// Close a query that was created with Prepare()
//
// This is called automaticly when the database is closed.
func (query *Query) Close() {
query.lock.Lock()
defer query.lock.Unlock()
if query.opened {
C.c_dbxml_query_free(query.query)
delete(query.db.queries, query.id)
query.db = nil
query.opened = false
}
}
// Prepare an XPATH query.
//
// The query can be run multiple times, and a running query can be cancelled by query.Cancel()
func (db *Db) Prepare(query string) (*Query, error) {
q := &Query{}
db.lock.Lock()
defer db.lock.Unlock()
if !db.opened {
return q, errclosed
}
cs := C.CString(query)
defer C.free(unsafe.Pointer(cs))
q.query = C.c_dbxml_prepare_query(db.db, cs)
if C.c_dbxml_get_prepared_error(q.query) != 0 {
defer C.c_dbxml_query_free(q.query)
return q, errors.New(C.GoString(C.c_dbxml_get_prepared_errstring(q.query)))
}
// No finalizer: query will be closed when database gets closed
q.opened = true
q.db = db
q.id = db.counter
db.counter++
db.queries[q.id] = q
return q, nil
}