traefik/vendor/github.com/Microsoft/ApplicationInsights-Go/appinsights/concurrentrandom.go
2018-07-11 09:08:03 +02:00

45 lines
875 B
Go

package appinsights
import (
"encoding/base64"
"math/rand"
"sync/atomic"
"time"
"unsafe"
)
type concurrentRandom struct {
channel chan string
random *rand.Rand
}
var randomGenerator *concurrentRandom
func newConcurrentRandom() *concurrentRandom {
source := rand.NewSource(time.Now().UnixNano())
return &concurrentRandom{
channel: make(chan string, 4),
random: rand.New(source),
}
}
func (generator *concurrentRandom) run() {
buf := make([]byte, 8)
for {
generator.random.Read(buf)
generator.channel <- base64.StdEncoding.EncodeToString(buf)
}
}
func randomId() string {
if randomGenerator == nil {
r := newConcurrentRandom()
if atomic.CompareAndSwapPointer((*unsafe.Pointer)(unsafe.Pointer(&randomGenerator)), unsafe.Pointer(nil), unsafe.Pointer(r)) {
go r.run()
} else {
close(r.channel)
}
}
return <-randomGenerator.channel
}