util: Add EventEmitter

Change-Id: I08e8beea7a05abe30cc818ec2d44acffecf07343
diff --git a/tests/unit-tests/util/test-event-emitter.cpp b/tests/unit-tests/util/test-event-emitter.cpp
new file mode 100644
index 0000000..8dd5314
--- /dev/null
+++ b/tests/unit-tests/util/test-event-emitter.cpp
@@ -0,0 +1,275 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/**
+ * Copyright (c) 2013-2014 Regents of the University of California.
+ *
+ * This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
+ *
+ * ndn-cxx 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 3 of the License, or (at your option) any later version.
+ *
+ * ndn-cxx 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 copies of the GNU General Public License and GNU Lesser
+ * General Public License along with ndn-cxx, e.g., in COPYING.md file.  If not, see
+ * <http://www.gnu.org/licenses/>.
+ *
+ * See AUTHORS.md for complete list of ndn-cxx authors and contributors.
+ *
+ * This code is actually copied from NFD project (NDN Forwarding Daemon).
+ * We acknowledge the permission of the authors of NFD.
+ */
+/**
+ * Copyright (c) 2014  Regents of the University of California,
+ *                     Arizona Board of Regents,
+ *                     Colorado State University,
+ *                     University Pierre & Marie Curie, Sorbonne University,
+ *                     Washington University in St. Louis,
+ *                     Beijing Institute of Technology
+ *
+ * This file is part of NFD (Named Data Networking Forwarding Daemon).
+ * See AUTHORS.md for complete list of NFD authors and contributors.
+ *
+ * NFD is free software: you can redistribute it and/or modify it under the terms
+ * of the GNU General Public License as published by the Free Software Foundation,
+ * either version 3 of the License, or (at your option) any later version.
+ *
+ * NFD 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * NFD, e.g., in COPYING.md file.  If not, see <http://www.gnu.org/licenses/>.
+ **/
+
+#include "util/event-emitter.hpp"
+
+#include "boost-test.hpp"
+
+namespace ndn {
+namespace tests {
+
+using ndn::util::EventEmitter;
+
+BOOST_AUTO_TEST_SUITE(UtilEventEmitter)
+
+class EventEmitterTester : noncopyable
+{
+public:
+  EventEmitterTester();
+
+  int m_hit;
+  int m_a1;
+  int m_a2;
+  int m_a3;
+  int m_a4;
+
+  void
+  clear();
+
+  void
+  f0();
+
+  void
+  f1(int a1);
+
+  void
+  f2(int a1, int a2);
+
+  void
+  f3(int a1, int a2, int a3);
+
+  void
+  f4(int a1, int a2, int a3, int a4);
+};
+
+EventEmitterTester::EventEmitterTester()
+{
+  this->clear();
+}
+
+void
+EventEmitterTester::clear()
+{
+  m_hit = 0;
+  m_a1 = 0;
+  m_a2 = 0;
+  m_a3 = 0;
+  m_a4 = 0;
+}
+
+void
+EventEmitterTester::f0()
+{
+  ++m_hit;
+}
+
+void
+EventEmitterTester::f1(int a1)
+{
+  ++m_hit;
+  m_a1 = a1;
+}
+
+void
+EventEmitterTester::f2(int a1, int a2)
+{
+  ++m_hit;
+  m_a1 = a1;
+  m_a2 = a2;
+}
+
+void
+EventEmitterTester::f3(int a1, int a2, int a3)
+{
+  ++m_hit;
+  m_a1 = a1;
+  m_a2 = a2;
+  m_a3 = a3;
+}
+
+void
+EventEmitterTester::f4(int a1, int a2, int a3, int a4)
+{
+  ++m_hit;
+  m_a1 = a1;
+  m_a2 = a2;
+  m_a3 = a3;
+  m_a4 = a4;
+}
+
+static int g_EventEmitterTest_RefObject_copyCount;
+
+class EventEmitterTest_RefObject
+{
+public:
+  EventEmitterTest_RefObject() {}
+
+  EventEmitterTest_RefObject(const EventEmitterTest_RefObject& other);
+};
+
+EventEmitterTest_RefObject::EventEmitterTest_RefObject(const EventEmitterTest_RefObject& other)
+{
+  ++g_EventEmitterTest_RefObject_copyCount;
+}
+
+void
+EventEmitterTest_RefObject_byVal(EventEmitterTest_RefObject a1) {}
+
+void
+EventEmitterTest_RefObject_byRef(const EventEmitterTest_RefObject& a1) {}
+
+
+BOOST_AUTO_TEST_CASE(ZeroListener)
+{
+  EventEmitter<> ee;
+  BOOST_CHECK_NO_THROW(ee());
+}
+
+BOOST_AUTO_TEST_CASE(TwoListeners)
+{
+  EventEmitterTester eet1;
+  EventEmitterTester eet2;
+  EventEmitter<> ee;
+  ee += bind(&EventEmitterTester::f0, &eet1);
+  ee += bind(&EventEmitterTester::f0, &eet2);
+  ee();
+
+  BOOST_CHECK_EQUAL(eet1.m_hit, 1);
+  BOOST_CHECK_EQUAL(eet2.m_hit, 1);
+}
+
+BOOST_AUTO_TEST_CASE(ZeroArgument)
+{
+  EventEmitterTester eet;
+  EventEmitter<> ee;
+  ee += bind(&EventEmitterTester::f0, &eet);
+  ee();
+
+  BOOST_CHECK_EQUAL(eet.m_hit, 1);
+}
+
+BOOST_AUTO_TEST_CASE(OneArgument)
+{
+  EventEmitterTester eet;
+  EventEmitter<int> ee;
+  ee += bind(&EventEmitterTester::f1, &eet, _1);
+  ee(11);
+
+  BOOST_CHECK_EQUAL(eet.m_hit, 1);
+  BOOST_CHECK_EQUAL(eet.m_a1, 11);
+}
+
+BOOST_AUTO_TEST_CASE(TwoArguments)
+{
+  EventEmitterTester eet;
+  EventEmitter<int,int> ee;
+  ee += bind(&EventEmitterTester::f2, &eet, _1, _2);
+  ee(21, 22);
+
+  BOOST_CHECK_EQUAL(eet.m_hit, 1);
+  BOOST_CHECK_EQUAL(eet.m_a1, 21);
+  BOOST_CHECK_EQUAL(eet.m_a2, 22);
+}
+
+BOOST_AUTO_TEST_CASE(ThreeArguments)
+{
+  EventEmitterTester eet;
+  EventEmitter<int,int,int> ee;
+  ee += bind(&EventEmitterTester::f3, &eet, _1, _2, _3);
+  ee(31, 32, 33);
+
+  BOOST_CHECK_EQUAL(eet.m_hit, 1);
+  BOOST_CHECK_EQUAL(eet.m_a1, 31);
+  BOOST_CHECK_EQUAL(eet.m_a2, 32);
+  BOOST_CHECK_EQUAL(eet.m_a3, 33);
+}
+
+BOOST_AUTO_TEST_CASE(FourArguments)
+{
+  EventEmitterTester eet;
+  EventEmitter<int,int,int,int> ee;
+  ee += bind(&EventEmitterTester::f4, &eet, _1, _2, _3, _4);
+  ee(41, 42, 43, 44);
+
+  BOOST_CHECK_EQUAL(eet.m_hit, 1);
+  BOOST_CHECK_EQUAL(eet.m_a1, 41);
+  BOOST_CHECK_EQUAL(eet.m_a2, 42);
+  BOOST_CHECK_EQUAL(eet.m_a3, 43);
+  BOOST_CHECK_EQUAL(eet.m_a4, 44);
+}
+
+// EventEmitter passes arguments by reference,
+// but it also allows a handler that accept arguments by value
+BOOST_AUTO_TEST_CASE(HandlerByVal)
+{
+  EventEmitterTest_RefObject refObject;
+  g_EventEmitterTest_RefObject_copyCount = 0;
+
+  EventEmitter<EventEmitterTest_RefObject> ee;
+  ee += &EventEmitterTest_RefObject_byVal;
+  ee(refObject);
+
+  BOOST_CHECK_EQUAL(g_EventEmitterTest_RefObject_copyCount, 1);
+}
+
+// EventEmitter passes arguments by reference, and no copying
+// is necessary when handler accepts arguments by reference
+BOOST_AUTO_TEST_CASE(HandlerByRef)
+{
+  EventEmitterTest_RefObject refObject;
+  g_EventEmitterTest_RefObject_copyCount = 0;
+
+  EventEmitter<EventEmitterTest_RefObject> ee;
+  ee += &EventEmitterTest_RefObject_byRef;
+  ee(refObject);
+
+  BOOST_CHECK_EQUAL(g_EventEmitterTest_RefObject_copyCount, 0);
+}
+
+BOOST_AUTO_TEST_SUITE_END()
+
+} // namespace tests
+} // namespace ndn