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import type { CacheContext } from "./cache";
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// Cache-policy discriminator used by visibility-aware request paths to
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// decide whether the shared Workers Cache may be read or written. Public
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// repositories cache freely; private repositories must bypass shared
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// cache reads/writes regardless of upstream success.
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export type SharedCachePolicy = "allow-shared-cache" | "bypass-shared-cache";
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// CacheContext memo flag tags. `no-cache-read`/`no-cache-write` are honored
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// by the shared cache helpers; route handlers that mark a request private
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// must set both before calling any cache-aware loader.
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const NO_CACHE_READ = "no-cache-read";
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const NO_CACHE_WRITE = "no-cache-write";
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// Marks a request as private so any downstream shared-cache lookup or
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// write is skipped. Idempotent: callers can mark private once at gate
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// time and trust that all subsequent helpers honor it.
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export function markRequestPrivate(cacheCtx: CacheContext): void {
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  cacheCtx.memo = cacheCtx.memo || {};
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  cacheCtx.memo.flags = cacheCtx.memo.flags || new Set<string>();
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  cacheCtx.memo.flags.add(NO_CACHE_READ);
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  cacheCtx.memo.flags.add(NO_CACHE_WRITE);
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}
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// Returns true if the request was marked private (private repo, sensitive
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// data path, etc.). Used to gate shared-cache reads/writes and to pick the
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// `Cache-Control` response header.
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export function isRequestPrivate(cacheCtx: CacheContext | undefined): boolean {
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  return cacheCtx?.memo?.flags?.has(NO_CACHE_READ) === true;
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}
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// HTTP `Cache-Control` value for responses serving repo data over Git or
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// data APIs:
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// - `mutating: true` -> always "no-store" (credentialed mutating paths
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//   such as receive-pack must never sit in shared caches).
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// - private (membership-derived) request -> "no-store".
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// - otherwise -> "no-cache" so downstream caches re-validate but may
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//   reuse bodies briefly.
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export function responseCacheControl(
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  cacheCtx: CacheContext | undefined,
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  options?: { mutating?: boolean }
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): "no-store" | "no-cache" {
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  if (options?.mutating) return "no-store";
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  return isRequestPrivate(cacheCtx) ? "no-store" : "no-cache";
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}