71 lines
1.7 KiB
Go
71 lines
1.7 KiB
Go
// Copyright 2016 The Gogs Authors. All rights reserved.
|
|
// Use of this source code is governed by a MIT-style
|
|
// license that can be found in the LICENSE file.
|
|
|
|
package sync
|
|
|
|
import (
|
|
"github.com/unknwon/com"
|
|
)
|
|
|
|
// UniqueQueue is a queue which guarantees only one instance of same
|
|
// identity is in the line. Instances with same identity will be
|
|
// discarded if there is already one in the line.
|
|
//
|
|
// This queue is particularly useful for preventing duplicated task
|
|
// of same purpose.
|
|
type UniqueQueue struct {
|
|
table *StatusTable
|
|
queue chan string
|
|
}
|
|
|
|
// NewUniqueQueue initializes and returns a new UniqueQueue object.
|
|
func NewUniqueQueue(queueLength int) *UniqueQueue {
|
|
if queueLength <= 0 {
|
|
queueLength = 100
|
|
}
|
|
|
|
return &UniqueQueue{
|
|
table: NewStatusTable(),
|
|
queue: make(chan string, queueLength),
|
|
}
|
|
}
|
|
|
|
// Queue returns channel of queue for retrieving instances.
|
|
func (q *UniqueQueue) Queue() <-chan string {
|
|
return q.queue
|
|
}
|
|
|
|
// Exist returns true if there is an instance with given identity
|
|
// exists in the queue.
|
|
func (q *UniqueQueue) Exist(id interface{}) bool {
|
|
return q.table.IsRunning(com.ToStr(id))
|
|
}
|
|
|
|
// AddFunc adds new instance to the queue with a custom runnable function,
|
|
// the queue is blocked until the function exits.
|
|
func (q *UniqueQueue) AddFunc(id interface{}, fn func()) {
|
|
if q.Exist(id) {
|
|
return
|
|
}
|
|
|
|
idStr := com.ToStr(id)
|
|
q.table.lock.Lock()
|
|
q.table.pool[idStr] = struct{}{}
|
|
if fn != nil {
|
|
fn()
|
|
}
|
|
q.table.lock.Unlock()
|
|
q.queue <- idStr
|
|
}
|
|
|
|
// Add adds new instance to the queue.
|
|
func (q *UniqueQueue) Add(id interface{}) {
|
|
q.AddFunc(id, nil)
|
|
}
|
|
|
|
// Remove removes instance from the queue.
|
|
func (q *UniqueQueue) Remove(id interface{}) {
|
|
q.table.Stop(com.ToStr(id))
|
|
}
|