import { PlainObject, Some } from '@xh/hoist/core';
import type { StringInternSpec } from '../FetchService';
/**
 * Generational string-interning cache for a logical dataset, identified by an app-provided
 * key and shared across fetches of that dataset - see {@link FetchOptions.internStrings}.
 *
 * Values are deduplicated into an internal pending map spanning a whole response (all chunks
 * of an NDJSON stream), with lookups falling back to the previously committed values, so values
 * repeated across successive fetches share a single canonical string. Calling `commit()`
 * installs the pending values per the spec's `retainMode` - by default replacing the committed
 * set, bounding cache retention to the strings present in the latest completed response. See
 * {@link StringInternSpec.retainMode} for the 'always' and 'never' variants.
 *
 * The pending map is opened lazily by `intern()`. A response that fails or is abandoned before
 * commit should be `abort()`ed to discard its pending values - the previously committed
 * generation remains in place either way.
 *
 * @internal
 */
export declare class StringInterner {
    /** Latest spec provided for this key - adopted on each call, so settings may vary. */
    get spec(): StringInternSpec;
    set spec(spec: StringInternSpec);
    private _spec;
    private excludeFields;
    private committed;
    private pending;
    private processed;
    private carried;
    private lastStats;
    constructor(spec: StringInternSpec);
    /**
     * Stats for the most recently committed cycle (i.e. response) - all zero if none committed:
     *  - `processed` - total string values encountered.
     *  - `retained` - distinct values in the committed response, with `retainedPct` of
     *     processed. Lower percentage = more duplication removed.
     *  - `carried` - retained values already present in the previous generation, with
     *    `carriedPct` of retained. Higher percentage = more stability across refreshes.
     *
     * Introspect from the console via `XH.fetchService.getInternStats()`.
     */
    get stats(): PlainObject;
    /**
     * Intern string values within the given data, mutating it in place.
     */
    intern(data: Some<PlainObject>): void;
    /**
     * Install pending values for reuse by later responses, per the spec's `retainMode`:
     * 'nextCall' (default) replaces the committed set, evicting values not re-seen; 'always'
     * merges into it; 'never' discards, leaving `committed` permanently empty so interning is
     * per-response only.
     */
    commit(): void;
    /** Discard pending values without committing. No-op if already committed or aborted. */
    abort(): void;
    private internRow;
}