import type { PrerenderManifest } from "./manifests.js";
/**
 * The header Next accepts as an authentic revalidation request.
 *
 * Sent with the build's own `previewModeId`, it makes the server re-render the
 * page instead of serving the cached one. Without it, load against an ISR route
 * exercises the static cache and nothing else — measured on the
 * vercel/next.js#96533 reproduction, the same app reports `leak` with this
 * header and `stable` without it.
 */
export declare const REVALIDATE_HEADER = "x-prerender-revalidate";
/**
 * The revalidation period in force for a route, or null when it has none.
 *
 * Accepts either a concrete path (`/posts/post-1`) or a dynamic template
 * (`/posts/[slug]`): the period lives on concrete entries, and a template
 * inherits it from any entry whose `srcRoute` points back at it.
 */
export declare function revalidateSecondsFor(manifest: PrerenderManifest | undefined, route: string): number | null;
/** Whether a route is served from the ISR cache and needs driving. */
export declare function revalidates(manifest: PrerenderManifest | undefined, route: string): boolean;
export type RevalidationPlan = {
    kind: "not-isr";
} | {
    kind: "drive";
    headers: Record<string, string>;
}
/** ISR, but every request asks for a key the cache has never held. */
 | {
    kind: "no-cache-to-drive";
}
/** ISR, but the manifest cannot supply what an authentic request needs. */
 | {
    kind: "cannot-drive";
    reason: string;
};
/**
 * How to make a route re-render, given what the build tells us.
 *
 * A header the user set themselves wins untouched: someone driving a bespoke
 * revalidation path knows more about it than the manifest does.
 *
 * `requestPath` decides whether driving is needed at all. The header does not
 * merely bypass the cache: it makes Next serve the request through its
 * revalidation path instead of its normal one, and a route whose render count
 * depends on the normal path is then measured somewhere its users never go.
 * Measured on the vercel/next.js#99077 reproduction: with the header, the
 * `partialPrefetching: true` and `false` builds both created 1.95 timers per
 * request and were reported at the same +1970 MB/1000 req; without it they
 * created 3.80 and 0.99 and separated 5x, matching the issue. So the header is
 * sent only where it buys something — when the load revisits keys the cache
 * can already hold. With `{n}` every request carries a key the route has never
 * served, so there is no cache to bypass and driving only distorts.
 */
export declare function planRevalidation(manifest: PrerenderManifest | undefined, route: string, userHeaders: Record<string, string> | undefined, requestPath?: string): RevalidationPlan;