/**
 * @file
 *
 * Records that the harness-owned Obsidian instance on a CDP port died, so a
 * process that did not spawn it can still say **why** it is unreachable.
 *
 * Only the process that launched the instance holds the child handle and sees
 * `exit`; the test workers get nothing but the port (see the repo's L9). So the
 * one fact worth having — the exit code — has to cross a process boundary, and
 * this is the channel: a small JSON sentinel next to the setup lock
 * (`setup-lock.ts`) and the Appium server marker (`appium-server-marker.ts`),
 * keyed by port.
 *
 * Written **only for a death the harness did not order.** A deliberate kill
 * (teardown, or the relaunch loop killing an instance before starting the next)
 * clears the marker instead, because a marker left behind by a clean run would
 * convict the next run's healthy instance of an exit that never happened.
 *
 * Reads are deliberately tolerant, exactly as the Appium marker's are: missing,
 * unreadable, or describing another port all read as "no marker", and the
 * caller falls back to saying only that the instance is gone.
 */
/**
 * Records the death of the owned instance that was serving CDP on a port.
 */
export interface OwnedInstanceExitMarker {
    /**
    Exit code, or `null` when terminated by a signal or when it failed to spawn.
     */
    readonly code: null | number;
    /**
    When the instance exited (`Date.now()` epoch milliseconds).
     */
    readonly exitedAtInMilliseconds: number;
    /**
    The tail of everything the instance wrote to stdout/stderr (empty when it wrote nothing).
     */
    readonly outputTail: string;
    /**
    PID of the instance's process, or `undefined` when it never got one.
     */
    readonly pid: number | undefined;
    /**
    The CDP port the dead instance was serving.
     */
    readonly port: number;
    /**
    Terminating signal, or `null` when it exited normally or failed to spawn.
     */
    readonly signal: NodeJS.Signals | null;
    /**
    The spawn-failure message when the instance never started (e.g. `ENOENT`), otherwise absent.
     */
    readonly spawnError?: string | undefined;
}
/**
 * Parameters for {@link writeOwnedInstanceExitMarker}.
 */
export interface WriteOwnedInstanceExitMarkerParams {
    /**
    Exit code, or `null` when terminated by a signal or when it failed to spawn.
     */
    readonly code: null | number;
    /**
    The tail of everything the instance wrote to stdout/stderr.
     */
    readonly outputTail: string;
    /**
    PID of the instance's process, or `undefined` when it never got one.
     */
    readonly pid: number | undefined;
    /**
    The CDP port the dead instance was serving.
     */
    readonly port: number;
    /**
    Terminating signal, or `null` when it exited normally or failed to spawn.
     */
    readonly signal: NodeJS.Signals | null;
    /**
    The spawn-failure message when the instance never started, otherwise absent.
     */
    readonly spawnError?: string | undefined;
}
/**
 * Removes the marker for a port. Called when an instance is launched on it (a
 * recycled port must not inherit an older instance's death) and whenever the
 * harness kills an instance on purpose.
 *
 * @param port - The CDP port.
 */
export declare function clearOwnedInstanceExitMarker(port: number): void;
/**
 * Reads the marker for a port.
 *
 * @param port - The CDP port.
 * @returns The marker, or `undefined` when there is none, it is unreadable, or it does not describe this port.
 */
export declare function readOwnedInstanceExitMarker(port: number): OwnedInstanceExitMarker | undefined;
/**
 * Records that the instance serving a port has died, stamping it with the
 * current time so a reader can report how long ago it happened.
 *
 * @param params - The dead instance's port, exit details, and output tail.
 */
export declare function writeOwnedInstanceExitMarker(params: WriteOwnedInstanceExitMarkerParams): void;