lbry.go/zero/bool.go
Greg 95e26ed907 prefer JSON errors when unmarshaling, better docs
Invalid JSON input will return a *json.SyntaxError instead of a cryptic error
from this package.
2015-09-10 20:05:24 +09:00

121 lines
2.7 KiB
Go

package zero
import (
"database/sql"
"encoding/json"
"errors"
"fmt"
"reflect"
)
// Bool is a nullable bool. False input is considered null.
// JSON marshals to false if null.
// Considered null to SQL unmarshaled from a false value.
type Bool struct {
sql.NullBool
}
// NewBool creates a new Bool
func NewBool(b bool, valid bool) Bool {
return Bool{
NullBool: sql.NullBool{
Bool: b,
Valid: valid,
},
}
}
// BoolFrom creates a new Bool that will be null if false.
func BoolFrom(b bool) Bool {
return NewBool(b, b)
}
// BoolFromPtr creates a new Bool that be null if b is nil.
func BoolFromPtr(b *bool) Bool {
if b == nil {
return NewBool(false, false)
}
return NewBool(*b, true)
}
// UnmarshalJSON implements json.Unmarshaler.
// "false" will be considered a null Bool.
// It also supports unmarshalling a sql.NullBool.
func (b *Bool) UnmarshalJSON(data []byte) error {
var err error
var v interface{}
if err = json.Unmarshal(data, &v); err != nil {
return err
}
switch x := v.(type) {
case bool:
b.Bool = x
case map[string]interface{}:
err = json.Unmarshal(data, &b.NullBool)
case nil:
b.Valid = false
return nil
default:
err = fmt.Errorf("json: cannot unmarshal %v into Go value of type zero.Bool", reflect.TypeOf(v).Name())
}
b.Valid = (err == nil) && b.Bool
return err
}
// UnmarshalText implements encoding.TextUnmarshaler.
// It will unmarshal to a null Bool if the input is a false or not a bool.
// It will return an error if the input is not a float, blank, or "null".
func (b *Bool) UnmarshalText(text []byte) error {
str := string(text)
switch str {
case "", "null":
b.Valid = false
return nil
case "true":
b.Bool = true
case "false":
b.Bool = false
default:
b.Valid = false
return errors.New("invalid input:" + str)
}
b.Valid = b.Bool
return nil
}
// MarshalJSON implements json.Marshaler.
// It will encode null if this Bool is null.
func (b Bool) MarshalJSON() ([]byte, error) {
if !b.Valid || !b.Bool {
return []byte("false"), nil
}
return []byte("true"), nil
}
// MarshalText implements encoding.TextMarshaler.
// It will encode a zero if this Bool is null.
func (b Bool) MarshalText() ([]byte, error) {
if !b.Valid || !b.Bool {
return []byte("false"), nil
}
return []byte("true"), nil
}
// SetValid changes this Bool's value and also sets it to be non-null.
func (b *Bool) SetValid(v bool) {
b.Bool = v
b.Valid = true
}
// Ptr returns a poBooler to this Bool's value, or a nil poBooler if this Bool is null.
func (b Bool) Ptr() *bool {
if !b.Valid {
return nil
}
return &b.Bool
}
// IsZero returns true for null or zero Bools, for future omitempty support (Go 1.4?)
func (b Bool) IsZero() bool {
return !b.Valid || !b.Bool
}