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