int64.go

package nulls

import (
	"database/sql"
	"database/sql/driver"
	"encoding/json"
	"strconv"
)

// Int64 replaces sql.Int64 with an implementation
// that supports proper JSON encoding/decoding.
type Int64 sql.NullInt64

// NewInt64 returns a new, properly instantiated
// Int64 object.
func NewInt64(i int64) Int64 {
	return Int64{Int64: i, Valid: true}
}

// Scan implements the Scanner interface.
func (ns *Int64) Scan(value interface{}) error {
	n := sql.NullInt64{Int64: ns.Int64}
	err := n.Scan(value)
	ns.Int64, ns.Valid = n.Int64, n.Valid
	return err
}

// Value implements the driver Valuer interface.
func (ns Int64) Value() (driver.Value, error) {
	if !ns.Valid {
		return nil, nil
	}
	return ns.Int64, nil
}

// MarshalJSON marshals the underlying value to a
// proper JSON representation.
func (ns Int64) MarshalJSON() ([]byte, error) {
	if ns.Valid {
		return json.Marshal(ns.Int64)
	}
	return json.Marshal(nil)
}

// UnmarshalJSON will unmarshal a JSON value into
// the propert representation of that value.
func (ns *Int64) UnmarshalJSON(text []byte) error {
	t := string(text)
	ns.Valid = true
	if t == "null" {
		ns.Valid = false
		return nil
	}
	i, err := strconv.ParseInt(t, 10, 64)
	if err != nil {
		ns.Valid = false
		return err
	}
	ns.Int64 = i
	return nil
}