chrome/browser/predictors/resource_prefetch_predictor_tables.h

   1 // Copyright (c) 2012 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_PREDICTORS_RESOURCE_PREFETCH_PREDICTOR_TABLES_H_
   6 #define CHROME_BROWSER_PREDICTORS_RESOURCE_PREFETCH_PREDICTOR_TABLES_H_
   7
   8
   9 #include <map>
  10 #include <string>
  11 #include <vector>
  12
  13 #include "base/time/time.h"
  14 #include "chrome/browser/predictors/predictor_table_base.h"
  15 #include "chrome/browser/predictors/resource_prefetch_common.h"
  16 #include "url/gurl.h"
  17 #include "webkit/common/resource_type.h"
  18
  19 namespace sql {
  20 class Statement;
  21 }
  22
  23 namespace predictors {
  24
  25 // Interface for database tables used by the ResourcePrefetchPredictor.
  26 // All methods except the constructor and destructor need to be called on the DB
  27 // thread.
  28 //
  29 // Currently manages:
  30 //  - UrlResourceTable - resources per Urls.
  31 //  - UrlMetadataTable - misc data for Urls (like last visit time).
  32 //  - HostResourceTable - resources per host.
  33 //  - HostMetadataTable - misc data for hosts.
  34 class ResourcePrefetchPredictorTables : public PredictorTableBase {
  35  public:
  36   // Used in the UrlResourceTable and HostResourceTable to store resources
  37   // required for the page or host.
  38   struct ResourceRow {
  39     ResourceRow();
  40     ResourceRow(const ResourceRow& other);
  41     ResourceRow(const std::string& main_frame_url,
  42                 const std::string& resource_url,
  43                 ResourceType::Type resource_type,
  44                 int number_of_hits,
  45                 int number_of_misses,
  46                 int consecutive_misses,
  47                 double average_position);
  48     void UpdateScore();
  49     bool operator==(const ResourceRow& rhs) const;
  50
  51     // Stores the host for host based data, main frame Url for the Url based
  52     // data. This field is cleared for efficiency reasons and the code outside
  53     // this class should not assume it is set.
  54     std::string primary_key;
  55
  56     GURL resource_url;
  57     ResourceType::Type resource_type;
  58     int number_of_hits;
  59     int number_of_misses;
  60     int consecutive_misses;
  61     double average_position;
  62
  63     // Not stored.
  64     float score;
  65   };
  66   typedef std::vector<ResourceRow> ResourceRows;
  67
  68   // Sorts the ResourceRows by score, descending.
  69   struct ResourceRowSorter {
  70     bool operator()(const ResourceRow& x, const ResourceRow& y) const;
  71   };
  72
  73   // Aggregated data for a Url or Host. Although the data differs slightly, we
  74   // store them in the same structure, because most of the fields are common and
  75   // it allows us to use the same functions.
  76   struct PrefetchData {
  77     PrefetchData(PrefetchKeyType key_type, const std::string& primary_key);
  78     PrefetchData(const PrefetchData& other);
  79     ~PrefetchData();
  80     bool operator==(const PrefetchData& rhs) const;
  81
  82     bool is_host() const { return key_type == PREFETCH_KEY_TYPE_HOST; }
  83
  84     // Is the data a host as opposed to a Url?
  85     PrefetchKeyType key_type;  // Not const to be able to assign.
  86     std::string primary_key;  // is_host() ? main frame url : host.
  87
  88     base::Time last_visit;
  89     ResourceRows resources;
  90   };
  91   // Map from primary key to PrefetchData for the key.
  92   typedef std::map<std::string, PrefetchData> PrefetchDataMap;
  93
  94   // Returns data for all Urls and Hosts.
  95   virtual void GetAllData(PrefetchDataMap* url_data_map,
  96                           PrefetchDataMap* host_data_map);
  97
  98   // Updates data for a Url and a host. If either of the |url_data| or
  99   // |host_data| has an empty primary key, it will be ignored.
 100   // Note that the Urls and primary key in |url_data| and |host_data| should be
 101   // less than |kMaxStringLength| in length.
 102   virtual void UpdateData(const PrefetchData& url_data,
 103                           const PrefetchData& host_data);
 104
 105   // Delete data for the input |urls| and |hosts|.
 106   virtual void DeleteData(const std::vector<std::string>& urls,
 107                   const std::vector<std::string>& hosts);
 108
 109   // Wrapper over DeleteData for convenience.
 110   virtual void DeleteSingleDataPoint(const std::string& key,
 111                                      PrefetchKeyType key_type);
 112
 113   // Deletes all data in all the tables.
 114   virtual void DeleteAllData();
 115
 116   // The maximum length of the string that can be stored in the DB.
 117   static const size_t kMaxStringLength;
 118
 119  private:
 120   friend class PredictorDatabaseInternal;
 121   friend class MockResourcePrefetchPredictorTables;
 122
 123   ResourcePrefetchPredictorTables();
 124   virtual ~ResourcePrefetchPredictorTables();
 125
 126   // Helper functions below help perform functions on the Url and host table
 127   // using the same code.
 128   void GetAllDataHelper(PrefetchKeyType key_type,
 129                         PrefetchDataMap* data_map,
 130                         std::vector<std::string>* to_delete);
 131   bool UpdateDataHelper(const PrefetchData& data);
 132   void DeleteDataHelper(PrefetchKeyType key_type,
 133                         const std::vector<std::string>& keys);
 134
 135   // Returns true if the strings in the |data| are less than |kMaxStringLength|
 136   // in length.
 137   bool StringsAreSmallerThanDBLimit(const PrefetchData& data) const;
 138
 139   // PredictorTableBase methods.
 140   virtual void CreateTableIfNonExistent() OVERRIDE;
 141   virtual void LogDatabaseStats() OVERRIDE;
 142
 143   // Helpers to return Statements for cached Statements. The caller must take
 144   // ownership of the return Statements.
 145   sql::Statement* GetUrlResourceDeleteStatement();
 146   sql::Statement* GetUrlResourceUpdateStatement();
 147   sql::Statement* GetUrlMetadataDeleteStatement();
 148   sql::Statement* GetUrlMetadataUpdateStatement();
 149
 150   sql::Statement* GetHostResourceDeleteStatement();
 151   sql::Statement* GetHostResourceUpdateStatement();
 152   sql::Statement* GetHostMetadataDeleteStatement();
 153   sql::Statement* GetHostMetadataUpdateStatement();
 154
 155   DISALLOW_COPY_AND_ASSIGN(ResourcePrefetchPredictorTables);
 156 };
 157
 158 }  // namespace predictors
 159
 160 #endif  // CHROME_BROWSER_PREDICTORS_RESOURCE_PREFETCH_PREDICTOR_TABLES_H_