// 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.

#include "base/prefs/pref_notifier_impl.h"

#include "base/logging.h"
#include "base/prefs/pref_service.h"
#include "base/stl_util.h"

PrefNotifierImpl::PrefNotifierImpl()
    : pref_service_(NULL) {
}

PrefNotifierImpl::PrefNotifierImpl(PrefService* service)
    : pref_service_(service) {
}

PrefNotifierImpl::~PrefNotifierImpl() {
  DCHECK(thread_checker_.CalledOnValidThread());

  // Verify that there are no pref observers when we shut down.
  for (PrefObserverMap::iterator it = pref_observers_.begin();
       it != pref_observers_.end(); ++it) {
    PrefObserverList::Iterator obs_iterator(it->second);
    if (obs_iterator.GetNext()) {
      LOG(WARNING) << "pref observer found at shutdown " << it->first;
    }
  }

  // Same for initialization observers.
  if (!init_observers_.empty())
    LOG(WARNING) << "Init observer found at shutdown.";

  STLDeleteContainerPairSecondPointers(pref_observers_.begin(),
                                       pref_observers_.end());
  pref_observers_.clear();
  init_observers_.clear();
}

void PrefNotifierImpl::AddPrefObserver(const std::string& path,
                                       PrefObserver* obs) {
  // Get the pref observer list associated with the path.
  PrefObserverList* observer_list = NULL;
  const PrefObserverMap::iterator observer_iterator =
      pref_observers_.find(path);
  if (observer_iterator == pref_observers_.end()) {
    observer_list = new PrefObserverList;
    pref_observers_[path] = observer_list;
  } else {
    observer_list = observer_iterator->second;
  }

  // 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(thread_checker_.CalledOnValidThread());

  const PrefObserverMap::iterator observer_iterator =
      pref_observers_.find(path);
  if (observer_iterator == pref_observers_.end()) {
    return;
  }

  PrefObserverList* observer_list = observer_iterator->second;
  observer_list->RemoveObserver(obs);
}

void PrefNotifierImpl::AddInitObserver(base::Callback<void(bool)> obs) {
  init_observers_.push_back(obs);
}

void PrefNotifierImpl::OnPreferenceChanged(const std::string& path) {
  FireObservers(path);
}

void PrefNotifierImpl::OnInitializationCompleted(bool succeeded) {
  DCHECK(thread_checker_.CalledOnValidThread());

  // We must make a copy of init_observers_ and clear it before we run
  // observers, or we can end up in this method re-entrantly before
  // clearing the observers list.
  PrefInitObserverList observers(init_observers_);
  init_observers_.clear();

  for (PrefInitObserverList::iterator it = observers.begin();
       it != observers.end();
       ++it) {
    it->Run(succeeded);
  }
}

void PrefNotifierImpl::FireObservers(const std::string& path) {
  DCHECK(thread_checker_.CalledOnValidThread());

  // Only send notifications for registered preferences.
  if (!pref_service_->FindPreference(path))
    return;

  const PrefObserverMap::iterator observer_iterator =
      pref_observers_.find(path);
  if (observer_iterator == pref_observers_.end())
    return;

  FOR_EACH_OBSERVER(PrefObserver,
                    *(observer_iterator->second),
                    OnPreferenceChanged(pref_service_, path));
}

void PrefNotifierImpl::SetPrefService(PrefService* pref_service) {
  DCHECK(pref_service_ == NULL);
  pref_service_ = pref_service;
}