1 // Copyright (c) 2012 The Chromium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #ifndef CHROME_BROWSER_PREFS_PREF_MODEL_ASSOCIATOR_H_ 6 #define CHROME_BROWSER_PREFS_PREF_MODEL_ASSOCIATOR_H_ 7 8 #include <map> 9 #include <set> 10 #include <string> 11 12 #include "base/basictypes.h" 13 #include "base/compiler_specific.h" 14 #include "base/containers/hash_tables.h" 15 #include "base/gtest_prod_util.h" 16 #include "base/observer_list.h" 17 #include "base/threading/non_thread_safe.h" 18 #include "chrome/browser/prefs/synced_pref_observer.h" 19 #include "sync/api/sync_data.h" 20 #include "sync/api/syncable_service.h" 21 22 class PrefRegistrySyncable; 23 class PrefServiceSyncable; 24 25 namespace sync_pb { 26 class PreferenceSpecifics; 27 } 28 29 namespace base { 30 class Value; 31 } 32 33 // Contains all preference sync related logic. 34 // TODO(sync): Merge this into PrefService once we separate the profile 35 // PrefService from the local state PrefService. 36 class PrefModelAssociator 37 : public syncer::SyncableService, 38 public base::NonThreadSafe { 39 public: 40 explicit PrefModelAssociator(syncer::ModelType type); 41 virtual ~PrefModelAssociator(); 42 43 // See description above field for details. models_associated()44 bool models_associated() const { return models_associated_; } 45 46 // syncer::SyncableService implementation. 47 virtual syncer::SyncDataList GetAllSyncData( 48 syncer::ModelType type) const OVERRIDE; 49 virtual syncer::SyncError ProcessSyncChanges( 50 const tracked_objects::Location& from_here, 51 const syncer::SyncChangeList& change_list) OVERRIDE; 52 virtual syncer::SyncMergeResult MergeDataAndStartSyncing( 53 syncer::ModelType type, 54 const syncer::SyncDataList& initial_sync_data, 55 scoped_ptr<syncer::SyncChangeProcessor> sync_processor, 56 scoped_ptr<syncer::SyncErrorFactory> sync_error_factory) OVERRIDE; 57 virtual void StopSyncing(syncer::ModelType type) OVERRIDE; 58 59 // Returns the list of preference names that are registered as syncable, and 60 // hence should be monitored for changes. 61 std::set<std::string> registered_preferences() const; 62 63 // Register a preference with the specified name for syncing. We do not care 64 // about the type at registration time, but when changes arrive from the 65 // syncer, we check if they can be applied and if not drop them. 66 // Note: This should only be called at profile startup time (before sync 67 // begins). 68 virtual void RegisterPref(const char* name); 69 70 // Returns true if the specified preference is registered for syncing. 71 virtual bool IsPrefRegistered(const char* name); 72 73 // Process a local preference change. This can trigger new SyncChanges being 74 // sent to the syncer. 75 virtual void ProcessPrefChange(const std::string& name); 76 77 void SetPrefService(PrefServiceSyncable* pref_service); 78 79 // Merges the local_value into the supplied server_value and returns 80 // the result (caller takes ownership). If there is a conflict, the server 81 // value always takes precedence. Note that only certain preferences will 82 // actually be merged, all others will return a copy of the server value. See 83 // the method's implementation for details. 84 static scoped_ptr<base::Value> MergePreference( 85 const std::string& name, 86 const base::Value& local_value, 87 const base::Value& server_value); 88 89 // Fills |sync_data| with a sync representation of the preference data 90 // provided. 91 bool CreatePrefSyncData(const std::string& name, 92 const base::Value& value, 93 syncer::SyncData* sync_data) const; 94 95 // Extract preference value from sync specifics. 96 base::Value* ReadPreferenceSpecifics( 97 const sync_pb::PreferenceSpecifics& specifics); 98 99 // Returns true if the pref under the given name is pulled down from sync. 100 // Note this does not refer to SYNCABLE_PREF. 101 bool IsPrefSynced(const std::string& name) const; 102 103 // Adds a SyncedPrefObserver to watch for changes to a specific pref. 104 void AddSyncedPrefObserver(const std::string& name, 105 SyncedPrefObserver* observer); 106 107 // Removes a SyncedPrefObserver from a pref's list of observers. 108 void RemoveSyncedPrefObserver(const std::string& name, 109 SyncedPrefObserver* observer); 110 111 protected: 112 friend class PrefsSyncableServiceTest; 113 114 typedef std::map<std::string, syncer::SyncData> SyncDataMap; 115 116 // Create an association for a given preference. If |sync_pref| is valid, 117 // signifying that sync has data for this preference, we reconcile their data 118 // with ours and append a new UPDATE SyncChange to |sync_changes|. If 119 // sync_pref is not set, we append an ADD SyncChange to |sync_changes| with 120 // the current preference data. 121 // |migrated_preference_list| points to a vector that may be updated with a 122 // string containing the old name of the preference described by |pref_name|. 123 // Note: We do not modify the sync data for preferences that are either 124 // controlled by policy (are not user modifiable) or have their default value 125 // (are not user controlled). 126 void InitPrefAndAssociate(const syncer::SyncData& sync_pref, 127 const std::string& pref_name, 128 syncer::SyncChangeList* sync_changes, 129 SyncDataMap* migrated_preference_list); 130 131 static base::Value* MergeListValues( 132 const base::Value& from_value, const base::Value& to_value); 133 static base::Value* MergeDictionaryValues(const base::Value& from_value, 134 const base::Value& to_value); 135 136 // Returns whether a given preference name is a new name of a migrated 137 // preference. Exposed here for testing. 138 static bool IsMigratedPreference(const char* preference_name); 139 static bool IsOldMigratedPreference(const char* old_preference_name); 140 141 // Do we have an active association between the preferences and sync models? 142 // Set when start syncing, reset in StopSyncing. While this is not set, we 143 // ignore any local preference changes (when we start syncing we will look 144 // up the most recent values anyways). 145 bool models_associated_; 146 147 // Whether we're currently processing changes from the syncer. While this is 148 // true, we ignore any local preference changes, since we triggered them. 149 bool processing_syncer_changes_; 150 151 // A set of preference names. 152 typedef std::set<std::string> PreferenceSet; 153 154 // All preferences that have registered as being syncable with this profile. 155 PreferenceSet registered_preferences_; 156 157 // The preferences that are currently synced (excludes those preferences 158 // that have never had sync data and currently have default values or are 159 // policy controlled). 160 // Note: this set never decreases, only grows to eventually match 161 // registered_preferences_ as more preferences are synced. It determines 162 // whether a preference change should update an existing sync node or create 163 // a new sync node. 164 PreferenceSet synced_preferences_; 165 166 // The PrefService we are syncing to. 167 PrefServiceSyncable* pref_service_; 168 169 // Sync's syncer::SyncChange handler. We push all our changes through this. 170 scoped_ptr<syncer::SyncChangeProcessor> sync_processor_; 171 172 // Sync's error handler. We use this to create sync errors. 173 scoped_ptr<syncer::SyncErrorFactory> sync_error_factory_; 174 175 // The datatype that this associator is responible for, either PREFERENCES or 176 // PRIORITY_PREFERENCES. 177 syncer::ModelType type_; 178 179 private: 180 // Map prefs to lists of observers. Observers will receive notification when 181 // a pref changes, including the detail of whether or not the change came 182 // from sync. 183 typedef ObserverList<SyncedPrefObserver> SyncedPrefObserverList; 184 typedef base::hash_map<std::string, SyncedPrefObserverList*> 185 SyncedPrefObserverMap; 186 187 void NotifySyncedPrefObservers(const std::string& path, bool from_sync) const; 188 189 SyncedPrefObserverMap synced_pref_observers_; 190 191 DISALLOW_COPY_AND_ASSIGN(PrefModelAssociator); 192 }; 193 194 #endif // CHROME_BROWSER_PREFS_PREF_MODEL_ASSOCIATOR_H_ 195