[Qt-interest] JavaScript persistent execution context?

[noam.rosenthal at nokia.com]

Hi Sherzod

Sounds to me like what you are looking for is the concept of activation object and a global object.
In Webkit, when you execute scripts in a script tag, they are executed in an activation object that is always available.

To make objects persist, they have to be somehow connected to the global object. 

If you want to emulate the behavior of QWebFrame, you should do something like

c++:
scriptEngine->globalObject().setProperty("myObj", pointerToMyObject)

js:
function myAlert()  {}
myObj.jingleJingle.connect(myAlert);

I hope this answers your question - if not, please read and experiment with QScriptContext::activationObject and QScriptEngine::globalObject.

No'am
________________________________________
From: qt-interest-bounces at trolltech.com [qt-interest-bounces at trolltech.com] On Behalf Of ext sherzod_ [sherzod.l at mail.ru]
Sent: Sunday, October 10, 2010 1:37 PM
To: qt-interest at trolltech.com
Subject: Re: [Qt-interest] JavaScript persistent execution context?

Hello No'am.

Thank you for reply.

No I don't use QWebFrame. I just want to emulate it's behaviour. To say more
precisely some of the properties of it's behaviour. To say yet more
precisely the persistent nature of QWebFrame's JS engine context.

For example let's take any JS code that consists of several functions and
some main function as an entry point. I just want to connect some c++ signal
to any of these functions, for example to someNiceAlert(msg), signal is
async and i don't know when it'll be emitted. If we place the following code
into a QWebFrame's <script> element - it's ok. I can emit my signal whenever
i want and it'll work, i'll see my nice alert. But the issue is to make it
without using QWebFrame.

Why i don't use just something like qScriptConnect or mediate functions.
Because i don't need all the code to be executed. Let's assume it's a
library and i just want to use a function from it.

// --------------- js code ------------------------

function someFunc1()
{
        DoSomething();
}

function someNiceAlert(msg)
{
        showIncredibleAlert(msg);
}

function someFunc2()
{
        DoSomethingElse();
}

function SomeFunc3()
        DoSomethingThird();
}

function init() // entry point
{
        someFunc1();
        someFunc2();

        return true;
}

init();

// ----------- end of js code --------------------

noam.rosenthal at nokia.com wrote:

> Hello Sherzod
>
> Is this in QWebFrame or in QtScript? Do you actually have a web-page? How
> do you currently initialize your context? Can you post some initialization
> C++ code here?
>
> In general I'm guessing that the answer to your problem would be to add
> those functions to a global object, e.g. in webkit: instead of
>
> function wakeUp() { ... }
>
> write
>
> window.wakeUp = function() { ... };
>
> But I'm not sure I'm answering the right question...
>
> No'am
>
> ________________________________________
> From: qt-interest-bounces at trolltech.com
> [qt-interest-bounces at trolltech.com] On Behalf Of ext sherzod_
> [sherzod.l at mail.ru] Sent: Wednesday, October 06, 2010 9:11 AM To:
> qt-interest at trolltech.com Subject: [Qt-interest] JavaScript persistent
> execution context?
>
> Hello.
>
> How do I create persistent JavaScript execution context. For example I
> connect a function defined in JS code to a qt c++ signal. I need this
> function to be called even after running out the JS code.
>
> In other words i need a signal-slot connection created in a script to stay
> alive after leaving script context, and surely clear this context maybe
> manually later.
>
> // --------------------------------------------------
>         c++
> // --------------------------------------------------
> ...
>
> SomeQtObject: public QObject
> {
>         ...
>
>         signals:
>                 void jingleJingle();
>
>         ...
> };
>
>
> // --------------------------------------------------
>         javascript
> // --------------------------------------------------
>
> ...
>
> function wakeUp()
> {
>         alert("wake up!");
> }
>
> function run()
> {
>         // SomeQtObject injected as myObj
>
>         myObj.jingleJingle.connect(wakeUp);
>         // need this connection after quitting this code
> }
>
> run();
>
> // --------------------------------------------------
>
> Thanks.
>
> ps. QWebFrame is the example of such behaviour. Web pages script context
> is persistent during livetime of it.
>
> _______________________________________________
> Qt-interest mailing list
> Qt-interest at trolltech.com
> http://lists.trolltech.com/mailman/listinfo/qt-interest

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