Blocking queue implementation

bqueue.go

package queue

import "sync"

type Message string

type Queue struct {
	wmu   sync.Mutex
	cmu   sync.Mutex
	slice []*Message
}

func New() *Queue {
	q := Queue{slice: []*Message{}}
	q.wmu.Lock()
	return &q
}

func (q *Queue) Size() int {
	q.cmu.Lock()
	defer q.cmu.Unlock()

	return len(q.slice)
}

func (q *Queue) Push(m *Message) {
	q.cmu.Lock()
	defer q.cmu.Unlock()

	l := len(q.slice)
	q.slice = append(q.slice, m)

	if l == 0 {
		q.wmu.Unlock()
	}
}

func (q *Queue) Pop() *Message {
	q.cmu.Lock()
	defer q.cmu.Unlock()

	if len(q.slice) == 0 {
		q.wmu.Lock()
	}
	m := q.pop()

	return m
}

func (q *Queue) pop() *Message {
	m := q.slice[0]
	q.slice = q.slice[1:]
	return m
}