1 // Copyright (c) 2010 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4
5 #include "base/threading/simple_thread.h"
6
7 #include "base/logging.h"
8 #include "base/strings/string_number_conversions.h"
9 #include "base/threading/platform_thread.h"
10 #include "base/threading/thread_restrictions.h"
11
12 namespace base {
13
SimpleThread(const std::string & name_prefix)14 SimpleThread::SimpleThread(const std::string& name_prefix)
15 : name_prefix_(name_prefix), name_(name_prefix),
16 thread_(), event_(true, false), tid_(0), joined_(false) {
17 }
18
SimpleThread(const std::string & name_prefix,const Options & options)19 SimpleThread::SimpleThread(const std::string& name_prefix,
20 const Options& options)
21 : name_prefix_(name_prefix), name_(name_prefix), options_(options),
22 thread_(), event_(true, false), tid_(0), joined_(false) {
23 }
24
~SimpleThread()25 SimpleThread::~SimpleThread() {
26 DCHECK(HasBeenStarted()) << "SimpleThread was never started.";
27 DCHECK(HasBeenJoined()) << "SimpleThread destroyed without being Join()ed.";
28 }
29
Start()30 void SimpleThread::Start() {
31 DCHECK(!HasBeenStarted()) << "Tried to Start a thread multiple times.";
32 bool success = PlatformThread::Create(options_.stack_size(), this, &thread_);
33 DCHECK(success);
34 base::ThreadRestrictions::ScopedAllowWait allow_wait;
35 event_.Wait(); // Wait for the thread to complete initialization.
36 }
37
Join()38 void SimpleThread::Join() {
39 DCHECK(HasBeenStarted()) << "Tried to Join a never-started thread.";
40 DCHECK(!HasBeenJoined()) << "Tried to Join a thread multiple times.";
41 PlatformThread::Join(thread_);
42 joined_ = true;
43 }
44
HasBeenStarted()45 bool SimpleThread::HasBeenStarted() {
46 base::ThreadRestrictions::ScopedAllowWait allow_wait;
47 return event_.IsSignaled();
48 }
49
ThreadMain()50 void SimpleThread::ThreadMain() {
51 tid_ = PlatformThread::CurrentId();
52 // Construct our full name of the form "name_prefix_/TID".
53 name_.push_back('/');
54 name_.append(IntToString(tid_));
55 PlatformThread::SetName(name_.c_str());
56
57 // We've initialized our new thread, signal that we're done to Start().
58 event_.Signal();
59
60 Run();
61 }
62
DelegateSimpleThread(Delegate * delegate,const std::string & name_prefix)63 DelegateSimpleThread::DelegateSimpleThread(Delegate* delegate,
64 const std::string& name_prefix)
65 : SimpleThread(name_prefix),
66 delegate_(delegate) {
67 }
68
DelegateSimpleThread(Delegate * delegate,const std::string & name_prefix,const Options & options)69 DelegateSimpleThread::DelegateSimpleThread(Delegate* delegate,
70 const std::string& name_prefix,
71 const Options& options)
72 : SimpleThread(name_prefix, options),
73 delegate_(delegate) {
74 }
75
~DelegateSimpleThread()76 DelegateSimpleThread::~DelegateSimpleThread() {
77 }
78
Run()79 void DelegateSimpleThread::Run() {
80 DCHECK(delegate_) << "Tried to call Run without a delegate (called twice?)";
81 delegate_->Run();
82 delegate_ = NULL;
83 }
84
DelegateSimpleThreadPool(const std::string & name_prefix,int num_threads)85 DelegateSimpleThreadPool::DelegateSimpleThreadPool(
86 const std::string& name_prefix,
87 int num_threads)
88 : name_prefix_(name_prefix),
89 num_threads_(num_threads),
90 dry_(true, false) {
91 }
92
~DelegateSimpleThreadPool()93 DelegateSimpleThreadPool::~DelegateSimpleThreadPool() {
94 DCHECK(threads_.empty());
95 DCHECK(delegates_.empty());
96 DCHECK(!dry_.IsSignaled());
97 }
98
Start()99 void DelegateSimpleThreadPool::Start() {
100 DCHECK(threads_.empty()) << "Start() called with outstanding threads.";
101 for (int i = 0; i < num_threads_; ++i) {
102 DelegateSimpleThread* thread = new DelegateSimpleThread(this, name_prefix_);
103 thread->Start();
104 threads_.push_back(thread);
105 }
106 }
107
JoinAll()108 void DelegateSimpleThreadPool::JoinAll() {
109 DCHECK(!threads_.empty()) << "JoinAll() called with no outstanding threads.";
110
111 // Tell all our threads to quit their worker loop.
112 AddWork(NULL, num_threads_);
113
114 // Join and destroy all the worker threads.
115 for (int i = 0; i < num_threads_; ++i) {
116 threads_[i]->Join();
117 delete threads_[i];
118 }
119 threads_.clear();
120 DCHECK(delegates_.empty());
121 }
122
AddWork(Delegate * delegate,int repeat_count)123 void DelegateSimpleThreadPool::AddWork(Delegate* delegate, int repeat_count) {
124 AutoLock locked(lock_);
125 for (int i = 0; i < repeat_count; ++i)
126 delegates_.push(delegate);
127 // If we were empty, signal that we have work now.
128 if (!dry_.IsSignaled())
129 dry_.Signal();
130 }
131
Run()132 void DelegateSimpleThreadPool::Run() {
133 Delegate* work = NULL;
134
135 while (true) {
136 dry_.Wait();
137 {
138 AutoLock locked(lock_);
139 if (!dry_.IsSignaled())
140 continue;
141
142 DCHECK(!delegates_.empty());
143 work = delegates_.front();
144 delegates_.pop();
145
146 // Signal to any other threads that we're currently out of work.
147 if (delegates_.empty())
148 dry_.Reset();
149 }
150
151 // A NULL delegate pointer signals us to quit.
152 if (!work)
153 break;
154
155 work->Run();
156 }
157 }
158
159 } // namespace base
160