webkit的js对象扩展（二）——binding方式创建自定义对象（多实例）

今天刚好有时间，把创建多实例对象的方法写一下，也就是可以像new Date()一样。关于new操作符有一篇讲的很详细，大家可以先看下http://www.pushiming.com/blog/2009/10/the-new-operator/

了解new操作符后大家应该已经知道，必须有一个构造器才能执行new操作。所以比单实例要多了一个过程，就是要创建构造器，下面我把步骤给贴出来。

以MultiObject为例。

1.添加MultiObject.h文件

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1. #ifndefMultiObject_h
2. #defineMultiObject_h
3. #include<wtf/PassRefPtr.h>
4. #include<wtf/RefCounted.h>
5. #include<wtf/RefPtr.h>
7. namespaceWebCore{
9. classFrame;
10. classString;
12. classMultiObject:publicRefCounted<MultiObject>{
14. public:
15. staticPassRefPtr<MultiObject>create(Frame*frame)
16. {
17. returnadoptRef(newMultiObject(frame));
18. }
20. ~MultiObject();
22. voiddisconnectFrame();
23. Frame*frame()const{returnm_frame;}
25. Stringdescription()const;
26. private:
27. MultiObject(Frame*);
28. Frame*m_frame;
29. };
30. }
32. #endif

2.添加MultiObject.cpp文件

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1. #include"MultiObject.h"
3. #include"PlatformString.h"
5. #include"Frame.h"
6. #include"Page.h"
7. #include"RangerIFrameWidget.h"
8. #include"config.h"
10. namespaceWebCore{
12. MultiObject::MultiObject(Frame*frame)
13. :m_frame(frame)
14. {
15. }
17. MultiObject::~MultiObject()
18. {
19. disconnectFrame();
20. }
22. voidMultiObject::disconnectFrame()
23. {
24. m_frame=0;
25. }
27. StringMultiObject::description()const//对象的属性
28. {
29. return"HelloWorld!";
30. }
31. }

3.添加MultiObject.idl文件

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1. modulewindow{
2. interface[
3. CustomConstructor
4. ]MultiObject{
5. readonlyattributeDOMStringdescription;
6. };
7. }

4.修改DOMWindow.h文件

添加声明如下：

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1. attribute[JSCCustomGetter]MultiObjectConstructorMultiObject;

WebCore/bindings/js

5.添加JSMultiObjectConstructor.h

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1. #ifndef__JSMultiObjectConstructor_h__
2. #define__JSMultiObjectConstructor_h__
4. #include"JSDOMBinding.h"
6. namespaceWebCore{
8. classJSMultiObjectConstructor:publicDOMConstructorObject{
9. public:
10. JSMultiObjectConstructor(JSC::ExecState*,JSDOMGlobalObject*);
11. staticconstJSC::ClassInfos_info;
12. private:
13. virtualJSC::ConstructTypegetConstructData(JSC::ConstructData&);
14. virtualconstJSC::ClassInfo*classInfo()const{return&s_info;}
15. };
17. }//namespaceWebCore
19. #endif//__JSMultiObjectConstructor_h__

6.添加JSMultiObjectConstructor.cpp

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1. #include"config.h"
2. #include"JSMultiObjectConstructor.h"
3. #include"JSMultiObject.h"
4. #include"ScriptExecutionContext.h"
5. #include"MultiObject.h"
6. #include<runtime/Error.h>
7. #include"JSDOMWindowBase.h"
9. usingnamespaceJSC;
11. namespaceWebCore{
13. ASSERT_CLASS_FITS_IN_CELL(JSMultiObjectConstructor);
15. constClassInfoJSMultiObjectConstructor::s_info={"MultiObjectConstructor",0,0,0};
17. JSMultiObjectConstructor::JSMultiObjectConstructor(ExecState*exec,JSDOMGlobalObject*globalObject)
18. :DOMConstructorObject(JSMultiObjectConstructor::createStructure(globalObject->objectPrototype()),globalObject)
19. {
20. putDirect(exec->propertyNames().prototype,JSMultiObjectPrototype::self(exec,globalObject),None);
21. }
23. staticJSObject*constructMultiObject(ExecState*exec,JSObject*constructor,constArgList&)
24. {
25. JSMultiObjectConstructor*jsConstructor=static_cast<JSMultiObjectConstructor*>(constructor);
26. JSDOMWindowBase*window=static_cast<JSDOMWindowBase*>(jsConstructor->globalObject());
27. if(!window||!window->impl()||!window->impl()->frame())
28. returnError::create(exec,ReferenceError,"CannotcreateMultiObject...",-1,-1,UString());
29. RefPtr<MultiObject>MultiObject=MultiObject::create(window->impl()->frame());
30. if(!MultiObject.get())
31. returnError::create(exec,ReferenceError,"NotsupportMultiObject...",-1,-1,UString());
32. returnCREATE_DOM_OBJECT_WRAPPER(exec,jsConstructor->globalObject(),MultiObject,MultiObject.get());
33. }
35. ConstructTypeJSMultiObjectConstructor::getConstructData(ConstructData&constructData)
36. {
37. constructData.native.function=constructMultiObject;
38. returnConstructTypeHost;
39. }
41. }//namespaceWebCore

7.修改JSDOMWindowCustom.cpp

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1. #include"JSMultiObjectConstructor.h"
4. JSValueJSDOMWindow::multiObject(ExecState*exec)const
5. {
6. returngetDOMConstructor<JSMultiObjectConstructor>(exec,this);
7. }

OK，再修改相应的CMakeLists.txt就行了。

注意：头文件包含依据自己的项目。