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/*
* Copyright 1993 Network Computing Devices, Inc.
*
* Permission to use, copy, modify, distribute, and sell this software and its
* documentation for any purpose is hereby granted without fee, provided that
* the above copyright notice appear in all copies and that both that
* copyright notice and this permission notice appear in supporting
* documentation, and that the name Network Computing Devices, Inc. not be
* used in advertising or publicity pertaining to distribution of this
* software without specific, written prior permission.
*
* THIS SOFTWARE IS PROVIDED 'AS-IS'. NETWORK COMPUTING DEVICES, INC.,
* DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING WITHOUT
* LIMITATION ALL IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
* PARTICULAR PURPOSE, OR NONINFRINGEMENT. IN NO EVENT SHALL NETWORK
* COMPUTING DEVICES, INC., BE LIABLE FOR ANY DAMAGES WHATSOEVER, INCLUDING
* SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES, INCLUDING LOSS OF USE, DATA,
* OR PROFITS, EVEN IF ADVISED OF THE POSSIBILITY THEREOF, AND REGARDLESS OF
* WHETHER IN AN ACTION IN CONTRACT, TORT OR NEGLIGENCE, ARISING OUT OF OR IN
* CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*
* $NCDId: @(#)HandleEv.c,v 1.9 1993/08/11 17:01:58 greg Exp $
*/
/*
* This file contains utilities contains an event handler takes care of
* dispatching the various events that might come into an application. The
* idea is to hide most of the mainline activity so that simple applications
* don't have to fuss with things.
*
* For example, an application that wants to play a sound from a file or memory
* buffer asynchronously needs to wait for events telling it when it can
* write to the ImportElement in the flow.
*/
#include "Alibint.h"
void
AuHandleEvents(AuServer *aud)
{
int nevents;
AuEvent event;
while (1)
{
/* do our best to find an event */
nevents = _AuEventsQueued(aud, AuEventsQueuedAlready);
if (!nevents)
{
nevents = _AuEventsQueued(aud, AuEventsQueuedAfterFlush);
if (!nevents)
{
nevents = _AuEventsQueued(aud, AuEventsQueuedAfterReading);
if (!nevents)
return;
}
}
/* got one, now do something with it */
for (; nevents > 0; nevents--)
{
AuNextEvent(aud, AuTrue, &event); /* dequeue the event */
(void) AuDispatchEvent(aud, &event); /* go deal with it */
}
}
}
AuBool
AuDispatchEvent(
AuServer *aud,
AuEvent *event
)
{
AuBool result = AuFalse;
AuEventHandlerRec *handler = NULL, *next;
do
{
if ((handler = AuLookupEventHandler(aud, event, handler))
!= (AuEventHandlerRec *) NULL)
{
next = handler->next; /* could be removed by handler */
result |= (*(handler->callback)) (aud, event, handler);
handler = next;
}
} while (handler);
return result;
}
AuEventHandlerRec *
AuLookupEventHandler(
register AuServer *aud,
register AuEvent *event,
register AuEventHandlerRec *handler
)
{
/*
* From the given start location (NULL indicates beginning), walk down
* the handlers list looking for a match.
*/
if (!handler)
handler = aud->eventhandlerq;
/*
* This could be done more efficiently than a linear lookup, but there
* are relatively few events in the audio protocol, so the overhead
* should be acceptable.
*/
for (; handler; handler = handler->next)
{
if ((handler->mask & AuEventHandlerTypeMask) &&
(handler->type != event->type))
continue;
if ((handler->mask & AuEventHandlerIDMask) &&
(handler->id != event->auany.id))
continue;
break; /* got one! */
}
return handler;
}
AuEventHandlerRec *
AuRegisterEventHandler(
AuServer *aud,
AuMask mask,
int type,
AuID id,
AuEventHandlerCallback callback,
AuPointer data
)
{
AuEventHandlerRec *handler;
if (!(handler = (AuEventHandlerRec *) Aumalloc(sizeof(AuEventHandlerRec))))
return NULL;
handler->aud = aud;
handler->mask = mask;
handler->type = type;
handler->id = id;
handler->callback = callback;
handler->data = data;
_AuAddToLinkedList(aud->eventhandlerq, handler);
return handler;
}
void
AuUnregisterEventHandler(
AuServer *aud,
AuEventHandlerRec *handler
)
{
_AuRemoveFromLinkedList(aud->eventhandlerq, handler);
Aufree(handler);
}
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