lbry.go/uint64.go
2016-09-07 21:33:21 +10:00

147 lines
3.5 KiB
Go

package null
import (
"database/sql/driver"
"encoding/json"
"fmt"
"reflect"
"strconv"
"gopkg.in/nullbio/null.v5/convert"
)
// NullUint64 is a replica of sql.NullInt64 for uint64 types.
type NullUint64 struct {
Uint64 uint64
Valid bool
}
// Uint64 is an nullable uint64.
// It does not consider zero values to be null.
// It will decode to null, not zero, if null.
type Uint64 struct {
NullUint64
}
// NewUint64 creates a new Uint64
func NewUint64(i uint64, valid bool) Uint64 {
return Uint64{
NullUint64: NullUint64{
Uint64: i,
Valid: valid,
},
}
}
// Uint64From creates a new Uint64 that will always be valid.
func Uint64From(i uint64) Uint64 {
return NewUint64(i, true)
}
// Uint64FromPtr creates a new Uint64 that be null if i is nil.
func Uint64FromPtr(i *uint64) Uint64 {
if i == nil {
return NewUint64(0, false)
}
return NewUint64(*i, true)
}
// UnmarshalJSON implements json.Unmarshaler.
// It supports number and null input.
// 0 will not be considered a null Uint64.
// It also supports unmarshalling a sql.NullUint64.
func (i *Uint64) 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 uint64, to avoid intermediate float64
err = json.Unmarshal(data, &i.Uint64)
case map[string]interface{}:
err = json.Unmarshal(data, &i.NullUint64)
case nil:
i.Valid = false
return nil
default:
err = fmt.Errorf("json: cannot unmarshal %v into Go value of type null.Uint64", reflect.TypeOf(v).Name())
}
i.Valid = err == nil
return err
}
// UnmarshalText implements encoding.TextUnmarshaler.
// It will unmarshal to a null Uint64 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 *Uint64) 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, 64)
i.Valid = err == nil
if i.Valid {
i.Uint64 = uint64(res)
}
return err
}
// MarshalJSON implements json.Marshaler.
// It will encode null if this Uint64 is null.
func (i Uint64) MarshalJSON() ([]byte, error) {
if !i.Valid {
return []byte("null"), nil
}
return []byte(strconv.FormatUint(i.Uint64, 10)), nil
}
// MarshalText implements encoding.TextMarshaler.
// It will encode a blank string if this Uint64 is null.
func (i Uint64) MarshalText() ([]byte, error) {
if !i.Valid {
return []byte{}, nil
}
return []byte(strconv.FormatUint(i.Uint64, 10)), nil
}
// SetValid changes this Uint64's value and also sets it to be non-null.
func (i *Uint64) SetValid(n uint64) {
i.Uint64 = n
i.Valid = true
}
// Ptr returns a pointer to this Uint64's value, or a nil pointer if this Uint64 is null.
func (i Uint64) Ptr() *uint64 {
if !i.Valid {
return nil
}
return &i.Uint64
}
// IsZero returns true for invalid Uint64's, for future omitempty support (Go 1.4?)
// A non-null Uint64 with a 0 value will not be considered zero.
func (i Uint64) IsZero() bool {
return !i.Valid
}
// Scan implements the Scanner interface.
func (n *NullUint64) Scan(value interface{}) error {
if value == nil {
n.Uint64, n.Valid = 0, false
return nil
}
n.Valid = true
return convert.ConvertAssign(&n.Uint64, value)
}
// Value implements the driver Valuer interface.
func (n NullUint64) Value() (driver.Value, error) {
if !n.Valid {
return nil, nil
}
return int64(n.Uint64), nil
}