// NewIterator creates an iterator from the table.
//
// 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
// table. And a nil Range.Limit is treated as a key after all keys in
// the table.
//
// The returned iterator is not goroutine-safe and should be released
// when not used.
//
// Also read Iterator documentation of the leveldb/iterator package.
func (r *Reader) NewIterator(slice *util.Range, ro *opt.ReadOptions) iterator.Iterator {
r.mu.RLock()
defer r.mu.RUnlock()
if r.err != nil {
return iterator.NewEmptyIterator(r.err)
}
fillCache := !ro.GetDontFillCache()
indexBlock, rel, err := r.getIndexBlock(fillCache)
if err != nil {
return iterator.NewEmptyIterator(err)
}
index := &indexIter{
blockIter: r.newBlockIter(indexBlock, rel, slice, true),
tr: r,
slice: slice,
fillCache: !ro.GetDontFillCache(),
}
return iterator.NewIndexedIterator(index, opt.GetStrict(r.o, ro, opt.StrictReader))
}
func (r *Reader) find(key []byte, filtered bool, ro *opt.ReadOptions, noValue bool) (rkey, value []byte, err error) {
r.mu.RLock()
defer r.mu.RUnlock()
if r.err != nil {
err = r.err
return
}
indexBlock, rel, err := r.getIndexBlock(true)
if err != nil {
return
}
defer rel.Release()
index := r.newBlockIter(indexBlock, nil, nil, true)
defer index.Release()
if !index.Seek(key) {
err = index.Error()
if err == nil {
err = ErrNotFound
}
return
}
dataBH, n := decodeBlockHandle(index.Value())
if n == 0 {
r.err = r.newErrCorruptedBH(r.indexBH, "bad data block handle")
return
}
if filtered && r.filter != nil {
filterBlock, frel, ferr := r.getFilterBlock(true)
if ferr == nil {
if !filterBlock.contains(r.filter, dataBH.offset, key) {
frel.Release()
return nil, nil, ErrNotFound
}
frel.Release()
} else if !errors.IsCorrupted(ferr) {
err = ferr
return
}
}
data := r.getDataIter(dataBH, nil, r.verifyChecksum, !ro.GetDontFillCache())
defer data.Release()
if !data.Seek(key) {
err = data.Error()
if err == nil {
err = ErrNotFound
}
return
}
// Don't use block buffer, no need to copy the buffer.
rkey = data.Key()
if !noValue {
if r.bpool == nil {
value = data.Value()
} else {
// Use block buffer, and since the buffer will be recycled, the buffer
// need to be copied.
value = append([]byte{}, data.Value()...)
}
}
return
}