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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_ADAPTER_FETCHER_WIN_H_ | |
6 #define NET_PROXY_DHCP_SCRIPT_ADAPTER_FETCHER_WIN_H_ | |
7 #pragma once | |
8 | |
9 #include "base/memory/ref_counted.h" | |
10 #include "base/memory/scoped_ptr.h" | |
11 #include "base/memory/weak_ptr.h" | |
12 #include "base/string16.h" | |
13 #include "base/threading/non_thread_safe.h" | |
14 #include "base/timer.h" | |
15 #include "net/base/completion_callback.h" | |
16 #include "googleurl/src/gurl.h" | |
17 | |
18 namespace base { | |
19 class MessageLoopProxy; | |
20 } | |
21 | |
22 namespace net { | |
23 | |
24 class ProxyScriptFetcher; | |
25 class URLRequestContext; | |
26 | |
27 // For a given adapter, this class takes care of first doing a DHCP lookup | |
28 // to get the PAC URL, then if there is one, trying to fetch it. | |
29 class DhcpProxyScriptAdapterFetcher | |
30 : public base::SupportsWeakPtr<DhcpProxyScriptAdapterFetcher>, | |
31 public base::NonThreadSafe { | |
32 public: | |
33 // |url_request_context| must outlive DhcpProxyScriptAdapterFetcher. | |
34 explicit DhcpProxyScriptAdapterFetcher( | |
35 URLRequestContext* url_request_context); | |
36 virtual ~DhcpProxyScriptAdapterFetcher(); | |
37 | |
38 // Starts a fetch. On completion (but not cancellation), |callback| | |
39 // will be invoked with the network error indicating success or failure | |
40 // of fetching a DHCP-configured PAC file on this adapter. | |
41 // | |
42 // On completion, results can be obtained via |GetPacScript()|, |GetPacURL()|. | |
43 // | |
44 // You may only call Fetch() once on a given instance of | |
45 // DhcpProxyScriptAdapterFetcher. | |
46 virtual void Fetch(const std::string& adapter_name, | |
47 CompletionCallback* callback); | |
48 | |
49 // Cancels the fetch on this adapter. | |
50 virtual void Cancel(); | |
51 | |
52 // Returns true if in the FINISH state (not CANCEL). | |
53 virtual bool DidFinish() const; | |
54 | |
55 // Returns the network error indicating the result of the fetch. Will | |
56 // return IO_PENDING until the fetch is complete or cancelled. This is | |
57 // the same network error passed to the |callback| provided to |Fetch()|. | |
58 virtual int GetResult() const; | |
59 | |
60 // Returns the contents of the PAC file retrieved. Only valid if | |
61 // |IsComplete()| is true. Returns the empty string if |GetResult()| | |
62 // returns anything other than OK. | |
63 virtual string16 GetPacScript() const; | |
64 | |
65 // Returns the PAC URL retrieved from DHCP. Only guaranteed to be | |
66 // valid if |IsComplete()| is true. Returns an empty URL if no URL was | |
67 // configured in DHCP. May return a valid URL even if |result()| does | |
68 // not return OK (this would indicate that we found a URL configured in | |
69 // DHCP but failed to download it). | |
70 virtual GURL GetPacURL() const; | |
71 | |
72 // Returns the PAC URL configured in DHCP for the given |adapter_name|, or | |
73 // the empty string if none is configured. | |
74 // | |
75 // This function executes synchronously due to limitations of the Windows | |
76 // DHCP client API. | |
77 static std::string GetPacURLFromDhcp(const std::string& adapter_name); | |
78 | |
79 protected: | |
80 // This inner class is used to encapsulate the worker thread, which has | |
81 // only a weak reference back to the main object, so that the main object | |
82 // can be destroyed before the thread ends. This also keeps the main | |
83 // object completely thread safe and allows it to be non-refcounted. | |
84 class WorkerThread : public base::RefCountedThreadSafe<WorkerThread> { | |
85 public: | |
86 // Creates and initializes (but does not start) the worker thread. | |
87 explicit WorkerThread( | |
88 const base::WeakPtr<DhcpProxyScriptAdapterFetcher>& owner); | |
89 virtual ~WorkerThread(); | |
90 | |
91 // Starts the worker thread, fetching information for |adapter_name| using | |
92 // |get_pac_from_url_func|. | |
93 void Start(const std::string& adapter_name); | |
94 | |
95 protected: | |
96 // Virtual method introduced to allow unit testing. | |
97 virtual std::string ImplGetPacURLFromDhcp(const std::string& adapter_name); | |
98 | |
99 private: | |
100 // This is the method that runs on the worker thread. | |
101 void ThreadFunc(const std::string& adapter_name); | |
102 | |
103 // Callback for the above; this executes back on the main thread, | |
104 // not the worker thread. | |
105 void OnThreadDone(const std::string& url); | |
106 | |
107 // All work except ThreadFunc and (sometimes) destruction should occur | |
108 // on the thread that constructs the object. | |
109 base::ThreadChecker thread_checker_; | |
110 | |
111 // May only be accessed on the thread that constructs the object. | |
112 base::WeakPtr<DhcpProxyScriptAdapterFetcher> owner_; | |
113 | |
114 // Used by worker thread to post a message back to the original | |
115 // thread. Fine to use a proxy since in the case where the original | |
116 // thread has gone away, that would mean the |owner_| object is gone | |
117 // anyway, so there is nobody to receive the result. | |
118 scoped_refptr<base::MessageLoopProxy> origin_loop_; | |
119 | |
120 DISALLOW_COPY_AND_ASSIGN(WorkerThread); | |
121 }; | |
122 | |
123 // Event/state transition handlers | |
124 void OnQueryDhcpDone(const std::string& url); | |
125 void OnTimeout(); | |
126 void OnFetcherDone(int result); | |
127 void TransitionToFinish(); | |
128 | |
129 // Virtual methods introduced to allow unit testing. | |
130 virtual ProxyScriptFetcher* ImplCreateScriptFetcher(); | |
131 virtual WorkerThread* ImplCreateWorkerThread( | |
132 const base::WeakPtr<DhcpProxyScriptAdapterFetcher>& owner); | |
133 virtual base::TimeDelta ImplGetTimeout() const; | |
134 | |
135 // This is the state machine for fetching from a given adapter. | |
136 // | |
137 // The state machine goes from START->WAIT_DHCP when it starts | |
138 // a worker thread to fetch the PAC URL from DHCP. | |
139 // | |
140 // In state WAIT_DHCP, if the DHCP query finishes and has no URL, it | |
141 // moves to state FINISH. If there is a URL, it starts a | |
142 // ProxyScriptFetcher to fetch it and moves to state WAIT_URL. | |
143 // | |
144 // It goes from WAIT_URL->FINISH when the ProxyScriptFetcher completes. | |
145 // | |
146 // In state FINISH, completion is indicated to the outer class, with | |
147 // the results of the fetch if a PAC script was successfully fetched. | |
148 // | |
149 // In state WAIT_DHCP, our timeout occurring can push us to FINISH. | |
150 // | |
151 // In any state except FINISH, a call to Cancel() will move to state | |
152 // CANCEL and cause all outstanding work to be cancelled or its | |
153 // results ignored when available. | |
154 enum State { | |
155 STATE_START, | |
156 STATE_WAIT_DHCP, | |
157 STATE_WAIT_URL, | |
158 STATE_FINISH, | |
159 STATE_CANCEL, | |
160 }; | |
161 | |
162 // Current state of this state machine. | |
163 State state_; | |
164 | |
165 // A network error indicating result of operation. | |
166 int result_; | |
167 | |
168 // Empty string or the PAC script downloaded. | |
169 string16 pac_script_; | |
170 | |
171 // Empty URL or the PAC URL configured in DHCP. | |
172 GURL pac_url_; | |
173 | |
174 // Callback to let our client know we're done. Invalid in states | |
175 // START, FINISH and CANCEL. | |
176 CompletionCallback* callback_; | |
177 | |
178 // Container for our worker thread. NULL if not currently running. | |
179 scoped_refptr<WorkerThread> worker_thread_; | |
180 | |
181 // Fetcher to retrieve PAC files once URL is known. | |
182 scoped_ptr<ProxyScriptFetcher> script_fetcher_; | |
183 | |
184 // Callback from the script fetcher. | |
185 CompletionCallbackImpl<DhcpProxyScriptAdapterFetcher> | |
186 script_fetcher_callback_; | |
187 | |
188 // Implements a timeout on the call to the Win32 DHCP API. | |
189 base::OneShotTimer<DhcpProxyScriptAdapterFetcher> wait_timer_; | |
190 | |
191 scoped_refptr<URLRequestContext> url_request_context_; | |
192 | |
193 DISALLOW_IMPLICIT_CONSTRUCTORS(DhcpProxyScriptAdapterFetcher); | |
194 }; | |
195 | |
196 } // namespace net | |
197 | |
198 #endif // NET_PROXY_DHCP_SCRIPT_ADAPTER_FETCHER_WIN_H_ | |
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