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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 
SuggestionsCombiner(SuggestionsCombiner::Delegate * delegate,Profile * profile)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 
~SuggestionsCombiner()35 SuggestionsCombiner::~SuggestionsCombiner() {
36 }
37 
AddSource(SuggestionsSource * source)38 void SuggestionsCombiner::AddSource(SuggestionsSource* source) {
39   source->SetCombiner(this);
40   source->SetDebug(debug_enabled_);
41   sources_.push_back(source);
42 }
43 
EnableDebug(bool enable)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 
FetchItems(Profile * profile)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 
GetPageValues()58 base::ListValue* SuggestionsCombiner::GetPageValues() {
59   return page_values_.get();
60 }
61 
OnItemsReady()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 
SetSuggestionsCount(size_t suggestions_count)71 void SuggestionsCombiner::SetSuggestionsCount(size_t suggestions_count) {
72   suggestions_count_ = suggestions_count;
73 }
74 
FillPageValues()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   // Rather than updating |next_item_index_for_source| we keep track of the
103   // number of extra items that were added and offset indices by that much.
104   size_t extra_items_added = 0;
105   for (size_t i = 0; i < sources_.size() &&
106       page_values_->GetSize() < suggestions_count_; ++i) {
107 
108     size_t index = next_item_index_for_source[i] + extra_items_added;
109     while (page_values_->GetSize() < suggestions_count_) {
110       base::DictionaryValue* item = sources_[i]->PopItem();
111       if (!item)
112         break;
113       page_values_->Insert(index++, item);
114       extra_items_added++;
115     }
116   }
117 
118   // Add page value information common to all sources.
119   for (size_t i = 0; i < page_values_->GetSize(); i++) {
120     base::DictionaryValue* page_value;
121     if (page_values_->GetDictionary(i, &page_value))
122       AddExtendedInformation(page_value);
123   }
124 }
125 
AddExtendedInformation(base::DictionaryValue * page_value)126 void SuggestionsCombiner::AddExtendedInformation(
127     base::DictionaryValue* page_value) {
128   if (debug_enabled_) {
129     std::string url_string;
130     if (page_value->GetString("url", &url_string)) {
131       GURL url(url_string);
132       page_value->SetBoolean("already_open", IsUrlAlreadyOpen(url));
133     }
134   }
135 }
136 
IsUrlAlreadyOpen(const GURL & url)137 bool SuggestionsCombiner::IsUrlAlreadyOpen(const GURL &url) {
138   for (chrome::BrowserIterator it; !it.done(); it.Next()) {
139     const Browser* browser = *it;
140     if (browser->profile()->IsOffTheRecord() ||
141         !browser->profile()->IsSameProfile(profile_))
142       continue;
143 
144     for (int i = 0; i < browser->tab_strip_model()->count(); i++) {
145       const content::WebContents* tab =
146           browser->tab_strip_model()->GetWebContentsAt(i);
147       if (tab->GetURL() == url)
148         return true;
149     }
150   }
151   return false;
152 }
153