1// Copyright (c) 2013 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_METRICS_VARIATIONS_VARIATIONS_REQUEST_SCHEDULER_H_
6#define CHROME_BROWSER_METRICS_VARIATIONS_VARIATIONS_REQUEST_SCHEDULER_H_
7
8#include "base/bind.h"
9#include "base/gtest_prod_util.h"
10#include "base/time/time.h"
11#include "base/timer/timer.h"
12
13class PrefService;
14
15namespace chrome_variations {
16
17// A helper class that makes VariationsService requests at the correct times.
18class VariationsRequestScheduler {
19 public:
20  virtual ~VariationsRequestScheduler();
21
22  // Starts the task. This can be a repeated event or a one-off.
23  virtual void Start();
24
25  // Resets the scheduler if it is currently on a timer.
26  virtual void Reset();
27
28  // Schedules a fetch shortly, for example to re-try the initial request which
29  // may have failed.
30  void ScheduleFetchShortly();
31
32  // Called when the application has been foregrounded. This may fetch a new
33  // seed.
34  virtual void OnAppEnterForeground();
35
36  // Factory method for this class.
37  static VariationsRequestScheduler* Create(const base::Closure& task,
38                                            PrefService* local_state);
39
40 protected:
41  // |task| is the closure to call when the scheduler deems ready.
42  explicit VariationsRequestScheduler(const base::Closure& task);
43
44  // Getter for derived classes.
45  base::Closure task() const;
46
47 private:
48  FRIEND_TEST_ALL_PREFIXES(VariationsRequestSchedulerTest,
49                           ScheduleFetchShortly);
50
51  // The task scheduled by this class.
52  base::Closure task_;
53
54  // The timer used to repeatedly ping the server. Keep this as an instance
55  // member so if VariationsRequestScheduler goes out of scope, the timer is
56  // automatically canceled.
57  base::RepeatingTimer<VariationsRequestScheduler> timer_;
58
59  // A one-shot timer used for scheduling out-of-band fetches.
60  base::OneShotTimer<VariationsRequestScheduler> one_shot_timer_;
61
62  DISALLOW_COPY_AND_ASSIGN(VariationsRequestScheduler);
63};
64
65}  // namespace chrome_variations
66
67#endif  // CHROME_BROWSER_METRICS_VARIATIONS_VARIATIONS_REQUEST_SCHEDULER_H_
68