tiramisu/config.py

   1 # -*- coding: utf-8 -*-
   2 # Copyright (C) 2012-2013 Team tiramisu (see AUTHORS for all contributors)
   3 #
   4 # This program is free software; you can redistribute it and/or modify
   5 # it under the terms of the GNU General Public License as published by
   6 # the Free Software Foundation; either version 2 of the License, or
   7 # (at your option) any later version.
   8 #
   9 # This program is distributed in the hope that it will be useful,
  10 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 # GNU General Public License for more details.
  13 #
  14 # You should have received a copy of the GNU General Public License
  15 # along with this program; if not, write to the Free Software
  16 # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  17 #
  18 # The original `Config` design model is unproudly borrowed from
  19 # the rough pypy's guys: http://codespeak.net/svn/pypy/dist/pypy/config/
  20 # the whole pypy projet is under MIT licence
  21 # ____________________________________________________________
  22 "options handler global entry point"
  23 import weakref
  24 from tiramisu.error import PropertiesOptionError, ConfigError
  25 from tiramisu.option import OptionDescription, Option, SymLinkOption
  26 from tiramisu.setting import groups, Settings, default_encoding
  27 from tiramisu.storage import get_storages, get_storage, set_storage, \
  28     _impl_getstate_setting
  29 from tiramisu.value import Values, Multi
  30 from tiramisu.i18n import _
  31
  32
  33 class SubConfig(object):
  34     """Sub configuration management entry.
  35     Tree if OptionDescription's responsability. SubConfig are generated
  36     on-demand. A Config is also a SubConfig.
  37     Root Config is call context below
  38     """
  39     __slots__ = ('_impl_context', '_impl_descr', '_impl_path')
  40
  41     def __init__(self, descr, context, subpath=None):
  42         """ Configuration option management master class
  43
  44         :param descr: describes the configuration schema
  45         :type descr: an instance of ``option.OptionDescription``
  46         :param context: the current root config
  47         :type context: `Config`
  48         :type subpath: `str` with the path name
  49         """
  50         # main option description
  51         if descr is not None and not isinstance(descr, OptionDescription):
  52             raise TypeError(_('descr must be an optiondescription, not {0}'
  53                               ).format(type(descr)))
  54         self._impl_descr = descr
  55         # sub option descriptions
  56         if not isinstance(context, weakref.ReferenceType):
  57             raise ValueError('context must be a Weakref')
  58         self._impl_context = context
  59         self._impl_path = subpath
  60
  61     def cfgimpl_reset_cache(self, only_expired=False, only=('values',
  62                                                             'settings')):
  63         "remove cache (in context)"
  64         self._cfgimpl_get_context().cfgimpl_reset_cache(only_expired, only)
  65
  66     def cfgimpl_get_home_by_path(self, path, force_permissive=False,
  67                                  force_properties=None):
  68         """:returns: tuple (config, name)"""
  69         path = path.split('.')
  70         for step in path[:-1]:
  71             self = self._getattr(step,
  72                                  force_permissive=force_permissive,
  73                                  force_properties=force_properties)
  74         return self, path[-1]
  75
  76     def __hash__(self):
  77         return hash(self.cfgimpl_get_description().impl_getkey(self))
  78
  79     def __eq__(self, other):
  80         "Config's comparison"
  81         if not isinstance(other, Config):
  82             return False
  83         return self.cfgimpl_get_description().impl_getkey(self) == \
  84             other.cfgimpl_get_description().impl_getkey(other)
  85
  86     def __ne__(self, other):
  87         "Config's comparison"
  88         if not isinstance(other, Config):
  89             return True
  90         return not self == other
  91
  92     # ______________________________________________________________________
  93     def __iter__(self):
  94         """Pythonesque way of parsing group's ordered options.
  95         iteration only on Options (not OptionDescriptions)"""
  96         for child in self.cfgimpl_get_description().impl_getchildren():
  97             if not isinstance(child, OptionDescription):
  98                 try:
  99                     yield child._name, getattr(self, child._name)
 100                 except GeneratorExit:
 101                     raise StopIteration
 102                 except PropertiesOptionError:
 103                     pass  # option with properties
 104
 105     def iter_all(self):
 106         """A way of parsing options **and** groups.
 107         iteration on Options and OptionDescriptions."""
 108         for child in self.cfgimpl_get_description().impl_getchildren():
 109             try:
 110                 yield child._name, getattr(self, child._name)
 111             except GeneratorExit:
 112                 raise StopIteration
 113             except PropertiesOptionError:
 114                 pass  # option with properties
 115
 116     def iter_groups(self, group_type=None):
 117         """iteration on groups objects only.
 118         All groups are returned if `group_type` is `None`, otherwise the groups
 119         can be filtered by categories (families, or whatever).
 120
 121         :param group_type: if defined, is an instance of `groups.GroupType`
 122                            or `groups.MasterGroupType` that lives in
 123                            `setting.groups`
 124         """
 125         if group_type is not None and not isinstance(group_type,
 126                                                      groups.GroupType):
 127             raise TypeError(_("unknown group_type: {0}").format(group_type))
 128         for child in self.cfgimpl_get_description().impl_getchildren():
 129             if isinstance(child, OptionDescription):
 130                 try:
 131                     if group_type is None or (group_type is not None and
 132                                               child.impl_get_group_type()
 133                                               == group_type):
 134                         yield child._name, getattr(self, child._name)
 135                 except GeneratorExit:
 136                     raise StopIteration
 137                 except PropertiesOptionError:
 138                     pass
 139     # ______________________________________________________________________
 140
 141     def __str__(self):
 142         "Config's string representation"
 143         lines = []
 144         for name, grp in self.iter_groups():
 145             lines.append("[{0}]".format(name))
 146         for name, value in self:
 147             try:
 148                 lines.append("{0} = {1}".format(name, value))
 149             except UnicodeEncodeError:
 150                 lines.append("{0} = {1}".format(name,
 151                                                 value.encode(default_encoding)))
 152             except PropertiesOptionError:
 153                 pass
 154         return '\n'.join(lines)
 155
 156     __repr__ = __str__
 157
 158     def _cfgimpl_get_context(self):
 159         """context could be None, we need to test it
 160         context is None only if all reference to `Config` object is deleted
 161         (for example we delete a `Config` and we manipulate a reference to
 162         old `SubConfig`, `Values`, `Multi` or `Settings`)
 163         """
 164         context = self._impl_context()
 165         if context is None:
 166             raise ConfigError(_('the context does not exist anymore'))
 167         return context
 168
 169     def cfgimpl_get_description(self):
 170         if self._impl_descr is None:
 171             raise ConfigError(_('no option description found for this config'
 172                                 ' (may be GroupConfig)'))
 173         else:
 174             return self._impl_descr
 175
 176     def cfgimpl_get_settings(self):
 177         return self._cfgimpl_get_context()._impl_settings
 178
 179     def cfgimpl_get_values(self):
 180         return self._cfgimpl_get_context()._impl_values
 181
 182     # ____________________________________________________________
 183     # attribute methods
 184     def __setattr__(self, name, value):
 185         "attribute notation mechanism for the setting of the value of an option"
 186         if name.startswith('_impl_'):
 187             object.__setattr__(self, name, value)
 188             return
 189         self._setattr(name, value)
 190
 191     def _setattr(self, name, value, force_permissive=False):
 192         if '.' in name:
 193             homeconfig, name = self.cfgimpl_get_home_by_path(name)
 194             return homeconfig.__setattr__(name, value)
 195         child = getattr(self.cfgimpl_get_description(), name)
 196         if isinstance(child, OptionDescription):
 197             raise TypeError(_("can't assign to an OptionDescription"))
 198         elif not isinstance(child, SymLinkOption):
 199             if self._impl_path is None:
 200                 path = name
 201             else:
 202                 path = self._impl_path + '.' + name
 203             self.cfgimpl_get_values().setitem(child, value, path,
 204                                               force_permissive=force_permissive)
 205         else:
 206             context = self._cfgimpl_get_context()
 207             path = context.cfgimpl_get_description().impl_get_path_by_opt(
 208                 child._opt)
 209             context._setattr(path, value, force_permissive=force_permissive)
 210
 211     def __delattr__(self, name):
 212         child = getattr(self.cfgimpl_get_description(), name)
 213         self.cfgimpl_get_values().__delitem__(child)
 214
 215     def __getattr__(self, name):
 216         return self._getattr(name)
 217
 218     def _getattr(self, name, force_permissive=False, force_properties=None,
 219                  validate=True):
 220         """
 221         attribute notation mechanism for accessing the value of an option
 222         :param name: attribute name
 223         :return: option's value if name is an option name, OptionDescription
 224                  otherwise
 225         """
 226         # attribute access by passing a path,
 227         # for instance getattr(self, "creole.general.family.adresse_ip_eth0")
 228         if '.' in name:
 229             homeconfig, name = self.cfgimpl_get_home_by_path(
 230                 name, force_permissive=force_permissive,
 231                 force_properties=force_properties)
 232             return homeconfig._getattr(name, force_permissive=force_permissive,
 233                                        force_properties=force_properties,
 234                                        validate=validate)
 235         opt_or_descr = getattr(self.cfgimpl_get_description(), name)
 236         if self._impl_path is None:
 237             subpath = name
 238         else:
 239             subpath = self._impl_path + '.' + name
 240         # symlink options
 241         if isinstance(opt_or_descr, SymLinkOption):
 242             context = self._cfgimpl_get_context()
 243             path = context.cfgimpl_get_description().impl_get_path_by_opt(
 244                 opt_or_descr._opt)
 245             return context._getattr(path, validate=validate,
 246                                     force_properties=force_properties,
 247                                     force_permissive=force_permissive)
 248         elif isinstance(opt_or_descr, OptionDescription):
 249             self.cfgimpl_get_settings().validate_properties(
 250                 opt_or_descr, True, False, path=subpath,
 251                 force_permissive=force_permissive,
 252                 force_properties=force_properties)
 253             return SubConfig(opt_or_descr, self._impl_context, subpath)
 254         else:
 255             return self.cfgimpl_get_values().getitem(
 256                 opt_or_descr, path=subpath,
 257                 validate=validate,
 258                 force_properties=force_properties,
 259                 force_permissive=force_permissive)
 260
 261     def find(self, bytype=None, byname=None, byvalue=None, type_='option',
 262              check_properties=True):
 263         """
 264             finds a list of options recursively in the config
 265
 266             :param bytype: Option class (BoolOption, StrOption, ...)
 267             :param byname: filter by Option._name
 268             :param byvalue: filter by the option's value
 269             :returns: list of matching Option objects
 270         """
 271         return self._cfgimpl_get_context()._find(bytype, byname, byvalue,
 272                                                  first=False,
 273                                                  type_=type_,
 274                                                  _subpath=self.cfgimpl_get_path(),
 275                                                  check_properties=check_properties)
 276
 277     def find_first(self, bytype=None, byname=None, byvalue=None,
 278                    type_='option', display_error=True, check_properties=True):
 279         """
 280             finds an option recursively in the config
 281
 282             :param bytype: Option class (BoolOption, StrOption, ...)
 283             :param byname: filter by Option._name
 284             :param byvalue: filter by the option's value
 285             :returns: list of matching Option objects
 286         """
 287         return self._cfgimpl_get_context()._find(
 288             bytype, byname, byvalue, first=True, type_=type_,
 289             _subpath=self.cfgimpl_get_path(), display_error=display_error,
 290             check_properties=check_properties)
 291
 292     def _find(self, bytype, byname, byvalue, first, type_='option',
 293               _subpath=None, check_properties=True, display_error=True):
 294         """
 295         convenience method for finding an option that lives only in the subtree
 296
 297         :param first: return only one option if True, a list otherwise
 298         :return: find list or an exception if nothing has been found
 299         """
 300         def _filter_by_name():
 301             try:
 302                 if byname is None or path == byname or \
 303                         path.endswith('.' + byname):
 304                     return True
 305             except IndexError:
 306                 pass
 307             return False
 308
 309         def _filter_by_value():
 310             if byvalue is None:
 311                 return True
 312             try:
 313                 value = getattr(self, path)
 314                 if isinstance(value, Multi):
 315                     return byvalue in value
 316                 else:
 317                     return value == byvalue
 318             except PropertiesOptionError:  # a property is a restriction
 319                                            # upon the access of the value
 320                 return False
 321
 322         def _filter_by_type():
 323             if bytype is None:
 324                 return True
 325             if isinstance(option, bytype):
 326                 return True
 327             return False
 328
 329         if type_ not in ('option', 'path', 'value'):
 330             raise ValueError(_('unknown type_ type {0}'
 331                                'for _find').format(type_))
 332         find_results = []
 333         opts, paths = self.cfgimpl_get_description()._cache_paths
 334         for index in range(0, len(paths)):
 335             option = opts[index]
 336             if isinstance(option, OptionDescription):
 337                 continue
 338             path = paths[index]
 339             if _subpath is not None and not path.startswith(_subpath + '.'):
 340                 continue
 341             if not _filter_by_name():
 342                 continue
 343             if not _filter_by_value():
 344                 continue
 345             if not _filter_by_type():
 346                 continue
 347             #remove option with propertyerror, ...
 348             if byvalue is None and check_properties:
 349                 try:
 350                     value = getattr(self, path)
 351                 except PropertiesOptionError:
 352                     # a property restricts the access of the value
 353                     continue
 354             if type_ == 'value':
 355                 retval = value
 356             elif type_ == 'path':
 357                 retval = path
 358             elif type_ == 'option':
 359                 retval = option
 360             if first:
 361                 return retval
 362             else:
 363                 find_results.append(retval)
 364         return self._find_return_results(find_results, display_error)
 365
 366     def _find_return_results(self, find_results, display_error):
 367         if find_results == []:
 368             if display_error:
 369                 raise AttributeError(_("no option found in config"
 370                                        " with these criteria"))
 371             else:
 372                 # translation is slow
 373                 raise AttributeError()
 374         else:
 375             return find_results
 376
 377     def make_dict(self, flatten=False, _currpath=None, withoption=None,
 378                   withvalue=None):
 379         """exports the whole config into a `dict`, for example:
 380
 381         >>> print cfg.make_dict()
 382         {'od2.var4': None, 'od2.var5': None, 'od2.var6': None}
 383
 384
 385
 386         :param flatten: returns a dict(name=value) instead of a dict(path=value)
 387                         ::
 388
 389                             >>> print cfg.make_dict(flatten=True)
 390                             {'var5': None, 'var4': None, 'var6': None}
 391
 392         :param withoption: returns the options that are present in the very same
 393                            `OptionDescription` than the `withoption` itself::
 394
 395                                 >>> print cfg.make_dict(withoption='var1')
 396                                 {'od2.var4': None, 'od2.var5': None,
 397                                 'od2.var6': None,
 398                                 'od2.var1': u'value',
 399                                 'od1.var1': None,
 400                                 'od1.var3': None,
 401                                 'od1.var2': None}
 402
 403         :param withvalue: returns the options that have the value `withvalue`
 404                           ::
 405
 406                             >>> print c.make_dict(withoption='var1',
 407                                                   withvalue=u'value')
 408                             {'od2.var4': None,
 409                             'od2.var5': None,
 410                             'od2.var6': None,
 411                             'od2.var1': u'value'}
 412
 413         :returns: dict of Option's name (or path) and values
 414         """
 415         pathsvalues = []
 416         if _currpath is None:
 417             _currpath = []
 418         if withoption is None and withvalue is not None:
 419             raise ValueError(_("make_dict can't filtering with value without "
 420                                "option"))
 421         if withoption is not None:
 422             mypath = self.cfgimpl_get_path()
 423             for path in self._cfgimpl_get_context()._find(bytype=Option,
 424                                                           byname=withoption,
 425                                                           byvalue=withvalue,
 426                                                           first=False,
 427                                                           type_='path',
 428                                                           _subpath=mypath):
 429                 path = '.'.join(path.split('.')[:-1])
 430                 opt = self._cfgimpl_get_context().cfgimpl_get_description(
 431                 ).impl_get_opt_by_path(path)
 432                 if mypath is not None:
 433                     if mypath == path:
 434                         withoption = None
 435                         withvalue = None
 436                         break
 437                     else:
 438                         tmypath = mypath + '.'
 439                         if not path.startswith(tmypath):
 440                             raise AttributeError(_('unexpected path {0}, '
 441                                                    'should start with {1}'
 442                                                    '').format(path, mypath))
 443                         path = path[len(tmypath):]
 444                 self._make_sub_dict(opt, path, pathsvalues, _currpath, flatten)
 445         #withoption can be set to None below !
 446         if withoption is None:
 447             for opt in self.cfgimpl_get_description().impl_getchildren():
 448                 path = opt._name
 449                 self._make_sub_dict(opt, path, pathsvalues, _currpath, flatten)
 450         if _currpath == []:
 451             options = dict(pathsvalues)
 452             return options
 453         return pathsvalues
 454
 455     def _make_sub_dict(self, opt, path, pathsvalues, _currpath, flatten):
 456         if isinstance(opt, OptionDescription):
 457             try:
 458                 pathsvalues += getattr(self, path).make_dict(flatten,
 459                                                              _currpath +
 460                                                              path.split('.'))
 461             except PropertiesOptionError:
 462                 pass  # this just a hidden or disabled option
 463         else:
 464             try:
 465                 value = self._getattr(opt._name)
 466                 if flatten:
 467                     name = opt._name
 468                 else:
 469                     name = '.'.join(_currpath + [opt._name])
 470                 pathsvalues.append((name, value))
 471             except PropertiesOptionError:
 472                 pass  # this just a hidden or disabled option
 473
 474     def cfgimpl_get_path(self):
 475         descr = self.cfgimpl_get_description()
 476         context_descr = self._cfgimpl_get_context().cfgimpl_get_description()
 477         return context_descr.impl_get_path_by_opt(descr)
 478
 479
 480 class _CommonConfig(SubConfig):
 481     "abstract base class for the Config, GroupConfig and the MetaConfig"
 482     __slots__ = ('_impl_values', '_impl_settings', '_impl_meta', '_impl_test')
 483
 484     def _impl_build_all_paths(self):
 485         self.cfgimpl_get_description().impl_build_cache()
 486
 487     def read_only(self):
 488         "read only is a global config's setting, see `settings.py`"
 489         self.cfgimpl_get_settings().read_only()
 490
 491     def read_write(self):
 492         "read write is a global config's setting, see `settings.py`"
 493         self.cfgimpl_get_settings().read_write()
 494
 495     def getowner(self, opt):
 496         """convenience method to retrieve an option's owner
 497         from the config itself
 498         """
 499         if not isinstance(opt, Option) and not isinstance(opt, SymLinkOption):
 500             raise TypeError(_('opt in getowner must be an option not {0}'
 501                               '').format(type(opt)))
 502         return self.cfgimpl_get_values().getowner(opt)
 503
 504     def unwrap_from_path(self, path, force_permissive=False):
 505         """convenience method to extract and Option() object from the Config()
 506         and it is **fast**: finds the option directly in the appropriate
 507         namespace
 508
 509         :returns: Option()
 510         """
 511         if '.' in path:
 512             homeconfig, path = self.cfgimpl_get_home_by_path(
 513                 path, force_permissive=force_permissive)
 514             return getattr(homeconfig.cfgimpl_get_description(), path)
 515         return getattr(self.cfgimpl_get_description(), path)
 516
 517     def cfgimpl_get_path(self):
 518         return None
 519
 520     def cfgimpl_get_meta(self):
 521         if self._impl_meta is not None:
 522             return self._impl_meta()
 523
 524     # information
 525     def impl_set_information(self, key, value):
 526         """updates the information's attribute
 527
 528         :param key: information's key (ex: "help", "doc"
 529         :param value: information's value (ex: "the help string")
 530         """
 531         self._impl_values.set_information(key, value)
 532
 533     def impl_get_information(self, key, default=None):
 534         """retrieves one information's item
 535
 536         :param key: the item string (ex: "help")
 537         """
 538         return self._impl_values.get_information(key, default)
 539
 540     # ----- state
 541     def __getstate__(self):
 542         if self._impl_meta is not None:
 543             #FIXME _impl_meta est un weakref => faut pas sauvegarder mais faut bien savoir si c'est un méta ou pas au final ...
 544             #en fait il faut ne pouvoir sérialisé que depuis une MetaConfig ... et pas directement comme pour les options
 545             raise ConfigError('cannot serialize Config with MetaConfig')
 546         slots = set()
 547         for subclass in self.__class__.__mro__:
 548             if subclass is not object:
 549                 slots.update(subclass.__slots__)
 550         slots -= frozenset(['_impl_context', '_impl_meta', '__weakref__'])
 551         state = {}
 552         for slot in slots:
 553             try:
 554                 state[slot] = getattr(self, slot)
 555             except AttributeError:
 556                 pass
 557         storage = self._impl_values._p_._storage
 558         if not storage.serializable:
 559             raise ConfigError('this storage is not serialisable, could be a '
 560                               'none persistent storage')
 561         state['_storage'] = {'session_id': storage.session_id,
 562                              'persistent': storage.persistent}
 563         state['_impl_setting'] = _impl_getstate_setting()
 564         return state
 565
 566     def __setstate__(self, state):
 567         for key, value in state.items():
 568             if key not in ['_storage', '_impl_setting']:
 569                 setattr(self, key, value)
 570         set_storage(**state['_impl_setting'])
 571         self._impl_context = weakref.ref(self)
 572         self._impl_settings.context = weakref.ref(self)
 573         self._impl_values.context = weakref.ref(self)
 574         storage = get_storage(test=self._impl_test, **state['_storage'])
 575         self._impl_values._impl_setstate(storage)
 576         self._impl_settings._impl_setstate(storage)
 577         self._impl_meta = None
 578
 579
 580 # ____________________________________________________________
 581 class Config(_CommonConfig):
 582     "main configuration management entry"
 583     __slots__ = ('__weakref__',)
 584
 585     def __init__(self, descr, session_id=None, persistent=False):
 586         """ Configuration option management master class
 587
 588         :param descr: describes the configuration schema
 589         :type descr: an instance of ``option.OptionDescription``
 590         :param context: the current root config
 591         :type context: `Config`
 592         :param session_id: session ID is import with persistent Config to
 593         retrieve good session
 594         :type session_id: `str`
 595         :param persistent: if persistent, don't delete storage when leaving
 596         :type persistent: `boolean`
 597         """
 598         settings, values = get_storages(self, session_id, persistent)
 599         self._impl_settings = Settings(self, settings)
 600         self._impl_values = Values(self, values)
 601         super(Config, self).__init__(descr, weakref.ref(self))
 602         self._impl_build_all_paths()
 603         self._impl_meta = None
 604         #undocumented option used only in test script
 605         self._impl_test = False
 606
 607     def cfgimpl_reset_cache(self,
 608                             only_expired=False,
 609                             only=('values', 'settings')):
 610         if 'values' in only:
 611             self.cfgimpl_get_values().reset_cache(only_expired=only_expired)
 612         if 'settings' in only:
 613             self.cfgimpl_get_settings().reset_cache(only_expired=only_expired)
 614
 615
 616 class GroupConfig(_CommonConfig):
 617     __slots__ = ('_impl_children', '__weakref__')
 618
 619     def __init__(self, children, session_id=None, persistent=False,
 620                  _descr=None):
 621         if not isinstance(children, list):
 622             raise ValueError(_("metaconfig's children must be a list"))
 623         self._impl_children = children
 624         settings, values = get_storages(self, session_id, persistent)
 625         self._impl_settings = Settings(self, settings)
 626         self._impl_values = Values(self, values)
 627         super(GroupConfig, self).__init__(_descr, weakref.ref(self))
 628         self._impl_meta = None
 629         #undocumented option used only in test script
 630         self._impl_test = False
 631
 632     def cfgimpl_get_children(self):
 633         return self._impl_children
 634
 635     #def cfgimpl_get_context(self):
 636     #    "a meta config is a config which has a setting, that is itself"
 637     #    return self
 638     #
 639     def cfgimpl_reset_cache(self,
 640                             only_expired=False,
 641                             only=('values', 'settings')):
 642         if 'values' in only:
 643             self.cfgimpl_get_values().reset_cache(only_expired=only_expired)
 644         if 'settings' in only:
 645             self.cfgimpl_get_settings().reset_cache(only_expired=only_expired)
 646         for child in self._impl_children:
 647             child.cfgimpl_reset_cache(only_expired=only_expired, only=only)
 648
 649     def setattrs(self, path, value):
 650         """Setattr not in current GroupConfig, but in each children
 651         """
 652         for child in self._impl_children:
 653             try:
 654                 if not isinstance(child, GroupConfig):
 655                     setattr(child, path, value)
 656                 else:
 657                     child.setattrs(path, value)
 658             except PropertiesOptionError:
 659                 pass
 660
 661     def find_firsts(self, byname=None, bypath=None, byvalue=None,
 662                     type_='path', display_error=True):
 663         """Find first not in current GroupConfig, but in each children
 664         """
 665         ret = []
 666         #if MetaConfig, all children have same OptionDescription as context
 667         #so search only one time for all children
 668         try:
 669             if bypath is None and byname is not None and \
 670                     isinstance(self, MetaConfig):
 671                 bypath = self._find(bytype=None, byvalue=None, byname=byname,
 672                                     first=True, type_='path',
 673                                     check_properties=False,
 674                                     display_error=display_error)
 675                 byname = None
 676         except AttributeError:
 677             pass
 678         for child in self._impl_children:
 679             try:
 680                 if not isinstance(child, MetaConfig):
 681                     if bypath is not None:
 682                         #if byvalue is None, try if not raise
 683                         value = getattr(child, bypath)
 684                         if byvalue is not None:
 685                             if isinstance(value, Multi):
 686                                 if byvalue in value:
 687                                     ret.append(child)
 688                             else:
 689                                 if value == byvalue:
 690                                     ret.append(child)
 691                         else:
 692                             ret.append(child)
 693                     else:
 694                         ret.append(child.find_first(byname=byname,
 695                                                     byvalue=byvalue,
 696                                                     type_=type_,
 697                                                     display_error=False))
 698                 else:
 699                     ret.extend(child.find_firsts(byname=byname,
 700                                                  bypath=bypath,
 701                                                  byvalue=byvalue,
 702                                                  type_=type_,
 703                                                  display_error=False))
 704             except AttributeError:
 705                 pass
 706         return self._find_return_results(ret, display_error)
 707
 708
 709 class MetaConfig(GroupConfig):
 710     __slots__ = tuple()
 711
 712     def __init__(self, children, session_id=None, persistent=False):
 713         descr = None
 714         for child in children:
 715             if not isinstance(child, _CommonConfig):
 716                 raise TypeError(_("metaconfig's children "
 717                                   "should be config, not {0}"
 718                                   ).format(type(child)))
 719             if child.cfgimpl_get_meta() is not None:
 720                 raise ValueError(_("child has already a metaconfig's"))
 721             if descr is None:
 722                 descr = child.cfgimpl_get_description()
 723             elif not descr is child.cfgimpl_get_description():
 724                 raise ValueError(_('all config in metaconfig must '
 725                                    'have the same optiondescription'))
 726             child._impl_meta = weakref.ref(self)
 727
 728         super(MetaConfig, self).__init__(children, session_id, persistent, descr)
 729
 730
 731 def mandatory_warnings(config):
 732     """convenience function to trace Options that are mandatory and
 733     where no value has been set
 734
 735     :returns: generator of mandatory Option's path
 736
 737     """
 738     #if value in cache, properties are not calculated
 739     config.cfgimpl_reset_cache(only=('values',))
 740     for path in config.cfgimpl_get_description().impl_getpaths(
 741             include_groups=True):
 742         try:
 743             config._getattr(path, force_properties=frozenset(('mandatory',)))
 744         except PropertiesOptionError as err:
 745             if err.proptype == ['mandatory']:
 746                 yield path
 747         except ConfigError:
 748             pass
 749     config.cfgimpl_reset_cache(only=('values',))