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/*
ChibiOS/GFX - Copyright (C) 2012
Joel Bodenmann aka Tectu <joel@unormal.org>
This file is part of ChibiOS/GFX.
ChibiOS/GFX is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
ChibiOS/GFX is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
/**
* @file src/gevent/gevent.c
* @brief GEVENT Driver code.
*
* @addtogroup GEVENT
* @{
*/
#include "ch.h"
#include "hal.h"
#include "gfx.h"
#if GFX_USE_GEVENT || defined(__DOXYGEN__)
#if GEVENT_ASSERT_NO_RESOURCE
#define GEVENT_ASSERT(x) assert(x)
#else
#define GEVENT_ASSERT(x)
#endif
/* This mutex protects access to our tables */
static MUTEX_DECL(geventMutex);
/* Our table of listener/source pairs */
static GSourceListener Assignments[GEVENT_MAX_SOURCE_LISTENERS];
/* Loop through the assignment table deleting this listener/source pair. */
/* Null is treated as a wildcard. */
static void deleteAssignments(GListener *pl, GSourceHandle gsh) {
GSourceListener *psl;
for(psl = Assignments; psl < Assignments+GEVENT_MAX_SOURCE_LISTENERS; psl++) {
if ((!pl || psl->pListener == pl) && (!gsh || psl->pSource == gsh)) {
if (chSemGetCounterI(&psl->pListener->waitqueue) < 0) {
chBSemWait(&psl->pListener->eventlock); // Obtain the buffer lock
psl->pListener->event.type = GEVENT_EXIT; // Set up the EXIT event
chSemSignal(&psl->pListener->waitqueue); // Wake up the listener
chBSemSignal(&psl->pListener->eventlock); // Release the buffer lock
}
psl->pListener = 0;
}
}
}
void geventListenerInit(GListener *pl) {
chSemInit(&pl->waitqueue, 0); // Next wait'er will block
chBSemInit(&pl->eventlock, FALSE); // Only one thread at a time looking at the event buffer
pl->callback = 0; // No callback active
pl->event.type = GEVENT_NULL; // Always safety
}
bool_t geventAttachSource(GListener *pl, GSourceHandle gsh, unsigned flags) {
GSourceListener *psl, *pslfree;
// Safety first
if (!pl || !gsh) {
GEVENT_ASSERT(FALSE);
return FALSE;
}
chMtxLock(&geventMutex);
// Check if this pair is already in the table (scan for a free slot at the same time)
pslfree = 0;
for(psl = Assignments; psl < Assignments+GEVENT_MAX_SOURCE_LISTENERS; psl++) {
if (pl == psl->pListener && gsh == psl->pSource) {
// Just update the flags
chBSemWait(&pl->eventlock); // Safety first - just in case a source is using it
psl->listenflags = flags;
chBSemSignal(&pl->eventlock); // Release this lock
chMtxUnlock();
return TRUE;
}
if (!pslfree && !psl->pListener)
pslfree = psl;
}
// A free slot was found - allocate it
if (pslfree) {
pslfree->pListener = pl;
pslfree->pSource = gsh;
pslfree->listenflags = flags;
pslfree->srcflags = 0;
}
chMtxUnlock();
GEVENT_ASSERT(pslfree != 0);
return pslfree != 0;
}
void geventDetachSource(GListener *pl, GSourceHandle gsh) {
if (pl && gsh) {
chMtxLock(&geventMutex);
deleteAssignments(pl, gsh);
if (!gsh && chSemGetCounterI(&pl->waitqueue) < 0) {
chBSemWait(&pl->eventlock); // Obtain the buffer lock
pl->event.type = GEVENT_EXIT; // Set up the EXIT event
chSemSignal(&pl->waitqueue); // Wake up the listener
chBSemSignal(&pl->eventlock); // Release the buffer lock
}
chMtxUnlock();
}
}
GEvent *geventEventWait(GListener *pl, systime_t timeout) {
if (pl->callback || chSemGetCounterI(&pl->waitqueue) < 0)
return 0;
return chSemWaitTimeout(&pl->waitqueue, timeout) == RDY_OK ? &pl->event : 0;
}
void geventRegisterCallback(GListener *pl, GEventCallbackFn fn, void *param) {
if (pl) {
chMtxLock(&geventMutex);
chBSemWait(&pl->eventlock); // Obtain the buffer lock
pl->param = param; // Set the param
pl->callback = fn; // Set the callback function
if (chSemGetCounterI(&pl->waitqueue) < 0) {
pl->event.type = GEVENT_EXIT; // Set up the EXIT event
chSemSignal(&pl->waitqueue); // Wake up the listener
}
chBSemSignal(&pl->eventlock); // Release the buffer lock
chMtxUnlock();
}
}
GSourceListener *geventGetSourceListener(GSourceHandle gsh, GSourceListener *lastlr) {
GSourceListener *psl;
// Safety first
if (!gsh)
return 0;
chMtxLock(&geventMutex);
// Unlock the last listener event buffer
if (lastlr)
chBSemSignal(&lastlr->pListener->eventlock);
// Loop through the table looking for attachments to this source
for(psl = lastlr ? (lastlr+1) : Assignments; psl < Assignments+GEVENT_MAX_SOURCE_LISTENERS; psl++) {
if (gsh == psl->pSource) {
chBSemWait(&psl->pListener->eventlock); // Obtain a lock on the listener event buffer
chMtxUnlock();
return psl;
}
}
chMtxUnlock();
return 0;
}
GEvent *geventGetEventBuffer(GSourceListener *psl) {
// We already know we have the event lock
return &psl->pListener->callback || chSemGetCounterI(&psl->pListener->waitqueue) < 0 ? &psl->pListener->event : 0;
}
void geventSendEvent(GSourceListener *psl) {
chMtxLock(&geventMutex);
if (psl->pListener->callback) { // This test needs to be taken inside the mutex
chMtxUnlock();
// We already know we have the event lock
psl->pListener->callback(psl->pListener->param, &psl->pListener->event);
} else {
// Wake up the listener
if (chSemGetCounterI(&psl->pListener->waitqueue) < 0)
chSemSignal(&psl->pListener->waitqueue);
chMtxUnlock();
}
}
void geventDetachSourceListeners(GSourceHandle gsh) {
chMtxLock(&geventMutex);
deleteAssignments(0, gsh);
chMtxUnlock();
}
#endif /* GFX_USE_GEVENT */
/** @} */
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