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      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/ui/webui/ntp/suggestions_combiner.h"
      6 
      7 #include <algorithm>
      8 
      9 #include "base/values.h"
     10 #include "chrome/browser/profiles/profile.h"
     11 #include "chrome/browser/ui/browser.h"
     12 #include "chrome/browser/ui/browser_iterator.h"
     13 #include "chrome/browser/ui/tabs/tab_strip_model.h"
     14 #include "chrome/browser/ui/webui/ntp/suggestions_page_handler.h"
     15 #include "chrome/browser/ui/webui/ntp/suggestions_source.h"
     16 #include "content/public/browser/web_contents.h"
     17 
     18 namespace {
     19 
     20 static const size_t kSuggestionsCount = 8;
     21 
     22 }  // namespace
     23 
     24 SuggestionsCombiner::SuggestionsCombiner(
     25     SuggestionsCombiner::Delegate* delegate,
     26     Profile* profile)
     27     : sources_fetching_count_(0),
     28       delegate_(delegate),
     29       suggestions_count_(kSuggestionsCount),
     30       page_values_(new base::ListValue()),
     31       debug_enabled_(false),
     32       profile_(profile) {
     33 }
     34 
     35 SuggestionsCombiner::~SuggestionsCombiner() {
     36 }
     37 
     38 void SuggestionsCombiner::AddSource(SuggestionsSource* source) {
     39   source->SetCombiner(this);
     40   source->SetDebug(debug_enabled_);
     41   sources_.push_back(source);
     42 }
     43 
     44 void SuggestionsCombiner::EnableDebug(bool enable) {
     45   debug_enabled_ = enable;
     46   for (size_t i = 0; i < sources_.size(); ++i) {
     47     sources_[i]->SetDebug(enable);
     48   }
     49 }
     50 
     51 void SuggestionsCombiner::FetchItems(Profile* profile) {
     52   sources_fetching_count_ = sources_.size();
     53   for (size_t i = 0; i < sources_.size(); ++i) {
     54     sources_[i]->FetchItems(profile);
     55   }
     56 }
     57 
     58 base::ListValue* SuggestionsCombiner::GetPageValues() {
     59   return page_values_.get();
     60 }
     61 
     62 void SuggestionsCombiner::OnItemsReady() {
     63   DCHECK_GT(sources_fetching_count_, 0);
     64   sources_fetching_count_--;
     65   if (sources_fetching_count_ == 0) {
     66     FillPageValues();
     67     delegate_->OnSuggestionsReady();
     68   }
     69 }
     70 
     71 void SuggestionsCombiner::SetSuggestionsCount(size_t suggestions_count) {
     72   suggestions_count_ = suggestions_count;
     73 }
     74 
     75 void SuggestionsCombiner::FillPageValues() {
     76   int total_weight = 0;
     77   for (size_t i = 0; i < sources_.size(); ++i)
     78     total_weight += sources_[i]->GetWeight();
     79   DCHECK_GT(total_weight, 0);
     80 
     81   page_values_.reset(new base::ListValue());
     82 
     83   // Evaluate how many items to obtain from each source. We use error diffusion
     84   // to ensure that we get the total desired number of items.
     85   int error = 0;
     86 
     87   // Holds the index at which the next item should be added for each source.
     88   std::vector<size_t> next_item_index_for_source;
     89   next_item_index_for_source.reserve(sources_.size());
     90   for (size_t i = 0; i < sources_.size(); ++i) {
     91     int numerator = sources_[i]->GetWeight() * suggestions_count_ + error;
     92     error = numerator % total_weight;
     93     int item_count = std::min(numerator / total_weight,
     94         sources_[i]->GetItemCount());
     95 
     96     for (int j = 0; j < item_count; ++j)
     97       page_values_->Append(sources_[i]->PopItem());
     98     next_item_index_for_source.push_back(page_values_->GetSize());
     99   }
    100 
    101   // Fill in extra items, prioritizing the first source.
    102   base::DictionaryValue* item;
    103   // Rather than updating |next_item_index_for_source| we keep track of the
    104   // number of extra items that were added and offset indices by that much.
    105   size_t extra_items_added = 0;
    106   for (size_t i = 0; i < sources_.size() &&
    107       page_values_->GetSize() < suggestions_count_; ++i) {
    108 
    109     size_t index = next_item_index_for_source[i] + extra_items_added;
    110     while (page_values_->GetSize() < suggestions_count_ &&
    111         (item = sources_[i]->PopItem())) {
    112       page_values_->Insert(index++, item);
    113       extra_items_added++;
    114     }
    115   }
    116 
    117   // Add page value information common to all sources.
    118   for (size_t i = 0; i < page_values_->GetSize(); i++) {
    119     base::DictionaryValue* page_value;
    120     if (page_values_->GetDictionary(i, &page_value))
    121       AddExtendedInformation(page_value);
    122   }
    123 }
    124 
    125 void SuggestionsCombiner::AddExtendedInformation(
    126     base::DictionaryValue* page_value) {
    127   if (debug_enabled_) {
    128     std::string url_string;
    129     if (page_value->GetString("url", &url_string)) {
    130       GURL url(url_string);
    131       page_value->SetBoolean("already_open", IsUrlAlreadyOpen(url));
    132     }
    133   }
    134 }
    135 
    136 bool SuggestionsCombiner::IsUrlAlreadyOpen(const GURL &url) {
    137   for (chrome::BrowserIterator it; !it.done(); it.Next()) {
    138     const Browser* browser = *it;
    139     if (browser->profile()->IsOffTheRecord() ||
    140         !browser->profile()->IsSameProfile(profile_))
    141       continue;
    142 
    143     for (int i = 0; i < browser->tab_strip_model()->count(); i++) {
    144       const content::WebContents* tab =
    145           browser->tab_strip_model()->GetWebContentsAt(i);
    146       if (tab->GetURL() == url)
    147         return true;
    148     }
    149   }
    150   return false;
    151 }
    152