forked from guregu/null
/
int32.go
145 lines (129 loc) · 3.52 KB
/
int32.go
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package null
import (
"bytes"
"database/sql"
"encoding/json"
"errors"
"fmt"
"strconv"
)
// 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 {
sql.NullInt32
}
// NewInt32 creates a new Int32
func NewInt32(i int32, valid bool) Int32 {
return Int32{
NullInt32: sql.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)
}
// ValueOrZero returns the inner value if valid, otherwise zero.
func (i Int32) ValueOrZero() int32 {
if !i.Valid {
return 0
}
return i.Int32
}
// UnmarshalJSON implements json.Unmarshaler.
// It supports number, string, and null input.
// 0 will not be considered a null Int32.
func (i *Int32) UnmarshalJSON(data []byte) error {
if bytes.Equal(data, nullBytes) {
i.Valid = false
return nil
}
if err := json.Unmarshal(data, &i.Int32); err != nil {
var typeError *json.UnmarshalTypeError
if errors.As(err, &typeError) {
// special case: accept string input
if typeError.Value != "string" {
return fmt.Errorf("null: JSON input is invalid type (need int32 or string): %w", err)
}
var str string
if err := json.Unmarshal(data, &str); err != nil {
return fmt.Errorf("null: couldn't unmarshal number string: %w", err)
}
n, err := strconv.ParseInt(str, 10, 64)
if err != nil {
return fmt.Errorf("null: couldn't convert string to int32: %w", err)
}
i.Int32 = int32(n)
i.Valid = true
return nil
}
return fmt.Errorf("null: couldn't unmarshal JSON: %w", err)
}
i.Valid = true
return nil
}
// UnmarshalText implements encoding.TextUnmarshaler.
// It will unmarshal to a null Int32 if the input is blank.
// 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
parsedInt, err := strconv.ParseInt(string(text), 10, 64)
i.Int32 = int32(parsedInt)
if err != nil {
return fmt.Errorf("null: couldn't unmarshal text: %w", err)
}
i.Valid = true
return nil
}
// 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 Int32s, 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
}
// Equal returns true if both int32s have the same value or are both null.
func (i Int32) Equal(other Int32) bool {
return i.Valid == other.Valid && (!i.Valid || i.Int32 == other.Int32)
}