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