chrome/browser/ui/app_list/search/mixer.cc

   1 // Copyright 2013 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/ui/app_list/search/mixer.h"
   6
   7 #include <algorithm>
   8 #include <set>
   9 #include <string>
  10 #include <vector>
  11
  12 #include "chrome/browser/ui/app_list/search/chrome_search_result.h"
  13 #include "chrome/browser/ui/app_list/search/search_provider.h"
  14
  15 namespace app_list {
  16
  17 namespace {
  18
  19 // Maximum number of results to show.
  20 const size_t kMaxResults = 6;
  21 const size_t kMaxMainGroupResults = 4;
  22 const size_t kMaxWebstoreResults = 2;
  23
  24 // A value to indicate no max number of results limit.
  25 const size_t kNoMaxResultsLimit = 0;
  26
  27 // Used for sorting and mixing results.
  28 struct SortData {
  29   SortData()
  30       : result(NULL),
  31         score(0.0) {
  32   }
  33   SortData(ChromeSearchResult* result, double score)
  34       : result(result),
  35         score(score) {
  36   }
  37
  38   bool operator<(const SortData& other) const {
  39     // This data precedes (less than) |other| if it has higher score.
  40     return score > other.score;
  41   }
  42
  43   ChromeSearchResult* result;  // Not owned.
  44   double score;
  45 };
  46 typedef std::vector<SortData> SortedResults;
  47
  48 // Removes duplicates from |results|.
  49 void RemoveDuplicates(SortedResults* results) {
  50   SortedResults final;
  51   final.reserve(results->size());
  52
  53   std::set<std::string> id_set;
  54   for (SortedResults::iterator it = results->begin();
  55        it != results->end();
  56        ++it) {
  57     const std::string& id = it->result->id();
  58     if (id_set.find(id) != id_set.end())
  59       continue;
  60
  61     id_set.insert(id);
  62     final.push_back(*it);
  63   }
  64
  65   results->swap(final);
  66 }
  67
  68 // Publishes the given |results| to |ui_results|. Reuse existing ones to avoid
  69 // flickering.
  70 void Publish(const SortedResults& results,
  71              AppListModel::SearchResults* ui_results) {
  72   for (size_t i = 0; i < results.size(); ++i) {
  73     ChromeSearchResult* result = results[i].result;
  74
  75     ChromeSearchResult* ui_result = i < ui_results->item_count() ?
  76         static_cast<ChromeSearchResult*>(ui_results->GetItemAt(i)) : NULL;
  77     if (ui_result && ui_result->id() == result->id()) {
  78       ui_result->set_title(result->title());
  79       ui_result->set_title_tags(result->title_tags());
  80       ui_result->set_details(result->details());
  81       ui_result->set_details_tags(result->details_tags());
  82       ui_results->NotifyItemsChanged(i, 1);
  83     } else {
  84       if (ui_result)
  85         ui_results->DeleteAt(i);
  86       ui_results->AddAt(i, result->Duplicate().release());
  87     }
  88   }
  89
  90   while (ui_results->item_count() > results.size())
  91     ui_results->DeleteAt(ui_results->item_count() - 1);
  92 }
  93
  94 }  // namespace
  95
  96 // Used to group relevant providers together fox mixing their results.
  97 class Mixer::Group {
  98  public:
  99   Group(size_t max_results, double boost)
 100       : max_results_(max_results),
 101         boost_(boost) {
 102   }
 103   ~Group() {}
 104
 105   void AddProvider(SearchProvider* provider) {
 106     providers_.push_back(provider);
 107   }
 108
 109   void FetchResults(const KnownResults& known_results) {
 110     results_.clear();
 111
 112     for (Providers::const_iterator provider_it = providers_.begin();
 113          provider_it != providers_.end();
 114          ++provider_it) {
 115       for (SearchProvider::Results::const_iterator
 116                result_it = (*provider_it)->results().begin();
 117                result_it != (*provider_it)->results().end();
 118                ++result_it) {
 119         DCHECK_GE((*result_it)->relevance(), 0.0);
 120         DCHECK_LE((*result_it)->relevance(), 1.0);
 121         DCHECK(!(*result_it)->id().empty());
 122
 123         double boost = boost_;
 124         KnownResults::const_iterator known_it =
 125             known_results.find((*result_it)->id());
 126         if (known_it != known_results.end()) {
 127           switch (known_it->second) {
 128             case PERFECT_PRIMARY:
 129               boost = 4.0;
 130               break;
 131             case PREFIX_PRIMARY:
 132               boost = 3.75;
 133               break;
 134             case PERFECT_SECONDARY:
 135               boost = 3.25;
 136               break;
 137             case PREFIX_SECONDARY:
 138               boost = 3.0;
 139               break;
 140             case UNKNOWN_RESULT:
 141               NOTREACHED() << "Unknown result in KnownResults?";
 142               break;
 143           }
 144         }
 145
 146         results_.push_back(
 147             SortData(*result_it, (*result_it)->relevance() + boost));
 148       }
 149     }
 150
 151     std::sort(results_.begin(), results_.end());
 152     if (max_results_ != kNoMaxResultsLimit && results_.size() > max_results_)
 153       results_.resize(max_results_);
 154   }
 155
 156   const SortedResults& results() const { return results_; }
 157
 158  private:
 159   typedef std::vector<SearchProvider*> Providers;
 160   const size_t max_results_;
 161   const double boost_;
 162
 163   Providers providers_;  // Not owned.
 164   SortedResults results_;
 165
 166   DISALLOW_COPY_AND_ASSIGN(Group);
 167 };
 168
 169 Mixer::Mixer(AppListModel::SearchResults* ui_results)
 170     : ui_results_(ui_results) {}
 171 Mixer::~Mixer() {}
 172
 173 void Mixer::Init() {
 174   groups_.push_back(new Group(kMaxMainGroupResults, 2.0));
 175   groups_.push_back(new Group(kNoMaxResultsLimit, 1.0));
 176   groups_.push_back(new Group(kMaxWebstoreResults, 0.0));
 177 }
 178
 179 void Mixer::AddProviderToGroup(GroupId group, SearchProvider* provider) {
 180   size_t group_index = static_cast<size_t>(group);
 181   groups_[group_index]->AddProvider(provider);
 182 }
 183
 184 void Mixer::MixAndPublish(const KnownResults& known_results) {
 185   FetchResults(known_results);
 186
 187   SortedResults results;
 188   results.reserve(kMaxResults);
 189
 190   // Adds main group and web store results first.
 191   results.insert(results.end(),
 192                  groups_[MAIN_GROUP]->results().begin(),
 193                  groups_[MAIN_GROUP]->results().end());
 194   results.insert(results.end(),
 195                  groups_[WEBSTORE_GROUP]->results().begin(),
 196                  groups_[WEBSTORE_GROUP]->results().end());
 197
 198   // Collapse duplicate apps from local and web store.
 199   RemoveDuplicates(&results);
 200
 201   DCHECK_GE(kMaxResults, results.size());
 202   size_t remaining_slots = kMaxResults - results.size();
 203
 204   // Reserves at least one slot for the omnibox result. If there is no available
 205   // slot for omnibox results, removes the last one from web store.
 206   const size_t omnibox_results = groups_[OMNIBOX_GROUP]->results().size();
 207   if (!remaining_slots && omnibox_results)
 208     results.pop_back();
 209
 210   remaining_slots = std::min(kMaxResults - results.size(), omnibox_results);
 211   results.insert(results.end(),
 212                  groups_[OMNIBOX_GROUP]->results().begin(),
 213                  groups_[OMNIBOX_GROUP]->results().begin() + remaining_slots);
 214
 215   std::sort(results.begin(), results.end());
 216   RemoveDuplicates(&results);
 217   if (results.size() > kMaxResults)
 218     results.resize(kMaxResults);
 219
 220   Publish(results, ui_results_);
 221 }
 222
 223 void Mixer::FetchResults(const KnownResults& known_results) {
 224   for (Groups::iterator group_it = groups_.begin();
 225        group_it != groups_.end();
 226        ++group_it) {
 227     (*group_it)->FetchResults(known_results);
 228   }
 229 }
 230
 231 }  // namespace app_list