def __compile_function(self, function):
parameters = []
for param in function.function_parameters:
cparam = CompiledExpression(param, user_functions=self.user_functions,
known_variables=self.__all_known_variables)
parameters.append(cparam)
self.__collect_attributes( cparam.getDependencies() )
function.function_parameters = tuple(parameters)
def __init__(self, name, attribute_value_select,
user_functions={}, known_variables={}):
self.name = name
self.attributes = attributes = {}
self.reverse_deps = reverse_deps = {}
for (attr, value) in attribute_value_select.iteritems():
if value:
expr = CompiledExpression(value, user_functions=user_functions,
known_variables=known_variables)
dependencies = expr.getDependencies()
else:
expr = None
dependencies = (attr,)
attributes[attr] = expr
for attribute in dependencies:
deps = reverse_deps.get(attribute)
if deps is None:
deps = set()
reverse_deps[attribute] = deps
deps.add(attr)
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) )
class ViewSpecification(object):
"""This is the compiled representation of a view specification.
View specifications are guaranteed not to interfere with each other,
i.e. variables and options are cloned.
"""
_view_functions = ViewFunctions
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) )
def _multi_loop_iterator(self, loops, value_dict):
if not loops:
yield ()
else:
variable, values = loops[0]
variable_name = variable.name
for loop_values in self._multi_loop_iterator(loops[1:], value_dict):
for value in values:
if hasattr(value, 'evaluate'):
value = value.evaluate(value_dict)
variable.value = value
value_dict[variable_name] = value
yield loop_values + (value,)
def iter_loop_variables(self, value_dict=None):
"""Builds an iterator that returns one tuple for each combination of
values of the loop variables. It returns () if there are no loops.
The optional dictionary argument is filled with variable-value pairs.
Note that these must not be changed outside the iterator."""
if value_dict is None:
value_dict = {}
return self._multi_loop_iterator(self.loops, value_dict)
def __compile_rank_function(self, function, object_name, distinct):
if function is None:
return
view_function_class = self._view_functions
if function.name not in view_function_class.VALID_FUNCTIONS:
raise UnknownReferenceError(function.name, view_function_class.VALID_FUNCTIONS)
self.__compile_function(function)
view_functions = view_function_class(object_name)
build_function = getattr(view_functions, function.name)
function.setFunction( build_function(distinct=distinct, *function.function_parameters) )
def __compile_function(self, function):
parameters = []
for param in function.function_parameters:
cparam = CompiledExpression(param, user_functions=self.user_functions,
known_variables=self.__all_known_variables)
parameters.append(cparam)
self.__collect_attributes( cparam.getDependencies() )
function.function_parameters = tuple(parameters)
def __collect_attributes(self, attributes):
"Verify that object refences have been declared."
for attribute in attributes:
object_name = attribute.object_name
if object_name in self.__all_known_variables:
continue
object_attributes = self.__all_attributes.get(object_name, None)
if object_attributes is None:
raise UnknownReferenceError(object_name, self.__all_attributes.keys())
else:
object_attributes.add(attribute)
def getDependencies(self):
return self.__dependencies
def getObjectDependencies(self):
objects = self.__all_attributes.keys()
objects.sort()
return objects
def getQoSParameters(self):
return self.__qos_functions
def __hash__(self):
return self.__hash
