chrome/browser/autocomplete/shortcuts_provider.cc

   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.
   4
   5 #include "chrome/browser/autocomplete/shortcuts_provider.h"
   6
   7 #include <algorithm>
   8 #include <cmath>
   9 #include <map>
  10 #include <vector>
  11
  12 #include "base/i18n/break_iterator.h"
  13 #include "base/i18n/case_conversion.h"
  14 #include "base/logging.h"
  15 #include "base/metrics/histogram.h"
  16 #include "base/prefs/pref_service.h"
  17 #include "base/strings/string_number_conversions.h"
  18 #include "base/strings/string_util.h"
  19 #include "base/strings/utf_string_conversions.h"
  20 #include "base/time/time.h"
  21 #include "chrome/browser/autocomplete/autocomplete_input.h"
  22 #include "chrome/browser/autocomplete/autocomplete_provider_listener.h"
  23 #include "chrome/browser/autocomplete/autocomplete_result.h"
  24 #include "chrome/browser/autocomplete/history_provider.h"
  25 #include "chrome/browser/autocomplete/url_prefix.h"
  26 #include "chrome/browser/history/history_notifications.h"
  27 #include "chrome/browser/history/history_service.h"
  28 #include "chrome/browser/history/history_service_factory.h"
  29 #include "chrome/browser/history/shortcuts_backend_factory.h"
  30 #include "chrome/browser/omnibox/omnibox_field_trial.h"
  31 #include "chrome/browser/profiles/profile.h"
  32 #include "chrome/common/net/url_fixer_upper.h"
  33 #include "chrome/common/pref_names.h"
  34 #include "chrome/common/url_constants.h"
  35 #include "url/url_parse.h"
  36
  37 namespace {
  38
  39 class DestinationURLEqualsURL {
  40  public:
  41   explicit DestinationURLEqualsURL(const GURL& url) : url_(url) {}
  42   bool operator()(const AutocompleteMatch& match) const {
  43     return match.destination_url == url_;
  44   }
  45  private:
  46   const GURL url_;
  47 };
  48
  49 // Like URLPrefix::BestURLPrefix() except also handles the prefix of
  50 // "www.".  This is needed because sometimes the string we're matching
  51 // against here (which comes from |fill_into_edit|) can start with
  52 // "www." without having a protocol at the beginning.  Because "www."
  53 // is not on the default prefix list, we test for it explicitly here
  54 // and use that match if the default list didn't have a match or the
  55 // default list's match was shorter than it could've been.
  56 const URLPrefix* BestURLPrefixWithWWWCase(
  57     const base::string16& text,
  58     const base::string16& prefix_suffix) {
  59   CR_DEFINE_STATIC_LOCAL(URLPrefix, www_prefix,
  60                          (base::ASCIIToUTF16("www."), 1));
  61   const URLPrefix* best_prefix = URLPrefix::BestURLPrefix(text, prefix_suffix);
  62   if ((best_prefix == NULL) ||
  63       (best_prefix->num_components < www_prefix.num_components)) {
  64     if (URLPrefix::PrefixMatch(www_prefix, text, prefix_suffix))
  65       best_prefix = &www_prefix;
  66   }
  67   return best_prefix;
  68 }
  69
  70 }  // namespace
  71
  72 ShortcutsProvider::ShortcutsProvider(AutocompleteProviderListener* listener,
  73                                      Profile* profile)
  74     : AutocompleteProvider(listener, profile,
  75           AutocompleteProvider::TYPE_SHORTCUTS),
  76       languages_(profile_->GetPrefs()->GetString(prefs::kAcceptLanguages)),
  77       initialized_(false) {
  78   scoped_refptr<history::ShortcutsBackend> backend =
  79       ShortcutsBackendFactory::GetForProfile(profile_);
  80   if (backend.get()) {
  81     backend->AddObserver(this);
  82     if (backend->initialized())
  83       initialized_ = true;
  84   }
  85 }
  86
  87 void ShortcutsProvider::Start(const AutocompleteInput& input,
  88                               bool minimal_changes) {
  89   matches_.clear();
  90
  91   if ((input.type() == AutocompleteInput::INVALID) ||
  92       (input.type() == AutocompleteInput::FORCED_QUERY))
  93     return;
  94
  95   if (input.text().empty())
  96     return;
  97
  98   if (!initialized_)
  99     return;
 100
 101   base::TimeTicks start_time = base::TimeTicks::Now();
 102   GetMatches(input);
 103   if (input.text().length() < 6) {
 104     base::TimeTicks end_time = base::TimeTicks::Now();
 105     std::string name = "ShortcutsProvider.QueryIndexTime." +
 106         base::IntToString(input.text().size());
 107     base::HistogramBase* counter = base::Histogram::FactoryGet(
 108         name, 1, 1000, 50, base::Histogram::kUmaTargetedHistogramFlag);
 109     counter->Add(static_cast<int>((end_time - start_time).InMilliseconds()));
 110   }
 111   UpdateStarredStateOfMatches();
 112 }
 113
 114 void ShortcutsProvider::DeleteMatch(const AutocompleteMatch& match) {
 115   // Copy the URL since DeleteMatchesWithURLs() will invalidate |match|.
 116   GURL url(match.destination_url);
 117
 118   // When a user deletes a match, he probably means for the URL to disappear out
 119   // of history entirely. So nuke all shortcuts that map to this URL.
 120   scoped_refptr<history::ShortcutsBackend> backend =
 121       ShortcutsBackendFactory::GetForProfileIfExists(profile_);
 122   if (backend)  // Can be NULL in Incognito.
 123     backend->DeleteShortcutsWithUrl(url);
 124   matches_.erase(std::remove_if(matches_.begin(), matches_.end(),
 125                                 DestinationURLEqualsURL(url)),
 126                  matches_.end());
 127   // NOTE: |match| is now dead!
 128   listener_->OnProviderUpdate(true);
 129
 130   // Delete the match from the history DB. This will eventually result in a
 131   // second call to DeleteShortcutsWithURLs(), which is harmless.
 132   HistoryService* const history_service =
 133       HistoryServiceFactory::GetForProfile(profile_, Profile::EXPLICIT_ACCESS);
 134
 135   DCHECK(history_service && url.is_valid());
 136   history_service->DeleteURL(url);
 137 }
 138
 139 ShortcutsProvider::~ShortcutsProvider() {
 140   scoped_refptr<history::ShortcutsBackend> backend =
 141       ShortcutsBackendFactory::GetForProfileIfExists(profile_);
 142   if (backend.get())
 143     backend->RemoveObserver(this);
 144 }
 145
 146 void ShortcutsProvider::OnShortcutsLoaded() {
 147   initialized_ = true;
 148 }
 149
 150 void ShortcutsProvider::GetMatches(const AutocompleteInput& input) {
 151   scoped_refptr<history::ShortcutsBackend> backend =
 152       ShortcutsBackendFactory::GetForProfileIfExists(profile_);
 153   if (!backend.get())
 154     return;
 155   // Get the URLs from the shortcuts database with keys that partially or
 156   // completely match the search term.
 157   base::string16 term_string(base::i18n::ToLower(input.text()));
 158   DCHECK(!term_string.empty());
 159
 160   base::string16 fixed_up_term_string(term_string);
 161   AutocompleteInput fixed_up_input(input);
 162   if (FixupUserInput(&fixed_up_input))
 163     fixed_up_term_string = fixed_up_input.text();
 164
 165   int max_relevance;
 166   if (!OmniboxFieldTrial::ShortcutsScoringMaxRelevance(
 167       input.current_page_classification(), &max_relevance))
 168     max_relevance = AutocompleteResult::kLowestDefaultScore - 1;
 169
 170   for (history::ShortcutsBackend::ShortcutMap::const_iterator it =
 171            FindFirstMatch(term_string, backend.get());
 172        it != backend->shortcuts_map().end() &&
 173            StartsWith(it->first, term_string, true); ++it) {
 174     // Don't return shortcuts with zero relevance.
 175     int relevance = CalculateScore(term_string, it->second, max_relevance);
 176     if (relevance) {
 177       matches_.push_back(ShortcutToACMatch(
 178           it->second, relevance, term_string, fixed_up_term_string,
 179           input.prevent_inline_autocomplete()));
 180     }
 181   }
 182   std::partial_sort(matches_.begin(),
 183       matches_.begin() +
 184           std::min(AutocompleteProvider::kMaxMatches, matches_.size()),
 185       matches_.end(), &AutocompleteMatch::MoreRelevant);
 186   if (matches_.size() > AutocompleteProvider::kMaxMatches) {
 187     matches_.erase(matches_.begin() + AutocompleteProvider::kMaxMatches,
 188                    matches_.end());
 189   }
 190   // Reset relevance scores to guarantee no match is given a score that may
 191   // allow it to become the highest ranked match (i.e., the default match)
 192   // unless either it is a legal default match (i.e., inlineable) or the
 193   // omnibox will reorder matches as necessary to correct the problem.  In
 194   // the process of resetting scores, guarantee that all scores are decreasing
 195   // (but do not assign any scores below 1).
 196   if (!OmniboxFieldTrial::ReorderForLegalDefaultMatch(
 197           input.current_page_classification()) &&
 198       (matches_.empty() || !matches_.front().allowed_to_be_default_match)) {
 199     max_relevance = std::min(max_relevance,
 200                              AutocompleteResult::kLowestDefaultScore - 1);
 201   }
 202   for (ACMatches::iterator it = matches_.begin(); it != matches_.end(); ++it) {
 203     max_relevance = std::min(max_relevance, it->relevance);
 204     it->relevance = max_relevance;
 205     if (max_relevance > 1)
 206       --max_relevance;
 207   }
 208 }
 209
 210 AutocompleteMatch ShortcutsProvider::ShortcutToACMatch(
 211     const history::ShortcutsBackend::Shortcut& shortcut,
 212     int relevance,
 213     const base::string16& term_string,
 214     const base::string16& fixed_up_term_string,
 215     const bool prevent_inline_autocomplete) {
 216   DCHECK(!term_string.empty());
 217   AutocompleteMatch match(shortcut.match_core.ToMatch());
 218   match.provider = this;
 219   match.relevance = relevance;
 220   match.deletable = true;
 221   DCHECK(match.destination_url.is_valid());
 222   match.RecordAdditionalInfo("number of hits", shortcut.number_of_hits);
 223   match.RecordAdditionalInfo("last access time", shortcut.last_access_time);
 224   match.RecordAdditionalInfo("original input text",
 225                              base::UTF16ToUTF8(shortcut.text));
 226
 227   // Set |inline_autocompletion| and |allowed_to_be_default_match| if possible.
 228   // If the match is a search query this is easy: simply check whether the
 229   // user text is a prefix of the query.  If the match is a navigation, we
 230   // assume the fill_into_edit looks something like a URL, so we use
 231   // BestURLPrefix() to try and strip off any prefixes that the user might
 232   // not think would change the meaning, but would otherwise prevent inline
 233   // autocompletion.  This allows, for example, the input of "foo.c" to
 234   // autocomplete to "foo.com" for a fill_into_edit of "http://foo.com".
 235   if (AutocompleteMatch::IsSearchType(match.type)) {
 236     if (StartsWith(match.fill_into_edit, term_string, false)) {
 237       match.inline_autocompletion =
 238           match.fill_into_edit.substr(term_string.length());
 239       match.allowed_to_be_default_match =
 240           !prevent_inline_autocomplete || match.inline_autocompletion.empty();
 241     }
 242   } else {
 243     const URLPrefix* best_prefix =
 244         BestURLPrefixWithWWWCase(match.fill_into_edit, term_string);
 245     const base::string16* matching_string = &term_string;
 246     // If we failed to find a best_prefix initially, try again using a
 247     // fixed-up version of the user input.  This is especially useful to
 248     // get about: URLs to inline against chrome:// shortcuts.  (about:
 249     // URLs are fixed up to the chrome:// scheme.)
 250     if ((best_prefix == NULL) && !fixed_up_term_string.empty() &&
 251         (fixed_up_term_string != term_string)) {
 252         best_prefix = BestURLPrefixWithWWWCase(
 253             match.fill_into_edit, fixed_up_term_string);
 254         matching_string = &fixed_up_term_string;
 255     }
 256     if (best_prefix != NULL) {
 257       match.inline_autocompletion = match.fill_into_edit.substr(
 258           best_prefix->prefix.length() + matching_string->length());
 259       match.allowed_to_be_default_match =
 260           !prevent_inline_autocomplete || match.inline_autocompletion.empty();
 261     }
 262   }
 263
 264   // Try to mark pieces of the contents and description as matches if they
 265   // appear in |term_string|.
 266   WordMap terms_map(CreateWordMapForString(term_string));
 267   if (!terms_map.empty()) {
 268     match.contents_class = ClassifyAllMatchesInString(term_string, terms_map,
 269         match.contents, match.contents_class);
 270     match.description_class = ClassifyAllMatchesInString(term_string, terms_map,
 271         match.description, match.description_class);
 272   }
 273   return match;
 274 }
 275
 276 // static
 277 ShortcutsProvider::WordMap ShortcutsProvider::CreateWordMapForString(
 278     const base::string16& text) {
 279   // First, convert |text| to a vector of the unique words in it.
 280   WordMap word_map;
 281   base::i18n::BreakIterator word_iter(text,
 282                                       base::i18n::BreakIterator::BREAK_WORD);
 283   if (!word_iter.Init())
 284     return word_map;
 285   std::vector<base::string16> words;
 286   while (word_iter.Advance()) {
 287     if (word_iter.IsWord())
 288       words.push_back(word_iter.GetString());
 289   }
 290   if (words.empty())
 291     return word_map;
 292   std::sort(words.begin(), words.end());
 293   words.erase(std::unique(words.begin(), words.end()), words.end());
 294
 295   // Now create a map from (first character) to (words beginning with that
 296   // character).  We insert in reverse lexicographical order and rely on the
 297   // multimap preserving insertion order for values with the same key.  (This
 298   // is mandated in C++11, and part of that decision was based on a survey of
 299   // existing implementations that found that it was already true everywhere.)
 300   std::reverse(words.begin(), words.end());
 301   for (std::vector<base::string16>::const_iterator i(words.begin());
 302        i != words.end(); ++i)
 303     word_map.insert(std::make_pair((*i)[0], *i));
 304   return word_map;
 305 }
 306
 307 // static
 308 ACMatchClassifications ShortcutsProvider::ClassifyAllMatchesInString(
 309     const base::string16& find_text,
 310     const WordMap& find_words,
 311     const base::string16& text,
 312     const ACMatchClassifications& original_class) {
 313   DCHECK(!find_text.empty());
 314   DCHECK(!find_words.empty());
 315
 316   // The code below assumes |text| is nonempty and therefore the resulting
 317   // classification vector should always be nonempty as well.  Returning early
 318   // if |text| is empty assures we'll return the (correct) empty vector rather
 319   // than a vector with a single (0, NONE) match.
 320   if (text.empty())
 321     return original_class;
 322
 323   // First check whether |text| begins with |find_text| and mark that whole
 324   // section as a match if so.
 325   base::string16 text_lowercase(base::i18n::ToLower(text));
 326   ACMatchClassifications match_class;
 327   size_t last_position = 0;
 328   if (StartsWith(text_lowercase, find_text, true)) {
 329     match_class.push_back(
 330         ACMatchClassification(0, ACMatchClassification::MATCH));
 331     last_position = find_text.length();
 332     // If |text_lowercase| is actually equal to |find_text|, we don't need to
 333     // (and in fact shouldn't) put a trailing NONE classification after the end
 334     // of the string.
 335     if (last_position < text_lowercase.length()) {
 336       match_class.push_back(
 337           ACMatchClassification(last_position, ACMatchClassification::NONE));
 338     }
 339   } else {
 340     // |match_class| should start at position 0.  If the first matching word is
 341     // found at position 0, this will be popped from the vector further down.
 342     match_class.push_back(
 343         ACMatchClassification(0, ACMatchClassification::NONE));
 344   }
 345
 346   // Now, starting with |last_position|, check each character in
 347   // |text_lowercase| to see if we have words starting with that character in
 348   // |find_words|.  If so, check each of them to see if they match the portion
 349   // of |text_lowercase| beginning with |last_position|.  Accept the first
 350   // matching word found (which should be the longest possible match at this
 351   // location, given the construction of |find_words|) and add a MATCH region to
 352   // |match_class|, moving |last_position| to be after the matching word.  If we
 353   // found no matching words, move to the next character and repeat.
 354   while (last_position < text_lowercase.length()) {
 355     std::pair<WordMap::const_iterator, WordMap::const_iterator> range(
 356         find_words.equal_range(text_lowercase[last_position]));
 357     size_t next_character = last_position + 1;
 358     for (WordMap::const_iterator i(range.first); i != range.second; ++i) {
 359       const base::string16& word = i->second;
 360       size_t word_end = last_position + word.length();
 361       if ((word_end <= text_lowercase.length()) &&
 362           !text_lowercase.compare(last_position, word.length(), word)) {
 363         // Collapse adjacent ranges into one.
 364         if (match_class.back().offset == last_position)
 365           match_class.pop_back();
 366
 367         AutocompleteMatch::AddLastClassificationIfNecessary(&match_class,
 368             last_position, ACMatchClassification::MATCH);
 369         if (word_end < text_lowercase.length()) {
 370           match_class.push_back(
 371               ACMatchClassification(word_end, ACMatchClassification::NONE));
 372         }
 373         last_position = word_end;
 374         break;
 375       }
 376     }
 377     last_position = std::max(last_position, next_character);
 378   }
 379
 380   return AutocompleteMatch::MergeClassifications(original_class, match_class);
 381 }
 382
 383 history::ShortcutsBackend::ShortcutMap::const_iterator
 384     ShortcutsProvider::FindFirstMatch(const base::string16& keyword,
 385                                       history::ShortcutsBackend* backend) {
 386   DCHECK(backend);
 387   history::ShortcutsBackend::ShortcutMap::const_iterator it =
 388       backend->shortcuts_map().lower_bound(keyword);
 389   // Lower bound not necessarily matches the keyword, check for item pointed by
 390   // the lower bound iterator to at least start with keyword.
 391   return ((it == backend->shortcuts_map().end()) ||
 392     StartsWith(it->first, keyword, true)) ? it :
 393     backend->shortcuts_map().end();
 394 }
 395
 396 int ShortcutsProvider::CalculateScore(
 397     const base::string16& terms,
 398     const history::ShortcutsBackend::Shortcut& shortcut,
 399     int max_relevance) {
 400   DCHECK(!terms.empty());
 401   DCHECK_LE(terms.length(), shortcut.text.length());
 402
 403   // The initial score is based on how much of the shortcut the user has typed.
 404   // Using the square root of the typed fraction boosts the base score rapidly
 405   // as characters are typed, compared with simply using the typed fraction
 406   // directly. This makes sense since the first characters typed are much more
 407   // important for determining how likely it is a user wants a particular
 408   // shortcut than are the remaining continued characters.
 409   double base_score = max_relevance *
 410       sqrt(static_cast<double>(terms.length()) / shortcut.text.length());
 411
 412   // Then we decay this by half each week.
 413   const double kLn2 = 0.6931471805599453;
 414   base::TimeDelta time_passed = base::Time::Now() - shortcut.last_access_time;
 415   // Clamp to 0 in case time jumps backwards (e.g. due to DST).
 416   double decay_exponent = std::max(0.0, kLn2 * static_cast<double>(
 417       time_passed.InMicroseconds()) / base::Time::kMicrosecondsPerWeek);
 418
 419   // We modulate the decay factor based on how many times the shortcut has been
 420   // used. Newly created shortcuts decay at full speed; otherwise, decaying by
 421   // half takes |n| times as much time, where n increases by
 422   // (1.0 / each 5 additional hits), up to a maximum of 5x as long.
 423   const double kMaxDecaySpeedDivisor = 5.0;
 424   const double kNumUsesPerDecaySpeedDivisorIncrement = 5.0;
 425   double decay_divisor = std::min(kMaxDecaySpeedDivisor,
 426       (shortcut.number_of_hits + kNumUsesPerDecaySpeedDivisorIncrement - 1) /
 427       kNumUsesPerDecaySpeedDivisorIncrement);
 428
 429   return static_cast<int>((base_score / exp(decay_exponent / decay_divisor)) +
 430       0.5);
 431 }