root/chrome/browser/autocomplete/base_search_provider.cc

/* [<][>][^][v][top][bottom][index][help] */

DEFINITIONS

This source file includes following definitions.
  1. GetAutocompleteMatchType
  2. OnURLFetchComplete
  3. suggest_results_pending_
  4. ShouldPrefetch
  5. CreateSearchSuggestion
  6. Stop
  7. DeleteMatch
  8. AddProviderInfo
  9. relevance_from_server_
  10. should_prefetch_
  11. ClassifyMatchContents
  12. IsInlineable
  13. CalculateRelevance
  14. description_
  15. CalculateAndClassifyMatchContents
  16. IsInlineable
  17. CalculateRelevance
  18. Clear
  19. HasServerProvidedScores
  20. CreateSearchSuggestion
  21. DeserializeJsonData
  22. ZeroSuggestEnabled
  23. CanSendURL
  24. OnURLFetchComplete
  25. AddMatchToMap
  26. ParseSuggestResults
  27. SortResults
  28. DeleteMatchFromMatches
  29. OnDeletionComplete

// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "chrome/browser/autocomplete/base_search_provider.h"

#include "base/i18n/case_conversion.h"
#include "base/i18n/icu_string_conversions.h"
#include "base/json/json_string_value_serializer.h"
#include "base/prefs/pref_service.h"
#include "base/strings/string_util.h"
#include "base/strings/utf_string_conversions.h"
#include "chrome/browser/autocomplete/autocomplete_provider_listener.h"
#include "chrome/browser/autocomplete/url_prefix.h"
#include "chrome/browser/history/history_service.h"
#include "chrome/browser/history/history_service_factory.h"
#include "chrome/browser/omnibox/omnibox_field_trial.h"
#include "chrome/browser/profiles/profile.h"
#include "chrome/browser/search/instant_service.h"
#include "chrome/browser/search/instant_service_factory.h"
#include "chrome/browser/search/search.h"
#include "chrome/browser/search_engines/template_url.h"
#include "chrome/browser/search_engines/template_url_prepopulate_data.h"
#include "chrome/browser/sync/profile_sync_service.h"
#include "chrome/browser/sync/profile_sync_service_factory.h"
#include "chrome/common/net/url_fixer_upper.h"
#include "chrome/common/pref_names.h"
#include "components/sync_driver/sync_prefs.h"
#include "content/public/common/url_constants.h"
#include "net/base/escape.h"
#include "net/base/net_util.h"
#include "net/base/registry_controlled_domains/registry_controlled_domain.h"
#include "net/http/http_response_headers.h"
#include "net/url_request/url_fetcher_delegate.h"
#include "url/gurl.h"

namespace {

AutocompleteMatchType::Type GetAutocompleteMatchType(const std::string& type) {
  if (type == "ENTITY")
    return AutocompleteMatchType::SEARCH_SUGGEST_ENTITY;
  if (type == "INFINITE")
    return AutocompleteMatchType::SEARCH_SUGGEST_INFINITE;
  if (type == "PERSONALIZED_QUERY")
    return AutocompleteMatchType::SEARCH_SUGGEST_PERSONALIZED;
  if (type == "PROFILE")
    return AutocompleteMatchType::SEARCH_SUGGEST_PROFILE;
  return AutocompleteMatchType::SEARCH_SUGGEST;
}

} // namespace

// SuggestionDeletionHandler -------------------------------------------------

// This class handles making requests to the server in order to delete
// personalized suggestions.
class SuggestionDeletionHandler : public net::URLFetcherDelegate {
 public:
  typedef base::Callback<void(bool, SuggestionDeletionHandler*)>
      DeletionCompletedCallback;

  SuggestionDeletionHandler(
      const std::string& deletion_url,
      Profile* profile,
      const DeletionCompletedCallback& callback);

  virtual ~SuggestionDeletionHandler();

 private:
  // net::URLFetcherDelegate:
  virtual void OnURLFetchComplete(const net::URLFetcher* source) OVERRIDE;

  scoped_ptr<net::URLFetcher> deletion_fetcher_;
  DeletionCompletedCallback callback_;

  DISALLOW_COPY_AND_ASSIGN(SuggestionDeletionHandler);
};

SuggestionDeletionHandler::SuggestionDeletionHandler(
    const std::string& deletion_url,
    Profile* profile,
    const DeletionCompletedCallback& callback) : callback_(callback) {
  GURL url(deletion_url);
  DCHECK(url.is_valid());

  deletion_fetcher_.reset(net::URLFetcher::Create(
      BaseSearchProvider::kDeletionURLFetcherID,
      url,
      net::URLFetcher::GET,
      this));
  deletion_fetcher_->SetRequestContext(profile->GetRequestContext());
  deletion_fetcher_->Start();
};

SuggestionDeletionHandler::~SuggestionDeletionHandler() {
};

void SuggestionDeletionHandler::OnURLFetchComplete(
    const net::URLFetcher* source) {
  DCHECK(source == deletion_fetcher_.get());
  callback_.Run(
      source->GetStatus().is_success() && (source->GetResponseCode() == 200),
      this);
};

// BaseSearchProvider ---------------------------------------------------------

// static
const int BaseSearchProvider::kDefaultProviderURLFetcherID = 1;
const int BaseSearchProvider::kKeywordProviderURLFetcherID = 2;
const int BaseSearchProvider::kDeletionURLFetcherID = 3;

BaseSearchProvider::BaseSearchProvider(AutocompleteProviderListener* listener,
                                       Profile* profile,
                                       AutocompleteProvider::Type type)
    : AutocompleteProvider(listener, profile, type),
      field_trial_triggered_(false),
      field_trial_triggered_in_session_(false),
      suggest_results_pending_(0) {
}

// static
bool BaseSearchProvider::ShouldPrefetch(const AutocompleteMatch& match) {
  return match.GetAdditionalInfo(kShouldPrefetchKey) == kTrue;
}

// static
AutocompleteMatch BaseSearchProvider::CreateSearchSuggestion(
    const base::string16& suggestion,
    AutocompleteMatchType::Type type,
    bool from_keyword_provider,
    const TemplateURL* template_url) {
  return CreateSearchSuggestion(
      NULL, AutocompleteInput(), BaseSearchProvider::SuggestResult(
          suggestion, type, suggestion, base::string16(), base::string16(),
          std::string(), std::string(), from_keyword_provider, 0, false, false,
          base::string16()),
      template_url, 0, 0, false);
}

void BaseSearchProvider::Stop(bool clear_cached_results) {
  StopSuggest();
  done_ = true;

  if (clear_cached_results)
    ClearAllResults();
}

void BaseSearchProvider::DeleteMatch(const AutocompleteMatch& match) {
  DCHECK(match.deletable);

  if (!match.GetAdditionalInfo(BaseSearchProvider::kDeletionUrlKey).empty()) {
    deletion_handlers_.push_back(new SuggestionDeletionHandler(
        match.GetAdditionalInfo(BaseSearchProvider::kDeletionUrlKey),
        profile_,
        base::Bind(&BaseSearchProvider::OnDeletionComplete,
                   base::Unretained(this))));
  }

  HistoryService* const history_service =
      HistoryServiceFactory::GetForProfile(profile_, Profile::EXPLICIT_ACCESS);
  TemplateURL* template_url = match.GetTemplateURL(profile_, false);
  // This may be NULL if the template corresponding to the keyword has been
  // deleted or there is no keyword set.
  if (template_url != NULL) {
    history_service->DeleteMatchingURLsForKeyword(template_url->id(),
                                                  match.contents);
  }

  // Immediately update the list of matches to show the match was deleted,
  // regardless of whether the server request actually succeeds.
  DeleteMatchFromMatches(match);
}

void BaseSearchProvider::AddProviderInfo(ProvidersInfo* provider_info) const {
  provider_info->push_back(metrics::OmniboxEventProto_ProviderInfo());
  metrics::OmniboxEventProto_ProviderInfo& new_entry = provider_info->back();
  new_entry.set_provider(AsOmniboxEventProviderType());
  new_entry.set_provider_done(done_);
  std::vector<uint32> field_trial_hashes;
  OmniboxFieldTrial::GetActiveSuggestFieldTrialHashes(&field_trial_hashes);
  for (size_t i = 0; i < field_trial_hashes.size(); ++i) {
    if (field_trial_triggered_)
      new_entry.mutable_field_trial_triggered()->Add(field_trial_hashes[i]);
    if (field_trial_triggered_in_session_) {
      new_entry.mutable_field_trial_triggered_in_session()->Add(
          field_trial_hashes[i]);
    }
  }
}

// static
const char BaseSearchProvider::kRelevanceFromServerKey[] =
    "relevance_from_server";
const char BaseSearchProvider::kShouldPrefetchKey[] = "should_prefetch";
const char BaseSearchProvider::kSuggestMetadataKey[] = "suggest_metadata";
const char BaseSearchProvider::kDeletionUrlKey[] = "deletion_url";
const char BaseSearchProvider::kTrue[] = "true";
const char BaseSearchProvider::kFalse[] = "false";

BaseSearchProvider::~BaseSearchProvider() {}

// BaseSearchProvider::Result --------------------------------------------------

BaseSearchProvider::Result::Result(bool from_keyword_provider,
                                   int relevance,
                                   bool relevance_from_server)
    : from_keyword_provider_(from_keyword_provider),
      relevance_(relevance),
      relevance_from_server_(relevance_from_server) {}

BaseSearchProvider::Result::~Result() {}

// BaseSearchProvider::SuggestResult -------------------------------------------

BaseSearchProvider::SuggestResult::SuggestResult(
    const base::string16& suggestion,
    AutocompleteMatchType::Type type,
    const base::string16& match_contents,
    const base::string16& match_contents_prefix,
    const base::string16& annotation,
    const std::string& suggest_query_params,
    const std::string& deletion_url,
    bool from_keyword_provider,
    int relevance,
    bool relevance_from_server,
    bool should_prefetch,
    const base::string16& input_text)
    : Result(from_keyword_provider, relevance, relevance_from_server),
      suggestion_(suggestion),
      type_(type),
      match_contents_prefix_(match_contents_prefix),
      annotation_(annotation),
      suggest_query_params_(suggest_query_params),
      deletion_url_(deletion_url),
      should_prefetch_(should_prefetch) {
  match_contents_ = match_contents;
  DCHECK(!match_contents_.empty());
  ClassifyMatchContents(true, input_text);
}

BaseSearchProvider::SuggestResult::~SuggestResult() {}

void BaseSearchProvider::SuggestResult::ClassifyMatchContents(
    const bool allow_bolding_all,
    const base::string16& input_text) {
  if (input_text.empty()) {
    // In case of zero-suggest results, do not highlight matches.
    match_contents_class_.push_back(
        ACMatchClassification(0, ACMatchClassification::NONE));
    return;
  }

  base::string16 lookup_text = input_text;
  if (type_ == AutocompleteMatchType::SEARCH_SUGGEST_INFINITE) {
    const size_t contents_index =
        suggestion_.length() - match_contents_.length();
    // Ensure the query starts with the input text, and ends with the match
    // contents, and the input text has an overlap with contents.
    if (StartsWith(suggestion_, input_text, true) &&
        EndsWith(suggestion_, match_contents_, true) &&
        (input_text.length() > contents_index)) {
      lookup_text = input_text.substr(contents_index);
    }
  }
  size_t lookup_position = match_contents_.find(lookup_text);
  if (!allow_bolding_all && (lookup_position == base::string16::npos)) {
    // Bail if the code below to update the bolding would bold the whole
    // string.  Note that the string may already be entirely bolded; if
    // so, leave it as is.
    return;
  }
  match_contents_class_.clear();
  // We do intra-string highlighting for suggestions - the suggested segment
  // will be highlighted, e.g. for input_text = "you" the suggestion may be
  // "youtube", so we'll bold the "tube" section: you*tube*.
  if (input_text != match_contents_) {
    if (lookup_position == base::string16::npos) {
      // The input text is not a substring of the query string, e.g. input
      // text is "slasdot" and the query string is "slashdot", so we bold the
      // whole thing.
      match_contents_class_.push_back(
          ACMatchClassification(0, ACMatchClassification::MATCH));
    } else {
      // We don't iterate over the string here annotating all matches because
      // it looks odd to have every occurrence of a substring that may be as
      // short as a single character highlighted in a query suggestion result,
      // e.g. for input text "s" and query string "southwest airlines", it
      // looks odd if both the first and last s are highlighted.
      if (lookup_position != 0) {
        match_contents_class_.push_back(
            ACMatchClassification(0, ACMatchClassification::MATCH));
      }
      match_contents_class_.push_back(
          ACMatchClassification(lookup_position, ACMatchClassification::NONE));
      size_t next_fragment_position = lookup_position + lookup_text.length();
      if (next_fragment_position < match_contents_.length()) {
        match_contents_class_.push_back(ACMatchClassification(
            next_fragment_position, ACMatchClassification::MATCH));
      }
    }
  } else {
    // Otherwise, match_contents_ is a verbatim (what-you-typed) match, either
    // for the default provider or a keyword search provider.
    match_contents_class_.push_back(
        ACMatchClassification(0, ACMatchClassification::NONE));
  }
}

bool BaseSearchProvider::SuggestResult::IsInlineable(
    const base::string16& input) const {
  return StartsWith(suggestion_, input, false);
}

int BaseSearchProvider::SuggestResult::CalculateRelevance(
    const AutocompleteInput& input,
    bool keyword_provider_requested) const {
  if (!from_keyword_provider_ && keyword_provider_requested)
    return 100;
  return ((input.type() == AutocompleteInput::URL) ? 300 : 600);
}

// BaseSearchProvider::NavigationResult ----------------------------------------

BaseSearchProvider::NavigationResult::NavigationResult(
    const AutocompleteProvider& provider,
    const GURL& url,
    const base::string16& description,
    bool from_keyword_provider,
    int relevance,
    bool relevance_from_server,
    const base::string16& input_text,
    const std::string& languages)
    : Result(from_keyword_provider, relevance, relevance_from_server),
      url_(url),
      formatted_url_(AutocompleteInput::FormattedStringWithEquivalentMeaning(
          url,
          provider.StringForURLDisplay(url, true, false))),
      description_(description) {
  DCHECK(url_.is_valid());
  CalculateAndClassifyMatchContents(true, input_text, languages);
}

BaseSearchProvider::NavigationResult::~NavigationResult() {}

void BaseSearchProvider::NavigationResult::CalculateAndClassifyMatchContents(
    const bool allow_bolding_nothing,
    const base::string16& input_text,
    const std::string& languages) {
  if (input_text.empty()) {
    // In case of zero-suggest results, do not highlight matches.
    match_contents_class_.push_back(
        ACMatchClassification(0, ACMatchClassification::NONE));
    return;
  }

  // First look for the user's input inside the formatted url as it would be
  // without trimming the scheme, so we can find matches at the beginning of the
  // scheme.
  const URLPrefix* prefix =
      URLPrefix::BestURLPrefix(formatted_url_, input_text);
  size_t match_start = (prefix == NULL) ?
      formatted_url_.find(input_text) : prefix->prefix.length();
  bool trim_http = !AutocompleteInput::HasHTTPScheme(input_text) &&
                   (!prefix || (match_start != 0));
  const net::FormatUrlTypes format_types =
      net::kFormatUrlOmitAll & ~(trim_http ? 0 : net::kFormatUrlOmitHTTP);

  base::string16 match_contents = net::FormatUrl(url_, languages, format_types,
      net::UnescapeRule::SPACES, NULL, NULL, &match_start);
  // If the first match in the untrimmed string was inside a scheme that we
  // trimmed, look for a subsequent match.
  if (match_start == base::string16::npos)
    match_start = match_contents.find(input_text);
  // Update |match_contents_| and |match_contents_class_| if it's allowed.
  if (allow_bolding_nothing || (match_start != base::string16::npos)) {
    match_contents_ = match_contents;
    // Safe if |match_start| is npos; also safe if the input is longer than the
    // remaining contents after |match_start|.
    AutocompleteMatch::ClassifyLocationInString(match_start,
        input_text.length(), match_contents_.length(),
        ACMatchClassification::URL, &match_contents_class_);
  }
}

bool BaseSearchProvider::NavigationResult::IsInlineable(
    const base::string16& input) const {
  return
      URLPrefix::BestURLPrefix(base::UTF8ToUTF16(url_.spec()), input) != NULL;
}

int BaseSearchProvider::NavigationResult::CalculateRelevance(
    const AutocompleteInput& input,
    bool keyword_provider_requested) const {
  return (from_keyword_provider_ || !keyword_provider_requested) ? 800 : 150;
}

// BaseSearchProvider::Results -------------------------------------------------

BaseSearchProvider::Results::Results() : verbatim_relevance(-1) {}

BaseSearchProvider::Results::~Results() {}

void BaseSearchProvider::Results::Clear() {
  suggest_results.clear();
  navigation_results.clear();
  verbatim_relevance = -1;
  metadata.clear();
}

bool BaseSearchProvider::Results::HasServerProvidedScores() const {
  if (verbatim_relevance >= 0)
    return true;

  // Right now either all results of one type will be server-scored or they will
  // all be locally scored, but in case we change this later, we'll just check
  // them all.
  for (SuggestResults::const_iterator i(suggest_results.begin());
       i != suggest_results.end(); ++i) {
    if (i->relevance_from_server())
      return true;
  }
  for (NavigationResults::const_iterator i(navigation_results.begin());
       i != navigation_results.end(); ++i) {
    if (i->relevance_from_server())
      return true;
  }

  return false;
}

// BaseSearchProvider ---------------------------------------------------------

// static
AutocompleteMatch BaseSearchProvider::CreateSearchSuggestion(
    AutocompleteProvider* autocomplete_provider,
    const AutocompleteInput& input,
    const SuggestResult& suggestion,
    const TemplateURL* template_url,
    int accepted_suggestion,
    int omnibox_start_margin,
    bool append_extra_query_params) {
  AutocompleteMatch match(autocomplete_provider, suggestion.relevance(), false,
                          suggestion.type());

  if (!template_url)
    return match;
  match.keyword = template_url->keyword();
  match.contents = suggestion.match_contents();
  match.contents_class = suggestion.match_contents_class();
  if (suggestion.type() == AutocompleteMatchType::SEARCH_SUGGEST_INFINITE) {
    match.RecordAdditionalInfo(
        kACMatchPropertyInputText, base::UTF16ToUTF8(input.text()));
    match.RecordAdditionalInfo(
        kACMatchPropertyContentsPrefix,
        base::UTF16ToUTF8(suggestion.match_contents_prefix()));
    match.RecordAdditionalInfo(
        kACMatchPropertyContentsStartIndex,
        static_cast<int>(
            suggestion.suggestion().length() - match.contents.length()));
  }

  if (!suggestion.annotation().empty())
    match.description = suggestion.annotation();

  // suggestion.match_contents() should have already been collapsed.
  match.allowed_to_be_default_match =
      (base::CollapseWhitespace(input.text(), false) ==
       suggestion.match_contents());

  // When the user forced a query, we need to make sure all the fill_into_edit
  // values preserve that property.  Otherwise, if the user starts editing a
  // suggestion, non-Search results will suddenly appear.
  if (input.type() == AutocompleteInput::FORCED_QUERY)
    match.fill_into_edit.assign(base::ASCIIToUTF16("?"));
  if (suggestion.from_keyword_provider())
    match.fill_into_edit.append(match.keyword + base::char16(' '));
  if (!input.prevent_inline_autocomplete() &&
      StartsWith(suggestion.suggestion(), input.text(), false)) {
    match.inline_autocompletion =
        suggestion.suggestion().substr(input.text().length());
    match.allowed_to_be_default_match = true;
  }
  match.fill_into_edit.append(suggestion.suggestion());

  const TemplateURLRef& search_url = template_url->url_ref();
  DCHECK(search_url.SupportsReplacement());
  match.search_terms_args.reset(
      new TemplateURLRef::SearchTermsArgs(suggestion.suggestion()));
  match.search_terms_args->original_query = input.text();
  match.search_terms_args->accepted_suggestion = accepted_suggestion;
  match.search_terms_args->omnibox_start_margin = omnibox_start_margin;
  match.search_terms_args->suggest_query_params =
      suggestion.suggest_query_params();
  match.search_terms_args->append_extra_query_params =
      append_extra_query_params;
  // This is the destination URL sans assisted query stats.  This must be set
  // so the AutocompleteController can properly de-dupe; the controller will
  // eventually overwrite it before it reaches the user.
  match.destination_url =
      GURL(search_url.ReplaceSearchTerms(*match.search_terms_args.get()));

  // Search results don't look like URLs.
  match.transition = suggestion.from_keyword_provider() ?
      content::PAGE_TRANSITION_KEYWORD : content::PAGE_TRANSITION_GENERATED;

  return match;
}

// static
scoped_ptr<base::Value> BaseSearchProvider::DeserializeJsonData(
    std::string json_data) {
  // The JSON response should be an array.
  for (size_t response_start_index = json_data.find("["), i = 0;
       response_start_index != std::string::npos && i < 5;
       response_start_index = json_data.find("[", 1), i++) {
    // Remove any XSSI guards to allow for JSON parsing.
    if (response_start_index > 0)
      json_data.erase(0, response_start_index);

    JSONStringValueSerializer deserializer(json_data);
    deserializer.set_allow_trailing_comma(true);
    int error_code = 0;
    scoped_ptr<base::Value> data(deserializer.Deserialize(&error_code, NULL));
    if (error_code == 0)
      return data.Pass();
  }
  return scoped_ptr<base::Value>();
}

// static
bool BaseSearchProvider::ZeroSuggestEnabled(
    const GURL& suggest_url,
    const TemplateURL* template_url,
    AutocompleteInput::PageClassification page_classification,
    Profile* profile) {
  if (!OmniboxFieldTrial::InZeroSuggestFieldTrial())
    return false;

  // Make sure we are sending the suggest request through HTTPS to prevent
  // exposing the current page URL or personalized results without encryption.
  if (!suggest_url.SchemeIs(content::kHttpsScheme))
    return false;

  // Don't show zero suggest on the NTP.
  // TODO(hfung): Experiment with showing MostVisited zero suggest on NTP
  // under the conditions described in crbug.com/305366.
  if ((page_classification ==
       AutocompleteInput::INSTANT_NTP_WITH_FAKEBOX_AS_STARTING_FOCUS) ||
      (page_classification ==
       AutocompleteInput::INSTANT_NTP_WITH_OMNIBOX_AS_STARTING_FOCUS))
    return false;

  // Don't run if there's no profile or in incognito mode.
  if (profile == NULL || profile->IsOffTheRecord())
    return false;

  // Don't run if we can't get preferences or search suggest is not enabled.
  PrefService* prefs = profile->GetPrefs();
  if (!prefs->GetBoolean(prefs::kSearchSuggestEnabled))
    return false;

  // Only make the request if we know that the provider supports zero suggest
  // (currently only the prepopulated Google provider).
  if (template_url == NULL || !template_url->SupportsReplacement() ||
      TemplateURLPrepopulateData::GetEngineType(*template_url) !=
      SEARCH_ENGINE_GOOGLE)
    return false;

  return true;
}

// static
bool BaseSearchProvider::CanSendURL(
    const GURL& current_page_url,
    const GURL& suggest_url,
    const TemplateURL* template_url,
    AutocompleteInput::PageClassification page_classification,
    Profile* profile) {
  if (!ZeroSuggestEnabled(suggest_url, template_url, page_classification,
                          profile))
    return false;

  if (!current_page_url.is_valid())
    return false;

  // Only allow HTTP URLs or HTTPS URLs for the same domain as the search
  // provider.
  if ((current_page_url.scheme() != content::kHttpScheme) &&
      ((current_page_url.scheme() != content::kHttpsScheme) ||
       !net::registry_controlled_domains::SameDomainOrHost(
           current_page_url, suggest_url,
           net::registry_controlled_domains::EXCLUDE_PRIVATE_REGISTRIES)))
    return false;

  // Check field trials and settings allow sending the URL on suggest requests.
  ProfileSyncService* service =
      ProfileSyncServiceFactory::GetInstance()->GetForProfile(profile);
  sync_driver::SyncPrefs sync_prefs(profile->GetPrefs());
  if (service == NULL ||
      !service->IsSyncEnabledAndLoggedIn() ||
      !sync_prefs.GetPreferredDataTypes(syncer::UserTypes()).Has(
          syncer::PROXY_TABS) ||
      service->GetEncryptedDataTypes().Has(syncer::SESSIONS))
    return false;

  return true;
}

void BaseSearchProvider::OnURLFetchComplete(const net::URLFetcher* source) {
  DCHECK(!done_);
  suggest_results_pending_--;
  DCHECK_GE(suggest_results_pending_, 0);  // Should never go negative.

  const bool is_keyword = IsKeywordFetcher(source);

  // Ensure the request succeeded and that the provider used is still available.
  // A verbatim match cannot be generated without this provider, causing errors.
  const bool request_succeeded =
      source->GetStatus().is_success() && (source->GetResponseCode() == 200) &&
      GetTemplateURL(is_keyword);

  LogFetchComplete(request_succeeded, is_keyword);

  bool results_updated = false;
  if (request_succeeded) {
    const net::HttpResponseHeaders* const response_headers =
        source->GetResponseHeaders();
    std::string json_data;
    source->GetResponseAsString(&json_data);

    // JSON is supposed to be UTF-8, but some suggest service providers send
    // JSON files in non-UTF-8 encodings.  The actual encoding is usually
    // specified in the Content-Type header field.
    if (response_headers) {
      std::string charset;
      if (response_headers->GetCharset(&charset)) {
        base::string16 data_16;
        // TODO(jungshik): Switch to CodePageToUTF8 after it's added.
        if (base::CodepageToUTF16(json_data, charset.c_str(),
                                  base::OnStringConversionError::FAIL,
                                  &data_16))
          json_data = base::UTF16ToUTF8(data_16);
      }
    }

    scoped_ptr<base::Value> data(DeserializeJsonData(json_data));
    results_updated = data.get() && ParseSuggestResults(
        *data.get(), is_keyword, GetResultsToFill(is_keyword));
  }

  UpdateMatches();
  if (done_ || results_updated)
    listener_->OnProviderUpdate(results_updated);
}

void BaseSearchProvider::AddMatchToMap(const SuggestResult& result,
                                       const std::string& metadata,
                                       int accepted_suggestion,
                                       bool mark_as_deletable,
                                       MatchMap* map) {
  InstantService* instant_service =
      InstantServiceFactory::GetForProfile(profile_);
  // Android and iOS have no InstantService.
  const int omnibox_start_margin = instant_service ?
      instant_service->omnibox_start_margin() : chrome::kDisableStartMargin;

  AutocompleteMatch match = CreateSearchSuggestion(
      this, GetInput(result.from_keyword_provider()), result,
      GetTemplateURL(result.from_keyword_provider()), accepted_suggestion,
      omnibox_start_margin, ShouldAppendExtraParams(result));
  if (!match.destination_url.is_valid())
    return;
  match.search_terms_args->bookmark_bar_pinned =
      profile_->GetPrefs()->GetBoolean(prefs::kShowBookmarkBar);
  match.RecordAdditionalInfo(kRelevanceFromServerKey,
                             result.relevance_from_server() ? kTrue : kFalse);
  match.RecordAdditionalInfo(kShouldPrefetchKey,
                             result.should_prefetch() ? kTrue : kFalse);

  if (!result.deletion_url().empty()) {
    GURL url(match.destination_url.GetOrigin().Resolve(result.deletion_url()));
    if (url.is_valid()) {
      match.RecordAdditionalInfo(kDeletionUrlKey, url.spec());
      match.deletable = true;
    }
  } else if (mark_as_deletable) {
    match.deletable = true;
  }

  // Metadata is needed only for prefetching queries.
  if (result.should_prefetch())
    match.RecordAdditionalInfo(kSuggestMetadataKey, metadata);

  // Try to add |match| to |map|.  If a match for this suggestion is
  // already in |map|, replace it if |match| is more relevant.
  // NOTE: Keep this ToLower() call in sync with url_database.cc.
  MatchKey match_key(
      std::make_pair(base::i18n::ToLower(result.suggestion()),
                     match.search_terms_args->suggest_query_params));
  const std::pair<MatchMap::iterator, bool> i(
       map->insert(std::make_pair(match_key, match)));

  bool should_prefetch = result.should_prefetch();
  if (!i.second) {
    // NOTE: We purposefully do a direct relevance comparison here instead of
    // using AutocompleteMatch::MoreRelevant(), so that we'll prefer "items
    // added first" rather than "items alphabetically first" when the scores
    // are equal. The only case this matters is when a user has results with
    // the same score that differ only by capitalization; because the history
    // system returns results sorted by recency, this means we'll pick the most
    // recent such result even if the precision of our relevance score is too
    // low to distinguish the two.
    if (match.relevance > i.first->second.relevance) {
      match.duplicate_matches.insert(match.duplicate_matches.end(),
                                     i.first->second.duplicate_matches.begin(),
                                     i.first->second.duplicate_matches.end());
      i.first->second.duplicate_matches.clear();
      match.duplicate_matches.push_back(i.first->second);
      i.first->second = match;
    } else {
      i.first->second.duplicate_matches.push_back(match);
      if (match.keyword == i.first->second.keyword) {
        // Old and new matches are from the same search provider. It is okay to
        // record one match's prefetch data onto a different match (for the same
        // query string) for the following reasons:
        // 1. Because the suggest server only sends down a query string from
        // which we construct a URL, rather than sending a full URL, and because
        // we construct URLs from query strings in the same way every time, the
        // URLs for the two matches will be the same. Therefore, we won't end up
        // prefetching something the server didn't intend.
        // 2. Presumably the server sets the prefetch bit on a match it things
        // is sufficiently relevant that the user is likely to choose it.
        // Surely setting the prefetch bit on a match of even higher relevance
        // won't violate this assumption.
        should_prefetch |= ShouldPrefetch(i.first->second);
        i.first->second.RecordAdditionalInfo(kShouldPrefetchKey,
                                             should_prefetch ? kTrue : kFalse);
        if (should_prefetch)
          i.first->second.RecordAdditionalInfo(kSuggestMetadataKey, metadata);
      }
    }
  }
}

bool BaseSearchProvider::ParseSuggestResults(const base::Value& root_val,
                                             bool is_keyword_result,
                                             Results* results) {
  base::string16 query;
  const base::ListValue* root_list = NULL;
  const base::ListValue* results_list = NULL;
  const AutocompleteInput& input = GetInput(is_keyword_result);

  if (!root_val.GetAsList(&root_list) || !root_list->GetString(0, &query) ||
      query != input.text() || !root_list->GetList(1, &results_list))
    return false;

  // 3rd element: Description list.
  const base::ListValue* descriptions = NULL;
  root_list->GetList(2, &descriptions);

  // 4th element: Disregard the query URL list for now.

  // Reset suggested relevance information.
  results->verbatim_relevance = -1;

  // 5th element: Optional key-value pairs from the Suggest server.
  const base::ListValue* types = NULL;
  const base::ListValue* relevances = NULL;
  const base::ListValue* suggestion_details = NULL;
  const base::DictionaryValue* extras = NULL;
  int prefetch_index = -1;
  if (root_list->GetDictionary(4, &extras)) {
    extras->GetList("google:suggesttype", &types);

    // Discard this list if its size does not match that of the suggestions.
    if (extras->GetList("google:suggestrelevance", &relevances) &&
        (relevances->GetSize() != results_list->GetSize()))
      relevances = NULL;
    extras->GetInteger("google:verbatimrelevance",
                       &results->verbatim_relevance);

    // Check if the active suggest field trial (if any) has triggered either
    // for the default provider or keyword provider.
    bool triggered = false;
    extras->GetBoolean("google:fieldtrialtriggered", &triggered);
    field_trial_triggered_ |= triggered;
    field_trial_triggered_in_session_ |= triggered;

    const base::DictionaryValue* client_data = NULL;
    if (extras->GetDictionary("google:clientdata", &client_data) && client_data)
      client_data->GetInteger("phi", &prefetch_index);

    if (extras->GetList("google:suggestdetail", &suggestion_details) &&
        suggestion_details->GetSize() != results_list->GetSize())
      suggestion_details = NULL;

    // Store the metadata that came with the response in case we need to pass it
    // along with the prefetch query to Instant.
    JSONStringValueSerializer json_serializer(&results->metadata);
    json_serializer.Serialize(*extras);
  }

  // Clear the previous results now that new results are available.
  results->suggest_results.clear();
  results->navigation_results.clear();

  base::string16 suggestion;
  std::string type;
  int relevance = GetDefaultResultRelevance();
  // Prohibit navsuggest in FORCED_QUERY mode.  Users wants queries, not URLs.
  const bool allow_navsuggest = input.type() != AutocompleteInput::FORCED_QUERY;
  const std::string languages(
      profile_->GetPrefs()->GetString(prefs::kAcceptLanguages));
  const base::string16& trimmed_input =
      base::CollapseWhitespace(input.text(), false);
  for (size_t index = 0; results_list->GetString(index, &suggestion); ++index) {
    // Google search may return empty suggestions for weird input characters,
    // they make no sense at all and can cause problems in our code.
    if (suggestion.empty())
      continue;

    // Apply valid suggested relevance scores; discard invalid lists.
    if (relevances != NULL && !relevances->GetInteger(index, &relevance))
      relevances = NULL;

    if (types && types->GetString(index, &type) && (type == "NAVIGATION")) {
      // Do not blindly trust the URL coming from the server to be valid.
      GURL url(URLFixerUpper::FixupURL(
          base::UTF16ToUTF8(suggestion), std::string()));
      if (url.is_valid() && allow_navsuggest) {
        base::string16 title;
        if (descriptions != NULL)
          descriptions->GetString(index, &title);
        results->navigation_results.push_back(NavigationResult(
            *this, url, title, is_keyword_result, relevance,
            relevances != NULL, input.text(), languages));
      }
    } else {
      AutocompleteMatchType::Type match_type = GetAutocompleteMatchType(type);
      bool should_prefetch = static_cast<int>(index) == prefetch_index;
      const base::DictionaryValue* suggestion_detail = NULL;
      base::string16 match_contents = suggestion;
      base::string16 match_contents_prefix;
      base::string16 annotation;
      std::string suggest_query_params;
      std::string deletion_url;

      if (suggestion_details) {
        suggestion_details->GetDictionary(index, &suggestion_detail);
        if (suggestion_detail) {
          suggestion_detail->GetString("du", &deletion_url);
          suggestion_detail->GetString("t", &match_contents);
          suggestion_detail->GetString("mp", &match_contents_prefix);
          // Error correction for bad data from server.
          if (match_contents.empty())
            match_contents = suggestion;
          suggestion_detail->GetString("a", &annotation);
          suggestion_detail->GetString("q", &suggest_query_params);
        }
      }

      // TODO(kochi): Improve calculator suggestion presentation.
      results->suggest_results.push_back(SuggestResult(
          base::CollapseWhitespace(suggestion, false), match_type,
          base::CollapseWhitespace(match_contents, false),
          match_contents_prefix, annotation, suggest_query_params,
          deletion_url, is_keyword_result, relevance, relevances != NULL,
          should_prefetch, trimmed_input));
    }
  }
  SortResults(is_keyword_result, relevances, results);
  return true;
}

void BaseSearchProvider::SortResults(bool is_keyword,
                                     const base::ListValue* relevances,
                                     Results* results) {
}

void BaseSearchProvider::DeleteMatchFromMatches(
    const AutocompleteMatch& match) {
  for (ACMatches::iterator i(matches_.begin()); i != matches_.end(); ++i) {
    // Find the desired match to delete by checking the type and contents.
    // We can't check the destination URL, because the autocomplete controller
    // may have reformulated that. Not that while checking for matching
    // contents works for personalized suggestions, if more match types gain
    // deletion support, this algorithm may need to be re-examined.
    if (i->contents == match.contents && i->type == match.type) {
      matches_.erase(i);
      break;
    }
  }
}

void BaseSearchProvider::OnDeletionComplete(
    bool success, SuggestionDeletionHandler* handler) {
  RecordDeletionResult(success);
  SuggestionDeletionHandlers::iterator it = std::find(
      deletion_handlers_.begin(), deletion_handlers_.end(), handler);
  DCHECK(it != deletion_handlers_.end());
  deletion_handlers_.erase(it);
}

/* [<][>][^][v][top][bottom][index][help] */