Line data    Source code

       1              : // Copyright (c) 2016-2022 The Bitcoin 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_THREADINTERRUPT_H
       6              : #define BITCOIN_UTIL_THREADINTERRUPT_H
       7              : 
       8              : #include <sync.h>
       9              : #include <threadsafety.h>
      10              : 
      11              : #include <atomic>
      12              : #include <chrono>
      13              : #include <condition_variable>
      14              : 
      15              : /**
      16              :  * A helper class for interruptible sleeps. Calling operator() will interrupt
      17              :  * any current sleep, and after that point operator bool() will return true
      18              :  * until reset.
      19              :  *
      20              :  * This class should not be used in a signal handler. It uses thread
      21              :  * synchronization primitives that are not safe to use with signals. If sending
      22              :  * an interrupt from a signal handler is necessary, the \ref SignalInterrupt
      23              :  * class can be used instead.
      24              :  */
      25              : 
      26              : class CThreadInterrupt
      27              : {
      28              : public:
      29              :     using Clock = std::chrono::steady_clock;
      30              : 
      31              :     CThreadInterrupt();
      32              : 
      33          633 :     virtual ~CThreadInterrupt() = default;
      34              : 
      35              :     /// Return true if `operator()()` has been called.
      36              :     virtual bool interrupted() const;
      37              : 
      38              :     /// An alias for `interrupted()`.
      39              :     virtual explicit operator bool() const;
      40              : 
      41              :     /// Interrupt any sleeps. After this `interrupted()` will return `true`.
      42              :     virtual void operator()() EXCLUSIVE_LOCKS_REQUIRED(!mut);
      43              : 
      44              :     /// Reset to an non-interrupted state.
      45              :     virtual void reset();
      46              : 
      47              :     /// Sleep for the given duration.
      48              :     /// @retval true The time passed.
      49              :     /// @retval false The sleep was interrupted.
      50              :     virtual bool sleep_for(Clock::duration rel_time) EXCLUSIVE_LOCKS_REQUIRED(!mut);
      51              : 
      52              : private:
      53              :     std::condition_variable cond;
      54              :     Mutex mut;
      55              :     std::atomic<bool> flag;
      56              : };
      57              : 
      58              : #endif // BITCOIN_UTIL_THREADINTERRUPT_H