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tailscale/types/opt/bool.go

109 lines
2.3 KiB
Go

// Copyright (c) 2020 Tailscale Inc & AUTHORS All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Package opt defines optional types.
package opt
import (
"fmt"
"strconv"
)
// Bool represents an optional boolean to be JSON-encoded. The string
// is either "true", "false", or the enmpty string to mean unset.
//
// As a special case, the underlying string may also be the string
// "unset" as as a synonym for the empty string. This lets the
// explicit unset value be exchanged over an encoding/json "omitempty"
// field without it being dropped.
type Bool string
func (b *Bool) Set(v bool) {
*b = Bool(strconv.FormatBool(v))
}
func (b *Bool) Clear() { *b = "" }
func (b Bool) Get() (v bool, ok bool) {
switch b {
case "true":
return true, true
case "false":
return false, true
default:
return false, false
}
}
// Scan implements database/sql.Scanner.
func (b *Bool) Scan(src any) error {
if src == nil {
*b = ""
return nil
}
switch src := src.(type) {
case bool:
if src {
*b = "true"
} else {
*b = "false"
}
return nil
case int64:
if src == 0 {
*b = "false"
} else {
*b = "true"
}
return nil
default:
return fmt.Errorf("opt.Bool.Scan: invalid type %T: %v", src, src)
}
}
// EqualBool reports whether b is equal to v.
// If b is empty or not a valid bool, it reports false.
func (b Bool) EqualBool(v bool) bool {
p, ok := b.Get()
return ok && p == v
}
var (
trueBytes = []byte("true")
falseBytes = []byte("false")
nullBytes = []byte("null")
)
func (b Bool) MarshalJSON() ([]byte, error) {
switch b {
case "true":
return trueBytes, nil
case "false":
return falseBytes, nil
case "", "unset":
return nullBytes, nil
}
return nil, fmt.Errorf("invalid opt.Bool value %q", string(b))
}
func (b *Bool) UnmarshalJSON(j []byte) error {
// Note: written with a bunch of ifs instead of a switch
// because I'm sure the Go compiler optimizes away these
// []byte->string allocations in an == comparison, but I'm too
// lazy to check whether that's true in a switch also.
if string(j) == "true" {
*b = "true"
return nil
}
if string(j) == "false" {
*b = "false"
return nil
}
if string(j) == "null" {
*b = "unset"
return nil
}
return fmt.Errorf("invalid opt.Bool value %q", j)
}