blob: 636873581794d69fe411f2d888ec5838356ee758 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
|
// 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 <vector>
#include "base/check.h"
#include "base/ranges/algorithm.h"
#include "base/stl_util.h"
// This class is DEPRECATED. Instead please use one of:
// - base::ScopedObservation for observing a single source.
// - base::ScopedMultiSourceObservation for observing multiple sources.
//
// 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(const ScopedObserver&) = delete;
ScopedObserver& operator=(const ScopedObserver&) = delete;
~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 = base::ranges::find(sources_, 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_;
};
#endif // BASE_SCOPED_OBSERVER_H_
|
