rclone/fs/tristate.go

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package fs
import (
"encoding/json"
"fmt"
"strconv"
"strings"
)
// Tristate is a boolean that can has the states, true, false and
// unset/invalid/nil
type Tristate struct {
Value bool
Valid bool
}
// String renders the tristate as true/false/unset
func (t Tristate) String() string {
if !t.Valid {
return "unset"
}
if t.Value {
return "true"
}
return "false"
}
// Set the List entries
func (t *Tristate) Set(s string) error {
s = strings.ToLower(s)
if s == "" || s == "nil" || s == "null" || s == "unset" {
t.Valid = false
return nil
}
value, err := strconv.ParseBool(s)
if err != nil {
return fmt.Errorf("failed to parse Tristate %q: %w", s, err)
}
t.Value = value
t.Valid = true
return nil
}
// Type of the value
func (Tristate) Type() string {
return "Tristate"
}
// Scan implements the fmt.Scanner interface
func (t *Tristate) Scan(s fmt.ScanState, ch rune) error {
token, err := s.Token(true, nil)
if err != nil {
return err
}
return t.Set(string(token))
}
// UnmarshalJSON parses it as a bool or nil for unset
func (t *Tristate) UnmarshalJSON(in []byte) error {
var b *bool
err := json.Unmarshal(in, &b)
if err != nil {
return err
}
if b != nil {
t.Valid = true
t.Value = *b
} else {
t.Valid = false
}
return nil
}
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// MarshalJSON encodes it as a bool or nil for unset
func (t *Tristate) MarshalJSON() ([]byte, error) {
if !t.Valid {
return json.Marshal(nil)
}
return json.Marshal(t.Value)
}