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