Add confidence to AutocompleteMatch.

chrome/browser/autocomplete/history_contents_provider.h

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROME_BROWSER_AUTOCOMPLETE_HISTORY_CONTENTS_PROVIDER_H_
 #define CHROME_BROWSER_AUTOCOMPLETE_HISTORY_CONTENTS_PROVIDER_H_
 #pragma once
 
 #include "chrome/browser/autocomplete/history_provider.h"
 #include "chrome/browser/history/history.h"
@@ skipping 17 matching lines @@
                           Profile* profile,
                           bool body_only);
 
   // As necessary asks the history service for the relevant results. When
   // done SetResults is invoked.
   virtual void Start(const AutocompleteInput& input,
                      bool minimal_changes) OVERRIDE;
   virtual void Stop() OVERRIDE;
 
  private:
+  // When processing the results from the history query, this structure points
+  // to a single result. It allows the results to be sorted and processed
+  // without modifying the larger and slower results structure.
+  struct MatchReference {
+    MatchReference(const history::URLResult* result,
+                   int relevance,
+                   float confidence);
+
+    static bool CompareRelevance(const MatchReference& lhs,
+                                 const MatchReference& rhs);
+
+    const history::URLResult* result;
+    int relevance;  // Score of relevance computed by CalculateRelevance.
+    float confidence;  // Confidence computed by CalculateConfidence.
+  };
+
   virtual ~HistoryContentsProvider();
 
   void QueryComplete(HistoryService::Handle handle,
                      history::QueryResults* results);
 
   // Converts each MatchingPageResult in results_ to an AutocompleteMatch and
   // adds it to matches_.
   void ConvertResults();
 
   // Creates and returns an AutocompleteMatch from a MatchingPageResult.
-  AutocompleteMatch ResultToMatch(const history::URLResult& result,
-                                  int score);
+  AutocompleteMatch ResultToMatch(const MatchReference& match_reference);
 
   // Adds ACMatchClassifications to match from the offset positions in
   // page_result.
   void ClassifyDescription(const history::URLResult& result,
                            AutocompleteMatch* match) const;
 
   // Calculates and returns the relevance of a particular result. See the
   // chart in autocomplete.h for the list of values this returns.
   int CalculateRelevance(const history::URLResult& result);
 
+  // Calculates and returns the confidence for a particular result. This is
+  // calculated by comparing the result's |visit_count| to that of all the
+  // results.
+  float CalculateConfidence(const history::URLResult& result,
+                            const history::QueryResults& results) const;

[mrossetti, 2011/08/09 23:40:43]

Same suggestion as for the HistoryQuickProvider: calculate the sum of the scores
in the ConvertResults function instead of recalculating it here for each match.
Or do you imagine that the confidence calculation might transmogrify into
something more complex?

[dominich, 2011/08/10 16:10:13]

There's a very good chance the details of the calculation will change. This
first version is deliberately naive to see if it alone can improve the success
rate of prerendering from the omnibox.

+
   // Queries the bookmarks for any bookmarks whose title matches input. All
   // matches are added directly to results_.
   void QueryBookmarks(const AutocompleteInput& input);
 
   // Converts a BookmarkModel::TitleMatch to a QueryResult and adds it to
   // results_.
   void AddBookmarkTitleMatchToResults(const bookmark_utils::TitleMatch& match);
 
   // Return true if the search term can be found in the title of |result|.
   bool MatchInTitle(const history::URLResult& result);
@@ skipping 26 matching lines @@
   // Whether results_ is valid (so we can tell invalid apart from empty).
   bool have_results_;
 
   // Current query string.
   string16 query_;
 
   DISALLOW_COPY_AND_ASSIGN(HistoryContentsProvider);
 };
 
 #endif  // CHROME_BROWSER_AUTOCOMPLETE_HISTORY_CONTENTS_PROVIDER_H_