Make some more sleeps interruptable.

[nageru] / quittable_sleeper.h

diff --git a/quittable_sleeper.h b/quittable_sleeper.h
new file mode 100644 (file)
index 0000000..ba00e73
--- /dev/null
+++ b/quittable_sleeper.h
@@ -0,0 +1,59 @@
+#ifndef _QUITTABLE_SLEEPER
+#define _QUITTABLE_SLEEPER 1
+
+// A class that assists with fast shutdown of threads. You can set
+// a flag that says the thread should quit, which it can then check
+// in a loop -- and if the thread sleeps (using the sleep_* functions
+// on the class), that sleep will immediately be aborted.
+//
+// All member functions on this class are thread-safe.
+
+#include <chrono>
+#include <mutex>
+
+class QuittableSleeper {
+public:
+       void quit()
+       {
+               std::lock_guard<std::mutex> l(mu);
+               should_quit_var = true;
+               quit_cond.notify_all();
+       }
+
+       void unquit()
+       {
+               std::lock_guard<std::mutex> l(mu);
+               should_quit_var = false;
+       }
+
+       bool should_quit() const
+       {
+               std::lock_guard<std::mutex> l(mu);
+               return should_quit_var;
+       }
+
+       template<class Rep, class Period>
+       void sleep_for(const std::chrono::duration<Rep, Period> &duration)
+       {
+               std::chrono::steady_clock::time_point t =
+                       std::chrono::steady_clock::now() +
+                       std::chrono::duration_cast<std::chrono::steady_clock::duration>(duration);
+               sleep_until(t);
+       }
+
+       template<class Clock, class Duration>
+       void sleep_until(const std::chrono::time_point<Clock, Duration> &t)
+       {
+               std::unique_lock<std::mutex> lock(mu);
+               quit_cond.wait_until(lock, t, [this]{
+                       return should_quit_var;
+               });
+       }
+
+private:
+       mutable std::mutex mu;
+       bool should_quit_var = false;
+       std::condition_variable quit_cond;
+};
+
+#endif  // !defined(_QUITTABLE_SLEEPER)