//
// FetchFirstKeyOfRemoteLinkBag is the entry point for retrieving links from
// a remote server-side side LinkBag. In general, this method should not be
// called by end users. Instead, end users should call FetchEntriesOfRemoteLinkBag
//
// TODO: make this an unexported func?
//
func FetchFirstKeyOfRemoteLinkBag(dbc *DBClient, linkBag *oschema.OLinkBag) (*oschema.OLink, error) {
dbc.buf.Reset()
err := writeCommandAndSessionId(dbc, REQUEST_SBTREE_BONSAI_FIRST_KEY)
if err != nil {
return nil, oerror.NewTrace(err)
}
err = writeLinkBagCollectionPointer(dbc.buf, linkBag)
if err != nil {
return nil, oerror.NewTrace(err)
}
// send to the OrientDB server
_, err = dbc.conx.Write(dbc.buf.Bytes())
if err != nil {
return nil, oerror.NewTrace(err)
}
/* ---[ Read Response ]--- */
err = readStatusCodeAndSessionId(dbc)
if err != nil {
return nil, oerror.NewTrace(err)
}
firstKeyBytes, err := rw.ReadBytes(dbc.conx)
if err != nil {
return nil, oerror.NewTrace(err)
}
var (
typeByte byte
typeSerde binserde.OBinaryTypeSerializer
)
typeByte = firstKeyBytes[0]
typeSerde = binserde.TypeSerializers[typeByte]
result, err := typeSerde.Deserialize(bytes.NewBuffer(firstKeyBytes[1:]))
if err != nil {
return nil, oerror.NewTrace(err)
}
firstLink, ok := result.(*oschema.OLink)
if !ok {
// TODO: fmt.Errorf is an anti-pattern
return nil, fmt.Errorf("Typecast error. Expected *oschema.OLink but is %T", result)
}
return firstLink, nil
}
//
// FetchEntriesOfRemoteLinkBag fills in the links of an OLinkBag that is remote
// (tree-based) rather than embedded. This function will fill in the links
// of the passed in OLinkBag, rather than returning the new links. The Links
// will have RIDs only, not full Records (ODocuments). If you then want the
// Records filled in, call the ResolveLinks function.
//
func FetchEntriesOfRemoteLinkBag(dbc *DBClient, linkBag *oschema.OLinkBag, inclusive bool) error {
var (
firstLink *oschema.OLink
linkSerde binserde.OBinaryTypeSerializer
err error
)
firstLink, err = FetchFirstKeyOfRemoteLinkBag(dbc, linkBag)
if err != nil {
return oerror.NewTrace(err)
}
dbc.buf.Reset()
err = writeCommandAndSessionId(dbc, REQUEST_SBTREE_BONSAI_GET_ENTRIES_MAJOR)
if err != nil {
return oerror.NewTrace(err)
}
err = writeLinkBagCollectionPointer(dbc.buf, linkBag)
if err != nil {
return oerror.NewTrace(err)
}
typeByte := byte(9)
linkSerde = binserde.TypeSerializers[typeByte] // the OLinkSerializer
linkBytes, err := linkSerde.Serialize(firstLink)
if err != nil {
return oerror.NewTrace(err)
}
err = rw.WriteBytes(dbc.buf, linkBytes)
if err != nil {
return oerror.NewTrace(err)
}
err = rw.WriteBool(dbc.buf, inclusive)
if err != nil {
return oerror.NewTrace(err)
}
// copied from Java client OSBTreeBonsaiRemote#fetchEntriesMajor
if dbc.binaryProtocolVersion >= 21 {
err = rw.WriteInt(dbc.buf, 128)
}
// send to the OrientDB server
_, err = dbc.conx.Write(dbc.buf.Bytes())
if err != nil {
return oerror.NewTrace(err)
}
/* ---[ Read Response ]--- */
err = readStatusCodeAndSessionId(dbc)
if err != nil {
return oerror.NewTrace(err)
}
linkEntryBytes, err := rw.ReadBytes(dbc.conx)
if err != nil {
return oerror.NewTrace(err)
}
// all the rest of the response from the server in in this byte slice so
// we can reset the dbc.buf and reuse it to deserialize the serialized links
dbc.buf.Reset()
// ignoring error since doc says this method panics rather than return
// non-nil error
n, _ := dbc.buf.Write(linkEntryBytes)
if n != len(linkEntryBytes) {
return fmt.Errorf("Unexpected error when writing bytes to bytes.Buffer")
}
nrecs, err := rw.ReadInt(dbc.buf)
if err != nil {
return oerror.NewTrace(err)
}
var result interface{}
nr := int(nrecs)
// loop over all the serialized links
for i := 0; i < nr; i++ {
result, err = linkSerde.Deserialize(dbc.buf)
if err != nil {
return oerror.NewTrace(err)
}
linkBag.AddLink(result.(*oschema.OLink))
// FIXME: for some reason the server returns a serialized link
// followed by an integer (so far always a 1 in my expts).
// Not sure what to do with this int, so ignore for now
intval, err := rw.ReadInt(dbc.buf)
if err != nil {
return oerror.NewTrace(err)
}
if intval != int32(1) {
ogl.Warnf("DEBUG: Found a use case where the val pair of a link was not 1: %d\n", intval)
}
}
return nil
}