1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
2 /* vim: set ts=8 sts=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
5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
6 
7 #ifndef nsICancelableRunnable_h__
8 #define nsICancelableRunnable_h__
9 
10 #include "nsISupports.h"
11 
12 #define NS_ICANCELABLERUNNABLE_IID                   \
13   {                                                  \
14     0xde93dc4c, 0x5eea, 0x4eb7, {                    \
15       0xb6, 0xd1, 0xdb, 0xf1, 0xe0, 0xce, 0xf6, 0x5c \
16     }                                                \
17   }
18 
19 class nsICancelableRunnable : public nsISupports {
20  public:
21   NS_DECLARE_STATIC_IID_ACCESSOR(NS_ICANCELABLERUNNABLE_IID)
22 
23   /*
24    * Cancels a pending task, so that calling run() on the task is a no-op.
25    * Calling cancel after the task execution has begun will be a no-op.
26    * Calling this method twice is considered an error.
27    *
28    * @throws NS_ERROR_UNEXPECTED
29    *   Indicates that the runnable has already been canceled.
30    */
31   virtual nsresult Cancel() = 0;
32 
33  protected:
34   nsICancelableRunnable() = default;
35   virtual ~nsICancelableRunnable() = default;
36 };
37 
38 NS_DEFINE_STATIC_IID_ACCESSOR(nsICancelableRunnable, NS_ICANCELABLERUNNABLE_IID)
39 
40 #endif  // nsICancelableRunnable_h__
41