int uredo(BW *bw)
{
UNDOREC *upto;
UNDOREC *ptr;
UNDO *undo = bw->b->undo;
if (!undo)
return -1;
if (!undo->ptr)
return -1;
if (undo->ptr == &undo->recs)
return -1;
upto = undo->recs.link.prev->unit;
do {
ptr = undo->recs.link.prev;
pgoto(bw->cursor, ptr->where);
inredo = 1;
doundo(bw, ptr);
inredo = 0;
frrec(deque_f(UNDOREC, link, ptr)); /* Delete record created by undo command */
undo->ptr = undo->ptr->link.next;
} while (upto && upto != ptr);
/* We just deleted one undo record */
--undo->nrecs;
return 0;
}
int uundo(BW *bw)
{
UNDOREC *upto;
UNDO *undo = bw->b->undo;
if (!undo)
return -1;
if (!undo->nrecs)
return -1;
if (!undo->ptr) {
pgoto(bw->cursor, undo->recs.link.prev->where);
undo->ptr = &undo->recs;
/* If this return is uncommented, then uundo will jump
to where the undo is about to occur before actually
undoing anything */
/* return 0; */
}
if (undo->ptr->link.prev == &undo->recs)
return -1;
upto = undo->ptr->link.prev->unit;
do {
undo->ptr = undo->ptr->link.prev;
pgoto(bw->cursor, undo->ptr->where);
inundo = 1;
doundo(bw, undo->ptr);
inundo = 0;
} while (upto && upto != undo->ptr);
return 0;
}
/* Undo any frames written (but not committed) to the log */
int sqlite3WalUndo(Wal *pWal, int (*xUndo)(void *, Pgno), void *pUndoCtx)
{
return doundo(pWal,xUndo, pUndoCtx,1);
}
