88 lines
1.8 KiB
Go
88 lines
1.8 KiB
Go
package preferences
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import (
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"encoding/json"
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"errors"
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"fmt"
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"io/fs"
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"os"
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"path/filepath"
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"slices"
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"sync"
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)
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type Store struct {
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mutex sync.RWMutex
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path string
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current Preferences
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}
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func Open(path string, defaults Preferences) (*Store, error) {
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store := &Store{path: path, current: defaults}
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data, err := os.ReadFile(path)
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if errors.Is(err, fs.ErrNotExist) {
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return store, nil
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}
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if err != nil {
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return nil, err
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}
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loaded := defaults
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if err := json.Unmarshal(data, &loaded); err != nil {
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return nil, fmt.Errorf("settings file %s: %w", path, err)
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}
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if err := loaded.Validate(); err != nil {
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return nil, fmt.Errorf("settings file %s: %w", path, err)
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}
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store.current = loaded
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return store, nil
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}
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func (store *Store) Get() Preferences {
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store.mutex.RLock()
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defer store.mutex.RUnlock()
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current := store.current
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current.AllowedPorts = slices.Clone(current.AllowedPorts)
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if current.AllowedPorts == nil {
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current.AllowedPorts = []uint16{}
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}
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return current
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}
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func (store *Store) Update(next Preferences) error {
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if err := next.Validate(); err != nil {
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return err
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}
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data, err := json.MarshalIndent(next, "", " ")
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if err != nil {
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return err
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}
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store.mutex.Lock()
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defer store.mutex.Unlock()
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if err := writeAtomically(store.path, data); err != nil {
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return err
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}
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store.current = next
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return nil
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}
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func writeAtomically(path string, data []byte) error {
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temporary, err := os.CreateTemp(filepath.Dir(path), ".settings-*.tmp")
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if err != nil {
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return err
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}
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_, writeErr := temporary.Write(data)
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closeErr := temporary.Close()
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if writeErr != nil || closeErr != nil {
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os.Remove(temporary.Name())
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return errors.Join(writeErr, closeErr)
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}
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if err := os.Rename(temporary.Name(), path); err != nil {
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os.Remove(temporary.Name())
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return err
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}
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return nil
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}
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