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/*
* Copyright 2011 The WebRTC project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#ifndef API_NOTIFIER_H_
#define API_NOTIFIER_H_
#include <list>
#include "api/media_stream_interface.h"
#include "api/sequence_checker.h"
#include "rtc_base/checks.h"
#include "rtc_base/system/no_unique_address.h"
namespace webrtc {
// Implements a template version of a notifier.
// TODO(deadbeef): This is an implementation detail; move out of api/.
template <class T>
class Notifier : public T {
public:
Notifier() = default;
virtual void RegisterObserver(ObserverInterface* observer) {
RTC_DCHECK_RUN_ON(&sequence_checker_);
RTC_DCHECK(observer != nullptr);
observers_.push_back(observer);
}
virtual void UnregisterObserver(ObserverInterface* observer) {
RTC_DCHECK_RUN_ON(&sequence_checker_);
for (std::list<ObserverInterface*>::iterator it = observers_.begin();
it != observers_.end(); it++) {
if (*it == observer) {
observers_.erase(it);
break;
}
}
}
void FireOnChanged() {
RTC_DCHECK_RUN_ON(&sequence_checker_);
// Copy the list of observers to avoid a crash if the observer object
// unregisters as a result of the OnChanged() call. If the same list is used
// UnregisterObserver will affect the list make the iterator invalid.
std::list<ObserverInterface*> observers = observers_;
for (std::list<ObserverInterface*>::iterator it = observers.begin();
it != observers.end(); ++it) {
(*it)->OnChanged();
}
}
protected:
std::list<ObserverInterface*> observers_ RTC_GUARDED_BY(sequence_checker_);
private:
RTC_NO_UNIQUE_ADDRESS SequenceChecker sequence_checker_{
SequenceChecker::kDetached};
};
} // namespace webrtc
#endif // API_NOTIFIER_H_