ttl_clock.go

// Copyright 2023-2024 Phus Lu. All rights reserved.

package lru

import (
	"sync"
	"sync/atomic"
	"time"
)

// clock is the number of seconds since January 1, 2024 UTC
// always use `atomic.LoadUint32(&clock)` for accessing clock value.
var clock uint32

var clockOnce sync.Once

const clockBase = 1704067200 // 2024-01-01T00:00:00Z

func clocking() {
	clockOnce.Do(func() {
		atomic.StoreUint32(&clock, uint32(time.Now().Unix()-clockBase))
		go func(clock *uint32) {
			for {
				for i := 0; i < 9; i++ {
					time.Sleep(100 * time.Millisecond)
					atomic.StoreUint32(clock, uint32(time.Now().Unix()-clockBase))
				}
				time.Sleep(100 * time.Millisecond)
				atomic.StoreUint32(clock, uint32(time.Now().Unix()-clockBase))
			}
		}(&clock)
	})
}