43 lines
1.2 KiB
Go
43 lines
1.2 KiB
Go
// Package store keeps the ledger of what has already been downloaded, so a
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// repeated run can skip tracks instead of fetching them again.
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//
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// It is a bbolt database written as a hidden file inside the output
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// directory, which keeps it travelling with the music library it describes.
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// Losing it is harmless: the worst outcome is re-downloading.
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package store
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import (
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"errors"
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"fmt"
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"path/filepath"
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"time"
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"go.etcd.io/bbolt"
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bolterrors "go.etcd.io/bbolt/errors"
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)
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type Store struct {
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db *bbolt.DB
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}
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// Open opens the ledger in dir, creating it if needed.
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//
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// bbolt takes an exclusive file lock, so a second godeez running against the
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// same output directory blocks here. The timeout turns that into a clear
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// message rather than an apparent hang.
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func Open(dir string) (*Store, error) {
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db, err := bbolt.Open(filepath.Join(dir, ".tracks.db"), 0600, &bbolt.Options{Timeout: 5 * time.Second})
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if err != nil {
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if errors.Is(err, bolterrors.ErrTimeout) {
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return nil, errors.New("database is already in use by another process")
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}
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return nil, fmt.Errorf("failed to open database: %w", err)
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}
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return &Store{db: db}, nil
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}
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func (s *Store) Close() error {
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return s.db.Close()
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}
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