translate_language_list.h revision a1401311d1ab56c4ed0a474bd38c108f75cb0cd9 
1// Copyright 2013 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 COMPONENTS_TRANSLATE_CORE_BROWSER_TRANSLATE_LANGUAGE_LIST_H_
6#define COMPONENTS_TRANSLATE_CORE_BROWSER_TRANSLATE_LANGUAGE_LIST_H_
7
8#include <set>
9#include <string>
10#include <vector>
11
12#include "base/callback_list.h"
13#include "base/memory/scoped_ptr.h"
14#include "base/time/time.h"
15
16struct TranslateEventDetails;
17class GURL;
18class TranslateURLFetcher;
19
20// The TranslateLanguageList class is responsible for maintaining the latest
21// supporting language list.
22class TranslateLanguageList {
23 public:
24  static const int kFetcherId = 1;
25
26  TranslateLanguageList();
27  virtual ~TranslateLanguageList();
28
29  // Returns the last-updated time when the language list is fetched from the
30  // Translate server. Returns null time if the list is yet to be fetched.
31  base::Time last_updated() { return last_updated_; }
32
33  // Fills |languages| with the list of languages that the translate server can
34  // translate to and from. |languages| will include alpha languages.
35  void GetSupportedLanguages(std::vector<std::string>* languages);
36
37  // Returns the language code that can be used with the Translate method for a
38  // specified |language|. (ex. GetLanguageCode("en-US") will return "en", and
39  // GetLanguageCode("zh-CN") returns "zh-CN")
40  std::string GetLanguageCode(const std::string& language);
41
42  // Returns true if |language| is supported by the translation server. It also
43  // returns true against alpha languages.
44  bool IsSupportedLanguage(const std::string& language);
45
46  // Returns true if |language| is supported by the translation server as a
47  // alpha language.
48  bool IsAlphaLanguage(const std::string& language);
49
50  // Fetches the language list from the translate server if resource requests
51  // are allowed, and otherwise keeps the request as pending until allowed.
52  void RequestLanguageList();
53
54  // Sets whether requests are allowed. If |allowed| is true, this resumes any
55  // pending request.
56  void SetResourceRequestsAllowed(bool allowed);
57
58  typedef base::Callback<void(const TranslateEventDetails&)> EventCallback;
59  typedef base::CallbackList<void(const TranslateEventDetails&)>
60      EventCallbackList;
61
62  // Registers a callback for translate events related to the language list,
63  // such as updates and download errors.
64  scoped_ptr<EventCallbackList::Subscription> RegisterEventCallback(
65      const EventCallback& callback);
66
67  // Disables the language list updater. This is used only for testing now.
68  static void DisableUpdate();
69
70  // static const values shared with our browser tests.
71  static const char kLanguageListCallbackName[];
72  static const char kTargetLanguagesKey[];
73  static const char kAlphaLanguagesKey[];
74
75 private:
76  // Callback function called when TranslateURLFetcher::Request() is finished.
77  void OnLanguageListFetchComplete(int id,
78                                   bool success,
79                                   const std::string& data);
80
81  // Notifies the callback list of a translate event.
82  void NotifyEvent(int line, const std::string& message);
83
84  // Parses |language_list| containing the list of languages that the translate
85  // server can translate to and from.
86  void SetSupportedLanguages(const std::string& language_list);
87
88  // Returns the url from which to load the list of languages.
89  GURL TranslateLanguageUrl();
90
91  // Callbacks called on translate events.
92  EventCallbackList callback_list_;
93
94  // Whether the language list can be requested.
95  bool resource_requests_allowed_;
96
97  // True if the list has to be fetched when resource requests are allowed.
98  bool request_pending_;
99
100  // All the languages supported by the translation server.
101  std::set<std::string> all_supported_languages_;
102
103  // Alpha languages supported by the translation server.
104  std::set<std::string> alpha_languages_;
105
106  // A LanguageListFetcher instance to fetch a server providing supported
107  // language list including alpha languages.
108  scoped_ptr<TranslateURLFetcher> language_list_fetcher_;
109
110  // The last-updated time when the language list is sent.
111  base::Time last_updated_;
112
113  DISALLOW_COPY_AND_ASSIGN(TranslateLanguageList);
114};
115
116#endif  // COMPONENTS_TRANSLATE_CORE_BROWSER_TRANSLATE_LANGUAGE_LIST_H_
117