/**
 * Copyright (c) 2025 Elara AI Pty Ltd
 * Licensed under BSL 1.1. See LICENSE for details.
 */
import type { RepoStore, GcObjectEntry, StorageBackend } from '../interfaces.js';
/**
 * Options for garbage collection
 */
export interface GcOptions {
    /**
     * Minimum age in milliseconds for files to be considered for deletion.
     * Files younger than this are skipped to avoid race conditions with concurrent writes.
     * Default: 60000 (1 minute)
     */
    minAge?: number;
    /**
     * If true, only report what would be deleted without actually deleting.
     * Default: false
     */
    dryRun?: boolean;
}
/**
 * Result of garbage collection
 */
export interface GcResult {
    /** Number of objects deleted */
    deletedObjects: number;
    /** Number of orphaned staging files deleted */
    deletedPartials: number;
    /** Number of objects retained */
    retainedObjects: number;
    /** Number of files skipped due to being too young */
    skippedYoung: number;
    /** Total bytes freed */
    bytesFreed: number;
}
/**
 * Result from sweepBatch — pure decision, no side effects.
 */
export interface SweepBatchResult {
    /** Hashes of objects to delete */
    toDelete: string[];
    /** Number of objects retained (reachable) */
    retained: number;
    /** Number of objects skipped due to being too young */
    skippedYoung: number;
    /** Total bytes that would be freed */
    bytesFreed: number;
}
/**
 * Collect all root hashes from packages, workspaces, and executions.
 *
 * Calls each gcScan*Roots method with pagination support.
 * Adding a new root scan method to RepoStore requires updating this function.
 */
export declare function collectAllRoots(store: RepoStore, repo: string): Promise<Set<string>>;
/**
 * Trace the object graph from roots using iterative DFS with schema-aware traversal.
 *
 * Decodes each object using BEAST2 self-describing format and extracts child
 * hashes based on the detected object type (Package, Task, or Tree). Objects
 * known to be leaves (values, IR blobs) are marked reachable without reading.
 *
 * @param readObject - Function to read an object by hash (returns null if missing)
 * @param roots - Set of root hashes to start from
 * @returns Set of all reachable hashes
 */
export declare function markReachable(readObject: (hash: string) => Promise<Uint8Array | null>, roots: Set<string>): Promise<Set<string>>;
/**
 * Pure decision function: determine which objects to delete.
 *
 * No side effects — trivially testable. Caller decides whether to
 * actually delete (supports dry-run by skipping gcDeleteObjects).
 *
 * @param objects - Object entries from gcScanObjects
 * @param reachable - Set of reachable hashes from markReachable
 * @param minAge - Minimum age in ms; objects younger than this are skipped
 * @returns Decision result with toDelete list and stats
 */
export declare function sweepBatch(objects: GcObjectEntry[], reachable: Set<string>, minAge: number): SweepBatchResult;
/**
 * Run garbage collection on an e3 repository.
 *
 * Works with any StorageBackend — no instanceof checks.
 *
 * @param storage - Storage backend
 * @param repo - Repository identifier
 * @param options - GC options
 * @returns GC result with statistics
 */
export declare function repoGc(storage: StorageBackend, repo: string, options?: GcOptions): Promise<GcResult>;
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