ui/app_list/search/history_data.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_HISTORY_DATA_H_
   6 #define UI_APP_LIST_SEARCH_HISTORY_DATA_H_
   7
   8 #include <deque>
   9 #include <map>
  10 #include <string>
  11
  12 #include "base/basictypes.h"
  13 #include "base/memory/scoped_ptr.h"
  14 #include "base/memory/weak_ptr.h"
  15 #include "base/observer_list.h"
  16 #include "base/time/time.h"
  17 #include "ui/app_list/app_list_export.h"
  18 #include "ui/app_list/search/history_types.h"
  19
  20 namespace app_list {
  21
  22 class HistoryDataObserver;
  23 class HistoryDataStore;
  24
  25 // HistoryData stores the associations of the user typed queries and launched
  26 // search result id. There are two types of association: primary and secondary.
  27 // Primary is a 1-to-1 mapping between the query and result id. Secondary
  28 // is a 1-to-many mapping and only kept the last 5 to limit the data size.
  29 // If an association is added for the first time, it is added as a primary
  30 // association. Further associations added to the same query are added as
  31 // secondary. However, if a secondary association is added twice in a row, it
  32 // is promoted to primary and the current primary mapping is demoted into
  33 // secondary.
  34 class APP_LIST_EXPORT HistoryData : public base::SupportsWeakPtr<HistoryData> {
  35  public:
  36   typedef std::deque<std::string> SecondaryDeque;
  37
  38   // Defines data to be associated with a query.
  39   struct APP_LIST_EXPORT Data {
  40     Data();
  41     ~Data();
  42
  43     // Primary result associated with the query.
  44     std::string primary;
  45
  46     // Secondary results associated with the query from oldest to latest.
  47     SecondaryDeque secondary;
  48
  49     // Last update time.
  50     base::Time update_time;
  51   };
  52   typedef std::map<std::string, Data> Associations;
  53
  54   // Constructor of HistoryData. |store| is the storage to persist the data.
  55   // |max_primary| is the maximum number of the most recent primary associations
  56   // to keep. |max_secondary| is the maximum number of secondary associations to
  57   // keep.
  58   HistoryData(HistoryDataStore* store,
  59               size_t max_primary,
  60               size_t max_secondary);
  61   ~HistoryData();
  62
  63   // Adds an association.
  64   void Add(const std::string& query, const std::string& result_id);
  65
  66   // Gets all known search results that were launched using the given |query|
  67   // or the queries that |query| is a prefix of.
  68   scoped_ptr<KnownResults> GetKnownResults(const std::string& query) const;
  69
  70   void AddObserver(HistoryDataObserver* observer);
  71   void RemoveObserver(HistoryDataObserver* observer);
  72
  73   const Associations& associations() const { return associations_; }
  74
  75  private:
  76   // Invoked from |store| with loaded data.
  77   void OnStoreLoaded(scoped_ptr<Associations> loaded_data);
  78
  79   // Trims the data to keep the most recent |max_primary_| queries.
  80   void TrimEntries();
  81
  82   HistoryDataStore* store_;  // Not owned.
  83   const size_t max_primary_;
  84   const size_t max_secondary_;
  85   base::ObserverList<HistoryDataObserver, true> observers_;
  86
  87   Associations associations_;
  88
  89   DISALLOW_COPY_AND_ASSIGN(HistoryData);
  90 };
  91
  92 }  // namespace app_list
  93
  94 #endif  // UI_APP_LIST_SEARCH_HISTORY_DATA_H_