Compressed activity log database storage

chrome/browser/extensions/activity_log/counting_policy.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 CHROME_BROWSER_EXTENSIONS_ACTIVITY_LOG_COUNTING_POLICY_H_
+#define CHROME_BROWSER_EXTENSIONS_ACTIVITY_LOG_COUNTING_POLICY_H_
+
+#include <string>
+
+#include "base/containers/hash_tables.h"
+#include "chrome/browser/extensions/activity_log/activity_database.h"
+#include "chrome/browser/extensions/activity_log/activity_log_policy.h"
+#include "chrome/browser/extensions/activity_log/database_interned_string.h"
+
+namespace extensions {
+
+// A policy for logging the stream of actions, but without arguments.
+class CountingPolicy : public ActivityLogDatabasePolicy {
+ public:
+  explicit CountingPolicy(Profile* profile);
+  virtual ~CountingPolicy();
+
+  virtual void ProcessAction(scoped_refptr<Action> action) OVERRIDE;
+
+  virtual void ReadData(
+      const std::string& extension_id,
+      const int day,
+      const base::Callback
+          <void(scoped_ptr<Action::ActionVector>)>& callback) OVERRIDE;
+
+  virtual void Close() OVERRIDE;
+
+  // Gets or sets the amount of time that old records are kept in the database.
+  const base::TimeDelta& retention_time() const { return retention_time_; }
+  void set_retention_time(const base::TimeDelta& delta) {
+    retention_time_ = delta;
+  }
+
+  // The main database table, and the name for a read-only view that
+  // decompresses string values for easier parsing.
+  static const char* kTableName;
+  static const char* kReadViewName;
+
+ protected:
+  // The ActivityDatabase::Delegate interface.  These are always called from
+  // the database thread.
+  virtual bool InitDatabase(sql::Connection* db) OVERRIDE;
+  virtual bool FlushDatabase(sql::Connection* db) OVERRIDE;
+  virtual void OnDatabaseFailure() OVERRIDE;
+  virtual void OnDatabaseClose() OVERRIDE;
+
+ private:
+  // Adds an Action to those to be written out; this is an internal method used
+  // by ProcessAction and is called on the database thread.
+  void QueueAction(scoped_refptr<Action> action);
+
+  // Internal method to read data from the database; called on the database
+  // thread.
+  scoped_ptr<Action::ActionVector> DoReadData(
+      const std::string& extension_id,
+      const int days_ago);
+
+  // Cleans old records from the activity log database.
+  bool CleanOlderThan(sql::Connection* db, const base::Time& cutoff);
+
+  // Cleans unused interned strings from the database.  This should be run
+  // after deleting rows from the main log table to clean out stale values.
+  bool CleanStringTables(sql::Connection* db);
+
+  // API calls for which complete arguments should be logged.
+  std::set<std::string> api_arg_whitelist_;
+
+  // Tables for mapping strings to integers for shrinking database storage
+  // requirements.  URLs are kept in a separate table from other strings to
+  // make history clearing simpler.
+  DatabaseStringTable string_table_;
+  DatabaseStringTable url_table_;
+
+  // Tracks any pending updates to be written to the database, if write
+  // batching is turned on.  Should only be accessed from the database thread.
+  // TODO(mvrable): Do in-memory aggregation as well.
+  Action::ActionVector queued_actions_;
+
+  // Whether the policy is in the process of being shut down.
+  bool closing_;
+
+  // The amount of time old activity log records should be kept in the
+  // database.  This time is subtracted from the current time, rounded down to
+  // midnight, and rows older than this are deleted from the database when
+  // cleaning runs.
+  base::TimeDelta retention_time_;
+
+  // The time at which old activity log records were last cleaned out of the
+  // database (only tracked for this browser session).  Old records are deleted
+  // on the first database flush, and then every 12 hours subsequently.
+  base::Time last_database_cleaning_time_;
+
+  FRIEND_TEST_ALL_PREFIXES(CountingPolicyTest, MergingAndExpiring);
+};
+
+}  // namespace extensions
+
+#endif  // CHROME_BROWSER_EXTENSIONS_ACTIVITY_LOG_COUNTING_POLICY_H_