utils: adding Utils::Function to support polymorphic function wrappers

Utils::Function wraps std::function or std::tr1::function to give
polymorphic function wrappers, i.e. a way to accept function pointers
or functors as arguments as long as they have the correct signature.

Change-Id: I4032264cf6b84ef647f790c566543633b4d0653b
Reviewed-by: hjk <hjk121@nokiamail.com>

src/libs/utils/function.cpp

@@ -0,0 +1,69 @@
+/****************************************************************************
+**
+** Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies).
+** Contact: http://www.qt-project.org/legal
+**
+** This file is part of Qt Creator.
+**
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and Digia.  For licensing terms and
+** conditions see http://qt.digia.com/licensing.  For further information
+** use the contact form at http://qt.digia.com/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU Lesser General Public License version 2.1 requirements
+** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Digia gives you certain additional
+** rights.  These rights are described in the Digia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+****************************************************************************/
+
+#include "function.h"
+
+namespace {
+// just compilation tests
+
+void test();
+
+void functionUser(Utils::function<int()> generator, Utils::function<void(int)> consumer)
+{
+    consumer(generator());
+}
+
+struct GenFunctor
+{
+    int operator()() { return 29; }
+};
+
+struct ConsumerFunctor
+{
+    void operator()(int) {}
+};
+
+int generatorF()
+{
+    return 42;
+}
+
+void consumerF(int i)
+{
+    if (i < 0)
+        test();
+}
+
+void test()
+{
+    functionUser(GenFunctor(), ConsumerFunctor());
+    functionUser(&generatorF, &consumerF);
+}
+
+} // end namespace