lbry.go/int.go
2016-09-07 21:33:21 +10:00

148 lines
3.3 KiB
Go

package null
import (
"database/sql/driver"
"encoding/json"
"fmt"
"reflect"
"strconv"
"gopkg.in/nullbio/null.v5/convert"
)
// NullInt is a replica of sql.NullInt64 for int types.
type NullInt struct {
Int int
Valid bool
}
// Int is an nullable int.
// It does not consider zero values to be null.
// It will decode to null, not zero, if null.
type Int struct {
NullInt
}
// NewInt creates a new Int
func NewInt(i int, valid bool) Int {
return Int{
NullInt: NullInt{
Int: i,
Valid: valid,
},
}
}
// IntFrom creates a new Int that will always be valid.
func IntFrom(i int) Int {
return NewInt(i, true)
}
// IntFromPtr creates a new Int that be null if i is nil.
func IntFromPtr(i *int) Int {
if i == nil {
return NewInt(0, false)
}
return NewInt(*i, true)
}
// UnmarshalJSON implements json.Unmarshaler.
// It supports number and null input.
// 0 will not be considered a null Int.
// It also supports unmarshalling a sql.NullInt.
func (i *Int) UnmarshalJSON(data []byte) error {
var err error
var v interface{}
if err = json.Unmarshal(data, &v); err != nil {
return err
}
switch v.(type) {
case float64:
// Unmarshal again, directly to int, to avoid intermediate float64
err = json.Unmarshal(data, &i.Int)
case map[string]interface{}:
err = json.Unmarshal(data, &i.NullInt)
case nil:
i.Valid = false
return nil
default:
err = fmt.Errorf("json: cannot unmarshal %v into Go value of type null.Int", reflect.TypeOf(v).Name())
}
i.Valid = err == nil
return err
}
// UnmarshalText implements encoding.TextUnmarshaler.
// It will unmarshal to a null Int if the input is a blank or not an integer.
// It will return an error if the input is not an integer, blank, or "null".
func (i *Int) UnmarshalText(text []byte) error {
str := string(text)
if str == "" || str == "null" {
i.Valid = false
return nil
}
var err error
res, err := strconv.ParseInt(string(text), 10, 0)
i.Valid = err == nil
if i.Valid {
i.Int = int(res)
}
return err
}
// MarshalJSON implements json.Marshaler.
// It will encode null if this Int is null.
func (i Int) MarshalJSON() ([]byte, error) {
if !i.Valid {
return []byte("null"), nil
}
return []byte(strconv.FormatInt(int64(i.Int), 10)), nil
}
// MarshalText implements encoding.TextMarshaler.
// It will encode a blank string if this Int is null.
func (i Int) MarshalText() ([]byte, error) {
if !i.Valid {
return []byte{}, nil
}
return []byte(strconv.FormatInt(int64(i.Int), 10)), nil
}
// SetValid changes this Int's value and also sets it to be non-null.
func (i *Int) SetValid(n int) {
i.Int = n
i.Valid = true
}
// Ptr returns a pointer to this Int's value, or a nil pointer if this Int is null.
func (i Int) Ptr() *int {
if !i.Valid {
return nil
}
return &i.Int
}
// IsZero returns true for invalid Ints, for future omitempty support (Go 1.4?)
// A non-null Int with a 0 value will not be considered zero.
func (i Int) IsZero() bool {
return !i.Valid
}
// Scan implements the Scanner interface.
func (n *NullInt) Scan(value interface{}) error {
if value == nil {
n.Int, n.Valid = 0, false
return nil
}
n.Valid = true
return convert.ConvertAssign(&n.Int, value)
}
// Value implements the driver Valuer interface.
func (n NullInt) Value() (driver.Value, error) {
if !n.Valid {
return nil, nil
}
return int64(n.Int), nil
}