diff options
Diffstat (limited to 'src/gevent.c')
| -rw-r--r-- | src/gevent.c | 54 |
1 files changed, 49 insertions, 5 deletions
diff --git a/src/gevent.c b/src/gevent.c index d9c7e4f1..0a18eca2 100644 --- a/src/gevent.c +++ b/src/gevent.c @@ -71,6 +71,7 @@ static void deleteAssignments(GListener *pl, GSourceHandle gsh) { 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
}
@@ -165,9 +166,45 @@ void geventDetachSource(GListener *pl, GSourceHandle gsh) { * @return NULL on timeout
*/
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;
}
+/* @brief Register a callback for an event on a listener from an assigned source.
+ * @details The type of the event should be checked (pevent->type) and then pevent should be typecast to the
+ * actual event type if it needs to be processed.
+ *
+ * @params[in] pl The Listener
+ * @params[in] fn The function to call back
+ * @params[in] param A parameter to pass the callback function
+ *
+ * @note The GEvent buffer is valid only during the time of the callback. The callback MUST NOT save
+ * a pointer to the buffer for use outside the callback.
+ * @note An existing callback function is de-registered by passing a NULL for 'fn'. Any existing
+ * callback function is replaced. Any thread currently waiting using geventEventWait will be sent the exit event.
+ * @note Callbacks occur in a thread context but stack space must be kept to a minumum and
+ * the callback must process quickly as all other events are performed on a single thread.
+ * @note In the callback function you should never call ANY event functions using your own GListener handle
+ * as it WILL create a deadlock and lock the system up.
+ * @note Applications should not use this call - geventEventWait() is the preferred mechanism for an
+ * application. This call is provided for GUI objects that may not have their own thread.
+ */
+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();
+ }
+}
+
/**
* @brief Called by a source with a possible event to get a listener record.
* @details @p lastlr should be NULL on the first call and thereafter the result of the previous call.
@@ -215,7 +252,7 @@ GSourceListener *geventGetSourceListener(GSourceHandle gsh, GSourceListener *las */
GEvent *geventGetEventBuffer(GSourceListener *psl) {
// We already know we have the event lock
- return chSemGetCounterI(&psl->pListener->waitqueue) < 0 ? &psl->pListener->event : 0;
+ return &psl->pListener->callback || chSemGetCounterI(&psl->pListener->waitqueue) < 0 ? &psl->pListener->event : 0;
}
/**
@@ -226,10 +263,17 @@ GEvent *geventGetEventBuffer(GSourceListener *psl) { */
void geventSendEvent(GSourceListener *psl) {
chMtxLock(&geventMutex);
- // Wake up the listener
- if (chSemGetCounterI(&psl->pListener->waitqueue) < 0)
- chSemSignal(&psl->pListener->waitqueue);
- chMtxUnlock();
+ 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();
+ }
}
/**
|