Files
Guogang Li 9ea2c9fd8e Fixed the data race in ObserverList
PiperOrigin-RevId: 528638464
2023-05-01 19:11:52 -07:00

80 lines
2.2 KiB
C++

// Copyright 2021 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#ifndef THIRD_PARTY_NEARBY_INTERNAL_BASE_OBSERVER_LIST_H_
#define THIRD_PARTY_NEARBY_INTERNAL_BASE_OBSERVER_LIST_H_
#include "absl/base/thread_annotations.h"
#include "absl/container/flat_hash_set.h"
#include "internal/platform/mutex_lock.h"
namespace nearby {
template <class ObserverType>
class ObserverList {
public:
using iterator = typename absl::flat_hash_set<ObserverType*>::iterator;
using const_iterator =
typename absl::flat_hash_set<ObserverType*>::const_iterator;
~ObserverList() ABSL_LOCKS_EXCLUDED(mutex_) {
MutexLock lock(&mutex_);
observers_.clear();
}
void AddObserver(ObserverType* observer) ABSL_LOCKS_EXCLUDED(mutex_) {
MutexLock lock(&mutex_);
observers_.insert(observer);
}
void RemoveObserver(ObserverType* observer) ABSL_LOCKS_EXCLUDED(mutex_) {
MutexLock lock(&mutex_);
observers_.erase(observer);
}
bool HasObserver(ObserverType* observer) ABSL_LOCKS_EXCLUDED(mutex_) {
MutexLock lock(&mutex_);
return observers_.contains(observer);
}
void Clear() ABSL_LOCKS_EXCLUDED(mutex_) {
MutexLock lock(&mutex_);
observers_.clear();
}
bool empty() const ABSL_LOCKS_EXCLUDED(mutex_) {
MutexLock lock(&mutex_);
return observers_.empty();
}
int size() const ABSL_LOCKS_EXCLUDED(mutex_) {
MutexLock lock(&mutex_);
return observers_.size();
}
absl::flat_hash_set<ObserverType*> GetObservers()
ABSL_LOCKS_EXCLUDED(mutex_) {
MutexLock lock(&mutex_);
return observers_;
}
private:
mutable Mutex mutex_;
absl::flat_hash_set<ObserverType*> observers_ ABSL_GUARDED_BY(mutex_);
};
} // namespace nearby
#endif // THIRD_PARTY_NEARBY_INTERNAL_BASE_OBSERVER_LIST_H_