predictors: Refactor the resource_prefetch_predictor database handling.

chrome/browser/predictors/resource_prefetch_predictor_tables.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROME_BROWSER_PREDICTORS_RESOURCE_PREFETCH_PREDICTOR_TABLES_H_
 #define CHROME_BROWSER_PREDICTORS_RESOURCE_PREFETCH_PREDICTOR_TABLES_H_
 
 #include <stddef.h>
 
 #include <map>
@@ skipping 21 matching lines @@
 // All methods except the constructor and destructor need to be called on the DB
 // thread.
 //
 // Currently manages:
 //  - UrlResourceTable - resources per Urls.
 //  - UrlMetadataTable - misc data for Urls (like last visit time).
 //  - HostResourceTable - resources per host.
 //  - HostMetadataTable - misc data for hosts.
 class ResourcePrefetchPredictorTables : public PredictorTableBase {
  public:
-  // Used in the UrlResourceTable and HostResourceTable to store resources
-  // required for the page or host.
-  struct ResourceRow {
-    ResourceRow();
-    ResourceRow(const ResourceRow& other);
-    ResourceRow(const std::string& main_frame_url,
-                const std::string& resource_url,
-                content::ResourceType resource_type,
-                int number_of_hits,
-                int number_of_misses,
-                int consecutive_misses,
-                double average_position,
-                net::RequestPriority priority,
-                bool has_validators,
-                bool always_revalidate);
-    void UpdateScore();
-    bool operator==(const ResourceRow& rhs) const;
-    static void FromProto(const ResourceData& proto, ResourceRow* row);
-    void ToProto(ResourceData* resource_data) const;
-
-    // Stores the host for host based data, main frame Url for the Url based
-    // data. This field is cleared for efficiency reasons and the code outside
-    // this class should not assume it is set.
-    std::string primary_key;
-
-    GURL resource_url;
-    content::ResourceType resource_type;
-    size_t number_of_hits;
-    size_t number_of_misses;
-    size_t consecutive_misses;
-    double average_position;
-    net::RequestPriority priority;
-    bool has_validators;
-    bool always_revalidate;
-
-    // Not stored.
-    float score;
-  };
-  typedef std::vector<ResourceRow> ResourceRows;
-
-  // Sorts the resource rows by score, decreasing.
-  static void SortResourceRows(ResourceRows* rows);
-
   // Aggregated data for a Url or Host. Although the data differs slightly, we
   // store them in the same structure, because most of the fields are common and
   // it allows us to use the same functions.
   struct PrefetchData {
     PrefetchData(PrefetchKeyType key_type, const std::string& primary_key);
     PrefetchData(const PrefetchData& other);
     ~PrefetchData();
-    bool operator==(const PrefetchData& rhs) const;
 
     bool is_host() const { return key_type == PREFETCH_KEY_TYPE_HOST; }
 
     // Is the data a host as opposed to a Url?
     PrefetchKeyType key_type;  // Not const to be able to assign.
     std::string primary_key;  // is_host() ? main frame url : host.
 
     base::Time last_visit;
-    ResourceRows resources;
+    std::vector<ResourceData> resources;
   };
+
+  // Sorts the resources by score, decreasing.
+  static void SortResources(std::vector<ResourceData>* resource);
+
+  // Updates the score of a resource.
+  static void UpdateResourceScore(ResourceData* resource);
+
   // Map from primary key to PrefetchData for the key.
   typedef std::map<std::string, PrefetchData> PrefetchDataMap;
 
   // Returns data for all Urls and Hosts.
   virtual void GetAllData(PrefetchDataMap* url_data_map,
                           PrefetchDataMap* host_data_map);
 
   // Updates data for a Url and a host. If either of the |url_data| or
   // |host_data| has an empty primary key, it will be ignored.
   // Note that the Urls and primary key in |url_data| and |host_data| should be
   // less than |kMaxStringLength| in length.
   virtual void UpdateData(const PrefetchData& url_data,
                           const PrefetchData& host_data);
 
   // Delete data for the input |urls| and |hosts|.
   virtual void DeleteData(const std::vector<std::string>& urls,
-                  const std::vector<std::string>& hosts);
+                          const std::vector<std::string>& hosts);
 
   // Wrapper over DeleteData for convenience.
   virtual void DeleteSingleDataPoint(const std::string& key,
                                      PrefetchKeyType key_type);
 
   // Deletes all data in all the tables.
   virtual void DeleteAllData();
 
   // The maximum length of the string that can be stored in the DB.
-  static const size_t kMaxStringLength;
+  static const size_t kMaxStringLength = 1024;
 
  private:
   friend class PredictorDatabaseInternal;
   friend class MockResourcePrefetchPredictorTables;
 
   ResourcePrefetchPredictorTables();
   ~ResourcePrefetchPredictorTables() override;
 
   // Helper functions below help perform functions on the Url and host table
   // using the same code.
   void GetAllDataHelper(PrefetchKeyType key_type,
                         PrefetchDataMap* data_map,
                         std::vector<std::string>* to_delete);
   bool UpdateDataHelper(const PrefetchData& data);
   void DeleteDataHelper(PrefetchKeyType key_type,
                         const std::vector<std::string>& keys);
 
   // Returns true if the strings in the |data| are less than |kMaxStringLength|
   // in length.
-  bool StringsAreSmallerThanDBLimit(const PrefetchData& data) const;
+  static bool StringsAreSmallerThanDBLimit(const PrefetchData& data);
 
   // PredictorTableBase methods.
   void CreateTableIfNonExistent() override;
   void LogDatabaseStats() override;
 
   bool DropTablesIfOutdated(sql::Connection* db);
 
   // Helpers to return Statements for cached Statements. The caller must take
   // ownership of the return Statements.
   sql::Statement* GetUrlResourceDeleteStatement();
   sql::Statement* GetUrlResourceUpdateStatement();
   sql::Statement* GetUrlMetadataDeleteStatement();
   sql::Statement* GetUrlMetadataUpdateStatement();
 
   sql::Statement* GetHostResourceDeleteStatement();
   sql::Statement* GetHostResourceUpdateStatement();
   sql::Statement* GetHostMetadataDeleteStatement();
   sql::Statement* GetHostMetadataUpdateStatement();
 
   DISALLOW_COPY_AND_ASSIGN(ResourcePrefetchPredictorTables);
 };
 
 }  // namespace predictors
 
 #endif  // CHROME_BROWSER_PREDICTORS_RESOURCE_PREFETCH_PREDICTOR_TABLES_H_