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。