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

 #ifndefMultiObject_h
 #defineMultiObject_h
 #include<wtf/PassRefPtr.h>
 #include<wtf/RefCounted.h>
 #include<wtf/RefPtr.h>

 namespaceWebCore{

 classFrame;
 classString;

 classMultiObject:publicRefCounted<MultiObject>{

 public:
 staticPassRefPtr<MultiObject>create(Frame*frame)
 {
 returnadoptRef(newMultiObject(frame));
 }

 ~MultiObject();

 voiddisconnectFrame();
 Frame*frame()const{returnm_frame;}

 Stringdescription()const;
 private:
 MultiObject(Frame*);
 Frame*m_frame;
 };
 }

 #endif

2.添加MultiObject.cpp文件

 #include"MultiObject.h"

 #include"PlatformString.h"

 #include"Frame.h"
 #include"Page.h"
 #include"RangerIFrameWidget.h"
 #include"config.h"

 namespaceWebCore{

 MultiObject::MultiObject(Frame*frame)
 :m_frame(frame)
 {
 }

 MultiObject::~MultiObject()
 {
 disconnectFrame();
 }

 voidMultiObject::disconnectFrame()
 {
 m_frame=0;
 }

 StringMultiObject::description()const//对象的属性
 {
 return"HelloWorld!";
 }
 }

3.添加MultiObject.idl文件

 modulewindow{
 interface[
 CustomConstructor
 ]MultiObject{
 readonlyattributeDOMStringdescription;
 };
 }

4.修改DOMWindow.h文件

添加声明如下：

 attribute[JSCCustomGetter]MultiObjectConstructorMultiObject;

WebCore/bindings/js

5.添加JSMultiObjectConstructor.h

 #ifndef__JSMultiObjectConstructor_h__
 #define__JSMultiObjectConstructor_h__

 #include"JSDOMBinding.h"

 namespaceWebCore{

 classJSMultiObjectConstructor:publicDOMConstructorObject{
 public:
 JSMultiObjectConstructor(JSC::ExecState*,JSDOMGlobalObject*);
 staticconstJSC::ClassInfos_info;
 private:
 virtualJSC::ConstructTypegetConstructData(JSC::ConstructData&);
 virtualconstJSC::ClassInfo*classInfo()const{return&s_info;}
 };

 }//namespaceWebCore

 #endif//__JSMultiObjectConstructor_h__

6.添加JSMultiObjectConstructor.cpp

 #include"config.h"
 #include"JSMultiObjectConstructor.h"
 #include"JSMultiObject.h"
 #include"ScriptExecutionContext.h"
 #include"MultiObject.h"
 #include<runtime/Error.h>
 #include"JSDOMWindowBase.h"

 usingnamespaceJSC;

 namespaceWebCore{

 ASSERT_CLASS_FITS_IN_CELL(JSMultiObjectConstructor);

 constClassInfoJSMultiObjectConstructor::s_info={"MultiObjectConstructor",0,0,0};

 JSMultiObjectConstructor::JSMultiObjectConstructor(ExecState*exec,JSDOMGlobalObject*globalObject)
 :DOMConstructorObject(JSMultiObjectConstructor::createStructure(globalObject->objectPrototype()),globalObject)
 {
 putDirect(exec->propertyNames().prototype,JSMultiObjectPrototype::self(exec,globalObject),None);
 }

 staticJSObject*constructMultiObject(ExecState*exec,JSObject*constructor,constArgList&)
 {
 JSMultiObjectConstructor*jsConstructor=static_cast<JSMultiObjectConstructor*>(constructor);
 JSDOMWindowBase*window=static_cast<JSDOMWindowBase*>(jsConstructor->globalObject());
 if(!window||!window->impl()||!window->impl()->frame())
 returnError::create(exec,ReferenceError,"CannotcreateMultiObject...",-1,-1,UString());
 RefPtr<MultiObject>MultiObject=MultiObject::create(window->impl()->frame());
 if(!MultiObject.get())
 returnError::create(exec,ReferenceError,"NotsupportMultiObject...",-1,-1,UString());
 returnCREATE_DOM_OBJECT_WRAPPER(exec,jsConstructor->globalObject(),MultiObject,MultiObject.get());
 }

 ConstructTypeJSMultiObjectConstructor::getConstructData(ConstructData&constructData)
 {
 constructData.native.function=constructMultiObject;
 returnConstructTypeHost;
 }

 }//namespaceWebCore

7.修改JSDOMWindowCustom.cpp

 #include"JSMultiObjectConstructor.h"


 JSValueJSDOMWindow::multiObject(ExecState*exec)const
 {
 returngetDOMConstructor<JSMultiObjectConstructor>(exec,this);
 }

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。