components/google/core/browser/google_url_tracker.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 COMPONENTS_GOOGLE_CORE_BROWSER_GOOGLE_URL_TRACKER_H_
   6 #define COMPONENTS_GOOGLE_CORE_BROWSER_GOOGLE_URL_TRACKER_H_
   7
   8 #include "base/callback_forward.h"
   9 #include "base/callback_list.h"
  10 #include "base/memory/scoped_ptr.h"
  11 #include "base/memory/weak_ptr.h"
  12 #include "components/google/core/browser/google_url_tracker_client.h"
  13 #include "components/keyed_service/core/keyed_service.h"
  14 #include "net/base/network_change_notifier.h"
  15 #include "net/url_request/url_fetcher.h"
  16 #include "net/url_request/url_fetcher_delegate.h"
  17 #include "url/gurl.h"
  18
  19 class PrefService;
  20
  21 namespace infobars {
  22 class InfoBar;
  23 }
  24
  25 namespace user_prefs {
  26 class PrefRegistrySyncable;
  27 }
  28
  29 // This object is responsible for checking the Google URL once per network
  30 // change.  The current value is saved to prefs.
  31 //
  32 // Most consumers should only call google_url().  Consumers who need to be
  33 // notified when things change should register a callback that provides the
  34 // original and updated values via RegisterCallback().
  35 //
  36 // To protect users' privacy and reduce server load, no updates will be
  37 // performed (ever) unless at least one consumer registers interest by calling
  38 // RequestServerCheck().
  39 class GoogleURLTracker
  40     : public net::URLFetcherDelegate,
  41       public net::NetworkChangeNotifier::NetworkChangeObserver,
  42       public KeyedService {
  43  public:
  44   // Callback that is called when the Google URL is updated. The arguments are
  45   // the old and new URLs.
  46   typedef base::Callback<void()> OnGoogleURLUpdatedCallback;
  47   typedef base::CallbackList<void()> CallbackList;
  48   typedef CallbackList::Subscription Subscription;
  49
  50   // The constructor does different things depending on which of these values
  51   // you pass it.  Hopefully these are self-explanatory.
  52   enum Mode {
  53     NORMAL_MODE,
  54     UNIT_TEST_MODE,
  55   };
  56
  57   static const char kDefaultGoogleHomepage[];
  58
  59   // Only the GoogleURLTrackerFactory and tests should call this.
  60   GoogleURLTracker(scoped_ptr<GoogleURLTrackerClient> client, Mode mode);
  61
  62   ~GoogleURLTracker() override;
  63
  64   // Register user preferences for GoogleURLTracker.
  65   static void RegisterProfilePrefs(user_prefs::PrefRegistrySyncable* registry);
  66
  67
  68   // Returns the current Google homepage URL.
  69   const GURL& google_url() const { return google_url_; }
  70
  71   // Requests that the tracker perform a server check to update the Google URL
  72   // as necessary.  If |force| is false, this will happen at most once per
  73   // network change, not sooner than five seconds after startup (checks
  74   // requested before that time will occur then; checks requested afterwards
  75   // will occur immediately, if no other checks have been made during this run).
  76   // If |force| is true, and the tracker has already performed any requested
  77   // check, it will check again.
  78   void RequestServerCheck(bool force);
  79
  80   scoped_ptr<Subscription> RegisterCallback(
  81       const OnGoogleURLUpdatedCallback& cb);
  82
  83  private:
  84   friend class GoogleURLTrackerTest;
  85   friend class SyncTest;
  86
  87   static const char kSearchDomainCheckURL[];
  88
  89   // net::URLFetcherDelegate:
  90   void OnURLFetchComplete(const net::URLFetcher* source) override;
  91
  92   // NetworkChangeNotifier::IPAddressObserver:
  93   void OnNetworkChanged(
  94       net::NetworkChangeNotifier::ConnectionType type) override;
  95
  96   // KeyedService:
  97   void Shutdown() override;
  98
  99   // Sets |need_to_fetch_| and attempts to start a fetch.
 100   void SetNeedToFetch();
 101
 102   // Called when the five second startup sleep has finished.  Runs any pending
 103   // fetch.
 104   void FinishSleep();
 105
 106   // Starts the fetch of the up-to-date Google URL if we actually want to fetch
 107   // it and can currently do so.
 108   void StartFetchIfDesirable();
 109
 110   CallbackList callback_list_;
 111
 112   scoped_ptr<GoogleURLTrackerClient> client_;
 113
 114   GURL google_url_;
 115   scoped_ptr<net::URLFetcher> fetcher_;
 116   int fetcher_id_;
 117   bool in_startup_sleep_;  // True if we're in the five-second "no fetching"
 118                            // period that begins at browser start.
 119   bool already_fetched_;   // True if we've already fetched a URL once this run;
 120                            // we won't fetch again until after a restart.
 121   bool need_to_fetch_;     // True if a consumer actually wants us to fetch an
 122                            // updated URL.  If this is never set, we won't
 123                            // bother to fetch anything.
 124                            // Consumers should register a callback via
 125                            // RegisterCallback().
 126   base::WeakPtrFactory<GoogleURLTracker> weak_ptr_factory_;
 127
 128   DISALLOW_COPY_AND_ASSIGN(GoogleURLTracker);
 129 };
 130
 131 #endif  // COMPONENTS_GOOGLE_CORE_BROWSER_GOOGLE_URL_TRACKER_H_