1 // Copyright 2010 The Chromium Authors
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4
5 #include "components/prefs/pref_change_registrar.h"
6
7 #include <ostream>
8
9 #include "base/check.h"
10 #include "base/functional/bind.h"
11 #include "base/notreached.h"
12 #include "components/prefs/pref_service.h"
13
PrefChangeRegistrar()14 PrefChangeRegistrar::PrefChangeRegistrar() : service_(nullptr) {}
15
~PrefChangeRegistrar()16 PrefChangeRegistrar::~PrefChangeRegistrar() {
17 // If you see an invalid memory access in this destructor, this
18 // PrefChangeRegistrar might be subscribed to an OffTheRecordProfileImpl that
19 // has been destroyed. This should not happen any more but be warned.
20 // Feel free to contact battre@chromium.org in case this happens.
21 //
22 // This can also happen for non-OTR profiles, when the
23 // DestroyProfileOnBrowserClose flag is enabled. In that case, contact
24 // nicolaso@chromium.org.
25 RemoveAll();
26 }
27
Init(PrefService * service)28 void PrefChangeRegistrar::Init(PrefService* service) {
29 DCHECK(IsEmpty() || service_ == service);
30 service_ = service;
31 }
32
Reset()33 void PrefChangeRegistrar::Reset() {
34 RemoveAll();
35 service_ = nullptr;
36 }
37
Add(std::string_view path,const base::RepeatingClosure & obs)38 void PrefChangeRegistrar::Add(std::string_view path,
39 const base::RepeatingClosure& obs) {
40 Add(path,
41 base::BindRepeating(&PrefChangeRegistrar::InvokeUnnamedCallback, obs));
42 }
43
Add(std::string_view path,const NamedChangeCallback & obs)44 void PrefChangeRegistrar::Add(std::string_view path,
45 const NamedChangeCallback& obs) {
46 if (!service_) {
47 NOTREACHED();
48 }
49 DCHECK(!IsObserved(path)) << "Already had pref, \"" << path
50 << "\", registered.";
51
52 service_->AddPrefObserver(path, this);
53 observers_.insert_or_assign(std::string(path), obs);
54 }
55
Remove(std::string_view path)56 void PrefChangeRegistrar::Remove(std::string_view path) {
57 DCHECK(IsObserved(path));
58
59 // Use std::map::erase directly once C++23 is supported.
60 auto it = observers_.find(path);
61 observers_.erase(it);
62 service_->RemovePrefObserver(path, this);
63 }
64
RemoveAll()65 void PrefChangeRegistrar::RemoveAll() {
66 for (ObserverMap::const_iterator it = observers_.begin();
67 it != observers_.end(); ++it) {
68 service_->RemovePrefObserver(it->first, this);
69 }
70
71 observers_.clear();
72 }
73
IsEmpty() const74 bool PrefChangeRegistrar::IsEmpty() const {
75 return observers_.empty();
76 }
77
IsObserved(std::string_view pref)78 bool PrefChangeRegistrar::IsObserved(std::string_view pref) {
79 return observers_.find(pref) != observers_.end();
80 }
81
OnPreferenceChanged(PrefService * service,std::string_view pref)82 void PrefChangeRegistrar::OnPreferenceChanged(PrefService* service,
83 std::string_view pref) {
84 if (auto it = observers_.find(pref); it != observers_.end()) {
85 // TODO: crbug.com/349741884 - Consider changing the callback to accept a
86 // string_view.
87 it->second.Run(std::string(pref));
88 }
89 }
90
InvokeUnnamedCallback(const base::RepeatingClosure & callback,const std::string & pref_name)91 void PrefChangeRegistrar::InvokeUnnamedCallback(
92 const base::RepeatingClosure& callback,
93 const std::string& pref_name) {
94 callback.Run();
95 }
96
prefs()97 PrefService* PrefChangeRegistrar::prefs() {
98 return service_;
99 }
100
prefs() const101 const PrefService* PrefChangeRegistrar::prefs() const {
102 return service_;
103 }
104