chrome/browser/ui/webui/ntp/suggestions_source.h

   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_SOURCE_H_
   6 #define CHROME_BROWSER_UI_WEBUI_NTP_SUGGESTIONS_SOURCE_H_
   7
   8 #include "base/basictypes.h"
   9
  10 class Profile;
  11 class SuggestionsCombiner;
  12
  13 namespace base {
  14 class DictionaryValue;
  15 }
  16
  17 // Interface for a source of suggested pages. The various sources will be
  18 // combined by the SuggestionsCombiner.
  19 class SuggestionsSource {
  20
  21  public:
  22   virtual ~SuggestionsSource() {}
  23
  24  protected:
  25   SuggestionsSource() {}
  26
  27   friend class SuggestionsCombiner;
  28
  29   // Enables or disables debug mode for the current source. The source is
  30   // expected to provide additional data when debug mode is enabled.
  31   virtual void SetDebug(bool enable) = 0;
  32
  33   // The source's weight indicates how many items from this source will be
  34   // selected by the combiner. If a source weight is x and the total weight of
  35   // all the sources is y, then the combiner will select x/y items from it.
  36   virtual int GetWeight() = 0;
  37
  38   // Returns the number of items this source can produce.
  39   virtual int GetItemCount() = 0;
  40
  41   // Removes the most important item from this source and returns it. The
  42   // returned item must be in the right format to be sent to the javascript,
  43   // which you typically get by calling NewTabUI::SetUrlTitleAndDirection. If
  44   // the source is empty this method returns null.
  45   // The caller takes ownership of the returned item.
  46   virtual base::DictionaryValue* PopItem() = 0;
  47
  48   // Requests that the source fetch its items. If the source is already fetching
  49   // it does not have to reset and can continue fetching.
  50   virtual void FetchItems(Profile* profile) = 0;
  51
  52   // Sets the combiner holding this suggestion source. This method can only
  53   // be called once.
  54   virtual void SetCombiner(SuggestionsCombiner* combiner) = 0;
  55
  56  private:
  57   DISALLOW_COPY_AND_ASSIGN(SuggestionsSource);
  58 };
  59
  60 #endif  // CHROME_BROWSER_UI_WEBUI_NTP_SUGGESTIONS_SOURCE_H_