// EncDatumFromBuffer initializes an EncDatum with an encoding that is
// possibly followed by other data. Similar to EncDatumFromEncoded,
// except that this function figures out where the encoding stops and returns a
// slice for the rest of the buffer.
func EncDatumFromBuffer(typ ColumnType, enc DatumEncoding, buf []byte) (EncDatum, []byte, error) {
switch enc {
case DatumEncoding_ASCENDING_KEY, DatumEncoding_DESCENDING_KEY:
encLen, err := encoding.PeekLength(buf)
if err != nil {
return EncDatum{}, nil, err
}
ed := EncDatumFromEncoded(typ, enc, buf[:encLen])
return ed, buf[encLen:], nil
case DatumEncoding_VALUE:
typeOffset, encLen, err := encoding.PeekValueLength(buf)
if err != nil {
return EncDatum{}, nil, err
}
ed := EncDatumFromEncoded(typ, enc, buf[typeOffset:encLen])
return ed, buf[encLen:], nil
default:
panic(fmt.Sprintf("unknown encoding %s", enc))
}
}
// SetFromBuffer initializes the EncDatum with an encoding that is possibly
// followed by other data. Similar to SetEncoded, except that this function
// figures out where the encoding stops and returns a slice for the rest of the
// buffer.
func (ed *EncDatum) SetFromBuffer(
typ ColumnType_Kind, enc DatumEncoding, buf []byte,
) (remaining []byte, err error) {
switch enc {
case DatumEncoding_ASCENDING_KEY, DatumEncoding_DESCENDING_KEY:
encLen, err := encoding.PeekLength(buf)
if err != nil {
return nil, err
}
ed.SetEncoded(typ, enc, buf[:encLen])
return buf[encLen:], nil
case DatumEncoding_VALUE:
typeOffset, encLen, err := encoding.PeekValueLength(buf)
if err != nil {
return nil, err
}
ed.SetEncoded(typ, enc, buf[typeOffset:encLen])
return buf[encLen:], nil
default:
panic(fmt.Sprintf("unknown encoding %s", ed.encoding))
}
}
// processValueTuple processes the given values (of columns family.ColumnIDs),
// setting values in the rf.row accordingly. The key is only used for logging.
func (rf *RowFetcher) processValueTuple(
family *ColumnFamilyDescriptor, kv client.KeyValue, debugStrings bool, prettyKeyPrefix string,
) (prettyKey string, prettyValue string, err error) {
prettyKey = prettyKeyPrefix
if debugStrings {
rf.prettyValueBuf.Reset()
}
tupleBytes, err := kv.Value.GetTuple()
if err != nil {
return "", "", err
}
var colIDDiff uint32
var lastColID ColumnID
for len(tupleBytes) > 0 {
_, _, colIDDiff, _, err = encoding.DecodeValueTag(tupleBytes)
if err != nil {
return "", "", err
}
colID := lastColID + ColumnID(colIDDiff)
lastColID = colID
idx, ok := rf.colIdxMap[colID]
if !ok || !rf.valNeededForCol[idx] {
// This column wasn't requested, so read its length and skip it.
_, len, err := encoding.PeekValueLength(tupleBytes)
if err != nil {
return "", "", err
}
tupleBytes = tupleBytes[len:]
if log.V(3) {
log.Infof(context.TODO(), "Scan %s -> [%d] (skipped)", kv.Key, colID)
}
continue
}
if debugStrings {
prettyKey = fmt.Sprintf("%s/%s", prettyKey, rf.desc.Columns[idx].Name)
}
var encValue EncDatum
encValue, tupleBytes, err =
EncDatumFromBuffer(rf.cols[idx].Type, DatumEncoding_VALUE, tupleBytes)
if err != nil {
return "", "", err
}
if debugStrings {
err := encValue.EnsureDecoded(&rf.alloc)
if err != nil {
return "", "", err
}
fmt.Fprintf(&rf.prettyValueBuf, "/%v", encValue.Datum)
}
if !rf.row[idx].IsUnset() {
panic(fmt.Sprintf("duplicate value for column %d", idx))
}
rf.row[idx] = encValue
if log.V(3) {
log.Infof(context.TODO(), "Scan %d -> %v", idx, encValue)
}
}
if debugStrings {
prettyValue = rf.prettyValueBuf.String()
}
return prettyKey, prettyValue, nil
}
// processValueTuple processes the given values (of columns family.ColumnIDs),
// setting values in the rf.row accordingly. The key is only used for logging.
func (rf *RowFetcher) processValueTuple(
family *ColumnFamilyDescriptor, kv client.KeyValue, debugStrings bool, prettyKeyPrefix string,
) (prettyKey string, prettyValue string, err error) {
prettyKey = prettyKeyPrefix
if debugStrings {
rf.prettyValueBuf.Reset()
}
tupleBytes, err := kv.Value.GetTuple()
if err != nil {
return "", "", err
}
var colIDDiff uint32
var value parser.Datum
var lastColID ColumnID
for len(tupleBytes) > 0 {
_, _, colIDDiff, _, err = encoding.DecodeValueTag(tupleBytes)
if err != nil {
return "", "", err
}
colID := lastColID + ColumnID(colIDDiff)
lastColID = colID
idx, ok := rf.colIdxMap[colID]
// TODO(dan): Ideally rowFetcher would generate EncDatums instead of Datums
// and that would make the logic simpler. We won't need valNeededForCol at
// all, it would be up to the user of the class to decide if they want to
// decode them or not.
if !ok || !rf.valNeededForCol[idx] {
// This column wasn't requested, so read its length and skip it.
_, i, err := encoding.PeekValueLength(tupleBytes)
if err != nil {
return "", "", err
}
tupleBytes = tupleBytes[i:]
if log.V(3) {
log.Infof(context.TODO(), "Scan %s -> [%d] (skipped)", kv.Key, colID)
}
continue
}
if debugStrings {
prettyKey = fmt.Sprintf("%s/%s", prettyKey, rf.desc.Columns[idx].Name)
}
kind := rf.cols[idx].Type.Kind.ToDatumType()
value, tupleBytes, err = DecodeTableValue(&rf.alloc, kind, tupleBytes)
if err != nil {
return "", "", err
}
if debugStrings {
fmt.Fprintf(&rf.prettyValueBuf, "/%v", value)
}
if rf.row[idx] != nil {
panic(fmt.Sprintf("duplicate value for column %d", idx))
}
rf.row[idx] = value
if log.V(3) {
log.Infof(context.TODO(), "Scan %d -> %v", idx, value)
}
}
if debugStrings {
prettyValue = rf.prettyValueBuf.String()
}
return prettyKey, prettyValue, nil
}