export declare function formatBackupTimestamp(d: Date): string;
export interface BackupSessionOptions {
    workspaceRoot: string;
    operation: "init" | "update";
}
export interface BackupFileInfo {
    existed: boolean;
    mode: number | null;
}
export declare class BackupSession {
    workspaceRoot: string;
    operation: "init" | "update";
    timestamp: string;
    backupRoot: string;
    files: Map<string, BackupFileInfo>;
    protected _prepared: boolean;
    constructor(options: BackupSessionOptions);
    _prepare(): Promise<void>;
    recordFile(relPosix: string, options?: {
        recordMissing?: boolean;
    }): Promise<void>;
    finalize(options?: {
        extra?: unknown;
    }): Promise<string | null>;
}
export declare function resolveBackupRoot(workspaceRoot: string, stamp: string): Promise<string>;
export declare function rollbackFromBackup(workspaceRoot: string, backupRoot: string): Promise<void>;