connection.hpp
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21 
22 #ifndef NDN_CXX_UTIL_SIGNAL_CONNECTION_HPP
23 #define NDN_CXX_UTIL_SIGNAL_CONNECTION_HPP
24 
26 
27 #include <boost/operators.hpp>
28 
29 namespace ndn::signal {
30 
31 using DisconnectFunction = std::function<void()>;
32 
37 class Connection : private boost::equality_comparable<Connection>
38 {
39 public:
40  constexpr
41  Connection() noexcept = default;
42 
50  void
51  disconnect();
52 
56  bool
57  isConnected() const noexcept
58  {
59  return !m_disconnect.expired();
60  }
61 
62 private:
63  explicit
64  Connection(weak_ptr<DisconnectFunction> disconnect) noexcept;
65 
66  template<typename Owner, typename... TArgs>
67  friend class Signal;
68 
69 private: // non-member operators
70  // NOTE: the following "hidden friend" operators are available via
71  // argument-dependent lookup only and must be defined inline.
72  // boost::equality_comparable provides != operator.
73 
80  friend bool
81  operator==(const Connection& lhs, const Connection& rhs) noexcept
82  {
83  return (!lhs.isConnected() && !rhs.isConnected()) ||
84  (!lhs.m_disconnect.owner_before(rhs.m_disconnect) &&
85  !rhs.m_disconnect.owner_before(lhs.m_disconnect));
86  }
87 
88 private:
96  weak_ptr<DisconnectFunction> m_disconnect;
97 };
98 
99 } // namespace ndn::signal
100 
101 #endif // NDN_CXX_UTIL_SIGNAL_CONNECTION_HPP
Represents a connection to a signal.
Definition: connection.hpp:38
constexpr Connection() noexcept=default
void disconnect()
Disconnects from the signal.
Definition: connection.cpp:32
friend bool operator==(const Connection &lhs, const Connection &rhs) noexcept
Compare for equality.
Definition: connection.hpp:81
bool isConnected() const noexcept
Check if connected to the signal.
Definition: connection.hpp:57
Provides a lightweight signal / event system.
Definition: signal.hpp:51
Common includes and macros used throughout the library.
std::function< void()> DisconnectFunction
Definition: connection.hpp:31