--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/cubicweb/hooks/synccomputed.py Sat Jan 16 13:48:51 2016 +0100
@@ -0,0 +1,227 @@
+# copyright 2014 LOGILAB S.A. (Paris, FRANCE), all rights reserved.
+# contact http://www.logilab.fr/ -- mailto:contact@logilab.fr
+#
+# This file is part of CubicWeb.
+#
+# CubicWeb is free software: you can redistribute it and/or modify it under the
+# terms of the GNU Lesser General Public License as published by the Free
+# Software Foundation, either version 2.1 of the License, or (at your option)
+# any later version.
+#
+# CubicWeb 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 Lesser General Public License for more
+# details.
+#
+# You should have received a copy of the GNU Lesser General Public License along
+# with CubicWeb. If not, see <http://www.gnu.org/licenses/>.
+"""Hooks for synchronizing computed attributes"""
+
+__docformat__ = "restructuredtext en"
+from cubicweb import _
+
+from collections import defaultdict
+
+from rql import nodes
+
+from cubicweb.server import hook
+
+
+class RecomputeAttributeOperation(hook.DataOperationMixIn, hook.Operation):
+ """Operation to recompute caches of computed attribute at commit time,
+ depending on what's have been modified in the transaction and avoiding to
+ recompute twice the same attribute
+ """
+ containercls = dict
+ def add_data(self, computed_attribute, eid=None):
+ try:
+ self._container[computed_attribute].add(eid)
+ except KeyError:
+ self._container[computed_attribute] = set((eid,))
+
+ def precommit_event(self):
+ for computed_attribute_rdef, eids in self.get_data().items():
+ attr = computed_attribute_rdef.rtype
+ formula = computed_attribute_rdef.formula
+ select = self.cnx.repo.vreg.rqlhelper.parse(formula).children[0]
+ xvar = select.get_variable('X')
+ select.add_selected(xvar, index=0)
+ select.add_group_var(xvar, index=0)
+ if None in eids:
+ select.add_type_restriction(xvar, computed_attribute_rdef.subject)
+ else:
+ select.add_eid_restriction(xvar, eids)
+ update_rql = 'SET X %s %%(value)s WHERE X eid %%(x)s' % attr
+ for eid, value in self.cnx.execute(select.as_string()):
+ self.cnx.execute(update_rql, {'value': value, 'x': eid})
+
+
+class EntityWithCACreatedHook(hook.Hook):
+ """When creating an entity that has some computed attribute, those
+ attributes have to be computed.
+
+ Concret class of this hook are generated at registration time by
+ introspecting the schema.
+ """
+ __abstract__ = True
+ events = ('after_add_entity',)
+ # list of computed attribute rdefs that have to be recomputed
+ computed_attributes = None
+
+ def __call__(self):
+ for rdef in self.computed_attributes:
+ RecomputeAttributeOperation.get_instance(self._cw).add_data(
+ rdef, self.entity.eid)
+
+
+class RelationInvolvedInCAModifiedHook(hook.Hook):
+ """When some relation used in a computed attribute is updated, those
+ attributes have to be recomputed.
+
+ Concret class of this hook are generated at registration time by
+ introspecting the schema.
+ """
+ __abstract__ = True
+ events = ('after_add_relation', 'before_delete_relation')
+ # list of (computed attribute rdef, optimize_on) that have to be recomputed
+ optimized_computed_attributes = None
+
+ def __call__(self):
+ for rdef, optimize_on in self.optimized_computed_attributes:
+ if optimize_on is None:
+ eid = None
+ else:
+ eid = getattr(self, optimize_on)
+ RecomputeAttributeOperation.get_instance(self._cw).add_data(rdef, eid)
+
+
+class AttributeInvolvedInCAModifiedHook(hook.Hook):
+ """When some attribute used in a computed attribute is updated, those
+ attributes have to be recomputed.
+
+ Concret class of this hook are generated at registration time by
+ introspecting the schema.
+ """
+ __abstract__ = True
+ events = ('after_update_entity',)
+ # list of (computed attribute rdef, attributes of this entity type involved)
+ # that may have to be recomputed
+ attributes_computed_attributes = None
+
+ def __call__(self):
+ edited_attributes = frozenset(self.entity.cw_edited)
+ for rdef, used_attributes in self.attributes_computed_attributes.items():
+ if edited_attributes.intersection(used_attributes):
+ # XXX optimize if the modified attributes belong to the same
+ # entity as the computed attribute
+ RecomputeAttributeOperation.get_instance(self._cw).add_data(rdef)
+
+
+# code generation at registration time #########################################
+
+def _optimize_on(formula_select, rtype):
+ """Given a formula and some rtype, tells whether on update of the given
+ relation, formula may be recomputed only for rhe relation's subject
+ ('eidfrom' returned), object ('eidto' returned) or None.
+
+ Optimizing is only possible when X is used as direct subject/object of this
+ relation, else we may miss some necessary update.
+ """
+ for rel in formula_select.get_nodes(nodes.Relation):
+ if rel.r_type == rtype:
+ sub = rel.get_variable_parts()[0]
+ obj = rel.get_variable_parts()[1]
+ if sub.name == 'X':
+ return 'eidfrom'
+ elif obj.name == 'X':
+ return 'eidto'
+ else:
+ return None
+
+
+class _FormulaDependenciesMatrix(object):
+ """This class computes and represents the dependencies of computed attributes
+ towards relations and attributes
+ """
+
+ def __init__(self, schema):
+ """Analyzes the schema to compute the dependencies"""
+ # entity types holding some computed attribute {etype: [computed rdefs]}
+ self.computed_attribute_by_etype = defaultdict(list)
+ # depending entity types {dep. etype: {computed rdef: dep. etype attributes}}
+ self.computed_attribute_by_etype_attrs = defaultdict(lambda: defaultdict(set))
+ # depending relations def {dep. rdef: [computed rdefs]
+ self.computed_attribute_by_relation = defaultdict(list) # by rdef
+ # Walk through all attributes definitions
+ for rdef in schema.iter_computed_attributes():
+ self.computed_attribute_by_etype[rdef.subject.type].append(rdef)
+ # extract the relations it depends upon - `rdef.formula_select` is
+ # expected to have been set by finalize_computed_attributes
+ select = rdef.formula_select
+ for rel_node in select.get_nodes(nodes.Relation):
+ if rel_node.is_types_restriction():
+ continue
+ rschema = schema.rschema(rel_node.r_type)
+ lhs, rhs = rel_node.get_variable_parts()
+ for sol in select.solutions:
+ subject_etype = sol[lhs.name]
+ if isinstance(rhs, nodes.VariableRef):
+ object_etypes = set(sol[rhs.name] for sol in select.solutions)
+ else:
+ object_etypes = rschema.objects(subject_etype)
+ for object_etype in object_etypes:
+ if rschema.final:
+ attr_for_computations = self.computed_attribute_by_etype_attrs[subject_etype]
+ attr_for_computations[rdef].add(rschema.type)
+ else:
+ depend_on_rdef = rschema.rdefs[subject_etype, object_etype]
+ self.computed_attribute_by_relation[depend_on_rdef].append(rdef)
+
+ def generate_entity_creation_hooks(self):
+ for etype, computed_attributes in self.computed_attribute_by_etype.items():
+ regid = 'computed_attribute.%s_created' % etype
+ selector = hook.is_instance(etype)
+ yield type('%sCreatedHook' % etype,
+ (EntityWithCACreatedHook,),
+ {'__regid__': regid,
+ '__select__': hook.Hook.__select__ & selector,
+ 'computed_attributes': computed_attributes})
+
+ def generate_relation_change_hooks(self):
+ for rdef, computed_attributes in self.computed_attribute_by_relation.items():
+ regid = 'computed_attribute.%s_modified' % rdef.rtype
+ selector = hook.match_rtype(rdef.rtype.type,
+ frometypes=(rdef.subject.type,),
+ toetypes=(rdef.object.type,))
+ optimized_computed_attributes = []
+ for computed_rdef in computed_attributes:
+ optimized_computed_attributes.append(
+ (computed_rdef,
+ _optimize_on(computed_rdef.formula_select, rdef.rtype))
+ )
+ yield type('%sModifiedHook' % rdef.rtype,
+ (RelationInvolvedInCAModifiedHook,),
+ {'__regid__': regid,
+ '__select__': hook.Hook.__select__ & selector,
+ 'optimized_computed_attributes': optimized_computed_attributes})
+
+ def generate_entity_update_hooks(self):
+ for etype, attributes_computed_attributes in self.computed_attribute_by_etype_attrs.items():
+ regid = 'computed_attribute.%s_updated' % etype
+ selector = hook.is_instance(etype)
+ yield type('%sModifiedHook' % etype,
+ (AttributeInvolvedInCAModifiedHook,),
+ {'__regid__': regid,
+ '__select__': hook.Hook.__select__ & selector,
+ 'attributes_computed_attributes': attributes_computed_attributes})
+
+
+def registration_callback(vreg):
+ vreg.register_all(globals().values(), __name__)
+ dependencies = _FormulaDependenciesMatrix(vreg.schema)
+ for hook_class in dependencies.generate_entity_creation_hooks():
+ vreg.register(hook_class)
+ for hook_class in dependencies.generate_relation_change_hooks():
+ vreg.register(hook_class)
+ for hook_class in dependencies.generate_entity_update_hooks():
+ vreg.register(hook_class)