ceph/src/seastar/include/seastar/core/sleep.hh

   1 /*
   2  * This file is open source software, licensed to you under the terms
   3  * of the Apache License, Version 2.0 (the "License").  See the NOTICE file
   4  * distributed with this work for additional information regarding copyright
   5  * ownership.  You may not use this file except in compliance with the License.
   6  *
   7  * You may obtain a copy of the License at
   8  *
   9  *   http://www.apache.org/licenses/LICENSE-2.0
  10  *
  11  * Unless required by applicable law or agreed to in writing,
  12  * software distributed under the License is distributed on an
  13  * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
  14  * KIND, either express or implied.  See the License for the
  15  * specific language governing permissions and limitations
  16  * under the License.
  17  */
  18
  19 /*
  20  * Copyright (C) 2015 Cloudius Systems, Ltd.
  21  */
  22
  23 #pragma once
  24
  25 #include <chrono>
  26 #include <functional>
  27
  28 #include <seastar/core/abort_source.hh>
  29 #include <seastar/core/future.hh>
  30 #include <seastar/core/lowres_clock.hh>
  31 #include <seastar/core/timer.hh>
  32
  33 namespace seastar {
  34
  35 /// \file
  36
  37 /// Returns a future which completes after a specified time has elapsed.
  38 ///
  39 /// \param dur minimum amount of time before the returned future becomes
  40 ///            ready.
  41 /// \return A \ref future which becomes ready when the sleep duration elapses.
  42 template <typename Clock = steady_clock_type, typename Rep, typename Period>
  43 future<> sleep(std::chrono::duration<Rep, Period> dur) {
  44     struct sleeper {
  45         promise<> done;
  46         timer<Clock> tmr;
  47         sleeper(std::chrono::duration<Rep, Period> dur)
  48             : tmr([this] { done.set_value(); })
  49         {
  50             tmr.arm(dur);
  51         }
  52     };
  53     sleeper *s = new sleeper(dur);
  54     future<> fut = s->done.get_future();
  55     return fut.then([s] { delete s; });
  56 }
  57
  58 /// exception that is thrown when application is in process of been stopped
  59 class sleep_aborted : public abort_requested_exception {
  60 public:
  61     /// Reports the exception reason.
  62     virtual const char* what() const noexcept {
  63         return "Sleep is aborted";
  64     }
  65 };
  66
  67 /// Returns a future which completes after a specified time has elapsed
  68 /// or throws \ref sleep_aborted exception if application is aborted
  69 ///
  70 /// \param dur minimum amount of time before the returned future becomes
  71 ///            ready.
  72 /// \return A \ref future which becomes ready when the sleep duration elapses.
  73 template <typename Clock = steady_clock_type>
  74 future<> sleep_abortable(typename Clock::duration dur);
  75
  76 extern template future<> sleep_abortable<steady_clock_type>(typename steady_clock_type::duration);
  77 extern template future<> sleep_abortable<lowres_clock>(typename lowres_clock::duration);
  78
  79 /// Returns a future which completes after a specified time has elapsed
  80 /// or throws \ref sleep_aborted exception if the sleep is aborted.
  81 ///
  82 /// \param dur minimum amount of time before the returned future becomes
  83 ///            ready.
  84 /// \param as the \ref abort_source that eventually notifies that the sleep
  85 ///            should be aborted.
  86 /// \return A \ref future which becomes ready when the sleep duration elapses.
  87 template <typename Clock = steady_clock_type>
  88 future<> sleep_abortable(typename Clock::duration dur, abort_source& as);
  89
  90 extern template future<> sleep_abortable<steady_clock_type>(typename steady_clock_type::duration, abort_source&);
  91 extern template future<> sleep_abortable<lowres_clock>(typename lowres_clock::duration, abort_source&);
  92
  93 }