Function requestCacheFromPool

packages/react-reconciler/src/ReactFiberTransition.js:226–252

(renderLanes: Lanes)

}

export function requestCacheFromPool(renderLanes: Lanes): Cache {
  // Similar to previous function, except if there's not already a cache in the
  // pool, we allocate a new one.
  const cacheFromPool = peekCacheFromPool();
  if (cacheFromPool !== null) {
    return cacheFromPool;
  }

  // Create a fresh cache and add it to the root cache pool. A cache can have
  // multiple owners:
  // - A cache pool that lives on the FiberRoot. This is where all fresh caches
  //   are originally created (TODO: except during refreshes, until we implement
  //   this correctly). The root takes ownership immediately when the cache is
  //   created. Conceptually, root.pooledCache is an Option<Arc<Cache>> (owned),
  //   and the return value of this function is a &Arc<Cache> (borrowed).
  // - One of several fiber types: host root, cache boundary, suspense
  //   component. These retain and release in the commit phase.

  const root = (getWorkInProgressRoot(): any);
  const freshCache = createCache();
  root.pooledCache = freshCache;
  retainCache(freshCache);
  if (freshCache !== null) {
    root.pooledCacheLanes |= renderLanes;
  }
  return freshCache;
}

export function pushRootTransition(
  workInProgress: Fiber,