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