Home | History | Annotate | Download | only in prefs 
      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_PREFS_LEVELDB_PREF_STORE_H_
      6 #define CHROME_BROWSER_PREFS_LEVELDB_PREF_STORE_H_
      7 
      8 #include <set>
      9 #include <string>
     10 
     11 #include "base/basictypes.h"
     12 #include "base/compiler_specific.h"
     13 #include "base/files/file_path.h"
     14 #include "base/memory/scoped_ptr.h"
     15 #include "base/message_loop/message_loop_proxy.h"
     16 #include "base/observer_list.h"
     17 #include "base/prefs/persistent_pref_store.h"
     18 #include "base/prefs/pref_value_map.h"
     19 #include "base/timer/timer.h"
     20 
     21 namespace base {
     22 class DictionaryValue;
     23 class SequencedTaskRunner;
     24 class Value;
     25 }
     26 
     27 namespace leveldb {
     28 class DB;
     29 }
     30 
     31 // A writable PrefStore implementation that is used for user preferences.
     32 class LevelDBPrefStore : public PersistentPrefStore {
     33  public:
     34   // |sequenced_task_runner| is must be a shutdown-blocking task runner, ideally
     35   // created by GetTaskRunnerForFile() method above.
     36   LevelDBPrefStore(const base::FilePath& pref_filename,
     37                    base::SequencedTaskRunner* sequenced_task_runner);
     38 
     39   // PrefStore overrides:
     40   virtual bool GetValue(const std::string& key,
     41                         const base::Value** result) const OVERRIDE;
     42   virtual void AddObserver(PrefStore::Observer* observer) OVERRIDE;
     43   virtual void RemoveObserver(PrefStore::Observer* observer) OVERRIDE;
     44   virtual bool HasObservers() const OVERRIDE;
     45   virtual bool IsInitializationComplete() const OVERRIDE;
     46 
     47   // PersistentPrefStore overrides:
     48   virtual bool GetMutableValue(const std::string& key,
     49                                base::Value** result) OVERRIDE;
     50   // Takes ownership of value.
     51   virtual void SetValue(const std::string& key, base::Value* value) OVERRIDE;
     52   virtual void SetValueSilently(const std::string& key,
     53                                 base::Value* value) OVERRIDE;
     54   virtual void RemoveValue(const std::string& key) OVERRIDE;
     55   virtual bool ReadOnly() const OVERRIDE;
     56   virtual PrefReadError GetReadError() const OVERRIDE;
     57   virtual PrefReadError ReadPrefs() OVERRIDE;
     58   virtual void ReadPrefsAsync(ReadErrorDelegate* error_delegate) OVERRIDE;
     59   virtual void CommitPendingWrite() OVERRIDE;
     60   virtual void ReportValueChanged(const std::string& key) OVERRIDE;
     61 
     62  private:
     63   struct ReadingResults;
     64   class FileThreadSerializer;
     65 
     66   virtual ~LevelDBPrefStore();
     67 
     68   static scoped_ptr<ReadingResults> DoReading(const base::FilePath& path);
     69   static void OpenDB(const base::FilePath& path,
     70                      ReadingResults* reading_results);
     71   void OnStorageRead(scoped_ptr<ReadingResults> reading_results);
     72 
     73   void PersistFromUIThread();
     74   void RemoveFromUIThread(const std::string& key);
     75   void ScheduleWrite();
     76 
     77   void SetValueInternal(const std::string& key,
     78                         base::Value* value,
     79                         bool notify);
     80   void NotifyObservers(const std::string& key);
     81   void MarkForInsertion(const std::string& key, const std::string& value);
     82   void MarkForDeletion(const std::string& key);
     83 
     84   base::FilePath path_;
     85 
     86   const scoped_refptr<base::SequencedTaskRunner> sequenced_task_runner_;
     87   const scoped_refptr<base::SequencedTaskRunner> original_task_runner_;
     88 
     89   PrefValueMap prefs_;
     90 
     91   bool read_only_;
     92 
     93   ObserverList<PrefStore::Observer, true> observers_;
     94 
     95   scoped_ptr<ReadErrorDelegate> error_delegate_;
     96 
     97   bool initialized_;
     98   PrefReadError read_error_;
     99 
    100   // This object is created on the UI thread right after preferences are loaded
    101   // from disk. A message to delete it is sent to the FILE thread by
    102   // ~LevelDBPrefStore.
    103   scoped_ptr<FileThreadSerializer> serializer_;
    104 
    105   // Changes are accumulated in |keys_to_delete_| and |keys_to_set_| and are
    106   // stored in the database according to |timer_|.
    107   std::set<std::string> keys_to_delete_;
    108   std::map<std::string, std::string> keys_to_set_;
    109   base::OneShotTimer<LevelDBPrefStore> timer_;
    110 
    111   base::WeakPtrFactory<LevelDBPrefStore> weak_ptr_factory_;
    112 
    113   DISALLOW_COPY_AND_ASSIGN(LevelDBPrefStore);
    114 };
    115 
    116 #endif  // CHROME_BROWSER_PREFS_LEVELDB_PREF_STORE_H_
    117