fileapi: Add modification time check for FileSystemFileStreamReader

webkit/fileapi/file_system_mount_point_provider.h

 // 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.
 
 #ifndef WEBKIT_FILEAPI_FILE_SYSTEM_MOUNT_POINT_PROVIDER_H_
 #define WEBKIT_FILEAPI_FILE_SYSTEM_MOUNT_POINT_PROVIDER_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 69 matching lines @@
   // and |virtual_path|. On failure to create a file system operation, set
   // |error_code| correspondingly.
   // This method is usually dispatched by
   // FileSystemContext::CreateFileSystemOperation.
   virtual FileSystemOperation* CreateFileSystemOperation(
       const FileSystemURL& url,
       FileSystemContext* context,
       base::PlatformFileError* error_code) const = 0;
 
   // Creates a new file stream reader for a given filesystem URL |url| with an
-  // offset |offset|.
+  // offset |offset|. |expected_modification_time| specifies the expected last
+  // modification if the value is non-null, the reader will check the underlying
+  // file's actual modification time to see if the file has been modified, and
+  // if it does any succeeding read operations should fail with
+  // ERR_UPLOAD_FILE_CHANGED error.
   // The returned object must be owned and managed by the caller.
   // This method itself does *not* check if the given path exists and is a
   // regular file.
   virtual webkit_blob::FileStreamReader* CreateFileStreamReader(
     const FileSystemURL& url,
     int64 offset,
+    const base::Time& expected_modification_time,
     FileSystemContext* context) const = 0;
 
   // Creates a new file stream writer for a given filesystem URL |url| with an
   // offset |offset|.
   // The returned object must be owned and managed by the caller.
   // This method itself does *not* check if the given path exists and is a
   // regular file.
   virtual FileStreamWriter* CreateFileStreamWriter(
       const FileSystemURL& url,
       int64 offset,
@@ skipping 44 matching lines @@
   virtual void RemoveMountPoint(const FilePath& mount_point) = 0;
   // Gets virtual path by known filesystem path. Returns false when filesystem
   // path is not exposed by this provider.
   virtual bool GetVirtualPath(const FilePath& file_system_path,
                               FilePath* virtual_path) = 0;
 };
 
 }  // namespace fileapi
 
 #endif  // WEBKIT_FILEAPI_FILE_SYSTEM_MOUNT_POINT_PROVIDER_H_