def __init__(self, parsed_viewdef, user_functions={}, new_name=None,
new_parents=None, **variable_defaults):
"Semantically check the view spec, compile it, store it."
self.user_functions = user_functions
self.view_name = new_name or parsed_viewdef.view_name
self.view_parents = new_parents or parsed_viewdef.view_parents
self.select_distinct = distinct = parsed_viewdef.select_distinct
self.select_buckets = parsed_viewdef.select_buckets
# we create new variables here to make different specs independent
self.loops = [ (Variable(str(var.name)), values)
for (var,values) in parsed_viewdef.loops ]
self.loop_variables = [ loop[0] for loop in self.loops ]
self.__all_known_variables = dict( (var,var) for var in self.loop_variables )
# compile and evaluate default values of view variables
self.variable_options = {}
for variable in parsed_viewdef.variable_options:
if variable in self.__all_known_variables:
raise AmbiguousNameError, variable
if variable.name in variable_defaults:
value = variable_defaults[variable.name]
elif variable.default_value:
val_exp = CompiledExpression(variable.default_value,
user_functions=user_functions,
known_variables=self.__all_known_variables)
value = val_exp.evaluate()
else:
value = None
variable = Variable(variable.name, value)
self.variable_options[variable] = variable
self.__all_known_variables[variable] = variable
# build view interface
self.view_object = ViewObjectSpec(
self.view_name, parsed_viewdef.view_attributes,
user_functions=user_functions,
known_variables=self.__all_known_variables )
self.object_select = parsed_viewdef.object_select
self.qos_statements = parsed_viewdef.qos_statements
# prepare __all_attributes to collect all attribute dependencies
self.__all_attributes = {}
for obj in self.object_select.keys():
if obj in self.__all_known_variables:
# duplicate declaration!
raise AmbiguousNameError, obj
self.__all_attributes[obj] = set()
# compile expression for 'where' and 'having'
self.where_expression = CompiledExpression(
parsed_viewdef.where_expression,
user_functions=user_functions,
known_variables=self.__all_known_variables
)
self.having_expression = CompiledExpression(
parsed_viewdef.having_expression,
user_functions=user_functions,
known_variables=self.__all_known_variables
)
# compile expressions in object selector
for object_name, rank_function in self.object_select.iteritems():
if object_name in self.__all_known_variables:
raise AmbiguousNameError, object_name
self.__compile_rank_function(rank_function, object_name, distinct)
# find and verify attribute names in created view and where expression
self.__collect_attributes( self.view_object.all_dependencies() )
self.__collect_attributes( self.where_expression.getDependencies() )
self.__dependencies = tuple(sorted( chain(*self.__all_attributes.values()) ))
# check dependencies of qos statements
qos_attributes = set(chain(*[ st[1] for st in self.qos_statements ]))
unresolved_dependencies = qos_attributes - frozenset(self.__dependencies)
for unknown_attribute in unresolved_dependencies:
raise UnknownReferenceError, (unknown_attribute, self.__dependencies)
# compile and evaluate qos statements
self.__qos_functions = {}
for qos_function, qos_attributes in self.qos_statements:
self.__compile_function(qos_function)
for target_attribute in qos_attributes:
functions = self.__qos_functions.get(target_attribute)
if not functions:
functions = self.__qos_functions[target_attribute] = []
functions.append(qos_function)
select_string = ','.join(sorted('%s[%s]' % item for item in self.object_select.iteritems()))
self.__hash = hash( (str(self.view_object),
self.select_distinct, self.select_buckets,
select_string, self.view_parents,
self.where_expression) )
