lbry.go/uint.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"
)
// NullUint is a replica of sql.NullInt64 for uint types.
type NullUint struct {
Uint uint
Valid bool
}
// Uint is an nullable uint.
// It does not consider zero values to be null.
// It will decode to null, not zero, if null.
type Uint struct {
NullUint
}
// NewUint creates a new Uint
func NewUint(i uint, valid bool) Uint {
return Uint{
NullUint: NullUint{
Uint: i,
Valid: valid,
},
}
}
// UintFrom creates a new Uint that will always be valid.
func UintFrom(i uint) Uint {
return NewUint(i, true)
}
// UintFromPtr creates a new Uint that be null if i is nil.
func UintFromPtr(i *uint) Uint {
if i == nil {
return NewUint(0, false)
}
return NewUint(*i, true)
}
// UnmarshalJSON implements json.Unmarshaler.
// It supports number and null input.
// 0 will not be considered a null Uint.
// It also supports unmarshalling a sql.NullUint.
func (i *Uint) 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 uint, to avoid intermediate float64
err = json.Unmarshal(data, &i.Uint)
case map[string]interface{}:
err = json.Unmarshal(data, &i.NullUint)
case nil:
i.Valid = false
return nil
default:
err = fmt.Errorf("json: cannot unmarshal %v into Go value of type null.Uint", reflect.TypeOf(v).Name())
}
i.Valid = err == nil
return err
}
// UnmarshalText implements encoding.TextUnmarshaler.
// It will unmarshal to a null Uint 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 *Uint) UnmarshalText(text []byte) error {
str := string(text)
if str == "" || str == "null" {
i.Valid = false
return nil
}
var err error
res, err := strconv.ParseUint(string(text), 10, 0)
i.Valid = err == nil
if i.Valid {
i.Uint = uint(res)
}
return err
}
// MarshalJSON implements json.Marshaler.
// It will encode null if this Uint is null.
func (i Uint) MarshalJSON() ([]byte, error) {
if !i.Valid {
return []byte("null"), nil
}
return []byte(strconv.FormatUint(uint64(i.Uint), 10)), nil
}
// MarshalText implements encoding.TextMarshaler.
// It will encode a blank string if this Uint is null.
func (i Uint) MarshalText() ([]byte, error) {
if !i.Valid {
return []byte{}, nil
}
return []byte(strconv.FormatUint(uint64(i.Uint), 10)), nil
}
// SetValid changes this Uint's value and also sets it to be non-null.
func (i *Uint) SetValid(n uint) {
i.Uint = n
i.Valid = true
}
// Ptr returns a pointer to this Uint's value, or a nil pointer if this Uint is null.
func (i Uint) Ptr() *uint {
if !i.Valid {
return nil
}
return &i.Uint
}
// IsZero returns true for invalid Uints, for future omitempty support (Go 1.4?)
// A non-null Uint with a 0 value will not be considered zero.
func (i Uint) IsZero() bool {
return !i.Valid
}
// Scan implements the Scanner interface.
func (n *NullUint) Scan(value interface{}) error {
if value == nil {
n.Uint, n.Valid = 0, false
return nil
}
n.Valid = true
return convert.ConvertAssign(&n.Uint, value)
}
// Value implements the driver Valuer interface.
func (n NullUint) Value() (driver.Value, error) {
if !n.Valid {
return nil, nil
}
return int64(n.Uint), nil
}