49 lines
1.0 KiB
Go
49 lines
1.0 KiB
Go
package nul
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import (
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"encoding/json"
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"reflect"
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"github.com/reiver/go-erorr"
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)
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const errNilReceiver = erorr.Error("nul: nil receiver")
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var _ json.Unmarshaler = new(Nullable[bool])
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var _ json.Unmarshaler = new(Nullable[string])
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// UnmarshalJSON makes it so json.Unmarshaler is implemented.
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func (receiver *Nullable[T]) UnmarshalJSON(data []byte) error {
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if nil == receiver {
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return errNilReceiver
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}
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switch interface{}(receiver.value).(type) {
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case bool,string,json.Unmarshaler:
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// these are OK.
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default:
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if reflect.Struct != reflect.TypeOf(receiver.value).Kind() {
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return erorr.Errorf("nul: cannot unmarshal into something of type %T from JSON because parameterized type is ‘%T’ rather than ‘bool’, ‘string’, or ‘json.Unmarshaler’", receiver, receiver.value)
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}
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}
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if 4 == len(data) && 'n' == data[0] && 'u' == data[1] && 'l' == data[2] && 'l' == data[3] {
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*receiver = Null[T]()
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return nil
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}
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{
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var dst T
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err := json.Unmarshal(data, &dst)
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if nil != err {
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return err
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}
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*receiver = Something(dst)
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}
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return nil
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}
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