Precache tracking database

components/precache/core/precache_statistics_table.h

+// Copyright 2013 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 COMPONENTS_PRECACHE_CORE_PRECACHE_STATISTICS_TABLE_H_
+#define COMPONENTS_PRECACHE_CORE_PRECACHE_STATISTICS_TABLE_H_
+
+#include <map>
+
+#include "base/basictypes.h"
+#include "base/time/time.h"
+
+namespace sql {
+class Connection;
+}
+
+namespace precache {
+
+// Keeps track of daily precache statistics in a database table. To account for
+// differing time zones and leap seconds, days are counted as the number of 24
+// hour intervals that have passed since base::Time(0). Manages one table:
+// {
+//   date (primary key),
+//   downloaded_precache_motivated_bytes,
+//   downloaded_non_precache_bytes,
+//   downloaded_non_precache_bytes_cellular,
+//   saved_bytes,
+//   saved_bytes_cellular
+// }.
+class PrecacheStatisticsTable {
+ public:
+  // Struct of the statistics tracked by this class.
+  struct PrecacheStatistics {
+    // Initializes all statistics to zero.
+    PrecacheStatistics();
+    PrecacheStatistics(int64 downloaded_precache_motivated_bytes,
+                       int64 downloaded_non_precache_bytes,
+                       int64 downloaded_non_precache_bytes_cellular,
+                       int64 saved_bytes, int64 saved_bytes_cellular);
+    bool operator==(const PrecacheStatistics& other) const;
+
+    // Number of bytes downloaded over the network for fetches that were
+    // motivated by precaching.
+    int64 downloaded_precache_motivated_bytes;
+
+    // Number of bytes downloaded over any network for fetches that were not
+    // motivated by precaching.
+    int64 downloaded_non_precache_bytes;
+
+    // Number of bytes downloaded over cellular networks for fetches that were
+    // not motivated by precaching.
+    int64 downloaded_non_precache_bytes_cellular;
+
+    // Number of bytes that were served from the cache because of precaching,
+    // but would have been downloaded over the network otherwise.
+    int64 saved_bytes;
+
+    // Number of bytes that were served from the cache because of precaching,
+    // but would have been downloaded over a cellular network otherwise.
+    int64 saved_bytes_cellular;
+  };
+
+  typedef std::map<base::Time, PrecacheStatistics> PrecacheStatisticsMap;
+
+  PrecacheStatisticsTable();
+  ~PrecacheStatisticsTable();
+
+  // Initialize the precache statistics table for use with the specified
+  // database connection. The caller keeps ownership of |db|, and |db| must not
+  // be NULL. Init must be called before any other methods.
+  void Init(sql::Connection* db);
+
+  // Increase the daily statistics for the day of |time_on_day|. If a row for
+  // the day of |time_on_day| does not already exist, a new row is created.
+  void IncreaseDailyStats(const base::Time& time_on_day,
+                          const PrecacheStatistics& delta);
+
+  // Gets stored daily statistics for days up to but not including the day of
+  // |current_time|.
+  void GetOldStats(const base::Time& current_time,
+                   PrecacheStatisticsMap* stats_map);
+
+  // Deletes stored daily statistics for days up to but not including the day of
+  // |current_time|.
+  void DeleteOldStats(const base::Time& current_time);
+
+ private:
+  void CreateTableIfNonExistent();
+
+  // Non-owning pointer.
+  sql::Connection* db_;
+
+  DISALLOW_COPY_AND_ASSIGN(PrecacheStatisticsTable);
+};
+
+}  // namespace precache
+
+#endif  // COMPONENTS_PRECACHE_CORE_PRECACHE_STATISTICS_TABLE_H_