shell32: Avoid pointer casts when background menu is created.

dlls/shell32/shell32_main.h

@@ -79,7 +79,7 @@ LPENUMFORMATETC	IEnumFORMATETC_Constructor(UINT, const FORMATETC []) DECLSPEC_HI
 
 LPCLASSFACTORY	IClassFactory_Constructor(REFCLSID) DECLSPEC_HIDDEN;
 IContextMenu2 *	ItemMenu_Constructor(IShellFolder*, LPCITEMIDLIST, const LPCITEMIDLIST*, UINT) DECLSPEC_HIDDEN;
-IContextMenu2 *	BackgroundMenu_Constructor(IShellFolder*, BOOL) DECLSPEC_HIDDEN;
+HRESULT BackgroundMenu_Constructor(IShellFolder*, BOOL, REFIID, void**) DECLSPEC_HIDDEN;
 LPSHELLVIEW	IShellView_Constructor(LPSHELLFOLDER) DECLSPEC_HIDDEN;
 
 HRESULT WINAPI IFSFolder_Constructor(IUnknown * pUnkOuter, REFIID riid, LPVOID * ppv) DECLSPEC_HIDDEN;

dlls/shell32/shfldr_desktop.c

@@ -530,10 +530,12 @@ static HRESULT WINAPI ISF_Desktop_fnGetUIObjectOf (IShellFolder2 * iface,
     if (IsEqualIID (riid, &IID_IContextMenu))
     {
         if (cidl > 0)
+        {
             pObj = (LPUNKNOWN) ItemMenu_Constructor( (IShellFolder *) iface, This->pidlRoot, apidl, cidl);
+            hr = S_OK;
+        }
         else
-            pObj = (LPUNKNOWN) BackgroundMenu_Constructor( (IShellFolder *) iface, TRUE);
-        hr = S_OK;
+            return BackgroundMenu_Constructor((IShellFolder*)iface, TRUE, riid, ppvOut);
     }
     else if (IsEqualIID (riid, &IID_IDataObject) && (cidl >= 1))
     {

dlls/shell32/shlview.c

@@ -1018,7 +1018,6 @@ static void ShellView_DoContextMenu(IShellViewImpl * This, WORD x, WORD y, BOOL
 	BOOL	fExplore = FALSE;
 	HWND	hwndTree = 0;
 	LPCONTEXTMENU	pContextMenu = NULL;
-	IContextMenu2 *pCM = NULL;
 	CMINVOKECOMMANDINFO	cmi;
 
 	TRACE("(%p)->(0x%08x 0x%08x 0x%08x) stub\n",This, x, y, bDefault);
@@ -1093,9 +1092,11 @@ static void ShellView_DoContextMenu(IShellViewImpl * This, WORD x, WORD y, BOOL
 	}
 	else	/* background context menu */
 	{
+	  IContextMenu2 *pCM;
+
 	  hMenu = CreatePopupMenu();
 
-	  pCM = BackgroundMenu_Constructor(This->pSFParent, FALSE);
+	  BackgroundMenu_Constructor(This->pSFParent, FALSE, &IID_IContextMenu2, (void**)&pCM);
 	  IContextMenu2_QueryContextMenu(pCM, hMenu, 0, FCIDM_SHVIEWFIRST, FCIDM_SHVIEWLAST, 0);
 
 	  uCommand = TrackPopupMenu( hMenu, TPM_LEFTALIGN | TPM_RETURNCMD,x,y,0,This->hWnd,NULL);
@@ -2049,10 +2050,7 @@ static HRESULT WINAPI IShellView_fnGetItemObject(IShellView2 *iface, UINT uItem,
     case SVGIO_BACKGROUND:
 
         if (IsEqualIID(&IID_IContextMenu, riid))
-        {
-            *ppvOut = BackgroundMenu_Constructor(This->pSFParent, FALSE);
-            hr = S_OK;
-        }
+            return BackgroundMenu_Constructor(This->pSFParent, FALSE, riid, ppvOut);
         else
             FIXME("unsupported interface requested %s\n", debugstr_guid(riid));
 

dlls/shell32/shlview_cmenu.c

@@ -877,11 +877,14 @@ static const IContextMenu3Vtbl BackgroundContextMenuVtbl =
     ContextMenu_HandleMenuMsg2
 };
 
-IContextMenu2 *BackgroundMenu_Constructor(IShellFolder *parent, BOOL desktop)
+HRESULT BackgroundMenu_Constructor(IShellFolder *parent, BOOL desktop, REFIID riid, void **pObj)
 {
     ContextMenu *This;
+    HRESULT hr;
 
     This = HeapAlloc(GetProcessHeap(), 0, sizeof(*This));
+    if (!This) return E_OUTOFMEMORY;
+
     This->IContextMenu3_iface.lpVtbl = &BackgroundContextMenuVtbl;
     This->ref = 1;
     This->parent = parent;
@@ -895,6 +898,8 @@ IContextMenu2 *BackgroundMenu_Constructor(IShellFolder *parent, BOOL desktop)
     This->desktop = desktop;
     if (parent) IShellFolder_AddRef(parent);
 
-    TRACE("(%p)\n", This);
-    return (IContextMenu2*)&This->IContextMenu3_iface;
+    hr = IContextMenu3_QueryInterface(&This->IContextMenu3_iface, riid, pObj);
+    IContextMenu3_Release(&This->IContextMenu3_iface);
+
+    return hr;
 }