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// Copyright 2012 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "components/prefs/pref_notifier_impl.h"
#include "base/debug/alias.h"
#include "base/debug/dump_without_crashing.h"
#include "base/logging.h"
#include "base/memory/ptr_util.h"
#include "base/observer_list.h"
#include "base/strings/strcat.h"
#include "components/prefs/pref_service.h"
PrefNotifierImpl::PrefNotifierImpl() : pref_service_(nullptr) {}
PrefNotifierImpl::PrefNotifierImpl(PrefService* service)
: pref_service_(service) {
}
PrefNotifierImpl::~PrefNotifierImpl() {
DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
// Verify that there are no pref observers when we shut down.
for (const auto& observer_list : pref_observers_) {
if (observer_list.second->begin() != observer_list.second->end()) {
// Generally, there should not be any subscribers left when the profile
// is destroyed because a) those may indicate that the subscriber class
// maintains an active pointer to the profile that might be used for
// accessing a destroyed profile and b) those subscribers will try to
// unsubscribe from a PrefService that has been destroyed with the
// profile.
// There is one exception that is safe: Static objects that are leaked
// on process termination, if these objects just subscribe to preferences
// and never access the profile after destruction. As these objects are
// leaked on termination, it is guaranteed that they don't attempt to
// unsubscribe.
const auto& pref_name = observer_list.first;
std::string message = base::StrCat(
{"Pref observer for ", pref_name, " found at shutdown."});
LOG(WARNING) << message;
DEBUG_ALIAS_FOR_CSTR(aliased_message, message.c_str(), 128);
// TODO(crbug.com/942491, 946668, 945772) The following code collects
// stacktraces that show how the profile is destroyed that owns
// preferences which are known to have subscriptions outliving the
// profile.
if (
// For DbusAppmenu, crbug.com/946668
pref_name == "bookmark_bar.show_on_all_tabs" ||
// For BrowserWindowPropertyManager, crbug.com/942491
pref_name == "profile.icon_version") {
base::debug::DumpWithoutCrashing();
}
}
}
// Same for initialization observers.
if (!init_observers_.empty())
LOG(WARNING) << "Init observer found at shutdown.";
pref_observers_.clear();
init_observers_.clear();
}
void PrefNotifierImpl::AddPrefObserver(const std::string& path,
PrefObserver* obs) {
DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
// Get the pref observer list associated with the path.
auto observer_iterator = pref_observers_.find(path);
if (observer_iterator == pref_observers_.end()) {
observer_iterator =
pref_observers_.emplace(path, std::make_unique<PrefObserverList>())
.first;
}
PrefObserverList* observer_list = observer_iterator->second.get();
// Add the pref observer. ObserverList will DCHECK if it already is
// in the list.
observer_list->AddObserver(obs);
}
void PrefNotifierImpl::RemovePrefObserver(const std::string& path,
PrefObserver* obs) {
DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
auto observer_iterator = pref_observers_.find(path);
if (observer_iterator == pref_observers_.end()) {
return;
}
PrefObserverList* observer_list = observer_iterator->second.get();
observer_list->RemoveObserver(obs);
}
void PrefNotifierImpl::AddPrefObserverAllPrefs(PrefObserver* observer) {
DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
all_prefs_pref_observers_.AddObserver(observer);
}
void PrefNotifierImpl::RemovePrefObserverAllPrefs(PrefObserver* observer) {
DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
all_prefs_pref_observers_.RemoveObserver(observer);
}
void PrefNotifierImpl::AddInitObserver(base::OnceCallback<void(bool)> obs) {
init_observers_.push_back(std::move(obs));
}
void PrefNotifierImpl::OnPreferenceChanged(const std::string& path) {
FireObservers(path);
}
void PrefNotifierImpl::OnInitializationCompleted(bool succeeded) {
DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
// We must move init_observers_ to a local variable before we run
// observers, or we can end up in this method re-entrantly before
// clearing the observers list.
PrefInitObserverList observers;
std::swap(observers, init_observers_);
for (auto& observer : observers)
std::move(observer).Run(succeeded);
}
void PrefNotifierImpl::FireObservers(const std::string& path) {
DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
// Only send notifications for registered preferences.
if (!pref_service_->FindPreference(path))
return;
// Fire observers for any preference change.
for (auto& observer : all_prefs_pref_observers_)
observer.OnPreferenceChanged(pref_service_, path);
auto observer_iterator = pref_observers_.find(path);
if (observer_iterator == pref_observers_.end())
return;
for (PrefObserver& observer : *(observer_iterator->second))
observer.OnPreferenceChanged(pref_service_, path);
}
void PrefNotifierImpl::SetPrefService(PrefService* pref_service) {
DCHECK(pref_service_ == nullptr);
pref_service_ = pref_service;
}
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