refactor: decouple node resolution from deno_core (#24724)

1 files changed, 53 insertions, 0 deletions

diff --git a/ext/node_resolver/package_json.rs b/ext/node_resolver/package_json.rs
new file mode 100644
index 000000000..de750f1d7
--- /dev/null
+++ b/ext/node_resolver/package_json.rs
@@ -0,0 +1,53 @@
+// Copyright 2018-2024 the Deno authors. All rights reserved. MIT license.
+
+use deno_package_json::PackageJson;
+use deno_package_json::PackageJsonRc;
+use std::cell::RefCell;
+use std::collections::HashMap;
+use std::io::ErrorKind;
+use std::path::Path;
+use std::path::PathBuf;
+
+use crate::errors::PackageJsonLoadError;
+
+// use a thread local cache so that workers have their own distinct cache
+thread_local! {
+  static CACHE: RefCell<HashMap<PathBuf, PackageJsonRc>> = RefCell::new(HashMap::new());
+}
+
+pub struct PackageJsonThreadLocalCache;
+
+impl PackageJsonThreadLocalCache {
+  pub fn clear() {
+    CACHE.with(|cache| cache.borrow_mut().clear());
+  }
+}
+
+impl deno_package_json::PackageJsonCache for PackageJsonThreadLocalCache {
+  fn get(&self, path: &Path) -> Option<PackageJsonRc> {
+    CACHE.with(|cache| cache.borrow().get(path).cloned())
+  }
+
+  fn set(&self, path: PathBuf, package_json: PackageJsonRc) {
+    CACHE.with(|cache| cache.borrow_mut().insert(path, package_json));
+  }
+}
+
+/// Helper to load a package.json file using the thread local cache
+/// in node_resolver.
+pub fn load_pkg_json(
+  fs: &dyn deno_package_json::fs::DenoPkgJsonFs,
+  path: &Path,
+) -> Result<Option<PackageJsonRc>, PackageJsonLoadError> {
+  let result =
+    PackageJson::load_from_path(path, fs, Some(&PackageJsonThreadLocalCache));
+  match result {
+    Ok(pkg_json) => Ok(Some(pkg_json)),
+    Err(deno_package_json::PackageJsonLoadError::Io { source, .. })
+      if source.kind() == ErrorKind::NotFound =>
+    {
+      Ok(None)
+    }
+    Err(err) => Err(PackageJsonLoadError(err)),
+  }
+}