vendor/github.com/hashicorp/terraform/flatmap/flatten.go

   1 package flatmap
   2
   3 import (
   4         "fmt"
   5         "reflect"
   6 )
   7
   8 // Flatten takes a structure and turns into a flat map[string]string.
   9 //
  10 // Within the "thing" parameter, only primitive values are allowed. Structs are
  11 // not supported. Therefore, it can only be slices, maps, primitives, and
  12 // any combination of those together.
  13 //
  14 // See the tests for examples of what inputs are turned into.
  15 func Flatten(thing map[string]interface{}) Map {
  16         result := make(map[string]string)
  17
  18         for k, raw := range thing {
  19                 flatten(result, k, reflect.ValueOf(raw))
  20         }
  21
  22         return Map(result)
  23 }
  24
  25 func flatten(result map[string]string, prefix string, v reflect.Value) {
  26         if v.Kind() == reflect.Interface {
  27                 v = v.Elem()
  28         }
  29
  30         switch v.Kind() {
  31         case reflect.Bool:
  32                 if v.Bool() {
  33                         result[prefix] = "true"
  34                 } else {
  35                         result[prefix] = "false"
  36                 }
  37         case reflect.Int:
  38                 result[prefix] = fmt.Sprintf("%d", v.Int())
  39         case reflect.Map:
  40                 flattenMap(result, prefix, v)
  41         case reflect.Slice:
  42                 flattenSlice(result, prefix, v)
  43         case reflect.String:
  44                 result[prefix] = v.String()
  45         default:
  46                 panic(fmt.Sprintf("Unknown: %s", v))
  47         }
  48 }
  49
  50 func flattenMap(result map[string]string, prefix string, v reflect.Value) {
  51         for _, k := range v.MapKeys() {
  52                 if k.Kind() == reflect.Interface {
  53                         k = k.Elem()
  54                 }
  55
  56                 if k.Kind() != reflect.String {
  57                         panic(fmt.Sprintf("%s: map key is not string: %s", prefix, k))
  58                 }
  59
  60                 flatten(result, fmt.Sprintf("%s.%s", prefix, k.String()), v.MapIndex(k))
  61         }
  62 }
  63
  64 func flattenSlice(result map[string]string, prefix string, v reflect.Value) {
  65         prefix = prefix + "."
  66
  67         result[prefix+"#"] = fmt.Sprintf("%d", v.Len())
  68         for i := 0; i < v.Len(); i++ {
  69                 flatten(result, fmt.Sprintf("%s%d", prefix, i), v.Index(i))
  70         }
  71 }