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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 WrapperTypeInfo_h
32 #define WrapperTypeInfo_h
33 
34 #include "gin/public/wrapper_info.h"
35 #include "wtf/Assertions.h"
36 #include <v8.h>
37 
38 namespace WebCore {
39 
40     class ActiveDOMObject;
41     class DOMDataStore;
42     class EventTarget;
43     class Node;
44 
45     static const int v8DOMWrapperTypeIndex = static_cast<int>(gin::kWrapperInfoIndex);
46     static const int v8DOMWrapperObjectIndex = static_cast<int>(gin::kEncodedValueIndex);
47     static const int v8DefaultWrapperInternalFieldCount = static_cast<int>(gin::kNumberOfInternalFields);
48     static const int v8PrototypeTypeIndex = 0;
49     static const int v8PrototypeInternalFieldcount = 1;
50 
51     static const uint16_t v8DOMNodeClassId = 1;
52     static const uint16_t v8DOMObjectClassId = 2;
53 
54     enum WrapperWorldType {
55         MainWorld,
56         IsolatedWorld,
57         WorkerWorld
58     };
59 
60     typedef v8::Handle<v8::FunctionTemplate> (*DomTemplateFunction)(v8::Isolate*, WrapperWorldType);
61     typedef void (*DerefObjectFunction)(void*);
62     typedef ActiveDOMObject* (*ToActiveDOMObjectFunction)(v8::Handle<v8::Object>);
63     typedef EventTarget* (*ToEventTargetFunction)(v8::Handle<v8::Object>);
64     typedef void (*ResolveWrapperReachabilityFunction)(void*, const v8::Persistent<v8::Object>&, v8::Isolate*);
65     typedef void (*InstallPerContextEnabledPrototypePropertiesFunction)(v8::Handle<v8::Object>, v8::Isolate*);
66 
67     enum WrapperTypePrototype {
68         WrapperTypeObjectPrototype,
69         WrapperTypeErrorPrototype
70     };
71 
setObjectGroup(void * object,const v8::Persistent<v8::Object> & wrapper,v8::Isolate * isolate)72     inline void setObjectGroup(void* object, const v8::Persistent<v8::Object>& wrapper, v8::Isolate* isolate)
73     {
74         isolate->SetObjectGroupId(wrapper, v8::UniqueId(reinterpret_cast<intptr_t>(object)));
75     }
76 
77     // This struct provides a way to store a bunch of information that is helpful when unwrapping
78     // v8 objects. Each v8 bindings class has exactly one static WrapperTypeInfo member, so
79     // comparing pointers is a safe way to determine if types match.
80     struct WrapperTypeInfo {
81 
unwrapWrapperTypeInfo82         static const WrapperTypeInfo* unwrap(v8::Handle<v8::Value> typeInfoWrapper)
83         {
84             return reinterpret_cast<const WrapperTypeInfo*>(v8::External::Cast(*typeInfoWrapper)->Value());
85         }
86 
87 
equalsWrapperTypeInfo88         bool equals(const WrapperTypeInfo* that) const
89         {
90             return this == that;
91         }
92 
isSubclassWrapperTypeInfo93         bool isSubclass(const WrapperTypeInfo* that) const
94         {
95             for (const WrapperTypeInfo* current = this; current; current = current->parentClass) {
96                 if (current == that)
97                     return true;
98             }
99 
100             return false;
101         }
102 
domTemplateWrapperTypeInfo103         v8::Handle<v8::FunctionTemplate> domTemplate(v8::Isolate* isolate, WrapperWorldType worldType) const { return domTemplateFunction(isolate, worldType); }
104 
derefObjectWrapperTypeInfo105         void derefObject(void* object) const
106         {
107             if (derefObjectFunction)
108                 derefObjectFunction(object);
109         }
110 
installPerContextEnabledMethodsWrapperTypeInfo111         void installPerContextEnabledMethods(v8::Handle<v8::Object> prototypeTemplate, v8::Isolate* isolate) const
112         {
113             if (installPerContextEnabledMethodsFunction)
114                 installPerContextEnabledMethodsFunction(prototypeTemplate, isolate);
115         }
116 
toActiveDOMObjectWrapperTypeInfo117         ActiveDOMObject* toActiveDOMObject(v8::Handle<v8::Object> object) const
118         {
119             if (!toActiveDOMObjectFunction)
120                 return 0;
121             return toActiveDOMObjectFunction(object);
122         }
123 
toEventTargetWrapperTypeInfo124         EventTarget* toEventTarget(v8::Handle<v8::Object> object) const
125         {
126             if (!toEventTargetFunction)
127                 return 0;
128             return toEventTargetFunction(object);
129         }
130 
visitDOMWrapperWrapperTypeInfo131         void visitDOMWrapper(void* object, const v8::Persistent<v8::Object>& wrapper, v8::Isolate* isolate) const
132         {
133             if (!visitDOMWrapperFunction)
134                 setObjectGroup(object, wrapper, isolate);
135             else
136                 visitDOMWrapperFunction(object, wrapper, isolate);
137         }
138 
139         // This field must be the first member of the struct WrapperTypeInfo. This is also checked by a COMPILE_ASSERT() below.
140         const gin::GinEmbedder ginEmbedder;
141 
142         const DomTemplateFunction domTemplateFunction;
143         const DerefObjectFunction derefObjectFunction;
144         const ToActiveDOMObjectFunction toActiveDOMObjectFunction;
145         const ToEventTargetFunction toEventTargetFunction;
146         const ResolveWrapperReachabilityFunction visitDOMWrapperFunction;
147         const InstallPerContextEnabledPrototypePropertiesFunction installPerContextEnabledMethodsFunction;
148         const WrapperTypeInfo* parentClass;
149         const WrapperTypePrototype wrapperTypePrototype;
150     };
151 
152 
153     COMPILE_ASSERT(offsetof(struct WrapperTypeInfo, ginEmbedder) == offsetof(struct gin::WrapperInfo, embedder), wrapper_type_info_compatible_to_gin);
154 
155     template<typename T, int offset>
getInternalField(const v8::Persistent<v8::Object> & persistent)156     inline T* getInternalField(const v8::Persistent<v8::Object>& persistent)
157     {
158         // This would be unsafe, but InternalFieldCount and GetAlignedPointerFromInternalField are guaranteed not to allocate
159         const v8::Handle<v8::Object>& object = reinterpret_cast<const v8::Handle<v8::Object>&>(persistent);
160         ASSERT(offset < object->InternalFieldCount());
161         return static_cast<T*>(object->GetAlignedPointerFromInternalField(offset));
162     }
163 
164     template<typename T, int offset>
getInternalField(v8::Handle<v8::Object> object)165     inline T* getInternalField(v8::Handle<v8::Object> object)
166     {
167         ASSERT(offset < object->InternalFieldCount());
168         return static_cast<T*>(object->GetAlignedPointerFromInternalField(offset));
169     }
170 
toNative(const v8::Persistent<v8::Object> & object)171     inline void* toNative(const v8::Persistent<v8::Object>& object)
172     {
173         return getInternalField<void, v8DOMWrapperObjectIndex>(object);
174     }
175 
toNative(v8::Handle<v8::Object> object)176     inline void* toNative(v8::Handle<v8::Object> object)
177     {
178         return getInternalField<void, v8DOMWrapperObjectIndex>(object);
179     }
180 
toWrapperTypeInfo(const v8::Persistent<v8::Object> & object)181     inline const WrapperTypeInfo* toWrapperTypeInfo(const v8::Persistent<v8::Object>& object)
182     {
183         return getInternalField<WrapperTypeInfo, v8DOMWrapperTypeIndex>(object);
184     }
185 
toWrapperTypeInfo(v8::Handle<v8::Object> object)186     inline const WrapperTypeInfo* toWrapperTypeInfo(v8::Handle<v8::Object> object)
187     {
188         return getInternalField<WrapperTypeInfo, v8DOMWrapperTypeIndex>(object);
189     }
190 
191     struct WrapperConfiguration {
192 
193         enum Lifetime {
194             Dependent, Independent
195         };
196 
configureWrapperWrapperConfiguration197         void configureWrapper(v8::Persistent<v8::Object>* wrapper) const
198         {
199             wrapper->SetWrapperClassId(classId);
200             if (lifetime == Independent)
201                 wrapper->MarkIndependent();
202         }
203 
204         const uint16_t classId;
205         const Lifetime lifetime;
206     };
207 
buildWrapperConfiguration(void *,WrapperConfiguration::Lifetime lifetime)208     inline WrapperConfiguration buildWrapperConfiguration(void*, WrapperConfiguration::Lifetime lifetime)
209     {
210         WrapperConfiguration configuration = {v8DOMObjectClassId, lifetime};
211         return configuration;
212     }
213 
buildWrapperConfiguration(Node *,WrapperConfiguration::Lifetime lifetime)214     inline WrapperConfiguration buildWrapperConfiguration(Node*, WrapperConfiguration::Lifetime lifetime)
215     {
216         WrapperConfiguration configuration = {v8DOMNodeClassId, lifetime};
217         return configuration;
218     }
219 
220     template<class ElementType>
221     class WrapperTypeTraits {
222         // specialized classes have thier own functions, which are generated by binding generator.
223     };
224 }
225 
226 #endif // WrapperTypeInfo_h
227