/* A record arriving via the loopback now leaves the feedback network.
* Remove the detref structure and check for termination conditions. */
void SNetFeedbackLeave(snet_record_t *rec, landing_t *landing, fifo_t *detfifo)
{
snet_stack_t *stack;
detref_t *detref, *first;
trace(__func__);
// record must have a stack of detrefs
if ((stack = DATA_REC(rec, detref)) == NULL) {
SNetUtilDebugFatal("[%s]: missing stack.", __func__);
}
// stack must have at least one detref
if ((detref = SNetStackPop(stack)) == NULL) {
SNetUtilDebugFatal("[%s]: empty stack.", __func__);
}
if (SNetStackIsEmpty(stack)) {
SNetStackDestroy(stack);
DATA_REC(rec, detref) = NULL;
}
// detref must refer to this DetLeave node
if (detref->leave != landing) {
SNetUtilDebugFatal("[%s]: leave %p != landing %p.", __func__,
detref->leave, landing);
}
// reference counter must be at least two
if (detref->refcount < 2) {
SNetUtilDebugFatal("[%s]: refcnt %d < 1.", __func__, detref->refcount);
}
// decrease reference count
if (DETREF_DECR(detref) == 1) {
DETREF_DECR(detref);
}
assert(detref->refcount >= 0);
// pop detrefs in sequence which have no more records in the loopback left.
while ((first = SNetFifoPeekFirst(detfifo)) != NULL) {
// stop processing if more records to come for this sequence counter
if (first->refcount > 0) {
break;
}
SNetFifoGet(detfifo);
SNetFifoDone(&first->recfifo);
SNetDelete(first);
}
}
/* Check if there are any records in the dripback loop left. */
static bool DripBackCheckBusy(landing_dripback2_t *db2)
{
detref_t *first;
/* check if dripback loop is still active */
while ((first = SNetFifoPeekFirst(&db2->detfifo)) != NULL) {
BAR();
if (first->refcount > 0) {
break;
}
SNetFifoGet(&db2->detfifo);
SNetFifoDone(&first->recfifo);
SNetDelete(first);
}
return first ? true : false;
}
/* Check if there are any records in the feedback loop left. */
static void FeedbackCheckBusy(landing_feedback3_t *fb3)
{
detref_t *first;
/* check if feedback loop is still active */
while ((first = SNetFifoPeekFirst(&fb3->detfifo)) != NULL) {
if (first->refcount > 0) {
break;
}
SNetFifoGet(&fb3->detfifo);
SNetFifoDone(&first->recfifo);
SNetDelete(first);
}
if (first == NULL && fb3->terminate == FeedbackDraining) {
fb3->terminate = FeedbackTerminating;
}
}
/* DripBack process a record. */
void SNetNodeDripBack(snet_stream_desc_t *desc, snet_record_t *rec)
{
landing_t *land = desc->landing;
dripback_arg_t *darg = LAND_NODE_SPEC(land, dripback);
trace(__func__);
if (land->type == LAND_dripback1) {
landing_dripback1_t *db1 = LAND_SPEC(land, dripback1);
landing_dripback2_t *db2 = LAND_SPEC(db1->dripback2, dripback2);
SNetFifoPut(db1->recfifo, rec);
if (FAA(&db2->queued, 1) == 0) {
if (db1->controldesc == NULL) {
SNetPushLanding(desc, db1->dripback2);
db1->controldesc = SNetStreamOpen(darg->selfref, desc);
}
rec = SNetRecCreate(REC_wakeup);
SNetWrite(&db1->controldesc, rec, true);
}
}
else if (land->type == LAND_dripback2) {
landing_dripback2_t *db2 = LAND_SPEC(land, dripback2);
bool via_access = (DESC_STREAM(desc) == darg->selfref);
assert(via_access || DESC_STREAM(desc) == darg->dripback);
while (rec) {
switch (REC_DESCR( rec)) {
case REC_data:
/* Test if record should go to the instance. */
if (SNetFeedbackMatch( rec, darg->back_patterns, darg->guards)) {
if (via_access) {
/* Because record came from outside add a detref counter. */
assert(db2->detfifo.head->next == NULL);
SNetRecDetrefAdd(rec, ++(db2->entered), land, &db2->detfifo);
} else {
/* Record came from the instance. */
assert(DATA_REC(rec, detref));
}
if (db2->instdesc == NULL) {
/* Instance should come back to this landing. */
if (SNetTopLanding(desc) != land) {
SNetPushLanding(desc, land);
}
db2->instdesc = SNetStreamOpen(darg->instance, desc);
if (SNetTopLanding(desc) == land) {
SNetPopLanding(desc);
SNetLandingDone(land);
}
}
SNetWrite(&db2->instdesc, rec, false);
} else {
if (!via_access) {
/* Record leaves the dripback loop. */
assert(DATA_REC(rec, detref));
SNetFeedbackLeave(rec, land, &db2->detfifo);
}
if (db2->outdesc == NULL) {
db2->outdesc = SNetStreamOpen(darg->output, desc);
}
SNetWrite(&db2->outdesc, rec, false);
}
break;
case REC_wakeup:
assert(via_access);
SNetRecDestroy(rec);
break;
case REC_terminate:
assert(via_access);
assert(db2->terminate == DripBackInitial);
db2->terminate = DripBackDraining;
SNetRecDestroy(rec);
break;
case REC_detref:
if (DETREF_REC( rec, leave) == land &&
DETREF_REC( rec, location) == SNetDistribGetNodeId())
{
assert(!via_access);
SNetDetLeaveCheckDetref(rec, &db2->detfifo);
if (DETREF_REC( rec, detref) == SNetFifoPeekFirst(&db2->detfifo)) {
DripBackCheckBusy(db2);
}
SNetRecDestroy(rec);
} else {
assert(via_access);
if (db2->outdesc == NULL) {
db2->outdesc = SNetStreamOpen(darg->output, desc);
}
SNetWrite(&db2->outdesc, rec, false);
}
break;
case REC_sync:
SNetRecDestroy(rec);
break;
default:
SNetRecUnknownEnt(__func__, rec, darg->entity);
}
rec = NULL;
if (db2->state == DripBackBusy) {
if (DripBackCheckBusy(db2) == false) {
assert(db2->queued > 0);
if (SAF(&db2->queued, 1) == 0) {
db2->state = DripBackIdle;
} else {
rec = SNetFifoGet(&db2->recfifo);
assert(rec);
via_access = true;
}
}
} else {
assert(db2->state == DripBackIdle);
assert(SNetFifoPeekFirst(&db2->detfifo) == NULL);
if (db2->queued > 0) {
rec = SNetFifoGet(&db2->recfifo);
assert(rec);
via_access = true;
db2->state = DripBackBusy;
}
}
}
if (db2->terminate == DripBackDraining) {
if (db2->state == DripBackIdle) {
assert(db2->queued == 0 && DripBackCheckBusy(db2) == false);
db2->terminate = DripBackTerminated;
}
}
if (db2->terminate == DripBackTerminated) {
if (db2->instdesc) {
snet_stream_desc_t *desc = db2->instdesc;
db2->instdesc = NULL;
SNetDescDone(desc);
SNetLandingDone(land);
}
}
}
else {
assert(0);
}
}
