chrome/browser/supervised_user/supervised_user_settings_service.h

   1 // Copyright 2014 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_SUPERVISED_USER_SUPERVISED_USER_SETTINGS_SERVICE_H_
   6 #define CHROME_BROWSER_SUPERVISED_USER_SUPERVISED_USER_SETTINGS_SERVICE_H_
   7
   8 #include <string>
   9 #include <vector>
  10
  11 #include "base/callback.h"
  12 #include "base/memory/ref_counted.h"
  13 #include "base/memory/scoped_ptr.h"
  14 #include "base/prefs/pref_store.h"
  15 #include "base/values.h"
  16 #include "chrome/browser/supervised_user/supervised_users.h"
  17 #include "components/keyed_service/core/keyed_service.h"
  18 #include "sync/api/syncable_service.h"
  19
  20 class PersistentPrefStore;
  21 class Profile;
  22
  23 namespace base {
  24 class FilePath;
  25 class SequencedTaskRunner;
  26 }
  27
  28 // This class syncs supervised user settings from a server, which are mapped to
  29 // preferences. The downloaded settings are persisted in a PrefStore (which is
  30 // not directly hooked up to the PrefService; it's just used internally).
  31 // Settings are key-value pairs, where the key uniquely identifies the setting.
  32 // The value is a string containing a JSON serialization of an arbitrary value,
  33 // which is the value of the setting.
  34 //
  35 // There are two kinds of settings handled by this class: Atomic and split
  36 // settings.
  37 // Atomic settings consist of a single key (which will be mapped to a pref key)
  38 // and a single (arbitrary) value.
  39 // Split settings encode a dictionary value and are stored as multiple Sync
  40 // items, one for each dictionary entry. The key for each of these Sync items
  41 // is the key of the split setting, followed by a separator (':') and the key
  42 // for the dictionary entry. The value of the Sync item is the value of the
  43 // dictionary entry.
  44 //
  45 // As an example, a split setting with key "Moose" and value
  46 //   {
  47 //     "foo": "bar",
  48 //     "baz": "blurp"
  49 //   }
  50 // would be encoded as two sync items, one with key "Moose:foo" and value "bar",
  51 // and one with key "Moose:baz" and value "blurp".
  52 class SupervisedUserSettingsService : public KeyedService,
  53                                       public syncer::SyncableService,
  54                                       public PrefStore::Observer {
  55  public:
  56   // A callback whose first parameter is a dictionary containing all supervised
  57   // user settings. If the dictionary is NULL, it means that the service is
  58   // inactive, i.e. the user is not supervised.
  59   typedef base::Callback<void(const base::DictionaryValue*)> SettingsCallback;
  60
  61   SupervisedUserSettingsService();
  62   virtual ~SupervisedUserSettingsService();
  63
  64   // Initializes the service by loading its settings from a file underneath the
  65   // |profile_path|. File I/O will be serialized via the
  66   // |sequenced_task_runner|. If |load_synchronously| is true, the settings will
  67   // be loaded synchronously, otherwise asynchronously.
  68   void Init(base::FilePath profile_path,
  69             base::SequencedTaskRunner* sequenced_task_runner,
  70             bool load_synchronously);
  71
  72   // Initializes the service by loading its settings from the |pref_store|.
  73   // Use this method in tests to inject a different PrefStore than the
  74   // default one.
  75   void Init(scoped_refptr<PersistentPrefStore> pref_store);
  76
  77   // Adds a callback to be called when supervised user settings are initially
  78   // available, or when they change.
  79   void Subscribe(const SettingsCallback& callback);
  80
  81   // Activates/deactivates the service. This is called by the
  82   // SupervisedUserService when it is (de)activated.
  83   void SetActive(bool active);
  84
  85   // Whether supervised user settings are available.
  86   bool IsReady();
  87
  88   // Clears all supervised user settings and items.
  89   void Clear();
  90
  91   // Constructs a key for a split supervised user setting from a prefix and a
  92   // variable key.
  93   static std::string MakeSplitSettingKey(const std::string& prefix,
  94                                          const std::string& key);
  95
  96   // Uploads an item to the Sync server. Items are the same data structure as
  97   // supervised user settings (i.e. key-value pairs, as described at the top of
  98   // the file), but they are only uploaded (whereas supervised user settings are
  99   // only downloaded), and never passed to the preference system.
 100   // An example of an uploaded item is an access request to a blocked URL.
 101   void UploadItem(const std::string& key, scoped_ptr<base::Value> value);
 102
 103   // Sets the setting with the given |key| to a copy of the given |value|.
 104   void SetLocalSettingForTesting(const std::string& key,
 105                                  scoped_ptr<base::Value> value);
 106
 107   // Public for testing.
 108   static syncer::SyncData CreateSyncDataForSetting(const std::string& name,
 109                                                    const base::Value& value);
 110
 111   // KeyedService implementation:
 112   virtual void Shutdown() OVERRIDE;
 113
 114   // SyncableService implementation:
 115   virtual syncer::SyncMergeResult MergeDataAndStartSyncing(
 116       syncer::ModelType type,
 117       const syncer::SyncDataList& initial_sync_data,
 118       scoped_ptr<syncer::SyncChangeProcessor> sync_processor,
 119       scoped_ptr<syncer::SyncErrorFactory> error_handler) OVERRIDE;
 120   virtual void StopSyncing(syncer::ModelType type) OVERRIDE;
 121   virtual syncer::SyncDataList GetAllSyncData(syncer::ModelType type) const
 122       OVERRIDE;
 123   virtual syncer::SyncError ProcessSyncChanges(
 124       const tracked_objects::Location& from_here,
 125       const syncer::SyncChangeList& change_list) OVERRIDE;
 126
 127   // PrefStore::Observer implementation:
 128   virtual void OnPrefValueChanged(const std::string& key) OVERRIDE;
 129   virtual void OnInitializationCompleted(bool success) OVERRIDE;
 130
 131  private:
 132   base::DictionaryValue* GetOrCreateDictionary(const std::string& key) const;
 133   base::DictionaryValue* GetAtomicSettings() const;
 134   base::DictionaryValue* GetSplitSettings() const;
 135   base::DictionaryValue* GetQueuedItems() const;
 136
 137   // Returns the dictionary where a given Sync item should be stored, depending
 138   // on whether the supervised user setting is atomic or split. In case of a
 139   // split setting, the split setting prefix of |key| is removed, so that |key|
 140   // can be used to update the returned dictionary.
 141   base::DictionaryValue* GetDictionaryAndSplitKey(std::string* key) const;
 142
 143   // Returns a dictionary with all supervised user settings if the service is
 144   // active, or NULL otherwise.
 145   scoped_ptr<base::DictionaryValue> GetSettings();
 146
 147   // Sends the settings to all subscribers. This method should be called by the
 148   // subclass whenever the settings change.
 149   void InformSubscribers();
 150
 151   // Used for persisting the settings. Unlike other PrefStores, this one is not
 152   // directly hooked up to the PrefService.
 153   scoped_refptr<PersistentPrefStore> store_;
 154
 155   bool active_;
 156
 157   // A set of local settings that are fixed and not configured remotely.
 158   scoped_ptr<base::DictionaryValue> local_settings_;
 159
 160   std::vector<SettingsCallback> subscribers_;
 161
 162   scoped_ptr<syncer::SyncChangeProcessor> sync_processor_;
 163   scoped_ptr<syncer::SyncErrorFactory> error_handler_;
 164
 165   DISALLOW_COPY_AND_ASSIGN(SupervisedUserSettingsService);
 166 };
 167
 168 #endif  // CHROME_BROWSER_SUPERVISED_USER_SUPERVISED_USER_SETTINGS_SERVICE_H_