Ben Murdoch | 69a99ed | 2011-11-30 16:03:39 +0000 | [diff] [blame^] | 1 | // Copyright 2011 the V8 project authors. All rights reserved. |
| 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" |
| 32 | |
| 33 | namespace v8 { |
| 34 | namespace internal { |
| 35 | |
| 36 | // Abstract base class for handles that can operate on objects with differing |
| 37 | // ElementsKinds. |
| 38 | class ElementsAccessor { |
| 39 | public: |
| 40 | ElementsAccessor() { } |
| 41 | virtual ~ElementsAccessor() { } |
| 42 | virtual MaybeObject* Get(FixedArrayBase* backing_store, |
| 43 | uint32_t key, |
| 44 | JSObject* holder, |
| 45 | Object* receiver) = 0; |
| 46 | |
| 47 | virtual MaybeObject* Delete(JSObject* holder, |
| 48 | uint32_t key, |
| 49 | JSReceiver::DeleteMode mode) = 0; |
| 50 | |
| 51 | virtual MaybeObject* AddElementsToFixedArray(FixedArrayBase* from, |
| 52 | FixedArray* to, |
| 53 | JSObject* holder, |
| 54 | Object* receiver) = 0; |
| 55 | |
| 56 | // Returns a shared ElementsAccessor for the specified ElementsKind. |
| 57 | static ElementsAccessor* ForKind(JSObject::ElementsKind elements_kind) { |
| 58 | ASSERT(elements_kind < JSObject::kElementsKindCount); |
| 59 | return elements_accessors_[elements_kind]; |
| 60 | } |
| 61 | |
| 62 | static ElementsAccessor* ForArray(FixedArrayBase* array); |
| 63 | |
| 64 | static void InitializeOncePerProcess(); |
| 65 | |
| 66 | protected: |
| 67 | friend class NonStrictArgumentsElementsAccessor; |
| 68 | |
| 69 | virtual uint32_t GetCapacity(FixedArrayBase* backing_store) = 0; |
| 70 | |
| 71 | virtual bool HasElementAtIndex(FixedArrayBase* backing_store, |
| 72 | uint32_t index, |
| 73 | JSObject* holder, |
| 74 | Object* receiver) = 0; |
| 75 | |
| 76 | // Element handlers distinguish between indexes and keys when the manipulate |
| 77 | // elements. Indexes refer to elements in terms of their location in the |
| 78 | // underlying storage's backing store representation, and are between 0 |
| 79 | // GetCapacity. Keys refer to elements in terms of the value that would be |
| 80 | // specific in JavaScript to access the element. In most implementations, keys |
| 81 | // are equivalent to indexes, and GetKeyForIndex returns the same value it is |
| 82 | // passed. In the NumberDictionary ElementsAccessor, GetKeyForIndex maps the |
| 83 | // index to a key using the KeyAt method on the NumberDictionary. |
| 84 | virtual uint32_t GetKeyForIndex(FixedArrayBase* backing_store, |
| 85 | uint32_t index) = 0; |
| 86 | |
| 87 | private: |
| 88 | static ElementsAccessor** elements_accessors_; |
| 89 | |
| 90 | DISALLOW_COPY_AND_ASSIGN(ElementsAccessor); |
| 91 | }; |
| 92 | |
| 93 | } } // namespace v8::internal |
| 94 | |
| 95 | #endif // V8_ELEMENTS_H_ |