Make OperationID usable for error handling.

webkit/browser/fileapi/file_system_operation_runner.h

 // Copyright 2013 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_BROWSER_FILEAPI_FILE_SYSTEM_OPERATION_RUNNER_H_
 #define WEBKIT_BROWSER_FILEAPI_FILE_SYSTEM_OPERATION_RUNNER_H_
 
 #include <map>
 
 #include "base/basictypes.h"
 #include "base/id_map.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
 #include "webkit/browser/fileapi/file_system_operation.h"
 #include "webkit/browser/fileapi/file_system_url.h"
 #include "webkit/browser/webkit_storage_browser_export.h"
 
 namespace net {
 class URLRequestContext;
 }
 
 namespace fileapi {
 
 class FileSystemURL;
 class FileSystemContext;
 
 // A central interface for running FileSystem API operations.
 // All operation methods take callback and returns OperationID, which is
 // an integer value which can be used for cancelling an operation.
-// All operation methods return kErrorOperationID if running (posting) an
+// All operation methods return valid OperationID even if running (posting) an
 // operation fails, in addition to dispatching the callback with an error
 // code (therefore in most cases the caller does not need to check the
 // returned operation ID).
 class WEBKIT_STORAGE_BROWSER_EXPORT FileSystemOperationRunner
     : public base::SupportsWeakPtr<FileSystemOperationRunner> {
  public:
   typedef FileSystemOperation::GetMetadataCallback GetMetadataCallback;
   typedef FileSystemOperation::ReadDirectoryCallback ReadDirectoryCallback;
   typedef FileSystemOperation::SnapshotFileCallback SnapshotFileCallback;
   typedef FileSystemOperation::StatusCallback StatusCallback;
   typedef FileSystemOperation::WriteCallback WriteCallback;
   typedef FileSystemOperation::OpenFileCallback OpenFileCallback;
 
   typedef int OperationID;
 
-  static const OperationID kErrorOperationID;
-
   virtual ~FileSystemOperationRunner();
 
   // Cancels all inflight operations.
   void Shutdown();
 
   // Creates a file at |url|. If |exclusive| is true, an error is raised
   // in case a file is already present at the URL.
   OperationID CreateFile(const FileSystemURL& url,
                          bool exclusive,
                          const StatusCallback& callback);
@@ skipping 215 matching lines @@
   // we can notify observers when we're done.
   typedef std::map<OperationID, FileSystemURLSet> OperationToURLSet;
   OperationToURLSet write_target_urls_;
 
   DISALLOW_COPY_AND_ASSIGN(FileSystemOperationRunner);
 };
 
 }  // namespace fileapi
 
 #endif  // WEBKIT_BROWSER_FILEAPI_FILE_SYSTEM_OPERATION_RUNNER_H_