// KeyToLocalIDs parses a key under a DataContext and returns instance, version and client ids.
func DataKeyToLocalIDs(k Key) (dvid.InstanceID, dvid.VersionID, dvid.ClientID, error) {
if k[0] != dataKeyPrefix {
return 0, 0, 0, fmt.Errorf("Cannot extract local IDs from a non-DataContext key")
}
instanceID := dvid.InstanceIDFromBytes(k[1 : 1+dvid.InstanceIDSize])
start := len(k) - dvid.VersionIDSize - dvid.ClientIDSize - 1
versionID := dvid.VersionIDFromBytes(k[start : start+dvid.VersionIDSize])
start += dvid.VersionIDSize
clientID := dvid.ClientIDFromBytes(k[start : start+dvid.ClientIDSize])
return instanceID, versionID, clientID, nil
}
// InstanceFromKey returns an InstanceID from a full key. Any DataContext is sufficient as receiver.
func (ctx *DataContext) InstanceFromKey(key Key) (dvid.InstanceID, error) {
if key == nil {
return 0, fmt.Errorf("Cannot extract DataContext instance from nil key")
}
if key[0] != dataKeyPrefix {
return 0, fmt.Errorf("Cannot extract DataContext version from different key type")
}
if len(key) < 5 {
return 0, fmt.Errorf("Cannot get instance from Key %v less than 5 bytes", key)
}
return dvid.InstanceIDFromBytes(key[1 : 1+dvid.InstanceIDSize]), nil
}
// Load the next ids to be used for RepoID, VersionID, and InstanceID.
func (m *repoManager) loadNewIDs() error {
var ctx storage.MetadataContext
value, err := m.store.Get(ctx, storage.NewTKey(newIDsKey, nil))
if err != nil {
return err
}
if len(value) != dvid.RepoIDSize+dvid.VersionIDSize+dvid.InstanceIDSize {
return fmt.Errorf("Bad value returned for new ids. Length %d bytes!", len(value))
}
pos := 0
m.repoID = dvid.RepoIDFromBytes(value[pos : pos+dvid.RepoIDSize])
pos += dvid.RepoIDSize
m.versionID = dvid.VersionIDFromBytes(value[pos : pos+dvid.VersionIDSize])
pos += dvid.VersionIDSize
m.instanceID = dvid.InstanceIDFromBytes(value[pos : pos+dvid.InstanceIDSize])
return nil
}
