1 /* 2 * Copyright (c) 2021 The WebRTC project authors. All Rights Reserved. 3 * 4 * Use of this source code is governed by a BSD-style license 5 * that can be found in the LICENSE file in the root of the source 6 * tree. An additional intellectual property rights grant can be found 7 * in the file PATENTS. All contributing project authors may 8 * be found in the AUTHORS file in the root of the source tree. 9 */ 10 #ifndef NET_DCSCTP_TIMER_TASK_QUEUE_TIMEOUT_H_ 11 #define NET_DCSCTP_TIMER_TASK_QUEUE_TIMEOUT_H_ 12 13 #include <memory> 14 #include <utility> 15 16 #include "api/task_queue/pending_task_safety_flag.h" 17 #include "api/task_queue/task_queue_base.h" 18 #include "net/dcsctp/public/timeout.h" 19 20 namespace dcsctp { 21 22 // The TaskQueueTimeoutFactory creates `Timeout` instances, which schedules 23 // itself to be triggered on the provided `task_queue`, which may be a thread, 24 // an actual TaskQueue or something else which supports posting a delayed task. 25 // 26 // Note that each `DcSctpSocket` must have its own `TaskQueueTimeoutFactory`, 27 // as the `TimeoutID` are not unique among sockets. 28 // 29 // This class must outlive any created Timeout that it has created. Note that 30 // the `DcSctpSocket` will ensure that all Timeouts are deleted when the socket 31 // is destructed, so this means that this class must outlive the `DcSctpSocket`. 32 // 33 // This class, and the timeouts created it, are not thread safe. 34 class TaskQueueTimeoutFactory { 35 public: 36 // The `get_time` function must return the current time, relative to any 37 // epoch. Whenever a timeout expires, the `on_expired` callback will be 38 // triggered, and then the client should provided `timeout_id` to 39 // `DcSctpSocketInterface::HandleTimeout`. TaskQueueTimeoutFactory(webrtc::TaskQueueBase & task_queue,std::function<TimeMs ()> get_time,std::function<void (TimeoutID timeout_id)> on_expired)40 TaskQueueTimeoutFactory(webrtc::TaskQueueBase& task_queue, 41 std::function<TimeMs()> get_time, 42 std::function<void(TimeoutID timeout_id)> on_expired) 43 : task_queue_(task_queue), 44 get_time_(std::move(get_time)), 45 on_expired_(std::move(on_expired)) {} 46 47 // Creates an implementation of `Timeout`. 48 std::unique_ptr<Timeout> CreateTimeout( 49 webrtc::TaskQueueBase::DelayPrecision precision = 50 webrtc::TaskQueueBase::DelayPrecision::kLow) { 51 return std::make_unique<TaskQueueTimeout>(*this, precision); 52 } 53 54 private: 55 class TaskQueueTimeout : public Timeout { 56 public: 57 TaskQueueTimeout(TaskQueueTimeoutFactory& parent, 58 webrtc::TaskQueueBase::DelayPrecision precision); 59 ~TaskQueueTimeout(); 60 61 void Start(DurationMs duration_ms, TimeoutID timeout_id) override; 62 void Stop() override; 63 64 private: 65 TaskQueueTimeoutFactory& parent_; 66 const webrtc::TaskQueueBase::DelayPrecision precision_; 67 // A safety flag to ensure that posted tasks to the task queue don't 68 // reference these object when they go out of scope. Note that this safety 69 // flag will be re-created if the scheduled-but-not-yet-expired task is not 70 // to be run. This happens when there is a posted delayed task with an 71 // expiration time _further away_ than what is now the expected expiration 72 // time. In this scenario, a new delayed task has to be posted with a 73 // shorter duration and the old task has to be forgotten. 74 rtc::scoped_refptr<webrtc::PendingTaskSafetyFlag> pending_task_safety_flag_; 75 // The time when the posted delayed task is set to expire. Will be set to 76 // the infinite future if there is no such task running. 77 TimeMs posted_task_expiration_ = TimeMs::InfiniteFuture(); 78 // The time when the timeout expires. It will be set to the infinite future 79 // if the timeout is not running/not started. 80 TimeMs timeout_expiration_ = TimeMs::InfiniteFuture(); 81 // The current timeout ID that will be reported when expired. 82 TimeoutID timeout_id_ = TimeoutID(0); 83 }; 84 85 RTC_NO_UNIQUE_ADDRESS webrtc::SequenceChecker thread_checker_; 86 webrtc::TaskQueueBase& task_queue_; 87 const std::function<TimeMs()> get_time_; 88 const std::function<void(TimeoutID)> on_expired_; 89 }; 90 } // namespace dcsctp 91 92 #endif // NET_DCSCTP_TIMER_TASK_QUEUE_TIMEOUT_H_ 93