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_ELEMENTS_H_
6#define V8_ELEMENTS_H_
7
8#include "src/elements-kind.h"
9#include "src/keys.h"
10#include "src/objects.h"
11
12namespace v8 {
13namespace internal {
14
15class JSTypedArray;
16
17// Abstract base class for handles that can operate on objects with differing
18// ElementsKinds.
19class ElementsAccessor {
20 public:
21 explicit ElementsAccessor(const char* name) : name_(name) { }
22 virtual ~ElementsAccessor() = default;
23
24 const char* name() const { return name_; }
25
26 // Returns a shared ElementsAccessor for the specified ElementsKind.
27 static ElementsAccessor* ForKind(ElementsKind elements_kind) {
28 DCHECK_LT(static_cast<int>(elements_kind), kElementsKindCount);
29 return elements_accessors_[elements_kind];
30 }
31
32 // Checks the elements of an object for consistency, asserting when a problem
33 // is found.
34 virtual void Validate(JSObject obj) = 0;
35
36 // Returns true if a holder contains an element with the specified index
37 // without iterating up the prototype chain. The caller can optionally pass
38 // in the backing store to use for the check, which must be compatible with
39 // the ElementsKind of the ElementsAccessor. If backing_store is nullptr, the
40 // holder->elements() is used as the backing store. If a |filter| is
41 // specified the PropertyAttributes of the element at the given index
42 // are compared to the given |filter|. If they match/overlap the given
43 // index is ignored. Note that only Dictionary elements have custom
44 // PropertyAttributes associated, hence the |filter| argument is ignored for
45 // all but DICTIONARY_ELEMENTS and SLOW_SLOPPY_ARGUMENTS_ELEMENTS.
46 virtual bool HasElement(JSObject holder, uint32_t index,
47 FixedArrayBase backing_store,
48 PropertyFilter filter = ALL_PROPERTIES) = 0;
49
50 inline bool HasElement(JSObject holder, uint32_t index,
51 PropertyFilter filter = ALL_PROPERTIES);
52
53 // Note: this is currently not implemented for string wrapper and
54 // typed array elements.
55 virtual bool HasEntry(JSObject holder, uint32_t entry) = 0;
56
57 // TODO(cbruni): HasEntry and Get should not be exposed publicly with the
58 // entry parameter.
59 virtual Handle<Object> Get(Handle<JSObject> holder, uint32_t entry) = 0;
60
61 virtual bool HasAccessors(JSObject holder) = 0;
62 virtual uint32_t NumberOfElements(JSObject holder) = 0;
63
64 // Modifies the length data property as specified for JSArrays and resizes the
65 // underlying backing store accordingly. The method honors the semantics of
66 // changing array sizes as defined in EcmaScript 5.1 15.4.5.2, i.e. array that
67 // have non-deletable elements can only be shrunk to the size of highest
68 // element that is non-deletable.
69 virtual void SetLength(Handle<JSArray> holder, uint32_t new_length) = 0;
70
71
72 // If kCopyToEnd is specified as the copy_size to CopyElements, it copies all
73 // of elements from source after source_start to the destination array.
74 static const int kCopyToEnd = -1;
75 // If kCopyToEndAndInitializeToHole is specified as the copy_size to
76 // CopyElements, it copies all of elements from source after source_start to
77 // destination array, padding any remaining uninitialized elements in the
78 // destination array with the hole.
79 static const int kCopyToEndAndInitializeToHole = -2;
80
81 // Copy all indices that have elements from |object| into the given
82 // KeyAccumulator. For Dictionary-based element-kinds we filter out elements
83 // whose PropertyAttribute match |filter|.
84 virtual void CollectElementIndices(Handle<JSObject> object,
85 Handle<FixedArrayBase> backing_store,
86 KeyAccumulator* keys) = 0;
87
88 inline void CollectElementIndices(Handle<JSObject> object,
89 KeyAccumulator* keys);
90
91 virtual Maybe<bool> CollectValuesOrEntries(
92 Isolate* isolate, Handle<JSObject> object,
93 Handle<FixedArray> values_or_entries, bool get_entries, int* nof_items,
94 PropertyFilter filter = ALL_PROPERTIES) = 0;
95
96 virtual MaybeHandle<FixedArray> PrependElementIndices(
97 Handle<JSObject> object, Handle<FixedArrayBase> backing_store,
98 Handle<FixedArray> keys, GetKeysConversion convert,
99 PropertyFilter filter = ALL_PROPERTIES) = 0;
100
101 inline MaybeHandle<FixedArray> PrependElementIndices(
102 Handle<JSObject> object, Handle<FixedArray> keys,
103 GetKeysConversion convert, PropertyFilter filter = ALL_PROPERTIES);
104
105 virtual void AddElementsToKeyAccumulator(Handle<JSObject> receiver,
106 KeyAccumulator* accumulator,
107 AddKeyConversion convert) = 0;
108
109 virtual void TransitionElementsKind(Handle<JSObject> object,
110 Handle<Map> map) = 0;
111 virtual void GrowCapacityAndConvert(Handle<JSObject> object,
112 uint32_t capacity) = 0;
113 // Unlike GrowCapacityAndConvert do not attempt to convert the backing store
114 // and simply return false in this case.
115 virtual bool GrowCapacity(Handle<JSObject> object, uint32_t index) = 0;
116
117 static void InitializeOncePerProcess();
118 static void TearDown();
119
120 virtual void Set(Handle<JSObject> holder, uint32_t entry, Object value) = 0;
121
122 virtual void Add(Handle<JSObject> object, uint32_t index,
123 Handle<Object> value, PropertyAttributes attributes,
124 uint32_t new_capacity) = 0;
125
126 static Handle<JSArray> Concat(Isolate* isolate, Arguments* args,
127 uint32_t concat_size, uint32_t result_length);
128
129 virtual uint32_t Push(Handle<JSArray> receiver, Arguments* args,
130 uint32_t push_size) = 0;
131
132 virtual uint32_t Unshift(Handle<JSArray> receiver, Arguments* args,
133 uint32_t unshift_size) = 0;
134
135 virtual Handle<JSObject> Slice(Handle<JSObject> receiver, uint32_t start,
136 uint32_t end) = 0;
137
138 virtual Handle<Object> Pop(Handle<JSArray> receiver) = 0;
139
140 virtual Handle<Object> Shift(Handle<JSArray> receiver) = 0;
141
142 virtual Handle<NumberDictionary> Normalize(Handle<JSObject> object) = 0;
143
144 virtual uint32_t GetCapacity(JSObject holder,
145 FixedArrayBase backing_store) = 0;
146
147 virtual Object Fill(Handle<JSObject> receiver, Handle<Object> obj_value,
148 uint32_t start, uint32_t end) = 0;
149
150 // Check an Object's own elements for an element (using SameValueZero
151 // semantics)
152 virtual Maybe<bool> IncludesValue(Isolate* isolate, Handle<JSObject> receiver,
153 Handle<Object> value, uint32_t start,
154 uint32_t length) = 0;
155
156 // Check an Object's own elements for the index of an element (using SameValue
157 // semantics)
158 virtual Maybe<int64_t> IndexOfValue(Isolate* isolate,
159 Handle<JSObject> receiver,
160 Handle<Object> value, uint32_t start,
161 uint32_t length) = 0;
162
163 virtual Maybe<int64_t> LastIndexOfValue(Handle<JSObject> receiver,
164 Handle<Object> value,
165 uint32_t start) = 0;
166
167 virtual void Reverse(JSObject receiver) = 0;
168
169 virtual void CopyElements(Isolate* isolate, Handle<FixedArrayBase> source,
170 ElementsKind source_kind,
171 Handle<FixedArrayBase> destination, int size) = 0;
172
173 virtual Object CopyElements(Handle<Object> source,
174 Handle<JSObject> destination, size_t length,
175 uint32_t offset = 0) = 0;
176
177 virtual Handle<FixedArray> CreateListFromArrayLike(Isolate* isolate,
178 Handle<JSObject> object,
179 uint32_t length) = 0;
180
181 virtual void CopyTypedArrayElementsSlice(JSTypedArray source,
182 JSTypedArray destination,
183 size_t start, size_t end) = 0;
184
185 protected:
186 friend class LookupIterator;
187
188 // Element handlers distinguish between entries and indices when they
189 // manipulate elements. Entries refer to elements in terms of their location
190 // in the underlying storage's backing store representation, and are between 0
191 // and GetCapacity. Indices refer to elements in terms of the value that would
192 // be specified in JavaScript to access the element. In most implementations,
193 // indices are equivalent to entries. In the NumberDictionary
194 // ElementsAccessor, entries are mapped to an index using the KeyAt method on
195 // the NumberDictionary.
196 virtual uint32_t GetEntryForIndex(Isolate* isolate, JSObject holder,
197 FixedArrayBase backing_store,
198 uint32_t index) = 0;
199
200 virtual PropertyDetails GetDetails(JSObject holder, uint32_t entry) = 0;
201 virtual void Reconfigure(Handle<JSObject> object,
202 Handle<FixedArrayBase> backing_store, uint32_t entry,
203 Handle<Object> value,
204 PropertyAttributes attributes) = 0;
205
206 // Deletes an element in an object.
207 virtual void Delete(Handle<JSObject> holder, uint32_t entry) = 0;
208
209 // NOTE: this method violates the handlified function signature convention:
210 // raw pointer parameter |source_holder| in the function that allocates.
211 // This is done intentionally to avoid ArrayConcat() builtin performance
212 // degradation.
213 virtual void CopyElements(JSObject source_holder, uint32_t source_start,
214 ElementsKind source_kind,
215 Handle<FixedArrayBase> destination,
216 uint32_t destination_start, int copy_size) = 0;
217
218 private:
219 static ElementsAccessor** elements_accessors_;
220 const char* name_;
221
222 DISALLOW_COPY_AND_ASSIGN(ElementsAccessor);
223};
224
225void CheckArrayAbuse(Handle<JSObject> obj, const char* op, uint32_t index,
226 bool allow_appending = false);
227
228V8_WARN_UNUSED_RESULT MaybeHandle<Object> ArrayConstructInitializeElements(
229 Handle<JSArray> array, Arguments* args);
230
231// Called directly from CSA.
232// {raw_context}: Context pointer.
233// {raw_source}: JSArray pointer.
234// {raw_destination}: JSTypedArray pointer.
235void CopyFastNumberJSArrayElementsToTypedArray(Address raw_context,
236 Address raw_source,
237 Address raw_destination,
238 uintptr_t length,
239 uintptr_t offset);
240// {raw_source}, {raw_destination}: JSTypedArray pointers.
241void CopyTypedArrayElementsToTypedArray(Address raw_source,
242 Address raw_destination,
243 uintptr_t length, uintptr_t offset);
244// {raw_source}, {raw_destination}: JSTypedArray pointers.
245void CopyTypedArrayElementsSlice(Address raw_source, Address raw_destination,
246 uintptr_t start, uintptr_t end);
247
248} // namespace internal
249} // namespace v8
250
251#endif // V8_ELEMENTS_H_
252