/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package extension

import (
	"container/list"
)

var (
	customShutdownCallbacks = list.New()
)

/**
 * AddCustomShutdownCallback
 * you should not make any assumption about the order.
 * For example, if you have more than one callbacks, and you wish the order is:
 * callback1()
 * callback2()
 * ...
 * callbackN()
 * Then you should put then together:
 * func callback() {
 *     callback1()
 *     callback2()
 *     ...
 *     callbackN()
 * }
 * I think the order of custom callbacks should be decided by the users.
 * Even though I can design a mechanism to support the ordered custom callbacks,
 * the benefit of that mechanism is low.
 * And it may introduce much complication for another users.
 */
func AddCustomShutdownCallback(callback func()) {
	customShutdownCallbacks.PushBack(callback)
}

// GetAllCustomShutdownCallbacks gets all custom shutdown callbacks
func GetAllCustomShutdownCallbacks() *list.List {
	return customShutdownCallbacks
}