StandardOleMarshalObject.cs

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namespace System.Runtime.InteropServices;
 
public class StandardOleMarshalObject : MarshalByRefObject, IMarshal
{
    [UnmanagedFunctionPointer(CallingConvention.StdCall)]
    private delegate int GetMarshalSizeMaxDelegate(IntPtr _this, ref Guid riid, IntPtr pv, int dwDestContext, IntPtr pvDestContext, int mshlflags, out int pSize);
 
    [UnmanagedFunctionPointer(CallingConvention.StdCall)]
    private delegate int MarshalInterfaceDelegate(IntPtr _this, IntPtr pStm, ref Guid riid, IntPtr pv, int dwDestContext, IntPtr pvDestContext, int mshlflags);
 
    private static readonly Guid CLSID_StdMarshal = new Guid("00000017-0000-0000-c000-000000000046");
 
    protected StandardOleMarshalObject()
    {
    }
 
    private IntPtr GetStdMarshaler(ref Guid riid, int dwDestContext, int mshlflags)
    {
        IntPtr iUnknownForObject = Marshal.GetIUnknownForObject(this);
        if (iUnknownForObject != IntPtr.Zero)
        {
            try
            {
                IntPtr ppMarshal = IntPtr.Zero;
                if (Interop.Ole32.CoGetStandardMarshal(ref riid, iUnknownForObject, dwDestContext, IntPtr.Zero, mshlflags, out ppMarshal) == 0)
                {
                    return ppMarshal;
                }
            }
            finally
            {
                Marshal.Release(iUnknownForObject);
            }
        }
        throw new InvalidOperationException(SR.Format(SR.StandardOleMarshalObjectGetMarshalerFailed, riid));
    }
 
    int IMarshal.GetUnmarshalClass(ref Guid riid, IntPtr pv, int dwDestContext, IntPtr pvDestContext, int mshlflags, out Guid pCid)
    {
        pCid = CLSID_StdMarshal;
        return 0;
    }
 
    unsafe int IMarshal.GetMarshalSizeMax(ref Guid riid, IntPtr pv, int dwDestContext, IntPtr pvDestContext, int mshlflags, out int pSize)
    {
        IntPtr stdMarshaler = GetStdMarshaler(ref riid, dwDestContext, mshlflags);
        try
        {
            IntPtr intPtr = *(IntPtr*)stdMarshaler.ToPointer();
            IntPtr ptr = *(IntPtr*)((byte*)intPtr.ToPointer() + (nint)4 * (nint)sizeof(IntPtr));
            GetMarshalSizeMaxDelegate getMarshalSizeMaxDelegate = (GetMarshalSizeMaxDelegate)Marshal.GetDelegateForFunctionPointer(ptr, typeof(GetMarshalSizeMaxDelegate));
            return getMarshalSizeMaxDelegate(stdMarshaler, ref riid, pv, dwDestContext, pvDestContext, mshlflags, out pSize);
        }
        finally
        {
            Marshal.Release(stdMarshaler);
        }
    }
 
    unsafe int IMarshal.MarshalInterface(IntPtr pStm, ref Guid riid, IntPtr pv, int dwDestContext, IntPtr pvDestContext, int mshlflags)
    {
        IntPtr stdMarshaler = GetStdMarshaler(ref riid, dwDestContext, mshlflags);
        try
        {
            IntPtr intPtr = *(IntPtr*)stdMarshaler.ToPointer();
            IntPtr ptr = *(IntPtr*)((byte*)intPtr.ToPointer() + (nint)5 * (nint)sizeof(IntPtr));
            MarshalInterfaceDelegate marshalInterfaceDelegate = (MarshalInterfaceDelegate)Marshal.GetDelegateForFunctionPointer(ptr, typeof(MarshalInterfaceDelegate));
            return marshalInterfaceDelegate(stdMarshaler, pStm, ref riid, pv, dwDestContext, pvDestContext, mshlflags);
        }
        finally
        {
            Marshal.Release(stdMarshaler);
        }
    }
 
    int IMarshal.UnmarshalInterface(IntPtr pStm, ref Guid riid, out IntPtr ppv)
    {
        ppv = IntPtr.Zero;
        return -2147467263;
    }
 
    int IMarshal.ReleaseMarshalData(IntPtr pStm)
    {
        return -2147467263;
    }
 
    int IMarshal.DisconnectObject(int dwReserved)
    {
        return -2147467263;
    }
}