next/dist/esm/client/components/segment-cache/cache.js

The React Framework

import { HasLoadingBoundary } from '../../../shared/lib/app-router-types';
import { NEXT_DID_POSTPONE_HEADER, NEXT_ROUTER_PREFETCH_HEADER, NEXT_ROUTER_SEGMENT_PREFETCH_HEADER, NEXT_ROUTER_STALE_TIME_HEADER, NEXT_ROUTER_STATE_TREE_HEADER, NEXT_URL, RSC_CONTENT_TYPE_HEADER, RSC_HEADER } from '../app-router-headers';
import { createFetch, createFromNextReadableStream } from '../router-reducer/fetch-server-response';
import { pingPrefetchTask, isPrefetchTaskDirty, startRevalidationCooldown } from './scheduler';
import { getRouteVaryPath, getFulfilledRouteVaryPath, getSegmentVaryPathForRequest, appendLayoutVaryPath, finalizeLayoutVaryPath, finalizePageVaryPath, clonePageVaryPathWithNewSearchParams, finalizeMetadataVaryPath } from './vary-path';
import { getAppBuildId } from '../../app-build-id';
import { createHrefFromUrl } from '../router-reducer/create-href-from-url';
// TODO: Rename this module to avoid confusion with other types of cache keys
import { createCacheKey as createPrefetchRequestKey } from './cache-key';
import { doesStaticSegmentAppearInURL, getCacheKeyForDynamicParam, getRenderedPathname, getRenderedSearch, parseDynamicParamFromURLPart } from '../../route-params';
import { createCacheMap, getFromCacheMap, setInCacheMap, setSizeInCacheMap, deleteFromCacheMap, isValueExpired } from './cache-map';
import { appendSegmentRequestKeyPart, convertSegmentPathToStaticExportFilename, createSegmentRequestKeyPart, HEAD_REQUEST_KEY, ROOT_SEGMENT_REQUEST_KEY } from '../../../shared/lib/segment-cache/segment-value-encoding';
import { normalizeFlightData, prepareFlightRouterStateForRequest } from '../../flight-data-helpers';
import { STATIC_STALETIME_MS } from '../router-reducer/reducers/navigate-reducer';
import { pingVisibleLinks } from '../links';
import { PAGE_SEGMENT_KEY } from '../../../shared/lib/segment';
import { FetchStrategy } from './types';
import { createPromiseWithResolvers } from '../../../shared/lib/promise-with-resolvers';
/**
 * Ensures a minimum stale time of 30s to avoid issues where the server sends a too
 * short-lived stale time, which would prevent anything from being prefetched.
 */ export function getStaleTimeMs(staleTimeSeconds) {
    return Math.max(staleTimeSeconds, 30) * 1000;
}
/**
 * Tracks the status of a cache entry as it progresses from no data (Empty),
 * waiting for server data (Pending), and finished (either Fulfilled or
 * Rejected depending on the response from the server.
 */ export var EntryStatus = /*#__PURE__*/ function(EntryStatus) {
    EntryStatus[EntryStatus["Empty"] = 0] = "Empty";
    EntryStatus[EntryStatus["Pending"] = 1] = "Pending";
    EntryStatus[EntryStatus["Fulfilled"] = 2] = "Fulfilled";
    EntryStatus[EntryStatus["Rejected"] = 3] = "Rejected";
    return EntryStatus;
}({});
const isOutputExportMode = process.env.NODE_ENV === 'production' && process.env.__NEXT_CONFIG_OUTPUT === 'export';
const MetadataOnlyRequestTree = [
    '',
    {},
    null,
    'metadata-only'
];
let routeCacheMap = createCacheMap();
let segmentCacheMap = createCacheMap();
// All invalidation listeners for the whole cache are tracked in single set.
// Since we don't yet support tag or path-based invalidation, there's no point
// tracking them any more granularly than this. Once we add granular
// invalidation, that may change, though generally the model is to just notify
// the listeners and allow the caller to poll the prefetch cache with a new
// prefetch task if desired.
let invalidationListeners = null;
// Incrementing counter used to track cache invalidations.
let currentCacheVersion = 0;
export function getCurrentCacheVersion() {
    return currentCacheVersion;
}
/**
 * Used to clear the client prefetch cache when a server action calls
 * revalidatePath or revalidateTag. Eventually we will support only clearing the
 * segments that were actually affected, but there's more work to be done on the
 * server before the client is able to do this correctly.
 */ export function revalidateEntireCache(nextUrl, tree) {
    // Increment the current cache version. This does not eagerly evict anything
    // from the cache, but because all the entries are versioned, and we check
    // the version when reading from the cache, this effectively causes all
    // entries to be evicted lazily. We do it lazily because in the future,
    // actions like revalidateTag or refresh will not evict the entire cache,
    // but rather some subset of the entries.
    currentCacheVersion++;
    // Start a cooldown before re-prefetching to allow CDN cache propagation.
    startRevalidationCooldown();
    // Prefetch all the currently visible links again, to re-fill the cache.
    pingVisibleLinks(nextUrl, tree);
    // Similarly, notify all invalidation listeners (i.e. those passed to
    // `router.prefetch(onInvalidate)`), so they can trigger a new prefetch
    // if needed.
    pingInvalidationListeners(nextUrl, tree);
}
function attachInvalidationListener(task) {
    // This function is called whenever a prefetch task reads a cache entry. If
    // the task has an onInvalidate function associated with it — i.e. the one
    // optionally passed to router.prefetch(onInvalidate) — then we attach that
    // listener to the every cache entry that the task reads. Then, if an entry
    // is invalidated, we call the function.
    if (task.onInvalidate !== null) {
        if (invalidationListeners === null) {
            invalidationListeners = new Set([
                task
            ]);
        } else {
            invalidationListeners.add(task);
        }
    }
}
function notifyInvalidationListener(task) {
    const onInvalidate = task.onInvalidate;
    if (onInvalidate !== null) {
        // Clear the callback from the task object to guarantee it's not called more
        // than once.
        task.onInvalidate = null;
        // This is a user-space function, so we must wrap in try/catch.
        try {
            onInvalidate();
        } catch (error) {
            if (typeof reportError === 'function') {
                reportError(error);
            } else {
                console.error(error);
            }
        }
    }
}
export function pingInvalidationListeners(nextUrl, tree) {
    // The rough equivalent of pingVisibleLinks, but for onInvalidate callbacks.
    // This is called when the Next-Url or the base tree changes, since those
    // may affect the result of a prefetch task. It's also called after a
    // cache invalidation.
    if (invalidationListeners !== null) {
        const tasks = invalidationListeners;
        invalidationListeners = null;
        for (const task of tasks){
            if (isPrefetchTaskDirty(task, nextUrl, tree)) {
                notifyInvalidationListener(task);
            }
        }
    }
}
export function readRouteCacheEntry(now, key) {
    const varyPath = getRouteVaryPath(key.pathname, key.search, key.nextUrl);
    const isRevalidation = false;
    return getFromCacheMap(now, getCurrentCacheVersion(), routeCacheMap, varyPath, isRevalidation);
}
export function readSegmentCacheEntry(now, varyPath) {
    const isRevalidation = false;
    return getFromCacheMap(now, getCurrentCacheVersion(), segmentCacheMap, varyPath, isRevalidation);
}
function readRevalidatingSegmentCacheEntry(now, varyPath) {
    const isRevalidation = true;
    return getFromCacheMap(now, getCurrentCacheVersion(), segmentCacheMap, varyPath, isRevalidation);
}
export function waitForSegmentCacheEntry(pendingEntry) {
    // Because the entry is pending, there's already a in-progress request.
    // Attach a promise to the entry that will resolve when the server responds.
    let promiseWithResolvers = pendingEntry.promise;
    if (promiseWithResolvers === null) {
        promiseWithResolvers = pendingEntry.promise = createPromiseWithResolvers();
    } else {
    // There's already a promise we can use
    }
    return promiseWithResolvers.promise;
}
/**
 * Checks if an entry for a route exists in the cache. If so, it returns the
 * entry, If not, it adds an empty entry to the cache and returns it.
 */ export function readOrCreateRouteCacheEntry(now, task, key) {
    attachInvalidationListener(task);
    const existingEntry = readRouteCacheEntry(now, key);
    if (existingEntry !== null) {
        return existingEntry;
    }
    // Create a pending entry and add it to the cache.
    const pendingEntry = {
        canonicalUrl: null,
        status: 0,
        blockedTasks: null,
        tree: null,
        metadata: null,
        // This is initialized to true because we don't know yet whether the route
        // could be intercepted. It's only set to false once we receive a response
        // from the server.
        couldBeIntercepted: true,
        // Similarly, we don't yet know if the route supports PPR.
        isPPREnabled: false,
        renderedSearch: null,
        // Map-related fields
        ref: null,
        size: 0,
        // Since this is an empty entry, there's no reason to ever evict it. It will
        // be updated when the data is populated.
        staleAt: Infinity,
        version: getCurrentCacheVersion()
    };
    const varyPath = getRouteVaryPath(key.pathname, key.search, key.nextUrl);
    const isRevalidation = false;
    setInCacheMap(routeCacheMap, varyPath, pendingEntry, isRevalidation);
    return pendingEntry;
}
export function requestOptimisticRouteCacheEntry(now, requestedUrl, nextUrl) {
    // This function is called during a navigation when there was no matching
    // route tree in the prefetch cache. Before de-opting to a blocking,
    // unprefetched navigation, we will first attempt to construct an "optimistic"
    // route tree by checking the cache for similar routes.
    //
    // Check if there's a route with the same pathname, but with different
    // search params. We can then base our optimistic route tree on this entry.
    //
    // Conceptually, we are simulating what would happen if we did perform a
    // prefetch the requested URL, under the assumption that the server will
    // not redirect or rewrite the request in a different manner than the
    // base route tree. This assumption might not hold, in which case we'll have
    // to recover when we perform the dynamic navigation request. However, this
    // is what would happen if a route were dynamically rewritten/redirected
    // in between the prefetch and the navigation. So the logic needs to exist
    // to handle this case regardless.
    // Look for a route with the same pathname, but with an empty search string.
    // TODO: There's nothing inherently special about the empty search string;
    // it's chosen somewhat arbitrarily, with the rationale that it's the most
    // likely one to exist. But we should update this to match _any_ search
    // string. The plan is to generalize this logic alongside other improvements
    // related to "fallback" cache entries.
    const requestedSearch = requestedUrl.search;
    if (requestedSearch === '') {
        // The caller would have already checked if a route with an empty search
        // string is in the cache. So we can bail out here.
        return null;
    }
    const urlWithoutSearchParams = new URL(requestedUrl);
    urlWithoutSearchParams.search = '';
    const routeWithNoSearchParams = readRouteCacheEntry(now, createPrefetchRequestKey(urlWithoutSearchParams.href, nextUrl));
    if (routeWithNoSearchParams === null || routeWithNoSearchParams.status !== 2) {
        // Bail out of constructing an optimistic route tree. This will result in
        // a blocking, unprefetched navigation.
        return null;
    }
    // Now we have a base route tree we can "patch" with our optimistic values.
    // Optimistically assume that redirects for the requested pathname do
    // not vary on the search string. Therefore, if the base route was
    // redirected to a different search string, then the optimistic route
    // should be redirected to the same search string. Otherwise, we use
    // the requested search string.
    const canonicalUrlForRouteWithNoSearchParams = new URL(routeWithNoSearchParams.canonicalUrl, requestedUrl.origin);
    const optimisticCanonicalSearch = canonicalUrlForRouteWithNoSearchParams.search !== '' ? canonicalUrlForRouteWithNoSearchParams.search : requestedSearch;
    // Similarly, optimistically assume that rewrites for the requested
    // pathname do not vary on the search string. Therefore, if the base
    // route was rewritten to a different search string, then the optimistic
    // route should be rewritten to the same search string. Otherwise, we use
    // the requested search string.
    const optimisticRenderedSearch = routeWithNoSearchParams.renderedSearch !== '' ? routeWithNoSearchParams.renderedSearch : requestedSearch;
    const optimisticUrl = new URL(routeWithNoSearchParams.canonicalUrl, location.origin);
    optimisticUrl.search = optimisticCanonicalSearch;
    const optimisticCanonicalUrl = createHrefFromUrl(optimisticUrl);
    const optimisticRouteTree = createOptimisticRouteTree(routeWithNoSearchParams.tree, optimisticRenderedSearch);
    const optimisticMetadataTree = createOptimisticRouteTree(routeWithNoSearchParams.metadata, optimisticRenderedSearch);
    // Clone the base route tree, and override the relevant fields with our
    // optimistic values.
    const optimisticEntry = {
        canonicalUrl: optimisticCanonicalUrl,
        status: 2,
        // This isn't cloned because it's instance-specific
        blockedTasks: null,
        tree: optimisticRouteTree,
        metadata: optimisticMetadataTree,
        couldBeIntercepted: routeWithNoSearchParams.couldBeIntercepted,
        isPPREnabled: routeWithNoSearchParams.isPPREnabled,
        // Override the rendered search with the optimistic value.
        renderedSearch: optimisticRenderedSearch,
        // Map-related fields
        ref: null,
        size: 0,
        staleAt: routeWithNoSearchParams.staleAt,
        version: routeWithNoSearchParams.version
    };
    // Do not insert this entry into the cache. It only exists so we can
    // perform the current navigation. Just return it to the caller.
    return optimisticEntry;
}
function createOptimisticRouteTree(tree, newRenderedSearch) {
    // Create a new route tree that identical to the original one except for
    // the rendered search string, which is contained in the vary path.
    let clonedSlots = null;
    const originalSlots = tree.slots;
    if (originalSlots !== null) {
        clonedSlots = {};
        for(const parallelRouteKey in originalSlots){
            const childTree = originalSlots[parallelRouteKey];
            clonedSlots[parallelRouteKey] = createOptimisticRouteTree(childTree, newRenderedSearch);
        }
    }
    // We only need to clone the vary path if the route is a page.
    if (tree.isPage) {
        return {
            requestKey: tree.requestKey,
            segment: tree.segment,
            varyPath: clonePageVaryPathWithNewSearchParams(tree.varyPath, newRenderedSearch),
            isPage: true,
            slots: clonedSlots,
            isRootLayout: tree.isRootLayout,
            hasLoadingBoundary: tree.hasLoadingBoundary,
            hasRuntimePrefetch: tree.hasRuntimePrefetch
        };
    }
    return {
        requestKey: tree.requestKey,
        segment: tree.segment,
        varyPath: tree.varyPath,
        isPage: false,
        slots: clonedSlots,
        isRootLayout: tree.isRootLayout,
        hasLoadingBoundary: tree.hasLoadingBoundary,
        hasRuntimePrefetch: tree.hasRuntimePrefetch
    };
}
/**
 * Checks if an entry for a segment exists in the cache. If so, it returns the
 * entry, If not, it adds an empty entry to the cache and returns it.
 */ export function readOrCreateSegmentCacheEntry(now, fetchStrategy, route, tree) {
    const existingEntry = readSegmentCacheEntry(now, tree.varyPath);
    if (existingEntry !== null) {
        return existingEntry;
    }
    // Create a pending entry and add it to the cache.
    const varyPathForRequest = getSegmentVaryPathForRequest(fetchStrategy, tree);
    const pendingEntry = createDetachedSegmentCacheEntry(route.staleAt);
    const isRevalidation = false;
    setInCacheMap(segmentCacheMap, varyPathForRequest, pendingEntry, isRevalidation);
    return pendingEntry;
}
export function readOrCreateRevalidatingSegmentEntry(now, fetchStrategy, route, tree) {
    // This function is called when we've already confirmed that a particular
    // segment is cached, but we want to perform another request anyway in case it
    // returns more complete and/or fresher data than we already have. The logic
    // for deciding whether to replace the existing entry is handled elsewhere;
    // this function just handles retrieving a cache entry that we can use to
    // track the revalidation.
    //
    // The reason revalidations are stored in the cache is because we need to be
    // able to dedupe multiple revalidation requests. The reason they have to be
    // handled specially is because we shouldn't overwrite a "normal" entry if
    // one exists at the same keypath. So, for each internal cache location, there
    // is a special "revalidation" slot that is used solely for this purpose.
    //
    // You can think of it as if all the revalidation entries were stored in a
    // separate cache map from the canonical entries, and then transfered to the
    // canonical cache map once the request is complete — this isn't how it's
    // actually implemented, since it's more efficient to store them in the same
    // data structure as the normal entries, but that's how it's modeled
    // conceptually.
    // TODO: Once we implement Fallback behavior for params, where an entry is
    // re-keyed based on response information, we'll need to account for the
    // possibility that the keypath of the previous entry is more generic than
    // the keypath of the revalidating entry. In other words, the server could
    // return a less generic entry upon revalidation. For now, though, this isn't
    // a concern because the keypath is based solely on the prefetch strategy,
    // not on data contained in the response.
    const existingEntry = readRevalidatingSegmentCacheEntry(now, tree.varyPath);
    if (existingEntry !== null) {
        return existingEntry;
    }
    // Create a pending entry and add it to the cache.
    const varyPathForRequest = getSegmentVaryPathForRequest(fetchStrategy, tree);
    const pendingEntry = createDetachedSegmentCacheEntry(route.staleAt);
    const isRevalidation = true;
    setInCacheMap(segmentCacheMap, varyPathForRequest, pendingEntry, isRevalidation);
    return pendingEntry;
}
export function overwriteRevalidatingSegmentCacheEntry(fetchStrategy, route, tree) {
    // This function is called when we've already decided to replace an existing
    // revalidation entry. Create a new entry and write it into the cache,
    // overwriting the previous value.
    const varyPathForRequest = getSegmentVaryPathForRequest(fetchStrategy, tree);
    const pendingEntry = createDetachedSegmentCacheEntry(route.staleAt);
    const isRevalidation = true;
    setInCacheMap(segmentCacheMap, varyPathForRequest, pendingEntry, isRevalidation);
    return pendingEntry;
}
export function upsertSegmentEntry(now, varyPath, candidateEntry) {
    // We have a new entry that has not yet been inserted into the cache. Before
    // we do so, we need to confirm whether it takes precedence over the existing
    // entry (if one exists).
    // TODO: We should not upsert an entry if its key was invalidated in the time
    // since the request was made. We can do that by passing the "owner" entry to
    // this function and confirming it's the same as `existingEntry`.
    if (isValueExpired(now, getCurrentCacheVersion(), candidateEntry)) {
        // The entry is expired. We cannot upsert it.
        return null;
    }
    const existingEntry = readSegmentCacheEntry(now, varyPath);
    if (existingEntry !== null) {
        // Don't replace a more specific segment with a less-specific one. A case where this
        // might happen is if the existing segment was fetched via
        // `<Link prefetch={true}>`.
        if (// We fetched the new segment using a different, less specific fetch strategy
        // than the segment we already have in the cache, so it can't have more content.
        candidateEntry.fetchStrategy !== existingEntry.fetchStrategy && !canNewFetchStrategyProvideMoreContent(existingEntry.fetchStrategy, candidateEntry.fetchStrategy) || // The existing entry isn't partial, but the new one is.
        // (TODO: can this be true if `candidateEntry.fetchStrategy >= existingEntry.fetchStrategy`?)
        !existingEntry.isPartial && candidateEntry.isPartial) {
            // We're going to leave revalidating entry in the cache so that it doesn't
            // get revalidated again unnecessarily. Downgrade the Fulfilled entry to
            // Rejected and null out the data so it can be garbage collected. We leave
            // `staleAt` intact to prevent subsequent revalidation attempts only until
            // the entry expires.
            const rejectedEntry = candidateEntry;
            rejectedEntry.status = 3;
            rejectedEntry.loading = null;
            rejectedEntry.rsc = null;
            return null;
        }
        // Evict the existing entry from the cache.
        deleteFromCacheMap(existingEntry);
    }
    const isRevalidation = false;
    setInCacheMap(segmentCacheMap, varyPath, candidateEntry, isRevalidation);
    return candidateEntry;
}
export function createDetachedSegmentCacheEntry(staleAt) {
    const emptyEntry = {
        status: 0,
        // Default to assuming the fetch strategy will be PPR. This will be updated
        // when a fetch is actually initiated.
        fetchStrategy: FetchStrategy.PPR,
        rsc: null,
        loading: null,
        isPartial: true,
        promise: null,
        // Map-related fields
        ref: null,
        size: 0,
        staleAt,
        version: 0
    };
    return emptyEntry;
}
export function upgradeToPendingSegment(emptyEntry, fetchStrategy) {
    const pendingEntry = emptyEntry;
    pendingEntry.status = 1;
    pendingEntry.fetchStrategy = fetchStrategy;
    if (fetchStrategy === FetchStrategy.Full) {
        // We can assume the response will contain the full segment data. Set this
        // to false so we know it's OK to omit this segment from any navigation
        // requests that may happen while the data is still pending.
        pendingEntry.isPartial = false;
    }
    // Set the version here, since this is right before the request is initiated.
    // The next time the global cache version is incremented, the entry will
    // effectively be evicted. This happens before initiating the request, rather
    // than when receiving the response, because it's guaranteed to happen
    // before the data is read on the server.
    pendingEntry.version = getCurrentCacheVersion();
    return pendingEntry;
}
function pingBlockedTasks(entry) {
    const blockedTasks = entry.blockedTasks;
    if (blockedTasks !== null) {
        for (const task of blockedTasks){
            pingPrefetchTask(task);
        }
        entry.blockedTasks = null;
    }
}
function fulfillRouteCacheEntry(entry, tree, metadataVaryPath, staleAt, couldBeIntercepted, canonicalUrl, renderedSearch, isPPREnabled) {
    // The Head is not actually part of the route tree, but other than that, it's
    // fetched and cached like a segment. Some functions expect a RouteTree
    // object, so rather than fork the logic in all those places, we use this
    // "fake" one.
    const metadata = {
        requestKey: HEAD_REQUEST_KEY,
        segment: HEAD_REQUEST_KEY,
        varyPath: metadataVaryPath,
        // The metadata isn't really a "page" (though it isn't really a "segment"
        // either) but for the purposes of how this field is used, it behaves like
        // one. If this logic ever gets more complex we can change this to an enum.
        isPage: true,
        slots: null,
        isRootLayout: false,
        hasLoadingBoundary: HasLoadingBoundary.SubtreeHasNoLoadingBoundary,
        hasRuntimePrefetch: false
    };
    const fulfilledEntry = entry;
    fulfilledEntry.status = 2;
    fulfilledEntry.tree = tree;
    fulfilledEntry.metadata = metadata;
    fulfilledEntry.staleAt = staleAt;
    fulfilledEntry.couldBeIntercepted = couldBeIntercepted;
    fulfilledEntry.canonicalUrl = canonicalUrl;
    fulfilledEntry.renderedSearch = renderedSearch;
    fulfilledEntry.isPPREnabled = isPPREnabled;
    pingBlockedTasks(entry);
    return fulfilledEntry;
}
function fulfillSegmentCacheEntry(segmentCacheEntry, rsc, loading, staleAt, isPartial) {
    const fulfilledEntry = segmentCacheEntry;
    fulfilledEntry.status = 2;
    fulfilledEntry.rsc = rsc;
    fulfilledEntry.loading = loading;
    fulfilledEntry.staleAt = staleAt;
    fulfilledEntry.isPartial = isPartial;
    // Resolve any listeners that were waiting for this data.
    if (segmentCacheEntry.promise !== null) {
        segmentCacheEntry.promise.resolve(fulfilledEntry);
        // Free the promise for garbage collection.
        fulfilledEntry.promise = null;
    }
    return fulfilledEntry;
}
function rejectRouteCacheEntry(entry, staleAt) {
    const rejectedEntry = entry;
    rejectedEntry.status = 3;
    rejectedEntry.staleAt = staleAt;
    pingBlockedTasks(entry);
}
function rejectSegmentCacheEntry(entry, staleAt) {
    const rejectedEntry = entry;
    rejectedEntry.status = 3;
    rejectedEntry.staleAt = staleAt;
    if (entry.promise !== null) {
        // NOTE: We don't currently propagate the reason the prefetch was canceled
        // but we could by accepting a `reason` argument.
        entry.promise.resolve(null);
        entry.promise = null;
    }
}
function convertRootTreePrefetchToRouteTree(rootTree, renderedPathname, renderedSearch, acc) {
    // Remove trailing and leading slashes
    const pathnameParts = renderedPathname.split('/').filter((p)=>p !== '');
    const index = 0;
    const rootSegment = ROOT_SEGMENT_REQUEST_KEY;
    return convertTreePrefetchToRouteTree(rootTree.tree, rootSegment, null, ROOT_SEGMENT_REQUEST_KEY, pathnameParts, index, renderedSearch, acc);
}
function convertTreePrefetchToRouteTree(prefetch, segment, partialVaryPath, requestKey, pathnameParts, pathnamePartsIndex, renderedSearch, acc) {
    // Converts the route tree sent by the server into the format used by the
    // cache. The cached version of the tree includes additional fields, such as a
    // cache key for each segment. Since this is frequently accessed, we compute
    // it once instead of on every access. This same cache key is also used to
    // request the segment from the server.
    let slots = null;
    let isPage;
    let varyPath;
    const prefetchSlots = prefetch.slots;
    if (prefetchSlots !== null) {
        isPage = false;
        varyPath = finalizeLayoutVaryPath(requestKey, partialVaryPath);
        slots = {};
        for(let parallelRouteKey in prefetchSlots){
            const childPrefetch = prefetchSlots[parallelRouteKey];
            const childParamName = childPrefetch.name;
            const childParamType = childPrefetch.paramType;
            const childServerSentParamKey = childPrefetch.paramKey;
            let childDoesAppearInURL;
            let childSegment;
            let childPartialVaryPath;
            if (childParamType !== null) {
                // This segment is parameterized. Get the param from the pathname.
                const childParamValue = parseDynamicParamFromURLPart(childParamType, pathnameParts, pathnamePartsIndex);
                // Assign a cache key to the segment, based on the param value. In the
                // pre-Segment Cache implementation, the server computes this and sends
                // it in the body of the response. In the Segment Cache implementation,
                // the server sends an empty string and we fill it in here.
                // TODO: We're intentionally not adding the search param to page
                // segments here; it's tracked separately and added back during a read.
                // This would clearer if we waited to construct the segment until it's
                // read from the cache, since that's effectively what we're
                // doing anyway.
                const childParamKey = // The server omits this field from the prefetch response when
                // cacheComponents is enabled.
                childServerSentParamKey !== null ? childServerSentParamKey : getCacheKeyForDynamicParam(childParamValue, '');
                childPartialVaryPath = appendLayoutVaryPath(partialVaryPath, childParamKey);
                childSegment = [
                    childParamName,
                    childParamKey,
                    childParamType
                ];
                childDoesAppearInURL = true;
            } else {
                // This segment does not have a param. Inherit the partial vary path of
                // the parent.
                childPartialVaryPath = partialVaryPath;
                childSegment = childParamName;
                childDoesAppearInURL = doesStaticSegmentAppearInURL(childParamName);
            }
            // Only increment the index if the segment appears in the URL. If it's a
            // "virtual" segment, like a route group, it remains the same.
            const childPathnamePartsIndex = childDoesAppearInURL ? pathnamePartsIndex + 1 : pathnamePartsIndex;
            const childRequestKeyPart = createSegmentRequestKeyPart(childSegment);
            const childRequestKey = appendSegmentRequestKeyPart(requestKey, parallelRouteKey, childRequestKeyPart);
            slots[parallelRouteKey] = convertTreePrefetchToRouteTree(childPrefetch, childSegment, childPartialVaryPath, childRequestKey, pathnameParts, childPathnamePartsIndex, renderedSearch, acc);
        }
    } else {
        if (requestKey.endsWith(PAGE_SEGMENT_KEY)) {
            // This is a page segment.
            isPage = true;
            varyPath = finalizePageVaryPath(requestKey, renderedSearch, partialVaryPath);
            // The metadata "segment" is not part the route tree, but it has the same
            // conceptual params as a page segment. Write the vary path into the
            // accumulator object. If there are multiple parallel pages, we use the
            // first one. Which page we choose is arbitrary as long as it's
            // consistently the same one every time every time. See
            // finalizeMetadataVaryPath for more details.
            if (acc.metadataVaryPath === null) {
                acc.metadataVaryPath = finalizeMetadataVaryPath(requestKey, renderedSearch, partialVaryPath);
            }
        } else {
            // This is a layout segment.
            isPage = false;
            varyPath = finalizeLayoutVaryPath(requestKey, partialVaryPath);
        }
    }
    return {
        requestKey,
        segment,
        varyPath,
        // TODO: Cheating the type system here a bit because TypeScript can't tell
        // that the type of isPage and varyPath are consistent. The fix would be to
        // create separate constructors and call the appropriate one from each of
        // the branches above. Just seems a bit overkill only for one field so I'll
        // leave it as-is for now. If isPage were wrong it would break the behavior
        // and we'd catch it quickly, anyway.
        isPage: isPage,
        slots,
        isRootLayout: prefetch.isRootLayout,
        // This field is only relevant to dynamic routes. For a PPR/static route,
        // there's always some partial loading state we can fetch.
        hasLoadingBoundary: HasLoadingBoundary.SegmentHasLoadingBoundary,
        hasRuntimePrefetch: prefetch.hasRuntimePrefetch
    };
}
function convertRootFlightRouterStateToRouteTree(flightRouterState, renderedSearch, acc) {
    return convertFlightRouterStateToRouteTree(flightRouterState, ROOT_SEGMENT_REQUEST_KEY, null, renderedSearch, acc);
}
function convertFlightRouterStateToRouteTree(flightRouterState, requestKey, parentPartialVaryPath, renderedSearch, acc) {
    const originalSegment = flightRouterState[0];
    let segment;
    let partialVaryPath;
    let isPage;
    let varyPath;
    if (Array.isArray(originalSegment)) {
        isPage = false;
        const paramCacheKey = originalSegment[1];
        partialVaryPath = appendLayoutVaryPath(parentPartialVaryPath, paramCacheKey);
        varyPath = finalizeLayoutVaryPath(requestKey, partialVaryPath);
        segment = originalSegment;
    } else {
        // This segment does not have a param. Inherit the partial vary path of
        // the parent.
        partialVaryPath = parentPartialVaryPath;
        if (requestKey.endsWith(PAGE_SEGMENT_KEY)) {
            // This is a page segment.
            isPage = true;
            // The navigation implementation expects the search params to be included
            // in the segment. However, in the case of a static response, the search
            // params are omitted. So the client needs to add them back in when reading
            // from the Segment Cache.
            //
            // For consistency, we'll do this for dynamic responses, too.
            //
            // TODO: We should move search params out of FlightRouterState and handle
            // them entirely on the client, similar to our plan for dynamic params.
            segment = PAGE_SEGMENT_KEY;
            varyPath = finalizePageVaryPath(requestKey, renderedSearch, partialVaryPath);
            // The metadata "segment" is not part the route tree, but it has the same
            // conceptual params as a page segment. Write the vary path into the
            // accumulator object. If there are multiple parallel pages, we use the
            // first one. Which page we choose is arbitrary as long as it's
            // consistently the same one every time every time. See
            // finalizeMetadataVaryPath for more details.
            if (acc.metadataVaryPath === null) {
                acc.metadataVaryPath = finalizeMetadataVaryPath(requestKey, renderedSearch, partialVaryPath);
            }
        } else {
            // This is a layout segment.
            isPage = false;
            segment = originalSegment;
            varyPath = finalizeLayoutVaryPath(requestKey, partialVaryPath);
        }
    }
    let slots = null;
    const parallelRoutes = flightRouterState[1];
    for(let parallelRouteKey in parallelRoutes){
        const childRouterState = parallelRoutes[parallelRouteKey];
        const childSegment = childRouterState[0];
        // TODO: Eventually, the param values will not be included in the response
        // from the server. We'll instead fill them in on the client by parsing
        // the URL. This is where we'll do that.
        const childRequestKeyPart = createSegmentRequestKeyPart(childSegment);
        const childRequestKey = appendSegmentRequestKeyPart(requestKey, parallelRouteKey, childRequestKeyPart);
        const childTree = convertFlightRouterStateToRouteTree(childRouterState, childRequestKey, partialVaryPath, renderedSearch, acc);
        if (slots === null) {
            slots = {
                [parallelRouteKey]: childTree
            };
        } else {
            slots[parallelRouteKey] = childTree;
        }
    }
    return {
        requestKey,
        segment,
        varyPath,
        // TODO: Cheating the type system here a bit because TypeScript can't tell
        // that the type of isPage and varyPath are consistent. The fix would be to
        // create separate constructors and call the appropriate one from each of
        // the branches above. Just seems a bit overkill only for one field so I'll
        // leave it as-is for now. If isPage were wrong it would break the behavior
        // and we'd catch it quickly, anyway.
        isPage: isPage,
        slots,
        isRootLayout: flightRouterState[4] === true,
        hasLoadingBoundary: flightRouterState[5] !== undefined ? flightRouterState[5] : HasLoadingBoundary.SubtreeHasNoLoadingBoundary,
        // Non-static tree responses are only used by apps that haven't adopted
        // Cache Components. So this is always false.
        hasRuntimePrefetch: false
    };
}
export function convertRouteTreeToFlightRouterState(routeTree) {
    const parallelRoutes = {};
    if (routeTree.slots !== null) {
        for(const parallelRouteKey in routeTree.slots){
            parallelRoutes[parallelRouteKey] = convertRouteTreeToFlightRouterState(routeTree.slots[parallelRouteKey]);
        }
    }
    const flightRouterState = [
        routeTree.segment,
        parallelRoutes,
        null,
        null,
        routeTree.isRootLayout
    ];
    return flightRouterState;
}
export async function fetchRouteOnCacheMiss(entry, task, key) {
    // This function is allowed to use async/await because it contains the actual
    // fetch that gets issued on a cache miss. Notice it writes the result to the
    // cache entry directly, rather than return data that is then written by
    // the caller.
    const pathname = key.pathname;
    const search = key.search;
    const nextUrl = key.nextUrl;
    const segmentPath = '/_tree';
    const headers = {
        [RSC_HEADER]: '1',
        [NEXT_ROUTER_PREFETCH_HEADER]: '1',
        [NEXT_ROUTER_SEGMENT_PREFETCH_HEADER]: segmentPath
    };
    if (nextUrl !== null) {
        headers[NEXT_URL] = nextUrl;
    }
    try {
        const url = new URL(pathname + search, location.origin);
        let response;
        let urlAfterRedirects;
        if (isOutputExportMode) {
            // In output: "export" mode, we can't use headers to request a particular
            // segment. Instead, we encode the extra request information into the URL.
            // This is not part of the "public" interface of the app; it's an internal
            // Next.js implementation detail that the app developer should not need to
            // concern themselves with.
            //
            // For example, to request a segment:
            //
            //   Path passed to <Link>:   /path/to/page
            //   Path passed to fetch:    /path/to/page/__next-segments/_tree
            //
            //   (This is not the exact protocol, just an illustration.)
            //
            // Before we do that, though, we need to account for redirects. Even in
            // output: "export" mode, a proxy might redirect the page to a different
            // location, but we shouldn't assume or expect that they also redirect all
            // the segment files, too.
            //
            // To check whether the page is redirected, previously we perform a range
            // request of 64 bytes of the HTML document to check if the target page
            // is part of this app (by checking if build id matches). Only if the target
            // page is part of this app do we determine the final canonical URL.
            //
            // However, as mentioned in https://github.com/vercel/next.js/pull/85903,
            // some popular static hosting providers (like Cloudflare Pages or Render.com)
            // do not support range requests, in the worst case, the entire HTML instead
            // of 64 bytes could be returned, which is wasteful.
            //
            // So instead, we drops the check for build id here, and simply perform
            // a HEAD request to rejects 1xx/4xx/5xx responses, and then determine the
            // final URL after redirects.
            //
            // NOTE: We could embed the route tree into the HTML document, to avoid
            // a second request. We're not doing that currently because it would make
            // the HTML document larger and affect normal page loads.
            const headResponse = await fetch(url, {
                method: 'HEAD'
            });
            if (headResponse.status < 200 || headResponse.status >= 400) {
                // The target page responded w/o a successful status code
                // Could be a WAF serving a 403, or a 5xx from a backend
                //
                // Note that we can't use headResponse.ok here, because
                // Response#ok returns `false` with 3xx responses.
                rejectRouteCacheEntry(entry, Date.now() + 10 * 1000);
                return null;
            }
            urlAfterRedirects = headResponse.redirected ? new URL(headResponse.url) : url;
            response = await fetchPrefetchResponse(addSegmentPathToUrlInOutputExportMode(urlAfterRedirects, segmentPath), headers);
        } else {
            // "Server" mode. We can use request headers instead of the pathname.
            // TODO: The eventual plan is to get rid of our custom request headers and
            // encode everything into the URL, using a similar strategy to the
            // "output: export" block above.
            response = await fetchPrefetchResponse(url, headers);
            urlAfterRedirects = response !== null && response.redirected ? new URL(response.url) : url;
        }
        if (!response || !response.ok || // 204 is a Cache miss. Though theoretically this shouldn't happen when
        // PPR is enabled, because we always respond to route tree requests, even
        // if it needs to be blockingly generated on demand.
        response.status === 204 || !response.body) {
            // Server responded with an error, or with a miss. We should still cache
            // the response, but we can try again after 10 seconds.
            rejectRouteCacheEntry(entry, Date.now() + 10 * 1000);
            return null;
        }
        // TODO: The canonical URL is the href without the origin. I think
        // historically the reason for this is because the initial canonical URL
        // gets passed as a prop to the top-level React component, which means it
        // needs to be computed during SSR. If it were to include the origin, it
        // would need to always be same as location.origin on the client, to prevent
        // a hydration mismatch. To sidestep this complexity, we omit the origin.
        //
        // However, since this is neither a native URL object nor a fully qualified
        // URL string, we need to be careful about how we use it. To prevent subtle
        // mistakes, we should create a special type for it, instead of just string.
        // Or, we should just use a (readonly) URL object instead. The type of the
        // prop that we pass to seed the initial state does not need to be the same
        // type as the state itself.
        const canonicalUrl = createHrefFromUrl(urlAfterRedirects);
        // Check whether the response varies based on the Next-Url header.
        const varyHeader = response.headers.get('vary');
        const couldBeIntercepted = varyHeader !== null && varyHeader.includes(NEXT_URL);
        // Track when the network connection closes.
        const closed = createPromiseWithResolvers();
        // This checks whether the response was served from the per-segment cache,
        // rather than the old prefetching flow. If it fails, it implies that PPR
        // is disabled on this route.
        const routeIsPPREnabled = response.headers.get(NEXT_DID_POSTPONE_HEADER) === '2' || // In output: "export" mode, we can't rely on response headers. But if we
        // receive a well-formed response, we can assume it's a static response,
        // because all data is static in this mode.
        isOutputExportMode;
        if (routeIsPPREnabled) {
            const prefetchStream = createPrefetchResponseStream(response.body, closed.resolve, function onResponseSizeUpdate(size) {
                setSizeInCacheMap(entry, size);
            });
            const serverData = await createFromNextReadableStream(prefetchStream, headers);
            if (serverData.buildId !== getAppBuildId()) {
                // The server build does not match the client. Treat as a 404. During
                // an actual navigation, the router will trigger an MPA navigation.
                // TODO: Consider moving the build ID to a response header so we can check
                // it before decoding the response, and so there's one way of checking
                // across all response types.
                // TODO: We should cache the fact that this is an MPA navigation.
                rejectRouteCacheEntry(entry, Date.now() + 10 * 1000);
                return null;
            }
            // Get the params that were used to render the target page. These may
            // be different from the params in the request URL, if the page
            // was rewritten.
            const renderedPathname = getRenderedPathname(response);
            const renderedSearch = getRenderedSearch(response);
            // Convert the server-sent data into the RouteTree format used by the
            // client cache.
            //
            // During this traversal, we accumulate additional data into this
            // "accumulator" object.
            const acc = {
                metadataVaryPath: null
            };
            const routeTree = convertRootTreePrefetchToRouteTree(serverData, renderedPathname, renderedSearch, acc);
            const metadataVaryPath = acc.metadataVaryPath;
            if (metadataVaryPath === null) {
                rejectRouteCacheEntry(entry, Date.now() + 10 * 1000);
                return null;
            }
            const staleTimeMs = getStaleTimeMs(serverData.staleTime);
            fulfillRouteCacheEntry(entry, routeTree, metadataVaryPath, Date.now() + staleTimeMs, couldBeIntercepted, canonicalUrl, renderedSearch, routeIsPPREnabled);
        } else {
            // PPR is not enabled for this route. The server responds with a
            // different format (FlightRouterState) that we need to convert.
            // TODO: We will unify the responses eventually. I'm keeping the types
            // separate for now because FlightRouterState has so many
            // overloaded concerns.
            const prefetchStream = createPrefetchResponseStream(response.body, closed.resolve, function onResponseSizeUpdate(size) {
                setSizeInCacheMap(entry, size);
            });
            const serverData = await createFromNextReadableStream(prefetchStream, headers);
            if (serverData.b !== getAppBuildId()) {
                // The server build does not match the client. Treat as a 404. During
                // an actual navigation, the router will trigger an MPA navigation.
                // TODO: Consider moving the build ID to a response header so we can check
                // it before decoding the response, and so there's one way of checking
                // across all response types.
                // TODO: We should cache the fact that this is an MPA navigation.
                rejectRouteCacheEntry(entry, Date.now() + 10 * 1000);
                return null;
            }
            writeDynamicTreeResponseIntoCache(Date.now(), task, // The non-PPR response format is what we'd get if we prefetched these segments
            // using the LoadingBoundary fetch strategy, so mark their cache entries accordingly.
            FetchStrategy.LoadingBoundary, response, serverData, entry, couldBeIntercepted, canonicalUrl, routeIsPPREnabled);
        }
        if (!couldBeIntercepted) {
            // This route will never be intercepted. So we can use this entry for all
            // requests to this route, regardless of the Next-Url header. This works
            // because when reading the cache we always check for a valid
            // non-intercepted entry first.
            // Re-key the entry. The `set` implementation handles removing it from
            // its previous position in the cache. We don't need to do anything to
            // update the LRU, because the entry is already in it.
            // TODO: Treat this as an upsert — should check if an entry already
            // exists at the new keypath, and if so, whether we should keep that
            // one instead.
            const fulfilledVaryPath = getFulfilledRouteVaryPath(pathname, search, nextUrl, couldBeIntercepted);
            const isRevalidation = false;
            setInCacheMap(routeCacheMap, fulfilledVaryPath, entry, isRevalidation);
        }
        // Return a promise that resolves when the network connection closes, so
        // the scheduler can track the number of concurrent network connections.
        return {
            value: null,
            closed: closed.promise
        };
    } catch (error) {
        // Either the connection itself failed, or something bad happened while
        // decoding the response.
        rejectRouteCacheEntry(entry, Date.now() + 10 * 1000);
        return null;
    }
}
export async function fetchSegmentOnCacheMiss(route, segmentCacheEntry, routeKey, tree) {
    // This function is allowed to use async/await because it contains the actual
    // fetch that gets issued on a cache miss. Notice it writes the result to the
    // cache entry directly, rather than return data that is then written by
    // the caller.
    //
    // Segment fetches are non-blocking so we don't need to ping the scheduler
    // on completion.
    // Use the canonical URL to request the segment, not the original URL. These
    // are usually the same, but the canonical URL will be different if the route
    // tree response was redirected. To avoid an extra waterfall on every segment
    // request, we pass the redirected URL instead of the original one.
    const url = new URL(route.canonicalUrl, location.origin);
    const nextUrl = routeKey.nextUrl;
    const requ