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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 // This file contains the zero-suggest autocomplete provider. This experimental
      6 // provider is invoked when the user focuses in the omnibox prior to editing,
      7 // and generates search query suggestions based on the current URL. To enable
      8 // this provider, point --experimental-zero-suggest-url-prefix at an
      9 // appropriate suggestion service.
     10 //
     11 // HUGE DISCLAIMER: This is just here for experimenting and will probably be
     12 // deleted entirely as we revise how suggestions work with the omnibox.
     13 
     14 #ifndef CHROME_BROWSER_AUTOCOMPLETE_ZERO_SUGGEST_PROVIDER_H_
     15 #define CHROME_BROWSER_AUTOCOMPLETE_ZERO_SUGGEST_PROVIDER_H_
     16 
     17 #include "base/basictypes.h"
     18 #include "base/compiler_specific.h"
     19 #include "base/memory/scoped_ptr.h"
     20 #include "chrome/browser/autocomplete/base_search_provider.h"
     21 #include "chrome/browser/autocomplete/search_provider.h"
     22 #include "components/metrics/proto/omnibox_event.pb.h"
     23 
     24 class TemplateURLService;
     25 
     26 namespace base {
     27 class ListValue;
     28 class Value;
     29 }
     30 
     31 namespace net {
     32 class URLFetcher;
     33 }
     34 
     35 namespace user_prefs {
     36 class PrefRegistrySyncable;
     37 }
     38 
     39 // Autocomplete provider for searches based on the current URL.
     40 //
     41 // The controller will call StartZeroSuggest when the user focuses in the
     42 // omnibox. After construction, the autocomplete controller repeatedly calls
     43 // Start() with some user input, each time expecting to receive an updated
     44 // set of matches.
     45 //
     46 // TODO(jered): Consider deleting this class and building this functionality
     47 // into SearchProvider after dogfood and after we break the association between
     48 // omnibox text and suggestions.
     49 class ZeroSuggestProvider : public BaseSearchProvider {
     50  public:
     51   // Creates and returns an instance of this provider.
     52   static ZeroSuggestProvider* Create(AutocompleteProviderListener* listener,
     53                                      Profile* profile);
     54 
     55   // Registers a preference used to cache zero suggest results.
     56   static void RegisterProfilePrefs(user_prefs::PrefRegistrySyncable* registry);
     57 
     58   // AutocompleteProvider:
     59   virtual void Start(const AutocompleteInput& input,
     60                      bool minimal_changes) OVERRIDE;
     61   virtual void DeleteMatch(const AutocompleteMatch& match) OVERRIDE;
     62 
     63   // Sets |field_trial_triggered_| to false.
     64   virtual void ResetSession() OVERRIDE;
     65 
     66  protected:
     67   // BaseSearchProvider:
     68   virtual void ModifyProviderInfo(
     69       metrics::OmniboxEventProto_ProviderInfo* provider_info) const OVERRIDE;
     70 
     71  private:
     72   ZeroSuggestProvider(AutocompleteProviderListener* listener,
     73                       Profile* profile);
     74 
     75   virtual ~ZeroSuggestProvider();
     76 
     77   // BaseSearchProvider:
     78   virtual bool StoreSuggestionResponse(const std::string& json_data,
     79                                        const base::Value& parsed_data) OVERRIDE;
     80   virtual const TemplateURL* GetTemplateURL(bool is_keyword) const OVERRIDE;
     81   virtual const AutocompleteInput GetInput(bool is_keyword) const OVERRIDE;
     82   virtual Results* GetResultsToFill(bool is_keyword) OVERRIDE;
     83   virtual bool ShouldAppendExtraParams(
     84       const SuggestResult& result) const OVERRIDE;
     85   virtual void StopSuggest() OVERRIDE;
     86   virtual void ClearAllResults() OVERRIDE;
     87   virtual int GetDefaultResultRelevance() const OVERRIDE;
     88   virtual void RecordDeletionResult(bool success) OVERRIDE;
     89   virtual void LogFetchComplete(bool success, bool is_keyword) OVERRIDE;
     90   virtual bool IsKeywordFetcher(const net::URLFetcher* fetcher) const OVERRIDE;
     91   virtual void UpdateMatches() OVERRIDE;
     92 
     93   // Adds AutocompleteMatches for each of the suggestions in |results| to
     94   // |map|.
     95   void AddSuggestResultsToMap(const SuggestResults& results, MatchMap* map);
     96 
     97   // Returns an AutocompleteMatch for a navigational suggestion |navigation|.
     98   AutocompleteMatch NavigationToMatch(const NavigationResult& navigation);
     99 
    100   // Fetches zero-suggest suggestions by sending a request using |suggest_url|.
    101   void Run(const GURL& suggest_url);
    102 
    103   // Converts the parsed results to a set of AutocompleteMatches and adds them
    104   // to |matches_|.  Also update the histograms for how many results were
    105   // received.
    106   void ConvertResultsToAutocompleteMatches();
    107 
    108   // Returns an AutocompleteMatch for the current URL. The match should be in
    109   // the top position so that pressing enter has the effect of reloading the
    110   // page.
    111   AutocompleteMatch MatchForCurrentURL();
    112 
    113   // When the user is in the Most Visited field trial, we ask the TopSites
    114   // service for the most visited URLs during Run().  It calls back to this
    115   // function to return those |urls|.
    116   void OnMostVisitedUrlsAvailable(const history::MostVisitedURLList& urls);
    117 
    118   // Returns the relevance score for the verbatim result.
    119   int GetVerbatimRelevance() const;
    120 
    121   // Whether we can show zero suggest on |current_page_url| without
    122   // sending |current_page_url| as a parameter to the server at |suggest_url|.
    123   bool CanShowZeroSuggestWithoutSendingURL(const GURL& suggest_url,
    124                                            const GURL& current_page_url) const;
    125 
    126   // Checks whether we have a set of zero suggest results cached, and if so
    127   // populates |matches_| with cached results.
    128   void MaybeUseCachedSuggestions();
    129 
    130   // Used to build default search engine URLs for suggested queries.
    131   TemplateURLService* template_url_service_;
    132 
    133   // The URL for which a suggestion fetch is pending.
    134   std::string current_query_;
    135 
    136   // The type of page the user is viewing (a search results page doing search
    137   // term replacement, an arbitrary URL, etc.).
    138   metrics::OmniboxEventProto::PageClassification current_page_classification_;
    139 
    140   // Copy of OmniboxEditModel::permanent_text_.
    141   base::string16 permanent_text_;
    142 
    143   // Fetcher used to retrieve results.
    144   scoped_ptr<net::URLFetcher> fetcher_;
    145 
    146   // Suggestion for the current URL.
    147   AutocompleteMatch current_url_match_;
    148 
    149   // Contains suggest and navigation results as well as relevance parsed from
    150   // the response for the most recent zero suggest input URL.
    151   Results results_;
    152 
    153   // Whether we are currently showing cached zero suggest results.
    154   bool results_from_cache_;
    155 
    156   history::MostVisitedURLList most_visited_urls_;
    157 
    158   // For callbacks that may be run after destruction.
    159   base::WeakPtrFactory<ZeroSuggestProvider> weak_ptr_factory_;
    160 
    161   DISALLOW_COPY_AND_ASSIGN(ZeroSuggestProvider);
    162 };
    163 
    164 #endif  // CHROME_BROWSER_AUTOCOMPLETE_ZERO_SUGGEST_PROVIDER_H_
    165