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      1 // Copyright 2013 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #ifndef CHROME_BROWSER_EXTENSIONS_ACTIVITY_LOG_COUNTING_POLICY_H_
      6 #define CHROME_BROWSER_EXTENSIONS_ACTIVITY_LOG_COUNTING_POLICY_H_
      7 
      8 #include <string>
      9 
     10 #include "base/containers/hash_tables.h"
     11 #include "chrome/browser/extensions/activity_log/activity_database.h"
     12 #include "chrome/browser/extensions/activity_log/activity_log_policy.h"
     13 #include "chrome/browser/extensions/activity_log/database_string_table.h"
     14 
     15 namespace extensions {
     16 
     17 // A policy for logging the stream of actions, but with most arguments stripped
     18 // out (to improve privacy and reduce database size) and with multiple
     19 // identical rows combined together using a count column to track the total
     20 // number of repetitions.  Identical rows within the same day are merged, but
     21 // actions on separate days are kept distinct.  Data is kept for up to a few
     22 // days then deleted.
     23 class CountingPolicy : public ActivityLogDatabasePolicy {
     24  public:
     25   explicit CountingPolicy(Profile* profile);
     26   virtual ~CountingPolicy();
     27 
     28   virtual void ProcessAction(scoped_refptr<Action> action) OVERRIDE;
     29 
     30   virtual void ReadFilteredData(
     31       const std::string& extension_id,
     32       const Action::ActionType type,
     33       const std::string& api_name,
     34       const std::string& page_url,
     35       const std::string& arg_url,
     36       const int days_ago,
     37       const base::Callback
     38           <void(scoped_ptr<Action::ActionVector>)>& callback) OVERRIDE;
     39 
     40   virtual void Close() OVERRIDE;
     41 
     42   // Gets or sets the amount of time that old records are kept in the database.
     43   const base::TimeDelta& retention_time() const { return retention_time_; }
     44   void set_retention_time(const base::TimeDelta& delta) {
     45     retention_time_ = delta;
     46   }
     47 
     48   // Clean the URL data stored for this policy.
     49   virtual void RemoveURLs(const std::vector<GURL>&) OVERRIDE;
     50 
     51   // Clean the data related to this extension for this policy.
     52   virtual void RemoveExtensionData(const std::string& extension_id) OVERRIDE;
     53 
     54   // Delete everything in the database.
     55   virtual void DeleteDatabase() OVERRIDE;
     56 
     57   // The main database table, and the name for a read-only view that
     58   // decompresses string values for easier parsing.
     59   static const char* kTableName;
     60   static const char* kReadViewName;
     61 
     62  protected:
     63   // The ActivityDatabase::Delegate interface.  These are always called from
     64   // the database thread.
     65   virtual bool InitDatabase(sql::Connection* db) OVERRIDE;
     66   virtual bool FlushDatabase(sql::Connection* db) OVERRIDE;
     67   virtual void OnDatabaseFailure() OVERRIDE;
     68   virtual void OnDatabaseClose() OVERRIDE;
     69 
     70  private:
     71   // A type used to track pending writes to the database.  The key is an action
     72   // to write; the value is the amount by which the count field should be
     73   // incremented in the database.
     74   typedef std::map<scoped_refptr<Action>, int, ActionComparatorExcludingTime>
     75       ActionQueue;
     76 
     77   // Adds an Action to those to be written out; this is an internal method used
     78   // by ProcessAction and is called on the database thread.
     79   void QueueAction(scoped_refptr<Action> action);
     80 
     81   // Internal method to read data from the database; called on the database
     82   // thread.
     83   scoped_ptr<Action::ActionVector> DoReadFilteredData(
     84       const std::string& extension_id,
     85       const Action::ActionType type,
     86       const std::string& api_name,
     87       const std::string& page_url,
     88       const std::string& arg_url,
     89       const int days_ago);
     90 
     91   // The implementation of RemoveURLs; this must only run on the database
     92   // thread.
     93   void DoRemoveURLs(const std::vector<GURL>& restrict_urls);
     94 
     95   // The implementation of RemoveExtensionData; this must only run on the
     96   // database thread.
     97   void DoRemoveExtensionData(const std::string& extension_id);
     98 
     99   // The implementation of DeleteDatabase; called on the database thread.
    100   void DoDeleteDatabase();
    101 
    102   // Cleans old records from the activity log database.
    103   bool CleanOlderThan(sql::Connection* db, const base::Time& cutoff);
    104 
    105   // Cleans unused interned strings from the database.  This should be run
    106   // after deleting rows from the main log table to clean out stale values.
    107   bool CleanStringTables(sql::Connection* db);
    108 
    109   // API calls for which complete arguments should be logged.
    110   Util::ApiSet api_arg_whitelist_;
    111 
    112   // Tables for mapping strings to integers for shrinking database storage
    113   // requirements.  URLs are kept in a separate table from other strings to
    114   // make history clearing simpler.
    115   DatabaseStringTable string_table_;
    116   DatabaseStringTable url_table_;
    117 
    118   // Tracks any pending updates to be written to the database, if write
    119   // batching is turned on.  Should only be accessed from the database thread.
    120   ActionQueue queued_actions_;
    121 
    122   // All queued actions must fall on the same day, so that we do not
    123   // accidentally aggregate actions that should be kept separate.
    124   // queued_actions_date_ is the date (timestamp at local midnight) of all the
    125   // actions in queued_actions_.
    126   base::Time queued_actions_date_;
    127 
    128   // The amount of time old activity log records should be kept in the
    129   // database.  This time is subtracted from the current time, rounded down to
    130   // midnight, and rows older than this are deleted from the database when
    131   // cleaning runs.
    132   base::TimeDelta retention_time_;
    133 
    134   // The time at which old activity log records were last cleaned out of the
    135   // database (only tracked for this browser session).  Old records are deleted
    136   // on the first database flush, and then every 12 hours subsequently.
    137   base::Time last_database_cleaning_time_;
    138 
    139   friend class CountingPolicyTest;
    140   FRIEND_TEST_ALL_PREFIXES(CountingPolicyTest, EarlyFlush);
    141   FRIEND_TEST_ALL_PREFIXES(CountingPolicyTest, MergingAndExpiring);
    142   FRIEND_TEST_ALL_PREFIXES(CountingPolicyTest, StringTableCleaning);
    143 };
    144 
    145 }  // namespace extensions
    146 
    147 #endif  // CHROME_BROWSER_EXTENSIONS_ACTIVITY_LOG_COUNTING_POLICY_H_
    148