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
20namespace 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.
25class 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  // Thread on which we can run DnsConfigService.
99  scoped_ptr<DnsConfigServiceThread> dns_config_service_thread_;
100
101  mutable base::Lock last_computed_connection_type_lock_;
102  ConnectionType last_computed_connection_type_;
103
104  // Result of IsOffline() when NotifyObserversOfConnectionTypeChange()
105  // was last called.
106  bool last_announced_offline_;
107  // Number of times polled to check if still offline.
108  int offline_polls_;
109
110  // Used for calling WatchForAddressChange again on failure.
111  base::WeakPtrFactory<NetworkChangeNotifierWin> weak_factory_;
112
113  DISALLOW_COPY_AND_ASSIGN(NetworkChangeNotifierWin);
114};
115
116}  // namespace net
117
118#endif  // NET_BASE_NETWORK_CHANGE_NOTIFIER_WIN_H_
119