Darwin-Streaming-Server/CommonUtilitiesLib/IdleTask.h
Darren VanBuren 849723c9cf Add even more of the source
This should be about everything needed to build so far?
2017-03-07 17:14:16 -08:00

108 lines
3.3 KiB
C++

/*
*
* @APPLE_LICENSE_HEADER_START@
*
* Copyright (c) 1999-2008 Apple Inc. All Rights Reserved.
*
* This file contains Original Code and/or Modifications of Original Code
* as defined in and that are subject to the Apple Public Source License
* Version 2.0 (the 'License'). You may not use this file except in
* compliance with the License. Please obtain a copy of the License at
* http://www.opensource.apple.com/apsl/ and read it before using this
* file.
*
* The Original Code and all software distributed under the License are
* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
* Please see the License for the specific language governing rights and
* limitations under the License.
*
* @APPLE_LICENSE_HEADER_END@
*
*/
/*
File: IdleTask.h
Contains: IdleTasks are identical to normal tasks (see task.h) with one exception:
You can schedule them for timeouts. If you call SetIdleTimer
on one, after the time has elapsed the task object will receive an
OS_IDLE event.
*/
#ifndef _IDLETASK_H_
#define _IDLETASK_H_
#include "Task.h"
#include "OSThread.h"
#include "OSHeap.h"
#include "OSMutex.h"
#include "OSCond.h"
class IdleTask;
//merely a private implementation detail of IdleTask
class IdleTaskThread : private OSThread
{
private:
IdleTaskThread() : OSThread(), fHeapMutex() {}
virtual ~IdleTaskThread() { Assert(fIdleHeap.CurrentHeapSize() == 0); }
void SetIdleTimer(IdleTask *idleObj, SInt64 msec);
void CancelTimeout(IdleTask *idleObj);
virtual void Entry();
OSHeap fIdleHeap;
OSMutex fHeapMutex;
OSCond fHeapCond;
friend class IdleTask;
};
class IdleTask : public Task
{
public:
//Call Initialize before using this class
static void Initialize();
IdleTask() : Task(), fIdleElem() { this->SetTaskName("IdleTask"); fIdleElem.SetEnclosingObject(this); }
//This object does a "best effort" of making sure a timeout isn't
//pending for an object being deleted. In other words, if there is
//a timeout pending, and the destructor is called, things will get cleaned
//up. But callers must ensure that SetIdleTimer isn't called at the same
//time as the destructor, or all hell will break loose.
virtual ~IdleTask();
//SetIdleTimer:
//This object will receive an OS_IDLE event in the following number of milliseconds.
//Only one timeout can be outstanding, if there is already a timeout scheduled, this
//does nothing.
void SetIdleTimer(SInt64 msec) { sIdleThread->SetIdleTimer(this, msec); }
//CancelTimeout
//If there is a pending timeout for this object, this function cancels it.
//If there is no pending timeout, this function does nothing.
//Currently not supported because OSHeap doesn't support random remove
void CancelTimeout() { sIdleThread->CancelTimeout(this); }
private:
OSHeapElem fIdleElem;
//there is only one idle thread shared by all idle tasks.
static IdleTaskThread* sIdleThread;
friend class IdleTaskThread;
};
#endif