1 // Copyright 2022 gRPC authors. 2 // 3 // Licensed under the Apache License, Version 2.0 (the "License"); 4 // you may not use this file except in compliance with the License. 5 // You may obtain a copy of the License at 6 // 7 // http://www.apache.org/licenses/LICENSE-2.0 8 // 9 // Unless required by applicable law or agreed to in writing, software 10 // distributed under the License is distributed on an "AS IS" BASIS, 11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 // See the License for the specific language governing permissions and 13 // limitations under the License. 14 15 #ifndef GRPC_SRC_CORE_LIB_PROMISE_SLEEP_H 16 #define GRPC_SRC_CORE_LIB_PROMISE_SLEEP_H 17 18 #include <grpc/event_engine/event_engine.h> 19 #include <grpc/support/port_platform.h> 20 21 #include <atomic> 22 #include <utility> 23 24 #include "absl/status/status.h" 25 #include "src/core/lib/promise/activity.h" 26 #include "src/core/lib/promise/poll.h" 27 #include "src/core/util/time.h" 28 29 namespace grpc_core { 30 31 // Promise that sleeps until a deadline and then finishes. 32 class Sleep final { 33 public: 34 explicit Sleep(Timestamp deadline); Sleep(Duration timeout)35 explicit Sleep(Duration timeout) : Sleep(Timestamp::Now() + timeout) {} 36 ~Sleep(); 37 38 Sleep(const Sleep&) = delete; 39 Sleep& operator=(const Sleep&) = delete; Sleep(Sleep && other)40 Sleep(Sleep&& other) noexcept 41 : deadline_(other.deadline_), 42 closure_(std::exchange(other.closure_, nullptr)) {} 43 Sleep& operator=(Sleep&& other) noexcept { 44 deadline_ = other.deadline_; 45 std::swap(closure_, other.closure_); 46 return *this; 47 }; 48 49 Poll<absl::Status> operator()(); 50 51 private: 52 class ActiveClosure final 53 : public grpc_event_engine::experimental::EventEngine::Closure { 54 public: 55 explicit ActiveClosure(Timestamp deadline); 56 57 void Run() override; 58 // After calling Cancel, it's no longer safe to access this object. 59 void Cancel(); 60 61 bool HasRun() const; 62 63 private: 64 bool Unref(); 65 66 Waker waker_; 67 // One ref dropped by Run(), the other by Cancel(). 68 std::atomic<int> refs_{2}; 69 grpc_event_engine::experimental::EventEngine::TaskHandle timer_handle_; 70 }; 71 72 Timestamp deadline_; 73 ActiveClosure* closure_{nullptr}; 74 }; 75 76 } // namespace grpc_core 77 78 #endif // GRPC_SRC_CORE_LIB_PROMISE_SLEEP_H 79