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1 /* | 1 /* |
2 * Copyright (C) 2010 Google Inc. All rights reserved. | 2 * Copyright (C) 2010 Google Inc. All rights reserved. |
3 * | 3 * |
4 * Redistribution and use in source and binary forms, with or without | 4 * Redistribution and use in source and binary forms, with or without |
5 * modification, are permitted provided that the following conditions are | 5 * modification, are permitted provided that the following conditions are |
6 * met: | 6 * met: |
7 * | 7 * |
8 * * Redistributions of source code must retain the above copyright | 8 * * Redistributions of source code must retain the above copyright |
9 * notice, this list of conditions and the following disclaimer. | 9 * notice, this list of conditions and the following disclaimer. |
10 * * Redistributions in binary form must reproduce the above | 10 * * Redistributions in binary form must reproduce the above |
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31 #ifndef ScriptWrappable_h | 31 #ifndef ScriptWrappable_h |
32 #define ScriptWrappable_h | 32 #define ScriptWrappable_h |
33 | 33 |
34 #include "WebCoreMemoryInstrumentation.h" | 34 #include "WebCoreMemoryInstrumentation.h" |
35 #include <v8.h> | 35 #include <v8.h> |
36 | 36 |
37 namespace WebCore { | 37 namespace WebCore { |
38 | 38 |
39 class ScriptWrappable { | 39 class ScriptWrappable { |
40 public: | 40 public: |
41 ScriptWrappable() | 41 ScriptWrappable() { } |
42 { | |
43 } | |
44 | 42 |
45 v8::Persistent<v8::Object> wrapper() const | 43 v8::Persistent<v8::Object> wrapper() const |
46 { | 44 { |
47 return m_wrapper; | 45 return v8::Persistent<v8::Object>(maskOrUnmaskPointer(*m_maskedWrapper))
; |
48 } | 46 } |
49 | 47 |
50 void setWrapper(v8::Persistent<v8::Object> wrapper) | 48 void setWrapper(v8::Persistent<v8::Object> wrapper) |
51 { | 49 { |
52 ASSERT(!wrapper.IsEmpty()); | 50 m_maskedWrapper = maskOrUnmaskPointer(*wrapper); |
53 m_wrapper = wrapper; | |
54 } | 51 } |
55 | 52 |
56 void clearWrapper() | 53 void clearWrapper() |
57 { | 54 { |
58 ASSERT(!m_wrapper.IsEmpty()); | 55 ASSERT(!m_maskedWrapper.IsEmpty()); |
59 m_wrapper.Clear(); | 56 m_maskedWrapper.Clear(); |
60 } | 57 } |
61 | 58 |
62 void disposeWrapper() | 59 void disposeWrapper() |
63 { | 60 { |
64 ASSERT(!m_wrapper.IsEmpty()); | 61 ASSERT(!m_maskedWrapper.IsEmpty()); |
65 m_wrapper.Dispose(); | 62 m_maskedWrapper = wrapper(); |
66 m_wrapper.Clear(); | 63 m_maskedWrapper.Dispose(); |
| 64 m_maskedWrapper.Clear(); |
67 } | 65 } |
68 | 66 |
69 void reportMemoryUsage(MemoryObjectInfo* memoryObjectInfo) const | 67 void reportMemoryUsage(MemoryObjectInfo* memoryObjectInfo) const |
70 { | 68 { |
71 MemoryClassInfo info(memoryObjectInfo, this, WebCoreMemoryTypes::DOM); | 69 MemoryClassInfo info(memoryObjectInfo, this, WebCoreMemoryTypes::DOM); |
72 info.addWeakPointer(const_cast<v8::Persistent<v8::Object>*>(&m_wrapper))
; | 70 info.addWeakPointer(const_cast<v8::Persistent<v8::Object>*>(&m_maskedWra
pper)); |
73 } | 71 } |
74 | 72 |
75 private: | 73 private: |
76 v8::Persistent<v8::Object> m_wrapper; | 74 v8::Persistent<v8::Object> m_maskedWrapper; |
| 75 |
| 76 static inline v8::Object* maskOrUnmaskPointer(const v8::Object* object) |
| 77 { |
| 78 const uintptr_t objectPointer = reinterpret_cast<uintptr_t>(object); |
| 79 const uintptr_t randomMask = ~(reinterpret_cast<uintptr_t>(&WebCoreMemor
yTypes::DOM) >> 13); // Entropy via ASLR. |
| 80 return reinterpret_cast<v8::Object*>((objectPointer ^ randomMask) & (!ob
jectPointer - 1)); // Preserve null without branching. |
| 81 } |
77 }; | 82 }; |
78 | 83 |
79 } // namespace WebCore | 84 } // namespace WebCore |
80 | 85 |
81 #endif // ScriptWrappable_h | 86 #endif // ScriptWrappable_h |
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