ClickHouse/src/Common/EventCounter.h
2020-04-03 18:14:31 +03:00

48 lines
1004 B
C++

#pragma once
#include <cstdint>
#include <mutex>
#include <condition_variable>
/** Allow to subscribe for multiple events and wait for them one by one in arbitrary order.
*/
class EventCounter
{
private:
size_t events_happened = 0;
size_t events_waited = 0;
mutable std::mutex mutex;
std::condition_variable condvar;
public:
void notify()
{
{
std::lock_guard lock(mutex);
++events_happened;
}
condvar.notify_all();
}
void wait()
{
std::unique_lock lock(mutex);
condvar.wait(lock, [&]{ return events_happened > events_waited; });
++events_waited;
}
template <typename Duration>
bool waitFor(Duration && duration)
{
std::unique_lock lock(mutex);
if (condvar.wait(lock, std::forward<Duration>(duration), [&]{ return events_happened > events_waited; }))
{
++events_waited;
return true;
}
return false;
}
};