chrome/browser/engagement/site_engagement_service.h

   1 // Copyright 2015 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_ENGAGEMENT_SITE_ENGAGEMENT_SERVICE_H_
   6 #define CHROME_BROWSER_ENGAGEMENT_SITE_ENGAGEMENT_SERVICE_H_
   7
   8 #include <map>
   9
  10 #include "base/gtest_prod_util.h"
  11 #include "base/macros.h"
  12 #include "base/time/default_clock.h"
  13 #include "base/time/time.h"
  14 #include "components/keyed_service/core/keyed_service.h"
  15
  16 namespace base {
  17 class DictionaryValue;
  18 }
  19
  20 class GURL;
  21 class Profile;
  22
  23 class SiteEngagementScore {
  24  public:
  25   // Keys used in the content settings dictionary.
  26   static const char* kRawScoreKey;
  27   static const char* kPointsAddedTodayKey;
  28   static const char* kLastEngagementTimeKey;
  29
  30   // The maximum number of points that are allowed.
  31   static const double kMaxPoints;
  32
  33   // The maximum number of points that can be accrued in one day.
  34   static const double kMaxPointsPerDay;
  35
  36   // The number of points given for a navigation.
  37   static const double kNavigationPoints;
  38
  39   // Decaying works by removing a portion of the score periodically. This
  40   // constant determines how often that happens.
  41   static const int kDecayPeriodInDays;
  42
  43   // How much the score decays after every kDecayPeriodInDays.
  44   static const double kDecayPoints;
  45
  46   // The SiteEngagementService does not take ownership of |clock|. It is the
  47   // responsibility of the caller to make sure |clock| outlives this
  48   // SiteEngagementScore.
  49   SiteEngagementScore(base::Clock* clock,
  50                       const base::DictionaryValue& score_dict);
  51   ~SiteEngagementScore();
  52
  53   double Score() const;
  54   void AddPoints(double points);
  55
  56   // Updates the content settings dictionary |score_dict| with the current score
  57   // fields. Returns true if |score_dict| changed, otherwise return false.
  58   bool UpdateScoreDict(base::DictionaryValue* score_dict);
  59
  60  private:
  61   friend class SiteEngagementScoreTest;
  62
  63   // This version of the constructor is used in unit tests.
  64   explicit SiteEngagementScore(base::Clock* clock);
  65
  66   // Determine the score, accounting for any decay.
  67   double DecayedScore() const;
  68
  69   // The clock used to vend times. Enables time travelling in tests. Owned by
  70   // the SiteEngagementService.
  71   base::Clock* clock_;
  72
  73   // |raw_score_| is the score before any decay is applied.
  74   double raw_score_;
  75
  76   // The points added 'today' are tracked to avoid adding more than
  77   // kMaxPointsPerDay on any one day. 'Today' is defined in local time.
  78   double points_added_today_;
  79
  80   // The last time the score was updated for engagement. Used in conjunction
  81   // with |points_added_today_| to avoid adding more than kMaxPointsPerDay on
  82   // any one day.
  83   base::Time last_engagement_time_;
  84
  85   DISALLOW_COPY_AND_ASSIGN(SiteEngagementScore);
  86 };
  87
  88 class SiteEngagementScoreProvider {
  89  public:
  90   // Returns a non-negative integer representing the engagement score of the
  91   // origin for this URL.
  92   virtual int GetScore(const GURL& url) = 0;
  93
  94   // Returns the sum of engagement points awarded to all sites.
  95   virtual int GetTotalEngagementPoints() = 0;
  96 };
  97
  98 // Stores and retrieves the engagement score of an origin.
  99 //
 100 // An engagement score is a positive integer that represents how much a user has
 101 // engaged with an origin - the higher it is, the more engagement the user has
 102 // had with this site recently.
 103 //
 104 // Positive user activity, such as visiting the origin often and adding it to
 105 // the homescreen, will increase the site engagement score. Negative activity,
 106 // such as rejecting permission prompts or not responding to notifications, will
 107 // decrease the site engagement score.
 108 class SiteEngagementService : public KeyedService,
 109                               public SiteEngagementScoreProvider {
 110  public:
 111   static SiteEngagementService* Get(Profile* profile);
 112
 113   // Returns whether or not the SiteEngagementService is enabled.
 114   static bool IsEnabled();
 115
 116   explicit SiteEngagementService(Profile* profile);
 117   ~SiteEngagementService() override;
 118
 119   // Returns a map of all stored origins and their engagement scores.
 120   std::map<GURL, int> GetScoreMap();
 121
 122   // Update the karma score of the origin matching |url| for user navigation.
 123   void HandleNavigation(const GURL& url);
 124
 125   // Overridden from SiteEngagementScoreProvider:
 126   int GetScore(const GURL& url) override;
 127   int GetTotalEngagementPoints() override;
 128
 129  private:
 130   Profile* profile_;
 131
 132   // The clock used to vend times.
 133   base::DefaultClock clock_;
 134
 135   DISALLOW_COPY_AND_ASSIGN(SiteEngagementService);
 136 };
 137
 138 #endif  // CHROME_BROWSER_ENGAGEMENT_SITE_ENGAGEMENT_SERVICE_H_