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/history_provider.h"
  22 #include "chrome/browser/autocomplete/shortcuts_backend_factory.h"
  23 #include "chrome/browser/history/history_notifications.h"
  24 #include "chrome/browser/history/history_service.h"
  25 #include "chrome/browser/history/history_service_factory.h"
  26 #include "chrome/browser/profiles/profile.h"
  27 #include "chrome/browser/search_engines/template_url_service_factory.h"
  28 #include "chrome/common/pref_names.h"
  29 #include "chrome/common/url_constants.h"
  30 #include "components/metrics/proto/omnibox_input_type.pb.h"
  31 #include "components/omnibox/autocomplete_input.h"
  32 #include "components/omnibox/autocomplete_match.h"
  33 #include "components/omnibox/autocomplete_result.h"
  34 #include "components/omnibox/omnibox_field_trial.h"
  35 #include "components/omnibox/url_prefix.h"
  36 #include "components/url_fixer/url_fixer.h"
  37 #include "url/url_parse.h"
  38
  39 namespace {
  40
  41 class DestinationURLEqualsURL {
  42  public:
  43   explicit DestinationURLEqualsURL(const GURL& url) : url_(url) {}
  44   bool operator()(const AutocompleteMatch& match) const {
  45     return match.destination_url == url_;
  46   }
  47  private:
  48   const GURL url_;
  49 };
  50
  51 }  // namespace
  52
  53 const int ShortcutsProvider::kShortcutsProviderDefaultMaxRelevance = 1199;
  54
  55 ShortcutsProvider::ShortcutsProvider(Profile* profile)
  56     : AutocompleteProvider(AutocompleteProvider::TYPE_SHORTCUTS),
  57       profile_(profile),
  58       languages_(profile_->GetPrefs()->GetString(prefs::kAcceptLanguages)),
  59       initialized_(false) {
  60   scoped_refptr<ShortcutsBackend> backend =
  61       ShortcutsBackendFactory::GetForProfile(profile_);
  62   if (backend.get()) {
  63     backend->AddObserver(this);
  64     if (backend->initialized())
  65       initialized_ = true;
  66   }
  67 }
  68
  69 void ShortcutsProvider::Start(const AutocompleteInput& input,
  70                               bool minimal_changes) {
  71   matches_.clear();
  72
  73   if ((input.type() == metrics::OmniboxInputType::INVALID) ||
  74       (input.type() == metrics::OmniboxInputType::FORCED_QUERY))
  75     return;
  76
  77   if (input.text().empty())
  78     return;
  79
  80   if (!initialized_)
  81     return;
  82
  83   base::TimeTicks start_time = base::TimeTicks::Now();
  84   GetMatches(input);
  85   if (input.text().length() < 6) {
  86     base::TimeTicks end_time = base::TimeTicks::Now();
  87     std::string name = "ShortcutsProvider.QueryIndexTime." +
  88         base::IntToString(input.text().size());
  89     base::HistogramBase* counter = base::Histogram::FactoryGet(
  90         name, 1, 1000, 50, base::Histogram::kUmaTargetedHistogramFlag);
  91     counter->Add(static_cast<int>((end_time - start_time).InMilliseconds()));
  92   }
  93 }
  94
  95 void ShortcutsProvider::DeleteMatch(const AutocompleteMatch& match) {
  96   // Copy the URL since deleting from |matches_| will invalidate |match|.
  97   GURL url(match.destination_url);
  98   DCHECK(url.is_valid());
  99
 100   // When a user deletes a match, he probably means for the URL to disappear out
 101   // of history entirely. So nuke all shortcuts that map to this URL.
 102   scoped_refptr<ShortcutsBackend> backend =
 103       ShortcutsBackendFactory::GetForProfileIfExists(profile_);
 104   if (backend) // Can be NULL in Incognito.
 105     backend->DeleteShortcutsWithURL(url);
 106
 107   matches_.erase(std::remove_if(matches_.begin(), matches_.end(),
 108                                 DestinationURLEqualsURL(url)),
 109                  matches_.end());
 110   // NOTE: |match| is now dead!
 111
 112   // Delete the match from the history DB. This will eventually result in a
 113   // second call to DeleteShortcutsWithURL(), which is harmless.
 114   HistoryService* const history_service =
 115       HistoryServiceFactory::GetForProfile(profile_, Profile::EXPLICIT_ACCESS);
 116   DCHECK(history_service);
 117   history_service->DeleteURL(url);
 118 }
 119
 120 ShortcutsProvider::~ShortcutsProvider() {
 121   scoped_refptr<ShortcutsBackend> backend =
 122       ShortcutsBackendFactory::GetForProfileIfExists(profile_);
 123   if (backend.get())
 124     backend->RemoveObserver(this);
 125 }
 126
 127 void ShortcutsProvider::OnShortcutsLoaded() {
 128   initialized_ = true;
 129 }
 130
 131 void ShortcutsProvider::GetMatches(const AutocompleteInput& input) {
 132   scoped_refptr<ShortcutsBackend> backend =
 133       ShortcutsBackendFactory::GetForProfileIfExists(profile_);
 134   if (!backend.get())
 135     return;
 136   // Get the URLs from the shortcuts database with keys that partially or
 137   // completely match the search term.
 138   base::string16 term_string(base::i18n::ToLower(input.text()));
 139   DCHECK(!term_string.empty());
 140
 141   int max_relevance;
 142   if (!OmniboxFieldTrial::ShortcutsScoringMaxRelevance(
 143       input.current_page_classification(), &max_relevance))
 144     max_relevance = kShortcutsProviderDefaultMaxRelevance;
 145   TemplateURLService* template_url_service =
 146       TemplateURLServiceFactory::GetForProfile(profile_);
 147   const base::string16 fixed_up_input(FixupUserInput(input).second);
 148   for (ShortcutsBackend::ShortcutMap::const_iterator it =
 149            FindFirstMatch(term_string, backend.get());
 150        it != backend->shortcuts_map().end() &&
 151            StartsWith(it->first, term_string, true); ++it) {
 152     // Don't return shortcuts with zero relevance.
 153     int relevance = CalculateScore(term_string, it->second, max_relevance);
 154     if (relevance) {
 155       matches_.push_back(ShortcutToACMatch(it->second, relevance, input,
 156                                            fixed_up_input));
 157       matches_.back().ComputeStrippedDestinationURL(template_url_service);
 158     }
 159   }
 160   // Remove duplicates.  Duplicates don't need to be preserved in the matches
 161   // because they are only used for deletions, and shortcuts deletes matches
 162   // based on the URL.
 163   AutocompleteResult::DedupMatchesByDestination(
 164       input.current_page_classification(), false, &matches_);
 165   // Find best matches.
 166   std::partial_sort(matches_.begin(),
 167       matches_.begin() +
 168           std::min(AutocompleteProvider::kMaxMatches, matches_.size()),
 169       matches_.end(), &AutocompleteMatch::MoreRelevant);
 170   if (matches_.size() > AutocompleteProvider::kMaxMatches) {
 171     matches_.erase(matches_.begin() + AutocompleteProvider::kMaxMatches,
 172                    matches_.end());
 173   }
 174   // Guarantee that all scores are decreasing (but do not assign any scores
 175   // below 1).
 176   for (ACMatches::iterator it = matches_.begin(); it != matches_.end(); ++it) {
 177     max_relevance = std::min(max_relevance, it->relevance);
 178     it->relevance = max_relevance;
 179     if (max_relevance > 1)
 180       --max_relevance;
 181   }
 182 }
 183
 184 AutocompleteMatch ShortcutsProvider::ShortcutToACMatch(
 185     const history::ShortcutsDatabase::Shortcut& shortcut,
 186     int relevance,
 187     const AutocompleteInput& input,
 188     const base::string16& fixed_up_input_text) {
 189   DCHECK(!input.text().empty());
 190   AutocompleteMatch match;
 191   match.provider = this;
 192   match.relevance = relevance;
 193   match.deletable = true;
 194   match.fill_into_edit = shortcut.match_core.fill_into_edit;
 195   match.destination_url = shortcut.match_core.destination_url;
 196   DCHECK(match.destination_url.is_valid());
 197   match.contents = shortcut.match_core.contents;
 198   match.contents_class = AutocompleteMatch::ClassificationsFromString(
 199       shortcut.match_core.contents_class);
 200   match.description = shortcut.match_core.description;
 201   match.description_class = AutocompleteMatch::ClassificationsFromString(
 202       shortcut.match_core.description_class);
 203   match.transition =
 204       static_cast<content::PageTransition>(shortcut.match_core.transition);
 205   match.type = static_cast<AutocompleteMatch::Type>(shortcut.match_core.type);
 206   match.keyword = shortcut.match_core.keyword;
 207   match.RecordAdditionalInfo("number of hits", shortcut.number_of_hits);
 208   match.RecordAdditionalInfo("last access time", shortcut.last_access_time);
 209   match.RecordAdditionalInfo("original input text",
 210                              base::UTF16ToUTF8(shortcut.text));
 211
 212   // Set |inline_autocompletion| and |allowed_to_be_default_match| if possible.
 213   // If the match is a search query this is easy: simply check whether the
 214   // user text is a prefix of the query.  If the match is a navigation, we
 215   // assume the fill_into_edit looks something like a URL, so we use
 216   // URLPrefix::GetInlineAutocompleteOffset() to try and strip off any prefixes
 217   // that the user might not think would change the meaning, but would
 218   // otherwise prevent inline autocompletion.  This allows, for example, the
 219   // input of "foo.c" to autocomplete to "foo.com" for a fill_into_edit of
 220   // "http://foo.com".
 221   if (AutocompleteMatch::IsSearchType(match.type)) {
 222     if (StartsWith(match.fill_into_edit, input.text(), false)) {
 223       match.inline_autocompletion =
 224           match.fill_into_edit.substr(input.text().length());
 225       match.allowed_to_be_default_match =
 226           !input.prevent_inline_autocomplete() ||
 227           match.inline_autocompletion.empty();
 228     }
 229   } else {
 230     const size_t inline_autocomplete_offset =
 231         URLPrefix::GetInlineAutocompleteOffset(
 232             input.text(), fixed_up_input_text, true, match.fill_into_edit);
 233     if (inline_autocomplete_offset != base::string16::npos) {
 234       match.inline_autocompletion =
 235           match.fill_into_edit.substr(inline_autocomplete_offset);
 236       match.allowed_to_be_default_match =
 237           !HistoryProvider::PreventInlineAutocomplete(input) ||
 238           match.inline_autocompletion.empty();
 239     }
 240   }
 241   match.EnsureUWYTIsAllowedToBeDefault(
 242       input.canonicalized_url(),
 243       TemplateURLServiceFactory::GetForProfile(profile_));
 244
 245   // Try to mark pieces of the contents and description as matches if they
 246   // appear in |input.text()|.
 247   const base::string16 term_string = base::i18n::ToLower(input.text());
 248   WordMap terms_map(CreateWordMapForString(term_string));
 249   if (!terms_map.empty()) {
 250     match.contents_class = ClassifyAllMatchesInString(term_string, terms_map,
 251         match.contents, match.contents_class);
 252     match.description_class = ClassifyAllMatchesInString(term_string, terms_map,
 253         match.description, match.description_class);
 254   }
 255   return match;
 256 }
 257
 258 // static
 259 ShortcutsProvider::WordMap ShortcutsProvider::CreateWordMapForString(
 260     const base::string16& text) {
 261   // First, convert |text| to a vector of the unique words in it.
 262   WordMap word_map;
 263   base::i18n::BreakIterator word_iter(text,
 264                                       base::i18n::BreakIterator::BREAK_WORD);
 265   if (!word_iter.Init())
 266     return word_map;
 267   std::vector<base::string16> words;
 268   while (word_iter.Advance()) {
 269     if (word_iter.IsWord())
 270       words.push_back(word_iter.GetString());
 271   }
 272   if (words.empty())
 273     return word_map;
 274   std::sort(words.begin(), words.end());
 275   words.erase(std::unique(words.begin(), words.end()), words.end());
 276
 277   // Now create a map from (first character) to (words beginning with that
 278   // character).  We insert in reverse lexicographical order and rely on the
 279   // multimap preserving insertion order for values with the same key.  (This
 280   // is mandated in C++11, and part of that decision was based on a survey of
 281   // existing implementations that found that it was already true everywhere.)
 282   std::reverse(words.begin(), words.end());
 283   for (std::vector<base::string16>::const_iterator i(words.begin());
 284        i != words.end(); ++i)
 285     word_map.insert(std::make_pair((*i)[0], *i));
 286   return word_map;
 287 }
 288
 289 // static
 290 ACMatchClassifications ShortcutsProvider::ClassifyAllMatchesInString(
 291     const base::string16& find_text,
 292     const WordMap& find_words,
 293     const base::string16& text,
 294     const ACMatchClassifications& original_class) {
 295   DCHECK(!find_text.empty());
 296   DCHECK(!find_words.empty());
 297
 298   // The code below assumes |text| is nonempty and therefore the resulting
 299   // classification vector should always be nonempty as well.  Returning early
 300   // if |text| is empty assures we'll return the (correct) empty vector rather
 301   // than a vector with a single (0, NONE) match.
 302   if (text.empty())
 303     return original_class;
 304
 305   // First check whether |text| begins with |find_text| and mark that whole
 306   // section as a match if so.
 307   base::string16 text_lowercase(base::i18n::ToLower(text));
 308   ACMatchClassifications match_class;
 309   size_t last_position = 0;
 310   if (StartsWith(text_lowercase, find_text, true)) {
 311     match_class.push_back(
 312         ACMatchClassification(0, ACMatchClassification::MATCH));
 313     last_position = find_text.length();
 314     // If |text_lowercase| is actually equal to |find_text|, we don't need to
 315     // (and in fact shouldn't) put a trailing NONE classification after the end
 316     // of the string.
 317     if (last_position < text_lowercase.length()) {
 318       match_class.push_back(
 319           ACMatchClassification(last_position, ACMatchClassification::NONE));
 320     }
 321   } else {
 322     // |match_class| should start at position 0.  If the first matching word is
 323     // found at position 0, this will be popped from the vector further down.
 324     match_class.push_back(
 325         ACMatchClassification(0, ACMatchClassification::NONE));
 326   }
 327
 328   // Now, starting with |last_position|, check each character in
 329   // |text_lowercase| to see if we have words starting with that character in
 330   // |find_words|.  If so, check each of them to see if they match the portion
 331   // of |text_lowercase| beginning with |last_position|.  Accept the first
 332   // matching word found (which should be the longest possible match at this
 333   // location, given the construction of |find_words|) and add a MATCH region to
 334   // |match_class|, moving |last_position| to be after the matching word.  If we
 335   // found no matching words, move to the next character and repeat.
 336   while (last_position < text_lowercase.length()) {
 337     std::pair<WordMap::const_iterator, WordMap::const_iterator> range(
 338         find_words.equal_range(text_lowercase[last_position]));
 339     size_t next_character = last_position + 1;
 340     for (WordMap::const_iterator i(range.first); i != range.second; ++i) {
 341       const base::string16& word = i->second;
 342       size_t word_end = last_position + word.length();
 343       if ((word_end <= text_lowercase.length()) &&
 344           !text_lowercase.compare(last_position, word.length(), word)) {
 345         // Collapse adjacent ranges into one.
 346         if (match_class.back().offset == last_position)
 347           match_class.pop_back();
 348
 349         AutocompleteMatch::AddLastClassificationIfNecessary(&match_class,
 350             last_position, ACMatchClassification::MATCH);
 351         if (word_end < text_lowercase.length()) {
 352           match_class.push_back(
 353               ACMatchClassification(word_end, ACMatchClassification::NONE));
 354         }
 355         last_position = word_end;
 356         break;
 357       }
 358     }
 359     last_position = std::max(last_position, next_character);
 360   }
 361
 362   return AutocompleteMatch::MergeClassifications(original_class, match_class);
 363 }
 364
 365 ShortcutsBackend::ShortcutMap::const_iterator
 366     ShortcutsProvider::FindFirstMatch(const base::string16& keyword,
 367                                       ShortcutsBackend* backend) {
 368   DCHECK(backend);
 369   ShortcutsBackend::ShortcutMap::const_iterator it =
 370       backend->shortcuts_map().lower_bound(keyword);
 371   // Lower bound not necessarily matches the keyword, check for item pointed by
 372   // the lower bound iterator to at least start with keyword.
 373   return ((it == backend->shortcuts_map().end()) ||
 374     StartsWith(it->first, keyword, true)) ? it :
 375     backend->shortcuts_map().end();
 376 }
 377
 378 int ShortcutsProvider::CalculateScore(
 379     const base::string16& terms,
 380     const history::ShortcutsDatabase::Shortcut& shortcut,
 381     int max_relevance) {
 382   DCHECK(!terms.empty());
 383   DCHECK_LE(terms.length(), shortcut.text.length());
 384
 385   // The initial score is based on how much of the shortcut the user has typed.
 386   // Using the square root of the typed fraction boosts the base score rapidly
 387   // as characters are typed, compared with simply using the typed fraction
 388   // directly. This makes sense since the first characters typed are much more
 389   // important for determining how likely it is a user wants a particular
 390   // shortcut than are the remaining continued characters.
 391   double base_score = max_relevance *
 392       sqrt(static_cast<double>(terms.length()) / shortcut.text.length());
 393
 394   // Then we decay this by half each week.
 395   const double kLn2 = 0.6931471805599453;
 396   base::TimeDelta time_passed = base::Time::Now() - shortcut.last_access_time;
 397   // Clamp to 0 in case time jumps backwards (e.g. due to DST).
 398   double decay_exponent = std::max(0.0, kLn2 * static_cast<double>(
 399       time_passed.InMicroseconds()) / base::Time::kMicrosecondsPerWeek);
 400
 401   // We modulate the decay factor based on how many times the shortcut has been
 402   // used. Newly created shortcuts decay at full speed; otherwise, decaying by
 403   // half takes |n| times as much time, where n increases by
 404   // (1.0 / each 5 additional hits), up to a maximum of 5x as long.
 405   const double kMaxDecaySpeedDivisor = 5.0;
 406   const double kNumUsesPerDecaySpeedDivisorIncrement = 5.0;
 407   double decay_divisor = std::min(kMaxDecaySpeedDivisor,
 408       (shortcut.number_of_hits + kNumUsesPerDecaySpeedDivisorIncrement - 1) /
 409       kNumUsesPerDecaySpeedDivisorIncrement);
 410
 411   return static_cast<int>((base_score / exp(decay_exponent / decay_divisor)) +
 412       0.5);
 413 }