GEVENT, GTIMER & GINPUT subsystems

GEVENT - for passing event structures from Sources to Listeners
GTIMER - thread context based once-off and periodic timers.
GINPUT - extensible, multiple device-type, input sub-system.
gevent & gtimer are code complete, ginput is definition complete but not
code complete.

1 files changed, 216 insertions, 0 deletions

diff --git a/src/gevent.c b/src/gevent.c
new file mode 100644
index 00000000..bfda6d53
--- /dev/null
+++ b/src/gevent.c
@@ -0,0 +1,216 @@
+/*

+    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.c

+ * @brief   GEVENT Driver code.

+ *

+ * @addtogroup GEVENT

+ * @{

+ */

+#include "ch.h"

+#include "hal.h"

+#include "gevent.h"

+

+#ifndef _GEVENT_C

+#define _GEVENT_C

+

+#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[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+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;

+		}

+	}

+}

+

+/* Create a Listener.

+ *	If insufficient resources are available it will either assert or return NULL

+ *	depending on the value of GEVENT_ASSERT_NO_RESOURCE.

+ */

+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->event.type = GEVENT_NULL;			// Always safety

+}

+

+/* Attach a source to a listener.

+ *	Flags are interpreted by the source when generating events for each listener.

+ *	If this source is already assigned to the listener it will update the flags.

+ *	If insufficient resources are available it will either assert or return FALSE

+ *	depending on the value of GEVENT_ASSERT_NO_RESOURCE.

+ */

+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+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;

+}

+

+/* Detach a source from a listener

+ *	If gsh is NULL detach all sources from this listener and if there is still

+ *		a thread waiting for events on this listener, it is sent the exit event.

+ */

+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();

+	}

+}

+

+/* Wait for an event on a listener from an assigned source.

+ *		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.

+ * timeout specifies the time to wait in system ticks.

+ *		TIME_INFINITE means no timeout - wait forever for an event.

+ *		TIME_IMMEDIATE means return immediately

+ * Returns NULL on timeout.

+ * Note: The GEvent buffer is staticly allocated within the GListener so the event does not

+ *			need to be dynamicly freed however it will get overwritten by the next call to

+ *			this routine.

+ */

+GEvent *geventEventWait(GListener *pl, systime_t timeout) {

+	return chSemWaitTimeout(&pl->waitqueue, timeout) == RDY_OK ? &pl->event : 0;

+}

+

+/* Called by a source with a possible event to get a listener record.

+ *	'lastlr' should be NULL on the first call and thereafter the result of the previous call.

+ *	It will return NULL when there are no more listeners for this source.

+ */

+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+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;

+}

+

+/* Get the event buffer from the GSourceListener.

+ *	Returns NULL if the listener is not currently listening.

+ *	A NULL return allows the source to record (perhaps in glr->scrflags) that the listener has missed events.

+ *	This can then be notified as part of the next event for the listener.

+ *	The buffer can only be accessed untill the next call to geventGetSourceListener or geventSendEvent

+ */

+GEvent *geventGetEventBuffer(GSourceListener *psl) {

+	// We already know we have the event lock

+	return chSemGetCounterI(&psl->pListener->waitqueue) < 0 ? &psl->pListener->event : 0;

+}

+

+/* Called by a source to indicate the listener's event buffer has been filled.

+ *	After calling this function the source must not reference in fields in the GSourceListener or the event buffer.

+ */

+void geventSendEvent(GSourceListener *psl) {

+	chMtxLock(&geventMutex);

+	// Wake up the listener

+	if (chSemGetCounterI(&psl->pListener->waitqueue) < 0)

+		chSemSignal(&psl->pListener->waitqueue);

+	chMtxUnlock();

+}

+

+/* Detach any listener that has this source attached */

+void geventDetachSourceListeners(GSourceHandle gsh) {

+	chMtxLock(&geventMutex);

+	deleteAssignments(0, gsh);

+	chMtxUnlock();

+}

+

+#endif /* GFX_USE_GEVENT */

+

+#endif /* _GEVENT_C */

+/** @} */