windows-nt/Source/XPSP1/NT/termsrv/remdsk/rds/t120/mst120/alarm.cpp
2020-09-26 16:20:57 +08:00

159 lines
3.9 KiB
C++

#include "precomp.h"
#include "fsdiag.h"
DEBUG_FILEZONE(ZONE_T120_GCCNC);
/*
* alarm.cpp
*
* Copyright (c) 1995 by Databeam Corporation, Lexington, KY
*
* Abstract:
* This is the implementation file for the Alarm class. Objects of this
* class are used when the creator wishes to make sure that a certain
* activity doesn't exceed a certain amount of time.
*
* By convention, an Alarm object is created with the time limitation
* passed in as the only parameter to the constructor. The creator can
* then periodically ask the Alarm object if it has expired. This hides
* all time maintenance code from the creator.
*
* Note that the Alarm class is PASSIVE, meaning that it will not call
* back into its creator when the specified time is exceeded. This
* capability could be added at a future data. if desirable. Right now,
* the creator MUST call into an Alarm object to ask it if it has expired.
*
* Private Data:
* Duration
* This refers to the original duration of the alarm. It is kept
* around to allow the creator to reset the alarm without having to
* respecify the duration.
* Expiration_Time
* This is the time (in clock ticks) upon which the alarm will expire.
* Whenever the alarm is asked if it has expired, it checks the current
* system clock against this value.
* Expired
* This is a boolean flag that indicates whether or not the alarm has
* already expired. This prevents the object from repeatedly checking
* the system clock if the timer has already expired.
*
* Caveats:
* None
*
* Author:
* James P. Galvin, Jr.
*
* Revision History:
* 09JAN95 jpg Original
*/
#include "alarm.h"
/*
* Alarm ()
*
* Public
*
* Function Description
* This is the constructor for the Alarm class. It calls Set to initialize
* all instance variables, and calculate the first expiration time value
* based on the specified duration.
*/
CAlarm::CAlarm(UINT nDuration)
{
Set(nDuration);
}
/*
* ~Alarm ()
*
* Public
*
* Function Description
* This is the destructor for the Alarm class. It currently does nothing.
*/
/*
* void Set ()
*
* Public
*
* Function Description
* This function initializes the alarm duration instance variable and
* calls Reset to ready the alarm for use.
*/
void CAlarm::Set(UINT nDuration)
{
m_nDuration = nDuration;
/*
* Call Reset to initialize remaining instance variables and ready the
* alarm for use.
*/
Reset();
}
/*
* void Reset ()
*
* Public
*
* Function Description
* This function calculate an expiration time value based on the specified
* duration and marks the alarm as unexpired.
*/
void CAlarm::Reset(void)
{
/*
* Determine the expiration time by adding the alarm duration to the
* current time.
*/
m_nStartTime = (UINT) ::GetTickCount();
m_fExpired = FALSE;
}
/*
* void Expire ()
*
* Public
*
* Function Description
* This function can be used to expire an alarm prematurely. This might
* be useful if the alarm is used to determine whether or not to perform
* an action, and the caller decides to inhibit the action for reasons
* other than time.
*/
/*
* BOOL IsExpired ()
*
* Public
*
* Function Description
* This function is used to check an alarm to see if it has expired.
*/
BOOL CAlarm::IsExpired(void)
{
/*
* See if the alarm has already expired before checking it again.
*/
// LONCHANC: The alarm object is totally bogus. We check for expiration
// only when we are sending a PDU out. However, when it expires, it is
// possible that there is no PDU to send. In this case, no one will know
// this alarm is expired. This means some actions will not be taken in time.
// Now, make it always expired because it did not work at all before and
// most of time it returned "expired."
#if 1
m_fExpired = TRUE;
#else
if (! m_fExpired)
{
if (m_nStartTime + m_nDuration <= (UINT) ::GetTickCount())
{
m_fExpired = TRUE;
}
}
#endif
return m_fExpired;
}