commit 8bff414abcd2ab8c3487085bb58cd5b8bea5436a
author Chayim Refael Friedman <chayimfr@gmail.com> Fri Apr 25 17:18:14 2025 +0300
committer Chayim Refael Friedman <chayimfr@gmail.com> Fri Apr 25 17:18:14 2025 +0300
tree 789fd153df2d719ac8ec4f735a25a32539ad105b
parent 5ff4ba347d7d5c7d063070872e9c5e581715f98f

Preallocate `parser::Input`

crates/parser/src/input.rs

diff --git a/crates/parser/src/input.rs b/crates/parser/src/input.rs
index cabdff2..4490956 100644
--- a/crates/parser/src/input.rs
+++ b/crates/parser/src/input.rs
@@ -12,7 +12,6 @@
 /// `Tokens` doesn't include whitespace and comments. Main input to the parser.
 ///
 /// Struct of arrays internally, but this shouldn't really matter.
-#[derive(Default)]
 pub struct Input {
     kind: Vec<SyntaxKind>,
     joint: Vec<bits>,
@@ -22,6 +21,14 @@
 /// `pub` impl used by callers to create `Tokens`.
 impl Input {
     #[inline]
+    pub fn with_capacity(capacity: usize) -> Self {
+        Self {
+            kind: Vec::with_capacity(capacity),
+            joint: Vec::with_capacity(capacity / size_of::<bits>()),
+            contextual_kind: Vec::with_capacity(capacity),
+        }
+    }
+    #[inline]
     pub fn push(&mut self, kind: SyntaxKind) {
         self.push_impl(kind, SyntaxKind::EOF)
     }

crates/parser/src/shortcuts.rs

diff --git a/crates/parser/src/shortcuts.rs b/crates/parser/src/shortcuts.rs
index 32569d5..e2baec8 100644
--- a/crates/parser/src/shortcuts.rs
+++ b/crates/parser/src/shortcuts.rs
@@ -27,7 +27,7 @@
 impl LexedStr<'_> {
     pub fn to_input(&self, edition: Edition) -> crate::Input {
         let _p = tracing::info_span!("LexedStr::to_input").entered();
-        let mut res = crate::Input::default();
+        let mut res = crate::Input::with_capacity(self.len());
         let mut was_joint = false;
         for i in 0..self.len() {
             let kind = self.kind(i);

crates/syntax-bridge/src/to_parser_input.rs

diff --git a/crates/syntax-bridge/src/to_parser_input.rs b/crates/syntax-bridge/src/to_parser_input.rs
index 0dcb2be..021dc65 100644
--- a/crates/syntax-bridge/src/to_parser_input.rs
+++ b/crates/syntax-bridge/src/to_parser_input.rs
@@ -12,7 +12,7 @@
     buffer: tt::TokenTreesView<'_, SpanData<Ctx>>,
     span_to_edition: &mut dyn FnMut(Ctx) -> Edition,
 ) -> parser::Input {
-    let mut res = parser::Input::default();
+    let mut res = parser::Input::with_capacity(buffer.len());
 
     let mut current = buffer.cursor();
     let mut syntax_context_to_edition_cache = FxHashMap::default();