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
11 #include "webrtc/base/signalthread.h"
12
13 #include "webrtc/base/common.h"
14
15 namespace rtc {
16
17 ///////////////////////////////////////////////////////////////////////////////
18 // SignalThread
19 ///////////////////////////////////////////////////////////////////////////////
20
SignalThread()21 SignalThread::SignalThread()
22 : main_(Thread::Current()),
23 worker_(this),
24 state_(kInit),
25 refcount_(1) {
26 main_->SignalQueueDestroyed.connect(this,
27 &SignalThread::OnMainThreadDestroyed);
28 worker_.SetName("SignalThread", this);
29 }
30
~SignalThread()31 SignalThread::~SignalThread() {
32 ASSERT(refcount_ == 0);
33 }
34
SetName(const std::string & name,const void * obj)35 bool SignalThread::SetName(const std::string& name, const void* obj) {
36 EnterExit ee(this);
37 ASSERT(main_->IsCurrent());
38 ASSERT(kInit == state_);
39 return worker_.SetName(name, obj);
40 }
41
Start()42 void SignalThread::Start() {
43 EnterExit ee(this);
44 ASSERT(main_->IsCurrent());
45 if (kInit == state_ || kComplete == state_) {
46 state_ = kRunning;
47 OnWorkStart();
48 worker_.Start();
49 } else {
50 ASSERT(false);
51 }
52 }
53
Destroy(bool wait)54 void SignalThread::Destroy(bool wait) {
55 EnterExit ee(this);
56 ASSERT(main_->IsCurrent());
57 if ((kInit == state_) || (kComplete == state_)) {
58 refcount_--;
59 } else if (kRunning == state_ || kReleasing == state_) {
60 state_ = kStopping;
61 // OnWorkStop() must follow Quit(), so that when the thread wakes up due to
62 // OWS(), ContinueWork() will return false.
63 worker_.Quit();
64 OnWorkStop();
65 if (wait) {
66 // Release the thread's lock so that it can return from ::Run.
67 cs_.Leave();
68 worker_.Stop();
69 cs_.Enter();
70 refcount_--;
71 }
72 } else {
73 ASSERT(false);
74 }
75 }
76
Release()77 void SignalThread::Release() {
78 EnterExit ee(this);
79 ASSERT(main_->IsCurrent());
80 if (kComplete == state_) {
81 refcount_--;
82 } else if (kRunning == state_) {
83 state_ = kReleasing;
84 } else {
85 // if (kInit == state_) use Destroy()
86 ASSERT(false);
87 }
88 }
89
ContinueWork()90 bool SignalThread::ContinueWork() {
91 EnterExit ee(this);
92 ASSERT(worker_.IsCurrent());
93 return worker_.ProcessMessages(0);
94 }
95
OnMessage(Message * msg)96 void SignalThread::OnMessage(Message *msg) {
97 EnterExit ee(this);
98 if (ST_MSG_WORKER_DONE == msg->message_id) {
99 ASSERT(main_->IsCurrent());
100 OnWorkDone();
101 bool do_delete = false;
102 if (kRunning == state_) {
103 state_ = kComplete;
104 } else {
105 do_delete = true;
106 }
107 if (kStopping != state_) {
108 // Before signaling that the work is done, make sure that the worker
109 // thread actually is done. We got here because DoWork() finished and
110 // Run() posted the ST_MSG_WORKER_DONE message. This means the worker
111 // thread is about to go away anyway, but sometimes it doesn't actually
112 // finish before SignalWorkDone is processed, and for a reusable
113 // SignalThread this makes an assert in thread.cc fire.
114 //
115 // Calling Stop() on the worker ensures that the OS thread that underlies
116 // the worker will finish, and will be set to NULL, enabling us to call
117 // Start() again.
118 worker_.Stop();
119 SignalWorkDone(this);
120 }
121 if (do_delete) {
122 refcount_--;
123 }
124 }
125 }
126
~Worker()127 SignalThread::Worker::~Worker() {
128 Stop();
129 }
130
Run()131 void SignalThread::Worker::Run() {
132 parent_->Run();
133 }
134
Run()135 void SignalThread::Run() {
136 DoWork();
137 {
138 EnterExit ee(this);
139 if (main_) {
140 main_->Post(this, ST_MSG_WORKER_DONE);
141 }
142 }
143 }
144
OnMainThreadDestroyed()145 void SignalThread::OnMainThreadDestroyed() {
146 EnterExit ee(this);
147 main_ = NULL;
148 }
149
150 } // namespace rtc
151