Fetch snippets from ChromeReader and show them on the NTP

components/ntp_snippets/ntp_snippets_service.h

 // Copyright 2015 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_NTP_SNIPPETS_SERVICE_H_
 #define COMPONENTS_NTP_SNIPPETS_NTP_SNIPPETS_SERVICE_H_
 
 #include <stddef.h>
 
 #include <string>
 #include <vector>
 
 #include "base/macros.h"
+#include "base/memory/weak_ptr.h"
 #include "base/observer_list.h"
+#include "base/sequenced_task_runner.h"
 #include "components/keyed_service/core/keyed_service.h"
 #include "components/ntp_snippets/inner_iterator.h"
 #include "components/ntp_snippets/ntp_snippet.h"
+#include "components/ntp_snippets/ntp_snippets_fetcher.h"
 
 namespace ntp_snippets {
 
 class NTPSnippetsServiceObserver;
 
 // Stores and vend fresh content data for the NTP.
-class NTPSnippetsService : public KeyedService {
+class NTPSnippetsService : public KeyedService, NTPSnippetsFetcher::Observer {
  public:
   using NTPSnippetStorage = std::vector<std::unique_ptr<NTPSnippet>>;
   using const_iterator =
       InnerIterator<NTPSnippetStorage::const_iterator, const NTPSnippet>;
 
   // |application_language_code| should be a ISO 639-1 compliant string. Aka
   // 'en' or 'en-US'. Note that this code should only specify the language, not
   // the locale, so 'en_US' (english language with US locale) and 'en-GB_US'
   // (British english person in the US) are not language code.
-  explicit NTPSnippetsService(const std::string& application_language_code);
+  NTPSnippetsService(scoped_refptr<base::SequencedTaskRunner> file_task_runner,
+                     const std::string& application_language_code,
+                     NTPSnippetsFetcher* snippets_fetcher);

[Marc Treib, 2016/02/10 10:44:43]

scoped_ptr<NTPSnippetsFetcher>
to make clear that this will take ownership. (You'll have to use std::move in
the .cc file)

[May, 2016/02/10 18:16:47]

Done.

   ~NTPSnippetsService() override;
 
+  // Fetches snippets from the server. |overwrite| is true if existing snippets
+  // should be overwritten.
+  void FetchSnippets(bool overwrite);
+
   // Inherited from KeyedService.
   void Shutdown() override;
 
   // True once the data is loaded in memory and available to loop over.
   bool is_loaded() { return loaded_; }
 
   // Observer accessors.
   void AddObserver(NTPSnippetsServiceObserver* observer);
   void RemoveObserver(NTPSnippetsServiceObserver* observer);
 
   // Expects the JSON to be a list of dictionaries with keys matching the
   // properties of a snippet (url, title, site_title, etc...). The url is the
   // only mandatory value.
   bool LoadFromJSONString(const std::string& str);

[Marc Treib, 2016/02/10 10:44:43]

I think this can be private?

[May, 2016/02/10 18:16:47]

Done.

 
   // Number of snippets available. Can only be called when is_loaded() is true.
   NTPSnippetStorage::size_type size() {
     DCHECK(loaded_);
     return snippets_.size();
   }
 
   // The snippets can be iterated upon only via a const_iterator. Recommended
   // way to iterate is as follow:
   //
   // NTPSnippetsService service; // Assume is set.
   //  for (auto& snippet : *service) {
   //    // Snippet here is a const object.
   //  }
   const_iterator begin() {
     DCHECK(loaded_);
     return const_iterator(snippets_.begin());
   }
   const_iterator end() {
     DCHECK(loaded_);
     return const_iterator(snippets_.end());
   }
 
  private:
+  void OnFileReadDone(const std::string& json);
+  void OnSnippetsDownloaded(const base::FilePath download_path);

[Marc Treib, 2016/02/10 10:44:43]

&

[May, 2016/02/10 18:16:47]

Done.

+
   // True if the suggestions are loaded.
   bool loaded_;
+
+  // The SequencedTaskRunner on which file system operations will be run.
+  scoped_refptr<base::SequencedTaskRunner> file_task_runner_;
+
   // All the suggestions.
   NTPSnippetStorage snippets_;
+
   // The ISO 639-1 code of the language used by the application.
   const std::string application_language_code_;
+
   // The observers.
   base::ObserverList<NTPSnippetsServiceObserver> observers_;
 
+  // The snippets fetcher
+  scoped_ptr<NTPSnippetsFetcher> snippets_fetcher_;
+
+  // The callback from the snippets fetcher
+  scoped_ptr<NTPSnippetsFetcher::NTPSnippetsFetcherCallbackList::Subscription>
+      snippets_fetcher_callback_;
+
+  base::WeakPtrFactory<NTPSnippetsService> weak_ptr_factory_;
+
   DISALLOW_COPY_AND_ASSIGN(NTPSnippetsService);
 };
 
 class NTPSnippetsServiceObserver {
  public:
   // Send everytime the service loads a new set of data.
   virtual void NTPSnippetsServiceLoaded(NTPSnippetsService* service) = 0;
   // Send when the service is shutting down.
   virtual void NTPSnippetsServiceShutdown(NTPSnippetsService* service) = 0;
 
  protected:
   virtual ~NTPSnippetsServiceObserver() {}
 };
 
 }  // namespace ntp_snippets
 
 #endif  // COMPONENTS_NTP_SNIPPETS_NTP_SNIPPETS_SERVICE_H_