perf: use arena with RwLock for package.json storage

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Co-Authored-By: Claude <[email protected]>

Author: Boshen

Cargo.lock

@@ -82,6 +82,7 @@ indexmap = { version = "2", features = ["serde"] }
 json-strip-comments = "3"
 once_cell = "1" # Use `std::sync::OnceLock::get_or_try_init` when it is stable.
 papaya = "0.2"
+parking_lot = "0.12"
 rustc-hash = { version = "2" }
 serde = { version = "1", features = ["derive"] } # derive for Deserialize from package.json
 serde_json = { version = "1", features = ["preserve_order"] } # preserve_order: package_json.exports requires order such as `["require", "import", "default"]`
@@ -152,8 +153,8 @@ rustdoc-args = ["--cfg", "docsrs"]
 opt-level = 3
 lto = "fat"
 codegen-units = 1
-strip = "symbols" # set to `false` for debug information
-debug = false # set to `true` for debug information
+strip = false # "symbols" # set to `false` for debug information
+debug = true # set to `true` for debug information
 panic = "abort" # Let it crash and force ourselves to write safe Rust.
 
 [profile.release.package.regex-automata]

Cargo.toml

@@ -7,6 +7,8 @@ use std::{
     sync::Arc,
 };
 
+use parking_lot::RwLock;
+
 use cfg_if::cfg_if;
 #[cfg(feature = "yarn_pnp")]
 use once_cell::sync::OnceCell;
@@ -22,11 +24,11 @@ use crate::{
 };
 
 /// Cache implementation used for caching filesystem access.
-#[derive(Default)]
 pub struct Cache<Fs> {
     pub(crate) fs: Fs,
     pub(crate) paths: HashSet<CachedPath, BuildHasherDefault<IdentityHasher>>,
     pub(crate) tsconfigs: HashMap<PathBuf, Arc<TsConfig>, BuildHasherDefault<FxHasher>>,
+    pub(crate) package_json_arena: RwLock<Vec<Arc<PackageJson>>>,
     #[cfg(feature = "yarn_pnp")]
     pub(crate) yarn_pnp_manifest: OnceCell<pnp::Manifest>,
 }
@@ -35,6 +37,7 @@ impl<Fs: FileSystem> Cache<Fs> {
     pub fn clear(&self) {
         self.paths.pin().clear();
         self.tsconfigs.pin().clear();
+        self.package_json_arena.write().clear();
     }
 
     #[allow(clippy::cast_possible_truncation)]
@@ -105,7 +108,7 @@ impl<Fs: FileSystem> Cache<Fs> {
         ctx: &mut Ctx,
     ) -> Result<Option<Arc<PackageJson>>, ResolveError> {
         // Change to `std::sync::OnceLock::get_or_try_init` when it is stable.
-        let result = path
+        let index_result = path
             .package_json
             .get_or_try_init(|| {
                 let package_json_path = path.path.join("package.json");
@@ -119,10 +122,35 @@ impl<Fs: FileSystem> Cache<Fs> {
                     package_json_path.clone()
                 };
                 PackageJson::parse(&self.fs, package_json_path, real_path, package_json_bytes)
-                    .map(|package_json| Some(Arc::new(package_json)))
+                    .map(|package_json| {
+                        let arc = Arc::new(package_json);
+                        // Acquire write lock to push to arena
+                        let mut arena = self.package_json_arena.write();
+                        let index = arena.len();
+                        arena.push(arc);
+                        Some(index)
+                    })
                     .map_err(ResolveError::Json)
-            })
-            .cloned();
+            });
+
+        // Lookup the Arc from the arena using the stored index
+        let result = index_result.and_then(|index_opt| {
+            match index_opt {
+                Some(index) => {
+                    // Get the Arc from the arena
+                    let arena = self.package_json_arena.read();
+                    arena.get(*index)
+                        .map(|arc| Ok(Some(Arc::clone(arc))))
+                        .unwrap_or_else(|| {
+                            // Index out of bounds (e.g., after cache clear)
+                            // Return None to indicate package.json not found
+                            Ok(None)
+                        })
+                }
+                None => Ok(None)
+            }
+        });
+
         // https://github.com/webpack/enhanced-resolve/blob/58464fc7cb56673c9aa849e68e6300239601e615/lib/DescriptionFileUtils.js#L68-L82
         match &result {
             Ok(Some(package_json)) => {
@@ -216,6 +244,7 @@ impl<Fs: FileSystem> Cache<Fs> {
                 .hasher(BuildHasherDefault::default())
                 .resize_mode(papaya::ResizeMode::Blocking)
                 .build(),
+            package_json_arena: RwLock::new(Vec::new()),
             #[cfg(feature = "yarn_pnp")]
             yarn_pnp_manifest: OnceCell::new(),
         }

src/cache/cache_impl.rs

@@ -29,7 +29,7 @@ pub struct CachedPathImpl {
     pub meta: OnceLock<Option<FileMetadata>>,
     pub canonicalized: OnceLock<Result<Weak<CachedPathImpl>, ResolveError>>,
     pub node_modules: OnceLock<Option<Weak<CachedPathImpl>>>,
-    pub package_json: OnceLock<Option<Arc<PackageJson>>>,
+    pub package_json: OnceLock<Option<usize>>,
     pub tsconfig: OnceLock<Option<Arc<TsConfig>>>,
 }