dmusic: Simplify and cleanup IDirectMusicInstrument constructor.

dlls/dmusic/collection.c

@@ -377,7 +377,7 @@ static HRESULT WINAPI collection_stream_Load(IPersistStream *iface,
                                             DMUS_PRIVATE_INSTRUMENTENTRY *new_instrument = calloc(1, sizeof(DMUS_PRIVATE_INSTRUMENTENTRY));
                                             TRACE_(dmfile)(": instrument list\n");
                                             /* Only way to create this one... even M$ does it discretely */
-                                            DMUSIC_CreateDirectMusicInstrumentImpl(&IID_IDirectMusicInstrument, (void**)&new_instrument->pInstrument, NULL);
+                                            instrument_create(&new_instrument->pInstrument);
                                             {
                                                 IDirectMusicInstrumentImpl *instrument = impl_from_IDirectMusicInstrument(new_instrument->pInstrument);
                                                 /* Store offset and length, they will be needed when loading the instrument */

dlls/dmusic/dmusic_private.h

@@ -97,10 +97,11 @@ extern HRESULT collection_create(IUnknown **ret_iface);
 /* Internal */
 extern HRESULT DMUSIC_CreateDirectMusicBufferImpl(LPDMUS_BUFFERDESC desc, LPVOID* ret_iface);
 extern HRESULT DMUSIC_CreateReferenceClockImpl (LPCGUID lpcGUID, LPVOID* ppobj, LPUNKNOWN pUnkOuter);
-extern HRESULT DMUSIC_CreateDirectMusicInstrumentImpl (LPCGUID lpcGUID, LPVOID* ppobj, LPUNKNOWN pUnkOuter);
 
 extern HRESULT download_create(DWORD size, IDirectMusicDownload **ret_iface);
 
+extern HRESULT instrument_create(IDirectMusicInstrument **ret_iface);
+
 /*****************************************************************************
  * IDirectMusic8Impl implementation structure
  */

dlls/dmusic/instrument.c

@@ -119,24 +119,18 @@ static const IDirectMusicInstrumentVtbl DirectMusicInstrument_Vtbl =
     IDirectMusicInstrumentImpl_SetPatch
 };
 
-/* for ClassFactory */
-HRESULT DMUSIC_CreateDirectMusicInstrumentImpl (LPCGUID lpcGUID, LPVOID* ppobj, LPUNKNOWN pUnkOuter) {
-	IDirectMusicInstrumentImpl* dminst;
-        HRESULT hr;
+HRESULT instrument_create(IDirectMusicInstrument **ret_iface)
+{
+    IDirectMusicInstrumentImpl *dminst;
 
-	dminst = calloc(1, sizeof(IDirectMusicInstrumentImpl));
-	if (NULL == dminst) {
-		*ppobj = NULL;
-		return E_OUTOFMEMORY;
-	}
+    *ret_iface = NULL;
+    if (!(dminst = calloc(1, sizeof(*dminst)))) return E_OUTOFMEMORY;
     dminst->IDirectMusicInstrument_iface.lpVtbl = &DirectMusicInstrument_Vtbl;
     dminst->ref = 1;
 
-        hr = IDirectMusicInstrument_QueryInterface(&dminst->IDirectMusicInstrument_iface, lpcGUID,
-                ppobj);
-        IDirectMusicInstrument_Release(&dminst->IDirectMusicInstrument_iface);
-
-        return hr;
+    TRACE("Created DirectMusicInstrument %p\n", dminst);
+    *ret_iface = &dminst->IDirectMusicInstrument_iface;
+    return S_OK;
 }
 
 static HRESULT read_from_stream(IStream *stream, void *data, ULONG size)