components/omnibox/browser/most_visited_sites_provider.h

// Copyright (c) 2020 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.

#ifndef COMPONENTS_OMNIBOX_BROWSER_MOST_VISITED_SITES_PROVIDER_H_
#define COMPONENTS_OMNIBOX_BROWSER_MOST_VISITED_SITES_PROVIDER_H_

#include <memory>
#include <string>

#include "base/compiler_specific.h"
#include "base/memory/weak_ptr.h"
#include "components/omnibox/browser/autocomplete_input.h"
#include "components/omnibox/browser/autocomplete_provider.h"
#include "components/omnibox/browser/autocomplete_provider_client.h"
#include "components/omnibox/browser/autocomplete_provider_listener.h"
#include "third_party/metrics_proto/omnibox_event.pb.h"

// Autocomplete provider serving Most Visited Sites in zero-prefix context.
// Serves most frequently visited URLs in a form of either individual- or
// aggregate suggestions.
class MostVisitedSitesProvider : public AutocompleteProvider {
 public:
  MostVisitedSitesProvider(AutocompleteProviderClient* client,
                           AutocompleteProviderListener* listener);

  void Start(const AutocompleteInput& input, bool minimal_changes) override;
  void Stop(bool clear_cached_results, bool due_to_user_inactivity) override;

 private:
  FRIEND_TEST_ALL_PREFIXES(MostVisitedSitesProviderTest,
                           AllowMostVisitedSitesSuggestions);

  ~MostVisitedSitesProvider() override;

  // Constructs an AutocompleteMatch from supplied details.
  AutocompleteMatch BuildMatch(const std::u16string& description,
                               const GURL& url,
                               int relevance,
                               AutocompleteMatchType::Type type);

  // When the TopSites service serves the most visited URLs, this function
  // converts those urls to AutocompleteMatches and adds them to |matches_|.
  void OnMostVisitedUrlsAvailable(const history::MostVisitedURLList& urls);

  // Whether zero suggest suggestions are allowed in the given context.
  // Invoked early, confirms all the external conditions for ZeroSuggest are
  // met.
  bool AllowMostVisitedSitesSuggestions(const AutocompleteInput& input) const;

  AutocompleteProviderClient* const client_;
  AutocompleteProviderListener* const listener_;
  // Note: used to cancel requests - not a general purpose WeakPtr factory.
  base::WeakPtrFactory<MostVisitedSitesProvider> request_weak_ptr_factory_{
      this};
};

#endif  // COMPONENTS_OMNIBOX_BROWSER_MOST_VISITED_SITES_PROVIDER_H_