// Find finds key/value pair whose key is greater than or equal to the
// given key. It returns ErrNotFound if the table doesn't contain
// such pair.
//
// The caller should not modify the contents of the returned slice, but
// it is safe to modify the contents of the argument after Find returns.
func (r *Reader) Find(key []byte, ro *opt.ReadOptions) (rkey, value []byte, err error) {
if r.err != nil {
err = r.err
return
}
indexBlock, rel, err := r.readBlockCached(r.indexBH, true, true)
if err != nil {
return
}
defer rel.Release()
index := indexBlock.newIterator(nil, true, nil)
defer index.Release()
if !index.Seek(key) {
err = index.Error()
if err == nil {
err = ErrNotFound
}
return
}
dataBH, n := decodeBlockHandle(index.Value())
if n == 0 {
err = errors.New("leveldb/table: Reader: invalid table (bad data block handle)")
return
}
if r.filter != nil {
filterBlock, rel, ferr := r.readFilterBlockCached(r.filterBH, true)
if ferr == nil {
if !filterBlock.contains(dataBH.offset, key) {
rel.Release()
return nil, nil, ErrNotFound
}
rel.Release()
}
}
data := r.getDataIter(dataBH, nil, ro.GetStrict(opt.StrictBlockChecksum), !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()
// Use block buffer, and since the buffer will be recycled, the buffer
// need to be copied.
value = append([]byte{}, data.Value()...)
return
}
// 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 {
if r.err != nil {
return iterator.NewEmptyIterator(r.err)
}
fillCache := !ro.GetDontFillCache()
b, rel, err := r.readBlockCached(r.indexBH, true, fillCache)
if err != nil {
return iterator.NewEmptyIterator(err)
}
index := &indexIter{
blockIter: b.newIterator(slice, true, rel),
slice: slice,
checksum: ro.GetStrict(opt.StrictBlockChecksum),
fillCache: !ro.GetDontFillCache(),
}
return iterator.NewIndexedIterator(index, r.strictIter || ro.GetStrict(opt.StrictIterator), false)
}
