Omnibox: Truncate HistoryContents Searches at 10k Characters

chrome/browser/autocomplete/history_contents_provider.cc

 // Copyright (c) 2012 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_contents_provider.h"
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/metrics/histogram.h"
 #include "base/string_util.h"
 #include "base/utf_string_conversions.h"
 #include "chrome/browser/autocomplete/autocomplete_match.h"
 #include "chrome/browser/autocomplete/autocomplete_provider_listener.h"
 #include "chrome/browser/bookmarks/bookmark_model.h"
 #include "chrome/browser/bookmarks/bookmark_model_factory.h"
 #include "chrome/browser/history/history_service_factory.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/search_engines/template_url.h"
 #include "chrome/browser/search_engines/template_url_service.h"
 #include "chrome/browser/search_engines/template_url_service_factory.h"
 #include "chrome/common/url_constants.h"
 #include "googleurl/src/url_util.h"
 #include "net/base/net_util.h"
 
 using base::TimeTicks;
 using history::HistoryDatabase;
 
-namespace {
-
-// Number of days to search for full text results. The longer this is, the more
-// time it will take.
-const int kDaysToSearch = 30;
-
-}  // namespace
-
 HistoryContentsProvider::MatchReference::MatchReference(
     const history::URLResult* result,
     int relevance)
     : result(result),
       relevance(relevance) {
 }
 
 // static
 bool HistoryContentsProvider::MatchReference::CompareRelevance(
     const HistoryContentsProvider::MatchReference& lhs,
@@ skipping 82 matching lines @@
     results_.Swap(&empty_results);
   }
 
   if (input.matches_requested() == AutocompleteInput::ALL_MATCHES) {
     HistoryService* history =
         HistoryServiceFactory::GetForProfile(profile_,
                                              Profile::EXPLICIT_ACCESS);
     if (history) {
       done_ = false;
 
+      // Number of days to search for full text results. The longer
+      // this is, the more time it will take.
+      const int kDaysToSearch = 30;
+
+      // The maximum number of characters used in a search for full
+      // text results.  This was chosen arbitrarily because omnibox
+      // results that come back too late (after tens of seconds)
+      // aren't useful to the user so it's not worth spending CPU time
+      // on them.  Furthermore, if a URL matches the first 2k of
+      // characters the user typed (more likely pasted) into the
+      // omnibox, it's likely it matches the rest; there's strongly
+      // diminished returns for the ability to add additional search
+      // terms.
+      const size_t kMaxCharactersToConsider = 2000u;
+
       history::QueryOptions options;
       options.body_only = body_only_;
       options.SetRecentDayRange(kDaysToSearch);
       options.max_count = kMaxMatches;
-      history->QueryHistory(input.text(), options,
+      history->QueryHistory(
+          input.text().substr(0, kMaxCharactersToConsider),
+          options,
           &request_consumer_,
           base::Bind(&HistoryContentsProvider::QueryComplete,
                      base::Unretained(this)));
     }
   }
 }
 
 void HistoryContentsProvider::Stop(bool clear_cached_results) {
   done_ = true;
   request_consumer_.CancelAllRequests();
@@ skipping 112 matching lines @@
 
 int HistoryContentsProvider::CalculateRelevance(
     const history::URLResult& result) {
   const bool in_title = MatchInTitle(result);
   BookmarkModel* bm_model = BookmarkModelFactory::GetForProfile(profile_);
   if (!bm_model || !bm_model->IsBookmarked(result.url()))
     return in_title ? (700 + title_count_++) : (500 + contents_count_++);
   return in_title ?
       (1000 + star_title_count_++) : (550 + star_contents_count_++);
 }