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      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 
     16 struct TranslateEventDetails;
     17 class GURL;
     18 class TranslateURLFetcher;
     19 
     20 // The TranslateLanguageList class is responsible for maintaining the latest
     21 // supporting language list.
     22 class 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