lbry.go/int32.go
Patrick O'brien 67ba4e0272 Fix README, fix Valuer methods
* Fix import paths
2016-06-08 13:53:02 +10:00

147 lines
3.4 KiB
Go

package null
import (
"database/sql/driver"
"encoding/json"
"fmt"
"reflect"
"strconv"
"gopkg.in/nullbio/null.v4/convert"
)
// NullInt32 is a replica of sql.NullInt64 for int32 types.
type NullInt32 struct {
Int32 int32
Valid bool
}
// Int32 is an nullable int32.
// It does not consider zero values to be null.
// It will decode to null, not zero, if null.
type Int32 struct {
NullInt32
}
// NewInt32 creates a new Int32
func NewInt32(i int32, valid bool) Int32 {
return Int32{
NullInt32: NullInt32{
Int32: i,
Valid: valid,
},
}
}
// Int32From creates a new Int32 that will always be valid.
func Int32From(i int32) Int32 {
return NewInt32(i, true)
}
// Int32FromPtr creates a new Int32 that be null if i is nil.
func Int32FromPtr(i *int32) Int32 {
if i == nil {
return NewInt32(0, false)
}
return NewInt32(*i, true)
}
// UnmarshalJSON implements json.Unmarshaler.
// It supports number and null input.
// 0 will not be considered a null Int32.
// It also supports unmarshalling a sql.NullInt32.
func (i *Int32) 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 int32, to avoid intermediate float64
err = json.Unmarshal(data, &i.Int32)
case map[string]interface{}:
err = json.Unmarshal(data, &i.NullInt32)
case nil:
i.Valid = false
return nil
default:
err = fmt.Errorf("json: cannot unmarshal %v into Go value of type null.Int32", reflect.TypeOf(v).Name())
}
i.Valid = err == nil
return err
}
// UnmarshalText implements encoding.TextUnmarshaler.
// It will unmarshal to a null Int32 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 *Int32) 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, 32)
i.Valid = err == nil
if i.Valid {
i.Int32 = int32(res)
}
return err
}
// MarshalJSON implements json.Marshaler.
// It will encode null if this Int32 is null.
func (i Int32) MarshalJSON() ([]byte, error) {
if !i.Valid {
return []byte("null"), nil
}
return []byte(strconv.FormatInt(int64(i.Int32), 10)), nil
}
// MarshalText implements encoding.TextMarshaler.
// It will encode a blank string if this Int32 is null.
func (i Int32) MarshalText() ([]byte, error) {
if !i.Valid {
return []byte{}, nil
}
return []byte(strconv.FormatInt(int64(i.Int32), 10)), nil
}
// SetValid changes this Int32's value and also sets it to be non-null.
func (i *Int32) SetValid(n int32) {
i.Int32 = n
i.Valid = true
}
// Ptr returns a pointer to this Int32's value, or a nil pointer if this Int32 is null.
func (i Int32) Ptr() *int32 {
if !i.Valid {
return nil
}
return &i.Int32
}
// IsZero returns true for invalid Int32's, for future omitempty support (Go 1.4?)
// A non-null Int32 with a 0 value will not be considered zero.
func (i Int32) IsZero() bool {
return !i.Valid
}
// Scan implements the Scanner interface.
func (n *NullInt32) Scan(value interface{}) error {
if value == nil {
n.Int32, n.Valid = 0, false
return nil
}
n.Valid = true
return convert.ConvertAssign(&n.Int32, value)
}
// Value implements the driver Valuer interface.
func (n NullInt32) Value() (driver.Value, error) {
if !n.Valid {
return nil, nil
}
return int64(n.Int32), nil
}