WebKit 学习笔记(5) -- qt javascript 扩展 - 浏览器研究 - ...

jijo 2010-04-21

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WebKit 学习笔记(5) -- qt javascript 扩展收藏
在 QT 目录中打开下面的文件：
\src\3rdparty\webkit\JavaScriptCore\bindings\runtime.cpp

有下面几行：

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#if PLATFORM(QT)
        case Instance::QtLanguage: {
            newInstance = Bindings::QtInstance::getQtInstance((QObject *)nativeInstance, rootObject);
            break;
        }
#endif

#if PLATFORM(QT)
        case Instance::QtLanguage: {
            newInstance = Bindings::QtInstance::getQtInstance((QObject *)nativeInstance, rootObject);
            break;
        }
#endif这就表明，可以用 QtLanguage 来编写自定义的 javascript 对象。这里也有几个别的 Language，也就是说可以用它们来编写扩展 javascript 对象，应该也能自定义自己的 Language。既然是用 qt 的 GUI，使用 QtLanguage 应该是最合适的。

先打开它的例子文件：
\src\3rdparty\webkit\JavaScriptCore\bindings\testqtbindings.cpp

可以看到其中有这样几行：

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static char code[] =
    "myInterface.foo();\n"
    "myInterface.testString = \"Hello\";\n"
    "str = myInterface.testString;\n"
    "myInterface.testInt = 10;\n"
    "i = myInterface.testInt;\n";

static char code[] =
    "myInterface.foo();\n"
    "myInterface.testString = \"Hello\";\n"
    "str = myInterface.testString;\n"
    "myInterface.testInt = 10;\n"
    "i = myInterface.testInt;\n";这就是说，testqtbindings.cpp 的内容可以对下面的 javascript 进行解析：

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myInterface.foo();
myInterface.testString = "Hello";
var str = myInterface.testString;
myInterface.testInt = 10;
var i = myInterface.testInt;

myInterface.foo();
myInterface.testString = "Hello";
var str = myInterface.testString;
myInterface.testInt = 10;
var i = myInterface.testInt;
我想定义自己的 javascript，比如在 myInterface 对象前面加上一个 CSDN 对象：

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CSDN.myInterface.foo();
CSDN.myInterface.testString = "Hello";
var str = CSDN.myInterface.testString;

CSDN.myInterface.foo();
CSDN.myInterface.testString = "Hello";
var str = CSDN.myInterface.testString;
这件事情本来很简单，可是就象 CSDN.myInterface.foo() 这样，连接 CSDN 和 myInterface 两个对象的事情，在网上（中文和英文网站）找了半天没找着，结果还是我自己想到的。

1. 在原来的文件中再添加一个 MyCSDNObject 对象：

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class MyCSDNObject : public QObject
{
    Q_OBJECT
    Q_PROPERTY(QString testString READ testString WRITE setTestString)
    Q_PROPERTY(int testInt READ testInt WRITE setTestInt)
// 添加 QObject 成员作为 CSDN 对象的属性，映射到 testMyInterface 函数上
Q_PROPERTY(QObject* myInterface READ testMyInterface)

public:
    MyCSDNObject() : QObject(0), integer(0), m_myObject(NULL){}

    void setTestString(const QString &str) {
        qDebug() << "called setTestString" << str;
        string = str;
    }
    void setTestInt(int i) {
        qDebug() << "called setTestInt" << i;
        integer = i;
    }
    QString testString() const {
        qDebug() << "called testString" << string;
        return string;
    }
    int testInt() const {
        qDebug() << "called testInt" << integer;
        return integer;
    }
// 在这里返回一个 QObject 对象
QObject *testMyInterface()
{
if (m_myObject == NULL)
   m_myObject = new MyObject();
return m_myObject;
}
    QString string;
    int integer;
// 声名一个 QObject 对象
MyObject *m_myObject;

public slots:
    void foo() { qDebug() << "foo invoked"; }
};

class MyCSDNObject : public QObject
{
    Q_OBJECT
    Q_PROPERTY(QString testString READ testString WRITE setTestString)
    Q_PROPERTY(int testInt READ testInt WRITE setTestInt)
// 添加 QObject 成员作为 CSDN 对象的属性，映射到 testMyInterface 函数上
Q_PROPERTY(QObject* myInterface READ testMyInterface)

public:
MyCSDNObject() : QObject(0), integer(0), m_myObject(NULL){}

    void setTestString(const QString &str) {
        qDebug() << "called setTestString" << str;
        string = str;
    }
    void setTestInt(int i) {
        qDebug() << "called setTestInt" << i;
        integer = i;
    }
    QString testString() const {
        qDebug() << "called testString" << string;
        return string;
    }
    int testInt() const {
        qDebug() << "called testInt" << integer;
        return integer;
    }
// 在这里返回一个 QObject 对象
QObject *testMyInterface()
{
if (m_myObject == NULL)
   m_myObject = new MyObject();
return m_myObject;
}
    QString string;
    int integer;
// 声名一个 QObject 对象
MyObject *m_myObject;

public slots:
void foo() { qDebug() << "foo invoked"; }
};

这样 MyCSDNObject 和 MyObject 这样两个对象就可以连起来了，成为 CSDN.testMyInterface

2. 修改一下创建的根对象的名字

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global->put(exec, Identifier("CSDN"), Instance::createRuntimeObject(Instance::QtLanguage, (void*)myObject));

global->put(exec, Identifier("CSDN"), Instance::createRuntimeObject(Instance::QtLanguage, (void*)myObject));

这样就可以了。这是个测试程序，需要把这些测试代码添加到 WebKit 浏览器中。打开文件：
.\src\3rdparty\webkit\WebKit\qt\Api\qwebframe.h
把刚才的 MyObject 类和 MyCSDNObject 类在其中声名一下，然后添加 CSDN 根对象作为 QWebFrame 类的私有成员，如下所示：

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class MyObject : public QObject
{
    Q_OBJECT
   // 省略 ...
};

class MyCSDNObject : public QObject
{
    Q_OBJECT
    // 省略 ...
};

class QWEBKIT_EXPORT QWebFrame : public QObject
{
    Q_OBJECT
    Q_PROPERTY(qreal textSizeMultiplier READ textSizeMultiplier WRITE setTextSizeMultiplier)
    Q_PROPERTY(QString title READ title)
    Q_PROPERTY(QUrl url READ url WRITE setUrl)
    Q_PROPERTY(QIcon icon READ icon)
    Q_PROPERTY(QSize contentsSize READ contentsSize)
private:
    QWebFrame(QWebPage *parent, QWebFrameData *frameData);
    QWebFrame(QWebFrame *parent, QWebFrameData *frameData);
    ~QWebFrame();

    // 声名 CSDN 根对象
    MyCSDNObject *m_csdn;

    public:
// 以下省略 ...
};

class MyObject : public QObject
{
Q_OBJECT
// 省略 ...
};

class MyCSDNObject : public QObject
{
Q_OBJECT
// 省略 ...
};

class QWEBKIT_EXPORT QWebFrame : public QObject
{
    Q_OBJECT
    Q_PROPERTY(qreal textSizeMultiplier READ textSizeMultiplier WRITE setTextSizeMultiplier)
    Q_PROPERTY(QString title READ title)
    Q_PROPERTY(QUrl url READ url WRITE setUrl)
    Q_PROPERTY(QIcon icon READ icon)
    Q_PROPERTY(QSize contentsSize READ contentsSize)
private:
    QWebFrame(QWebPage *parent, QWebFrameData *frameData);
    QWebFrame(QWebFrame *parent, QWebFrameData *frameData);
    ~QWebFrame();

// 声名 CSDN 根对象
MyCSDNObject *m_csdn;

public:
// 以下省略 ...
};
打开 qwebframe.cpp 文件，在 QWebFrame 的构造函数中创建 CSDN 根对象。

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QWebFrame::QWebFrame(QWebPage *parent, QWebFrameData *frameData)
    : QObject(parent)
    , d(new QWebFramePrivate)
{
    d->page = parent;
    d->init(this, parent->d->page, frameData);

    // 在这里创建 CSDN 根对象
    {
    KJS::Bindings::RootObject *root = d->frame->bindingRootObject();
    KJS::ExecState *exec = root->interpreter()->globalExec();
    KJS::JSObject *global = root->interpreter()->globalObject();

    m_csdn = new MyCSDNObject();
    global->put(exec, KJS::Identifier("CSDN"), KJS::Bindings::Instance::createRuntimeObject(KJS::Bindings::Instance::QtLanguage, (void *)m_csdn, root));
    }

    if (!frameData->url.isEmpty()) {
        ResourceRequest request(frameData->url, frameData->referrer);
        d->frame->loader()->load(request, frameData->name);
    }
}

QWebFrame::QWebFrame(QWebPage *parent, QWebFrameData *frameData)
    : QObject(parent)
    , d(new QWebFramePrivate)
{
    d->page = parent;
    d->init(this, parent->d->page, frameData);

    // 在这里创建 CSDN 根对象
    {
    KJS::Bindings::RootObject *root = d->frame->bindingRootObject();
    KJS::ExecState *exec = root->interpreter()->globalExec();
    KJS::JSObject *global = root->interpreter()->globalObject();

    m_csdn = new MyCSDNObject();
    global->put(exec, KJS::Identifier("CSDN"), KJS::Bindings::Instance::createRuntimeObject(KJS::Bindings::Instance::QtLanguage, (void *)m_csdn, root));
    }

    if (!frameData->url.isEmpty()) {
        ResourceRequest request(frameData->url, frameData->referrer);
        d->frame->loader()->load(request, frameData->name);
    }
} 在 QWebFrame 的析构函数中删除 CSDN 根对象

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QWebFrame::~QWebFrame()
{
    if (d->frame && d->frame->loader() && d->frame->loader()->client())
        static_cast(d->frame->loader()->client())->m_webFrame = 0;

    if (m_csdn)
    {
        delete m_csdn;
        m_csdn = NULL;
    }
    delete d;
}

QWebFrame::~QWebFrame()
{
if (d->frame && d->frame->loader() && d->frame->loader()->client())
static_cast(d->frame->loader()->client())->m_webFrame = 0;

if (m_csdn)
{
  delete m_csdn;
  m_csdn = NULL;
}
    delete d;
}再手工编写一个 HTML 测试页 csdn1.htm，内容如下:

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<html>
<head>
<title> New Document </title>
<script language="JavaScript">

</script>
</head>

<body>
<p><a href="javascript:test();">test qt-webkit javascript</a></p>
<p id="txtMessage"></p>
</body>
</html>

编译并运行 WebKit 浏览器，让它打开刚才的测试页 csdn1.htm，点击上面的 test qt-webkit javascript 链接，可以得到下面的效果：

上面的 Hello QtWebKit JavaScript 就是 javascript 设置的 CSDN.myInterface.testString 内容。

本文来自CSDN博客，转载请标明出处：http://blog.csdn.net/sgnaw/archive/2008/06/07/2519791.aspx