Re: callback problem

Hi,
I wonder if you are trying to debug JAWIN. But why you ask such question?
Debug the code! I only want you to have a look at JAWIN design problems.
Its
basic ideas should be revised.
What I am developing now is not a product but only demo. I plan to issue
it
in half a year. I gave you the references to show how such products should
be designed.


Regards,
Vitaly Shelest

"Howard Chivers" <[email protected]> wrote in message
news:LISTSERV%[email protected]...
> (1) Vitaly,
>
> Thanks for your message. I would prefer to contribute to an open-source
> project than buy a commercial alternative; I wish to share freely the
> results of my work.
>
> (2) Anyone else
>
> I should have mentioned in my original post - if I run using the jawin
> debug dll, then no exception is thrown; however, only 5 callbacks are
> made,
> however many should be available.
>
> regards
> Howard
>
>
>
> On Sun, 1 Apr 2007 13:53:46 +0200, Vitaly Shelest
> <[email protected]>
> wrote:
>
>>Hi,
>>some time ago I also tried to use Native Function call implemented in
>>JAWIN
>>but failed. This piece of the project have not been accomplished. They
>>suggest to use explicit marshaling that is not clear for Developer.
> Function
>>calling conventions cdecl, fastcall are not supported (only stdcall).
>>Structure marshal is headache (they do not support union, struct.
>>packing,
>>etc.). The same problems with call of native functions from virtual
>>tables.
>>I also tried to use another projects like xFunctions, JNIWrappers, etc.
>>These projects support complex explicit marshaling makes my code huge
>>and
>>unclear.
>>As a result I started to develop my own API for Native Function Call
>>from
>>Java. Having learnt Platform Invoke in .NET I have realized that the
>>same
>>can be done in SUN/IBM Java. My API implements in Java .NET Platform
>>Invoke
>>paradigm:
>>- implicit and explicit marshaling;
>>- C Structure marshaling;
>>- Java array marshaling;
>>- marshal by value and by reference;
>>- callback functions;
>>- C class functions call from Class Virtual Table, etc.
>>
>>See links:
>>http://www.simtel.net/product.php[id]100916[SiteID]simtel.net
>>http://www.programmersheaven.com/download/51865/download.aspx
>>
>>
>>
>>Regards,
>>Vitaly Shelest,
>>
>>
>>"Howard Chivers" <[email protected]> wrote in message
>>news:LISTSERV%[email protected]...
>>> Hi,
>>>
>>> I've been trying to use jawin to wrap some User32 functions - many
>>> thanks
>>> for the framework & I'll be happy to donate any stubs that result.
>>> However, I'm having problems with callbacks.
>>>
>>> I'd be grateful if anyone could have a quick look at the following; I
>>> think
>>> I've read the source correctly & it seems straightforward, but I'd be
>>> grateful for confirmation.
>>>
>>> The following example wraps the EnumWindows function. Similar problems
>>> occur with other enum functions. The code works correctly, and calls
>>> back
>>> to EnumWindowsProc, passing handles and lparam correctly; after
>>> exactly
>>> 5
>>> callbacks (and with lots more to enumerate) the system throws a
> protection
>>> exception - either protected code or access violation. (A more complex
>>> example with enum child has convinced me that this is not a genuine
>>> security problem).
>>>
>>> It is possible that I have not correctly worked out how to build the
>>> return
>>> from the callback, with the result that the stack is mangled on return
>>> from
>>> callback? or is this likley to be a bug?
>>>
>>> Thanks
>>> Howard
>>>
>>> --------
>>> public void debugEnumWindows() throws COMException, IOException {
>>>        User32_a.EnumWindows(new EnumWindowsProc() {
>>>            public boolean call(int hWnd,int lParam) {
>>>                return true;
>>>                }
>>>           },0x99);
>>>        return;
>>>    }
>>> --------------
>>> public static void EnumWindows(EnumWindowsProc ewp,int lParam) throws
>>> IOException, COMException {
>>>        FuncPtr fp = new FuncPtr("user32.dll","EnumWindows");
>>>        NakedByteStream nbs = new NakedByteStream();
>>>        LittleEndianOutputStream leos = new LittleEndianOutputStream
>>> (nbs);
>>>        leos.writeInt(0);
>>>        leos.writeInt(lParam);
>>>        byte[] res = fp.invoke("T2." + EnumWindowsProc.mtoken + "I::",
>>>                8, nbs, new Object[] {ewp}, ReturnFlags.CHECK_FALSE);
>>>        return;
>>>    }
>>> -----------------
>>>
>>> public abstract class EnumWindowsProc extends WinFuncPtr {
>>>
>>>    public static final int mtoken = GenericStub.registerCustomString
>>> ("2II:I:");
>>>    abstract public boolean call (int hWnd,int lParam) throws
>>> IOException;
>>>
>>>    protected byte[] call(byte[] inargs, Object[] inobjs) throws
>>> IOException {
>>>        LittleEndianInputStream leis = new LittleEndianInputStream(new
>>> ByteArrayInputStream(inargs));
>>>        int hWnd = leis.readInt();
>>>        int lParam = leis.readInt();
>>>        boolean ret = call(hWnd,lParam);
>>>        NakedByteStream nbs = new NakedByteStream();
>>>        LittleEndianOutputStream leos = new
>>> LittleEndianOutputStream(nbs);
>>>        leos.writeInt(ret ? 1 : 0);
>>>        return nbs.getInternalBuffer();
>>>    }
>>> }
>>>
>>>
>>> ----end------
>>>
>



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