util: Add EventEmitter
Change-Id: I08e8beea7a05abe30cc818ec2d44acffecf07343
diff --git a/src/util/event-emitter.hpp b/src/util/event-emitter.hpp
new file mode 100644
index 0000000..adbd231
--- /dev/null
+++ b/src/util/event-emitter.hpp
@@ -0,0 +1,381 @@
+/* -*- 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/>.
+ **/
+
+
+#ifndef NDN_UTIL_EVENT_EMITTER_HPP
+#define NDN_UTIL_EVENT_EMITTER_HPP
+
+#include "common.hpp"
+#include <vector>
+
+namespace ndn {
+namespace util {
+
+struct empty
+{
+};
+
+/** \class EventEmitter
+ * \brief provides a lightweight event system
+ *
+ * To declare an event:
+ * EventEmitter<TArgs> onEventName;
+ * To subscribe to an event:
+ * eventSource->onEventName += eventHandler;
+ * Multiple functions can subscribe to the same event.
+ * To trigger an event:
+ * onEventName(args);
+ * To clear event subscriptions:
+ * onEventName.clear();
+ */
+
+// four arguments
+template<typename T1 = empty, typename T2 = empty,
+ typename T3 = empty, typename T4 = empty>
+class EventEmitter : noncopyable
+{
+public:
+ /// represents a handler that can subscribe to the event
+ typedef function<void(const T1&, const T2&,
+ const T3&, const T4&)> Handler;
+
+ /// adds an subscription
+ void
+ operator+=(Handler handler);
+
+ /// returns true if there is no subscription,
+ /// otherwise returns false
+ bool
+ isEmpty() const;
+
+ /// clears all subscriptions
+ void
+ clear();
+
+ /// triggers the event
+ void
+ operator()(const T1& a1, const T2& a2, const T3& a3, const T4& a4);
+
+private:
+ /// stores all subscribed handlers
+ std::vector<Handler> m_handlers;
+};
+
+// zero argument
+template<>
+class EventEmitter<empty, empty, empty, empty> : noncopyable
+{
+public:
+ typedef function<void()> Handler;
+
+ void
+ operator+=(Handler handler);
+
+ bool
+ isEmpty() const;
+
+ void
+ clear();
+
+ void
+ operator()();
+
+private:
+ std::vector<Handler> m_handlers;
+};
+
+
+// one argument
+template<typename T1>
+class EventEmitter<T1, empty, empty, empty> : noncopyable
+{
+public:
+ typedef function<void(const T1&)> Handler;
+
+ void
+ operator+=(Handler handler);
+
+ bool
+ isEmpty() const;
+
+ void
+ clear();
+
+ void
+ operator()(const T1& a1);
+
+private:
+ std::vector<Handler> m_handlers;
+};
+
+
+// two arguments
+template<typename T1, typename T2>
+class EventEmitter<T1, T2, empty, empty> : noncopyable
+{
+public:
+ typedef function<void(const T1&, const T2&)> Handler;
+
+ void
+ operator+=(Handler handler);
+
+ bool
+ isEmpty() const;
+
+ void
+ clear();
+
+ void
+ operator()(const T1& a1, const T2& a2);
+
+private:
+ std::vector<Handler> m_handlers;
+};
+
+
+// three arguments
+template<typename T1, typename T2, typename T3>
+class EventEmitter<T1, T2, T3, empty> : noncopyable
+{
+public:
+ typedef function<void(const T1&, const T2&, const T3&)> Handler;
+
+ void
+ operator+=(Handler handler);
+
+ bool
+ isEmpty() const;
+
+ void
+ clear();
+
+ void
+ operator()(const T1& a1, const T2& a2, const T3& a3);
+
+private:
+ std::vector<Handler> m_handlers;
+};
+
+
+// zero argument
+
+inline void
+EventEmitter<empty, empty, empty, empty>::operator+=(Handler handler)
+{
+ m_handlers.push_back(handler);
+}
+
+inline bool
+EventEmitter<empty, empty, empty, empty>::isEmpty() const
+{
+ return m_handlers.empty();
+}
+
+inline void
+EventEmitter<empty, empty, empty, empty>::clear()
+{
+ return m_handlers.clear();
+}
+
+inline void
+EventEmitter<empty, empty, empty, empty>::operator()()
+{
+ std::vector<Handler>::iterator it;
+ for (it = m_handlers.begin(); it != m_handlers.end(); ++it) {
+ (*it)();
+ if (m_handlers.empty()) // .clear has been called
+ return;
+ }
+}
+
+// one argument
+
+template<typename T1>
+inline void
+EventEmitter<T1, empty, empty, empty>::operator+=(Handler handler)
+{
+ m_handlers.push_back(handler);
+}
+
+template<typename T1>
+inline bool
+EventEmitter<T1, empty, empty, empty>::isEmpty() const
+{
+ return m_handlers.empty();
+}
+
+template<typename T1>
+inline void
+EventEmitter<T1, empty, empty, empty>::clear()
+{
+ return m_handlers.clear();
+}
+
+template<typename T1>
+inline void
+EventEmitter<T1, empty, empty, empty>::operator()(const T1& a1)
+{
+ typename std::vector<Handler>::iterator it;
+ for (it = m_handlers.begin(); it != m_handlers.end(); ++it) {
+ (*it)(a1);
+ if (m_handlers.empty()) // .clear has been called
+ return;
+ }
+}
+
+// two arguments
+
+template<typename T1, typename T2>
+inline void
+EventEmitter<T1, T2, empty, empty>::operator+=(Handler handler)
+{
+ m_handlers.push_back(handler);
+}
+
+template<typename T1, typename T2>
+inline bool
+EventEmitter<T1, T2, empty, empty>::isEmpty() const
+{
+ return m_handlers.empty();
+}
+
+template<typename T1, typename T2>
+inline void
+EventEmitter<T1, T2, empty, empty>::clear()
+{
+ return m_handlers.clear();
+}
+
+template<typename T1, typename T2>
+inline void
+EventEmitter<T1, T2, empty, empty>::operator()
+ (const T1& a1, const T2& a2)
+{
+ typename std::vector<Handler>::iterator it;
+ for (it = m_handlers.begin(); it != m_handlers.end(); ++it) {
+ (*it)(a1, a2);
+ if (m_handlers.empty()) // .clear has been called
+ return;
+ }
+}
+
+// three arguments
+
+template<typename T1, typename T2, typename T3>
+inline void
+EventEmitter<T1, T2, T3, empty>::operator+=(Handler handler)
+{
+ m_handlers.push_back(handler);
+}
+
+template<typename T1, typename T2, typename T3>
+inline bool
+EventEmitter<T1, T2, T3, empty>::isEmpty() const
+{
+ return m_handlers.empty();
+}
+
+template<typename T1, typename T2, typename T3>
+inline void
+EventEmitter<T1, T2, T3, empty>::clear()
+{
+ return m_handlers.clear();
+}
+
+template<typename T1, typename T2, typename T3>
+inline void
+EventEmitter<T1, T2, T3, empty>::operator()
+ (const T1& a1, const T2& a2, const T3& a3)
+{
+ typename std::vector<Handler>::iterator it;
+ for (it = m_handlers.begin(); it != m_handlers.end(); ++it) {
+ (*it)(a1, a2, a3);
+ if (m_handlers.empty()) // .clear has been called
+ return;
+ }
+}
+
+// four arguments
+
+template<typename T1, typename T2, typename T3, typename T4>
+inline void
+EventEmitter<T1, T2, T3, T4>::operator+=(Handler handler)
+{
+ m_handlers.push_back(handler);
+}
+
+template<typename T1, typename T2, typename T3, typename T4>
+inline bool
+EventEmitter<T1, T2, T3, T4>::isEmpty() const
+{
+ return m_handlers.empty();
+}
+
+template<typename T1, typename T2, typename T3, typename T4>
+inline void
+EventEmitter<T1, T2, T3, T4>::clear()
+{
+ return m_handlers.clear();
+}
+
+template<typename T1, typename T2, typename T3, typename T4>
+inline void
+EventEmitter<T1, T2, T3, T4>::operator()
+ (const T1& a1, const T2& a2, const T3& a3, const T4& a4)
+{
+ typename std::vector<Handler>::iterator it;
+ for (it = m_handlers.begin(); it != m_handlers.end(); ++it) {
+ (*it)(a1, a2, a3, a4);
+ if (m_handlers.empty()) // .clear has been called
+ return;
+ }
+}
+
+
+} // namespace util
+} // namespace ndn
+
+#endif // NDN_UTIL_EVENT_EMITTER_HPP