mirror of
https://github.com/DrKLO/Telegram.git
synced 2024-12-23 15:00:50 +01:00
87 lines
2.4 KiB
C++
87 lines
2.4 KiB
C++
// Copyright (c) 2012 The Chromium Authors. All rights reserved.
|
|
// Use of this source code is governed by a BSD-style license that can be
|
|
// found in the LICENSE file.
|
|
|
|
#ifndef BASE_SCOPED_OBSERVER_H_
|
|
#define BASE_SCOPED_OBSERVER_H_
|
|
|
|
#include <stddef.h>
|
|
|
|
#include <algorithm>
|
|
#include <vector>
|
|
|
|
#include "base/logging.h"
|
|
#include "base/macros.h"
|
|
#include "base/stl_util.h"
|
|
|
|
// ScopedObserver is used to keep track of the set of sources an object has
|
|
// attached itself to as an observer. When ScopedObserver is destroyed it
|
|
// removes the object as an observer from all sources it has been added to.
|
|
// Basic example (as a member variable):
|
|
//
|
|
// class MyFooObserver : public FooObserver {
|
|
// ...
|
|
// private:
|
|
// ScopedObserver<Foo, FooObserver> observed_foo_{this};
|
|
// };
|
|
//
|
|
// For cases with methods not named AddObserver/RemoveObserver:
|
|
//
|
|
// class MyFooStateObserver : public FooStateObserver {
|
|
// ...
|
|
// private:
|
|
// ScopedObserver<Foo,
|
|
// FooStateObserver,
|
|
// &Foo::AddStateObserver,
|
|
// &Foo::RemoveStateObserver>
|
|
// observed_foo_{this};
|
|
// };
|
|
template <class Source,
|
|
class Observer,
|
|
void (Source::*AddObsFn)(Observer*) = &Source::AddObserver,
|
|
void (Source::*RemoveObsFn)(Observer*) = &Source::RemoveObserver>
|
|
class ScopedObserver {
|
|
public:
|
|
explicit ScopedObserver(Observer* observer) : observer_(observer) {}
|
|
|
|
~ScopedObserver() {
|
|
RemoveAll();
|
|
}
|
|
|
|
// Adds the object passed to the constructor as an observer on |source|.
|
|
void Add(Source* source) {
|
|
sources_.push_back(source);
|
|
(source->*AddObsFn)(observer_);
|
|
}
|
|
|
|
// Remove the object passed to the constructor as an observer from |source|.
|
|
void Remove(Source* source) {
|
|
auto it = std::find(sources_.begin(), sources_.end(), source);
|
|
DCHECK(it != sources_.end());
|
|
sources_.erase(it);
|
|
(source->*RemoveObsFn)(observer_);
|
|
}
|
|
|
|
void RemoveAll() {
|
|
for (size_t i = 0; i < sources_.size(); ++i)
|
|
(sources_[i]->*RemoveObsFn)(observer_);
|
|
sources_.clear();
|
|
}
|
|
|
|
bool IsObserving(Source* source) const {
|
|
return base::Contains(sources_, source);
|
|
}
|
|
|
|
bool IsObservingSources() const { return !sources_.empty(); }
|
|
|
|
size_t GetSourcesCount() const { return sources_.size(); }
|
|
|
|
private:
|
|
Observer* observer_;
|
|
|
|
std::vector<Source*> sources_;
|
|
|
|
DISALLOW_COPY_AND_ASSIGN(ScopedObserver);
|
|
};
|
|
|
|
#endif // BASE_SCOPED_OBSERVER_H_
|