perf(pnp): cache findApiPath lookup

yarnpkg · Jun 13, 2020 · 206b955 · 206b955
1 parent 3c904ab
commit 206b955
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Showing 3 changed files with 62 additions and 5 deletions.
diff --git a/.pnp.js b/.pnp.js
diff --git a/packages/yarnpkg-pnp/sources/hook.js b/packages/yarnpkg-pnp/sources/hook.js
diff --git a/packages/yarnpkg-pnp/sources/loader/makeManager.ts b/packages/yarnpkg-pnp/sources/loader/makeManager.ts
@@ -66,24 +66,49 @@ export function makeManager(pnpapi: PnpApi, opts: MakeManagerOptions) {
     return apiEntry;
   }
 
+  const findApiPathCache = new Map<PortablePath,PortablePath | null>();
+
+  function addToCache(start: PortablePath, end: PortablePath, target: PortablePath | null) {
+    let curr;
+    let next = start;
+
+    do {
+      curr = next;
+      findApiPathCache.set(curr, target);
+      next = ppath.dirname(curr);
+    } while (curr !== end);
+  }
+
   function findApiPathFor(modulePath: NativePath) {
     let curr: PortablePath;
     let next = ppath.resolve(npath.toPortablePath(modulePath));
+    const start = next;
 
     do {
       curr = next;
 
+      const cached = findApiPathCache.get(curr);
+      if (cached !== undefined) {
+        addToCache(start, curr, cached);
+        return cached;
+      }
+
       const candidate = ppath.join(curr, `.pnp.js` as Filename);
-      if (xfs.existsSync(candidate) && xfs.statSync(candidate).isFile())
+      if (xfs.existsSync(candidate) && xfs.statSync(candidate).isFile()) {
+        addToCache(start, curr, candidate);
         return candidate;
+      }
 
       const cjsCandidate = ppath.join(curr, `.pnp.cjs` as Filename);
-      if (xfs.existsSync(cjsCandidate) && xfs.statSync(cjsCandidate).isFile())
+      if (xfs.existsSync(cjsCandidate) && xfs.statSync(cjsCandidate).isFile()) {
+        addToCache(start, curr, cjsCandidate);
         return cjsCandidate;
+      }
 
       next = ppath.dirname(curr);
     } while (curr !== PortablePath.root);
 
+    addToCache(start, curr, null);
     return null;
   }