dmloader: Fix a possible null dereference.

configure

@@ -14505,6 +14505,14 @@ dlls/dmloader/Makefile: dlls/dmloader/Makefile.in dlls/Makedll.rules"
 ac_config_files="$ac_config_files dlls/dmloader/Makefile"
 
 ALL_MAKEFILES="$ALL_MAKEFILES \\
+	dlls/dmloader/tests/Makefile"
+test "x$enable_tests" != xno && ALL_TEST_DIRS="$ALL_TEST_DIRS \\
+	dmloader/tests"
+ALL_MAKEFILE_DEPENDS="$ALL_MAKEFILE_DEPENDS
+dlls/dmloader/tests/Makefile: dlls/dmloader/tests/Makefile.in dlls/Maketest.rules"
+ac_config_files="$ac_config_files dlls/dmloader/tests/Makefile"
+
+ALL_MAKEFILES="$ALL_MAKEFILES \\
 	dlls/dmscript/Makefile"
 test "x$enable_dmscript" != xno && ALL_DLL_DIRS="$ALL_DLL_DIRS \\
 	dmscript"
@@ -18839,6 +18847,7 @@ do
     "dlls/dmcompos/Makefile") CONFIG_FILES="$CONFIG_FILES dlls/dmcompos/Makefile" ;;
     "dlls/dmime/Makefile") CONFIG_FILES="$CONFIG_FILES dlls/dmime/Makefile" ;;
     "dlls/dmloader/Makefile") CONFIG_FILES="$CONFIG_FILES dlls/dmloader/Makefile" ;;
+    "dlls/dmloader/tests/Makefile") CONFIG_FILES="$CONFIG_FILES dlls/dmloader/tests/Makefile" ;;
     "dlls/dmscript/Makefile") CONFIG_FILES="$CONFIG_FILES dlls/dmscript/Makefile" ;;
     "dlls/dmstyle/Makefile") CONFIG_FILES="$CONFIG_FILES dlls/dmstyle/Makefile" ;;
     "dlls/dmsynth/Makefile") CONFIG_FILES="$CONFIG_FILES dlls/dmsynth/Makefile" ;;

configure.ac

@@ -2224,6 +2224,7 @@ WINE_CONFIG_MAKEFILE([dlls/dmband/Makefile],[dlls/Makedll.rules],[dlls],[ALL_DLL
 WINE_CONFIG_MAKEFILE([dlls/dmcompos/Makefile],[dlls/Makedll.rules],[dlls],[ALL_DLL_DIRS])
 WINE_CONFIG_MAKEFILE([dlls/dmime/Makefile],[dlls/Makedll.rules],[dlls],[ALL_DLL_DIRS])
 WINE_CONFIG_MAKEFILE([dlls/dmloader/Makefile],[dlls/Makedll.rules],[dlls],[ALL_DLL_DIRS])
+WINE_CONFIG_MAKEFILE([dlls/dmloader/tests/Makefile],[dlls/Maketest.rules],[dlls],[ALL_TEST_DIRS],[enable_tests])
 WINE_CONFIG_MAKEFILE([dlls/dmscript/Makefile],[dlls/Makedll.rules],[dlls],[ALL_DLL_DIRS])
 WINE_CONFIG_MAKEFILE([dlls/dmstyle/Makefile],[dlls/Makedll.rules],[dlls],[ALL_DLL_DIRS])
 WINE_CONFIG_MAKEFILE([dlls/dmsynth/Makefile],[dlls/Makedll.rules],[dlls],[ALL_DLL_DIRS])

dlls/dmloader/loader.c

@@ -644,6 +644,8 @@ static HRESULT WINAPI IDirectMusicLoaderImpl_IDirectMusicLoader_ReleaseObject (L
 	ICOM_THIS_MULTI(IDirectMusicLoaderImpl, LoaderVtbl, iface);
 	TRACE("(%p, %p)\n", This, pObject);
 	
+	if(!pObject) return E_POINTER;
+
 	/* get descriptor */
 	DM_STRUCT_INIT(&Desc);
 	IDirectMusicObject_GetDescriptor (pObject, &Desc);

dlls/dmloader/tests/Makefile.in

+TOPSRCDIR = @top_srcdir@
+TOPOBJDIR = ../../..
+SRCDIR    = @srcdir@
+VPATH     = @srcdir@
+TESTDLL   = dmloader.dll
+IMPORTS   = ole32 kernel32
+
+CTESTS = \
+	loader.c
+
+@MAKE_TEST_RULES@
+
+@DEPENDENCIES@  # everything below this line is overwritten by make depend

dlls/dmloader/tests/loader.c

+/*
+ * Copyright (C) 2010 David Adam
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
+ */
+
+#include <assert.h>
+
+#define COBJMACROS
+
+#include "initguid.h"
+#include "dmusici.h"
+#include "wine/test.h"
+
+static void test_release_object(void)
+{
+    HRESULT hr;
+    IDirectMusicLoader8* loader = NULL;
+
+    hr = CoInitialize(NULL);
+    if ( FAILED(hr) )
+    {
+        skip("CoInitialize failed.\n");
+        return;
+    }
+
+    hr = CoCreateInstance(&CLSID_DirectMusicLoader, NULL, CLSCTX_INPROC, &IID_IDirectMusicLoader8, (void**)&loader);
+    if ( FAILED(hr) )
+    {
+        skip("CoCreateInstance failed.\n");
+        CoUninitialize();
+        return;
+    }
+
+    hr = IDirectMusicLoader_ReleaseObject(loader, NULL);
+    ok(hr == E_POINTER, "Expected E_POINTER, received %#x\n", hr);
+
+    IDirectMusicLoader_Release(loader);
+    CoUninitialize();
+}
+
+START_TEST(loader)
+{
+    test_release_object();
+}