgimpl_get_description().impl_get_path_by_opt(opt)