perf(rust): don't use regex on legitimize_identifier_name (#1477)

hyf0 · web-flow · commit 18bc6688b069 · 2024-06-29T00:09:08.000+08:00
diff --git a/crates/rolldown/src/ast_scanner/mod.rs b/crates/rolldown/src/ast_scanner/mod.rs
@@ -20,6 +20,7 @@ use rolldown_common::{
 use rolldown_error::BuildError;
 use rolldown_oxc_utils::{BindingIdentifierExt, BindingPatternExt};
 use rolldown_rstr::{Rstr, ToRstr};
+use rolldown_utils::ecma_script::legitimize_identifier_name;
 use rolldown_utils::path_ext::PathExt;
 use rustc_hash::FxHashMap;
 use std::sync::Arc;
@@ -260,6 +261,7 @@ impl<'me> AstScanner<'me> {
             .module_request
             .as_path()
             .representative_file_name();
+          let importee_repr = legitimize_identifier_name(&importee_repr);
           format!("{importee_repr}_default").into()
         } else {
           export_name.into()
diff --git a/crates/rolldown/src/module_loader/normal_module_task.rs b/crates/rolldown/src/module_loader/normal_module_task.rs
@@ -13,7 +13,7 @@ use rolldown_error::BuildError;
 use rolldown_oxc_utils::OxcAst;
 use rolldown_plugin::{HookResolveIdExtraOptions, SharedPluginDriver};
 use rolldown_resolver::ResolveError;
-use rolldown_utils::path_ext::PathExt;
+use rolldown_utils::{ecma_script::legitimize_identifier_name, path_ext::PathExt};
 use sugar_path::SugarPath;
 
 use super::{task_context::TaskContext, Msg};
@@ -246,6 +246,7 @@ impl NormalModuleTask {
     let (ast_scopes, mut ast_symbols) = make_ast_scopes_and_symbols(ast);
     let file_path: ResourceId = Arc::<str>::clone(&self.resolved_path.path).into();
     let repr_name = file_path.as_path().representative_file_name();
+    let repr_name = legitimize_identifier_name(&repr_name);
 
     let scanner = AstScanner::new(
       self.module_id,
diff --git a/crates/rolldown_utils/src/ecma_script.rs b/crates/rolldown_utils/src/ecma_script.rs
@@ -1,15 +1,45 @@
-use regex::Regex;
+use oxc::syntax::identifier;
 use std::borrow::Cow;
 
 pub fn is_validate_identifier_name(name: &str) -> bool {
   oxc::syntax::identifier::is_identifier_name(name)
 }
 
 pub fn legitimize_identifier_name(name: &str) -> Cow<str> {
-  static VALID_RE: once_cell::sync::Lazy<Regex> =
-    once_cell::sync::Lazy::new(|| Regex::new(r"[^a-zA-Z0-9_$]").unwrap());
+  let mut legitimized = String::new();
+  let mut have_seen_invalid_char = false;
 
-  VALID_RE.replace_all(name, "_")
+  let mut chars_indices = name.char_indices();
+
+  if let Some((_, first_char)) = chars_indices.next() {
+    if identifier::is_identifier_start(first_char) {
+      // Nothing we need to do
+    } else {
+      legitimized.push('_');
+      have_seen_invalid_char = true;
+    }
+  }
+
+  for (idx, char) in chars_indices {
+    if identifier::is_identifier_part(char) {
+      if have_seen_invalid_char {
+        legitimized.push(char);
+      }
+    } else {
+      if !have_seen_invalid_char {
+        // See a invalid char for the first time
+        have_seen_invalid_char = true;
+        legitimized.push_str(&name[..idx]);
+      }
+      legitimized.push('_');
+    }
+  }
+
+  if have_seen_invalid_char {
+    Cow::Owned(legitimized)
+  } else {
+    Cow::Borrowed(name)
+  }
 }
 
 #[test]
diff --git a/crates/rolldown_utils/src/path_ext.rs b/crates/rolldown_utils/src/path_ext.rs
@@ -2,8 +2,6 @@ use std::{borrow::Cow, ffi::OsStr, path::Path};
 
 use sugar_path::SugarPath;
 
-use crate::ecma_script::legitimize_identifier_name;
-
 pub trait PathExt {
   fn expect_to_str(&self) -> &str;
 
@@ -26,6 +24,7 @@ impl PathExt for std::path::Path {
       .into_owned()
   }
 
+  /// It doesn't ensure the file name is a valid identifier in JS.
   fn representative_file_name(&self) -> Cow<str> {
     let file_name =
       self.file_stem().map_or_else(|| self.to_string_lossy(), |stem| stem.to_string_lossy());
@@ -45,12 +44,7 @@ impl PathExt for std::path::Path {
       _ => file_name,
     };
 
-    let legal = legitimize_identifier_name(&file_name);
-    match legal {
-      // No changes. Just return the original file name.
-      Cow::Borrowed(_) => file_name,
-      Cow::Owned(v) => Cow::Owned(v),
-    }
+    file_name
   }
 }
 
