net/base/network_change_notifier_win.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 NET_BASE_NETWORK_CHANGE_NOTIFIER_WIN_H_
   6 #define NET_BASE_NETWORK_CHANGE_NOTIFIER_WIN_H_
   7
   8 #include <windows.h>
   9
  10 #include "base/basictypes.h"
  11 #include "base/compiler_specific.h"
  12 #include "base/memory/scoped_ptr.h"
  13 #include "base/memory/weak_ptr.h"
  14 #include "base/threading/non_thread_safe.h"
  15 #include "base/timer/timer.h"
  16 #include "base/win/object_watcher.h"
  17 #include "net/base/net_export.h"
  18 #include "net/base/network_change_notifier.h"
  19
  20 namespace net {
  21
  22 // NetworkChangeNotifierWin inherits from NonThreadSafe, as all its internal
  23 // notification code must be called on the thread it is created and destroyed
  24 // on.  All the NetworkChangeNotifier methods it implements are threadsafe.
  25 class NET_EXPORT_PRIVATE NetworkChangeNotifierWin
  26     : public NetworkChangeNotifier,
  27       public base::win::ObjectWatcher::Delegate,
  28       NON_EXPORTED_BASE(public base::NonThreadSafe) {
  29  public:
  30   NetworkChangeNotifierWin();
  31
  32   // Begins listening for a single subsequent address change.  If it fails to
  33   // start watching, it retries on a timer.  Must be called only once, on the
  34   // thread |this| was created on.  This cannot be called in the constructor, as
  35   // WatchForAddressChangeInternal is mocked out in unit tests.
  36   // TODO(mmenke): Consider making this function a part of the
  37   //               NetworkChangeNotifier interface, so other subclasses can be
  38   //               unit tested in similar fashion, as needed.
  39   void WatchForAddressChange();
  40
  41  protected:
  42   virtual ~NetworkChangeNotifierWin();
  43
  44   // For unit tests only.
  45   bool is_watching() { return is_watching_; }
  46   void set_is_watching(bool is_watching) { is_watching_ = is_watching; }
  47   int sequential_failures() { return sequential_failures_; }
  48
  49  private:
  50   class DnsConfigServiceThread;
  51   friend class NetworkChangeNotifierWinTest;
  52
  53   // NetworkChangeNotifier methods:
  54   virtual ConnectionType GetCurrentConnectionType() const OVERRIDE;
  55
  56   // ObjectWatcher::Delegate methods:
  57   // Must only be called on the thread |this| was created on.
  58   virtual void OnObjectSignaled(HANDLE object) OVERRIDE;
  59
  60   // Does the actual work to determine the current connection type.
  61   // It is not thread safe, see crbug.com/324913.
  62   virtual ConnectionType RecomputeCurrentConnectionType() const;
  63
  64   void SetCurrentConnectionType(ConnectionType connection_type);
  65
  66   // Notifies IP address change observers of a change immediately, and notifies
  67   // network state change observers on a delay.  Must only be called on the
  68   // thread |this| was created on.
  69   void NotifyObservers();
  70
  71   // Forwards connection type notifications to parent class.
  72   void NotifyParentOfConnectionTypeChange();
  73
  74   // Tries to start listening for a single subsequent address change.  Returns
  75   // false on failure.  The caller is responsible for updating |is_watching_|.
  76   // Virtual for unit tests.  Must only be called on the thread |this| was
  77   // created on.
  78   virtual bool WatchForAddressChangeInternal();
  79
  80   static NetworkChangeCalculatorParams NetworkChangeCalculatorParamsWin();
  81
  82   // All member variables may only be accessed on the thread |this| was created
  83   // on.
  84
  85   // False when not currently watching for network change events.  This only
  86   // happens on initialization and when WatchForAddressChangeInternal fails and
  87   // there is a pending task to try again.  Needed for safe cleanup.
  88   bool is_watching_;
  89
  90   base::win::ObjectWatcher addr_watcher_;
  91   OVERLAPPED addr_overlapped_;
  92
  93   base::OneShotTimer<NetworkChangeNotifierWin> timer_;
  94
  95   // Number of times WatchForAddressChange has failed in a row.
  96   int sequential_failures_;
  97
  98   // Used for calling WatchForAddressChange again on failure.
  99   base::WeakPtrFactory<NetworkChangeNotifierWin> weak_factory_;
 100
 101   // Thread on which we can run DnsConfigService.
 102   scoped_ptr<DnsConfigServiceThread> dns_config_service_thread_;
 103
 104   mutable base::Lock last_computed_connection_type_lock_;
 105   ConnectionType last_computed_connection_type_;
 106
 107   // Result of IsOffline() when NotifyObserversOfConnectionTypeChange()
 108   // was last called.
 109   bool last_announced_offline_;
 110   // Number of times polled to check if still offline.
 111   int offline_polls_;
 112
 113   DISALLOW_COPY_AND_ASSIGN(NetworkChangeNotifierWin);
 114 };
 115
 116 }  // namespace net
 117
 118 #endif  // NET_BASE_NETWORK_CHANGE_NOTIFIER_WIN_H_