Add json/jsonb to pgtype

pgtype/json.go

@@ -0,0 +1,102 @@
+package pgtype
+
+import (
+	"encoding/json"
+	"io"
+)
+
+type Json struct {
+	Bytes  []byte
+	Status Status
+}
+
+func (dst *Json) ConvertFrom(src interface{}) error {
+	switch value := src.(type) {
+	case string:
+		*dst = Json{Bytes: []byte(value), Status: Present}
+	case *string:
+		if value == nil {
+			*dst = Json{Status: Null}
+		} else {
+			*dst = Json{Bytes: []byte(*value), Status: Present}
+		}
+	case []byte:
+		if value == nil {
+			*dst = Json{Status: Null}
+		} else {
+			*dst = Json{Bytes: value, Status: Present}
+		}
+	default:
+		buf, err := json.Marshal(value)
+		if err != nil {
+			return err
+		}
+		*dst = Json{Bytes: buf, Status: Present}
+	}
+
+	return nil
+}
+
+func (src *Json) AssignTo(dst interface{}) error {
+	switch v := dst.(type) {
+	case *string:
+		if src.Status != Present {
+			v = nil
+		} else {
+			*v = string(src.Bytes)
+		}
+	case **string:
+		*v = new(string)
+		return src.AssignTo(*v)
+	case *[]byte:
+		if src.Status != Present {
+			*v = nil
+		} else {
+			buf := make([]byte, len(src.Bytes))
+			copy(buf, src.Bytes)
+			*v = buf
+		}
+	default:
+		data := src.Bytes
+		if data == nil || src.Status != Present {
+			data = []byte("null")
+		}
+
+		return json.Unmarshal(data, dst)
+	}
+
+	return nil
+}
+
+func (dst *Json) DecodeText(src []byte) error {
+	if src == nil {
+		*dst = Json{Status: Null}
+		return nil
+	}
+
+	buf := make([]byte, len(src))
+	copy(buf, src)
+
+	*dst = Json{Bytes: buf, Status: Present}
+	return nil
+}
+
+func (dst *Json) DecodeBinary(src []byte) error {
+	return dst.DecodeText(src)
+}
+
+func (src Json) EncodeText(w io.Writer) (bool, error) {
+	switch src.Status {
+	case Null:
+		return true, nil
+	case Undefined:
+		return false, errUndefined
+	}
+
+	_, err := w.Write(src.Bytes)
+	return false, err
+}
+
+func (src Json) EncodeBinary(w io.Writer) (bool, error) {
+	return src.EncodeText(w)
+}