Omnibox: Add Mid-Input Matching to HistoryQuick Provider

chrome/browser/history/url_index_private_data.h

 // 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.
 
 #ifndef CHROME_BROWSER_HISTORY_URL_INDEX_PRIVATE_DATA_H_
 #define CHROME_BROWSER_HISTORY_URL_INDEX_PRIVATE_DATA_H_
 
 #include <set>
 #include <string>
 
@@ skipping 32 matching lines @@
 // annotated.
 class URLIndexPrivateData
     : public base::RefCountedThreadSafe<URLIndexPrivateData> {
  public:
   URLIndexPrivateData();
 
   // Given a string16 in |term_string|, scans the history index and returns a
   // vector with all scored, matching history items. The |term_string| is
   // broken down into individual terms (words), each of which must occur in the
   // candidate history item's URL or page title for the item to qualify;
-  // however, the terms do not necessarily have to be adjacent. Once we have
-  // a set of candidates, they are filtered to insure that all |term_string|
-  // terms, as separated by whitespace, occur within the candidate's URL
-  // or page title. Scores are then calculated on no more than
-  // |kItemsToScoreLimit| candidates, as the scoring of such a large number of
-  // candidates may cause perceptible typing response delays in the omnibox.
-  // This is likely to occur for short omnibox terms such as 'h' and 'w' which
+  // however, the terms do not necessarily have to be adjacent. We
+  // also allow breaking |term_string| at |cursor_position| (if
+  // set). Once we have a set of candidates, they are filtered to ensure
+  // that all |term_string| terms, as separated by whitespace and the
+  // cursor (if set), occur within the candidate's URL or page title.
+  // Scores are then calculated on no more than |kItemsToScoreLimit|
+  // candidates, as the scoring of such a large number of candidates may
+  // cause perceptible typing response delays in the omnibox. This is
+  // likely to occur for short omnibox terms such as 'h' and 'w' which
   // will be found in nearly all history candidates. Results are sorted by
   // descending score. The full results set (i.e. beyond the
   // |kItemsToScoreLimit| limit) will be retained and used for subsequent calls
   // to this function. |bookmark_service| is used to boost a result's score if
   // its URL is referenced by one or more of the user's bookmarks.
-  ScoredHistoryMatches HistoryItemsForTerms(const string16& term_string,
+  ScoredHistoryMatches HistoryItemsForTerms(string16 term_string,
+                                            size_t cursor_position,
                                             BookmarkService* bookmark_service);
 
   // Adds the history item in |row| to the index if it does not already already
   // exist and it meets the minimum 'quick' criteria. If the row already exists
   // in the index then the index will be updated if the row still meets the
   // criteria, otherwise the row will be removed from the index. Returns true
   // if the index was actually updated. |languages| gives a list of language
   // encodings by which the URLs and page titles are broken down into words and
   // characters. |scheme_whitelist| is used to filter non-qualifying schemes.
   bool UpdateURL(const URLRow& row,
@@ skipping 40 matching lines @@
   void Clear();
 
  private:
   friend class base::RefCountedThreadSafe<URLIndexPrivateData>;
   ~URLIndexPrivateData();
 
   friend class AddHistoryMatch;
   friend class ::HistoryQuickProviderTest;
   friend class InMemoryURLIndexTest;
   FRIEND_TEST_ALL_PREFIXES(InMemoryURLIndexTest, CacheSaveRestore);
+  FRIEND_TEST_ALL_PREFIXES(InMemoryURLIndexTest, CursorPositionRetrieval);
   FRIEND_TEST_ALL_PREFIXES(InMemoryURLIndexTest, HugeResultSet);
   FRIEND_TEST_ALL_PREFIXES(InMemoryURLIndexTest, Scoring);
   FRIEND_TEST_ALL_PREFIXES(InMemoryURLIndexTest, TitleSearch);
   FRIEND_TEST_ALL_PREFIXES(InMemoryURLIndexTest, TypedCharacterCaching);
   FRIEND_TEST_ALL_PREFIXES(InMemoryURLIndexTest, WhitelistedURLs);
   FRIEND_TEST_ALL_PREFIXES(LimitedInMemoryURLIndexTest, Initialization);
 
   // Support caching of term results so that we can optimize searches which
   // build upon a previous search. Each entry in this map represents one
   // search term from the most recent search. For example, if the user had
@@ skipping 151 matching lines @@
   bool RestoreWordStartsMap(const imui::InMemoryURLIndexCacheItem& cache,
                             const std::string& languages);
 
   // Determines if |gurl| has a whitelisted scheme and returns true if so.
   static bool URLSchemeIsWhitelisted(const GURL& gurl,
                                      const std::set<std::string>& whitelist);
 
   // Cache of search terms.
   SearchTermCacheMap search_term_cache_;
 
+  // Whether to allow breaking the input at the cursor position.  Set based
+  // on whether the user is in the OmniboxHQPUseCursorPosition field trial
+  // experiment group.
+  bool use_cursor_position_;
+
   // Start of data members that are cached -------------------------------------
 
   // The version of the cache file most recently used to restore this instance
   // of the private data. If the private data was rebuilt from the history
   // database this will be 0.
   int restored_cache_version_;
 
   // A list of all of indexed words. The index of a word in this list is the
   // ID of the word in the word_map_. It reduces the memory overhead by
   // replacing a potentially long and repeated string with a simple index.
@@ skipping 44 matching lines @@
   // Used for unit testing only. Records the number of candidate history items
   // at three stages in the index searching process.
   size_t pre_filter_item_count_;    // After word index is queried.
   size_t post_filter_item_count_;   // After trimming large result set.
   size_t post_scoring_item_count_;  // After performing final filter/scoring.
 };
 
 }  // namespace history
 
 #endif  // CHROME_BROWSER_HISTORY_URL_INDEX_PRIVATE_DATA_H_