package stdapi

import (

"crypto/rand"

"crypto/sha1"

"fmt"

"reflect"

"runtime"

"strings"

"github.com/pkg/errors"

)

func coalesce(ss ...string) string {

for _, s := range ss {

if s != "" {

return s

}

}

return ""

}

func functionName(fn interface{}) string {

sig := runtime.FuncForPC(reflect.ValueOf(fn).Pointer()).Name()

parts := strings.Split(sig, ".")

name := parts[len(parts)-1]

name = strings.TrimSuffix(name, "-fm")

return name

}

func generateId(length int) (string, error) {

data := make([]byte, 1024)

if _, err := rand.Read(data); err != nil {

return "", errors.WithStack(err)

}

key := fmt.Sprintf("%x", sha1.Sum(data))

if len(key) < length {

return "", errors.WithStack(fmt.Errorf("key too long"))

}

return key[0:length], nil

}