mirror of
https://github.com/SickGear/SickGear.git
synced 2024-12-01 08:53:37 +00:00
282 lines
12 KiB
Python
282 lines
12 KiB
Python
# sql/default_comparator.py
|
|
# Copyright (C) 2005-2014 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
|
|
|
|
"""Default implementation of SQL comparison operations.
|
|
"""
|
|
|
|
from .. import exc, util
|
|
from . import operators
|
|
from . import type_api
|
|
from .elements import BindParameter, True_, False_, BinaryExpression, \
|
|
Null, _const_expr, _clause_element_as_expr, \
|
|
ClauseList, ColumnElement, TextClause, UnaryExpression, \
|
|
collate, _is_literal, _literal_as_text, ClauseElement
|
|
from .selectable import SelectBase, Alias, Selectable, ScalarSelect
|
|
|
|
class _DefaultColumnComparator(operators.ColumnOperators):
|
|
"""Defines comparison and math operations.
|
|
|
|
See :class:`.ColumnOperators` and :class:`.Operators` for descriptions
|
|
of all operations.
|
|
|
|
"""
|
|
|
|
@util.memoized_property
|
|
def type(self):
|
|
return self.expr.type
|
|
|
|
def operate(self, op, *other, **kwargs):
|
|
o = self.operators[op.__name__]
|
|
return o[0](self, self.expr, op, *(other + o[1:]), **kwargs)
|
|
|
|
def reverse_operate(self, op, other, **kwargs):
|
|
o = self.operators[op.__name__]
|
|
return o[0](self, self.expr, op, other, reverse=True, *o[1:], **kwargs)
|
|
|
|
def _adapt_expression(self, op, other_comparator):
|
|
"""evaluate the return type of <self> <op> <othertype>,
|
|
and apply any adaptations to the given operator.
|
|
|
|
This method determines the type of a resulting binary expression
|
|
given two source types and an operator. For example, two
|
|
:class:`.Column` objects, both of the type :class:`.Integer`, will
|
|
produce a :class:`.BinaryExpression` that also has the type
|
|
:class:`.Integer` when compared via the addition (``+``) operator.
|
|
However, using the addition operator with an :class:`.Integer`
|
|
and a :class:`.Date` object will produce a :class:`.Date`, assuming
|
|
"days delta" behavior by the database (in reality, most databases
|
|
other than Postgresql don't accept this particular operation).
|
|
|
|
The method returns a tuple of the form <operator>, <type>.
|
|
The resulting operator and type will be those applied to the
|
|
resulting :class:`.BinaryExpression` as the final operator and the
|
|
right-hand side of the expression.
|
|
|
|
Note that only a subset of operators make usage of
|
|
:meth:`._adapt_expression`,
|
|
including math operators and user-defined operators, but not
|
|
boolean comparison or special SQL keywords like MATCH or BETWEEN.
|
|
|
|
"""
|
|
return op, other_comparator.type
|
|
|
|
def _boolean_compare(self, expr, op, obj, negate=None, reverse=False,
|
|
_python_is_types=(util.NoneType, bool),
|
|
**kwargs):
|
|
|
|
if isinstance(obj, _python_is_types + (Null, True_, False_)):
|
|
|
|
# allow x ==/!= True/False to be treated as a literal.
|
|
# this comes out to "== / != true/false" or "1/0" if those
|
|
# constants aren't supported and works on all platforms
|
|
if op in (operators.eq, operators.ne) and \
|
|
isinstance(obj, (bool, True_, False_)):
|
|
return BinaryExpression(expr,
|
|
_literal_as_text(obj),
|
|
op,
|
|
type_=type_api.BOOLEANTYPE,
|
|
negate=negate, modifiers=kwargs)
|
|
else:
|
|
# all other None/True/False uses IS, IS NOT
|
|
if op in (operators.eq, operators.is_):
|
|
return BinaryExpression(expr, _const_expr(obj),
|
|
operators.is_,
|
|
negate=operators.isnot)
|
|
elif op in (operators.ne, operators.isnot):
|
|
return BinaryExpression(expr, _const_expr(obj),
|
|
operators.isnot,
|
|
negate=operators.is_)
|
|
else:
|
|
raise exc.ArgumentError(
|
|
"Only '=', '!=', 'is_()', 'isnot()' operators can "
|
|
"be used with None/True/False")
|
|
else:
|
|
obj = self._check_literal(expr, op, obj)
|
|
|
|
if reverse:
|
|
return BinaryExpression(obj,
|
|
expr,
|
|
op,
|
|
type_=type_api.BOOLEANTYPE,
|
|
negate=negate, modifiers=kwargs)
|
|
else:
|
|
return BinaryExpression(expr,
|
|
obj,
|
|
op,
|
|
type_=type_api.BOOLEANTYPE,
|
|
negate=negate, modifiers=kwargs)
|
|
|
|
def _binary_operate(self, expr, op, obj, reverse=False, result_type=None,
|
|
**kw):
|
|
obj = self._check_literal(expr, op, obj)
|
|
|
|
if reverse:
|
|
left, right = obj, expr
|
|
else:
|
|
left, right = expr, obj
|
|
|
|
if result_type is None:
|
|
op, result_type = left.comparator._adapt_expression(
|
|
op, right.comparator)
|
|
|
|
return BinaryExpression(left, right, op, type_=result_type)
|
|
|
|
def _scalar(self, expr, op, fn, **kw):
|
|
return fn(expr)
|
|
|
|
def _in_impl(self, expr, op, seq_or_selectable, negate_op, **kw):
|
|
seq_or_selectable = _clause_element_as_expr(seq_or_selectable)
|
|
|
|
if isinstance(seq_or_selectable, ScalarSelect):
|
|
return self._boolean_compare(expr, op, seq_or_selectable,
|
|
negate=negate_op)
|
|
elif isinstance(seq_or_selectable, SelectBase):
|
|
|
|
# TODO: if we ever want to support (x, y, z) IN (select x,
|
|
# y, z from table), we would need a multi-column version of
|
|
# as_scalar() to produce a multi- column selectable that
|
|
# does not export itself as a FROM clause
|
|
|
|
return self._boolean_compare(
|
|
expr, op, seq_or_selectable.as_scalar(),
|
|
negate=negate_op, **kw)
|
|
elif isinstance(seq_or_selectable, (Selectable, TextClause)):
|
|
return self._boolean_compare(expr, op, seq_or_selectable,
|
|
negate=negate_op, **kw)
|
|
elif isinstance(seq_or_selectable, ClauseElement):
|
|
raise exc.InvalidRequestError('in_() accepts'
|
|
' either a list of expressions '
|
|
'or a selectable: %r' % seq_or_selectable)
|
|
|
|
# Handle non selectable arguments as sequences
|
|
args = []
|
|
for o in seq_or_selectable:
|
|
if not _is_literal(o):
|
|
if not isinstance(o, operators.ColumnOperators):
|
|
raise exc.InvalidRequestError('in_() accepts'
|
|
' either a list of expressions '
|
|
'or a selectable: %r' % o)
|
|
elif o is None:
|
|
o = Null()
|
|
else:
|
|
o = expr._bind_param(op, o)
|
|
args.append(o)
|
|
if len(args) == 0:
|
|
|
|
# Special case handling for empty IN's, behave like
|
|
# comparison against zero row selectable. We use != to
|
|
# build the contradiction as it handles NULL values
|
|
# appropriately, i.e. "not (x IN ())" should not return NULL
|
|
# values for x.
|
|
|
|
util.warn('The IN-predicate on "%s" was invoked with an '
|
|
'empty sequence. This results in a '
|
|
'contradiction, which nonetheless can be '
|
|
'expensive to evaluate. Consider alternative '
|
|
'strategies for improved performance.' % expr)
|
|
if op is operators.in_op:
|
|
return expr != expr
|
|
else:
|
|
return expr == expr
|
|
|
|
return self._boolean_compare(expr, op,
|
|
ClauseList(*args).self_group(against=op),
|
|
negate=negate_op)
|
|
|
|
def _unsupported_impl(self, expr, op, *arg, **kw):
|
|
raise NotImplementedError("Operator '%s' is not supported on "
|
|
"this expression" % op.__name__)
|
|
|
|
def _neg_impl(self, expr, op, **kw):
|
|
"""See :meth:`.ColumnOperators.__neg__`."""
|
|
return UnaryExpression(expr, operator=operators.neg)
|
|
|
|
def _match_impl(self, expr, op, other, **kw):
|
|
"""See :meth:`.ColumnOperators.match`."""
|
|
return self._boolean_compare(expr, operators.match_op,
|
|
self._check_literal(expr, operators.match_op,
|
|
other))
|
|
|
|
def _distinct_impl(self, expr, op, **kw):
|
|
"""See :meth:`.ColumnOperators.distinct`."""
|
|
return UnaryExpression(expr, operator=operators.distinct_op,
|
|
type_=expr.type)
|
|
|
|
def _between_impl(self, expr, op, cleft, cright, **kw):
|
|
"""See :meth:`.ColumnOperators.between`."""
|
|
return BinaryExpression(
|
|
expr,
|
|
ClauseList(
|
|
self._check_literal(expr, operators.and_, cleft),
|
|
self._check_literal(expr, operators.and_, cright),
|
|
operator=operators.and_,
|
|
group=False, group_contents=False),
|
|
operators.between_op)
|
|
|
|
def _collate_impl(self, expr, op, other, **kw):
|
|
return collate(expr, other)
|
|
|
|
# a mapping of operators with the method they use, along with
|
|
# their negated operator for comparison operators
|
|
operators = {
|
|
"add": (_binary_operate,),
|
|
"mul": (_binary_operate,),
|
|
"sub": (_binary_operate,),
|
|
"div": (_binary_operate,),
|
|
"mod": (_binary_operate,),
|
|
"truediv": (_binary_operate,),
|
|
"custom_op": (_binary_operate,),
|
|
"concat_op": (_binary_operate,),
|
|
"lt": (_boolean_compare, operators.ge),
|
|
"le": (_boolean_compare, operators.gt),
|
|
"ne": (_boolean_compare, operators.eq),
|
|
"gt": (_boolean_compare, operators.le),
|
|
"ge": (_boolean_compare, operators.lt),
|
|
"eq": (_boolean_compare, operators.ne),
|
|
"like_op": (_boolean_compare, operators.notlike_op),
|
|
"ilike_op": (_boolean_compare, operators.notilike_op),
|
|
"notlike_op": (_boolean_compare, operators.like_op),
|
|
"notilike_op": (_boolean_compare, operators.ilike_op),
|
|
"contains_op": (_boolean_compare, operators.notcontains_op),
|
|
"startswith_op": (_boolean_compare, operators.notstartswith_op),
|
|
"endswith_op": (_boolean_compare, operators.notendswith_op),
|
|
"desc_op": (_scalar, UnaryExpression._create_desc),
|
|
"asc_op": (_scalar, UnaryExpression._create_asc),
|
|
"nullsfirst_op": (_scalar, UnaryExpression._create_nullsfirst),
|
|
"nullslast_op": (_scalar, UnaryExpression._create_nullslast),
|
|
"in_op": (_in_impl, operators.notin_op),
|
|
"notin_op": (_in_impl, operators.in_op),
|
|
"is_": (_boolean_compare, operators.is_),
|
|
"isnot": (_boolean_compare, operators.isnot),
|
|
"collate": (_collate_impl,),
|
|
"match_op": (_match_impl,),
|
|
"distinct_op": (_distinct_impl,),
|
|
"between_op": (_between_impl, ),
|
|
"neg": (_neg_impl,),
|
|
"getitem": (_unsupported_impl,),
|
|
"lshift": (_unsupported_impl,),
|
|
"rshift": (_unsupported_impl,),
|
|
}
|
|
|
|
def _check_literal(self, expr, operator, other):
|
|
if isinstance(other, (ColumnElement, TextClause)):
|
|
if isinstance(other, BindParameter) and \
|
|
other.type._isnull:
|
|
other = other._clone()
|
|
other.type = expr.type
|
|
return other
|
|
elif hasattr(other, '__clause_element__'):
|
|
other = other.__clause_element__()
|
|
elif isinstance(other, type_api.TypeEngine.Comparator):
|
|
other = other.expr
|
|
|
|
if isinstance(other, (SelectBase, Alias)):
|
|
return other.as_scalar()
|
|
elif not isinstance(other, (ColumnElement, TextClause)):
|
|
return expr._bind_param(operator, other)
|
|
else:
|
|
return other
|
|
|