chrome/browser/engagement/site_engagement_service.cc

   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 #include "chrome/browser/engagement/site_engagement_service.h"
   6
   7 #include <algorithm>
   8 #include <cmath>
   9
  10 #include "base/command_line.h"
  11 #include "base/time/clock.h"
  12 #include "chrome/browser/engagement/site_engagement_helper.h"
  13 #include "chrome/browser/engagement/site_engagement_service_factory.h"
  14 #include "chrome/browser/profiles/profile.h"
  15 #include "chrome/common/chrome_switches.h"
  16 #include "url/gurl.h"
  17
  18 const double SiteEngagementScore::kMaxPoints = 100;
  19 const double SiteEngagementScore::kMaxPointsPerDay = 5;
  20 const double SiteEngagementScore::kNavigationPoints = 1;
  21 const int SiteEngagementScore::kDecayPeriodInDays = 7;
  22 const double SiteEngagementScore::kDecayPoints = 5;
  23
  24 SiteEngagementScore::SiteEngagementScore() : SiteEngagementScore(nullptr) {
  25 }
  26
  27 SiteEngagementScore::SiteEngagementScore(base::Clock* clock)
  28     : clock_(clock), raw_score_(0), added_today_(0), last_engagement_() {
  29 }
  30
  31 SiteEngagementScore::~SiteEngagementScore() {
  32 }
  33
  34 double SiteEngagementScore::Score() const {
  35   return DecayedScore();
  36 }
  37
  38 void SiteEngagementScore::AddPoints(double points) {
  39   // As the score is about to be updated, commit any decay that has happened
  40   // since the last update.
  41   raw_score_ = DecayedScore();
  42
  43   base::Time now = Now();
  44   if (!last_engagement_.is_null() &&
  45       now.LocalMidnight() != last_engagement_.LocalMidnight()) {
  46     added_today_ = 0;
  47   }
  48
  49   double to_add =
  50       std::min(kMaxPoints - raw_score_, kMaxPointsPerDay - added_today_);
  51   to_add = std::min(to_add, points);
  52
  53   added_today_ += to_add;
  54   raw_score_ += to_add;
  55
  56   last_engagement_ = now;
  57 }
  58
  59 double SiteEngagementScore::DecayedScore() const {
  60   // Note that users can change their clock, so from this system's perspective
  61   // time can go backwards. If that does happen and the system detects that the
  62   // current day is earlier than the last engagement, no decay (or growth) is
  63   // applied.
  64   int days_since_engagement = (Now() - last_engagement_).InDays();
  65   if (days_since_engagement < 0)
  66     return raw_score_;
  67
  68   int periods = days_since_engagement / kDecayPeriodInDays;
  69   double decayed_score = raw_score_ - periods * kDecayPoints;
  70   return std::max(0.0, decayed_score);
  71 }
  72
  73 base::Time SiteEngagementScore::Now() const {
  74   if (clock_)
  75     return clock_->Now();
  76
  77   return base::Time::Now();
  78 }
  79
  80 // static
  81 SiteEngagementService* SiteEngagementService::Get(Profile* profile) {
  82   return SiteEngagementServiceFactory::GetForProfile(profile);
  83 }
  84
  85 // static
  86 bool SiteEngagementService::IsEnabled() {
  87   return base::CommandLine::ForCurrentProcess()->HasSwitch(
  88       switches::kEnableSiteEngagementService);
  89 }
  90
  91 SiteEngagementService::SiteEngagementService(Profile* profile)
  92     : profile_(profile) {
  93 }
  94
  95 SiteEngagementService::~SiteEngagementService() {
  96 }
  97
  98 void SiteEngagementService::HandleNavigation(const GURL& url) {
  99   GURL origin = url.GetOrigin();
 100   scores_[origin].AddPoints(SiteEngagementScore::kNavigationPoints);
 101 }
 102
 103 int SiteEngagementService::GetScore(const GURL& url) {
 104   return scores_[url.GetOrigin()].Score();
 105 }
 106