chrome/browser/prefs/leveldb_pref_store.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_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   bool GetValue(const std::string& key,
  41                 const base::Value** result) const override;
  42   void AddObserver(PrefStore::Observer* observer) override;
  43   void RemoveObserver(PrefStore::Observer* observer) override;
  44   bool HasObservers() const override;
  45   bool IsInitializationComplete() const override;
  46
  47   // PersistentPrefStore overrides:
  48   bool GetMutableValue(const std::string& key, base::Value** result) override;
  49   // Takes ownership of value.
  50   void SetValue(const std::string& key, base::Value* value) override;
  51   void SetValueSilently(const std::string& key, base::Value* value) override;
  52   void RemoveValue(const std::string& key) override;
  53   bool ReadOnly() const override;
  54   PrefReadError GetReadError() const override;
  55   PrefReadError ReadPrefs() override;
  56   void ReadPrefsAsync(ReadErrorDelegate* error_delegate) override;
  57   void CommitPendingWrite() override;
  58   void ReportValueChanged(const std::string& key) override;
  59
  60  private:
  61   struct ReadingResults;
  62   class FileThreadSerializer;
  63
  64   ~LevelDBPrefStore() override;
  65
  66   static scoped_ptr<ReadingResults> DoReading(const base::FilePath& path);
  67   static void OpenDB(const base::FilePath& path,
  68                      ReadingResults* reading_results);
  69   void OnStorageRead(scoped_ptr<ReadingResults> reading_results);
  70
  71   void PersistFromUIThread();
  72   void RemoveFromUIThread(const std::string& key);
  73   void ScheduleWrite();
  74
  75   void SetValueInternal(const std::string& key,
  76                         base::Value* value,
  77                         bool notify);
  78   void NotifyObservers(const std::string& key);
  79   void MarkForInsertion(const std::string& key, const std::string& value);
  80   void MarkForDeletion(const std::string& key);
  81
  82   base::FilePath path_;
  83
  84   const scoped_refptr<base::SequencedTaskRunner> sequenced_task_runner_;
  85   const scoped_refptr<base::SequencedTaskRunner> original_task_runner_;
  86
  87   PrefValueMap prefs_;
  88
  89   bool read_only_;
  90
  91   ObserverList<PrefStore::Observer, true> observers_;
  92
  93   scoped_ptr<ReadErrorDelegate> error_delegate_;
  94
  95   bool initialized_;
  96   PrefReadError read_error_;
  97
  98   // This object is created on the UI thread right after preferences are loaded
  99   // from disk. A message to delete it is sent to the FILE thread by
 100   // ~LevelDBPrefStore.
 101   scoped_ptr<FileThreadSerializer> serializer_;
 102
 103   // Changes are accumulated in |keys_to_delete_| and |keys_to_set_| and are
 104   // stored in the database according to |timer_|.
 105   std::set<std::string> keys_to_delete_;
 106   std::map<std::string, std::string> keys_to_set_;
 107   base::OneShotTimer<LevelDBPrefStore> timer_;
 108
 109   base::WeakPtrFactory<LevelDBPrefStore> weak_ptr_factory_;
 110
 111   DISALLOW_COPY_AND_ASSIGN(LevelDBPrefStore);
 112 };
 113
 114 #endif  // CHROME_BROWSER_PREFS_LEVELDB_PREF_STORE_H_