Agedge_t *agnxtin(Agraph_t * g, Agedge_t * e)
{
Agnode_t *n;
Agsubnode_t *sn;
Agedge_t *f = NILedge;
n = AGHEAD(e);
sn = agsubrep(g, n);
if (sn) {
dtrestore(g->e_seq, sn->in_seq);
f = (Agedge_t *) dtnext(g->e_seq, e);
sn->in_seq = dtextract(g->e_seq);
}
return f;
}
Dtmethod_t *dtmethod(Dt_t *dt, Dtmethod_t *meth) {
Dtlink_t *list;
Dtdisc_t *disc = dt->disc;
Dtmethod_t *oldmt = dt->meth;
Dtdata_t *newdt, *olddt = dt->data;
if (!meth || meth == oldmt) return oldmt;
/* ask discipline if switching to new method is ok */
if (disc->eventf && (*disc->eventf)(dt, DT_METH, (void *)meth, disc) < 0) return NULL;
list = dtextract(dt); /* extract elements out of dictionary */
/* try to create internal structure for new method */
if (dt->searchf == oldmt->searchf) { /* ie, not viewpathing */
dt->searchf = meth->searchf;
}
dt->meth = meth;
dt->data = NULL;
if ((*dt->meth->eventf)(dt, DT_OPEN, NULL) < 0) {
newdt = NULL;
} else {
newdt = dt->data;
}
/* see what need to be done to data of the old method */
if (dt->searchf == meth->searchf) dt->searchf = oldmt->searchf;
dt->meth = oldmt;
dt->data = olddt;
if (newdt) { // switch was successful, remove old data
(void)(*dt->meth->eventf)(dt, DT_CLOSE, NULL);
if (dt->searchf == oldmt->searchf) dt->searchf = meth->searchf;
dt->meth = meth;
dt->data = newdt;
dtrestore(dt, list);
return oldmt;
}
// Switch failed, restore dictionary to previous states.
dtrestore(dt, list);
return NULL;
}
