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 void (*ProxiesResolvedFn)(const std::deque<std::string>& proxies,
39                                   void* data);
40 
41 class ProxyResolver {
42  public:
ProxyResolver()43   ProxyResolver() {}
~ProxyResolver()44   virtual ~ProxyResolver() {}
45 
46   // Finds proxies for the given URL and returns them via the callback.
47   // |data| will be passed to the callback.
48   // Returns true on success.
49   virtual bool GetProxiesForUrl(const std::string& url,
50                                 ProxiesResolvedFn callback,
51                                 void* data) = 0;
52 
53  private:
54   DISALLOW_COPY_AND_ASSIGN(ProxyResolver);
55 };
56 
57 // Always says to not use a proxy
58 class DirectProxyResolver : public ProxyResolver {
59  public:
60   DirectProxyResolver() = default;
61   ~DirectProxyResolver() override;
62   bool GetProxiesForUrl(const std::string& url,
63                         ProxiesResolvedFn callback,
64                         void* data) override;
65 
66   // Set the number of direct (non-) proxies to be returned by resolver.
67   // The default value is 1; higher numbers are currently used in testing.
set_num_proxies(size_t num_proxies)68   inline void set_num_proxies(size_t num_proxies) {
69     num_proxies_ = num_proxies;
70   }
71 
72  private:
73   // The ID of the main loop callback.
74   brillo::MessageLoop::TaskId idle_callback_id_{
75       brillo::MessageLoop::kTaskIdNull};
76 
77   // Number of direct proxies to return on resolved list; currently used for
78   // testing.
79   size_t num_proxies_{1};
80 
81   // The MainLoop callback, from here we return to the client.
82   void ReturnCallback(ProxiesResolvedFn callback, void* data);
83   DISALLOW_COPY_AND_ASSIGN(DirectProxyResolver);
84 };
85 
86 }  // namespace chromeos_update_engine
87 
88 #endif  // UPDATE_ENGINE_PROXY_RESOLVER_H_
89