docs/future/future.go

63 lines
1.3 KiB
Go

package future
import (
"bytes"
"crypto/sha256"
"fmt"
"io"
"math/rand"
"time"
)
func Seed() {
rand.Seed(time.Now().UTC().UnixNano())
}
func ComputeId(content io.Reader) (string, error) {
h := sha256.New()
if _, err := io.Copy(h, content); err != nil {
return "", err
}
return fmt.Sprintf("%x", h.Sum(nil)[:8]), nil
}
func HumanDuration(d time.Duration) string {
if seconds := int(d.Seconds()); seconds < 1 {
return "Less than a second"
} else if seconds < 60 {
return fmt.Sprintf("%d seconds", seconds)
} else if minutes := int(d.Minutes()); minutes == 1 {
return "About a minute"
} else if minutes < 60 {
return fmt.Sprintf("%d minutes", minutes)
} else if hours := int(d.Hours()); hours == 1 {
return "About an hour"
} else if hours < 48 {
return fmt.Sprintf("%d hours", hours)
} else if hours < 24*7*2 {
return fmt.Sprintf("%d days", hours/24)
} else if hours < 24*30*3 {
return fmt.Sprintf("%d weeks", hours/24/7)
} else if hours < 24*365*2 {
return fmt.Sprintf("%d months", hours/24/30)
}
return fmt.Sprintf("%d years", d.Hours()/24/365)
}
func randomBytes() io.Reader {
return bytes.NewBuffer([]byte(fmt.Sprintf("%x", rand.Int())))
}
func RandomId() string {
id, _ := ComputeId(randomBytes()) // can't fail
return id
}
func Go(f func() error) chan error {
ch := make(chan error)
go func() {
ch <- f()
}()
return ch
}