Function HScan

command/hashes.go:325–422

HScan incrementally iterate hash fields and associated values

(ctx *Context, txn *db.Transaction)

//HScan incrementally iterate hash fields and associated values
func HScan(ctx *Context, txn *db.Transaction) (OnCommit, error) {
	var (
		key        []byte
		cursor     []byte
		lastCursor = []byte("0")
		count      = uint64(defaultScanCount)
		kvs        = [][]byte{}
		pattern    []byte
		prefix     []byte
		isAll      bool
		err        error
	)
	key = []byte(ctx.Args[0])
	if strings.Compare(ctx.Args[1], "0") != 0 {
		cursor = []byte(ctx.Args[1])
	}

	// define return result
	result := func() {
		if _, err := resp.ReplyArray(ctx.Out, 2); err != nil {
			return
		}
		resp.ReplyBulkString(ctx.Out, string(lastCursor))
		if _, err := resp.ReplyArray(ctx.Out, len(kvs)); err != nil {
			return
		}
		for i := range kvs {
			resp.ReplyBulkString(ctx.Out, string(kvs[i]))
		}
	}
	hash, err := txn.Hash(key)
	if err != nil {
		if err == db.ErrTypeMismatch {
			return nil, ErrTypeMismatch
		}
		return nil, errors.New("ERR " + err.Error())
	}

	//check if hash is not exits return result
	if !hash.Exists() {
		return result, nil
	}

	if len(ctx.Args)%2 != 0 {
		return nil, ErrSyntax
	}

	for i := 2; i < len(ctx.Args); i += 2 {
		arg := strings.ToLower(ctx.Args[i])
		next := ctx.Args[i+1]
		switch arg {
		case "count":
			if count, err = strconv.ParseUint(next, 10, 64); err != nil {
				return nil, ErrInteger
			}
			if count > ScanMaxCount {
				count = ScanMaxCount
			}