You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
126 lines
4.3 KiB
Python
126 lines
4.3 KiB
Python
# orm/evaluator.py
|
|
# Copyright (C) 2005-2013 the SQLAlchemy authors and contributors <see AUTHORS file>
|
|
#
|
|
# This module is part of SQLAlchemy and is released under
|
|
# the MIT License: http://www.opensource.org/licenses/mit-license.php
|
|
|
|
import operator
|
|
from ..sql import operators
|
|
|
|
|
|
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_false(self, clause):
|
|
return lambda obj: False
|
|
|
|
def visit_true(self, clause):
|
|
return lambda obj: True
|
|
|
|
def visit_column(self, clause):
|
|
if 'parentmapper' in clause._annotations:
|
|
key = clause._annotations['parentmapper'].\
|
|
_columntoproperty[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
|