Refactor FileSystemMountPointProvider::CreateFileStream{Reader,Writer}

webkit/fileapi/file_system_context.cc

 // Copyright (c) 2012 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 "webkit/fileapi/file_system_context.h"
 
 #include "base/bind.h"
 #include "base/stl_util.h"
 #include "base/single_thread_task_runner.h"
 #include "googleurl/src/gurl.h"
+#include "webkit/blob/file_stream_reader.h"
 #include "webkit/fileapi/copy_or_move_file_validator.h"
 #include "webkit/fileapi/external_mount_points.h"
+#include "webkit/fileapi/file_stream_writer.h"
 #include "webkit/fileapi/file_system_file_util.h"
 #include "webkit/fileapi/file_system_operation.h"
 #include "webkit/fileapi/file_system_options.h"
 #include "webkit/fileapi/file_system_quota_client.h"
 #include "webkit/fileapi/file_system_task_runners.h"
 #include "webkit/fileapi/file_system_url.h"
 #include "webkit/fileapi/file_system_util.h"
 #include "webkit/fileapi/isolated_context.h"
 #include "webkit/fileapi/isolated_mount_point_provider.h"
 #include "webkit/fileapi/mount_points.h"
@@ skipping 261 matching lines @@
 
   base::PlatformFileError fs_error = base::PLATFORM_FILE_OK;
   FileSystemOperation* operation =
       mount_point_provider->CreateFileSystemOperation(url, this, &fs_error);
 
   if (error_code)
     *error_code = fs_error;
   return operation;
 }
 
-webkit_blob::FileStreamReader* FileSystemContext::CreateFileStreamReader(
+scoped_ptr<webkit_blob::FileStreamReader>
+FileSystemContext::CreateFileStreamReader(
     const FileSystemURL& url,
     int64 offset,
     const base::Time& expected_modification_time) {
   if (!url.is_valid())
-    return NULL;
+    return scoped_ptr<webkit_blob::FileStreamReader>();
   FileSystemMountPointProvider* mount_point_provider =
       GetMountPointProvider(url.type());
   if (!mount_point_provider)
-    return NULL;
+    return scoped_ptr<webkit_blob::FileStreamReader>();
   return mount_point_provider->CreateFileStreamReader(
       url, offset, expected_modification_time, this);
 }
 
-FileStreamWriter* FileSystemContext::CreateFileStreamWriter(
+scoped_ptr<FileStreamWriter> FileSystemContext::CreateFileStreamWriter(
     const FileSystemURL& url,
     int64 offset) {
   if (!url.is_valid())
-    return NULL;
+    return scoped_ptr<FileStreamWriter>();
   FileSystemMountPointProvider* mount_point_provider =
       GetMountPointProvider(url.type());
   if (!mount_point_provider)
-    return NULL;
+    return scoped_ptr<FileStreamWriter>();
   return mount_point_provider->CreateFileStreamWriter(url, offset, this);
 }
 
 void FileSystemContext::RegisterMountPointProvider(
     FileSystemType type,
     FileSystemMountPointProvider* provider) {
   DCHECK(provider);
   DCHECK(provider_map_.find(type) == provider_map_.end());
   provider_map_[type] = provider;
 }
@@ skipping 72 matching lines @@
 FileSystemFileUtil* FileSystemContext::GetFileUtil(
     FileSystemType type) const {
   FileSystemMountPointProvider* mount_point_provider =
       GetMountPointProvider(type);
   if (!mount_point_provider)
     return NULL;
   return mount_point_provider->GetFileUtil(type);
 }
 
 }  // namespace fileapi