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1 /* | 1 /* |
2 * Copyright 2004 The WebRTC Project Authors. All rights reserved. | 2 * Copyright 2004 The WebRTC Project Authors. All rights reserved. |
3 * | 3 * |
4 * Use of this source code is governed by a BSD-style license | 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 | 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 | 6 * tree. An additional intellectual property rights grant can be found |
7 * in the file PATENTS. All contributing project authors may | 7 * in the file PATENTS. All contributing project authors may |
8 * be found in the AUTHORS file in the root of the source tree. | 8 * be found in the AUTHORS file in the root of the source tree. |
9 */ | 9 */ |
10 | 10 |
11 #ifndef WEBRTC_BASE_SIGNALTHREAD_H_ | 11 #ifndef WEBRTC_BASE_SIGNALTHREAD_H_ |
12 #define WEBRTC_BASE_SIGNALTHREAD_H_ | 12 #define WEBRTC_BASE_SIGNALTHREAD_H_ |
13 | 13 |
14 #include <string> | |
15 | 14 |
16 #include "webrtc/base/checks.h" | 15 // This header is deprecated and is just left here temporarily during |
17 #include "webrtc/base/constructormagic.h" | 16 // refactoring. See https://bugs.webrtc.org/7634 for more details. |
18 #include "webrtc/base/nullsocketserver.h" | 17 #include "webrtc/rtc_base/signalthread.h" |
19 #include "webrtc/base/sigslot.h" | |
20 #include "webrtc/base/thread.h" | |
21 | |
22 namespace rtc { | |
23 | |
24 /////////////////////////////////////////////////////////////////////////////// | |
25 // SignalThread - Base class for worker threads. The main thread should call | |
26 // Start() to begin work, and then follow one of these models: | |
27 // Normal: Wait for SignalWorkDone, and then call Release to destroy. | |
28 // Cancellation: Call Release(true), to abort the worker thread. | |
29 // Fire-and-forget: Call Release(false), which allows the thread to run to | |
30 // completion, and then self-destruct without further notification. | |
31 // Periodic tasks: Wait for SignalWorkDone, then eventually call Start() | |
32 // again to repeat the task. When the instance isn't needed anymore, | |
33 // call Release. DoWork, OnWorkStart and OnWorkStop are called again, | |
34 // on a new thread. | |
35 // The subclass should override DoWork() to perform the background task. By | |
36 // periodically calling ContinueWork(), it can check for cancellation. | |
37 // OnWorkStart and OnWorkDone can be overridden to do pre- or post-work | |
38 // tasks in the context of the main thread. | |
39 /////////////////////////////////////////////////////////////////////////////// | |
40 | |
41 class SignalThread | |
42 : public sigslot::has_slots<>, | |
43 protected MessageHandler { | |
44 public: | |
45 explicit SignalThread(bool use_socket_server = true); | |
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. | |
66 sigslot::signal1<SignalThread *> SignalWorkDone; | |
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. | |
76 virtual void OnWorkStart() { } | |
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. | |
87 virtual void OnWorkStop() { } | |
88 | |
89 // Context: Main Thread. Subclass should override to do post-work cleanup. | |
90 virtual void OnWorkDone() { } | |
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 { | |
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 | |
103 }; | |
104 | |
105 class Worker : public Thread { | |
106 public: | |
107 explicit Worker(SignalThread* parent, bool use_socket_server) | |
108 : Thread(use_socket_server | |
109 ? SocketServer::CreateDefault() | |
110 : std::unique_ptr<SocketServer>(new NullSocketServer())), | |
111 parent_(parent) {} | |
112 ~Worker() override; | |
113 void Run() override; | |
114 bool IsProcessingMessages() override; | |
115 | |
116 private: | |
117 SignalThread* parent_; | |
118 | |
119 RTC_DISALLOW_IMPLICIT_CONSTRUCTORS(Worker); | |
120 }; | |
121 | |
122 class SCOPED_LOCKABLE EnterExit { | |
123 public: | |
124 explicit EnterExit(SignalThread* t) EXCLUSIVE_LOCK_FUNCTION(t->cs_) | |
125 : t_(t) { | |
126 t_->cs_.Enter(); | |
127 // If refcount_ is zero then the object has already been deleted and we | |
128 // will be double-deleting it in ~EnterExit()! (shouldn't happen) | |
129 RTC_DCHECK_NE(0, t_->refcount_); | |
130 ++t_->refcount_; | |
131 } | |
132 ~EnterExit() UNLOCK_FUNCTION() { | |
133 bool d = (0 == --t_->refcount_); | |
134 t_->cs_.Leave(); | |
135 if (d) | |
136 delete t_; | |
137 } | |
138 | |
139 private: | |
140 SignalThread* t_; | |
141 | |
142 RTC_DISALLOW_IMPLICIT_CONSTRUCTORS(EnterExit); | |
143 }; | |
144 | |
145 void Run(); | |
146 void OnMainThreadDestroyed(); | |
147 | |
148 Thread* main_; | |
149 Worker worker_; | |
150 CriticalSection cs_; | |
151 State state_; | |
152 int refcount_; | |
153 | |
154 RTC_DISALLOW_COPY_AND_ASSIGN(SignalThread); | |
155 }; | |
156 | |
157 /////////////////////////////////////////////////////////////////////////////// | |
158 | |
159 } // namespace rtc | |
160 | 18 |
161 #endif // WEBRTC_BASE_SIGNALTHREAD_H_ | 19 #endif // WEBRTC_BASE_SIGNALTHREAD_H_ |
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