deadbeef | 8290ddf | 2017-07-11 16:56:05 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Copyright 2004 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 | |
Steve Anton | 10542f2 | 2019-01-11 09:11:00 -0800 | [diff] [blame] | 11 | #ifndef RTC_BASE_SIGNAL_THREAD_H_ |
| 12 | #define RTC_BASE_SIGNAL_THREAD_H_ |
deadbeef | 8290ddf | 2017-07-11 16:56:05 -0700 | [diff] [blame] | 13 | |
| 14 | #include <string> |
| 15 | |
Mirko Bonadei | 92ea95e | 2017-09-15 06:47:31 +0200 | [diff] [blame] | 16 | #include "rtc_base/checks.h" |
Steve Anton | 10542f2 | 2019-01-11 09:11:00 -0800 | [diff] [blame] | 17 | #include "rtc_base/constructor_magic.h" |
| 18 | #include "rtc_base/critical_section.h" |
| 19 | #include "rtc_base/message_handler.h" |
Yves Gerey | 988cc08 | 2018-10-23 12:03:01 +0200 | [diff] [blame] | 20 | #include "rtc_base/third_party/sigslot/sigslot.h" |
| 21 | #include "rtc_base/thread.h" |
| 22 | #include "rtc_base/thread_annotations.h" |
deadbeef | 8290ddf | 2017-07-11 16:56:05 -0700 | [diff] [blame] | 23 | |
| 24 | namespace rtc { |
| 25 | |
| 26 | /////////////////////////////////////////////////////////////////////////////// |
| 27 | // SignalThread - Base class for worker threads. The main thread should call |
| 28 | // Start() to begin work, and then follow one of these models: |
| 29 | // Normal: Wait for SignalWorkDone, and then call Release to destroy. |
| 30 | // Cancellation: Call Release(true), to abort the worker thread. |
| 31 | // Fire-and-forget: Call Release(false), which allows the thread to run to |
| 32 | // completion, and then self-destruct without further notification. |
| 33 | // Periodic tasks: Wait for SignalWorkDone, then eventually call Start() |
| 34 | // again to repeat the task. When the instance isn't needed anymore, |
| 35 | // call Release. DoWork, OnWorkStart and OnWorkStop are called again, |
| 36 | // on a new thread. |
| 37 | // The subclass should override DoWork() to perform the background task. By |
| 38 | // periodically calling ContinueWork(), it can check for cancellation. |
| 39 | // OnWorkStart and OnWorkDone can be overridden to do pre- or post-work |
| 40 | // tasks in the context of the main thread. |
| 41 | /////////////////////////////////////////////////////////////////////////////// |
| 42 | |
Yves Gerey | 665174f | 2018-06-19 15:03:05 +0200 | [diff] [blame] | 43 | class SignalThread : public sigslot::has_slots<>, protected MessageHandler { |
deadbeef | 8290ddf | 2017-07-11 16:56:05 -0700 | [diff] [blame] | 44 | public: |
Niels Möller | 77d3711 | 2018-01-15 12:59:43 +0100 | [diff] [blame] | 45 | SignalThread(); |
deadbeef | 8290ddf | 2017-07-11 16:56:05 -0700 | [diff] [blame] | 46 | |
| 47 | // Context: Main Thread. Call before Start to change the worker's name. |
| 48 | bool SetName(const std::string& name, const void* obj); |
| 49 | |
| 50 | // Context: Main Thread. Call to begin the worker thread. |
| 51 | void Start(); |
| 52 | |
| 53 | // Context: Main Thread. If the worker thread is not running, deletes the |
| 54 | // object immediately. Otherwise, asks the worker thread to abort processing, |
| 55 | // and schedules the object to be deleted once the worker exits. |
| 56 | // SignalWorkDone will not be signalled. If wait is true, does not return |
| 57 | // until the thread is deleted. |
| 58 | void Destroy(bool wait); |
| 59 | |
| 60 | // Context: Main Thread. If the worker thread is complete, deletes the |
| 61 | // object immediately. Otherwise, schedules the object to be deleted once |
| 62 | // the worker thread completes. SignalWorkDone will be signalled. |
| 63 | void Release(); |
| 64 | |
| 65 | // Context: Main Thread. Signalled when work is complete. |
Yves Gerey | 665174f | 2018-06-19 15:03:05 +0200 | [diff] [blame] | 66 | sigslot::signal1<SignalThread*> SignalWorkDone; |
deadbeef | 8290ddf | 2017-07-11 16:56:05 -0700 | [diff] [blame] | 67 | |
| 68 | enum { ST_MSG_WORKER_DONE, ST_MSG_FIRST_AVAILABLE }; |
| 69 | |
| 70 | protected: |
| 71 | ~SignalThread() override; |
| 72 | |
| 73 | Thread* worker() { return &worker_; } |
| 74 | |
| 75 | // Context: Main Thread. Subclass should override to do pre-work setup. |
Yves Gerey | 665174f | 2018-06-19 15:03:05 +0200 | [diff] [blame] | 76 | virtual void OnWorkStart() {} |
deadbeef | 8290ddf | 2017-07-11 16:56:05 -0700 | [diff] [blame] | 77 | |
| 78 | // Context: Worker Thread. Subclass should override to do work. |
| 79 | virtual void DoWork() = 0; |
| 80 | |
| 81 | // Context: Worker Thread. Subclass should call periodically to |
| 82 | // dispatch messages and determine if the thread should terminate. |
| 83 | bool ContinueWork(); |
| 84 | |
| 85 | // Context: Worker Thread. Subclass should override when extra work is |
| 86 | // needed to abort the worker thread. |
Yves Gerey | 665174f | 2018-06-19 15:03:05 +0200 | [diff] [blame] | 87 | virtual void OnWorkStop() {} |
deadbeef | 8290ddf | 2017-07-11 16:56:05 -0700 | [diff] [blame] | 88 | |
| 89 | // Context: Main Thread. Subclass should override to do post-work cleanup. |
Yves Gerey | 665174f | 2018-06-19 15:03:05 +0200 | [diff] [blame] | 90 | virtual void OnWorkDone() {} |
deadbeef | 8290ddf | 2017-07-11 16:56:05 -0700 | [diff] [blame] | 91 | |
| 92 | // Context: Any Thread. If subclass overrides, be sure to call the base |
| 93 | // implementation. Do not use (message_id < ST_MSG_FIRST_AVAILABLE) |
| 94 | void OnMessage(Message* msg) override; |
| 95 | |
| 96 | private: |
| 97 | enum State { |
Yves Gerey | 665174f | 2018-06-19 15:03:05 +0200 | [diff] [blame] | 98 | kInit, // Initialized, but not started |
| 99 | kRunning, // Started and doing work |
| 100 | kReleasing, // Same as running, but to be deleted when work is done |
| 101 | kComplete, // Work is done |
| 102 | kStopping, // Work is being interrupted |
deadbeef | 8290ddf | 2017-07-11 16:56:05 -0700 | [diff] [blame] | 103 | }; |
| 104 | |
| 105 | class Worker : public Thread { |
| 106 | public: |
Taylor Brandstetter | 0867260 | 2018-03-02 15:20:33 -0800 | [diff] [blame] | 107 | explicit Worker(SignalThread* parent); |
deadbeef | 8290ddf | 2017-07-11 16:56:05 -0700 | [diff] [blame] | 108 | ~Worker() override; |
| 109 | void Run() override; |
Niels Möller | 8909a63 | 2018-09-06 08:42:44 +0200 | [diff] [blame] | 110 | bool IsProcessingMessagesForTesting() override; |
deadbeef | 8290ddf | 2017-07-11 16:56:05 -0700 | [diff] [blame] | 111 | |
| 112 | private: |
| 113 | SignalThread* parent_; |
| 114 | |
| 115 | RTC_DISALLOW_IMPLICIT_CONSTRUCTORS(Worker); |
| 116 | }; |
| 117 | |
danilchap | 3c6abd2 | 2017-09-06 05:46:29 -0700 | [diff] [blame] | 118 | class RTC_SCOPED_LOCKABLE EnterExit { |
deadbeef | 8290ddf | 2017-07-11 16:56:05 -0700 | [diff] [blame] | 119 | public: |
danilchap | 3c6abd2 | 2017-09-06 05:46:29 -0700 | [diff] [blame] | 120 | explicit EnterExit(SignalThread* t) RTC_EXCLUSIVE_LOCK_FUNCTION(t->cs_) |
deadbeef | 8290ddf | 2017-07-11 16:56:05 -0700 | [diff] [blame] | 121 | : t_(t) { |
| 122 | t_->cs_.Enter(); |
| 123 | // If refcount_ is zero then the object has already been deleted and we |
| 124 | // will be double-deleting it in ~EnterExit()! (shouldn't happen) |
| 125 | RTC_DCHECK_NE(0, t_->refcount_); |
| 126 | ++t_->refcount_; |
| 127 | } |
danilchap | 3c6abd2 | 2017-09-06 05:46:29 -0700 | [diff] [blame] | 128 | ~EnterExit() RTC_UNLOCK_FUNCTION() { |
deadbeef | 8290ddf | 2017-07-11 16:56:05 -0700 | [diff] [blame] | 129 | bool d = (0 == --t_->refcount_); |
| 130 | t_->cs_.Leave(); |
| 131 | if (d) |
| 132 | delete t_; |
| 133 | } |
| 134 | |
| 135 | private: |
| 136 | SignalThread* t_; |
| 137 | |
| 138 | RTC_DISALLOW_IMPLICIT_CONSTRUCTORS(EnterExit); |
| 139 | }; |
| 140 | |
| 141 | void Run(); |
| 142 | void OnMainThreadDestroyed(); |
| 143 | |
| 144 | Thread* main_; |
| 145 | Worker worker_; |
| 146 | CriticalSection cs_; |
| 147 | State state_; |
| 148 | int refcount_; |
| 149 | |
| 150 | RTC_DISALLOW_COPY_AND_ASSIGN(SignalThread); |
| 151 | }; |
| 152 | |
| 153 | /////////////////////////////////////////////////////////////////////////////// |
| 154 | |
| 155 | } // namespace rtc |
| 156 | |
Steve Anton | 10542f2 | 2019-01-11 09:11:00 -0800 | [diff] [blame] | 157 | #endif // RTC_BASE_SIGNAL_THREAD_H_ |