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
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
|
/*
* Copyright (c) 2021, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <LibJS/Runtime/ArgumentsObject.h>
#include <LibJS/Runtime/Completion.h>
#include <LibJS/Runtime/GlobalObject.h>
namespace JS {
ArgumentsObject::ArgumentsObject(Realm& realm, Environment& environment)
: Object(ConstructWithPrototypeTag::Tag, realm.intrinsics().object_prototype())
, m_environment(environment)
{
}
ThrowCompletionOr<void> ArgumentsObject::initialize(Realm& realm)
{
MUST_OR_THROW_OOM(Base::initialize(realm));
set_has_parameter_map();
m_parameter_map = Object::create(realm, nullptr);
return {};
}
void ArgumentsObject::visit_edges(Cell::Visitor& visitor)
{
Base::visit_edges(visitor);
visitor.visit(m_environment);
visitor.visit(m_parameter_map);
}
// 10.4.4.3 [[Get]] ( P, Receiver ), https://tc39.es/ecma262/#sec-arguments-exotic-objects-get-p-receiver
ThrowCompletionOr<Value> ArgumentsObject::internal_get(PropertyKey const& property_key, Value receiver) const
{
// 1. Let map be args.[[ParameterMap]].
auto& map = *m_parameter_map;
// 2. Let isMapped be ! HasOwnProperty(map, P).
bool is_mapped = MUST(m_parameter_map->has_own_property(property_key));
// 3. If isMapped is false, then
if (!is_mapped) {
// a. Return ? OrdinaryGet(args, P, Receiver).
return Object::internal_get(property_key, receiver);
}
// FIXME: a. Assert: map contains a formal parameter mapping for P.
// b. Return ! Get(map, P).
return MUST(map.get(property_key));
}
// 10.4.4.4 [[Set]] ( P, V, Receiver ), https://tc39.es/ecma262/#sec-arguments-exotic-objects-set-p-v-receiver
ThrowCompletionOr<bool> ArgumentsObject::internal_set(PropertyKey const& property_key, Value value, Value receiver)
{
bool is_mapped = false;
// 1. If SameValue(args, Receiver) is false, then
if (!same_value(this, receiver)) {
// a. Let isMapped be false.
is_mapped = false;
} else {
// a. Let map be args.[[ParameterMap]].
// b. Let isMapped be ! HasOwnProperty(map, P).
is_mapped = MUST(parameter_map().has_own_property(property_key));
}
// 3. If isMapped is true, then
if (is_mapped) {
// a. Assert: The following Set will succeed, since formal parameters mapped by arguments objects are always writable.
// b. Perform ! Set(map, P, V, false).
MUST(m_parameter_map->set(property_key, value, Object::ShouldThrowExceptions::No));
}
// 4. Return ? OrdinarySet(args, P, V, Receiver).
return Object::internal_set(property_key, value, receiver);
}
// 10.4.4.5 [[Delete]] ( P ), https://tc39.es/ecma262/#sec-arguments-exotic-objects-delete-p
ThrowCompletionOr<bool> ArgumentsObject::internal_delete(PropertyKey const& property_key)
{
// 1. Let map be args.[[ParameterMap]].
auto& map = parameter_map();
// 2. Let isMapped be ! HasOwnProperty(map, P).
bool is_mapped = MUST(map.has_own_property(property_key));
// 3. Let result be ? OrdinaryDelete(args, P).
bool result = TRY(Object::internal_delete(property_key));
// 4. If result is true and isMapped is true, then
if (result && is_mapped) {
// a. Perform ! map.[[Delete]](P).
MUST(map.internal_delete(property_key));
}
// 5. Return result.
return result;
}
// 10.4.4.1 [[GetOwnProperty]] ( P ), https://tc39.es/ecma262/#sec-arguments-exotic-objects-getownproperty-p
ThrowCompletionOr<Optional<PropertyDescriptor>> ArgumentsObject::internal_get_own_property(PropertyKey const& property_key) const
{
// 1. Let desc be OrdinaryGetOwnProperty(args, P).
auto desc = MUST(Object::internal_get_own_property(property_key));
// 2. If desc is undefined, return desc.
if (!desc.has_value())
return desc;
// 3. Let map be args.[[ParameterMap]].
// 4. Let isMapped be ! HasOwnProperty(map, P).
bool is_mapped = MUST(m_parameter_map->has_own_property(property_key));
// 5. If isMapped is true, then
if (is_mapped) {
// a. Set desc.[[Value]] to ! Get(map, P).
desc->value = MUST(m_parameter_map->get(property_key));
}
// 6. Return desc.
return desc;
}
// 10.4.4.2 [[DefineOwnProperty]] ( P, Desc ), https://tc39.es/ecma262/#sec-arguments-exotic-objects-defineownproperty-p-desc
ThrowCompletionOr<bool> ArgumentsObject::internal_define_own_property(PropertyKey const& property_key, PropertyDescriptor const& descriptor)
{
// 1. Let map be args.[[ParameterMap]].
auto& map = parameter_map();
// 2. Let isMapped be ! HasOwnProperty(map, P).
bool is_mapped = MUST(map.has_own_property(property_key));
// 3. Let newArgDesc be Desc.
auto new_arg_desc = descriptor;
// 4. If isMapped is true and IsDataDescriptor(Desc) is true, then
if (is_mapped && descriptor.is_data_descriptor()) {
// a. If Desc does not have a [[Value]] field and Desc has a [[Writable]] field, and Desc.[[Writable]] is false, then
if (!descriptor.value.has_value() && descriptor.writable.has_value() && descriptor.writable == false) {
// i. Set newArgDesc to a copy of Desc.
new_arg_desc = descriptor;
// ii. Set newArgDesc.[[Value]] to ! Get(map, P).
new_arg_desc.value = MUST(map.get(property_key));
}
}
// 5. Let allowed be ! OrdinaryDefineOwnProperty(args, P, newArgDesc).
bool allowed = MUST(Object::internal_define_own_property(property_key, new_arg_desc));
// 6. If allowed is false, return false.
if (!allowed)
return false;
// 7. If isMapped is true, then
if (is_mapped) {
// a. If IsAccessorDescriptor(Desc) is true, then
if (descriptor.is_accessor_descriptor()) {
// i. Perform ! map.[[Delete]](P).
MUST(map.internal_delete(property_key));
} else {
// i. If Desc has a [[Value]] field, then
if (descriptor.value.has_value()) {
// 1. Assert: The following Set will succeed, since formal parameters mapped by arguments objects are always writable.
// 2. Perform ! Set(map, P, Desc.[[Value]], false).
MUST(map.set(property_key, descriptor.value.value(), Object::ShouldThrowExceptions::No));
}
// ii. If Desc has a [[Writable]] field and Desc.[[Writable]] is false, then
if (descriptor.writable == false) {
// 1. Perform ! map.[[Delete]](P).
MUST(map.internal_delete(property_key));
}
}
}
// 8. Return true.
return true;
}
}
|
