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. Manages one
+// table { date (primary key), precached_bytes, downloaded_bytes,
+// downloaded_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 precached_bytes, int64 downloaded_bytes,
+                       int64 downloaded_bytes_cellular, int64 saved_bytes,
+                       int64 saved_bytes_cellular);
+    bool operator==(const PrecacheStatistics& other) const;
+
+    int64 precached_bytes;
+    int64 downloaded_bytes;
+    int64 downloaded_bytes_cellular;
+    int64 saved_bytes;
+    int64 saved_bytes_cellular;
+  };
+
+  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);
+
+  // Updates daily statistics after a fetch. If a row for the day of

[mmenke, 2013/10/29 18:23:34]

"Fetch" is ambiguous.  Particularly given that this isn't called for all cached
responses, but it is called for *some* cached responses.  I'm confused.

[sclittle, 2013/10/29 23:40:45]

Removed the concept of "fetch" from this method.

+  // |fetch_time| does not already exist, a new row is created.
+  void IncreaseStatsForFetch(
+      const base::Time& fetch_time,
+      const PrecacheStatistics& precache_statistics_change);
+
+  // Returns stored daily statistics for days between the day of |start_time|
+  // and the day of |end_time|, inclusive.
+  void GetAllStatsBetween(const base::Time& start_time,
+                          const base::Time& end_time,
+                          std::map<base::Time, PrecacheStatistics>* map);
+
+  // Deletes stored daily statistics for days between the day of |delete_begin|
+  // and the day of |delete_end|, inclusive.
+  void DeleteAllStatsBetween(const base::Time& delete_begin,
+                             const base::Time& delete_end);
+
+ private:
+  // Rounds |fetch_time| down to midnight of the start of the day of
+  // |fetch_time|, and returns the internal value.
+  static int64 GetKey(const base::Time& fetch_time);
+
+  void CreateTableIfNonExistent();
+
+  // Non-owning pointer.
+  sql::Connection* db_;
+
+  DISALLOW_COPY_AND_ASSIGN(PrecacheStatisticsTable);
+};
+
+}  // namespace precache
+
+#endif  // COMPONENTS_PRECACHE_CORE_PRECACHE_STATISTICS_TABLE_H_