// 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 CHROME_BROWSER_PREFS_PREF_MODEL_ASSOCIATOR_H_
#define CHROME_BROWSER_PREFS_PREF_MODEL_ASSOCIATOR_H_
#include <map>
#include <set>
#include <string>
#include "base/basictypes.h"
#include "base/compiler_specific.h"
#include "base/containers/hash_tables.h"
#include "base/gtest_prod_util.h"
#include "base/observer_list.h"
#include "base/threading/non_thread_safe.h"
#include "chrome/browser/prefs/synced_pref_observer.h"
#include "sync/api/sync_data.h"
#include "sync/api/syncable_service.h"
class PrefRegistrySyncable;
class PrefServiceSyncable;
namespace sync_pb {
class PreferenceSpecifics;
}
namespace base {
class Value;
}
// Contains all preference sync related logic.
// TODO(sync): Merge this into PrefService once we separate the profile
// PrefService from the local state PrefService.
class PrefModelAssociator
: public syncer::SyncableService,
public base::NonThreadSafe {
public:
explicit PrefModelAssociator(syncer::ModelType type);
virtual ~PrefModelAssociator();
// See description above field for details.
bool models_associated() const { return models_associated_; }
// syncer::SyncableService implementation.
virtual syncer::SyncDataList GetAllSyncData(
syncer::ModelType type) const OVERRIDE;
virtual syncer::SyncError ProcessSyncChanges(
const tracked_objects::Location& from_here,
const syncer::SyncChangeList& change_list) OVERRIDE;
virtual syncer::SyncMergeResult MergeDataAndStartSyncing(
syncer::ModelType type,
const syncer::SyncDataList& initial_sync_data,
scoped_ptr<syncer::SyncChangeProcessor> sync_processor,
scoped_ptr<syncer::SyncErrorFactory> sync_error_factory) OVERRIDE;
virtual void StopSyncing(syncer::ModelType type) OVERRIDE;
// Returns the list of preference names that are registered as syncable, and
// hence should be monitored for changes.
std::set<std::string> registered_preferences() const;
// Register a preference with the specified name for syncing. We do not care
// about the type at registration time, but when changes arrive from the
// syncer, we check if they can be applied and if not drop them.
// Note: This should only be called at profile startup time (before sync
// begins).
virtual void RegisterPref(const char* name);
// Returns true if the specified preference is registered for syncing.
virtual bool IsPrefRegistered(const char* name);
// Process a local preference change. This can trigger new SyncChanges being
// sent to the syncer.
virtual void ProcessPrefChange(const std::string& name);
void SetPrefService(PrefServiceSyncable* pref_service);
// Merges the local_value into the supplied server_value and returns
// the result (caller takes ownership). If there is a conflict, the server
// value always takes precedence. Note that only certain preferences will
// actually be merged, all others will return a copy of the server value. See
// the method's implementation for details.
static scoped_ptr<base::Value> MergePreference(
const std::string& name,
const base::Value& local_value,
const base::Value& server_value);
// Fills |sync_data| with a sync representation of the preference data
// provided.
bool CreatePrefSyncData(const std::string& name,
const base::Value& value,
syncer::SyncData* sync_data) const;
// Extract preference value and name from sync specifics.
base::Value* ReadPreferenceSpecifics(
const sync_pb::PreferenceSpecifics& specifics,
std::string* name);
// Returns true if the pref under the given name is pulled down from sync.
// Note this does not refer to SYNCABLE_PREF.
bool IsPrefSynced(const std::string& name) const;
// Adds a SyncedPrefObserver to watch for changes to a specific pref.
void AddSyncedPrefObserver(const std::string& name,
SyncedPrefObserver* observer);
// Removes a SyncedPrefObserver from a pref's list of observers.
void RemoveSyncedPrefObserver(const std::string& name,
SyncedPrefObserver* observer);
protected:
friend class ProfileSyncServicePreferenceTest;
typedef std::map<std::string, syncer::SyncData> SyncDataMap;
// Create an association for a given preference. If |sync_pref| is valid,
// signifying that sync has data for this preference, we reconcile their data
// with ours and append a new UPDATE SyncChange to |sync_changes|. If
// sync_pref is not set, we append an ADD SyncChange to |sync_changes| with
// the current preference data.
// |migrated_preference_list| points to a vector that may be updated with a
// string containing the old name of the preference described by |pref_name|.
// Note: We do not modify the sync data for preferences that are either
// controlled by policy (are not user modifiable) or have their default value
// (are not user controlled).
void InitPrefAndAssociate(const syncer::SyncData& sync_pref,
const std::string& pref_name,
syncer::SyncChangeList* sync_changes,
SyncDataMap* migrated_preference_list);
static base::Value* MergeListValues(
const base::Value& from_value, const base::Value& to_value);
static base::Value* MergeDictionaryValues(const base::Value& from_value,
const base::Value& to_value);
// Returns whether a given preference name is a new name of a migrated
// preference. Exposed here for testing.
static bool IsMigratedPreference(const char* preference_name);
static bool IsOldMigratedPreference(const char* old_preference_name);
// Do we have an active association between the preferences and sync models?
// Set when start syncing, reset in StopSyncing. While this is not set, we
// ignore any local preference changes (when we start syncing we will look
// up the most recent values anyways).
bool models_associated_;
// Whether we're currently processing changes from the syncer. While this is
// true, we ignore any local preference changes, since we triggered them.
bool processing_syncer_changes_;
// A set of preference names.
typedef std::set<std::string> PreferenceSet;
// All preferences that have registered as being syncable with this profile.
PreferenceSet registered_preferences_;
// The preferences that are currently synced (excludes those preferences
// that have never had sync data and currently have default values or are
// policy controlled).
// Note: this set never decreases, only grows to eventually match
// registered_preferences_ as more preferences are synced. It determines
// whether a preference change should update an existing sync node or create
// a new sync node.
PreferenceSet synced_preferences_;
// The PrefService we are syncing to.
PrefServiceSyncable* pref_service_;
// Sync's syncer::SyncChange handler. We push all our changes through this.
scoped_ptr<syncer::SyncChangeProcessor> sync_processor_;
// Sync's error handler. We use this to create sync errors.
scoped_ptr<syncer::SyncErrorFactory> sync_error_factory_;
// The datatype that this associator is responible for, either PREFERENCES or
// PRIORITY_PREFERENCES.
syncer::ModelType type_;
private:
// Map prefs to lists of observers. Observers will receive notification when
// a pref changes, including the detail of whether or not the change came
// from sync.
typedef ObserverList<SyncedPrefObserver> SyncedPrefObserverList;
typedef base::hash_map<std::string, SyncedPrefObserverList*>
SyncedPrefObserverMap;
void NotifySyncedPrefObservers(const std::string& path, bool from_sync) const;
SyncedPrefObserverMap synced_pref_observers_;
DISALLOW_COPY_AND_ASSIGN(PrefModelAssociator);
};
#endif // CHROME_BROWSER_PREFS_PREF_MODEL_ASSOCIATOR_H_