perf(language_server): pass file content as a referenced String

crates/oxc_language_server/src/backend.rs

@@ -492,7 +492,7 @@ impl LanguageServer for Backend {
             self.file_system.write().await.set(uri, content.clone());
         }
 
-        if let Some(diagnostics) = worker.run_diagnostic_on_change(uri, content).await {
+        if let Some(diagnostics) = worker.run_diagnostic_on_change(uri, content.as_deref()).await {
             self.client
                 .publish_diagnostics(uri.clone(), diagnostics, Some(params.text_document.version))
                 .await;
@@ -516,7 +516,7 @@ impl LanguageServer for Backend {
             self.file_system.write().await.set(uri, content.clone());
         }
 
-        if let Some(diagnostics) = worker.run_diagnostic(uri, Some(content)).await {
+        if let Some(diagnostics) = worker.run_diagnostic(uri, Some(&content)).await {
             self.client
                 .publish_diagnostics(uri.clone(), diagnostics, Some(params.text_document.version))
                 .await;
@@ -599,7 +599,7 @@ impl LanguageServer for Backend {
         let Some(worker) = workers.iter().find(|worker| worker.is_responsible_for_uri(uri)) else {
             return Ok(None);
         };
-        Ok(worker.format_file(uri, self.file_system.read().await.get(uri)).await)
+        Ok(worker.format_file(uri, self.file_system.read().await.get(uri).as_deref()).await)
     }
 }
 

crates/oxc_language_server/src/formatter/server_formatter.rs

@@ -199,28 +199,34 @@ impl Tool for ServerFormatter {
         }
     }
 
-    fn run_format(&self, uri: &Uri, content: Option<String>) -> Option<Vec<TextEdit>> {
+    fn run_format(&self, uri: &Uri, content: Option<&str>) -> Option<Vec<TextEdit>> {
         // Formatter is disabled
         if !self.should_run {
             return None;
         }
 
         let path = uri.to_file_path()?;
         let source_type = get_supported_source_type(&path).map(enable_jsx_source_type)?;
+        // Declaring Variable to satisfy borrow checker
+        let file_content;
         let source_text = if let Some(content) = content {
             content
         } else {
             #[cfg(not(all(test, windows)))]
-            let source_text = std::fs::read_to_string(&path).ok()?;
+            {
+                file_content = std::fs::read_to_string(&path).ok()?;
+            }
             #[cfg(all(test, windows))]
             #[expect(clippy::disallowed_methods)] // no `cow_replace` in tests are fine
             // On Windows, convert CRLF to LF for consistent formatting results
-            let source_text = std::fs::read_to_string(&path).ok()?.replace("\r\n", "\n");
-            source_text
+            {
+                file_content = std::fs::read_to_string(&path).ok()?.replace("\r\n", "\n");
+            }
+            &file_content
         };
 
         let allocator = Allocator::new();
-        let ret = Parser::new(&allocator, &source_text, source_type)
+        let ret = Parser::new(&allocator, source_text, source_type)
             .with_options(get_parse_options())
             .parse();
 
@@ -231,14 +237,14 @@ impl Tool for ServerFormatter {
         let code = Formatter::new(&allocator, self.options.clone()).build(&ret.program);
 
         // nothing has changed
-        if code == source_text {
+        if code == *source_text {
             return Some(vec![]);
         }
 
-        let (start, end, replacement) = compute_minimal_text_edit(&source_text, &code);
-        let rope = Rope::from(source_text.as_str());
-        let (start_line, start_character) = get_line_column(&rope, start, &source_text);
-        let (end_line, end_character) = get_line_column(&rope, end, &source_text);
+        let (start, end, replacement) = compute_minimal_text_edit(source_text, &code);
+        let rope = Rope::from(source_text);
+        let (start_line, start_character) = get_line_column(&rope, start, source_text);
+        let (end_line, end_character) = get_line_column(&rope, end, source_text);
 
         Some(vec![TextEdit::new(
             Range::new(

crates/oxc_language_server/src/linter/isolated_lint_handler.rs

@@ -102,16 +102,17 @@ impl IsolatedLintHandler {
         Self { runner, unused_directives_severity: lint_options.report_unused_directive }
     }
 
-    pub fn run_single(&self, uri: &Uri, content: Option<String>) -> Option<Vec<DiagnosticReport>> {
+    pub fn run_single(&self, uri: &Uri, content: Option<&str>) -> Option<Vec<DiagnosticReport>> {
         let path = uri.to_file_path()?;
 
         if !Self::should_lint_path(&path) {
             return None;
         }
 
-        let source_text = content.or_else(|| read_to_string(&path).ok())?;
+        let source_text =
+            if let Some(content) = content { content } else { &read_to_string(&path).ok()? };
 
-        let mut diagnostics = self.lint_path(&path, uri, &source_text);
+        let mut diagnostics = self.lint_path(&path, uri, source_text);
         diagnostics.append(&mut generate_inverted_diagnostics(&diagnostics, uri));
         Some(diagnostics)
     }

crates/oxc_language_server/src/linter/server_linter.rs

@@ -455,7 +455,7 @@ impl Tool for ServerLinter {
     /// Lint a file with the current linter
     /// - If the file is not lintable or ignored, [`None`] is returned
     /// - If the file is lintable, but no diagnostics are found, an empty vector is returned
-    fn run_diagnostic(&self, uri: &Uri, content: Option<String>) -> Option<Vec<Diagnostic>> {
+    fn run_diagnostic(&self, uri: &Uri, content: Option<&str>) -> Option<Vec<Diagnostic>> {
         self.run_file(uri, content)
             .map(|reports| reports.into_iter().map(|report| report.diagnostic).collect())
     }
@@ -467,7 +467,7 @@ impl Tool for ServerLinter {
     fn run_diagnostic_on_change(
         &self,
         uri: &Uri,
-        content: Option<String>,
+        content: Option<&str>,
     ) -> Option<Vec<Diagnostic>> {
         if self.run != Run::OnType {
             return None;
@@ -479,11 +479,7 @@ impl Tool for ServerLinter {
     /// - If the file is not lintable or ignored, [`None`] is returned
     /// - If the linter is not set to `OnSave`, [`None`] is returned
     /// - If the file is lintable, but no diagnostics are found, an empty vector is returned
-    fn run_diagnostic_on_save(
-        &self,
-        uri: &Uri,
-        content: Option<String>,
-    ) -> Option<Vec<Diagnostic>> {
+    fn run_diagnostic_on_save(&self, uri: &Uri, content: Option<&str>) -> Option<Vec<Diagnostic>> {
         if self.run != Run::OnSave {
             return None;
         }
@@ -563,7 +559,7 @@ impl ServerLinter {
     }
 
     /// Lint a single file, return `None` if the file is ignored.
-    fn run_file(&self, uri: &Uri, content: Option<String>) -> Option<Vec<DiagnosticReport>> {
+    fn run_file(&self, uri: &Uri, content: Option<&str>) -> Option<Vec<DiagnosticReport>> {
         if self.is_ignored(uri) {
             return None;
         }

crates/oxc_language_server/src/tool.rs

@@ -69,15 +69,15 @@ pub trait Tool: Sized {
     /// Returns a vector of `TextEdit` representing the formatting changes.
     ///
     /// Not all tools will implement formatting, so the default implementation returns `None`.
-    fn run_format(&self, _uri: &Uri, _content: Option<String>) -> Option<Vec<TextEdit>> {
+    fn run_format(&self, _uri: &Uri, _content: Option<&str>) -> Option<Vec<TextEdit>> {
         None
     }
 
     /// Run diagnostics on the content of the given URI.
     /// If `content` is `None`, the tool should read the content from the file system.
     /// Returns a vector of `Diagnostic` representing the diagnostic results.
     /// Not all tools will implement diagnostics, so the default implementation returns `None`.
-    fn run_diagnostic(&self, _uri: &Uri, _content: Option<String>) -> Option<Vec<Diagnostic>> {
+    fn run_diagnostic(&self, _uri: &Uri, _content: Option<&str>) -> Option<Vec<Diagnostic>> {
         None
     }
 
@@ -88,7 +88,7 @@ pub trait Tool: Sized {
     fn run_diagnostic_on_save(
         &self,
         _uri: &Uri,
-        _content: Option<String>,
+        _content: Option<&str>,
     ) -> Option<Vec<Diagnostic>> {
         None
     }
@@ -100,7 +100,7 @@ pub trait Tool: Sized {
     fn run_diagnostic_on_change(
         &self,
         _uri: &Uri,
-        _content: Option<String>,
+        _content: Option<&str>,
     ) -> Option<Vec<Diagnostic>> {
         None
     }

crates/oxc_language_server/src/worker.rs

@@ -149,7 +149,7 @@ impl WorkspaceWorker {
     pub async fn run_diagnostic(
         &self,
         uri: &Uri,
-        content: Option<String>,
+        content: Option<&str>,
     ) -> Option<Vec<Diagnostic>> {
         let Some(server_linter) = &*self.server_linter.read().await else {
             return None;
@@ -162,7 +162,7 @@ impl WorkspaceWorker {
     pub async fn run_diagnostic_on_change(
         &self,
         uri: &Uri,
-        content: Option<String>,
+        content: Option<&str>,
     ) -> Option<Vec<Diagnostic>> {
         let Some(server_linter) = &*self.server_linter.read().await else {
             return None;
@@ -175,7 +175,7 @@ impl WorkspaceWorker {
     pub async fn run_diagnostic_on_save(
         &self,
         uri: &Uri,
-        content: Option<String>,
+        content: Option<&str>,
     ) -> Option<Vec<Diagnostic>> {
         let Some(server_linter) = &*self.server_linter.read().await else {
             return None;
@@ -187,7 +187,7 @@ impl WorkspaceWorker {
     /// Format a file with the current formatter
     /// - If no file is not formattable or ignored, [`None`] is returned
     /// - If the file is formattable, but no changes are made, an empty vector is returned
-    pub async fn format_file(&self, uri: &Uri, content: Option<String>) -> Option<Vec<TextEdit>> {
+    pub async fn format_file(&self, uri: &Uri, content: Option<&str>) -> Option<Vec<TextEdit>> {
         let Some(server_formatter) = &*self.server_formatter.read().await else {
             return None;
         };