[NTPSnippets] Show all downloads on the NTP (3/3): Downloads provider.

components/ntp_snippets/downloads/download_suggestions_provider.h

+// Copyright 2016 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_NTP_SNIPPETS_DOWNLOADS_DOWNLOAD_SUGGESTIONS_PROVIDER_H_
+#define COMPONENTS_NTP_SNIPPETS_DOWNLOADS_DOWNLOAD_SUGGESTIONS_PROVIDER_H_
+
+#include <set>
+#include <string>
+#include <vector>
+
+#include "base/callback_forward.h"
+#include "base/memory/ptr_util.h"
+#include "base/memory/weak_ptr.h"
+#include "base/time/time.h"
+#include "chrome/browser/download/all_download_item_notifier.h"
+#include "components/ntp_snippets/category.h"
+#include "components/ntp_snippets/category_factory.h"
+#include "components/ntp_snippets/category_status.h"
+#include "components/ntp_snippets/content_suggestion.h"
+#include "components/ntp_snippets/content_suggestions_provider.h"
+#include "components/ntp_snippets/offline_pages/offline_page_proxy.h"
+
+class PrefRegistrySimple;
+class PrefService;
+
+namespace gfx {
+class Image;
+}
+
+namespace ntp_snippets {
+
+// Provides download content suggestions from the offline pages model (obtaining
+// the data through OfflinePageProxy) and the download manager (obtaining the
+// data through AllDownloadItemNotifier). Offline pages related downloads are
+// referred to as offline page downloads, while other downloads (e.g. images,
+// music, books) are referred to as asset downloads.
+class DownloadSuggestionsProvider : public ContentSuggestionsProvider,
+                                    public OfflinePageProxy::Observer,
+                                    public AllDownloadItemNotifier::Observer {
+ public:
+  DownloadSuggestionsProvider(
+      ContentSuggestionsProvider::Observer* observer,
+      CategoryFactory* category_factory,
+      const scoped_refptr<OfflinePageProxy>& offline_page_proxy,
+      content::DownloadManager* download_manager,
+      PrefService* pref_service,
+      bool download_manager_ui_enabled);
+  ~DownloadSuggestionsProvider() override;
+
+  // ContentSuggestionsProvider implementation.
+  CategoryStatus GetCategoryStatus(Category category) override;
+  CategoryInfo GetCategoryInfo(Category category) override;
+  void DismissSuggestion(const std::string& suggestion_id) override;
+  void FetchSuggestionImage(const std::string& suggestion_id,
+                            const ImageFetchedCallback& callback) override;
+  void ClearHistory(
+      base::Time begin,
+      base::Time end,
+      const base::Callback<bool(const GURL& url)>& filter) override;
+  void ClearCachedSuggestions(Category category) override;
+  void GetDismissedSuggestionsForDebugging(
+      Category category,
+      const DismissedSuggestionsCallback& callback) override;
+  void ClearDismissedSuggestionsForDebugging(Category category) override;
+
+  static void RegisterProfilePrefs(PrefRegistrySimple* registry);
+
+ private:
+  // OfflinePageProxy::Observer implementation.
+  void OfflinePageModelChanged(
+      const std::vector<offline_pages::OfflinePageItem>& offline_pages)
+      override;
+  void OfflinePageDeleted(int64_t offline_id,
+                          const offline_pages::ClientId& client_id) override;
+
+  // AllDownloadItemNotifier::Observer implementation.
+  void OnDownloadCreated(content::DownloadManager* manager,
+                         content::DownloadItem* item) override;
+  void OnDownloadUpdated(content::DownloadManager* manager,
+                         content::DownloadItem* item) override;
+  void OnDownloadOpened(content::DownloadManager* manager,
+                        content::DownloadItem* item) override;
+  void OnDownloadRemoved(content::DownloadManager* manager,
+                         content::DownloadItem* item) override;
+
+  // Updates the |category_status_| of the |provided_category_| and notifies the
+  // |observer_|, if necessary.
+  void NotifyStatusChanged(CategoryStatus new_status);
+
+  // Manually requests all offline pages and after asynchronously obtaining the
+  // result caches some most recent ones and updates the suggestions through
+  // |SubmitContentSuggestions|.
+  void FetchOfflinePagesDownloadsAndSubmitSuggestions();
+
+  // Manually syncronously retrieves all asset downloads and caches them.
+  void FetchAssetsDownloads();
+
+  // Manually downloads both offline page and asset downloads, caches them and
+  // updates the suggestions through |SubmitContentSuggestions|.
+  void FetchAllDownloadsAndSubmitSuggestions();
+
+  // Takes |kMaxSuggestionsCount| cached suggestions and notifies the service
+  // about them.
+  void SubmitContentSuggestions();
+
+  // Converts an OfflinePageItem to a ContentSuggestion for the
+  // |provided_category_|.
+  ContentSuggestion ConvertOfflinePage(
+      const offline_pages::OfflinePageItem& offline_page) const;
+
+  // Converts DownloadItem to a ContentSuggestion for the |provided_category_|.
+  ContentSuggestion ConvertDownloadItem(
+      const content::DownloadItem* download_item) const;
+
+  // Fires the |OnSuggestionInvalidated| event for the suggestion corresponding
+  // to the given |id_in_category| and clears it from the dismissed IDs list, if
+  // necessary.
+  void InvalidateSuggestion(const std::string& id_in_category);
+
+  // Reads dismissed IDs related to asset downloads from Prefs.
+  std::set<std::string> ReadAssetDismissedIDsFromPrefs() const;
+
+  // Writes |dismissed_ids| into Prefs for asset downloads.
+  void StoreAssetDismissedIDsToPrefs(
+      const std::set<std::string>& dismissed_ids);
+
+  // Reads dismissed IDs related to offline page downloads from Prefs.
+  std::set<std::string> ReadOfflinePageDismissedIDsFromPrefs() const;
+
+  // Writes |dismissed_ids| into Prefs for offline page downloads.
+  void StoreOfflinePageDismissedIDsToPrefs(
+      const std::set<std::string>& dismissed_ids);
+
+  CategoryStatus category_status_;
+  const Category provided_category_;
+  scoped_refptr<OfflinePageProxy> offline_page_proxy_;
+  AllDownloadItemNotifier download_manager_notifier_;
+
+  PrefService* pref_service_;
+
+  // Cached offline page downloads. Any of them could be shown. Order is
+  // undefined.
+  std::vector<offline_pages::OfflinePageItem> cached_offline_page_downloads_;
+  // Cached asset downloads. Any of them could be shown. Order is undefined.
+  std::vector<content::DownloadItem*> cached_asset_downloads_;
+
+  // Whether the Download Manager UI is enabled, in which case the More button
+  // for the Downloads section can redirect there.
+  bool download_manager_ui_enabled_;
+
+  base::WeakPtrFactory<DownloadSuggestionsProvider> weak_ptr_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(DownloadSuggestionsProvider);
+};
+
+}  // namespace ntp_snippets
+
+#endif  // COMPONENTS_NTP_SNIPPETS_RECENT_TABS_RECENT_TAB_SUGGESTIONS_PROVIDER_H_