forked from guregu/null
/
int.go
146 lines (130 loc) · 3.31 KB
/
int.go
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package zero
import (
"bytes"
"database/sql"
"encoding/json"
"errors"
"fmt"
"strconv"
)
// Int is a nullable int64.
// JSON marshals to zero if null.
// Considered null to SQL if zero.
type Int struct {
sql.NullInt64
}
// NewInt creates a new Int
func NewInt(i int64, valid bool) Int {
return Int{
NullInt64: sql.NullInt64{
Int64: i,
Valid: valid,
},
}
}
// IntFrom creates a new Int that will be null if zero.
func IntFrom(i int64) Int {
return NewInt(i, i != 0)
}
// IntFromPtr creates a new Int that be null if i is nil.
func IntFromPtr(i *int64) Int {
if i == nil {
return NewInt(0, false)
}
n := NewInt(*i, true)
return n
}
// ValueOrZero returns the inner value if valid, otherwise zero.
func (i Int) ValueOrZero() int64 {
if !i.Valid {
return 0
}
return i.Int64
}
// UnmarshalJSON implements json.Unmarshaler.
// It supports number and null input.
// 0 will be considered a null Int.
func (i *Int) UnmarshalJSON(data []byte) error {
if bytes.Equal(data, nullBytes) {
i.Valid = false
return nil
}
if err := json.Unmarshal(data, &i.Int64); err != nil {
var typeError *json.UnmarshalTypeError
if errors.As(err, &typeError) {
// special case: accept string input
if typeError.Value != "string" {
return fmt.Errorf("zero: JSON input is invalid type (need int or string): %w", err)
}
var str string
if err := json.Unmarshal(data, &str); err != nil {
return fmt.Errorf("zero: couldn't unmarshal number string: %w", err)
}
n, err := strconv.ParseInt(str, 10, 64)
if err != nil {
return fmt.Errorf("zero: couldn't convert string to int: %w", err)
}
i.Int64 = n
i.Valid = n != 0
return nil
}
return fmt.Errorf("zero: couldn't unmarshal JSON: %w", err)
}
i.Valid = i.Int64 != 0
return nil
}
// UnmarshalText implements encoding.TextUnmarshaler.
// It will unmarshal to a null Int if the input is a blank, or zero.
// 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
i.Int64, err = strconv.ParseInt(string(text), 10, 64)
if err != nil {
return fmt.Errorf("zero: couldn't unmarshal text: %w", err)
}
i.Valid = i.Int64 != 0
return err
}
// MarshalJSON implements json.Marshaler.
// It will encode 0 if this Int is null.
func (i Int) MarshalJSON() ([]byte, error) {
n := i.Int64
if !i.Valid {
n = 0
}
return []byte(strconv.FormatInt(n, 10)), nil
}
// MarshalText implements encoding.TextMarshaler.
// It will encode a zero if this Int is null.
func (i Int) MarshalText() ([]byte, error) {
n := i.Int64
if !i.Valid {
n = 0
}
return []byte(strconv.FormatInt(n, 10)), nil
}
// SetValid changes this Int's value and also sets it to be non-null.
func (i *Int) SetValid(n int64) {
i.Int64 = 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() *int64 {
if !i.Valid {
return nil
}
return &i.Int64
}
// IsZero returns true for null or zero Ints, for future omitempty support (Go 1.4?)
func (i Int) IsZero() bool {
return !i.Valid || i.Int64 == 0
}
// Equal returns true if both ints have the same value or are both either null or zero.
func (i Int) Equal(other Int) bool {
return i.ValueOrZero() == other.ValueOrZero()
}