Add FileSystemMountPointProvider::CreateFileReader() which returns appropriate Reader instance

webkit/chromeos/fileapi/cros_mount_point_provider.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/chromeos/fileapi/cros_mount_point_provider.h"
 
 #include "base/chromeos/chromeos_version.h"
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/message_loop.h"
 #include "base/message_loop_proxy.h"
 #include "base/stringprintf.h"
 #include "base/synchronization/lock.h"
 #include "base/utf_string_conversions.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebSecurityOrigin.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/platform/WebCString.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/platform/WebFileSystem.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/platform/WebString.h"
 #include "webkit/chromeos/fileapi/file_access_permissions.h"
 #include "webkit/chromeos/fileapi/remote_file_system_operation.h"
+#include "webkit/fileapi/file_system_file_reader.h"
 #include "webkit/fileapi/file_system_operation.h"
 #include "webkit/fileapi/file_system_util.h"
 #include "webkit/fileapi/native_file_util.h"
 #include "webkit/glue/webkit_glue.h"
 
 namespace {
 
 const char kChromeUIScheme[] = "chrome";
 
 // Returns the home directory path, or an empty string if the home directory
@@ skipping 214 matching lines @@
     const FilePath& virtual_path,
     base::MessageLoopProxy* file_proxy,
     fileapi::FileSystemContext* context) const {
   const MountPoint* mount_point = GetMountPoint(virtual_path);
   if (mount_point && mount_point->location == REMOTE)
     return new chromeos::RemoteFileSystemOperation(mount_point->remote_proxy);
 
   return new fileapi::FileSystemOperation(file_proxy, context);
 }
 
+webkit_blob::FileReader* CrosMountPointProvider::CreateFileReader(
+    const GURL& url,
+    int64 offset,
+    base::MessageLoopProxy* file_proxy,
+    fileapi::FileSystemContext* context) const {
+  // For now we return a generic Reader implementation which utilizes
+  // CreateSnapshotFile internally (i.e. will download everything first).
+  // TODO(satorux,zel): implement more efficient reader for remote cases.
+  return new fileapi::FileSystemFileReader(file_proxy, context, url, offset);
+}
+
 bool CrosMountPointProvider::GetVirtualPath(const FilePath& filesystem_path,
                                            FilePath* virtual_path) {
   for (MountPointMap::const_iterator iter = mount_point_map_.begin();
        iter != mount_point_map_.end();
        ++iter) {
     FilePath mount_prefix = iter->second.local_root_path.Append(iter->first);
     *virtual_path = FilePath(iter->first);
     if (mount_prefix == filesystem_path) {
       return true;
     } else if (mount_prefix.AppendRelativePath(filesystem_path, virtual_path)) {
       return true;
     }
   }
   return false;
 }
 
 }  // namespace chromeos