components/metrics/daily_event.cc

   1 // Copyright 2014 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 "components/metrics/daily_event.h"
   6
   7 #include "base/i18n/time_formatting.h"
   8 #include "base/metrics/histogram.h"
   9 #include "base/prefs/pref_registry_simple.h"
  10 #include "base/prefs/pref_service.h"
  11
  12 namespace metrics {
  13
  14 namespace {
  15
  16 enum IntervalType {
  17   FIRST_RUN,
  18   DAY_ELAPSED,
  19   CLOCK_CHANGED,
  20   NUM_INTERVAL_TYPES
  21 };
  22
  23 void RecordIntervalTypeHistogram(const std::string& histogram_name,
  24                                  IntervalType type) {
  25   base::Histogram::FactoryGet(
  26       histogram_name,
  27       1,
  28       NUM_INTERVAL_TYPES,
  29       NUM_INTERVAL_TYPES + 1,
  30       base::HistogramBase::kUmaTargetedHistogramFlag)->Add(type);
  31 }
  32
  33 }  // namespace
  34
  35 DailyEvent::Observer::Observer() {
  36 }
  37
  38 DailyEvent::Observer::~Observer() {
  39 }
  40
  41 DailyEvent::DailyEvent(PrefService* pref_service,
  42                        const char* pref_name,
  43                        const std::string& histogram_name)
  44     : pref_service_(pref_service),
  45       pref_name_(pref_name),
  46       histogram_name_(histogram_name) {
  47 }
  48
  49 DailyEvent::~DailyEvent() {
  50 }
  51
  52 // static
  53 void DailyEvent::RegisterPref(PrefRegistrySimple* registry,
  54                               const char* pref_name) {
  55   registry->RegisterInt64Pref(pref_name, base::Time().ToInternalValue());
  56 }
  57
  58 void DailyEvent::AddObserver(scoped_ptr<DailyEvent::Observer> observer) {
  59   DVLOG(2) << "DailyEvent observer added.";
  60   DCHECK(last_fired_.is_null());
  61   observers_.push_back(observer.release());
  62 }
  63
  64 void DailyEvent::CheckInterval() {
  65   base::Time now = base::Time::Now();
  66   if (last_fired_.is_null()) {
  67     // The first time we call CheckInterval, we read the time stored in prefs.
  68     last_fired_ = base::Time::FromInternalValue(
  69         pref_service_->GetInt64(pref_name_));
  70     DVLOG(1) << "DailyEvent time loaded: "
  71              << base::TimeFormatShortDateAndTime(last_fired_);
  72     if (last_fired_.is_null()) {
  73       DVLOG(1) << "DailyEvent first run.";
  74       RecordIntervalTypeHistogram(pref_name_, FIRST_RUN);
  75       OnInterval(now);
  76       return;
  77     }
  78   }
  79   int days_elapsed = (now - last_fired_).InDays();
  80   if (days_elapsed >= 1) {
  81     DVLOG(1) << "DailyEvent day elapsed.";
  82     RecordIntervalTypeHistogram(pref_name_, DAY_ELAPSED);
  83     OnInterval(now);
  84   } else if (days_elapsed <= -1) {
  85     // The "last fired" time is more than a day in the future, so the clock
  86     // must have been changed.
  87     DVLOG(1) << "DailyEvent clock change detected.";
  88     RecordIntervalTypeHistogram(pref_name_, CLOCK_CHANGED);
  89     OnInterval(now);
  90   }
  91 }
  92
  93 void DailyEvent::OnInterval(base::Time now) {
  94   DCHECK(!now.is_null());
  95   last_fired_ = now;
  96   pref_service_->SetInt64(pref_name_, last_fired_.ToInternalValue());
  97
  98   // Notify all observers
  99   for (ScopedVector<DailyEvent::Observer>::iterator it = observers_.begin();
 100        it != observers_.end();
 101        ++it) {
 102     (*it)->OnDailyEvent();
 103   }
 104 }
 105
 106 }  // namespace metrics