// Copyright 2021 PingCAP, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// See the License for the specific language governing permissions and
// limitations under the License.

package executor

import "strings"

func setFromString(value string) []string {
	if len(value) == 0 {
		return nil
	}
	return strings.Split(value, ",")
}

// addToSet add a value to the set, e.g:
// addToSet("Select,Insert,Update", "Update") returns "Select,Insert,Update".
func addToSet(set []string, value string) []string {
	for _, v := range set {
		if v == value {
			return set
		}
	}
	return append(set, value)
}

// deleteFromSet delete the value from the set, e.g:
// deleteFromSet("Select,Insert,Update", "Update") returns "Select,Insert".
func deleteFromSet(set []string, value string) []string {
	for i, v := range set {
		if v == value {
			copy(set[i:], set[i+1:])
			return set[:len(set)-1]
		}
	}
	return set
}