Method PrefixScanEntries

tx_btree.go:352–393

PrefixScanEntries iterates over a key prefix at given bucket, prefix and limitNum. If reg is set a regular expression will be used to filter the found entries. LimitNum will limit the number of entries return. It will return keys and/or values based on the includeKeys and includeValues flags.

(bucket string, prefix []byte, reg string, offsetNum int, limitNum int, includeKeys, includeValues bool)

// found entries. LimitNum will limit the number of entries return. It will
// return keys and/or values based on the includeKeys and includeValues flags.
func (tx *Tx) PrefixScanEntries(bucket string, prefix []byte, reg string, offsetNum int, limitNum int, includeKeys, includeValues bool) (keys, values [][]byte, err error) {
	// This function is a bit awkward but that is to maintain backwards
	// compatibility while enabling the caller to pick and choose which
	// variation to call.
	if err := tx.checkTxIsClosed(); err != nil {
		return nil, nil, err
	}
	b, err := tx.db.bucketMgr.GetBucket(DataStructureBTree, bucket)
	if err != nil {
		return nil, nil, err
	}
	bucketId := b.Id

	xerr := func() error {
		// Return expected error types based on Scan/SearchScan.
		if reg == "" {
			return ErrPrefixScan
		}
		return ErrPrefixSearchScan
	}

	if idx, ok := tx.db.Index.BTree.exist(bucketId); ok {
		var records []*core.Record
		if reg == "" {
			records = idx.PrefixScan(prefix, offsetNum, limitNum)
		} else {
			records = idx.PrefixSearchScan(prefix, reg, offsetNum, limitNum)
		}
		keys, values, err = tx.getHintIdxDataItemsWrapper(records, limitNum, bucketId, includeKeys, includeValues)
		if err != nil {
			return nil, nil, xerr()
		}
	}

	if includeKeys && len(keys) == 0 {
		return nil, nil, xerr()
	}
	if includeValues && len(values) == 0 {
		return nil, nil, xerr()
	}
	return
}

// PrefixScan iterates over a key prefix at given bucket, prefix and limitNum.
// LimitNum will limit the number of entries return.