chromeos/timezone/timezone_resolver.h

   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 #ifndef CHROMEOS_TIMEZONE_TIMEZONE_RESOLVER_H_
   6 #define CHROMEOS_TIMEZONE_TIMEZONE_RESOLVER_H_
   7
   8 #include "base/callback.h"
   9 #include "base/macros.h"
  10 #include "base/threading/thread_checker.h"
  11 #include "chromeos/chromeos_export.h"
  12 #include "net/url_request/url_request_context_getter.h"
  13 #include "url/gurl.h"
  14
  15 class PrefRegistrySimple;
  16 class PrefService;
  17
  18 namespace chromeos {
  19
  20 struct TimeZoneResponseData;
  21
  22 // This class implements periodic timezone synchronization.
  23 class CHROMEOS_EXPORT TimeZoneResolver {
  24  public:
  25   class TimeZoneResolverImpl;
  26
  27   // This callback will be called when new timezone arrives.
  28   using ApplyTimeZoneCallback =
  29       base::Callback<void(const TimeZoneResponseData*)>;
  30
  31   // chromeos::DelayNetworkCall cannot be used directly due to link
  32   // restrictions.
  33   using DelayNetworkCallClosure = base::Callback<void(const base::Closure&)>;
  34
  35   // This is a LocalState preference to store base::Time value of the last
  36   // request. It is used to limit request rate on browser restart.
  37   static const char kLastTimeZoneRefreshTime[];
  38
  39   TimeZoneResolver(scoped_refptr<net::URLRequestContextGetter> context,
  40                    const GURL& url,
  41                    const ApplyTimeZoneCallback& apply_timezone,
  42                    const DelayNetworkCallClosure& delay_network_call,
  43                    PrefService* local_state);
  44   ~TimeZoneResolver();
  45
  46   // Starts periodic timezone refresh.
  47   void Start();
  48
  49   // Cancels current request and stops periodic timezone refresh.
  50   void Stop();
  51
  52   // Register prefs to LocalState.
  53   static void RegisterPrefs(PrefRegistrySimple* registry);
  54
  55   scoped_refptr<net::URLRequestContextGetter> context() const {
  56     return context_;
  57   }
  58
  59   DelayNetworkCallClosure delay_network_call() const {
  60     return delay_network_call_;
  61   }
  62
  63   ApplyTimeZoneCallback apply_timezone() const { return apply_timezone_; }
  64
  65   PrefService* local_state() const { return local_state_; }
  66
  67   // Expose internal fuctions for testing.
  68   static int MaxRequestsCountForIntervalForTesting(
  69       const double interval_seconds);
  70   static int IntervalForNextRequestForTesting(const int requests);
  71
  72  private:
  73   scoped_refptr<net::URLRequestContextGetter> context_;
  74   const GURL url_;
  75
  76   const ApplyTimeZoneCallback apply_timezone_;
  77   const DelayNetworkCallClosure delay_network_call_;
  78   PrefService* local_state_;
  79
  80   scoped_ptr<TimeZoneResolverImpl> implementation_;
  81
  82   base::ThreadChecker thread_checker_;
  83
  84   DISALLOW_COPY_AND_ASSIGN(TimeZoneResolver);
  85 };
  86
  87 }  // namespace chromeos
  88
  89 #endif  // CHROMEOS_TIMEZONE_TIMEZONE_RESOLVER_H_