コード例 #1
0
ファイル: reader.go プロジェクト: rht/go-datastore
// 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))
}
コード例 #2
0
ファイル: reader.go プロジェクト: rht/go-datastore
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
}