Ben Murdoch | 3ef787d | 2012-04-12 10:51:47 +0100 | [diff] [blame^] | 1 | // Copyright 2012 the V8 project authors. All rights reserved. |
Ben Murdoch | 69a99ed | 2011-11-30 16:03:39 +0000 | [diff] [blame] | 2 | // Redistribution and use in source and binary forms, with or without |
| 3 | // modification, are permitted provided that the following conditions are |
| 4 | // met: |
| 5 | // |
| 6 | // * Redistributions of source code must retain the above copyright |
| 7 | // notice, this list of conditions and the following disclaimer. |
| 8 | // * Redistributions in binary form must reproduce the above |
| 9 | // copyright notice, this list of conditions and the following |
| 10 | // disclaimer in the documentation and/or other materials provided |
| 11 | // with the distribution. |
| 12 | // * Neither the name of Google Inc. nor the names of its |
| 13 | // contributors may be used to endorse or promote products derived |
| 14 | // from this software without specific prior written permission. |
| 15 | // |
| 16 | // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| 17 | // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| 18 | // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
| 19 | // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
| 20 | // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| 21 | // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
| 22 | // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| 23 | // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| 24 | // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| 25 | // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
| 26 | // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| 27 | |
| 28 | #ifndef V8_ELEMENTS_H_ |
| 29 | #define V8_ELEMENTS_H_ |
| 30 | |
| 31 | #include "objects.h" |
Ben Murdoch | 3ef787d | 2012-04-12 10:51:47 +0100 | [diff] [blame^] | 32 | #include "heap.h" |
| 33 | #include "isolate.h" |
Ben Murdoch | 69a99ed | 2011-11-30 16:03:39 +0000 | [diff] [blame] | 34 | |
| 35 | namespace v8 { |
| 36 | namespace internal { |
| 37 | |
| 38 | // Abstract base class for handles that can operate on objects with differing |
| 39 | // ElementsKinds. |
| 40 | class ElementsAccessor { |
| 41 | public: |
Ben Murdoch | 3ef787d | 2012-04-12 10:51:47 +0100 | [diff] [blame^] | 42 | explicit ElementsAccessor(const char* name) : name_(name) { } |
Ben Murdoch | 69a99ed | 2011-11-30 16:03:39 +0000 | [diff] [blame] | 43 | virtual ~ElementsAccessor() { } |
Ben Murdoch | 69a99ed | 2011-11-30 16:03:39 +0000 | [diff] [blame] | 44 | |
Ben Murdoch | 3ef787d | 2012-04-12 10:51:47 +0100 | [diff] [blame^] | 45 | virtual ElementsKind kind() const = 0; |
| 46 | const char* name() const { return name_; } |
| 47 | |
| 48 | // Returns true if a holder contains an element with the specified key |
| 49 | // without iterating up the prototype chain. The caller can optionally pass |
| 50 | // in the backing store to use for the check, which must be compatible with |
| 51 | // the ElementsKind of the ElementsAccessor. If backing_store is NULL, the |
| 52 | // holder->elements() is used as the backing store. |
| 53 | virtual bool HasElement(Object* receiver, |
| 54 | JSObject* holder, |
| 55 | uint32_t key, |
| 56 | FixedArrayBase* backing_store = NULL) = 0; |
| 57 | |
| 58 | // Returns the element with the specified key or undefined if there is no such |
| 59 | // element. This method doesn't iterate up the prototype chain. The caller |
| 60 | // can optionally pass in the backing store to use for the check, which must |
| 61 | // be compatible with the ElementsKind of the ElementsAccessor. If |
| 62 | // backing_store is NULL, the holder->elements() is used as the backing store. |
| 63 | virtual MaybeObject* Get(Object* receiver, |
| 64 | JSObject* holder, |
| 65 | uint32_t key, |
| 66 | FixedArrayBase* backing_store = NULL) = 0; |
| 67 | |
| 68 | // Modifies the length data property as specified for JSArrays and resizes the |
| 69 | // underlying backing store accordingly. The method honors the semantics of |
| 70 | // changing array sizes as defined in EcmaScript 5.1 15.4.5.2, i.e. array that |
| 71 | // have non-deletable elements can only be shrunk to the size of highest |
| 72 | // element that is non-deletable. |
| 73 | virtual MaybeObject* SetLength(JSArray* holder, |
| 74 | Object* new_length) = 0; |
| 75 | |
| 76 | // Modifies both the length and capacity of a JSArray, resizing the underlying |
| 77 | // backing store as necessary. This method does NOT honor the semantics of |
| 78 | // EcmaScript 5.1 15.4.5.2, arrays can be shrunk beyond non-deletable |
| 79 | // elements. This method should only be called for array expansion OR by |
| 80 | // runtime JavaScript code that use InternalArrays and don't care about |
| 81 | // EcmaScript 5.1 semantics. |
| 82 | virtual MaybeObject* SetCapacityAndLength(JSArray* array, |
| 83 | int capacity, |
| 84 | int length) = 0; |
| 85 | |
| 86 | // Deletes an element in an object, returning a new elements backing store. |
Ben Murdoch | 69a99ed | 2011-11-30 16:03:39 +0000 | [diff] [blame] | 87 | virtual MaybeObject* Delete(JSObject* holder, |
| 88 | uint32_t key, |
| 89 | JSReceiver::DeleteMode mode) = 0; |
| 90 | |
Ben Murdoch | 3ef787d | 2012-04-12 10:51:47 +0100 | [diff] [blame^] | 91 | // If kCopyToEnd is specified as the copy_size to CopyElements, it copies all |
| 92 | // of elements from source after source_start to the destination array. |
| 93 | static const int kCopyToEnd = -1; |
| 94 | // If kCopyToEndAndInitializeToHole is specified as the copy_size to |
| 95 | // CopyElements, it copies all of elements from source after source_start to |
| 96 | // destination array, padding any remaining uninitialized elements in the |
| 97 | // destination array with the hole. |
| 98 | static const int kCopyToEndAndInitializeToHole = -2; |
| 99 | |
| 100 | // Copy elements from one backing store to another. Typically, callers specify |
| 101 | // the source JSObject or JSArray in source_holder. If the holder's backing |
| 102 | // store is available, it can be passed in source and source_holder is |
| 103 | // ignored. |
| 104 | virtual MaybeObject* CopyElements(JSObject* source_holder, |
| 105 | uint32_t source_start, |
| 106 | FixedArrayBase* destination, |
| 107 | ElementsKind destination_kind, |
| 108 | uint32_t destination_start, |
| 109 | int copy_size, |
| 110 | FixedArrayBase* source = NULL) = 0; |
| 111 | |
| 112 | MaybeObject* CopyElements(JSObject* from_holder, |
| 113 | FixedArrayBase* to, |
| 114 | ElementsKind to_kind, |
| 115 | FixedArrayBase* from = NULL) { |
| 116 | return CopyElements(from_holder, 0, to, to_kind, 0, |
| 117 | kCopyToEndAndInitializeToHole, from); |
| 118 | } |
| 119 | |
| 120 | virtual MaybeObject* AddElementsToFixedArray(Object* receiver, |
Ben Murdoch | 85b7179 | 2012-04-11 18:30:58 +0100 | [diff] [blame] | 121 | JSObject* holder, |
Ben Murdoch | 3ef787d | 2012-04-12 10:51:47 +0100 | [diff] [blame^] | 122 | FixedArray* to, |
| 123 | FixedArrayBase* from = NULL) = 0; |
Ben Murdoch | 69a99ed | 2011-11-30 16:03:39 +0000 | [diff] [blame] | 124 | |
| 125 | // Returns a shared ElementsAccessor for the specified ElementsKind. |
Ben Murdoch | 589d697 | 2011-11-30 16:04:58 +0000 | [diff] [blame] | 126 | static ElementsAccessor* ForKind(ElementsKind elements_kind) { |
| 127 | ASSERT(elements_kind < kElementsKindCount); |
Ben Murdoch | 69a99ed | 2011-11-30 16:03:39 +0000 | [diff] [blame] | 128 | return elements_accessors_[elements_kind]; |
| 129 | } |
| 130 | |
| 131 | static ElementsAccessor* ForArray(FixedArrayBase* array); |
| 132 | |
| 133 | static void InitializeOncePerProcess(); |
| 134 | |
| 135 | protected: |
| 136 | friend class NonStrictArgumentsElementsAccessor; |
| 137 | |
| 138 | virtual uint32_t GetCapacity(FixedArrayBase* backing_store) = 0; |
| 139 | |
Ben Murdoch | 3ef787d | 2012-04-12 10:51:47 +0100 | [diff] [blame^] | 140 | // Element handlers distinguish between indexes and keys when they manipulate |
Ben Murdoch | 69a99ed | 2011-11-30 16:03:39 +0000 | [diff] [blame] | 141 | // elements. Indexes refer to elements in terms of their location in the |
Ben Murdoch | 3ef787d | 2012-04-12 10:51:47 +0100 | [diff] [blame^] | 142 | // underlying storage's backing store representation, and are between 0 and |
Ben Murdoch | 69a99ed | 2011-11-30 16:03:39 +0000 | [diff] [blame] | 143 | // GetCapacity. Keys refer to elements in terms of the value that would be |
Ben Murdoch | 3ef787d | 2012-04-12 10:51:47 +0100 | [diff] [blame^] | 144 | // specified in JavaScript to access the element. In most implementations, |
| 145 | // keys are equivalent to indexes, and GetKeyForIndex returns the same value |
| 146 | // it is passed. In the NumberDictionary ElementsAccessor, GetKeyForIndex maps |
| 147 | // the index to a key using the KeyAt method on the NumberDictionary. |
Ben Murdoch | 69a99ed | 2011-11-30 16:03:39 +0000 | [diff] [blame] | 148 | virtual uint32_t GetKeyForIndex(FixedArrayBase* backing_store, |
| 149 | uint32_t index) = 0; |
| 150 | |
| 151 | private: |
| 152 | static ElementsAccessor** elements_accessors_; |
Ben Murdoch | 3ef787d | 2012-04-12 10:51:47 +0100 | [diff] [blame^] | 153 | const char* name_; |
Ben Murdoch | 69a99ed | 2011-11-30 16:03:39 +0000 | [diff] [blame] | 154 | |
| 155 | DISALLOW_COPY_AND_ASSIGN(ElementsAccessor); |
| 156 | }; |
| 157 | |
Ben Murdoch | 3ef787d | 2012-04-12 10:51:47 +0100 | [diff] [blame^] | 158 | |
| 159 | void CopyObjectToObjectElements(FixedArray* from_obj, |
| 160 | ElementsKind from_kind, |
| 161 | uint32_t from_start, |
| 162 | FixedArray* to_obj, |
| 163 | ElementsKind to_kind, |
| 164 | uint32_t to_start, |
| 165 | int copy_size); |
| 166 | |
| 167 | |
Ben Murdoch | 69a99ed | 2011-11-30 16:03:39 +0000 | [diff] [blame] | 168 | } } // namespace v8::internal |
| 169 | |
| 170 | #endif // V8_ELEMENTS_H_ |