/**
 * @license
 * Copyright 2022-2026 Matter.js Authors
 * SPDX-License-Identifier: Apache-2.0
 */
import { MaybePromise } from "../util/Promises.js";
import type { BaseStorageDriver } from "./BaseStorageDriver.js";
/**
 * Interface for legacy storage drivers that support reading blob data alongside KV data.
 * Used during cross-type kv→blob migration to extract blobs from old combined drivers.
 */
export interface LegacyBlobSource {
    openBlob(contexts: string[], key: string): MaybePromise<Blob>;
}
/**
 * Type-aware storage migrator.  Handles KV-to-KV, blob-to-blob, and the legacy KV-to-blob cross-type
 * migration (extracting blob data from old combined KV+blob drivers).
 *
 * It does not modify or remove source data.
 */
export declare namespace StorageMigration {
    interface MigrationSkipped {
        contexts: string[];
        key: string;
        error: string;
    }
    interface MigrationResult {
        success: boolean;
        migratedCount: number;
        skippedCount: number;
        otherTypeKeysSkipped: number;
        skippedItems: MigrationSkipped[];
    }
    /**
     * Migrate storage from `source` to `target`.  The migration strategy is determined by the
     * drivers' {@link BaseStorageDriver.storageType storageType}:
     *
     * - **kv → kv**: copies KV data via `get`/`set`, skips blob remnants (undefined-value keys)
     * - **blob → blob**: copies blobs via `openBlob`/`writeBlobFromStream`
     * - **kv → blob**: cross-type extraction — reads blob data from a legacy KV driver that stored
     *   blobs alongside KV data (e.g. old `FileStorageDriver`).  Keys where `get()` returns a value
     *   are skipped (they're KV, not blobs).  Keys where `get()` returns `undefined` are treated as
     *   blobs and streamed to the blob target.
     * - **blob → kv**: not supported — throws
     */
    function migrate(source: BaseStorageDriver, target: BaseStorageDriver): Promise<MigrationResult>;
    /**
     * Export migration result to log
     */
    function resultToLog(result: MigrationResult): string;
}
//# sourceMappingURL=StorageMigration.d.ts.map