Datum
_Slony_I_seqtrack(PG_FUNCTION_ARGS)
{
static AVLtree seqmem = AVL_INITIALIZER(seqtrack_cmp, seqtrack_free);
AVLnode *node;
SeqTrack_elem *elem;
int32 seqid;
int64 seqval;
seqid = PG_GETARG_INT32(0);
seqval = PG_GETARG_INT64(1);
/*
* Try to insert the sequence id into the AVL tree.
*/
if ((node = avl_insert(&seqmem, &seqid)) == NULL)
elog(ERROR, "Slony-I: unexpected NULL return from avl_insert()");
if (AVL_DATA(node) == NULL)
{
/*
* This is a new (not seen before) sequence. Create the element,
* remember the current lastval and return it to the caller.
*/
elem = (SeqTrack_elem *) malloc(sizeof(SeqTrack_elem));
elem->seqid = seqid;
elem->seqval = seqval;
AVL_SETDATA(node, elem);
PG_RETURN_INT64(seqval);
}
/*
* This is a sequence seen before. If the value has changed remember and
* return it. If it did not, return NULL.
*/
elem = AVL_DATA(node);
if (elem->seqval == seqval)
PG_RETURN_NULL();
else
elem->seqval = seqval;
PG_RETURN_INT64(seqval);
}
void
avl_dump(avl_tree *tree, avl_node *node, int level)
{
char space[1024];
memset(space, ' ', 1024);
space[level*4] = 0;
if (node == NULL) return;
avl_dump(tree, node->child[1], level+1);
printf("%s[%d]\n", space, ((intr*)AVL_DATA(node, tree))->data);
avl_dump(tree, node->child[0], level+1);
}