81 lines
1.9 KiB
Go
81 lines
1.9 KiB
Go
package types
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import (
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"database/sql/driver"
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"encoding/json"
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"errors"
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)
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// JSONText is a json.RawMessage, which is a []byte underneath.
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// Value() validates the json format in the source, and returns an error if
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// the json is not valid. Scan does no validation. JSONText additionally
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// implements `Unmarshal`, which unmarshals the json within to an interface{}
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type JSONText json.RawMessage
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var emptyJSON = JSONText("{}")
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// MarshalJSON returns the *j as the JSON encoding of j.
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func (j JSONText) MarshalJSON() ([]byte, error) {
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if len(j) == 0 {
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return emptyJSON, nil
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}
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return j, nil
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}
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// UnmarshalJSON sets *j to a copy of data
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func (j *JSONText) UnmarshalJSON(data []byte) error {
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if j == nil {
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return errors.New("JSONText: UnmarshalJSON on nil pointer")
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}
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*j = append((*j)[0:0], data...)
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return nil
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}
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// Value returns j as a value. This does a validating unmarshal into another
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// RawMessage. If j is invalid json, it returns an error.
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func (j JSONText) Value() (driver.Value, error) {
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var m json.RawMessage
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var err = j.Unmarshal(&m)
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if err != nil {
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return []byte{}, err
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}
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return []byte(j), nil
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}
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// Scan stores the src in *j. No validation is done.
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func (j *JSONText) Scan(src interface{}) error {
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if j == nil {
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return errors.New("JSONText: Scan on nil pointer")
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}
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var source []byte
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switch t := src.(type) {
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case string:
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source = []byte(t)
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case []byte:
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if len(t) == 0 {
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source = emptyJSON
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} else {
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source = t
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}
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case nil:
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*j = emptyJSON
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default:
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return errors.New("Incompatible type for JSONText")
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}
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*j = JSONText(append((*j)[0:0], source...))
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return nil
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}
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// Unmarshal unmarshal's the json in j to v, as in json.Unmarshal.
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func (j *JSONText) Unmarshal(v interface{}) error {
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if len(*j) == 0 {
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*j = emptyJSON
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}
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return json.Unmarshal([]byte(*j), v)
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}
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// String supports pretty printing for JSONText types.
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func (j JSONText) String() string {
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return string(j)
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}
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