package repository import ( "context" "sync" "github.com/restic/restic/internal/debug" "github.com/restic/restic/internal/restic" ) // ParallelWorkFunc gets one file ID to work on. If an error is returned, // processing stops. When the contect is cancelled the function should return. type ParallelWorkFunc func(ctx context.Context, id string) error // ParallelIDWorkFunc gets one restic.ID to work on. If an error is returned, // processing stops. When the context is cancelled the function should return. type ParallelIDWorkFunc func(ctx context.Context, id restic.ID) error // FilesInParallel runs n workers of f in parallel, on the IDs that // repo.List(t) yield. If f returns an error, the process is aborted and the // first error is returned. func FilesInParallel(ctx context.Context, repo restic.Lister, t restic.FileType, n uint, f ParallelWorkFunc) error { wg := &sync.WaitGroup{} ch := repo.List(ctx, t) errors := make(chan error, n) for i := 0; uint(i) < n; i++ { wg.Add(1) go func() { defer wg.Done() for { select { case id, ok := <-ch: if !ok { return } err := f(ctx, id) if err != nil { errors <- err return } case <-ctx.Done(): return } } }() } wg.Wait() select { case err := <-errors: return err default: break } return nil } // ParallelWorkFuncParseID converts a function that takes a restic.ID to a // function that takes a string. Filenames that do not parse as a restic.ID // are ignored. func ParallelWorkFuncParseID(f ParallelIDWorkFunc) ParallelWorkFunc { return func(ctx context.Context, s string) error { id, err := restic.ParseID(s) if err != nil { debug.Log("invalid ID %q: %v", id, err) return err } return f(ctx, id) } }