Error Running jextract on d3d12.h

[Ty Young]

Not a JDK developer, but if you want to do this by hand(aka no 
jextract), I had to do this for NVAPI which obfuscates function pointers 
using keys, e.g.:


nvapi_h.nvapi_QueryInterface(0x0150e828);


where "0x0150e828" is the "NvAPI_Initialize" function key as per the 
Open Source headers Nvidia released sometime ago.


The only difference is that, since the function pointer is in a struct, 
you need to get the segment in the struct containing the function 
pointer(see "slice" MemorySegment method) and actually read from it 
using a VarHandle. You then take that MemoryAddress, with a 
FunctionDescriptor and MethodType, and create a MethodHandle. For 
reference, this my working code("NativeFunction" and "NativeTypes" do 
not exist in Panama, those are mine but they dont matter) for the 
NvAPI_Initalize API:


public class NvAPI_Initialize implements NativeFunction
{
     private final MemoryAddress address;
     private final FunctionDescriptor descriptor;
     private final MethodType type;

     private final MethodHandle handle;

     public NvAPI_Initialize() throws NoSuchMethodException, Throwable
     {
         this.address = nvapi_h.nvapi_QueryInterface(0x0150e828);

         this.descriptor = FunctionDescriptor.of(NativeTypes.INT);

         this.type = MethodType.methodType(int.class);

         this.handle = 
CSupport.getSystemLinker().downcallHandle(this.address, this.type, 
this.descriptor);
     }

     // etc

}


It looks like in your case the FunctionDescriptor would be:


this.descriptor = FunctionDescriptor.of(CSupport.C_POINTER, 
CSupport.C_INT, CSupport.C_POINTER);


for MethodType:


MethodType.methodType(MemoryAddress.class, int.class, MemoryAddress.class);


where the first argument takes in a IDXGIFactory, the second an unsigned 
int, and the third a pointer to what looks like an opaque device that 
you pass to other functions.


If you haven't already, it might help to make bindings with a smaller, 
less complicated library just to get a feel with how things work under 
the hood.


Hope this helps.


On 9/12/20 2:23 AM, Michael Ennen wrote:
> Looking into this a bit further I think I chose a really bad library to
> start with as the function I need to call, EnumAdapters, is inside
> some type of "VTbl" struct that is trying to emulate a C++ class with
> virtual functions. What jextract is returning is most likely *correct*
> but in this case so complicated because of how it is laid out in C. It is
> not clear at all how to grab the EnumAdapters function from
> this mess, and it is probably above my head.
>
> EXTERN_C const IID IID_IDXGIFactory;
>
> #if defined(__cplusplus) && !defined(CINTERFACE)
>
>      MIDL_INTERFACE("7b7166ec-21c7-44ae-b21a-c9ae321ae369")
>      IDXGIFactory : public IDXGIObject
>      {
>      public:
>          virtual HRESULT STDMETHODCALLTYPE EnumAdapters(
>              /* [in] */ UINT Adapter,
>              /* [annotation][out] */
>              _COM_Outptr_  IDXGIAdapter **ppAdapter) = 0;
>
>          virtual HRESULT STDMETHODCALLTYPE MakeWindowAssociation(
>              HWND WindowHandle,
>              UINT Flags) = 0;
>
>          virtual HRESULT STDMETHODCALLTYPE GetWindowAssociation(
>              /* [annotation][out] */
>              _Out_  HWND *pWindowHandle) = 0;
>
>          virtual HRESULT STDMETHODCALLTYPE CreateSwapChain(
>              /* [annotation][in] */
>              _In_  IUnknown *pDevice,
>              /* [annotation][in] */
>              _In_  DXGI_SWAP_CHAIN_DESC *pDesc,
>              /* [annotation][out] */
>              _COM_Outptr_  IDXGISwapChain **ppSwapChain) = 0;
>
>          virtual HRESULT STDMETHODCALLTYPE CreateSoftwareAdapter(
>              /* [in] */ HMODULE Module,
>              /* [annotation][out] */
>              _COM_Outptr_  IDXGIAdapter **ppAdapter) = 0;
>
>      };
>
>
> #else /* C style interface */
>
>      typedef struct IDXGIFactoryVtbl
>      {
>          BEGIN_INTERFACE
>
>          HRESULT ( STDMETHODCALLTYPE *QueryInterface )(
>              IDXGIFactory * This,
>              /* [in] */ REFIID riid,
>              /* [annotation][iid_is][out] */
>              _COM_Outptr_  void **ppvObject);
>
>          ULONG ( STDMETHODCALLTYPE *AddRef )(
>              IDXGIFactory * This);
>
>          ULONG ( STDMETHODCALLTYPE *Release )(
>              IDXGIFactory * This);
>
>          HRESULT ( STDMETHODCALLTYPE *SetPrivateData )(
>              IDXGIFactory * This,
>              /* [annotation][in] */
>              _In_  REFGUID Name,
>              /* [in] */ UINT DataSize,
>              /* [annotation][in] */
>              _In_reads_bytes_(DataSize)  const void *pData);
>
>          HRESULT ( STDMETHODCALLTYPE *SetPrivateDataInterface )(
>              IDXGIFactory * This,
>              /* [annotation][in] */
>              _In_  REFGUID Name,
>              /* [annotation][in] */
>              _In_opt_  const IUnknown *pUnknown);
>
>          HRESULT ( STDMETHODCALLTYPE *GetPrivateData )(
>              IDXGIFactory * This,
>              /* [annotation][in] */
>              _In_  REFGUID Name,
>              /* [annotation][out][in] */
>              _Inout_  UINT *pDataSize,
>              /* [annotation][out] */
>              _Out_writes_bytes_(*pDataSize)  void *pData);
>
>          HRESULT ( STDMETHODCALLTYPE *GetParent )(
>              IDXGIFactory * This,
>              /* [annotation][in] */
>              _In_  REFIID riid,
>              /* [annotation][retval][out] */
>              _COM_Outptr_  void **ppParent);
>
>          HRESULT ( STDMETHODCALLTYPE *EnumAdapters )(
>              IDXGIFactory * This,
>              /* [in] */ UINT Adapter,
>              /* [annotation][out] */
>              _COM_Outptr_  IDXGIAdapter **ppAdapter);
>
>          HRESULT ( STDMETHODCALLTYPE *MakeWindowAssociation )(
>              IDXGIFactory * This,
>              HWND WindowHandle,
>              UINT Flags);
>
>          HRESULT ( STDMETHODCALLTYPE *GetWindowAssociation )(
>              IDXGIFactory * This,
>              /* [annotation][out] */
>              _Out_  HWND *pWindowHandle);
>
>          HRESULT ( STDMETHODCALLTYPE *CreateSwapChain )(
>              IDXGIFactory * This,
>              /* [annotation][in] */
>              _In_  IUnknown *pDevice,
>              /* [annotation][in] */
>              _In_  DXGI_SWAP_CHAIN_DESC *pDesc,
>              /* [annotation][out] */
>              _COM_Outptr_  IDXGISwapChain **ppSwapChain);
>
>          HRESULT ( STDMETHODCALLTYPE *CreateSoftwareAdapter )(
>              IDXGIFactory * This,
>              /* [in] */ HMODULE Module,
>              /* [annotation][out] */
>              _COM_Outptr_  IDXGIAdapter **ppAdapter);
>
>          END_INTERFACE
>      } IDXGIFactoryVtbl;
>
>      interface IDXGIFactory
>      {
>          CONST_VTBL struct IDXGIFactoryVtbl *lpVtbl;
>      };
>
>