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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_DHCP_SCRIPT_FETCHER_FACTORY_H_ | |
6 #define NET_PROXY_DHCP_SCRIPT_FETCHER_FACTORY_H_ | |
7 #pragma once | |
8 | |
9 #include "base/basictypes.h" | |
10 #include "base/memory/singleton.h" | |
11 #include "net/base/completion_callback.h" | |
12 #include "net/url_request/url_request_context.h" | |
13 | |
14 namespace net { | |
15 | |
16 class DhcpProxyScriptFetcher; | |
17 | |
18 // Factory object (non-singleton) for creating the appropriate concrete base | |
eroman
2011/05/13 05:03:32
What do you mean by non-singleton? This is in fact
Jói
2011/05/13 20:19:09
I commented that way because you use it via static
| |
19 // class of DhcpProxyScriptFetcher for your operating system and settings. | |
20 // | |
21 // You might think we could just implement a DHCP client at the protocol | |
22 // level and have cross-platform support for retrieving PAC configuration | |
23 // from DHCP, but unfortunately the DHCP protocol assumes there is a single | |
24 // client per machine (specifically per network interface card), and there | |
25 // is an implicit state machine between the client and server, so adding a | |
26 // second client to the machine would not be advisable (see e.g. some | |
27 // discussion of what can happen at this URL: | |
28 // http://www.net.princeton.edu/multi-dhcp-one-interface-handling.html). | |
29 // | |
30 // Therefore, we have platform-specific implementations, and so we use | |
31 // this factory to select the right one. | |
32 class DhcpProxyScriptFetcherFactory { | |
33 public: | |
34 // Ownership is transferred to the caller. url_request_context must be valid | |
35 // and its lifetime must exceed that of the returned DhcpProxyScriptFetcher. | |
36 // | |
37 // Note that while a request is in progress, the fetcher may be holding a | |
38 // reference to |url_request_context|. Be careful not to create cycles | |
39 // between the fetcher and the context; you can break such cycles by calling | |
40 // Cancel(). | |
41 static DhcpProxyScriptFetcher* Create(URLRequestContext* url_request_context); | |
42 | |
43 // Attempts to enable/disable the DHCP WPAD feature. Does nothing | |
44 // if |IsSupported()| returns false. | |
45 // | |
46 // The feature is disabled by default, for now. | |
47 static void SetEnabled(bool enabled); | |
48 | |
49 // Returns true if the DHCP WPAD feature is enabled. Always returns | |
50 // false if |IsSupported()| is false. | |
51 static bool IsEnabled(); | |
52 | |
53 // Returns true if the DHCP WPAD feature is supported on the current | |
54 // operating system. | |
55 static bool IsSupported(); | |
56 | |
57 protected: | |
58 static bool feature_enabled_; | |
59 | |
60 DISALLOW_IMPLICIT_CONSTRUCTORS(DhcpProxyScriptFetcherFactory); | |
61 }; | |
62 | |
63 } // namespace net | |
64 | |
65 #endif // NET_PROXY_DHCP_SCRIPT_FETCHER_FACTORY_H_ | |
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