1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
|
# EFILTER Forensic Query Language
#
# Copyright 2015 Google Inc. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""
EFILTER query type inference.
"""
__author__ = "Adam Sindelar <adamsh@google.com>"
from efilter import dispatch
from efilter import errors
from efilter import ast
from efilter import protocol
from efilter import query as q
from efilter.protocols import boolean
from efilter.transforms import infer_type
@dispatch.multimethod
def validate(expr, scope=None):
"""Use infer_type to get actual types for 'expr' and validate sanity."""
_ = expr, scope
raise NotImplementedError()
@validate.implementation(for_type=q.Query)
def validate(query, scope=None):
try:
return validate(query.root, scope)
except errors.EfilterError as error:
error.query = query.source
raise
@validate.implementation(for_type=ast.ValueExpression)
def validate(expr, scope):
_ = expr, scope
return True
@validate.implementation(for_type=ast.IfElse)
def validate(expr, scope):
# Make sure there's an ELSE block.
if expr.default() is None:
raise errors.EfilterLogicError(
root=expr,
message="Else blocks are required in EFILTER.")
# Make sure conditions evaluate to IBoolean.
for condition, _ in expr.conditions():
t = infer_type.infer_type(condition, scope)
if not protocol.isa(t, boolean.IBoolean):
raise errors.EfilterTypeError(root=expr, actual=t,
expected=boolean.IBoolean)
@validate.implementation(for_type=ast.Complement)
def validate(expr, scope):
t = infer_type.infer_type(expr.value, scope)
if not protocol.isa(t, boolean.IBoolean):
raise errors.EfilterTypeError(root=expr,
actual=t,
expected=boolean.IBoolean)
return True
@validate.implementation(for_type=ast.BinaryExpression)
def validate(expr, scope):
lhs_type = infer_type.infer_type(expr.lhs, scope)
if not (lhs_type is protocol.AnyType
or protocol.isa(lhs_type, expr.type_signature[0])):
raise errors.EfilterTypeError(root=expr.lhs,
expected=expr.type_signature[0],
actual=lhs_type)
rhs_type = infer_type.infer_type(expr.rhs, scope)
if not (lhs_type is protocol.AnyType
or protocol.isa(rhs_type, expr.type_signature[1])):
raise errors.EfilterTypeError(root=expr.rhs,
expected=expr.type_signature[1],
actual=rhs_type)
return True
@validate.implementation(for_type=ast.VariadicExpression)
def validate(expr, scope):
for subexpr in expr.children:
validate(subexpr, scope)
t = infer_type.infer_type(subexpr, scope)
if not (t is protocol.AnyType
or protocol.isa(t, expr.type_signature)):
raise errors.EfilterTypeError(root=subexpr,
expected=expr.type_signature,
actual=t)
return True
|
