chrome/browser/chromeos/session_length_limiter.h

   1 // Copyright (c) 2012 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_CHROMEOS_SESSION_LENGTH_LIMITER_H_
   6 #define CHROME_BROWSER_CHROMEOS_SESSION_LENGTH_LIMITER_H_
   7
   8 #include "base/basictypes.h"
   9 #include "base/compiler_specific.h"
  10 #include "base/memory/scoped_ptr.h"
  11 #include "base/prefs/pref_change_registrar.h"
  12 #include "base/threading/thread_checker.h"
  13 #include "base/time/time.h"
  14 #include "base/timer/timer.h"
  15 #include "ui/base/user_activity/user_activity_observer.h"
  16
  17 class PrefService;
  18 class PrefRegistrySimple;
  19
  20 namespace chromeos {
  21
  22 // Enforces a session length limit by terminating the session when the limit is
  23 // reached.
  24 class SessionLengthLimiter : public ui::UserActivityObserver {
  25  public:
  26   class Delegate {
  27    public:
  28     virtual ~Delegate();
  29
  30     virtual const base::TimeTicks GetCurrentTime() const = 0;
  31     virtual void StopSession() = 0;
  32   };
  33
  34   // Registers preferences.
  35   static void RegisterPrefs(PrefRegistrySimple* registry);
  36
  37   SessionLengthLimiter(Delegate* delegate, bool browser_restarted);
  38   ~SessionLengthLimiter() override;
  39
  40   // ui::UserActivityObserver:
  41   void OnUserActivity(const ui::Event* event) override;
  42
  43  private:
  44   // Attempt to restore the session start time and the flag indicating user
  45   // activity from local state. Return |true| if the restore is successful.
  46   bool RestoreStateAfterCrash();
  47
  48   // Update the session start time if possible:
  49   // * If instructed to wait for initial user activity, the session start time
  50   //   advances every time this method is called as long as no user activity has
  51   //   occurred yet. The time is not persisted in local state.
  52   // * If instructed not to wait for initial user activity, the session start
  53   //   time is set and persisted in local state the first time this method is
  54   //   called.
  55   // The pref indicating whether to wait for initial user activity may change at
  56   // any time, switching between the two behaviors.
  57   void UpdateSessionStartTime();
  58
  59   void UpdateLimit();
  60
  61   base::ThreadChecker thread_checker_;
  62
  63   scoped_ptr<Delegate> delegate_;
  64   PrefChangeRegistrar pref_change_registrar_;
  65
  66   scoped_ptr<base::OneShotTimer<SessionLengthLimiter::Delegate> > timer_;
  67   base::TimeTicks session_start_time_;
  68   bool user_activity_seen_;
  69
  70   DISALLOW_COPY_AND_ASSIGN(SessionLengthLimiter);
  71 };
  72
  73 }  // namespace chromeos
  74
  75 #endif  // CHROME_BROWSER_CHROMEOS_SESSION_LENGTH_LIMITER_H_