FetchMore functionality backend

components/ntp_snippets/remote/ntp_snippets_service.h

Index: components/ntp_snippets/remote/ntp_snippets_service.h
diff --git a/components/ntp_snippets/remote/ntp_snippets_service.h b/components/ntp_snippets/remote/ntp_snippets_service.h
index 6af55c661113107e0ec9025f942c84daa168a137..82f005bda0055258ba3774d7020e883c1ca17b53 100644
--- a/components/ntp_snippets/remote/ntp_snippets_service.h
+++ b/components/ntp_snippets/remote/ntp_snippets_service.h
@@ -117,6 +117,8 @@ class NTPSnippetsService final : public ContentSuggestionsProvider,
   void DismissSuggestion(const ContentSuggestion::ID& suggestion_id) override;
   void FetchSuggestionImage(const ContentSuggestion::ID& suggestion_id,
                             const ImageFetchedCallback& callback) override;
+  void FetchMore(const Category& category,
+                 const FetchedMoreCallback& callback) override;
   void ClearHistory(
       base::Time begin,
       base::Time end,
@@ -209,6 +211,8 @@ class NTPSnippetsService final : public ContentSuggestionsProvider,
 
   // Callback for the NTPSnippetsFetcher.
   void OnFetchFinished(
+      bool fetched_more,
+      const FetchedMoreCallback& fetched_more_callback,
       NTPSnippetsFetcher::OptionalFetchedCategories fetched_categories);
 
   // Moves all snippets from |to_archive| into the archive of the |category|.
@@ -216,8 +220,15 @@ class NTPSnippetsService final : public ContentSuggestionsProvider,
   // short.
   void ArchiveSnippets(Category category, NTPSnippet::PtrVector* to_archive);
 
-  // Replace old snippets in |category| by newly available snippets.
-  void ReplaceSnippets(Category category, NTPSnippet::PtrVector new_snippets);
+  // Add newly available snippets in |category| to the provided content.

[vitaliii, 2016/11/01 23:29:58]

s/Add/Adds

[fhorschig, 2016/11/02 05:05:28]

Done in CL 2446163005.

+  // If |replace_snippets| is set, archive existing snippets.

[vitaliii, 2016/11/01 23:29:57]

nit: remove "is set"

[fhorschig, 2016/11/02 05:05:28]

Done in CL 2446163005.

+  void IncludeSnippets(const Category& category,
+                       NTPSnippet::PtrVector new_snippets,
+                       bool replace_snippets);
+
+  void SaveSnippets(const Category& category,
+                    NTPSnippet::PtrVector new_snippets,
+                    bool replace_snippets);
 
   // Removes expired dismissed snippets from the service and the database.
   void ClearExpiredDismissedSnippets();
@@ -272,7 +283,13 @@ class NTPSnippetsService final : public ContentSuggestionsProvider,
   void EnterStateError();
 
   // Converts the cached snippets in the given |category| to content suggestions
-  // and notifies the observer.
+  // and calls a passed callback. If no callbakc is given it notifies the

[vitaliii, 2016/11/01 23:29:58]

s/callbakc/callbaCK
s/it/,

[fhorschig, 2016/11/02 05:05:28]

Done in CL 2446163005.

+  // observer.
+  void NotifyNewSuggestionsOrInvokeCallback(
+    Category category,
+    FetchedMoreCallback fetched_more_callback);
+  // Triggers notification of observer by calling
+  // |NotifyNewSuggestionsOrInvokeCallback| with a null callback.
   void NotifyNewSuggestions(Category category);
 
   // Updates the internal status for |category| to |category_status_| and
@@ -284,6 +301,27 @@ class NTPSnippetsService final : public ContentSuggestionsProvider,
   void RestoreCategoriesFromPrefs();
   void StoreCategoriesToPrefs();
 
+  // Implementation for |FetchSnippets| and |FetchMore| that calls the snippet
+  // fetcher and replaces or adds the fetched snippets depending on the passed
+  // |strategy|.
+  void FetchSnippetsFromHostsImpl(
+      const std::set<std::string>& hosts,
+      bool interactive_request,
+      bool fetch_more,
+      base::Optional<Category> exclusive_category,
+      const FetchedMoreCallback& fetched_more_callback);
+  void MarkEmptyCategoriesAsLoading(NTPSnippetsFetcher::Params* params);
+  void AssignExpiryDates(NTPSnippet::PtrVector* snippets);
+  void AddIncompleteSnippets(NTPSnippet::PtrVector* snippets);
+  void FinishFetch(
+    NTPSnippetsFetcher::OptionalFetchedCategories fetched_categories,
+    bool replace_existing_snippets);
+  // Returns a set of snippet ids that are should not be fetched in subsequent

[vitaliii, 2016/11/01 23:29:58]

grammar: remove "are"

[fhorschig, 2016/11/02 05:05:28]

Done in CL 2446163005.

+  // requests. These IDs akways include dismissed snippets.

[vitaliii, 2016/11/01 23:29:57]

IDs is inconsistent with the previous line.
s/akways/aLways

[fhorschig, 2016/11/02 05:05:28]

Done in CL 2446163005.

+  // For |fetch more| requests, all known snippets are returned.
+  std::set<std::string> CollectIdsToExclude(bool fetch_more);
+  void MarkEmptyCategoriesAsLoading();
+
   State state_;
 
   PrefService* pref_service_;
@@ -324,7 +362,9 @@ class NTPSnippetsService final : public ContentSuggestionsProvider,
     ~CategoryContent();
     CategoryContent& operator=(CategoryContent&&);
   };
-  std::map<Category, CategoryContent, Category::CompareByID> categories_;
+  using CategoryContentMap =
+      std::map<Category, CategoryContent, Category::CompareByID>;
+  CategoryContentMap categories_;
 
   // The ISO 639-1 code of the language used by the application.
   const std::string application_language_code_;