Home | History | Annotate | Download | only in v8 
      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 "wtf/Assertions.h"
     35 #include <v8.h>
     36 
     37 namespace WebCore {
     38 
     39     class ActiveDOMObject;
     40     class DOMDataStore;
     41     class EventTarget;
     42     class Node;
     43 
     44     static const int v8DOMWrapperTypeIndex = 0;
     45     static const int v8DOMWrapperObjectIndex = 1;
     46     static const int v8DefaultWrapperInternalFieldCount = 2;
     47     static const int v8PrototypeTypeIndex = 0;
     48     static const int v8PrototypeInternalFieldcount = 1;
     49 
     50     static const uint16_t v8DOMNodeClassId = 1;
     51     static const uint16_t v8DOMObjectClassId = 2;
     52 
     53     enum WrapperWorldType {
     54         MainWorld,
     55         IsolatedWorld,
     56         WorkerWorld
     57     };
     58 
     59     typedef v8::Handle<v8::FunctionTemplate> (*GetTemplateFunction)(v8::Isolate*, WrapperWorldType);
     60     typedef void (*DerefObjectFunction)(void*);
     61     typedef ActiveDOMObject* (*ToActiveDOMObjectFunction)(v8::Handle<v8::Object>);
     62     typedef EventTarget* (*ToEventTargetFunction)(v8::Handle<v8::Object>);
     63     typedef void* (*OpaqueRootForGC)(void*, v8::Isolate*);
     64     typedef void (*InstallPerContextPrototypePropertiesFunction)(v8::Handle<v8::Object>, v8::Isolate*);
     65 
     66     enum WrapperTypePrototype {
     67         WrapperTypeObjectPrototype,
     68         WrapperTypeErrorPrototype
     69     };
     70 
     71     // This struct provides a way to store a bunch of information that is helpful when unwrapping
     72     // v8 objects. Each v8 bindings class has exactly one static WrapperTypeInfo member, so
     73     // comparing pointers is a safe way to determine if types match.
     74     struct WrapperTypeInfo {
     75 
     76         static WrapperTypeInfo* unwrap(v8::Handle<v8::Value> typeInfoWrapper)
     77         {
     78             return reinterpret_cast<WrapperTypeInfo*>(v8::External::Cast(*typeInfoWrapper)->Value());
     79         }
     80 
     81 
     82         bool equals(const WrapperTypeInfo* that) const
     83         {
     84             return this == that;
     85         }
     86 
     87         bool isSubclass(const WrapperTypeInfo* that) const
     88         {
     89             for (const WrapperTypeInfo* current = this; current; current = current->parentClass) {
     90                 if (current == that)
     91                     return true;
     92             }
     93 
     94             return false;
     95         }
     96 
     97         v8::Handle<v8::FunctionTemplate> getTemplate(v8::Isolate* isolate, WrapperWorldType worldType) { return getTemplateFunction(isolate, worldType); }
     98 
     99         void derefObject(void* object)
    100         {
    101             if (derefObjectFunction)
    102                 derefObjectFunction(object);
    103         }
    104 
    105         void installPerContextPrototypeProperties(v8::Handle<v8::Object> proto, v8::Isolate* isolate)
    106         {
    107             if (installPerContextPrototypePropertiesFunction)
    108                 installPerContextPrototypePropertiesFunction(proto, isolate);
    109         }
    110 
    111         ActiveDOMObject* toActiveDOMObject(v8::Handle<v8::Object> object)
    112         {
    113             if (!toActiveDOMObjectFunction)
    114                 return 0;
    115             return toActiveDOMObjectFunction(object);
    116         }
    117 
    118         EventTarget* toEventTarget(v8::Handle<v8::Object> object)
    119         {
    120             if (!toEventTargetFunction)
    121                 return 0;
    122             return toEventTargetFunction(object);
    123         }
    124 
    125         void* opaqueRootForGC(void* object, v8::Isolate* isolate)
    126         {
    127             if (!opaqueRootForGCFunction)
    128                 return object;
    129             return opaqueRootForGCFunction(object, isolate);
    130         }
    131 
    132         const GetTemplateFunction getTemplateFunction;
    133         const DerefObjectFunction derefObjectFunction;
    134         const ToActiveDOMObjectFunction toActiveDOMObjectFunction;
    135         const ToEventTargetFunction toEventTargetFunction;
    136         const OpaqueRootForGC opaqueRootForGCFunction;
    137         const InstallPerContextPrototypePropertiesFunction installPerContextPrototypePropertiesFunction;
    138         const WrapperTypeInfo* parentClass;
    139         const WrapperTypePrototype wrapperTypePrototype;
    140     };
    141 
    142     template<typename T, int offset>
    143     inline T* getInternalField(const v8::Persistent<v8::Object>& persistent)
    144     {
    145         // This would be unsafe, but InternalFieldCount and GetAlignedPointerFromInternalField are guaranteed not to allocate
    146         const v8::Handle<v8::Object>& object = reinterpret_cast<const v8::Handle<v8::Object>&>(persistent);
    147         ASSERT(object->InternalFieldCount() >= offset);
    148         return static_cast<T*>(object->GetAlignedPointerFromInternalField(offset));
    149     }
    150 
    151     template<typename T, int offset>
    152     inline T* getInternalField(v8::Handle<v8::Object> object)
    153     {
    154         ASSERT(object->InternalFieldCount() >= offset);
    155         return static_cast<T*>(object->GetAlignedPointerFromInternalField(offset));
    156     }
    157 
    158     inline void* toNative(const v8::Persistent<v8::Object>& object)
    159     {
    160         return getInternalField<void, v8DOMWrapperObjectIndex>(object);
    161     }
    162 
    163     inline void* toNative(v8::Handle<v8::Object> object)
    164     {
    165         return getInternalField<void, v8DOMWrapperObjectIndex>(object);
    166     }
    167 
    168     inline WrapperTypeInfo* toWrapperTypeInfo(const v8::Persistent<v8::Object>& object)
    169     {
    170         return getInternalField<WrapperTypeInfo, v8DOMWrapperTypeIndex>(object);
    171     }
    172 
    173     inline WrapperTypeInfo* toWrapperTypeInfo(v8::Handle<v8::Object> object)
    174     {
    175         return getInternalField<WrapperTypeInfo, v8DOMWrapperTypeIndex>(object);
    176     }
    177 
    178     struct WrapperConfiguration {
    179 
    180         enum Lifetime {
    181             Dependent, Independent
    182         };
    183 
    184         void configureWrapper(v8::Persistent<v8::Object>* wrapper, v8::Isolate* isolate) const
    185         {
    186             wrapper->SetWrapperClassId(isolate, classId);
    187             if (lifetime == Independent)
    188                 wrapper->MarkIndependent(isolate);
    189         }
    190 
    191         const uint16_t classId;
    192         const Lifetime lifetime;
    193     };
    194 
    195     inline WrapperConfiguration buildWrapperConfiguration(void*, WrapperConfiguration::Lifetime lifetime)
    196     {
    197         WrapperConfiguration configuration = {v8DOMObjectClassId, lifetime};
    198         return configuration;
    199     }
    200 
    201     inline WrapperConfiguration buildWrapperConfiguration(Node*, WrapperConfiguration::Lifetime lifetime)
    202     {
    203         WrapperConfiguration configuration = {v8DOMNodeClassId, lifetime};
    204         return configuration;
    205     }
    206 
    207     template<class ElementType>
    208     class WrapperTypeTraits {
    209         // specialized classes have thier own functions, which are generated by binding generator.
    210     };
    211 }
    212 
    213 #endif // WrapperTypeInfo_h
    214