DDRAW: Fix reference counting

[Stefan Dösinger]

Hello,

> In that case, it would be really beneficial with a unit test.
> Both as documentation and to see what Windows does.
Excuse my ignorance, but what exactly is meant with 'unit test'? As far as 
I've learned, it's a small piece of code which uses this functionality and 
checks the results. My patch includes such a test:

--- /dev/null	2005-09-01 15:22:32.000000000 +0200
+++ dlls/ddraw/tests/refcount.c	2005-09-18 21:57:52.000000000 +0200
<...>
+    /* Create a Texture. Increases the refcount by 2!!!*/
+    memset(&ddsd, 0, sizeof(ddsd));
+    ddsd.dwSize = sizeof(ddsd);
+    ddsd.dwFlags = DDSD_CAPS | DDSD_HEIGHT | DDSD_WIDTH | DDSD_PIXELFORMAT;
+    ddsd.ddsCaps.dwCaps = DDSCAPS_TEXTURE;
<...>
+    rc = IDirectDraw7_CreateSurface( lpDD, &ddsd, &lpDDS, NULL );
+    ok(rc == DD_OK, "CreateSurface for a mipmap surface returned %lx\n", rc);
+    if(rc == DD_OK)
+    {
+        newref = IDirectDraw_AddRef(lpDD) - 1;
+        IDirectDraw_Release(lpDD);
+        ok( (newref - oldref) == 2, "DD reference count increased by %d 
during creation of a mipmap surface\n", newref - oldref);
+        oldref = newref;
+
+        newref = IDirectDrawSurface_AddRef(lpDDS) - 1;
+        IDirectDrawSurface_Release(lpDDS);
+        ok(newref == 1, "Initial surface reference count of a mipmap surface 
is %d\n", newref);
+    
+        /* Release the surface */
+        IDirectDrawSurface_Release(lpDDS);
+
+        newref = IDirectDraw_AddRef(lpDD) - 1;
+        IDirectDraw_Release(lpDD);
+        ok( (newref - oldref) == -2, "DD reference count decreased by %d 
during releasing a mipmap surface\n", newref - oldref);
+    }

Is that enought? This test succeeds in Windows 2000 and Windows 95.

Stefan