dom/file/AsyncHelper.h

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this file,
   5  * You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #ifndef mozilla_dom_file_asynchelper_h__
   8 #define mozilla_dom_file_asynchelper_h__
   9
  10 #include "FileCommon.h"
  11
  12 #include "nsIRequest.h"
  13 #include "nsIRunnable.h"
  14
  15 class nsIRequestObserver;
  16
  17 BEGIN_FILE_NAMESPACE
  18
  19 /**
  20  * Must be subclassed. The subclass must implement DoStreamWork.
  21  * Async operations that are not supported in necko (truncate, flush, etc.)
  22  * should use this helper. Call AsyncWork to invoke the operation.
  23  */
  24 class AsyncHelper : public nsIRunnable,
  25                     public nsIRequest
  26 {
  27 public:
  28   NS_DECL_ISUPPORTS
  29   NS_DECL_NSIRUNNABLE
  30   NS_DECL_NSIREQUEST
  31
  32   nsresult
  33   AsyncWork(nsIRequestObserver* aObserver, nsISupports* aCtxt);
  34
  35 protected:
  36   AsyncHelper(nsISupports* aStream)
  37   : mStream(aStream),
  38     mStatus(NS_OK)
  39   { }
  40
  41   virtual ~AsyncHelper()
  42   { }
  43
  44   virtual nsresult
  45   DoStreamWork(nsISupports* aStream) = 0;
  46
  47 private:
  48   nsCOMPtr<nsISupports> mStream;
  49   nsCOMPtr<nsIRequestObserver> mObserver;
  50
  51   nsresult mStatus;
  52 };
  53
  54 END_FILE_NAMESPACE
  55
  56 #endif // mozilla_dom_file_asynchelper_h__