util: move threadinterrupt into util

src/util/threadinterrupt.h

@@ -0,0 +1,36 @@
+// Copyright (c) 2016-2021 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#ifndef BITCOIN_UTIL_THREADINTERRUPT_H
+#define BITCOIN_UTIL_THREADINTERRUPT_H
+
+#include <sync.h>
+#include <threadsafety.h>
+
+#include <atomic>
+#include <chrono>
+#include <condition_variable>
+
+/*
+    A helper class for interruptible sleeps. Calling operator() will interrupt
+    any current sleep, and after that point operator bool() will return true
+    until reset.
+*/
+class CThreadInterrupt
+{
+public:
+    using Clock = std::chrono::steady_clock;
+    CThreadInterrupt();
+    explicit operator bool() const;
+    void operator()() EXCLUSIVE_LOCKS_REQUIRED(!mut);
+    void reset();
+    bool sleep_for(Clock::duration rel_time) EXCLUSIVE_LOCKS_REQUIRED(!mut);
+
+private:
+    std::condition_variable cond;
+    Mutex mut;
+    std::atomic<bool> flag;
+};
+
+#endif // BITCOIN_UTIL_THREADINTERRUPT_H