Change scoring for history url provider.

chrome/browser/autocomplete/history_url_provider.cc

 // 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.
 
 #include "chrome/browser/autocomplete/history_url_provider.h"
 
 #include <algorithm>
 
 #include "base/basictypes.h"
 #include "base/message_loop.h"
@@ skipping 465 matching lines @@
 
     default:
       return 900 + static_cast<int>(match_number);
   }
 }
 
 // static
 float HistoryURLProvider::CalculateConfidence(
     const history::HistoryMatch& match,
     const history::HistoryMatches& matches) {
-  // TODO(dominich): Take into account bookmarked page?
-  // TODO(dominich): See CompareHistoryMatch for more measures to include.
-  // Using typed count in place of visit count as:
+  // Calculate a score based on typed count.
+  const float typed_numerator = match.url_info.typed_count();
+  float typed_denominator = 0.0f;
+  for (history::HistoryMatches::const_iterator it = matches.begin();
+       it != matches.end(); ++it) {
+    typed_denominator += it->url_info.typed_count();
+  }
+  const float typed_score = (typed_denominator > 0.0f) ?
+      (typed_numerator / typed_denominator) : 0.0f;
+
+  // Calculate a score based on visit count
+  const float visit_numerator = match.url_info.visit_count();
+  float visit_denominator = 0.0f;
+  for (history::HistoryMatches::const_iterator it = matches.begin();
+       it != matches.end(); ++it) {
+    visit_denominator += it->url_info.visit_count();
+  }
+  const float visit_score = (visit_denominator > 0.0f) ?
+      (visit_numerator / visit_denominator) : 0.0f;
+
+  // Calculate a score based on innermost matching.
+  const float innermost_score = (match.innermost_match ? 1.0f : 0.0f);
+
+  // TODO(dominich): Add a boost for bookmarked pages?
+  // Prefer typed count to visit count as:
   // - It's a better indicator of what the user wants to open given that they
   //   are typing in the address bar (users tend to open certain URLs by typing
   //   and others by e.g. bookmarks, so visit_count is a good indicator of
   //   overall interest but a bad one for specifically omnibox interest).
   // - Since the DB query is sorted by typed_count, the results may be
   //   effectively a random selection as far as visit_counts are concerned
   //   (meaning many high-visit_count-URLs may be present in one query and
   //   absent in a similar one), leading to wild swings in confidence for the
   //   same result across distinct queries.
-  float numerator = match.url_info.typed_count();
-  float denominator = 0.0f;
-  for (history::HistoryMatches::const_iterator it = matches.begin();
-       it != matches.end(); ++it) {
-    denominator += it->url_info.typed_count();
-  }
-  if (denominator < 1) {
-    numerator = match.url_info.visit_count();
-    for (history::HistoryMatches::const_iterator it = matches.begin();
-         it != matches.end(); ++it) {
-      denominator += it->url_info.visit_count();
-    }
-  }
-  return (denominator > 0.0f ? numerator / denominator : 0);
+  // Add a boost for innermost matches (matches after scheme or 'www.').
+  return (0.5f * typed_score) + (0.3f * visit_score) + (0.2f * innermost_score);
 }
 
 // static
 void HistoryURLProvider::PromoteOrCreateShorterSuggestion(
     history::URLDatabase* db,
     const HistoryURLProviderParams& params,
     bool have_what_you_typed_match,
     const AutocompleteMatch& what_you_typed_match,
     HistoryMatches* matches) {
   if (matches->empty())
@@ skipping 336 matching lines @@
         &match.contents_class);
   }
   match.description = info.title();
   AutocompleteMatch::ClassifyMatchInString(params->input.text(),
                                            info.title(),
                                            ACMatchClassification::NONE,
                                            &match.description_class);
 
   return match;
 }