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      1 // Copyright (c) 2012 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 CHROME_BROWSER_UI_WEBUI_NTP_SUGGESTIONS_COMBINER_H_
      6 #define CHROME_BROWSER_UI_WEBUI_NTP_SUGGESTIONS_COMBINER_H_
      7 
      8 #include <vector>
      9 
     10 #include "base/basictypes.h"
     11 #include "base/memory/scoped_ptr.h"
     12 #include "base/memory/scoped_vector.h"
     13 
     14 class GURL;
     15 class SuggestionsHandler;
     16 class SuggestionsSource;
     17 class Profile;
     18 
     19 namespace base {
     20 class DictionaryValue;
     21 class ListValue;
     22 }
     23 
     24 // Combines many different sources of suggestions and generates data from it.
     25 class SuggestionsCombiner {
     26  public:
     27   // Interface to be implemented by classes that will be notified of events from
     28   // the SuggestionsCombiner.
     29   class Delegate {
     30    public:
     31     virtual ~Delegate() {}
     32 
     33     // Method that is called when new suggestions are ready from the
     34     // SuggestionsCombiner.
     35     virtual void OnSuggestionsReady() = 0;
     36   };
     37 
     38   virtual ~SuggestionsCombiner();
     39 
     40   explicit SuggestionsCombiner(SuggestionsCombiner::Delegate* delegate,
     41                                Profile* profile);
     42 
     43   // Add a new source. The SuggestionsCombiner takes ownership of |source|.
     44   void AddSource(SuggestionsSource* source);
     45 
     46   // Enables or disables debug mode. If debug mode is enabled, the sources are
     47   // expected to provide additional data, which could be displayed, for example,
     48   // in the chrome://suggestions-internals/ page.
     49   void EnableDebug(bool enable);
     50 
     51   // Fetch a new set of items from the various suggestion sources.
     52   void FetchItems(Profile* profile);
     53 
     54   base::ListValue* GetPageValues();
     55 
     56   // Called by a source when its items are ready. Make sure suggestion sources
     57   // call this method exactly once for each call to
     58   // SuggestionsSource::FetchItems.
     59   void OnItemsReady();
     60 
     61   void SetSuggestionsCount(size_t suggestions_count);
     62 
     63   // Creates a new instance of the SuggestionsCombiner (owned by the callee),
     64   // and sets up the default sources.
     65   static SuggestionsCombiner* Create(SuggestionsCombiner::Delegate* delegate,
     66                                      Profile* profile);
     67 
     68  private:
     69   friend class SuggestionsCombinerTest;
     70 
     71   // Fill the page values from the suggestion sources so they can be sent to
     72   // the JavaScript side. This should only be called when all the suggestion
     73   // sources have items ready.
     74   void FillPageValues();
     75 
     76   // Add extra information to page values that should be common across all
     77   // suggestion sources.
     78   void AddExtendedInformation(base::DictionaryValue* page_value);
     79 
     80   // Checks if a URL is already open for the current profile. URLs open in an
     81   // incognito window are not reported.
     82   bool IsUrlAlreadyOpen(const GURL& url);
     83 
     84   typedef ScopedVector<SuggestionsSource> SuggestionsSources;
     85 
     86   // List of all the suggestions sources that will be combined to generate a
     87   // single list of suggestions.
     88   SuggestionsSources sources_;
     89 
     90   // Counter tracking the number of sources that are currently asynchronously
     91   // fetching their data.
     92   int sources_fetching_count_;
     93 
     94   // The delegate to notify once items are ready.
     95   SuggestionsCombiner::Delegate* delegate_;
     96 
     97   // Number of suggestions to generate. Used to distribute the suggestions
     98   // between the various sources.
     99   size_t suggestions_count_;
    100 
    101   // Informations to send to the javascript side.
    102   scoped_ptr<base::ListValue> page_values_;
    103 
    104   // Whether debug mode is enabled or not (debug mode provides more data in the
    105   // results).
    106   bool debug_enabled_;
    107 
    108   Profile* profile_;
    109 
    110   DISALLOW_COPY_AND_ASSIGN(SuggestionsCombiner);
    111 };
    112 
    113 #endif  // CHROME_BROWSER_UI_WEBUI_NTP_SUGGESTIONS_COMBINER_H_
    114