살아남는 세션

    /// The stored session. A file that will not read is moved beside itself
    /// under a stamped name and an empty session is returned with a notice.
    public func load(now: Date = Date()) -> Loaded {
        do {
            return Loaded(document: try store.load(materializeDefaults: false).document, notice: nil)
        } catch {
            let kept = url.deletingLastPathComponent()
                .appendingPathComponent("session.unreadable-\(Self.stamp(now)).json")
            do {
                try FileManager.default.moveItem(at: url, to: kept)
                return Loaded(
                    document: SessionDocument(),
                    notice: "The saved session could not be read and was kept as \(kept.lastPathComponent). Voyager started with an empty one.")
            } catch {
                return Loaded(
                    document: SessionDocument(),
                    notice: "The saved session could not be read. It is left untouched, so this session will not be saved.")
            }
        }
    }

public final class SessionWriter: @unchecked Sendable {
    private let store: SessionStore
    private let queue = DispatchQueue(label: "com.cwk.voyager.session")
    /// The document last written; touched only on `queue`.
    private var written: SessionDocument?

    public init(store: SessionStore) {
        self.store = store
    }

    /// Writes `document` soon. `failed` hears why, on the main actor, when
    /// the store refused it.
    public func write(_ document: SessionDocument, failed: @escaping @MainActor @Sendable (String) -> Void) {
        queue.async { [self] in
            do {
                try save(document)
            } catch {
                let reason = error.localizedDescription
                Task { @MainActor in failed(reason) }
            }
        }
    }

    /// Writes `document` now, after any write still waiting, and returns when
    /// it is on disk.
    public func writeNow(_ document: SessionDocument) throws {
        try queue.sync { try save(document) }
    }

    private func save(_ document: SessionDocument) throws {
        guard document != written else { return }
        try store.save(document)
        written = document
    }
}

# Voyager saves its session when it is asked to quit, and on SIGTERM. It is
# asked first; nothing is killed.
running_pid() { /usr/bin/pgrep -f '^/Applications/Voyager\.app/Contents/MacOS/Voyager' 2>/dev/null | /usr/bin/head -n 1 }
if [[ -n "$(running_pid)" ]]; then
  /bin/kill -TERM "$(running_pid)" 2>/dev/null || true
  for _ in {1..40}; do
    [[ -z "$(running_pid)" ]] && break
    /bin/sleep 0.25
  done
fi
if [[ -n "$(running_pid)" ]]; then
  print -u2 "HARD_FAIL Voyager is still running (a page may be holding a dialog open); quit it, then run this again"
  exit 1
fi