Cleanup FileSystemOperation for preparing for adding FSO-factory method

webkit/fileapi/file_system_operation_interface.h

 // Copyright (c) 2011 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_OPERATION_INTERFACE_H_
 #define WEBKIT_FILEAPI_FILE_SYSTEM_OPERATION_INTERFACE_H_
 
 #include "base/process.h"
 
 namespace base {
 class Time;
 }  // namespace base
 
 namespace net {
 class URLRequest;
 class URLRequestContext;
 }  // namespace net
 
 class GURL;
 
 namespace fileapi {
 
+class FileSystemCallbackDispatcher;
+
 // The interface class for FileSystemOperation implementations.
 //
 // This interface defines file system operations required to implement
 // "File API: Directories and System"
 // http://www.w3.org/TR/file-system-api/
 //
 // DESIGN NOTES
 //
 // This class is designed to
 //
 // 1) Serve one-time file system operation per instance.  Only one
 // method(CreateFile, CreateDirectory, Copy, Move, DirectoryExists,
 // GetMetadata, ReadDirectory and Remove) may be called during the
 // lifetime of this object and it should be called no more than once.
 //
 // 2) Be self-destructed, or get deleted via base::Owned() after the
 // operation finishes and completion callback is called.
 //
 // 3) Deliver the results of operations to the client via
 // FileSystemCallbackDispatcher.
 // TODO(kinuko): Change the functions to take callbacks instead.
 //
 class FileSystemOperationInterface {
  public:
   virtual ~FileSystemOperationInterface() {}
 
-  // Opens a file system at |origin_url| of the |type|. Creates a new file
-  // system if |create| is true.
-  virtual void OpenFileSystem(const GURL& origin_url,
-                              fileapi::FileSystemType type,
-                              bool create) = 0;
-
   // Creates a file at |path|. If |exclusive| is true, an error is raised
   // in case a file is already present at the URL.
   virtual void CreateFile(const GURL& path,
                           bool exclusive) = 0;
 
   // Creates a directory at |path|. If |exclusive| is true, an error is
   // raised in case a directory is already present at the URL. If
   // |recursive| is true, create parent directories as needed just like
   // mkdir -p does.
   virtual void CreateDirectory(const GURL& path,
@@ skipping 33 matching lines @@
   virtual void Write(const net::URLRequestContext* url_request_context,
                      const GURL& path,
                      const GURL& blob_url,
                      int64 offset) = 0;
 
   // Truncates a file at |path| to |length|. If |length| is larger than
   // the original file size, the file will be extended, and the extended
   // part is filled with null bytes.
   virtual void Truncate(const GURL& path, int64 length) = 0;
 
+  // Tries to cancel the current operation [we support cancelling write or
+  // truncate only]. Reports failure for the current operation, then reports
+  // success for the cancel operation itself via the |cancel_dispatcher|.
+  //
+  // E.g. a typical cancel implementation would look like:
+  //
+  //   virtual void SomeOperationImpl::Cancel(
+  //       scoped_ptr<FileSystemCallbackDispatcher> cancel_dispatcher) {
+  //     // Abort the current inflight operation first.
+  //     ...
+  //
+  //     // Dispatch ABORT error for the current operation by calling
+  //     // DidFail() callback of the dispatcher attached to this operation.
+  //     // (dispatcher_ in this example)
+  //     dispatcher_->DidFail(base::PLATFORM_FILE_ERROR_ABORT);
+  //
+  //     // Dispatch 'success' for the cancel (or dispatch appropriate
+  //     // error code with DidFail() if the cancel has somehow failed).
+  //     cancel_dispatcher->DidSucceed();
+  //   }
+  //
+  virtual void Cancel(
+      scoped_ptr<FileSystemCallbackDispatcher> cancel_dispatcher) = 0;
+
   // Modifies timestamps of a file or directory at |path| with
   // |last_access_time| and |last_modified_time|. The function DOES NOT
   // create a file unlike 'touch' command on Linux.
   //
   // This function is used only by Pepper as of writing.
   virtual void TouchFile(const GURL& path,
                          const base::Time& last_access_time,
                          const base::Time& last_modified_time) = 0;
 
   // Opens a file at |path| with |file_flags|, where flags are OR'ed
   // values of base::PlatformFileFlags.
   //
   // |peer_handle| is the process handle of a pepper plugin process, which
   // is necessary for underlying IPC calls with Pepper plugins.
   //
   // This function is used only by Pepper as of writing.
   virtual void OpenFile(
       const GURL& path,
       int file_flags,
       base::ProcessHandle peer_handle) = 0;
 };
 
 }  // namespace fileapi
 
 #endif  // WEBKIT_FILEAPI_FILE_SYSTEM_OPERATION_INTERFACE_H_