mirror of
https://github.com/mozilla/gecko-dev.git
synced 2024-11-06 17:16:12 +00:00
176 lines
7.3 KiB
C
176 lines
7.3 KiB
C
/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
|
|
/*
|
|
* The contents of this file are subject to the Netscape Public License
|
|
* Version 1.0 (the "NPL"); you may not use this file except in
|
|
* compliance with the NPL. You may obtain a copy of the NPL at
|
|
* http://www.mozilla.org/NPL/
|
|
*
|
|
* Software distributed under the NPL is distributed on an "AS IS" basis,
|
|
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the NPL
|
|
* for the specific language governing rights and limitations under the
|
|
* NPL.
|
|
*
|
|
* The Initial Developer of this code under the NPL is Netscape
|
|
* Communications Corporation. Portions created by Netscape are
|
|
* Copyright (C) 1998 Netscape Communications Corporation. All Rights
|
|
* Reserved.
|
|
*/
|
|
|
|
/*
|
|
** File: pralarm.h
|
|
** Description: API to periodic alarms.
|
|
**
|
|
**
|
|
** Alarms are defined to invoke some client specified function at
|
|
** a time in the future. The notification may be a one time event
|
|
** or repeated at a fixed interval. The interval at which the next
|
|
** notification takes place may be modified by the client code only
|
|
** during the respective notification.
|
|
**
|
|
** The notification is delivered on a thread that is part of the
|
|
** alarm context (PRAlarm). The thread will inherit the priority
|
|
** of the Alarm creator.
|
|
**
|
|
** Any number of periodic alarms (PRAlarmID) may be created within
|
|
** the context of a single alarm (PRAlarm). The notifications will be
|
|
** scheduled as close to the desired time as possible.
|
|
**
|
|
** Repeating periodic notifies are expected to run at a fixed rate.
|
|
** That rate is expressed as some number of notifies per period where
|
|
** the period is much larger than a PRIntervalTime (see prinrval.h).
|
|
*/
|
|
|
|
#if !defined(pralarm_h)
|
|
#define pralarm_h
|
|
|
|
#include "prtypes.h"
|
|
#include "prinrval.h"
|
|
|
|
|
|
PR_BEGIN_EXTERN_C
|
|
|
|
/**********************************************************************/
|
|
/************************* TYPES AND CONSTANTS ************************/
|
|
/**********************************************************************/
|
|
|
|
typedef struct PRAlarm PRAlarm;
|
|
typedef struct PRAlarmID PRAlarmID;
|
|
|
|
typedef PRBool (PR_CALLBACK *PRPeriodicAlarmFn)(
|
|
PRAlarmID *id, void *clientData, PRUint32 late);
|
|
|
|
/**********************************************************************/
|
|
/****************************** FUNCTIONS *****************************/
|
|
/**********************************************************************/
|
|
|
|
/***********************************************************************
|
|
** FUNCTION: PR_CreateAlarm
|
|
** DESCRIPTION:
|
|
** Create an alarm context.
|
|
** INPUTS: void
|
|
** OUTPUTS: None
|
|
** RETURN: PRAlarm*
|
|
**
|
|
** SIDE EFFECTS:
|
|
** This creates an alarm context, which is an object used for subsequent
|
|
** notification creations. It also creates a thread that will be used to
|
|
** deliver the notifications that are expected to be defined. The client
|
|
** is resposible for destroying the context when appropriate.
|
|
** RESTRICTIONS:
|
|
** None.
|
|
** MEMORY: The object (PRAlarm) and a thread to support notifications.
|
|
** ALGORITHM: N/A
|
|
***********************************************************************/
|
|
PR_EXTERN(PRAlarm*) PR_CreateAlarm(void);
|
|
|
|
/***********************************************************************
|
|
** FUNCTION: PR_DestroyAlarm
|
|
** DESCRIPTION:
|
|
** Destroys the context created by PR_CreateAlarm().
|
|
** INPUTS: PRAlarm*
|
|
** OUTPUTS: None
|
|
** RETURN: PRStatus
|
|
**
|
|
** SIDE EFFECTS:
|
|
** This destroys the context that was created by PR_CreateAlarm().
|
|
** If there are any active alarms (PRAlarmID), they will be cancelled.
|
|
** Once that is done, the thread that was used to deliver the alarms
|
|
** will be joined.
|
|
** RESTRICTIONS:
|
|
** None.
|
|
** MEMORY: N/A
|
|
** ALGORITHM: N/A
|
|
***********************************************************************/
|
|
PR_EXTERN(PRStatus) PR_DestroyAlarm(PRAlarm *alarm);
|
|
|
|
/***********************************************************************
|
|
** FUNCTION: PR_SetAlarm
|
|
** DESCRIPTION:
|
|
** Creates a periodic notifier that is to be delivered to a specified
|
|
** function at some fixed interval.
|
|
** INPUTS: PRAlarm *alarm Parent alarm context
|
|
** PRIntervalTime period Interval over which the notifies
|
|
** are delivered.
|
|
** PRUint32 rate The rate within the interval that
|
|
** the notifies will be delivered.
|
|
** PRPeriodicAlarmFn function Entry point where the notifies
|
|
** will be delivered.
|
|
** OUTPUTS: None
|
|
** RETURN: PRAlarmID* Handle to the notifier just created
|
|
** or NULL if the request failed.
|
|
**
|
|
** SIDE EFFECTS:
|
|
** A periodic notifier is created. The notifications will be delivered
|
|
** by the alarm's internal thread at a fixed interval whose rate is the
|
|
** number of interrupts per interval specified. The first notification
|
|
** will be delivered as soon as possible, and they will continue until
|
|
** the notifier routine indicates that they should cease of the alarm
|
|
** context is destroyed (PR_DestroyAlarm).
|
|
** RESTRICTIONS:
|
|
** None.
|
|
** MEMORY: Memory for the notifier object.
|
|
** ALGORITHM: The rate at which notifications are delivered are stated
|
|
** to be "'rate' notifies per 'interval'". The exact time of
|
|
** the notification is computed based on a epoch established
|
|
** when the notifier was set. Each notification is delivered
|
|
** not ealier than the epoch plus the fixed rate times the
|
|
** notification sequence number. Such notifications have the
|
|
** potential to be late by not more than 'interval'/'rate'.
|
|
** The amount of lateness of one notification is taken into
|
|
** account on the next in an attempt to avoid long term slew.
|
|
***********************************************************************/
|
|
PR_EXTERN(PRAlarmID*) PR_SetAlarm(
|
|
PRAlarm *alarm, PRIntervalTime period, PRUint32 rate,
|
|
PRPeriodicAlarmFn function, void *clientData);
|
|
|
|
/***********************************************************************
|
|
** FUNCTION: PR_ResetAlarm
|
|
** DESCRIPTION:
|
|
** Resets an existing alarm.
|
|
** INPUTS: PRAlarmID *id Identify of the notifier.
|
|
** PRIntervalTime period Interval over which the notifies
|
|
** are delivered.
|
|
** PRUint32 rate The rate within the interval that
|
|
** the notifies will be delivered.
|
|
** OUTPUTS: None
|
|
** RETURN: PRStatus Indication of completion.
|
|
**
|
|
** SIDE EFFECTS:
|
|
** An existing alarm may have its period and rate redefined. The
|
|
** additional side effect is that the notifier's epoch is recomputed.
|
|
** The first notification delivered by the newly refreshed alarm is
|
|
** defined to be 'interval'/'rate' from the time of the reset.
|
|
** RESTRICTIONS:
|
|
** This function may only be called in the notifier for that alarm.
|
|
** MEMORY: N/A.
|
|
** ALGORITHM: See PR_SetAlarm().
|
|
***********************************************************************/
|
|
PR_EXTERN(PRStatus) PR_ResetAlarm(
|
|
PRAlarmID *id, PRIntervalTime period, PRUint32 rate);
|
|
|
|
PR_END_EXTERN_C
|
|
|
|
#endif /* !defined(pralarm_h) */
|
|
|
|
/* prinrval.h */
|