ui/app_list/search/dictionary_data_store.h

   1 // Copyright 2013 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 UI_APP_LIST_SEARCH_DICTIONARY_DATA_STORE_H_
   6 #define UI_APP_LIST_SEARCH_DICTIONARY_DATA_STORE_H_
   7
   8 #include <string>
   9 #include <vector>
  10
  11 #include "base/basictypes.h"
  12 #include "base/callback_forward.h"
  13 #include "base/files/file_path.h"
  14 #include "base/files/important_file_writer.h"
  15 #include "base/memory/ref_counted.h"
  16 #include "base/memory/scoped_ptr.h"
  17 #include "ui/app_list/app_list_export.h"
  18
  19 namespace base {
  20 class DictionaryValue;
  21 class SequencedTaskRunner;
  22 class SequencedWorkerPool;
  23 }
  24
  25 namespace app_list {
  26
  27 // A simple JSON store to persist a dictionary.
  28 class APP_LIST_EXPORT DictionaryDataStore
  29     : public base::RefCountedThreadSafe<DictionaryDataStore>,
  30       public base::ImportantFileWriter::DataSerializer {
  31  public:
  32   typedef base::Callback<void(scoped_ptr<base::DictionaryValue>)>
  33       OnLoadedCallback;
  34   typedef base::Closure OnFlushedCallback;
  35
  36   DictionaryDataStore(const base::FilePath& data_file,
  37                       base::SequencedWorkerPool* worker_pool);
  38
  39   // Flushes pending writes.
  40   void Flush(const OnFlushedCallback& on_flushed);
  41
  42   // Reads the persisted data from disk asynchronously. |on_read| is called
  43   // with the loaded and parsed data. If there is an error, |on_read| is called
  44   // without data.
  45   void Load(const OnLoadedCallback& on_loaded);
  46
  47   // Schedule a job to persist the cached dictionary.
  48   void ScheduleWrite();
  49
  50   // Used to get a pointer to the cached dictionary. Changes to this dictionary
  51   // will not be persisted unless ScheduleWrite() is called.
  52   base::DictionaryValue* cached_dict() { return cached_dict_.get(); }
  53
  54  private:
  55   friend class base::RefCountedThreadSafe<DictionaryDataStore>;
  56
  57   ~DictionaryDataStore() override;
  58
  59   // Reads data from backing file.
  60   scoped_ptr<base::DictionaryValue> LoadOnBlockingPool();
  61
  62   // ImportantFileWriter::DataSerializer overrides:
  63   bool SerializeData(std::string* data) override;
  64
  65   base::FilePath data_file_;
  66   scoped_refptr<base::SequencedTaskRunner> file_task_runner_;
  67   scoped_ptr<base::ImportantFileWriter> writer_;
  68
  69   // Cached JSON dictionary to serve read and incremental change calls.
  70   scoped_ptr<base::DictionaryValue> cached_dict_;
  71
  72   base::SequencedWorkerPool* worker_pool_;
  73
  74   DISALLOW_COPY_AND_ASSIGN(DictionaryDataStore);
  75 };
  76
  77 }  // namespace app_list
  78
  79 #endif  // UI_APP_LIST_SEARCH_DICTIONARY_DATA_STORE_H_