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1 // Copyright (c) 2010 The Chromium Authors. All rights reserved. | 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 | 2 // Use of this source code is governed by a BSD-style license that can be |
3 // found in the LICENSE file. | 3 // found in the LICENSE file. |
4 | 4 |
5 #include "base/threading/simple_thread.h" | 5 #include "base/threading/simple_thread.h" |
6 | 6 |
7 #include "base/logging.h" | |
8 #include "base/strings/string_number_conversions.h" | 7 #include "base/strings/string_number_conversions.h" |
9 #include "base/threading/platform_thread.h" | 8 #include "base/threading/platform_thread.h" |
10 #include "base/threading/thread_restrictions.h" | 9 #include "base/threading/thread_restrictions.h" |
11 | 10 |
12 namespace base { | 11 namespace base { |
13 | 12 |
14 SimpleThread::SimpleThread(const std::string& name_prefix) | 13 SimpleThread::SimpleThread(const std::string& name_prefix) |
15 : name_prefix_(name_prefix), | 14 : SimpleThread(name_prefix, Options()) {} |
16 name_(name_prefix), | |
17 thread_(), | |
18 event_(WaitableEvent::ResetPolicy::MANUAL, | |
19 WaitableEvent::InitialState::NOT_SIGNALED), | |
20 tid_(0), | |
21 joined_(false) {} | |
22 | 15 |
23 SimpleThread::SimpleThread(const std::string& name_prefix, | 16 SimpleThread::SimpleThread(const std::string& name_prefix, |
24 const Options& options) | 17 const Options& options) |
25 : name_prefix_(name_prefix), | 18 : name_prefix_(name_prefix), |
26 name_(name_prefix), | 19 name_(name_prefix), |
27 options_(options), | 20 options_(options), |
28 thread_(), | |
29 event_(WaitableEvent::ResetPolicy::MANUAL, | 21 event_(WaitableEvent::ResetPolicy::MANUAL, |
30 WaitableEvent::InitialState::NOT_SIGNALED), | 22 WaitableEvent::InitialState::NOT_SIGNALED) {} |
31 tid_(0), | |
32 joined_(false) {} | |
33 | 23 |
34 SimpleThread::~SimpleThread() { | 24 SimpleThread::~SimpleThread() { |
35 DCHECK(HasBeenStarted()) << "SimpleThread was never started."; | 25 DCHECK(HasBeenStarted()) << "SimpleThread was never started."; |
36 DCHECK(HasBeenJoined()) << "SimpleThread destroyed without being Join()ed."; | 26 DCHECK(!options_.joinable || HasBeenJoined()) |
27 << "Joinable SimpleThread destroyed without being Join()ed."; | |
37 } | 28 } |
38 | 29 |
39 void SimpleThread::Start() { | 30 void SimpleThread::Start() { |
40 DCHECK(!HasBeenStarted()) << "Tried to Start a thread multiple times."; | 31 DCHECK(!HasBeenStarted()) << "Tried to Start a thread multiple times."; |
41 bool success; | 32 bool success = |
42 if (options_.priority() == ThreadPriority::NORMAL) { | 33 options_.joinable |
43 success = PlatformThread::Create(options_.stack_size(), this, &thread_); | 34 ? PlatformThread::CreateWithPriority(options_.stack_size, this, |
44 } else { | 35 &thread_, options_.priority) |
45 success = PlatformThread::CreateWithPriority(options_.stack_size(), this, | 36 : PlatformThread::CreateNonJoinableWithPriority( |
46 &thread_, options_.priority()); | 37 options_.stack_size, this, options_.priority); |
47 } | |
48 DCHECK(success); | 38 DCHECK(success); |
49 base::ThreadRestrictions::ScopedAllowWait allow_wait; | 39 ThreadRestrictions::ScopedAllowWait allow_wait; |
50 event_.Wait(); // Wait for the thread to complete initialization. | 40 event_.Wait(); // Wait for the thread to complete initialization. |
51 } | 41 } |
52 | 42 |
53 void SimpleThread::Join() { | 43 void SimpleThread::Join() { |
44 DCHECK(options_.joinable) << "A non-joinable thread can't be joined."; | |
54 DCHECK(HasBeenStarted()) << "Tried to Join a never-started thread."; | 45 DCHECK(HasBeenStarted()) << "Tried to Join a never-started thread."; |
55 DCHECK(!HasBeenJoined()) << "Tried to Join a thread multiple times."; | 46 DCHECK(!HasBeenJoined()) << "Tried to Join a thread multiple times."; |
56 PlatformThread::Join(thread_); | 47 PlatformThread::Join(thread_); |
48 thread_ = PlatformThreadHandle(); | |
57 joined_ = true; | 49 joined_ = true; |
58 } | 50 } |
59 | 51 |
60 bool SimpleThread::HasBeenStarted() { | 52 bool SimpleThread::HasBeenStarted() { |
61 base::ThreadRestrictions::ScopedAllowWait allow_wait; | 53 ThreadRestrictions::ScopedAllowWait allow_wait; |
62 return event_.IsSignaled(); | 54 return event_.IsSignaled(); |
63 } | 55 } |
64 | 56 |
65 void SimpleThread::ThreadMain() { | 57 void SimpleThread::ThreadMain() { |
66 tid_ = PlatformThread::CurrentId(); | 58 tid_ = PlatformThread::CurrentId(); |
67 // Construct our full name of the form "name_prefix_/TID". | 59 // Construct our full name of the form "name_prefix_/TID". |
68 name_.push_back('/'); | 60 name_.push_back('/'); |
69 name_.append(IntToString(tid_)); | 61 name_.append(IntToString(tid_)); |
70 PlatformThread::SetName(name_); | 62 PlatformThread::SetName(name_); |
71 | 63 |
72 // We've initialized our new thread, signal that we're done to Start(). | 64 // We've initialized our new thread, signal that we're done to Start(). |
73 event_.Signal(); | 65 event_.Signal(); |
74 | 66 |
75 Run(); | 67 Run(); |
76 } | 68 } |
77 | 69 |
70 DelegateSimpleThread::Delegate::Delegate() | |
71 #if DCHECK_IS_ON() | |
72 : active_runners_decremented_(WaitableEvent::ResetPolicy::AUTOMATIC, | |
73 WaitableEvent::InitialState::NOT_SIGNALED) | |
74 #endif | |
75 { | |
76 } | |
77 | |
78 DelegateSimpleThread::Delegate::~Delegate() { | |
79 #if DCHECK_IS_ON() | |
80 // A Delegate is allowed to be destroyed after returning from Run(). This | |
81 // means that destruction can legally occur between the end of Run() and | |
82 // |active_runners_| being decremented in RunHelper(). Allow a minimal | |
83 // reasonable delay for this race to unwind. | |
84 constexpr TimeDelta kMaxCompletionWait = TimeDelta::FromMilliseconds(200); | |
85 TimeDelta remaining_time = kMaxCompletionWait; | |
86 const TimeTicks max_completion_time = TimeTicks::Now() + kMaxCompletionWait; | |
87 do { | |
88 // At least a single Wait() call is required (even when |active_runners_| is | |
89 // already zero) in order to synchronize with the matching Signal() call; | |
90 // otherwise there is a race between it and |active_runners_decremented_|'s | |
91 // destructor (as highlighted by TSAN); hence the do-while. | |
92 ThreadRestrictions::ScopedAllowWait allow_wait; | |
93 active_runners_decremented_.TimedWait(remaining_time); | |
94 remaining_time = max_completion_time - TimeTicks::Now(); | |
95 } while (!AtomicRefCountIsZero(&active_runners_) && | |
96 remaining_time > TimeDelta()); | |
97 | |
98 DCHECK(AtomicRefCountIsZero(&active_runners_)) | |
danakj
2016/08/12 20:49:10
Hm, I guess this is better than nothing? Idk, it's
gab
2016/08/12 21:23:17
Right... I can't think of a way around this. My th
| |
99 << "Delegate cannot be deleted with Run() in progress."; | |
100 #endif // DCHECK_IS_ON() | |
101 } | |
102 | |
103 void DelegateSimpleThread::Delegate::RunHelper() { | |
104 #if DCHECK_IS_ON() | |
105 AtomicRefCountInc(&active_runners_); | |
106 #endif // DCHECK_IS_ON() | |
107 | |
108 Run(); | |
109 | |
danakj
2016/08/12 20:49:09
would it help to DCHECK here that ~Delegate hasn't
gab
2016/08/12 21:23:17
It's correct for a Delegate to say "DeleteSoon(thi
| |
110 #if DCHECK_IS_ON() | |
111 AtomicRefCountDec(&active_runners_); | |
112 active_runners_decremented_.Signal(); | |
113 #endif // DCHECK_IS_ON() | |
114 } | |
115 | |
78 DelegateSimpleThread::DelegateSimpleThread(Delegate* delegate, | 116 DelegateSimpleThread::DelegateSimpleThread(Delegate* delegate, |
79 const std::string& name_prefix) | 117 const std::string& name_prefix) |
80 : SimpleThread(name_prefix), | 118 : DelegateSimpleThread(delegate, name_prefix, Options()) {} |
81 delegate_(delegate) { | |
82 } | |
83 | 119 |
84 DelegateSimpleThread::DelegateSimpleThread(Delegate* delegate, | 120 DelegateSimpleThread::DelegateSimpleThread(Delegate* delegate, |
85 const std::string& name_prefix, | 121 const std::string& name_prefix, |
86 const Options& options) | 122 const Options& options) |
87 : SimpleThread(name_prefix, options), | 123 : SimpleThread(name_prefix, options), |
88 delegate_(delegate) { | 124 delegate_(delegate) { |
125 DCHECK(delegate_); | |
89 } | 126 } |
90 | 127 |
91 DelegateSimpleThread::~DelegateSimpleThread() { | 128 DelegateSimpleThread::~DelegateSimpleThread() = default; |
92 } | |
93 | 129 |
94 void DelegateSimpleThread::Run() { | 130 void DelegateSimpleThread::Run() { |
95 DCHECK(delegate_) << "Tried to call Run without a delegate (called twice?)"; | 131 #if DCHECK_IS_ON() |
96 delegate_->Run(); | 132 // |ran_| must be verified and updated before calling RunHelper() as non- |
97 delegate_ = NULL; | 133 // joinable DelegateSimpleThread can be deleted before it returns. |
134 DCHECK(!ran_) << "Ran twice?"; | |
135 ran_ = true; | |
136 #endif // DCHECK_IS_ON() | |
137 | |
138 delegate_->RunHelper(); | |
98 } | 139 } |
99 | 140 |
100 DelegateSimpleThreadPool::DelegateSimpleThreadPool( | 141 DelegateSimpleThreadPool::DelegateSimpleThreadPool( |
101 const std::string& name_prefix, | 142 const std::string& name_prefix, |
102 int num_threads) | 143 int num_threads) |
103 : name_prefix_(name_prefix), | 144 : name_prefix_(name_prefix), |
104 num_threads_(num_threads), | 145 num_threads_(num_threads), |
105 dry_(WaitableEvent::ResetPolicy::MANUAL, | 146 dry_(WaitableEvent::ResetPolicy::MANUAL, |
106 WaitableEvent::InitialState::NOT_SIGNALED) {} | 147 WaitableEvent::InitialState::NOT_SIGNALED) {} |
107 | 148 |
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160 | 201 |
161 // Signal to any other threads that we're currently out of work. | 202 // Signal to any other threads that we're currently out of work. |
162 if (delegates_.empty()) | 203 if (delegates_.empty()) |
163 dry_.Reset(); | 204 dry_.Reset(); |
164 } | 205 } |
165 | 206 |
166 // A NULL delegate pointer signals us to quit. | 207 // A NULL delegate pointer signals us to quit. |
167 if (!work) | 208 if (!work) |
168 break; | 209 break; |
169 | 210 |
170 work->Run(); | 211 work->RunHelper(); |
171 } | 212 } |
172 } | 213 } |
173 | 214 |
174 } // namespace base | 215 } // namespace base |
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