[Kde-bindings] [Bug 268463] New: Qyoto delegate marshalling fails in Signals/Slots

[Ilmar Kruis]

https://bugs.kde.org/show_bug.cgi?id=268463

           Summary: Qyoto delegate marshalling fails in Signals/Slots
           Product: bindings
           Version: unspecified
          Platform: Compiled Sources
        OS/Version: MS Windows
            Status: UNCONFIRMED
          Severity: normal
          Priority: NOR
         Component: general
        AssignedTo: kde-bindings at kde.org
        ReportedBy: ikruis at gmail.com


Version:           unspecified (using Devel) 
OS:                MS Windows

Binding delegates to Qyoto slots often failed for me. Recently recompiled for
.NET 4 and the Managed Debugging Assistant pointed me to the following
problems:

- The Extern functions in QObjectExtras.cs don't have a CallingConvention
specified, defaults to the wrong __stdcall on Windows.
- In C# code, the delegate is 'set' with ConnectDelegate, then stored as
Function pointer in C. When it is invoked, InvokeDelegate will create a new
delegate from that function pointer. .NET requires a fully defined delegate
type instead of the general Delegate for this.

The first issue is easily solved, the second I solved for me by changing
delegateinvocation.h to pass the GCHandle instead of the function pointer:
    int qt_metacall(QMetaObject::Call call, int id, void **a)
    {
        id = QObject::qt_metacall(call, id, a);
        if (id < 0)
            return id;

        if (call == QMetaObject::InvokeMetaMethod) {
            if (id == 0) {
                smokeStackFromQtStack(_stack, a + 1, 0, _items, _mocargs);
                next();
                (*InvokeDelegate)(_handle, _sp);
            }
            --id;
        }
        return id;
     }

And SmokeInvocation.cs to accept it and find the delegate linked to it:

static public void InvokeDelegate(IntPtr _d, IntPtr stack) {
  Delegate d = (Delegate)GCHandle.FromIntPtr(_d).Target;
  unsafe { 

Reproducible: Sometimes

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