func (dl directoryLayer) checkVersion(rtr fdb.ReadTransaction, tr *fdb.Transaction) error {
version := rtr.Get(dl.rootNode.Sub([]byte("version"))).MustGet()
if version == nil {
if tr != nil {
dl.initializeDirectory(*tr)
}
return nil
}
var versions []int32
buf := bytes.NewBuffer(version)
for i := 0; i < 3; i++ {
var v int32
err := binary.Read(buf, binary.LittleEndian, &v)
if err != nil {
return errors.New("cannot determine directory version present in database")
}
versions = append(versions, v)
}
if versions[0] > _MAJORVERSION {
return fmt.Errorf("cannot load directory with version %d.%d.%d using directory layer %d.%d.%d", versions[0], versions[1], versions[2], _MAJORVERSION, _MINORVERSION, _MICROVERSION)
}
if versions[1] > _MINORVERSION && tr != nil /* aka write access allowed */ {
return fmt.Errorf("directory with version %d.%d.%d is read-only when opened using directory layer %d.%d.%d", versions[0], versions[1], versions[2], _MAJORVERSION, _MINORVERSION, _MICROVERSION)
}
return nil
}
func (n *node) layer(rtr fdb.ReadTransaction) fdb.FutureByteSlice {
if n._layer == nil {
fv := rtr.Get(n.subspace.Sub([]byte("layer")))
n._layer = fv
}
return n._layer
}
func (dl directoryLayer) find(rtr fdb.ReadTransaction, path []string) *node {
n := &node{dl.rootNode, []string{}, path, nil}
for i := range path {
n = &node{dl.nodeWithPrefix(rtr.Get(n.subspace.Sub(_SUBDIRS, path[i])).MustGet()), path[:i+1], path, nil}
if !n.exists() || bytes.Compare(n.layer(rtr).MustGet(), []byte("partition")) == 0 {
return n
}
}
return n
}
