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.
5 #ifndef CHROME_BROWSER_HISTORY_SCORED_HISTORY_MATCH_H_
6 #define CHROME_BROWSER_HISTORY_SCORED_HISTORY_MATCH_H_
12 #include "base/strings/string16.h"
13 #include "chrome/browser/history/in_memory_url_index_types.h"
14 #include "components/history/core/browser/history_match.h"
15 #include "components/history/core/browser/history_types.h"
16 #include "testing/gtest/include/gtest/gtest_prod.h"
21 class ScoredHistoryMatchTest;
23 // An HistoryMatch that has a score as well as metrics defining where in the
24 // history item's URL and/or page title matches have occurred.
25 class ScoredHistoryMatch : public history::HistoryMatch {
27 // The maximum number of recent visits to examine in GetFrequency().
28 // Public so url_index_private_data.cc knows how many visits it is
29 // expected to deliver (at minimum) to this class.
30 static const size_t kMaxVisitsToScore;
32 ScoredHistoryMatch(); // Required by STL.
34 // Creates a new match with a raw score calculated for the history item
35 // given in |row| with recent visits as indicated in |visits|. First
36 // determines if the row qualifies by seeing if all of the terms in
37 // |terms_vector| occur in |row|. If so, calculates a raw score. This raw
38 // score is in part determined by whether the matches occur at word
39 // boundaries, the locations of which are stored in |word_starts|. For some
40 // terms, it's appropriate to look for the word boundary within the term.
41 // For instance, the term ".net" should look for a word boundary at the "n".
42 // These offsets (".net" should have an offset of 1) come from
43 // |terms_to_word_starts_offsets|. |history_client| is used to determine
44 // if the match's URL is referenced by any bookmarks, which can also affect
45 // the raw score. The raw score allows the matches to be ordered and can be
46 // used to influence the final score calculated by the client of this index.
47 // If the row does not qualify the raw score will be 0. |languages| is used
48 // to help parse/format the URL before looking for the terms.
49 ScoredHistoryMatch(const URLRow& row,
50 const VisitInfoVector& visits,
51 const std::string& languages,
52 const base::string16& lower_string,
53 const String16Vector& terms_vector,
54 const WordStarts& terms_to_word_starts_offsets,
55 const RowWordStarts& word_starts,
57 HistoryClient* history_client);
58 ~ScoredHistoryMatch();
60 // Compares two matches by score. Functor supporting URLIndexPrivateData's
61 // HistoryItemsForTerms function. Looks at particular fields within
62 // with url_info to make tie-breaking a bit smarter.
63 static bool MatchScoreGreater(const ScoredHistoryMatch& m1,
64 const ScoredHistoryMatch& m2);
67 int raw_score() const { return raw_score_; }
68 const TermMatches& url_matches() const { return url_matches_; }
69 const TermMatches& title_matches() const { return title_matches_; }
70 bool can_inline() const { return can_inline_; }
72 // Returns |term_matches| after removing all matches that are not at a
73 // word break that are in the range [|start_pos|, |end_pos|).
74 // start_pos == string::npos is treated as start_pos = length of string.
75 // (In other words, no matches will be filtered.)
76 // end_pos == string::npos is treated as end_pos = length of string.
77 static TermMatches FilterTermMatchesByWordStarts(
78 const TermMatches& term_matches,
79 const WordStarts& terms_to_word_starts_offsets,
80 const WordStarts& word_starts,
85 friend class ScoredHistoryMatchTest;
86 FRIEND_TEST_ALL_PREFIXES(ScoredHistoryMatchTest, ScoringBookmarks);
87 FRIEND_TEST_ALL_PREFIXES(ScoredHistoryMatchTest, ScoringDiscountFrecency);
88 FRIEND_TEST_ALL_PREFIXES(ScoredHistoryMatchTest, ScoringScheme);
89 FRIEND_TEST_ALL_PREFIXES(ScoredHistoryMatchTest, ScoringTLD);
91 // The number of days of recency scores to precompute.
92 static const int kDaysToPrecomputeRecencyScoresFor;
94 // The number of raw term score buckets use; raw term scores
95 // greater this are capped at the score of the largest bucket.
96 static const int kMaxRawTermScore;
98 // Return a topicality score based on how many matches appear in the
99 // url and the page's title and where they are (e.g., at word
100 // boundaries). Revises |url_matches_| and |title_matches_| in the
101 // process so they only reflect matches used for scoring. (For
102 // instance, some mid-word matches are not given credit in scoring.)
103 float GetTopicalityScore(const int num_terms,
104 const base::string16& cleaned_up_url,
105 const WordStarts& terms_to_word_starts_offsets,
106 const RowWordStarts& word_starts);
108 // Precalculates raw_term_score_to_topicality_score_, used in
109 // GetTopicalityScore().
110 static void FillInTermScoreToTopicalityScoreArray();
112 // Returns a recency score based on |last_visit_days_ago|, which is
113 // how many days ago the page was last visited.
114 static float GetRecencyScore(int last_visit_days_ago);
116 // Pre-calculates days_ago_to_recency_numerator_, used in
117 // GetRecencyScore().
118 static void FillInDaysAgoToRecencyScoreArray();
120 // Examines the first kMaxVisitsToScore and return a score (higher is
121 // better) based the rate of visits, whether the page is bookmarked, and
122 // how often those visits are typed navigations (i.e., explicitly
123 // invoked by the user). |now| is passed in to avoid unnecessarily
124 // recomputing it frequently.
125 static float GetFrequency(const base::Time& now,
126 const bool bookmarked,
127 const VisitInfoVector& visits);
129 // Combines the two component scores into a final score that's
130 // an appropriate value to use as a relevancy score.
131 static float GetFinalRelevancyScore(
132 float topicality_score,
133 float frequency_score);
135 // Sets |also_do_hup_like_scoring_|,
136 // |max_assigned_score_for_non_inlineable_matches_|, |bookmark_value_|,
137 // |allow_tld_matches_|, and |allow_scheme_matches_| based on the field
141 // An interim score taking into consideration location and completeness
145 // Both these TermMatches contain the set of matches that are considered
146 // important. At this time, that means they exclude mid-word matches
147 // except in the hostname of the URL. (Technically, during early
148 // construction of ScoredHistoryMatch, they may contain all matches, but
149 // unimportant matches are eliminated by GetTopicalityScore(), called
150 // during construction.)
151 // Term matches within the URL.
152 TermMatches url_matches_;
153 // Term matches within the page title.
154 TermMatches title_matches_;
156 // True if this is a candidate for in-line autocompletion.
159 // Pre-computed information to speed up calculating recency scores.
160 // |days_ago_to_recency_score_| is a simple array mapping how long
161 // ago a page was visited (in days) to the recency score we should
162 // assign it. This allows easy lookups of scores without requiring
163 // math. This is initialized upon first use of GetRecencyScore(),
164 // which calls FillInDaysAgoToRecencyScoreArray(),
165 static float* days_ago_to_recency_score_;
167 // Pre-computed information to speed up calculating topicality
168 // scores. |raw_term_score_to_topicality_score_| is a simple array
169 // mapping how raw terms scores (a weighted sum of the number of
170 // hits for the term, weighted by how important the hit is:
171 // hostname, path, etc.) to the topicality score we should assign
172 // it. This allows easy lookups of scores without requiring math.
173 // This is initialized upon first use of GetTopicalityScore(),
174 // which calls FillInTermScoreToTopicalityScoreArray().
175 static float* raw_term_score_to_topicality_score_;
177 // Used so we initialize static variables only once (on first use).
178 static bool initialized_;
180 // Untyped visits to bookmarked pages score this, compared to 1 for
181 // untyped visits to non-bookmarked pages and 20 for typed visits.
182 static int bookmark_value_;
184 // If true, we allow input terms to match in the TLD (e.g., .com).
185 static bool allow_tld_matches_;
187 // If true, we allow input terms to match in the scheme (e.g., http://).
188 static bool allow_scheme_matches_;
190 // If true, assign raw scores to be max(whatever it normally would be,
191 // a score that's similar to the score HistoryURL provider would assign).
192 // This variable is set in the constructor by examining the field trial
194 static bool also_do_hup_like_scoring_;
196 // The maximum score that can be assigned to non-inlineable matches.
197 // This is useful because often we want inlineable matches to come
198 // first (even if they don't sometimes score as well as non-inlineable
199 // matches) because if a non-inlineable match comes first than all matches
200 // will get demoted later in HistoryQuickProvider to non-inlineable scores.
201 // Set to -1 to indicate no maximum score.
202 static int max_assigned_score_for_non_inlineable_matches_;
204 typedef std::vector<ScoredHistoryMatch> ScoredHistoryMatches;
206 } // namespace history
208 #endif // CHROME_BROWSER_HISTORY_SCORED_HISTORY_MATCH_H_