Fetch snippets from ChromeReader and show them on the NTP

components/ntp_snippets/ntp_snippets_service.cc

 // 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.
 
 #include "components/ntp_snippets/ntp_snippets_service.h"
 
+#include "base/files/file_path.h"
+#include "base/files/file_util.h"
 #include "base/json/json_string_value_serializer.h"
+#include "base/location.h"
+#include "base/path_service.h"
+#include "base/task_runner_util.h"
 #include "base/values.h"
 
 namespace ntp_snippets {
 
+bool ReadFileToString(const base::FilePath& path, std::string* data) {
+  DCHECK(data);
+  bool success = base::ReadFileToString(path, data);
+  DLOG_IF(ERROR, !success) << "Error reading file " << path.LossyDisplayName();
+  return success;
+}
+
 NTPSnippetsService::NTPSnippetsService(
-    const std::string& application_language_code)
-    : loaded_(false), application_language_code_(application_language_code) {}
+    scoped_refptr<base::SequencedTaskRunner> file_task_runner,
+    const std::string& application_language_code,
+    scoped_ptr<NTPSnippetsFetcher> snippets_fetcher)
+    : loaded_(false),
+      file_task_runner_(file_task_runner),
+      application_language_code_(application_language_code),
+      snippets_fetcher_(std::move(snippets_fetcher)),
+      weak_ptr_factory_(this) {
+  snippets_fetcher_callback_ = snippets_fetcher_->AddCallback(
+      base::Bind(&NTPSnippetsService::OnSnippetsDownloaded,
+                 weak_ptr_factory_.GetWeakPtr()));
+}
 
 NTPSnippetsService::~NTPSnippetsService() {}
 
 void NTPSnippetsService::Shutdown() {
   FOR_EACH_OBSERVER(NTPSnippetsServiceObserver, observers_,
                     NTPSnippetsServiceShutdown(this));
   loaded_ = false;
 }
 
+void NTPSnippetsService::FetchSnippets(bool overwrite) {
+  snippets_fetcher_->FetchSnippets(overwrite);
+}
+
 void NTPSnippetsService::AddObserver(NTPSnippetsServiceObserver* observer) {
   observers_.AddObserver(observer);
   if (loaded_)
     observer->NTPSnippetsServiceLoaded(this);
 }
 
 void NTPSnippetsService::RemoveObserver(NTPSnippetsServiceObserver* observer) {
   observers_.RemoveObserver(observer);
 }
 
+void NTPSnippetsService::OnFileReadDone(const std::string* json, bool success) {
+  if (!success)
+    return;
+
+  DCHECK(json);
+  LoadFromJSONString(*json);
+}
+
 bool NTPSnippetsService::LoadFromJSONString(const std::string& str) {
   JSONStringValueDeserializer deserializer(str);
   int error_code;
   std::string error_message;
 
   scoped_ptr<base::Value> deserialized =
       deserializer.Deserialize(&error_code, &error_message);
   if (!deserialized)
     return false;
 
   const base::DictionaryValue* top_dict = NULL;
   if (!deserialized->GetAsDictionary(&top_dict))
     return false;
 
   const base::ListValue* list = NULL;
   if (!top_dict->GetList("recos", &list))
     return false;
 
   for (base::Value* const value : *list) {
     const base::DictionaryValue* dict = NULL;
     if (!value->GetAsDictionary(&dict))
       return false;
 
     const base::DictionaryValue* content = NULL;
     if (!dict->GetDictionary("contentInfo", &content))
       return false;
-    std::unique_ptr<NTPSnippet> snippet =
+    scoped_ptr<NTPSnippet> snippet =
         NTPSnippet::NTPSnippetFromDictionary(*content);
     if (!snippet)
       return false;
     snippets_.push_back(std::move(snippet));
   }
   loaded_ = true;
+
   FOR_EACH_OBSERVER(NTPSnippetsServiceObserver, observers_,
                     NTPSnippetsServiceLoaded(this));
   return true;
 }
 
+void NTPSnippetsService::OnSnippetsDownloaded(
+    const base::FilePath& download_path) {
+  std::string* downloaded_data = new std::string;
+  base::PostTaskAndReplyWithResult(
+      file_task_runner_.get(), FROM_HERE,
+      base::Bind(&ReadFileToString, download_path, downloaded_data),
+      base::Bind(&NTPSnippetsService::OnFileReadDone,
+                 weak_ptr_factory_.GetWeakPtr(), base::Owned(downloaded_data)));
+}
+
 }  // namespace ntp_snippets