157 lines
3.2 KiB
Go
157 lines
3.2 KiB
Go
package null
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import (
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"bytes"
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"database/sql/driver"
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"encoding/json"
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"errors"
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"fmt"
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"gopkg.in/nullbio/null.v6/convert"
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)
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// JSON is a nullable []byte.
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type JSON struct {
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JSON []byte
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Valid bool
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}
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// NewJSON creates a new JSON
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func NewJSON(b []byte, valid bool) JSON {
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return JSON{
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JSON: b,
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Valid: valid,
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}
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}
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// JSONFrom creates a new JSON that will be invalid if nil.
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func JSONFrom(b []byte) JSON {
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return NewJSON(b, b != nil)
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}
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// JSONFromPtr creates a new JSON that will be invalid if nil.
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func JSONFromPtr(b *[]byte) JSON {
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if b == nil {
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return NewJSON(nil, false)
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}
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n := NewJSON(*b, true)
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return n
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}
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// Unmarshal will unmarshal your JSON stored in
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// your JSON object and store the result in the
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// value pointed to by dest.
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func (j JSON) Unmarshal(dest interface{}) error {
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if dest == nil {
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return errors.New("destination is nil, not a valid pointer to an object")
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}
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// Call our implementation of
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// JSON MarshalJSON through json.Marshal
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// to get the value of the JSON object
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res, err := json.Marshal(j)
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if err != nil {
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return err
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}
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return json.Unmarshal(res, dest)
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}
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// UnmarshalJSON implements json.Unmarshaler.
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func (j *JSON) UnmarshalJSON(data []byte) error {
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if data == nil {
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return fmt.Errorf("json: cannot unmarshal nil into Go value of type null.JSON")
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}
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if bytes.Equal(data, NullBytes) {
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j.JSON = NullBytes
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j.Valid = false
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return nil
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}
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j.Valid = true
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j.JSON = make([]byte, len(data))
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copy(j.JSON, data)
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return nil
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}
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// UnmarshalText implements encoding.TextUnmarshaler.
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func (j *JSON) UnmarshalText(text []byte) error {
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if text == nil || len(text) == 0 {
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j.JSON = nil
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j.Valid = false
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} else {
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j.JSON = append(j.JSON[0:0], text...)
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j.Valid = true
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}
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return nil
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}
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// Marshal will marshal the passed in object,
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// and store it in the JSON member on the JSON object.
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func (j *JSON) Marshal(obj interface{}) error {
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res, err := json.Marshal(obj)
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if err != nil {
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return err
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}
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// Call our implementation of
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// JSON UnmarshalJSON through json.Unmarshal
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// to set the result to the JSON object
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return json.Unmarshal(res, j)
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}
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// MarshalJSON implements json.Marshaler.
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func (j JSON) MarshalJSON() ([]byte, error) {
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if len(j.JSON) == 0 || j.JSON == nil {
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return NullBytes, nil
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}
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return j.JSON, nil
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}
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// MarshalText implements encoding.TextMarshaler.
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func (j JSON) MarshalText() ([]byte, error) {
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if !j.Valid {
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return nil, nil
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}
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return j.JSON, nil
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}
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// SetValid changes this JSON's value and also sets it to be non-null.
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func (j *JSON) SetValid(n []byte) {
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j.JSON = n
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j.Valid = true
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}
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// Ptr returns a pointer to this JSON's value, or a nil pointer if this JSON is null.
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func (j JSON) Ptr() *[]byte {
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if !j.Valid {
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return nil
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}
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return &j.JSON
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}
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// IsNull returns true for null or zero JSON's, for future omitempty support (Go 1.4?)
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func (j JSON) IsNull() bool {
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return !j.Valid
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}
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// Scan implements the Scanner interface.
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func (j *JSON) Scan(value interface{}) error {
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if value == nil {
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j.JSON, j.Valid = []byte{}, false
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return nil
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}
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j.Valid = true
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return convert.ConvertAssign(&j.JSON, value)
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}
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// Value implements the driver Valuer interface.
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func (j JSON) Value() (driver.Value, error) {
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if !j.Valid {
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return nil, nil
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}
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return j.JSON, nil
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}
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