/**
 * In-memory cache for documents the viewer pages through.
 *
 * The chunk tool addresses a document by character offset, so it has to keep
 * reading the *same* string the first response was cut from — a re-fetch can
 * produce a different metadata header and shift every offset. The cache is what
 * makes that string outlive a single tool call.
 *
 * It is created per `registerAllTools()` call, which means per session on HTTP
 * and per process on stdio, and is bounded by a character budget rather than by
 * entry count alone: with `MAX_SESSIONS = 100` any per-session entry limit is
 * multiplied by a hundred, and RIS documents differ in size by two orders of
 * magnitude.
 */
import type { OutlineEntry } from './formatting.js';
/** A document as the viewer consumes it: rendered text plus its jump targets. */
export interface CachedDocument {
    /** Markdown rendering, exactly as ris_dokument produced it — before truncation. */
    text: string;
    outline: OutlineEntry[];
    /** URL the HTML came from. */
    sourceUrl: string;
}
export interface DocumentCache {
    /** Looks up `key` directly, then as an alias. */
    get(key: string): CachedDocument | undefined;
    /** `alias` is the resolved content URL; ignored when equal to `key`. */
    set(key: string, value: CachedDocument, alias?: string): void;
    /** Live entries — for tests and diagnostics. */
    readonly size: number;
    /** Characters currently held — the bound that actually matters. */
    readonly chars: number;
}
export interface DocumentCacheOptions {
    maxEntries?: number;
    maxChars?: number;
    ttlMs?: number;
    /** Injectable clock; tests drive TTL expiry without timers. */
    now?: () => number;
}
/**
 * Create a bounded, least-recently-used document cache.
 *
 * A document is reachable under two keys: its Dokumentnummer and its resolved
 * content URL. `ris_dokument` and the chunk tool may each be called with either
 * one, and nothing guarantees the viewer holds the same identifier the document
 * was opened with — a single key would miss on exactly that crossing and turn
 * every chunk into a fetch, which looks correct and is merely slow.
 */
export declare function createDocumentCache(options?: DocumentCacheOptions): DocumentCache;
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