1 //
2 // Copyright (C) 2010 The Android Open Source Project
3 //
4 // Licensed under the Apache License, Version 2.0 (the "License");
5 // you may not use this file except in compliance with the License.
6 // You may obtain a copy of the License at
7 //
8 //      http://www.apache.org/licenses/LICENSE-2.0
9 //
10 // Unless required by applicable law or agreed to in writing, software
11 // distributed under the License is distributed on an "AS IS" BASIS,
12 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 // See the License for the specific language governing permissions and
14 // limitations under the License.
15 //
16 
17 #ifndef UPDATE_ENGINE_PROXY_RESOLVER_H_
18 #define UPDATE_ENGINE_PROXY_RESOLVER_H_
19 
20 #include <deque>
21 #include <string>
22 
23 #include <base/logging.h>
24 #include <brillo/message_loops/message_loop.h>
25 
26 #include "update_engine/common/utils.h"
27 
28 namespace chromeos_update_engine {
29 
30 extern const char kNoProxy[];
31 
32 // Callback for a call to GetProxiesForUrl().
33 // Resultant proxies are in |out_proxy|. Each will be in one of the
34 // following forms:
35 // http://<host>[:<port>] - HTTP proxy
36 // socks{4,5}://<host>[:<port>] - SOCKS4/5 proxy
37 // kNoProxy - no proxy
38 typedef base::Callback<void(const std::deque<std::string>& proxies)>
39     ProxiesResolvedFn;
40 
41 // An id that identifies a proxy request. Used to cancel an ongoing request
42 // before the callback is called.
43 typedef brillo::MessageLoop::TaskId ProxyRequestId;
44 
45 // A constant identifying an invalid ProxyRequestId.
46 extern const ProxyRequestId kProxyRequestIdNull;
47 
48 class ProxyResolver {
49  public:
ProxyResolver()50   ProxyResolver() {}
~ProxyResolver()51   virtual ~ProxyResolver() {}
52 
53   // Finds proxies for the given URL and returns them via the callback.
54   // Returns the id of the pending request on success or kProxyRequestIdNull
55   // otherwise.
56   virtual ProxyRequestId GetProxiesForUrl(
57       const std::string& url, const ProxiesResolvedFn& callback) = 0;
58 
59   // Cancel the proxy resolution request initiated by GetProxiesForUrl(). The
60   // |request| value must be the one provided by GetProxiesForUrl().
61   virtual bool CancelProxyRequest(ProxyRequestId request) = 0;
62 
63  private:
64   DISALLOW_COPY_AND_ASSIGN(ProxyResolver);
65 };
66 
67 // Always says to not use a proxy
68 class DirectProxyResolver : public ProxyResolver {
69  public:
70   DirectProxyResolver() = default;
71   ~DirectProxyResolver() override;
72   ProxyRequestId GetProxiesForUrl(const std::string& url,
73                                   const ProxiesResolvedFn& callback) override;
74   bool CancelProxyRequest(ProxyRequestId request) override;
75 
76   // Set the number of direct (non-) proxies to be returned by resolver.
77   // The default value is 1; higher numbers are currently used in testing.
set_num_proxies(size_t num_proxies)78   inline void set_num_proxies(size_t num_proxies) {
79     num_proxies_ = num_proxies;
80   }
81 
82  private:
83   // The ID of the main loop callback.
84   brillo::MessageLoop::TaskId idle_callback_id_{
85       brillo::MessageLoop::kTaskIdNull};
86 
87   // Number of direct proxies to return on resolved list; currently used for
88   // testing.
89   size_t num_proxies_{1};
90 
91   // The MainLoop callback, from here we return to the client.
92   void ReturnCallback(const ProxiesResolvedFn& callback);
93   DISALLOW_COPY_AND_ASSIGN(DirectProxyResolver);
94 };
95 
96 }  // namespace chromeos_update_engine
97 
98 #endif  // UPDATE_ENGINE_PROXY_RESOLVER_H_
99