1 // Copyright 2017 The Abseil Authors.
2 //
3 // Licensed under the Apache License, Version 2.0 (the "License");
4 // you may not use this file except in compliance with the License.
5 // You may obtain a copy of the License at
6 //
7 // https://www.apache.org/licenses/LICENSE-2.0
8 //
9 // Unless required by applicable law or agreed to in writing, software
10 // distributed under the License is distributed on an "AS IS" BASIS,
11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 // See the License for the specific language governing permissions and
13 // limitations under the License.
14
15 #include "absl/synchronization/notification.h"
16
17 #include <atomic>
18
19 #include "absl/base/internal/raw_logging.h"
20 #include "absl/synchronization/mutex.h"
21 #include "absl/time/time.h"
22
23 namespace absl {
24 ABSL_NAMESPACE_BEGIN
25
Notify()26 void Notification::Notify() {
27 MutexLock l(&this->mutex_);
28
29 #ifndef NDEBUG
30 if (ABSL_PREDICT_FALSE(notified_yet_.load(std::memory_order_relaxed))) {
31 ABSL_RAW_LOG(
32 FATAL,
33 "Notify() method called more than once for Notification object %p",
34 static_cast<void *>(this));
35 }
36 #endif
37
38 notified_yet_.store(true, std::memory_order_release);
39 }
40
~Notification()41 Notification::~Notification() {
42 // Make sure that the thread running Notify() exits before the object is
43 // destructed.
44 MutexLock l(&this->mutex_);
45 }
46
WaitForNotification() const47 void Notification::WaitForNotification() const {
48 if (!HasBeenNotifiedInternal(&this->notified_yet_)) {
49 this->mutex_.LockWhen(Condition(&HasBeenNotifiedInternal,
50 &this->notified_yet_));
51 this->mutex_.Unlock();
52 }
53 }
54
WaitForNotificationWithTimeout(absl::Duration timeout) const55 bool Notification::WaitForNotificationWithTimeout(
56 absl::Duration timeout) const {
57 bool notified = HasBeenNotifiedInternal(&this->notified_yet_);
58 if (!notified) {
59 notified = this->mutex_.LockWhenWithTimeout(
60 Condition(&HasBeenNotifiedInternal, &this->notified_yet_), timeout);
61 this->mutex_.Unlock();
62 }
63 return notified;
64 }
65
WaitForNotificationWithDeadline(absl::Time deadline) const66 bool Notification::WaitForNotificationWithDeadline(absl::Time deadline) const {
67 bool notified = HasBeenNotifiedInternal(&this->notified_yet_);
68 if (!notified) {
69 notified = this->mutex_.LockWhenWithDeadline(
70 Condition(&HasBeenNotifiedInternal, &this->notified_yet_), deadline);
71 this->mutex_.Unlock();
72 }
73 return notified;
74 }
75
76 ABSL_NAMESPACE_END
77 } // namespace absl
78