[fsp] Add support for aborting running operations.

chrome/browser/chromeos/file_system_provider/fileapi/file_stream_writer.h

 // Copyright 2014 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 CHROME_BROWSER_CHROMEOS_FILE_SYSTEM_PROVIDER_FILEAPI_FILE_STREAM_WRITER_H_
 #define CHROME_BROWSER_CHROMEOS_FILE_SYSTEM_PROVIDER_FILEAPI_FILE_STREAM_WRITER_H_
 
 #include "base/basictypes.h"
 #include "base/files/file.h"
 #include "base/files/file_path.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/weak_ptr.h"
 #include "webkit/browser/fileapi/file_stream_writer.h"
 #include "webkit/browser/fileapi/file_system_url.h"
 
 namespace chromeos {
 namespace file_system_provider {
 
 class ProvidedFileSystemInterface;
 
 // Implements a streamed file writer. It is lazily initialized by the first call
 // to Write().
 class FileStreamWriter : public fileapi::FileStreamWriter {
  public:
-  typedef base::Callback<
-      void(base::WeakPtr<ProvidedFileSystemInterface> file_system,
-           const base::FilePath& file_path,
-           int file_handle,
-           base::File::Error result)> OpenFileCompletedCallback;
-
   FileStreamWriter(const fileapi::FileSystemURL& url, int64 initial_offset);
 
   virtual ~FileStreamWriter();
 
   // fileapi::FileStreamWriter overrides.
   virtual int Write(net::IOBuffer* buf,
                     int buf_len,
                     const net::CompletionCallback& callback) OVERRIDE;
   virtual int Cancel(const net::CompletionCallback& callback) OVERRIDE;
   virtual int Flush(const net::CompletionCallback& callback) OVERRIDE;
 
  private:
+  // Helper class for executing operations on the provided file system. All
+  // of its methods must be called on UI thread. Callbacks are called on IO
+  // thread.
+  class OperationRunner;
+
   // State of the file stream writer.
   enum State { NOT_INITIALIZED, INITIALIZING, INITIALIZED, FAILED };
 
+  // Called when OperationRunner::WriteOnUIThread is completed.
   void OnWriteFileCompleted(int buffer_length,
                             const net::CompletionCallback& callback,
                             base::File::Error result);
 
-  // Called when Write() operation is completed with either a success of an
+  // Called when Write() operation is completed with either a success or an
   // error.
   void OnWriteCompleted(net::CompletionCallback callback, int result);
 
+  // Called when Abort() operation is completed with either a success or an
+  // error.
+  void OnAbortCompleted(const net::CompletionCallback& callback,
+                        base::File::Error result);
+
   // Initializes the writer by opening the file. When completed with success,
   // runs the |pending_closure|. Otherwise, calls the |error_callback|.
   void Initialize(const base::Closure& pending_closure,
                   const net::CompletionCallback& error_callback);
 
   // Called when opening a file is completed with either a success or an error.
   void OnOpenFileCompleted(
       const base::Closure& pending_closure,
       const net::CompletionCallback& error_callback,
-      base::WeakPtr<ProvidedFileSystemInterface> file_system,
-      const base::FilePath& file_path,
-      int file_handle,
       base::File::Error result);
 
   // Same as Write(), but called after initializing is completed.
   void WriteAfterInitialized(scoped_refptr<net::IOBuffer> buffer,
                              int buffer_length,
                              const net::CompletionCallback& callback);
 
   fileapi::FileSystemURL url_;
   int64 current_offset_;
+  scoped_refptr<OperationRunner> runner_;
   State state_;
 
-  // Set during initialization (in case of a success).
-  base::WeakPtr<ProvidedFileSystemInterface> file_system_;
-  base::FilePath file_path_;
-  int file_handle_;
-
   base::WeakPtrFactory<FileStreamWriter> weak_ptr_factory_;
   DISALLOW_COPY_AND_ASSIGN(FileStreamWriter);
 };
 
 }  // namespace file_system_provider
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_FILE_SYSTEM_PROVIDER_FILEAPI_FILE_STREAM_WRITER_H_