perf: cached fs utils with shared trees

packages/vite/src/node/fsUtils.ts

@@ -3,13 +3,16 @@ import path from 'node:path'
 import type { FSWatcher } from 'dep-types/chokidar'
 import type { ResolvedConfig } from './config'
 import {
+ createDebugger,
  isInNodeModules,
  normalizePath,
  safeRealpathSync,
  tryStatSync,
 } from './utils'
 import { searchForWorkspaceRoot } from './server/searchRoot'
 
+const debug = createDebugger('vite:fs')
+
 export interface FsUtils {
  existsSync: (path: string) => boolean
  isDirectory: (path: string) => boolean
@@ -41,10 +44,24 @@ export const commonFsUtils: FsUtils = {
  tryResolveRealFileOrType,
 }
 
+const activeResolvedConfigs = new Array<WeakRef<ResolvedConfig>>()
+const registry = new FinalizationRegistry((fsUtils: FsUtils) => {
+ const i = activeResolvedConfigs.findIndex((r) => !r.deref())
+ activeResolvedConfigs.splice(i, 1)
+})
+function addActiveResolvedConfig(config: ResolvedConfig, fsUtils: FsUtils) {
+ activeResolvedConfigs.push(new WeakRef(config))
+ registry.register(config, fsUtils)
+ debug?.(
+ `registered FsUtils for config with root ${config.root}, active configs: ${activeResolvedConfigs.length}`,
+ )
+}
+
 const cachedFsUtilsMap = new WeakMap<ResolvedConfig, FsUtils>()
 export function getFsUtils(config: ResolvedConfig): FsUtils {
  let fsUtils = cachedFsUtilsMap.get(config)
  if (!fsUtils) {
+ debug?.(`resolving FsUtils for ${config.root}`)
  if (config.command !== 'serve' || !config.server.fs.cachedChecks) {
  // cached fsUtils is only used in the dev server for now, and only when the watcher isn't configured
  // we can support custom ignored patterns later
@@ -56,6 +73,7 @@ export function getFsUtils(config: ResolvedConfig): FsUtils {
  fsUtils = commonFsUtils
  } else {
  fsUtils = createCachedFsUtils(config)
+ addActiveResolvedConfig(config, fsUtils)
  }
  cachedFsUtilsMap.set(config, fsUtils)
  }
@@ -118,16 +136,41 @@ function ensureFileMaybeSymlinkIsResolved(
  isSymlink === undefined ? 'error' : isSymlink ? 'symlink' : 'file'
 }
 
+interface CachedFsUtilsMeta {
+ root: string
+ rootCache: DirentCache
+}
+const cachedFsUtilsMeta = new WeakMap<ResolvedConfig, CachedFsUtilsMeta>()
+
+function createSharedRootCache(root: string): DirentCache {
+ for (const otherConfigRef of activeResolvedConfigs) {
+ const otherConfig = otherConfigRef?.deref()
+ if (otherConfig) {
+ const otherCachedFsUtilsMeta = cachedFsUtilsMeta.get(otherConfig)!
+ const { rootCache: otherRootCache, root: otherRoot } =
+ otherCachedFsUtilsMeta
+ if (root === otherRoot) {
+ debug?.(`FsUtils for ${root} sharing root cache with compatible cache`)
+ return otherRootCache
+ }
+ }
+ }
+
+ debug?.(`FsUtils for ${root} started as an new root cache`)
+ return { type: 'directory' as DirentCacheType } // dirents will be computed lazily
+}
+
 function pathUntilPart(root: string, parts: string[], i: number): string {
  let p = root
  for (let k = 0; k < i; k++) p += '/' + parts[k]
  return p
 }
 
-export function createCachedFsUtils(config: ResolvedConfig): FsUtils {
+function createCachedFsUtils(config: ResolvedConfig): FsUtils {
  const root = normalizePath(searchForWorkspaceRoot(config.root))
  const rootDirPath = `${root}/`
- const rootCache: DirentCache = { type: 'directory' } // dirents will be computed lazily
+ const rootCache = createSharedRootCache(root)
+ cachedFsUtilsMeta.set(config, { root, rootCache })
 
  const getDirentCacheSync = (parts: string[]): DirentCache | undefined => {
  let direntCache: DirentCache = rootCache
@@ -210,7 +253,10 @@ export function createCachedFsUtils(config: ResolvedConfig): FsUtils {
  direntCache.type === 'directory' &&
  direntCache.dirents
  ) {
- direntCache.dirents.set(path.basename(file), { type })
+ const fileBasename = path.basename(file)
+ if (!direntCache.dirents.has(fileBasename)) {
+ direntCache.dirents.set(fileBasename, { type })
+ }
  }
  }