evio/internal/notequeue.go

48 lines
879 B
Go

// Copyright 2018 Joshua J Baker. All rights reserved.
// Use of this source code is governed by an MIT-style
// license that can be found in the LICENSE file.
package internal
import "sync"
// this is a good candiate for a lock-free structure.
type noteQueue struct {
mu sync.Mutex
notes []interface{}
}
func (q *noteQueue) Add(note interface{}) (one bool) {
q.mu.Lock()
q.notes = append(q.notes, note)
n := len(q.notes)
q.mu.Unlock()
return n == 1
}
func (q *noteQueue) ForEach(iter func(note interface{}) error) error {
q.mu.Lock()
if len(q.notes) == 0 {
q.mu.Unlock()
return nil
}
notes := q.notes
q.notes = nil
q.mu.Unlock()
for _, note := range notes {
if err := iter(note); err != nil {
return err
}
}
q.mu.Lock()
if q.notes == nil {
for i := range notes {
notes[i] = nil
}
q.notes = notes[:0]
}
q.mu.Unlock()
return nil
}