Version 1.8 of gecko-sdk. Downloaded from here:...

gecko-sdk/include/nsIInterfaceRequestorUtils.h

+/* -*- Mode: IDL; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * ***** BEGIN LICENSE BLOCK *****
+ * Version: MPL 1.1/GPL 2.0/LGPL 2.1
+ *
+ * The contents of this file are subject to the Mozilla Public License Version
+ * 1.1 (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ * http://www.mozilla.org/MPL/
+ *
+ * Software distributed under the License is distributed on an "AS IS" basis,
+ * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
+ * for the specific language governing rights and limitations under the
+ * License.
+ *
+ * The Original Code is the Mozilla browser.
+ *
+ * The Initial Developer of the Original Code is
+ * Netscape Communications, Inc.
+ * Portions created by the Initial Developer are Copyright (C) 1999
+ * the Initial Developer. All Rights Reserved.
+ *
+ * Contributor(s):
+ *
+ * Alternatively, the contents of this file may be used under the terms of
+ * either of the GNU General Public License Version 2 or later (the "GPL"),
+ * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
+ * in which case the provisions of the GPL or the LGPL are applicable instead
+ * of those above. If you wish to allow use of your version of this file only
+ * under the terms of either the GPL or the LGPL, and not to allow others to
+ * use your version of this file under the terms of the MPL, indicate your
+ * decision by deleting the provisions above and replace them with the notice
+ * and other provisions required by the GPL or the LGPL. If you do not delete
+ * the provisions above, a recipient may use your version of this file under
+ * the terms of any one of the MPL, the GPL or the LGPL.
+ *
+ * ***** END LICENSE BLOCK ***** */
+
+#ifndef __nsInterfaceRequestorUtils_h
+#define __nsInterfaceRequestorUtils_h
+
+#include "nsCOMPtr.h"
+
+// a type-safe shortcut for calling the |GetInterface()| member function
+// T must inherit from nsIInterfaceRequestor, but the cast may be ambiguous.
+template <class T, class DestinationType>
+inline
+nsresult
+CallGetInterface( T* aSource, DestinationType** aDestination )
+  {
+    NS_PRECONDITION(aSource, "null parameter");
+    NS_PRECONDITION(aDestination, "null parameter");
+
+    return aSource->GetInterface(NS_GET_IID(DestinationType),
+                                 NS_REINTERPRET_CAST(void**, aDestination));
+  }
+
+class NS_COM_GLUE nsGetInterface : public nsCOMPtr_helper
+  {
+    public:
+      nsGetInterface( nsISupports* aSource, nsresult* error )
+          : mSource(aSource),
+            mErrorPtr(error)
+        {
+          // nothing else to do here
+        }
+
+      virtual nsresult NS_FASTCALL operator()( const nsIID&, void** ) const;
+
+    private:
+      nsISupports*          mSource;
+      nsresult*             mErrorPtr;
+  };
+
+inline
+const nsGetInterface
+do_GetInterface( nsISupports* aSource, nsresult* error = 0 )
+  {
+    return nsGetInterface(aSource, error);
+  }
+
+#endif // __nsInterfaceRequestorUtils_h
+