util: EventEmitter
refs #1118
Change-Id: Ib2c080f7ad0f70f2fcd9cc738b8d3601dcc2a98c
diff --git a/daemon/util/event-emitter.hpp b/daemon/util/event-emitter.hpp
new file mode 100644
index 0000000..fa7de00
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+++ b/daemon/util/event-emitter.hpp
@@ -0,0 +1,325 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/**
+ * Copyright (C) 2014 Named Data Networking Project
+ * See COPYING for copyright and distribution information.
+ */
+
+#ifndef NFD_UTIL_EVENT_EMITTER_H
+#define NFD_UTIL_EVENT_EMITTER_H
+#include <vector>
+#include <boost/utility.hpp>
+#include <boost/function.hpp>
+namespace ndn {
+
+struct empty {};
+
+/** \class EventEmitter
+ * \brief provides a lightweight event system
+ *
+ * To declare an event:
+ * EventEmitter<TArgs> m_eventName;
+ * To subscribe to an event:
+ * eventSource->m_eventName += eventHandler;
+ * Multiple functions can subscribe to the same event.
+ * To trigger an event:
+ * m_eventName(args);
+ * To clear event subscriptions:
+ * m_eventName.clear();
+ */
+
+// four arguments
+template<typename T1 = empty, typename T2 = empty,
+ typename T3 = empty, typename T4 = empty>
+class EventEmitter : boost::noncopyable
+{
+public:
+ /// represents a handler that can subscribe to the event
+ typedef boost::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();
+
+ /// 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> : boost::noncopyable
+{
+public:
+ typedef boost::function<void()> Handler;
+
+ void
+ operator+=(Handler handler);
+
+ bool
+ isEmpty();
+
+ void
+ clear();
+
+ void
+ operator()();
+
+private:
+ std::vector<Handler> m_handlers;
+};
+
+
+// one argument
+template<typename T1>
+class EventEmitter<T1, empty, empty, empty> : boost::noncopyable
+{
+public:
+ typedef boost::function<void(const T1&)> Handler;
+
+ void
+ operator+=(Handler handler);
+
+ bool
+ isEmpty();
+
+ 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> : boost::noncopyable
+{
+public:
+ typedef boost::function<void(const T1&, const T2&)> Handler;
+
+ void
+ operator+=(Handler handler);
+
+ bool
+ isEmpty();
+
+ 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> : boost::noncopyable
+{
+public:
+ typedef boost::function<void(const T1&, const T2&,
+ const T3&)> Handler;
+
+ void
+ operator+=(Handler handler);
+
+ bool
+ isEmpty();
+
+ 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()
+{
+ 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)();
+ }
+}
+
+// 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()
+{
+ 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);
+ }
+}
+
+// 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()
+{
+ 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);
+ }
+}
+
+// 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()
+{
+ 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);
+ }
+}
+
+// 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()
+{
+ 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);
+ }
+}
+
+
+};//namespace ndn
+#endif//NFD_UTIL_EVENT_EMITTER_H