gecko-dev/xpcom/threads/nsIDiscardableRunnable.h
Karl Tomlinson fe53cdd395 Bug 1119956 introduce DiscardableRunnable for tasks that might not run but might not implement cancellation r=asuth,sg
Classes that inherit from DiscardableRunnable are only promising that it is OK
for Run() to be skipped, rather than promising that Cancel() is effective.

Differential Revision: https://phabricator.services.mozilla.com/D98117
2020-12-02 09:36:25 +00:00

42 lines
1.3 KiB
C++

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef XPCOM_THREADS_NSIDISCARDABLERUNNABLE_H_
#define XPCOM_THREADS_NSIDISCARDABLERUNNABLE_H_
#include "nsISupports.h"
/**
* An interface implemented by nsIRunnable tasks for which nsIRunnable::Run()
* might not be called.
*/
#define NS_IDISCARDABLERUNNABLE_IID \
{ \
0xde93dc4c, 0x755c, 0x4cdc, { \
0x96, 0x76, 0x35, 0xc6, 0x48, 0x81, 0x59, 0x78 \
} \
}
class NS_NO_VTABLE nsIDiscardableRunnable : public nsISupports {
public:
NS_DECLARE_STATIC_IID_ACCESSOR(NS_IDISCARDABLERUNNABLE_IID)
/**
* Called exactly once on a queued task only if nsIRunnable::Run() is not
* called.
*/
virtual void OnDiscard() = 0;
protected:
nsIDiscardableRunnable() = default;
virtual ~nsIDiscardableRunnable() = default;
};
NS_DEFINE_STATIC_IID_ACCESSOR(nsIDiscardableRunnable,
NS_IDISCARDABLERUNNABLE_IID)
#endif // XPCOM_THREADS_NSIDISCARDABLERUNNABLE_H_