func (t *Tree) Get(ro *levigo.ReadOptions, id int) (*Node, error) {
if ro == nil {
ro = levigo.NewReadOptions()
defer ro.Close()
}
b := int2b(id)
dat, err := t.DB.Get(ro, b)
if err != nil {
return nil, err
}
res := new(Node)
json.Unmarshal(dat, res)
return res, nil
}
// NewIterator creates a new levigoIterator, which follows the Iterator
// interface.
//
// Important notes:
//
// For each of the iterator methods that have a return signature of (ok bool),
// if ok == false, the iterator may not be used any further and must be closed.
// Further work with the database requires the creation of a new iterator. This
// is due to LevelDB and Levigo design. Please refer to Jeff and Sanjay's notes
// in the LevelDB documentation for this behavior's rationale.
//
// The returned iterator must explicitly be closed; otherwise non-managed memory
// will be leaked.
//
// The iterator is optionally snapshotable.
func (l *LevelDBPersistence) NewIterator(snapshotted bool) Iterator {
var (
snapshot *levigo.Snapshot
readOptions *levigo.ReadOptions
iterator *levigo.Iterator
)
if snapshotted {
snapshot = l.storage.NewSnapshot()
readOptions = levigo.NewReadOptions()
readOptions.SetSnapshot(snapshot)
iterator = l.storage.NewIterator(readOptions)
} else {
iterator = l.storage.NewIterator(l.readOptions)
}
return &levigoIterator{
creationTime: time.Now(),
iterator: iterator,
readOptions: readOptions,
snapshot: snapshot,
storage: l.storage,
}
}
