func (t *tOps) newIterator(f *tFile, slice *util.Range, ro *opt.ReadOptions) iterator.Iterator {
c, err := t.lookup(f)
if err != nil {
return iterator.NewEmptyIterator(err)
}
iter := c.Value().(*table.Reader).NewIterator(slice, ro)
iter.SetReleaser(c)
return iter
}
// NewIterator returns an iterator for the latest snapshot of the
// uderlying DB.
// The returned iterator is not goroutine-safe, but it is safe to use
// multiple iterators concurrently, with each in a dedicated goroutine.
// It is also safe to use an iterator concurrently with modifying its
// underlying DB. The resultant key/value pairs are guaranteed to be
// consistent.
//
// Slice allows slicing the iterator to only contains keys in the given
// range. A nil Range.Start is treated as a key before all keys in the
// DB. And a nil Range.Limit is treated as a key after all keys in
// the DB.
//
// The iterator must be released after use, by calling Release method.
//
// Also read Iterator documentation of the leveldb/iterator package.
func (d *DB) NewIterator(slice *util.Range, ro *opt.ReadOptions) iterator.Iterator {
if err := d.ok(); err != nil {
return iterator.NewEmptyIterator(err)
}
p := d.newSnapshot()
defer p.Release()
return p.NewIterator(slice, ro)
}