Redirect handling in resource prefetch predictor

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 80 matching lines @@
     // 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;
   };
   // Map from primary key to PrefetchData for the key.
   typedef std::map<std::string, PrefetchData> PrefetchDataMap;
 
+  struct RedirectStatRow {
+    RedirectStatRow();
+    RedirectStatRow(const RedirectStatRow& other);
+
+    std::string final_redirect;
+    size_t number_of_hits;
+    size_t number_of_misses;
+    size_t consecutive_misses;
+  };
+  typedef std::vector<RedirectStatRow> RedirectStatRows;

[mattcary, 2016/09/09 13:19:21]

Would prefer not to typedef the vector. You don't save that much space versus
the explicit type, and it obscures things like having a vector in the copyable
RedirectData structure.

It's a little different than typedef'ing the map type, because that encodes
additional type information---eg, what the key is. In other words, there's
multiple ways to make a map of PrefetchData, so it's nice to standardize. That's
not true with a vector.

+
+  struct RedirectData {
+    RedirectData(PrefetchKeyType key_type, const std::string& primary_key);
+    RedirectData(const RedirectData& other);
+    ~RedirectData();
+
+    bool is_host() const { return key_type == PREFETCH_KEY_TYPE_HOST; }
+
+    PrefetchKeyType key_type;
+    std::string primary_key;
+    base::Time last_visit;
+    RedirectStatRows redirect_stats;
+  };
+  typedef std::map<std::string, RedirectData> RedirectDataMap;
+
   // Returns data for all Urls and Hosts.
   virtual void GetAllData(PrefetchDataMap* url_data_map,
-                          PrefetchDataMap* host_data_map);
+                          PrefetchDataMap* host_data_map,
+                          RedirectDataMap* url_redirect_data_map,
+                          RedirectDataMap* host_redirect_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);
+  virtual void UpdatePrefetchData(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);
 
   // Wrapper over DeleteData for convenience.
   virtual void DeleteSingleDataPoint(const std::string& key,
                                      PrefetchKeyType key_type);
 
   // Deletes all data in all the tables.
@@ skipping 11 matching lines @@
                            DatabaseIsResetWhenIncompatible);
 
   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);
+  bool UpdatePrefetchDataHelper(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.
   static bool StringsAreSmallerThanDBLimit(const PrefetchData& data);
+  static bool StringsAreSmallerThanDBLimit(const RedirectData& data);
 
   // PredictorTableBase methods.
   void CreateTableIfNonExistent() override;
   void LogDatabaseStats() override;
 
   // Database version. Always increment it when any change is made to the data
   // schema (including the .proto).
   static constexpr int kDatabaseVersion = 2;
 
   static bool DropTablesIfOutdated(sql::Connection* db);
@@ skipping 11 matching lines @@
   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_