vendor/github.com/aws/aws-sdk-go/aws/awsutil/prettify.go

   1 package awsutil
   2
   3 import (
   4         "bytes"
   5         "fmt"
   6         "io"
   7         "reflect"
   8         "strings"
   9 )
  10
  11 // Prettify returns the string representation of a value.
  12 func Prettify(i interface{}) string {
  13         var buf bytes.Buffer
  14         prettify(reflect.ValueOf(i), 0, &buf)
  15         return buf.String()
  16 }
  17
  18 // prettify will recursively walk value v to build a textual
  19 // representation of the value.
  20 func prettify(v reflect.Value, indent int, buf *bytes.Buffer) {
  21         for v.Kind() == reflect.Ptr {
  22                 v = v.Elem()
  23         }
  24
  25         switch v.Kind() {
  26         case reflect.Struct:
  27                 strtype := v.Type().String()
  28                 if strtype == "time.Time" {
  29                         fmt.Fprintf(buf, "%s", v.Interface())
  30                         break
  31                 } else if strings.HasPrefix(strtype, "io.") {
  32                         buf.WriteString("<buffer>")
  33                         break
  34                 }
  35
  36                 buf.WriteString("{\n")
  37
  38                 names := []string{}
  39                 for i := 0; i < v.Type().NumField(); i++ {
  40                         name := v.Type().Field(i).Name
  41                         f := v.Field(i)
  42                         if name[0:1] == strings.ToLower(name[0:1]) {
  43                                 continue // ignore unexported fields
  44                         }
  45                         if (f.Kind() == reflect.Ptr || f.Kind() == reflect.Slice || f.Kind() == reflect.Map) && f.IsNil() {
  46                                 continue // ignore unset fields
  47                         }
  48                         names = append(names, name)
  49                 }
  50
  51                 for i, n := range names {
  52                         val := v.FieldByName(n)
  53                         buf.WriteString(strings.Repeat(" ", indent+2))
  54                         buf.WriteString(n + ": ")
  55                         prettify(val, indent+2, buf)
  56
  57                         if i < len(names)-1 {
  58                                 buf.WriteString(",\n")
  59                         }
  60                 }
  61
  62                 buf.WriteString("\n" + strings.Repeat(" ", indent) + "}")
  63         case reflect.Slice:
  64                 strtype := v.Type().String()
  65                 if strtype == "[]uint8" {
  66                         fmt.Fprintf(buf, "<binary> len %d", v.Len())
  67                         break
  68                 }
  69
  70                 nl, id, id2 := "", "", ""
  71                 if v.Len() > 3 {
  72                         nl, id, id2 = "\n", strings.Repeat(" ", indent), strings.Repeat(" ", indent+2)
  73                 }
  74                 buf.WriteString("[" + nl)
  75                 for i := 0; i < v.Len(); i++ {
  76                         buf.WriteString(id2)
  77                         prettify(v.Index(i), indent+2, buf)
  78
  79                         if i < v.Len()-1 {
  80                                 buf.WriteString("," + nl)
  81                         }
  82                 }
  83
  84                 buf.WriteString(nl + id + "]")
  85         case reflect.Map:
  86                 buf.WriteString("{\n")
  87
  88                 for i, k := range v.MapKeys() {
  89                         buf.WriteString(strings.Repeat(" ", indent+2))
  90                         buf.WriteString(k.String() + ": ")
  91                         prettify(v.MapIndex(k), indent+2, buf)
  92
  93                         if i < v.Len()-1 {
  94                                 buf.WriteString(",\n")
  95                         }
  96                 }
  97
  98                 buf.WriteString("\n" + strings.Repeat(" ", indent) + "}")
  99         default:
 100                 if !v.IsValid() {
 101                         fmt.Fprint(buf, "<invalid value>")
 102                         return
 103                 }
 104                 format := "%v"
 105                 switch v.Interface().(type) {
 106                 case string:
 107                         format = "%q"
 108                 case io.ReadSeeker, io.Reader:
 109                         format = "buffer(%p)"
 110                 }
 111                 fmt.Fprintf(buf, format, v.Interface())
 112         }
 113 }