105 lines
3.8 KiB
Python
105 lines
3.8 KiB
Python
|
import operator
|
||
|
|
from sqlalchemy.sql import operators, functions
|
||
|
|
from sqlalchemy.sql import expression as sql
|
||
|
|
|
||
|
|
|
||
|
|
class UnevaluatableError(Exception):
|
||
|
|
pass
|
||
|
|
|
||
|
|
_straight_ops = set(getattr(operators, op)
|
||
|
|
for op in ('add', 'mul', 'sub',
|
||
|
|
# Py2K
|
||
|
|
'div',
|
||
|
|
# end Py2K
|
||
|
|
'mod', 'truediv',
|
||
|
|
'lt', 'le', 'ne', 'gt', 'ge', 'eq'))
|
||
|
|
|
||
|
|
|
||
|
|
_notimplemented_ops = set(getattr(operators, op)
|
||
|
|
for op in ('like_op', 'notlike_op', 'ilike_op',
|
||
|
|
'notilike_op', 'between_op', 'in_op',
|
||
|
|
'notin_op', 'endswith_op', 'concat_op'))
|
||
|
|
|
||
|
|
class EvaluatorCompiler(object):
|
||
|
|
def process(self, clause):
|
||
|
|
meth = getattr(self, "visit_%s" % clause.__visit_name__, None)
|
||
|
|
if not meth:
|
||
|
|
raise UnevaluatableError("Cannot evaluate %s" % type(clause).__name__)
|
||
|
|
return meth(clause)
|
||
|
|
|
||
|
|
def visit_grouping(self, clause):
|
||
|
|
return self.process(clause.element)
|
||
|
|
|
||
|
|
def visit_null(self, clause):
|
||
|
|
return lambda obj: None
|
||
|
|
|
||
|
|
def visit_column(self, clause):
|
||
|
|
if 'parentmapper' in clause._annotations:
|
||
|
|
key = clause._annotations['parentmapper']._get_col_to_prop(clause).key
|
||
|
|
else:
|
||
|
|
key = clause.key
|
||
|
|
get_corresponding_attr = operator.attrgetter(key)
|
||
|
|
return lambda obj: get_corresponding_attr(obj)
|
||
|
|
|
||
|
|
def visit_clauselist(self, clause):
|
||
|
|
evaluators = map(self.process, clause.clauses)
|
||
|
|
if clause.operator is operators.or_:
|
||
|
|
def evaluate(obj):
|
||
|
|
has_null = False
|
||
|
|
for sub_evaluate in evaluators:
|
||
|
|
value = sub_evaluate(obj)
|
||
|
|
if value:
|
||
|
|
return True
|
||
|
|
has_null = has_null or value is None
|
||
|
|
if has_null:
|
||
|
|
return None
|
||
|
|
return False
|
||
|
|
elif clause.operator is operators.and_:
|
||
|
|
def evaluate(obj):
|
||
|
|
for sub_evaluate in evaluators:
|
||
|
|
value = sub_evaluate(obj)
|
||
|
|
if not value:
|
||
|
|
if value is None:
|
||
|
|
return None
|
||
|
|
return False
|
||
|
|
return True
|
||
|
|
else:
|
||
|
|
raise UnevaluatableError("Cannot evaluate clauselist with operator %s" % clause.operator)
|
||
|
|
|
||
|
|
return evaluate
|
||
|
|
|
||
|
|
def visit_binary(self, clause):
|
||
|
|
eval_left,eval_right = map(self.process, [clause.left, clause.right])
|
||
|
|
operator = clause.operator
|
||
|
|
if operator is operators.is_:
|
||
|
|
def evaluate(obj):
|
||
|
|
return eval_left(obj) == eval_right(obj)
|
||
|
|
elif operator is operators.isnot:
|
||
|
|
def evaluate(obj):
|
||
|
|
return eval_left(obj) != eval_right(obj)
|
||
|
|
elif operator in _straight_ops:
|
||
|
|
def evaluate(obj):
|
||
|
|
left_val = eval_left(obj)
|
||
|
|
right_val = eval_right(obj)
|
||
|
|
if left_val is None or right_val is None:
|
||
|
|
return None
|
||
|
|
return operator(eval_left(obj), eval_right(obj))
|
||
|
|
else:
|
||
|
|
raise UnevaluatableError("Cannot evaluate %s with operator %s" % (type(clause).__name__, clause.operator))
|
||
|
|
return evaluate
|
||
|
|
|
||
|
|
def visit_unary(self, clause):
|
||
|
|
eval_inner = self.process(clause.element)
|
||
|
|
if clause.operator is operators.inv:
|
||
|
|
def evaluate(obj):
|
||
|
|
value = eval_inner(obj)
|
||
|
|
if value is None:
|
||
|
|
return None
|
||
|
|
return not value
|
||
|
|
return evaluate
|
||
|
|
raise UnevaluatableError("Cannot evaluate %s with operator %s" % (type(clause).__name__, clause.operator))
|
||
|
|
|
||
|
|
def visit_bindparam(self, clause):
|
||
|
|
val = clause.value
|
||
|
|
return lambda obj: val
|