slot.go

// Copyright 2017 Granitic. All rights reserved.
// Use of this source code is governed by an Apache 2.0 license that can be found in the LICENSE file at the root of this project.

package timer

type Slot struct {
	root   *Timer
	length int
}

func NewSlot() *Slot {
	return &Slot{}
}

func (l *Slot) Front() *Timer {
	return l.root
}

func (l *Slot) Len() int {
	return l.length
}

func (l *Slot) Back() (el *Timer) {
	if nil != l.root {
		el = l.root.prev
	}
	return
}

func (l *Slot) Clear() {
	l.root = nil
	l.length = 0
}

func (l *Slot) Push(el *Timer) {
	if nil == l.root {
		el.prev = el
		el.next = el
		l.root = el
	} else {
		el.next = l.root
		el.prev = l.root.prev
		l.root.prev.next = el
		l.root.prev = el
	}

	el.list = l
	l.length++
	return
}

func (l *Slot) Pop() (el *Timer) {
	if nil == l.root {
		return
	}
	if l.root == l.root.next {
		el = l.root
		l.root = nil
	} else {
		el = l.root.prev
		el.prev.next = l.root
		l.root.prev = el.prev
	}

	el.list = nil
	l.length--
	return
}

func (l *Slot) Remove(el *Timer) *Timer {
	if nil == l.root || l != el.list {
		return nil
	}

	el.list = nil
	l.length--
	if l.root == el {
		if el == el.next {
			l.root = nil
			return nil
		}
		l.root = el.next
	}

	el.prev.next = el.next
	el.next.prev = el.prev
	return el.next
}