Line data Source code
1 : // Copyright 2012 the V8 project authors. All rights reserved.
2 : // Use of this source code is governed by a BSD-style license that can be
3 : // found in the LICENSE file.
4 :
5 : #ifndef V8_KEYS_H_
6 : #define V8_KEYS_H_
7 :
8 : #include "src/objects.h"
9 : #include "src/objects/hash-table.h"
10 : #include "src/objects/ordered-hash-table.h"
11 :
12 : namespace v8 {
13 : namespace internal {
14 :
15 : class JSProxy;
16 :
17 : enum AddKeyConversion { DO_NOT_CONVERT, CONVERT_TO_ARRAY_INDEX };
18 :
19 : // This is a helper class for JSReceiver::GetKeys which collects and sorts keys.
20 : // GetKeys needs to sort keys per prototype level, first showing the integer
21 : // indices from elements then the strings from the properties. However, this
22 : // does not apply to proxies which are in full control of how the keys are
23 : // sorted.
24 : //
25 : // For performance reasons the KeyAccumulator internally separates integer keys
26 : // in |elements_| into sorted lists per prototype level. String keys are
27 : // collected in |string_properties_|, a single OrderedHashSet (similar for
28 : // Symbols in |symbol_properties_|. To separate the keys per level later when
29 : // assembling the final list, |levelLengths_| keeps track of the number of
30 : // String and Symbol keys per level.
31 : //
32 : // Only unique keys are kept by the KeyAccumulator, strings are stored in a
33 : // HashSet for inexpensive lookups. Integer keys are kept in sorted lists which
34 : // are more compact and allow for reasonably fast includes check.
35 : class KeyAccumulator final {
36 : public:
37 0 : KeyAccumulator(Isolate* isolate, KeyCollectionMode mode,
38 : PropertyFilter filter)
39 1200618 : : isolate_(isolate), mode_(mode), filter_(filter) {}
40 : ~KeyAccumulator() = default;
41 :
42 : static MaybeHandle<FixedArray> GetKeys(
43 : Handle<JSReceiver> object, KeyCollectionMode mode, PropertyFilter filter,
44 : GetKeysConversion keys_conversion = GetKeysConversion::kKeepNumbers,
45 : bool is_for_in = false, bool skip_indices = false);
46 :
47 : Handle<FixedArray> GetKeys(
48 : GetKeysConversion convert = GetKeysConversion::kKeepNumbers);
49 : Maybe<bool> CollectKeys(Handle<JSReceiver> receiver,
50 : Handle<JSReceiver> object);
51 : Maybe<bool> CollectOwnElementIndices(Handle<JSReceiver> receiver,
52 : Handle<JSObject> object);
53 : Maybe<bool> CollectOwnPropertyNames(Handle<JSReceiver> receiver,
54 : Handle<JSObject> object);
55 : Maybe<bool> CollectAccessCheckInterceptorKeys(
56 : Handle<AccessCheckInfo> access_check_info, Handle<JSReceiver> receiver,
57 : Handle<JSObject> object);
58 :
59 : // Might return directly the object's enum_cache, copy the result before using
60 : // as an elements backing store for a JSObject.
61 : // Does not throw for uninitialized exports in module namespace objects, so
62 : // this has to be checked separately.
63 : static Handle<FixedArray> GetOwnEnumPropertyKeys(Isolate* isolate,
64 : Handle<JSObject> object);
65 :
66 : void AddKey(Object key, AddKeyConversion convert = DO_NOT_CONVERT);
67 : void AddKey(Handle<Object> key, AddKeyConversion convert = DO_NOT_CONVERT);
68 : void AddKeys(Handle<FixedArray> array, AddKeyConversion convert);
69 : void AddKeys(Handle<JSObject> array_like, AddKeyConversion convert);
70 :
71 : // Jump to the next level, pushing the current |levelLength_| to
72 : // |levelLengths_| and adding a new list to |elements_|.
73 : Isolate* isolate() { return isolate_; }
74 : // Filter keys based on their property descriptors.
75 : PropertyFilter filter() { return filter_; }
76 : // The collection mode defines whether we collect the keys from the prototype
77 : // chain or only look at the receiver.
78 : KeyCollectionMode mode() { return mode_; }
79 : // In case of for-in loops we have to treat JSProxy keys differently and
80 : // deduplicate them. Additionally we convert JSProxy keys back to array
81 : // indices.
82 1188671 : void set_is_for_in(bool value) { is_for_in_ = value; }
83 1195368 : void set_skip_indices(bool value) { skip_indices_ = value; }
84 : // The last_non_empty_prototype is used to limit the prototypes for which
85 : // we have to keep track of non-enumerable keys that can shadow keys
86 : // repeated on the prototype chain.
87 : void set_last_non_empty_prototype(Handle<JSReceiver> object) {
88 1188671 : last_non_empty_prototype_ = object;
89 : }
90 : // Shadowing keys are used to filter keys. This happens when non-enumerable
91 : // keys appear again on the prototype chain.
92 : void AddShadowingKey(Object key);
93 : void AddShadowingKey(Handle<Object> key);
94 :
95 : private:
96 : Maybe<bool> CollectOwnKeys(Handle<JSReceiver> receiver,
97 : Handle<JSObject> object);
98 : Maybe<bool> CollectOwnJSProxyKeys(Handle<JSReceiver> receiver,
99 : Handle<JSProxy> proxy);
100 : Maybe<bool> CollectOwnJSProxyTargetKeys(Handle<JSProxy> proxy,
101 : Handle<JSReceiver> target);
102 : Maybe<bool> AddKeysFromJSProxy(Handle<JSProxy> proxy,
103 : Handle<FixedArray> keys);
104 : bool IsShadowed(Handle<Object> key);
105 : bool HasShadowingKeys();
106 : Handle<OrderedHashSet> keys();
107 :
108 : Isolate* isolate_;
109 : // keys_ is either an Handle<OrderedHashSet> or in the case of own JSProxy
110 : // keys a Handle<FixedArray>. The OrderedHashSet is in-place converted to the
111 : // result list, a FixedArray containing all collected keys.
112 : Handle<FixedArray> keys_;
113 : Handle<JSReceiver> last_non_empty_prototype_;
114 : Handle<ObjectHashSet> shadowing_keys_;
115 : KeyCollectionMode mode_;
116 : PropertyFilter filter_;
117 : bool is_for_in_ = false;
118 : bool skip_indices_ = false;
119 : // For all the keys on the first receiver adding a shadowing key we can skip
120 : // the shadow check.
121 : bool skip_shadow_check_ = true;
122 :
123 : DISALLOW_COPY_AND_ASSIGN(KeyAccumulator);
124 : };
125 :
126 : // The FastKeyAccumulator handles the cases where there are no elements on the
127 : // prototype chain and forwords the complex/slow cases to the normal
128 : // KeyAccumulator. This significantly speeds up the cases where the OWN_ONLY
129 : // case where we do not have to walk the prototype chain.
130 : class FastKeyAccumulator {
131 : public:
132 : FastKeyAccumulator(Isolate* isolate, Handle<JSReceiver> receiver,
133 : KeyCollectionMode mode, PropertyFilter filter,
134 : bool is_for_in = false, bool skip_indices = false)
135 : : isolate_(isolate),
136 : receiver_(receiver),
137 : mode_(mode),
138 : filter_(filter),
139 : is_for_in_(is_for_in),
140 2773360 : skip_indices_(skip_indices) {
141 1386680 : Prepare();
142 : }
143 :
144 : bool is_receiver_simple_enum() { return is_receiver_simple_enum_; }
145 : bool has_empty_prototype() { return has_empty_prototype_; }
146 :
147 : MaybeHandle<FixedArray> GetKeys(
148 : GetKeysConversion convert = GetKeysConversion::kKeepNumbers);
149 :
150 : private:
151 : void Prepare();
152 : MaybeHandle<FixedArray> GetKeysFast(GetKeysConversion convert);
153 : MaybeHandle<FixedArray> GetKeysSlow(GetKeysConversion convert);
154 :
155 : MaybeHandle<FixedArray> GetOwnKeysWithUninitializedEnumCache();
156 :
157 : Isolate* isolate_;
158 : Handle<JSReceiver> receiver_;
159 : Handle<JSReceiver> last_non_empty_prototype_;
160 : KeyCollectionMode mode_;
161 : PropertyFilter filter_;
162 : bool is_for_in_ = false;
163 : bool skip_indices_ = false;
164 : bool is_receiver_simple_enum_ = false;
165 : bool has_empty_prototype_ = false;
166 :
167 : DISALLOW_COPY_AND_ASSIGN(FastKeyAccumulator);
168 : };
169 :
170 : } // namespace internal
171 : } // namespace v8
172 :
173 : #endif // V8_KEYS_H_
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