comdlg32/itemdlg: Fix setting NULL file name (Coverity).

dlls/comdlg32/itemdlg.c

@@ -384,14 +384,12 @@ static UINT get_file_name(FileDialogImpl *This, LPWSTR *str)
 
 static BOOL set_file_name(FileDialogImpl *This, LPCWSTR str)
 {
-    HWND hwnd_edit = GetDlgItem(This->dlg_hwnd, IDC_FILENAME);
-
     if(This->set_filename)
         LocalFree(This->set_filename);
 
-    This->set_filename = StrDupW(str);
+    This->set_filename = str ? StrDupW(str) : NULL;
 
-    return SendMessageW(hwnd_edit, WM_SETTEXT, 0, (LPARAM)str);
+    return SetDlgItemTextW(This->dlg_hwnd, IDC_FILENAME, This->set_filename);
 }
 
 static void fill_filename_from_selection(FileDialogImpl *This)
@@ -2608,10 +2606,8 @@ static HRESULT WINAPI IFileDialog2_fnGetFileName(IFileDialog2 *iface, LPWSTR *ps
         return E_INVALIDARG;
 
     *pszName = NULL;
-    if(get_file_name(This, pszName))
-        return S_OK;
-    else
-        return E_FAIL;
+    get_file_name(This, pszName);
+    return *pszName ? S_OK : E_FAIL;
 }
 
 static HRESULT WINAPI IFileDialog2_fnSetTitle(IFileDialog2 *iface, LPCWSTR pszTitle)

dlls/comdlg32/tests/itemdlg.c

@@ -797,6 +797,21 @@ static void test_basics(void)
     ok(hr == S_OK, "got 0x%08x\n", hr);
     hr = IFileOpenDialog_SetFileName(pfod, null);
     ok(hr == S_OK, "got 0x%08x\n", hr);
+
+    filename = NULL;
+    hr = IFileOpenDialog_GetFileName(pfod, &filename);
+    ok(hr == S_OK, "Got 0x%08x\n", hr);
+    ok(!lstrcmpW(filename, null), "Strings do not match.\n");
+    CoTaskMemFree(filename);
+
+    hr = IFileOpenDialog_SetFileName(pfod, NULL);
+    ok(hr == S_OK, "got 0x%08x\n", hr);
+
+    filename = (void*)0xdeadbeef;
+    hr = IFileOpenDialog_GetFileName(pfod, &filename);
+    ok(hr == E_FAIL, "Got 0x%08x\n", hr);
+    ok(filename == NULL, "got %p.\n", filename);
+
     hr = IFileOpenDialog_SetFileName(pfod, txt);
     ok(hr == S_OK, "got 0x%08x\n", hr);
     hr = IFileOpenDialog_GetFileName(pfod, &filename);