Line data    Source code

       1             : // Copyright (c) 2020-2025 The Dash Core developers
       2             : // Distributed under the MIT software license, see the accompanying
       3             : // file COPYING or http://www.opensource.org/licenses/mit-license.php.
       4             : 
       5             : #ifndef BITCOIN_UTIL_WPIPE_H
       6             : #define BITCOIN_UTIL_WPIPE_H
       7             : 
       8             : #include <array>
       9             : #include <assert.h>
      10             : #include <atomic>
      11             : 
      12             : #ifndef WIN32
      13             : #define USE_WAKEUP_PIPE
      14             : #endif
      15             : 
      16             : class EdgeTriggeredEvents;
      17             : 
      18             : /**
      19             :  * A manager for abstracting logic surrounding wakeup pipes. Supported only on
      20             :  * platforms with a POSIX API. Disabled on Windows.
      21             :  */
      22             : class WakeupPipe
      23             : {
      24             : private:
      25             :     /* Iterate through m_pipe and ::close() them */
      26             :     void Close();
      27             : 
      28             : public:
      29             :     explicit WakeupPipe(EdgeTriggeredEvents* edge_trig_events);
      30             :     ~WakeupPipe();
      31             : 
      32        2821 :     bool IsValid() const { return m_valid; };
      33             : 
      34             :     /* Drain pipe of all contents */
      35             :     void Drain() const;
      36             :     /* Write a byte to the pipe */
      37             :     void Write();
      38             : 
      39             :     /* Used to wrap calls around m_need_wakeup toggling */
      40             :     template <typename Callable>
      41    29784563 :     void Toggle(Callable&& func)
      42             :     {
      43    29784563 :         assert(m_valid);
      44             : 
      45    29784563 :         m_need_wakeup = true;
      46    29784563 :         func();
      47    29784563 :         m_need_wakeup = false;
      48    29784563 :     }
      49             : 
      50             : public:
      51             :     /* File descriptors for read and write data channels */
      52             :     std::array<int, 2> m_pipe{{ -1, -1 }};
      53             :     /* Flag used to determine if Write() needs to be called. Used occasionally */
      54             :     std::atomic<bool> m_need_wakeup{false};
      55             : 
      56             : private:
      57             :     /* Instance validity flag set during construction */
      58             :     bool m_valid{false};
      59             :     /* Pointer to EdgeTriggeredEvents instance used for pipe (de)registration if using supported events modes */
      60             :     EdgeTriggeredEvents* m_edge_trig_events{nullptr};
      61             : };
      62             : 
      63             : #endif // BITCOIN_UTIL_WPIPE_H