"""
* the vregistry handles various types of objects interacting
together. The vregistry handles registration of dynamically loaded
objects and provides a convenient api to access those objects
according to a context
* to interact with the vregistry, objects should inherit from the
VObject abstract class
* the selection procedure has been generalized by delegating to a
selector, which is responsible to score the vobject according to the
current state (req, rset, row, col). At the end of the selection, if
a vobject class has been found, an instance of this class is
returned. The selector is instantiated at vobject registration
:organization: Logilab
:copyright: 2001-2009 LOGILAB S.A. (Paris, FRANCE), license is LGPL v2.
:contact: http://www.logilab.fr/ -- mailto:contact@logilab.fr
:license: GNU Lesser General Public License, v2.1 - http://www.gnu.org/licenses
"""
__docformat__ = "restructuredtext en"
import sys
from os import listdir, stat
from os.path import dirname, join, realpath, split, isdir, exists
from logging import getLogger
import types
from cubicweb import CW_SOFTWARE_ROOT, set_log_methods
from cubicweb import RegistryNotFound, ObjectNotFound, NoSelectableObject
def _toload_info(path, extrapath, _toload=None):
"""return a dictionary of <modname>: <modpath> and an ordered list of
(file, module name) to load
"""
from logilab.common.modutils import modpath_from_file
if _toload is None:
assert isinstance(path, list)
_toload = {}, []
for fileordir in path:
if isdir(fileordir) and exists(join(fileordir, '__init__.py')):
subfiles = [join(fileordir, fname) for fname in listdir(fileordir)]
_toload_info(subfiles, extrapath, _toload)
elif fileordir[-3:] == '.py':
modname = '.'.join(modpath_from_file(fileordir, extrapath))
_toload[0][modname] = fileordir
_toload[1].append((fileordir, modname))
return _toload
class VObject(object):
"""visual object, use to be handled somehow by the visual components
registry.
The following attributes should be set on concret vobject subclasses:
:__registry__:
name of the registry for this object (string like 'views',
'templates'...)
:id:
object's identifier in the registry (string like 'main',
'primary', 'folder_box')
:__select__:
class'selector
Moreover, the `__abstract__` attribute may be set to True to indicate
that a vobject is abstract and should not be registered
"""
# necessary attributes to interact with the registry
id = None
__registry__ = None
__select__ = None
@classmethod
def registered(cls, registry):
"""called by the registry when the vobject has been registered.
It must return the object that will be actually registered (this
may be the right hook to create an instance for example). By
default the vobject is returned without any transformation.
"""
cls.build___select__()
return cls
@classmethod
def selected(cls, *args, **kwargs):
"""called by the registry when the vobject has been selected.
It must return the object that will be actually returned by the
.select method (this may be the right hook to create an
instance for example). By default the selected object is
returned without any transformation.
"""
return cls
@classmethod
def classid(cls):
"""returns a unique identifier for the vobject"""
return '%s.%s' % (cls.__module__, cls.__name__)
# XXX bw compat code
@classmethod
def build___select__(cls):
for klass in cls.mro():
if klass.__name__ == 'AppRsetObject':
continue # the bw compat __selector__ is there
klassdict = klass.__dict__
if ('__select__' in klassdict and '__selectors__' in klassdict
and '__selgenerated__' not in klassdict):
raise TypeError("__select__ and __selectors__ can't be used together on class %s" % cls)
if '__selectors__' in klassdict and '__selgenerated__' not in klassdict:
cls.__selgenerated__ = True
# case where __selectors__ is defined locally (but __select__
# is in a parent class)
selectors = klassdict['__selectors__']
if len(selectors) == 1:
# micro optimization: don't bother with AndSelector if there's
# only one selector
select = _instantiate_selector(selectors[0])
else:
select = AndSelector(*selectors)
cls.__select__ = select
class VRegistry(object):
"""class responsible to register, propose and select the various
elements used to build the web interface. Currently, we have templates,
views, actions and components.
"""
def __init__(self, config):#, cache_size=1000):
self.config = config
# dictionnary of registry (themself dictionnary) by name
self._registries = {}
self._lastmodifs = {}
def reset(self):
self._registries = {}
self._lastmodifs = {}
def __getitem__(self, key):
return self._registries[key]
def get(self, key, default=None):
return self._registries.get(key, default)
def items(self):
return self._registries.items()
def values(self):
return self._registries.values()
def __contains__(self, key):
return key in self._registries
def registry(self, name):
"""return the registry (dictionary of class objects) associated to
this name
"""
try:
return self._registries[name]
except KeyError:
raise RegistryNotFound(name), None, sys.exc_info()[-1]
def registry_objects(self, name, oid=None):
"""returns objects registered with the given oid in the given registry.
If no oid is given, return all objects in this registry
"""
registry = self.registry(name)
if oid:
try:
return registry[oid]
except KeyError:
raise ObjectNotFound(oid), None, sys.exc_info()[-1]
else:
result = []
for objs in registry.values():
result += objs
return result
def object_by_id(self, registry, cid, *args, **kwargs):
"""return the most specific component according to the resultset"""
objects = self[registry][cid]
assert len(objects) == 1, objects
return objects[0].selected(*args, **kwargs)
# methods for explicit (un)registration ###################################
def register_all(self, objects, modname, butclasses=()):
for obj in objects:
try:
if obj.__module__ != modname or obj in butclasses:
continue
oid = obj.id
except AttributeError:
continue
if oid:
self.register(obj)
def register(self, obj, registryname=None, oid=None, clear=False):
"""base method to add an object in the registry"""
assert not '__abstract__' in obj.__dict__
registryname = registryname or obj.__registry__
oid = oid or obj.id
assert oid
registry = self._registries.setdefault(registryname, {})
if clear:
vobjects = registry[oid] = []
else:
vobjects = registry.setdefault(oid, [])
# registered() is technically a classmethod but is not declared
# as such because we need to compose registered in some cases
vobject = obj.registered.im_func(obj, self)
assert not vobject in vobjects, \
'object %s is already registered' % vobject
assert callable(vobject.__select__), vobject
vobjects.append(vobject)
try:
vname = vobject.__name__
except AttributeError:
vname = vobject.__class__.__name__
self.debug('registered vobject %s in registry %s with id %s',
vname, registryname, oid)
# automatic reloading management
self._loadedmods[obj.__module__]['%s.%s' % (obj.__module__, oid)] = obj
def unregister(self, obj, registryname=None):
registryname = registryname or obj.__registry__
registry = self.registry(registryname)
removed_id = obj.classid()
for registered in registry.get(obj.id, ()):
# use classid() to compare classes because vreg will probably
# have its own version of the class, loaded through execfile
if registered.classid() == removed_id:
# XXX automatic reloading management
registry[obj.id].remove(registered)
break
else:
self.warning('can\'t remove %s, no id %s in the %s registry',
removed_id, obj.id, registryname)
def register_and_replace(self, obj, replaced, registryname=None):
# XXXFIXME this is a duplication of unregister()
# remove register_and_replace in favor of unregister + register
# or simplify by calling unregister then register here
if hasattr(replaced, 'classid'):
replaced = replaced.classid()
registryname = registryname or obj.__registry__
registry = self.registry(registryname)
registered_objs = registry.get(obj.id, ())
for index, registered in enumerate(registered_objs):
if registered.classid() == replaced:
del registry[obj.id][index]
break
else:
self.warning('trying to replace an unregistered view %s by %s',
replaced, obj)
self.register(obj, registryname=registryname)
# dynamic selection methods ###############################################
def select(self, vobjects, *args, **kwargs):
"""return an instance of the most specific object according
to parameters
raise NoSelectableObject if not object apply
"""
score, winners = 0, []
for vobject in vobjects:
vobjectscore = vobject.__select__(vobject, *args, **kwargs)
if vobjectscore > score:
score, winners = vobjectscore, [vobject]
elif vobjectscore > 0 and vobjectscore == score:
winners.append(vobject)
if not winners:
raise NoSelectableObject('args: %s\nkwargs: %s %s'
% (args, kwargs.keys(),
[repr(v) for v in vobjects]))
if len(winners) > 1:
if self.config.mode == 'installed':
self.error('select ambiguity, args: %s\nkwargs: %s %s',
args, kwargs.keys(), [repr(v) for v in winners])
else:
raise Exception('select ambiguity, args: %s\nkwargs: %s %s'
% (args, kwargs.keys(),
[repr(v) for v in winners]))
winner = winners[0]
# return the result of the .selected method of the vobject
return winner.selected(*args, **kwargs)
def possible_objects(self, registry, *args, **kwargs):
"""return an iterator on possible objects in a registry for this result set
actions returned are classes, not instances
"""
for vobjects in self.registry(registry).values():
try:
yield self.select(vobjects, *args, **kwargs)
except NoSelectableObject:
continue
def select_object(self, registry, cid, *args, **kwargs):
"""return the most specific component according to the resultset"""
return self.select(self.registry_objects(registry, cid), *args, **kwargs)
# intialization methods ###################################################
def init_registration(self, path, extrapath=None):
# compute list of all modules that have to be loaded
self._toloadmods, filemods = _toload_info(path, extrapath)
self._loadedmods = {}
return filemods
def register_objects(self, path, force_reload=None, extrapath=None):
if force_reload is None:
force_reload = self.config.mode == 'dev'
elif not force_reload:
# force_reload == False usually mean modules have been reloaded
# by another connection, so we want to update the registry
# content even if there has been no module content modification
self.reset()
# need to clean sys.path this to avoid import confusion pb (i.e.
# having the same module loaded as 'cubicweb.web.views' subpackage and
# as views' or 'web.views' subpackage
# this is mainly for testing purpose, we should'nt need this in
# production environment
for webdir in (join(dirname(realpath(__file__)), 'web'),
join(dirname(__file__), 'web')):
if webdir in sys.path:
sys.path.remove(webdir)
if CW_SOFTWARE_ROOT in sys.path:
sys.path.remove(CW_SOFTWARE_ROOT)
# load views from each directory in the application's path
filemods = self.init_registration(path, extrapath)
change = False
for filepath, modname in filemods:
if self.load_file(filepath, modname, force_reload):
change = True
return change
def load_file(self, filepath, modname, force_reload=False):
"""load visual objects from a python file"""
from logilab.common.modutils import load_module_from_name
if modname in self._loadedmods:
return
self._loadedmods[modname] = {}
try:
modified_on = stat(filepath)[-2]
except OSError:
# this typically happens on emacs backup files (.#foo.py)
self.warning('Unable to load %s. It is likely to be a backup file',
filepath)
return False
if filepath in self._lastmodifs:
# only load file if it was modified
if modified_on <= self._lastmodifs[filepath]:
return
# if it was modified, unregister all exisiting objects
# from this module, and keep track of what was unregistered
unregistered = self.unregister_module_vobjects(modname)
else:
unregistered = None
# load the module
module = load_module_from_name(modname, use_sys=not force_reload)
self.load_module(module)
# if something was unregistered, we need to update places where it was
# referenced
if unregistered:
# oldnew_mapping = {}
registered = self._loadedmods[modname]
oldnew_mapping = dict((unregistered[name], registered[name])
for name in unregistered if name in registered)
self.update_registered_subclasses(oldnew_mapping)
self._lastmodifs[filepath] = modified_on
return True
def load_module(self, module):
self.info('loading %s', module)
if hasattr(module, 'registration_callback'):
module.registration_callback(self)
else:
for objname, obj in vars(module).items():
if objname.startswith('_'):
continue
self._load_ancestors_then_object(module.__name__, obj)
self.debug('loaded %s', module)
def _load_ancestors_then_object(self, modname, obj):
# imported classes
objmodname = getattr(obj, '__module__', None)
if objmodname != modname:
if objmodname in self._toloadmods:
self.load_file(self._toloadmods[objmodname], objmodname)
return
# skip non registerable object
try:
if not issubclass(obj, VObject):
return
except TypeError:
return
objname = '%s.%s' % (modname, obj.__name__)
if objname in self._loadedmods[modname]:
return
self._loadedmods[modname][objname] = obj
for parent in obj.__bases__:
self._load_ancestors_then_object(modname, parent)
self.load_object(obj)
def load_object(self, obj):
try:
self.register_vobject_class(obj)
except Exception, ex:
if self.config.mode in ('test', 'dev'):
raise
self.exception('vobject %s registration failed: %s', obj, ex)
# old automatic registration XXX deprecated ###############################
def register_vobject_class(self, cls):
"""handle vobject class registration
vobject class with __abstract__ == True in their local dictionnary or
with a name starting starting by an underscore are not registered.
Also a vobject class needs to have __registry__ and id attributes set
to a non empty string to be registered.
"""
if (cls.__dict__.get('__abstract__') or cls.__name__[0] == '_'
or not cls.__registry__ or not cls.id):
return
regname = cls.__registry__
if '%s.%s' % (regname, cls.id) in self.config['disable-appobjects']:
return
self.register(cls)
def unregister_module_vobjects(self, modname):
"""removes registered objects coming from a given module
returns a dictionnary classid/class of all classes that will need
to be updated after reload (i.e. vobjects referencing classes defined
in the <modname> module)
"""
unregistered = {}
# browse each registered object
for registry, objdict in self.items():
for oid, objects in objdict.items():
for obj in objects[:]:
objname = obj.classid()
# if the vobject is defined in this module, remove it
if objname.startswith(modname):
unregistered[objname] = obj
objects.remove(obj)
self.debug('unregistering %s in %s registry',
objname, registry)
# if not, check if the vobject can be found in baseclasses
# (because we also want subclasses to be updated)
else:
if not isinstance(obj, type):
obj = obj.__class__
for baseclass in obj.__bases__:
if hasattr(baseclass, 'classid'):
baseclassid = baseclass.classid()
if baseclassid.startswith(modname):
unregistered[baseclassid] = baseclass
# update oid entry
if objects:
objdict[oid] = objects
else:
del objdict[oid]
return unregistered
def update_registered_subclasses(self, oldnew_mapping):
"""updates subclasses of re-registered vobjects
if baseviews.PrimaryView is changed, baseviews.py will be reloaded
automatically and the new version of PrimaryView will be registered.
But all existing subclasses must also be notified of this change, and
that's what this method does
:param oldnew_mapping: a dict mapping old version of a class to
the new version
"""
# browse each registered object
for objdict in self.values():
for objects in objdict.values():
for obj in objects:
if not isinstance(obj, type):
obj = obj.__class__
# build new baseclasses tuple
newbases = tuple(oldnew_mapping.get(baseclass, baseclass)
for baseclass in obj.__bases__)
# update obj's baseclasses tuple (__bases__) if needed
if newbases != obj.__bases__:
self.debug('updating %s.%s base classes',
obj.__module__, obj.__name__)
obj.__bases__ = newbases
# init logging
set_log_methods(VObject, getLogger('cubicweb'))
set_log_methods(VRegistry, getLogger('cubicweb.registry'))
# selector base classes and operations ########################################
class Selector(object):
"""base class for selector classes providing implementation
for operators ``&`` and ``|``
This class is only here to give access to binary operators, the
selector logic itself should be implemented in the __call__ method
a selector is called to help choosing the correct object for a
particular context by returning a score (`int`) telling how well
the class given as first argument apply to the given context.
0 score means that the class doesn't apply.
"""
@property
def func_name(self):
# backward compatibility
return self.__class__.__name__
def search_selector(self, selector):
"""search for the given selector or selector instance in the selectors
tree. Return it of None if not found
"""
if self is selector:
return self
if isinstance(selector, type) and isinstance(self, selector):
return self
return None
def __str__(self):
return self.__class__.__name__
def __and__(self, other):
return AndSelector(self, other)
def __rand__(self, other):
return AndSelector(other, self)
def __or__(self, other):
return OrSelector(self, other)
def __ror__(self, other):
return OrSelector(other, self)
def __invert__(self):
return NotSelector(self)
# XXX (function | function) or (function & function) not managed yet
def __call__(self, cls, *args, **kwargs):
return NotImplementedError("selector %s must implement its logic "
"in its __call__ method" % self.__class__)
class MultiSelector(Selector):
"""base class for compound selector classes"""
def __init__(self, *selectors):
self.selectors = self.merge_selectors(selectors)
def __str__(self):
return '%s(%s)' % (self.__class__.__name__,
','.join(str(s) for s in self.selectors))
@classmethod
def merge_selectors(cls, selectors):
"""deal with selector instanciation when necessary and merge
multi-selectors if possible:
AndSelector(AndSelector(sel1, sel2), AndSelector(sel3, sel4))
==> AndSelector(sel1, sel2, sel3, sel4)
"""
merged_selectors = []
for selector in selectors:
try:
selector = _instantiate_selector(selector)
except:
pass
#assert isinstance(selector, Selector), selector
if isinstance(selector, cls):
merged_selectors += selector.selectors
else:
merged_selectors.append(selector)
return merged_selectors
def search_selector(self, selector):
"""search for the given selector or selector instance in the selectors
tree. Return it of None if not found
"""
for childselector in self.selectors:
if childselector is selector:
return childselector
found = childselector.search_selector(selector)
if found is not None:
return found
return None
def objectify_selector(selector_func):
"""convenience decorator for simple selectors where a class definition
would be overkill::
@objectify_selector
def yes(cls, *args, **kwargs):
return 1
"""
return type(selector_func.__name__, (Selector,),
{'__call__': lambda self, *args, **kwargs: selector_func(*args, **kwargs)})
def _instantiate_selector(selector):
"""ensures `selector` is a `Selector` instance
NOTE: This should only be used locally in build___select__()
XXX: then, why not do it ??
"""
if isinstance(selector, types.FunctionType):
return objectify_selector(selector)()
if isinstance(selector, type) and issubclass(selector, Selector):
return selector()
return selector
class AndSelector(MultiSelector):
"""and-chained selectors (formerly known as chainall)"""
def __call__(self, cls, *args, **kwargs):
score = 0
for selector in self.selectors:
partscore = selector(cls, *args, **kwargs)
if not partscore:
return 0
score += partscore
return score
class OrSelector(MultiSelector):
"""or-chained selectors (formerly known as chainfirst)"""
def __call__(self, cls, *args, **kwargs):
for selector in self.selectors:
partscore = selector(cls, *args, **kwargs)
if partscore:
return partscore
return 0
class NotSelector(Selector):
"""negation selector"""
def __init__(self, selector):
self.selector = selector
def __call__(self, cls, *args, **kwargs):
score = self.selector(cls, *args, **kwargs)
return int(not score)
def __str__(self):
return 'NOT(%s)' % super(NotSelector, self).__str__()
# XXX bw compat functions #####################################################
def chainall(*selectors, **kwargs):
"""return a selector chaining given selectors. If one of
the selectors fail, selection will fail, else the returned score
will be the sum of each selector'score
"""
assert selectors
# XXX do we need to create the AndSelector here, a tuple might be enough
selector = AndSelector(*selectors)
if 'name' in kwargs:
selector.__name__ = kwargs['name']
return selector
def chainfirst(*selectors, **kwargs):
"""return a selector chaining given selectors. If all
the selectors fail, selection will fail, else the returned score
will be the first non-zero selector score
"""
assert selectors
selector = OrSelector(*selectors)
if 'name' in kwargs:
selector.__name__ = kwargs['name']
return selector