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1 /* | |
2 * Copyright (C) 2010 Google Inc. All rights reserved. | |
3 * | |
4 * Redistribution and use in source and binary forms, with or without | |
5 * modification, are permitted provided that the following conditions are | |
6 * met: | |
7 * | |
8 * * Redistributions of source code must retain the above copyright | |
9 * notice, this list of conditions and the following disclaimer. | |
10 * * Redistributions in binary form must reproduce the above | |
11 * copyright notice, this list of conditions and the following disclaimer | |
12 * in the documentation and/or other materials provided with the | |
13 * distribution. | |
14 * * Neither the name of Google Inc. nor the names of its | |
15 * contributors may be used to endorse or promote products derived from | |
16 * this software without specific prior written permission. | |
17 * | |
18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS | |
19 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT | |
20 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR | |
21 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT | |
22 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, | |
23 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT | |
24 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, | |
25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY | |
26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT | |
27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE | |
28 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | |
29 */ | |
30 | |
31 #ifndef ScriptWrappable_h | |
32 #define ScriptWrappable_h | |
33 | |
34 #include "bindings/v8/WrapperTypeInfo.h" | |
35 #include "platform/heap/Handle.h" | |
36 #include <v8.h> | |
37 | |
38 // Helper to call webCoreInitializeScriptWrappableForInterface in the global nam
espace. | |
39 template <class C> inline void initializeScriptWrappableHelper(C* object) | |
40 { | |
41 void webCoreInitializeScriptWrappableForInterface(C*); | |
42 webCoreInitializeScriptWrappableForInterface(object); | |
43 } | |
44 | |
45 namespace WebCore { | |
46 | |
47 /** | |
48 * ScriptWrappable wraps a V8 object and its WrapperTypeInfo. | |
49 * | |
50 * ScriptWrappable acts much like a v8::Persistent<> in that it keeps a | |
51 * V8 object alive. Under the hood, however, it keeps either a TypeInfo | |
52 * object or an actual v8 persistent (or is empty). | |
53 * | |
54 * The physical state space of ScriptWrappable is: | |
55 * - uintptr_t m_wrapperOrTypeInfo; | |
56 * - if 0: the ScriptWrappable is uninitialized/empty. | |
57 * - if even: a pointer to WebCore::TypeInfo | |
58 * - if odd: a pointer to v8::Persistent<v8::Object> + 1. | |
59 * | |
60 * In other words, one integer represents one of two object pointers, | |
61 * depending on its least signficiant bit, plus an uninitialized state. | |
62 * This class is meant to mask the logistics behind this. | |
63 * | |
64 * typeInfo() and newLocalWrapper will return appropriate values (possibly | |
65 * 0/empty) in all physical states. | |
66 * | |
67 * The state transitions are: | |
68 * - new: an empty and invalid ScriptWrappable. | |
69 * - init (to be called by all subclasses in their constructor): | |
70 * needs to call setTypeInfo | |
71 * - setTypeInfo: install a WrapperTypeInfo | |
72 * - setWrapper: install a v8::Persistent (or empty) | |
73 * - disposeWrapper (via setWeakCallback, triggered by V8 garbage collecter): | |
74 * remove v8::Persistent and install a TypeInfo of the previous value. | |
75 */ | |
76 class ScriptWrappable { | |
77 public: | |
78 ScriptWrappable() : m_wrapperOrTypeInfo(0) { } | |
79 | |
80 // Wrappables need to be initialized with their most derrived type for which | |
81 // bindings exist, in much the same way that certain other types need to be | |
82 // adopted and so forth. The overloaded initializeScriptWrappableForInterfac
e() | |
83 // functions are implemented by the generated V8 bindings code. Declaring th
e | |
84 // extern function in the template avoids making a centralized header of all | |
85 // the bindings in the universe. C++11's extern template feature may provide | |
86 // a cleaner solution someday. | |
87 template <class C> static void init(C* object) | |
88 { | |
89 initializeScriptWrappableHelper(object); | |
90 } | |
91 | |
92 void setWrapper(v8::Handle<v8::Object> wrapper, v8::Isolate* isolate, const
WrapperConfiguration& configuration) | |
93 { | |
94 ASSERT(!containsWrapper()); | |
95 if (!*wrapper) { | |
96 m_wrapperOrTypeInfo = 0; | |
97 return; | |
98 } | |
99 v8::Persistent<v8::Object> persistent(isolate, wrapper); | |
100 configuration.configureWrapper(&persistent); | |
101 persistent.SetWeak(this, &setWeakCallback); | |
102 m_wrapperOrTypeInfo = reinterpret_cast<uintptr_t>(persistent.ClearAndLea
k()) | 1; | |
103 ASSERT(containsWrapper()); | |
104 } | |
105 | |
106 v8::Local<v8::Object> newLocalWrapper(v8::Isolate* isolate) const | |
107 { | |
108 v8::Persistent<v8::Object> persistent; | |
109 getPersistent(&persistent); | |
110 return v8::Local<v8::Object>::New(isolate, persistent); | |
111 } | |
112 | |
113 const WrapperTypeInfo* typeInfo() | |
114 { | |
115 if (containsTypeInfo()) | |
116 return reinterpret_cast<const WrapperTypeInfo*>(m_wrapperOrTypeInfo)
; | |
117 | |
118 if (containsWrapper()) { | |
119 v8::Persistent<v8::Object> persistent; | |
120 getPersistent(&persistent); | |
121 return toWrapperTypeInfo(persistent); | |
122 } | |
123 | |
124 return 0; | |
125 } | |
126 | |
127 void setTypeInfo(const WrapperTypeInfo* typeInfo) | |
128 { | |
129 m_wrapperOrTypeInfo = reinterpret_cast<uintptr_t>(typeInfo); | |
130 ASSERT(containsTypeInfo()); | |
131 } | |
132 | |
133 bool isEqualTo(const v8::Local<v8::Object>& other) const | |
134 { | |
135 v8::Persistent<v8::Object> persistent; | |
136 getPersistent(&persistent); | |
137 return persistent == other; | |
138 } | |
139 | |
140 static bool wrapperCanBeStoredInObject(const void*) { return false; } | |
141 static bool wrapperCanBeStoredInObject(const ScriptWrappable*) { return true
; } | |
142 | |
143 static ScriptWrappable* fromObject(const void*) | |
144 { | |
145 ASSERT_NOT_REACHED(); | |
146 return 0; | |
147 } | |
148 | |
149 static ScriptWrappable* fromObject(ScriptWrappable* object) | |
150 { | |
151 return object; | |
152 } | |
153 | |
154 bool setReturnValue(v8::ReturnValue<v8::Value> returnValue) | |
155 { | |
156 v8::Persistent<v8::Object> persistent; | |
157 getPersistent(&persistent); | |
158 returnValue.Set(persistent); | |
159 return containsWrapper(); | |
160 } | |
161 | |
162 void markAsDependentGroup(ScriptWrappable* groupRoot, v8::Isolate* isolate) | |
163 { | |
164 ASSERT(containsWrapper()); | |
165 ASSERT(groupRoot && groupRoot->containsWrapper()); | |
166 | |
167 v8::UniqueId groupId(groupRoot->m_wrapperOrTypeInfo); | |
168 v8::Persistent<v8::Object> wrapper; | |
169 getPersistent(&wrapper); | |
170 wrapper.MarkPartiallyDependent(); | |
171 isolate->SetObjectGroupId(v8::Persistent<v8::Value>::Cast(wrapper), grou
pId); | |
172 } | |
173 | |
174 void setReference(const v8::Persistent<v8::Object>& parent, v8::Isolate* iso
late) | |
175 { | |
176 v8::Persistent<v8::Object> persistent; | |
177 getPersistent(&persistent); | |
178 isolate->SetReference(parent, persistent); | |
179 } | |
180 | |
181 template<typename V8T, typename T> | |
182 static void assertWrapperSanity(v8::Local<v8::Object> object, T* objectAsT) | |
183 { | |
184 ASSERT(objectAsT); | |
185 RELEASE_ASSERT_WITH_SECURITY_IMPLICATION(object.IsEmpty() | |
186 || object->GetAlignedPointerFromInternalField(v8DOMWrapperObjectInde
x) == V8T::toInternalPointer(objectAsT)); | |
187 } | |
188 | |
189 template<typename V8T, typename T> | |
190 static void assertWrapperSanity(void* object, T* objectAsT) | |
191 { | |
192 ASSERT_NOT_REACHED(); | |
193 } | |
194 | |
195 template<typename V8T, typename T> | |
196 static void assertWrapperSanity(ScriptWrappable* object, T* objectAsT) | |
197 { | |
198 ASSERT(object); | |
199 ASSERT(objectAsT); | |
200 v8::Object* value = object->getRawValue(); | |
201 RELEASE_ASSERT_WITH_SECURITY_IMPLICATION(value == 0 | |
202 || value->GetAlignedPointerFromInternalField(v8DOMWrapperObjectIndex
) == V8T::toInternalPointer(objectAsT)); | |
203 } | |
204 | |
205 inline bool containsWrapper() const { return (m_wrapperOrTypeInfo & 1); } | |
206 inline bool containsTypeInfo() const { return m_wrapperOrTypeInfo && !(m_wra
pperOrTypeInfo & 1); } | |
207 | |
208 protected: | |
209 ~ScriptWrappable() | |
210 { | |
211 // We must not get deleted as long as we contain a wrapper. If this happ
ens, we screwed up ref | |
212 // counting somewhere. Crash here instead of crashing during a later gc
cycle. | |
213 RELEASE_ASSERT_WITH_SECURITY_IMPLICATION(!containsWrapper()); | |
214 ASSERT(m_wrapperOrTypeInfo); // Assert initialization via init() even if
not subsequently wrapped. | |
215 m_wrapperOrTypeInfo = 0; // Break UAF attempts to wrap. | |
216 } | |
217 | |
218 private: | |
219 void getPersistent(v8::Persistent<v8::Object>* persistent) const | |
220 { | |
221 ASSERT(persistent); | |
222 | |
223 // Horrible and super unsafe: Cast the Persistent to an Object*, so | |
224 // that we can inject the wrapped value. This only works because | |
225 // we previously 'stole' the object pointer from a Persistent in | |
226 // the setWrapper() method. | |
227 *reinterpret_cast<v8::Object**>(persistent) = getRawValue(); | |
228 } | |
229 | |
230 inline v8::Object* getRawValue() const | |
231 { | |
232 v8::Object* object = containsWrapper() ? reinterpret_cast<v8::Object*>(m
_wrapperOrTypeInfo & ~1) : 0; | |
233 return object; | |
234 } | |
235 | |
236 inline void disposeWrapper(v8::Local<v8::Object> wrapper) | |
237 { | |
238 ASSERT(containsWrapper()); | |
239 | |
240 v8::Persistent<v8::Object> persistent; | |
241 getPersistent(&persistent); | |
242 | |
243 ASSERT(wrapper == persistent); | |
244 persistent.Reset(); | |
245 setTypeInfo(toWrapperTypeInfo(wrapper)); | |
246 } | |
247 | |
248 // If zero, then this contains nothing, otherwise: | |
249 // If the bottom bit it set, then this contains a pointer to a wrapper obj
ect in the remainging bits. | |
250 // If the bottom bit is clear, then this contains a pointer to the wrapper
type info in the remaining bits. | |
251 uintptr_t m_wrapperOrTypeInfo; | |
252 | |
253 static void setWeakCallback(const v8::WeakCallbackData<v8::Object, ScriptWra
ppable>& data) | |
254 { | |
255 v8::Persistent<v8::Object> persistent; | |
256 data.GetParameter()->getPersistent(&persistent); | |
257 ASSERT(persistent == data.GetValue()); | |
258 data.GetParameter()->disposeWrapper(data.GetValue()); | |
259 | |
260 // FIXME: I noticed that 50%~ of minor GC cycle times can be consumed | |
261 // inside data.GetParameter()->deref(), which causes Node destructions.
We should | |
262 // make Node destructions incremental. | |
263 releaseObject(data.GetValue()); | |
264 } | |
265 }; | |
266 | |
267 } // namespace WebCore | |
268 | |
269 #endif // ScriptWrappable_h | |
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