go-stack/data/stringify.go at master · subchen/go-stack · GitHub

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package data

import (

"bytes"

"fmt"

"io"

"reflect"

)

// Stringify attempts to create a reasonable string representation of types.

// It does things like resolve pointers to their values and omits struct fields with nil values.

func Stringify(message interface{}) string {

var buf bytes.Buffer

v := reflect.ValueOf(message)

stringifyValue(&buf, v)

return buf.String()

}

// stringifyValue was heavily inspired by the goprotobuf library.

func stringifyValue(w io.Writer, val reflect.Value) {

if val.Kind() == reflect.Ptr && val.IsNil() {

w.Write([]byte("<nil>"))

return

}

v := reflect.Indirect(val)

switch v.Kind() {

case reflect.String:

fmt.Fprintf(w, `"%s"`, v)

case reflect.Slice:

w.Write([]byte{'['})

for i := 0; i < v.Len(); i++ {

if i > 0 {

w.Write([]byte{' '})

}

stringifyValue(w, v.Index(i))

}

w.Write([]byte{']'})

return

case reflect.Struct:

if v.Type().Name() != "" {

w.Write([]byte(v.Type().String()))

}

w.Write([]byte{'{'})

var sep bool

for i := 0; i < v.NumField(); i++ {

fv := v.Field(i)

if fv.Kind() == reflect.Ptr && fv.IsNil() {

continue

}

if fv.Kind() == reflect.Slice && fv.IsNil() {

continue

}

if sep {

w.Write([]byte(", "))

} else {

sep = true

}

w.Write([]byte(v.Type().Field(i).Name))

w.Write([]byte{':'})

stringifyValue(w, fv)

}

w.Write([]byte{'}'})

default:

if v.CanInterface() {

fmt.Fprint(w, v.Interface())

}

go-stack/data/stringify.go at master · subchen/go-stack · GitHub

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