// Copyright (c) 2016-present 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 <util/time.h>

#include <atomic>

#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.

 *

 * This class should not be used in a signal handler. It uses thread

 * synchronization primitives that are not safe to use with signals. If sending

 * an interrupt from a signal handler is necessary, the \ref SignalInterrupt

 * class can be used instead.

 */

class CThreadInterrupt

{

public:

    using Clock = std::chrono::steady_clock;

    CThreadInterrupt();

    virtual ~CThreadInterrupt() = default;

    /// Return true if `operator()()` has been called.

    virtual bool interrupted() const;

    /// An alias for `interrupted()`.

    virtual explicit operator bool() const;

    /// Interrupt any sleeps. After this `interrupted()` will return `true`.

    virtual void operator()() EXCLUSIVE_LOCKS_REQUIRED(!mut);

    /// Reset to an non-interrupted state.

    virtual void reset();

    /// Sleep for the given duration.

    /// @retval true The time passed.

    /// @retval false The sleep was interrupted.

    virtual 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