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