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_PROXY_SCRIPT_ADAPTER_FETCHER_WIN_H_ 6 #define NET_PROXY_DHCP_PROXY_SCRIPT_ADAPTER_FETCHER_WIN_H_ 7 8 #include <string> 9 10 #include "base/memory/ref_counted.h" 11 #include "base/memory/scoped_ptr.h" 12 #include "base/memory/weak_ptr.h" 13 #include "base/strings/string16.h" 14 #include "base/threading/non_thread_safe.h" 15 #include "base/timer/timer.h" 16 #include "net/base/completion_callback.h" 17 #include "net/base/net_export.h" 18 #include "url/gurl.h" 19 20 namespace base { 21 class TaskRunner; 22 } 23 24 namespace net { 25 26 class ProxyScriptFetcher; 27 class URLRequestContext; 28 29 // For a given adapter, this class takes care of first doing a DHCP lookup 30 // to get the PAC URL, then if there is one, trying to fetch it. 31 class NET_EXPORT_PRIVATE DhcpProxyScriptAdapterFetcher 32 : public base::SupportsWeakPtr<DhcpProxyScriptAdapterFetcher>, 33 NON_EXPORTED_BASE(public base::NonThreadSafe) { 34 public: 35 // |url_request_context| must outlive DhcpProxyScriptAdapterFetcher. 36 // |task_runner| will be used to post tasks to a thread. 37 DhcpProxyScriptAdapterFetcher(URLRequestContext* url_request_context, 38 scoped_refptr<base::TaskRunner> task_runner); 39 virtual ~DhcpProxyScriptAdapterFetcher(); 40 41 // Starts a fetch. On completion (but not cancellation), |callback| 42 // will be invoked with the network error indicating success or failure 43 // of fetching a DHCP-configured PAC file on this adapter. 44 // 45 // On completion, results can be obtained via |GetPacScript()|, |GetPacURL()|. 46 // 47 // You may only call Fetch() once on a given instance of 48 // DhcpProxyScriptAdapterFetcher. 49 virtual void Fetch(const std::string& adapter_name, 50 const net::CompletionCallback& callback); 51 52 // Cancels the fetch on this adapter. 53 virtual void Cancel(); 54 55 // Returns true if in the FINISH state (not CANCEL). 56 virtual bool DidFinish() const; 57 58 // Returns the network error indicating the result of the fetch. Will 59 // return IO_PENDING until the fetch is complete or cancelled. This is 60 // the same network error passed to the |callback| provided to |Fetch()|. 61 virtual int GetResult() const; 62 63 // Returns the contents of the PAC file retrieved. Only valid if 64 // |IsComplete()| is true. Returns the empty string if |GetResult()| 65 // returns anything other than OK. 66 virtual base::string16 GetPacScript() const; 67 68 // Returns the PAC URL retrieved from DHCP. Only guaranteed to be 69 // valid if |IsComplete()| is true. Returns an empty URL if no URL was 70 // configured in DHCP. May return a valid URL even if |result()| does 71 // not return OK (this would indicate that we found a URL configured in 72 // DHCP but failed to download it). 73 virtual GURL GetPacURL() const; 74 75 // Returns the PAC URL configured in DHCP for the given |adapter_name|, or 76 // the empty string if none is configured. 77 // 78 // This function executes synchronously due to limitations of the Windows 79 // DHCP client API. 80 static std::string GetPacURLFromDhcp(const std::string& adapter_name); 81 82 // Sanitizes a string returned via the DHCP API. 83 static std::string SanitizeDhcpApiString(const char* data, 84 size_t count_bytes); 85 86 protected: 87 // This is the state machine for fetching from a given adapter. 88 // 89 // The state machine goes from START->WAIT_DHCP when it starts 90 // a worker thread to fetch the PAC URL from DHCP. 91 // 92 // In state WAIT_DHCP, if the DHCP query finishes and has no URL, it 93 // moves to state FINISH. If there is a URL, it starts a 94 // ProxyScriptFetcher to fetch it and moves to state WAIT_URL. 95 // 96 // It goes from WAIT_URL->FINISH when the ProxyScriptFetcher completes. 97 // 98 // In state FINISH, completion is indicated to the outer class, with 99 // the results of the fetch if a PAC script was successfully fetched. 100 // 101 // In state WAIT_DHCP, our timeout occurring can push us to FINISH. 102 // 103 // In any state except FINISH, a call to Cancel() will move to state 104 // CANCEL and cause all outstanding work to be cancelled or its 105 // results ignored when available. 106 enum State { 107 STATE_START, 108 STATE_WAIT_DHCP, 109 STATE_WAIT_URL, 110 STATE_FINISH, 111 STATE_CANCEL, 112 }; 113 114 State state() const; 115 116 // This inner class encapsulates work done on a worker pool thread. 117 // By using a separate object, we can keep the main object completely 118 // thread safe and let it be non-refcounted. 119 class NET_EXPORT_PRIVATE DhcpQuery 120 : public base::RefCountedThreadSafe<DhcpQuery> { 121 public: 122 DhcpQuery(); 123 virtual ~DhcpQuery(); 124 125 // This method should run on a worker pool thread, via PostTaskAndReply. 126 // After it has run, the |url()| method on this object will return the 127 // URL retrieved. 128 void GetPacURLForAdapter(const std::string& adapter_name); 129 130 // Returns the URL retrieved for the given adapter, once the task has run. 131 const std::string& url() const; 132 133 protected: 134 // Virtual method introduced to allow unit testing. 135 virtual std::string ImplGetPacURLFromDhcp(const std::string& adapter_name); 136 137 private: 138 // The URL retrieved for the given adapter. 139 std::string url_; 140 141 DISALLOW_COPY_AND_ASSIGN(DhcpQuery); 142 }; 143 144 // Virtual methods introduced to allow unit testing. 145 virtual ProxyScriptFetcher* ImplCreateScriptFetcher(); 146 virtual DhcpQuery* ImplCreateDhcpQuery(); 147 virtual base::TimeDelta ImplGetTimeout() const; 148 149 private: 150 // Event/state transition handlers 151 void OnDhcpQueryDone(scoped_refptr<DhcpQuery> dhcp_query); 152 void OnTimeout(); 153 void OnFetcherDone(int result); 154 void TransitionToFinish(); 155 156 // TaskRunner for posting tasks to a worker thread. 157 scoped_refptr<base::TaskRunner> task_runner_; 158 159 // Current state of this state machine. 160 State state_; 161 162 // A network error indicating result of operation. 163 int result_; 164 165 // Empty string or the PAC script downloaded. 166 base::string16 pac_script_; 167 168 // Empty URL or the PAC URL configured in DHCP. 169 GURL pac_url_; 170 171 // Callback to let our client know we're done. Invalid in states 172 // START, FINISH and CANCEL. 173 net::CompletionCallback callback_; 174 175 // Fetcher to retrieve PAC files once URL is known. 176 scoped_ptr<ProxyScriptFetcher> script_fetcher_; 177 178 // Implements a timeout on the call to the Win32 DHCP API. 179 base::OneShotTimer<DhcpProxyScriptAdapterFetcher> wait_timer_; 180 181 URLRequestContext* const url_request_context_; 182 183 DISALLOW_IMPLICIT_CONSTRUCTORS(DhcpProxyScriptAdapterFetcher); 184 }; 185 186 } // namespace net 187 188 #endif // NET_PROXY_DHCP_PROXY_SCRIPT_ADAPTER_FETCHER_WIN_H_ 189
