From 06209f824cf398bcd3332dc37f2d22cbdd840647 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bartek=20Iwa=C5=84czuk?= <biwanczuk@gmail.com>
Date: Tue, 25 Jul 2023 23:43:00 +0200
Subject: perf: cache node resolution when accesing a global (#19930)

Reclaims some of the performance hit introduced by
https://github.com/denoland/deno/pull/19307.
---
 ext/node/resolution.rs | 25 ++++++++++++++++++++++++-
 1 file changed, 24 insertions(+), 1 deletion(-)

(limited to 'ext/node/resolution.rs')

diff --git a/ext/node/resolution.rs b/ext/node/resolution.rs
index 748506789..143edb6fe 100644
--- a/ext/node/resolution.rs
+++ b/ext/node/resolution.rs
@@ -1,5 +1,6 @@
 // Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
 
+use std::collections::HashMap;
 use std::path::Path;
 use std::path::PathBuf;
 
@@ -111,17 +112,39 @@ pub type NodeResolverRc = deno_fs::sync::MaybeArc<NodeResolver>;
 pub struct NodeResolver {
   fs: FileSystemRc,
   npm_resolver: NpmResolverRc,
+  in_npm_package_cache: deno_fs::sync::MaybeArcMutex<HashMap<String, bool>>,
 }
 
 impl NodeResolver {
   pub fn new(fs: FileSystemRc, npm_resolver: NpmResolverRc) -> Self {
-    Self { fs, npm_resolver }
+    Self {
+      fs,
+      npm_resolver,
+      in_npm_package_cache: deno_fs::sync::MaybeArcMutex::new(HashMap::new()),
+    }
   }
 
   pub fn in_npm_package(&self, specifier: &ModuleSpecifier) -> bool {
     self.npm_resolver.in_npm_package(specifier)
   }
 
+  pub fn in_npm_package_with_cache(&self, specifier: String) -> bool {
+    let mut cache = self.in_npm_package_cache.lock();
+
+    if let Some(result) = cache.get(&specifier) {
+      return *result;
+    }
+
+    let result =
+      if let Ok(specifier) = deno_core::ModuleSpecifier::parse(&specifier) {
+        self.npm_resolver.in_npm_package(&specifier)
+      } else {
+        false
+      };
+    cache.insert(specifier, result);
+    result
+  }
+
   /// This function is an implementation of `defaultResolve` in
   /// `lib/internal/modules/esm/resolve.js` from Node.
   pub fn resolve(
-- 
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