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1 // Copyright (c) 2011 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_PROXY_PROXY_CONFIG_SERVICE_WIN_H_
6 #define NET_PROXY_PROXY_CONFIG_SERVICE_WIN_H_
7 
8 #include <windows.h>
9 #include <winhttp.h>
10 
11 #include <vector>
12 
13 #include "base/compiler_specific.h"
14 #include "base/gtest_prod_util.h"
15 #include "base/win/object_watcher.h"
16 #include "net/proxy/polling_proxy_config_service.h"
17 
18 namespace net {
19 
20 // Implementation of ProxyConfigService that retrieves the system proxy
21 // settings.
22 //
23 // It works by calling WinHttpGetIEProxyConfigForCurrentUser() to fetch the
24 // Internet Explorer proxy settings.
25 //
26 // We use two different strategies to notice when the configuration has
27 // changed:
28 //
29 // (1) Watch the internet explorer settings registry keys for changes. When
30 //     one of the registry keys pertaining to proxy settings has changed, we
31 //     call WinHttpGetIEProxyConfigForCurrentUser() again to read the
32 //     configuration's new value.
33 //
34 // (2) Do regular polling every 10 seconds during network activity to see if
35 //     WinHttpGetIEProxyConfigForCurrentUser() returns something different.
36 //
37 // Ideally strategy (1) should be sufficient to pick up all of the changes.
38 // However we still do the regular polling as a precaution in case the
39 // implementation details of  WinHttpGetIEProxyConfigForCurrentUser() ever
40 // change, or in case we got it wrong (and are not checking all possible
41 // registry dependencies).
42 class NET_EXPORT_PRIVATE ProxyConfigServiceWin
43     : public PollingProxyConfigService,
44       public base::win::ObjectWatcher::Delegate {
45  public:
46   ProxyConfigServiceWin();
47   virtual ~ProxyConfigServiceWin();
48 
49   // Overrides a function from PollingProxyConfigService.
50   virtual void AddObserver(Observer* observer) OVERRIDE;
51 
52  private:
53   FRIEND_TEST_ALL_PREFIXES(ProxyConfigServiceWinTest, SetFromIEConfig);
54   class KeyEntry;
55   typedef std::vector<KeyEntry*> KeyEntryList;
56 
57   // Registers change observers on the registry keys relating to proxy settings.
58   void StartWatchingRegistryForChanges();
59 
60   // Creates a new KeyEntry and appends it to |keys_to_watch_|. If the key
61   // fails to be created, it is not appended to the list and we return false.
62   bool AddKeyToWatchList(HKEY rootkey, const wchar_t* subkey);
63 
64   // ObjectWatcher::Delegate methods:
65   // This is called whenever one of the registry keys we are watching change.
66   virtual void OnObjectSignaled(HANDLE object) OVERRIDE;
67 
68   static void GetCurrentProxyConfig(ProxyConfig* config);
69 
70   // Set |config| using the proxy configuration values of |ie_config|.
71   static void SetFromIEConfig(
72       ProxyConfig* config,
73       const WINHTTP_CURRENT_USER_IE_PROXY_CONFIG& ie_config);
74 
75   KeyEntryList keys_to_watch_;
76 };
77 
78 }  // namespace net
79 
80 #endif  // NET_PROXY_PROXY_CONFIG_SERVICE_WIN_H_
81