vendor/github.com/hashicorp/terraform/helper/hilmapstructure/hilmapstructure.go

   1 package hilmapstructure
   2
   3 import (
   4         "fmt"
   5         "reflect"
   6
   7         "github.com/mitchellh/mapstructure"
   8 )
   9
  10 var hilMapstructureDecodeHookEmptySlice []interface{}
  11 var hilMapstructureDecodeHookStringSlice []string
  12 var hilMapstructureDecodeHookEmptyMap map[string]interface{}
  13
  14 // WeakDecode behaves in the same way as mapstructure.WeakDecode but has a
  15 // DecodeHook which defeats the backward compatibility mode of mapstructure
  16 // which WeakDecodes []interface{}{} into an empty map[string]interface{}. This
  17 // allows us to use WeakDecode (desirable), but not fail on empty lists.
  18 func WeakDecode(m interface{}, rawVal interface{}) error {
  19         config := &mapstructure.DecoderConfig{
  20                 DecodeHook: func(source reflect.Type, target reflect.Type, val interface{}) (interface{}, error) {
  21                         sliceType := reflect.TypeOf(hilMapstructureDecodeHookEmptySlice)
  22                         stringSliceType := reflect.TypeOf(hilMapstructureDecodeHookStringSlice)
  23                         mapType := reflect.TypeOf(hilMapstructureDecodeHookEmptyMap)
  24
  25                         if (source == sliceType || source == stringSliceType) && target == mapType {
  26                                 return nil, fmt.Errorf("Cannot convert a []interface{} into a map[string]interface{}")
  27                         }
  28
  29                         return val, nil
  30                 },
  31                 WeaklyTypedInput: true,
  32                 Result:           rawVal,
  33         }
  34
  35         decoder, err := mapstructure.NewDecoder(config)
  36         if err != nil {
  37                 return err
  38         }
  39
  40         return decoder.Decode(m)
  41 }