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_PROXY_DHCP_SCRIPT_FETCHER_FACTORY_H_ 6 #define NET_PROXY_DHCP_SCRIPT_FETCHER_FACTORY_H_ 7 8 #include "base/basictypes.h" 9 #include "base/memory/singleton.h" 10 #include "net/base/completion_callback.h" 11 #include "net/base/net_export.h" 12 13 namespace net { 14 15 class DhcpProxyScriptFetcher; 16 class URLRequestContext; 17 18 // Factory object for creating the appropriate concrete base class of 19 // 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 NET_EXPORT DhcpProxyScriptFetcherFactory { 33 public: 34 // Creates a new factory object with default settings. 35 DhcpProxyScriptFetcherFactory(); 36 37 // Ownership is transferred to the caller. url_request_context must be valid 38 // and its lifetime must exceed that of the returned DhcpProxyScriptFetcher. 39 // 40 // Note that while a request is in progress, the fetcher may be holding a 41 // reference to |url_request_context|. Be careful not to create cycles 42 // between the fetcher and the context; you can break such cycles by calling 43 // Cancel(). 44 DhcpProxyScriptFetcher* Create(URLRequestContext* url_request_context); 45 46 // Attempts to enable/disable the DHCP WPAD feature. Does nothing 47 // if |IsSupported()| returns false. 48 // 49 // The default is |enabled() == true|. 50 void set_enabled(bool enabled); 51 52 // Returns true if the DHCP WPAD feature is enabled. Always returns 53 // false if |IsSupported()| is false. 54 bool enabled() const; 55 56 // Returns true if the DHCP WPAD feature is supported on the current 57 // operating system. 58 static bool IsSupported(); 59 60 private: 61 bool feature_enabled_; 62 63 DISALLOW_COPY_AND_ASSIGN(DhcpProxyScriptFetcherFactory); 64 }; 65 66 } // namespace net 67 68 #endif // NET_PROXY_DHCP_SCRIPT_FETCHER_FACTORY_H_ 69
