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| 1 | +package mapstructure |
| 2 | + |
| 3 | +import ( |
| 4 | + "errors" |
| 5 | + "reflect" |
| 6 | + "strconv" |
| 7 | + "strings" |
| 8 | + "time" |
| 9 | +) |
| 10 | + |
| 11 | +// typedDecodeHook takes a raw DecodeHookFunc (an interface{}) and turns |
| 12 | +// it into the proper DecodeHookFunc type, such as DecodeHookFuncType. |
| 13 | +func typedDecodeHook(h DecodeHookFunc) DecodeHookFunc { |
| 14 | + // Create variables here so we can reference them with the reflect pkg |
| 15 | + var f1 DecodeHookFuncType |
| 16 | + var f2 DecodeHookFuncKind |
| 17 | + |
| 18 | + // Fill in the variables into this interface and the rest is done |
| 19 | + // automatically using the reflect package. |
| 20 | + potential := []interface{}{f1, f2} |
| 21 | + |
| 22 | + v := reflect.ValueOf(h) |
| 23 | + vt := v.Type() |
| 24 | + for _, raw := range potential { |
| 25 | + pt := reflect.ValueOf(raw).Type() |
| 26 | + if vt.ConvertibleTo(pt) { |
| 27 | + return v.Convert(pt).Interface() |
| 28 | + } |
| 29 | + } |
| 30 | + |
| 31 | + return nil |
| 32 | +} |
| 33 | + |
| 34 | +// DecodeHookExec executes the given decode hook. This should be used |
| 35 | +// since it'll naturally degrade to the older backwards compatible DecodeHookFunc |
| 36 | +// that took reflect.Kind instead of reflect.Type. |
| 37 | +func DecodeHookExec( |
| 38 | + raw DecodeHookFunc, |
| 39 | + from reflect.Type, to reflect.Type, |
| 40 | + data interface{}) (interface{}, error) { |
| 41 | + switch f := typedDecodeHook(raw).(type) { |
| 42 | + case DecodeHookFuncType: |
| 43 | + return f(from, to, data) |
| 44 | + case DecodeHookFuncKind: |
| 45 | + return f(from.Kind(), to.Kind(), data) |
| 46 | + default: |
| 47 | + return nil, errors.New("invalid decode hook signature") |
| 48 | + } |
| 49 | +} |
| 50 | + |
| 51 | +// ComposeDecodeHookFunc creates a single DecodeHookFunc that |
| 52 | +// automatically composes multiple DecodeHookFuncs. |
| 53 | +// |
| 54 | +// The composed funcs are called in order, with the result of the |
| 55 | +// previous transformation. |
| 56 | +func ComposeDecodeHookFunc(fs ...DecodeHookFunc) DecodeHookFunc { |
| 57 | + return func( |
| 58 | + f reflect.Type, |
| 59 | + t reflect.Type, |
| 60 | + data interface{}) (interface{}, error) { |
| 61 | + var err error |
| 62 | + for _, f1 := range fs { |
| 63 | + data, err = DecodeHookExec(f1, f, t, data) |
| 64 | + if err != nil { |
| 65 | + return nil, err |
| 66 | + } |
| 67 | + |
| 68 | + // Modify the from kind to be correct with the new data |
| 69 | + f = nil |
| 70 | + if val := reflect.ValueOf(data); val.IsValid() { |
| 71 | + f = val.Type() |
| 72 | + } |
| 73 | + } |
| 74 | + |
| 75 | + return data, nil |
| 76 | + } |
| 77 | +} |
| 78 | + |
| 79 | +// StringToSliceHookFunc returns a DecodeHookFunc that converts |
| 80 | +// string to []string by splitting on the given sep. |
| 81 | +func StringToSliceHookFunc(sep string) DecodeHookFunc { |
| 82 | + return func( |
| 83 | + f reflect.Kind, |
| 84 | + t reflect.Kind, |
| 85 | + data interface{}) (interface{}, error) { |
| 86 | + if f != reflect.String || t != reflect.Slice { |
| 87 | + return data, nil |
| 88 | + } |
| 89 | + |
| 90 | + raw := data.(string) |
| 91 | + if raw == "" { |
| 92 | + return []string{}, nil |
| 93 | + } |
| 94 | + |
| 95 | + return strings.Split(raw, sep), nil |
| 96 | + } |
| 97 | +} |
| 98 | + |
| 99 | +// StringToTimeDurationHookFunc returns a DecodeHookFunc that converts |
| 100 | +// strings to time.Duration. |
| 101 | +func StringToTimeDurationHookFunc() DecodeHookFunc { |
| 102 | + return func( |
| 103 | + f reflect.Type, |
| 104 | + t reflect.Type, |
| 105 | + data interface{}) (interface{}, error) { |
| 106 | + if f.Kind() != reflect.String { |
| 107 | + return data, nil |
| 108 | + } |
| 109 | + if t != reflect.TypeOf(time.Duration(5)) { |
| 110 | + return data, nil |
| 111 | + } |
| 112 | + |
| 113 | + // Convert it by parsing |
| 114 | + return time.ParseDuration(data.(string)) |
| 115 | + } |
| 116 | +} |
| 117 | + |
| 118 | +// StringToTimeHookFunc returns a DecodeHookFunc that converts |
| 119 | +// strings to time.Time. |
| 120 | +func StringToTimeHookFunc(layout string) DecodeHookFunc { |
| 121 | + return func( |
| 122 | + f reflect.Type, |
| 123 | + t reflect.Type, |
| 124 | + data interface{}) (interface{}, error) { |
| 125 | + if f.Kind() != reflect.String { |
| 126 | + return data, nil |
| 127 | + } |
| 128 | + if t != reflect.TypeOf(time.Time{}) { |
| 129 | + return data, nil |
| 130 | + } |
| 131 | + |
| 132 | + // Convert it by parsing |
| 133 | + return time.Parse(layout, data.(string)) |
| 134 | + } |
| 135 | +} |
| 136 | + |
| 137 | +// WeaklyTypedHook is a DecodeHookFunc which adds support for weak typing to |
| 138 | +// the decoder. |
| 139 | +// |
| 140 | +// Note that this is significantly different from the WeaklyTypedInput option |
| 141 | +// of the DecoderConfig. |
| 142 | +func WeaklyTypedHook( |
| 143 | + f reflect.Kind, |
| 144 | + t reflect.Kind, |
| 145 | + data interface{}) (interface{}, error) { |
| 146 | + dataVal := reflect.ValueOf(data) |
| 147 | + switch t { |
| 148 | + case reflect.String: |
| 149 | + switch f { |
| 150 | + case reflect.Bool: |
| 151 | + if dataVal.Bool() { |
| 152 | + return "1", nil |
| 153 | + } |
| 154 | + return "0", nil |
| 155 | + case reflect.Float32: |
| 156 | + return strconv.FormatFloat(dataVal.Float(), 'f', -1, 64), nil |
| 157 | + case reflect.Int: |
| 158 | + return strconv.FormatInt(dataVal.Int(), 10), nil |
| 159 | + case reflect.Slice: |
| 160 | + dataType := dataVal.Type() |
| 161 | + elemKind := dataType.Elem().Kind() |
| 162 | + if elemKind == reflect.Uint8 { |
| 163 | + return string(dataVal.Interface().([]uint8)), nil |
| 164 | + } |
| 165 | + case reflect.Uint: |
| 166 | + return strconv.FormatUint(dataVal.Uint(), 10), nil |
| 167 | + } |
| 168 | + } |
| 169 | + |
| 170 | + return data, nil |
| 171 | +} |
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