func (store *MySQLStore) Filter(subjSearch, predSearch, objSearch argo.Term) (ch chan *argo.Triple) {
ch = make(chan *argo.Triple)
queryClauses := make([]string, 0)
queryValues := make([]interface{}, 0)
if subjSearch != nil {
subjectID := store.encodeSubject(subjSearch)
queryClauses = append(queryClauses, "subject = ?")
queryValues = append(queryValues, subjectID)
}
if predSearch != nil {
predicatePrefixID, predicateLocal := store.encodePredicate(predSearch)
queryClauses = append(queryClauses, "predicatePrefix = ?")
queryClauses = append(queryClauses, "predicateLocal = ?")
queryValues = append(queryValues, predicatePrefixID)
queryValues = append(queryValues, predicateLocal)
}
if objSearch != nil {
objectIsLiteral, objectID := store.encodePredicate(objSearch)
queryClauses = append(queryClauses, "objectIsLiteral = ?")
queryClauses = append(queryClauses, "object = ?")
queryValues = append(queryValues, objectIsLiteral)
queryValues = append(queryValues, objectID)
}
whereStr := ""
if len(queryClauses) > 0 {
whereStr = " WHERE " + strings.Join(queryClauses, " AND ")
}
resultChan, failChan := store.execute("SELECT subject, predicatePrefix, predicateLocal, objectIsLiteral, object FROM %s_triples"+whereStr, queryValues...)
go func() {
for row := range resultChan {
var subject, predicate, object argo.Term
if subjSearch == nil {
subject = store.decodeSubject(row[0].(uint64))
} else {
subject = subjSearch
}
if predSearch == nil {
predicate = store.decodePredicate(row[1].(uint64), row[2].(string))
} else {
predicate = predSearch
}
if objSearch == nil {
object = store.decodeObject(row[3].(uint8), row[4].(uint64))
} else {
object = objSearch
}
ch <- argo.NewTriple(subject, predicate, object)
}
<-failChan
close(ch)
}()
return ch
}
func (store *MySQLStore) decodeTriple(subjectID uint64, predicatePrefixID uint64, predicateLocal string, objectIsLiteral uint8, objectID uint64) (triple *argo.Triple) {
return argo.NewTriple(store.decodeSubject(subjectID), store.decodePredicate(predicatePrefixID, predicateLocal), store.decodeObject(objectIsLiteral, objectID))
}
