util: move signal-*.* into util/signal/ directory
refs #3940
Change-Id: I36e3420846959f39bb51a3ce7ef7f03e7c2c22aa
diff --git a/src/util/signal/connection.hpp b/src/util/signal/connection.hpp
new file mode 100644
index 0000000..6ee8e1c
--- /dev/null
+++ b/src/util/signal/connection.hpp
@@ -0,0 +1,89 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/*
+ * Copyright (c) 2013-2017 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.
+ */
+
+#ifndef NDN_UTIL_SIGNAL_CONNECTION_HPP
+#define NDN_UTIL_SIGNAL_CONNECTION_HPP
+
+#include "../../common.hpp"
+
+namespace ndn {
+namespace util {
+namespace signal {
+
+/** \brief represents a connection to a signal
+ * \note This type is copyable. Any copy can be used to disconnect.
+ */
+class Connection
+{
+public:
+ Connection();
+
+ /** \brief disconnects from the signal
+ * \note If the connection is already disconnected, or if the Signal has been destructed,
+ * this operation has no effect.
+ * \warning During signal emission, attempting to disconnect a connection other than
+ * the executing handler's own connection results in undefined behavior.
+ */
+ void
+ disconnect();
+
+ /** \brief check if connected to the signal
+ * \return false if disconnected from the signal
+ */
+ bool
+ isConnected() const;
+
+ /** \brief compare for equality
+ *
+ * Two connections are equal if they both refer to the same connection that isn't disconnected,
+ * or they are both disconnected.
+ */
+ bool
+ operator==(const Connection& other) const;
+
+ bool
+ operator!=(const Connection& other) const;
+
+private:
+ /** \param disconnect weak_ptr to a function that disconnects the handler
+ */
+ explicit
+ Connection(weak_ptr<function<void()>> disconnect);
+
+ template<typename Owner, typename ...TArgs>
+ friend class Signal;
+
+private:
+ /** \note The only shared_ptr to the disconnect function is stored in Signal<..>::Slot,
+ * and will be destructed if the handler is disconnected (through another Connection
+ * instance) or the Signal is destructed.
+ * Connection needs a weak_ptr instead of a shared_ptr to the disconnect function,
+ * because the disconnect function is bound with an iterator to the Slot,
+ * which is invalidated when the Slot is erased.
+ */
+ weak_ptr<function<void()>> m_disconnect;
+};
+
+} // namespace signal
+} // namespace util
+} // namespace ndn
+
+#endif // NDN_UTIL_SIGNAL_CONNECTION_HPP