Make ChangedContent possibly borrow its contents to avoid unnecessary allocations

Author: zackradisic

crates/node/src/lib.rs

@@ -1,3 +1,4 @@
+use std::borrow::Cow;
 use std::ops::Deref;
 use std::sync::{atomic::AtomicBool, Mutex};
 
@@ -37,11 +38,11 @@ pub struct GlobEntry {
   pub pattern: String,
 }
 
-impl From<ChangedContent> for tailwindcss_oxide::ChangedContent {
+impl<'a> From<ChangedContent> for tailwindcss_oxide::ChangedContent<'a> {
   fn from(changed_content: ChangedContent) -> Self {
     Self {
-      file: changed_content.file.map(Into::into),
-      content: changed_content.content,
+      file: changed_content.file.map(Into::into).map(Cow::Owned),
+      content: changed_content.content.map(Cow::Owned),
     }
   }
 }
@@ -109,9 +110,13 @@ impl Scanner {
 
   #[napi]
   pub fn scan_files(&mut self, input: Vec<ChangedContent>) -> Vec<String> {
-    self
-      .scanner
-      .scan_content(input.into_iter().map(Into::into).collect())
+    self.scanner.scan_content(
+      input
+        .into_iter()
+        .map(Into::into)
+        .collect::<Vec<_>>()
+        .as_slice(),
+    )
   }
 
   #[napi]
@@ -224,8 +229,8 @@ pub fn tw_on_before_parse(handle: &mut OnBeforeParse) -> Result<()> {
 
   let mut scanner = tailwindcss_oxide::Scanner::new(None);
 
-  let candidates = scanner.scan_content(vec![tailwindcss_oxide::ChangedContent {
-    content: Some(source_code.to_string()),
+  let candidates = scanner.scan_content(&[tailwindcss_oxide::ChangedContent {
+    content: Some(source_code),
     file: None,
   }]);
 

crates/oxide/src/lib.rs

@@ -10,6 +10,7 @@ use glob_match::glob_match;
 use paths::Path;
 use rayon::prelude::*;
 use scanner::allowed_paths::read_dir;
+use std::borrow::Cow;
 use std::fs;
 use std::path::PathBuf;
 use std::sync;
@@ -40,9 +41,9 @@ fn init_tracing() {
 }
 
 #[derive(Debug, Clone)]
-pub struct ChangedContent {
-    pub file: Option<PathBuf>,
-    pub content: Option<String>,
+pub struct ChangedContent<'a> {
+    pub file: Option<Cow<'a, PathBuf>>,
+    pub content: Option<Cow<'a, str>>,
 }
 
 #[derive(Debug, Clone)]
@@ -111,7 +112,7 @@ impl Scanner {
     }
 
     #[tracing::instrument(skip_all)]
-    pub fn scan_content(&mut self, changed_content: Vec<ChangedContent>) -> Vec<String> {
+    pub fn scan_content<'a>(&mut self, changed_content: &[ChangedContent<'a>]) -> Vec<String> {
         self.prepare();
         let candidates = parse_all_blobs(read_all_files(changed_content));
 
@@ -128,13 +129,13 @@ impl Scanner {
     }
 
     #[tracing::instrument(skip_all)]
-    pub fn get_candidates_with_positions(
+    pub fn get_candidates_with_positions<'a>(
         &mut self,
-        changed_content: ChangedContent,
+        changed_content: ChangedContent<'a>,
     ) -> Vec<(String, usize)> {
         self.prepare();
 
-        let content = read_changed_content(changed_content).unwrap_or_default();
+        let content = read_changed_content(&changed_content).unwrap_or_default();
         let extractor = Extractor::with_positions(&content[..], Default::default());
 
         let candidates: Vec<(String, usize)> = extractor
@@ -198,14 +199,14 @@ impl Scanner {
 
             if should_scan_file {
                 changed_content.push(ChangedContent {
-                    file: Some(path.clone()),
+                    file: Some(Cow::Borrowed(path)),
                     content: None,
                 });
             }
         }
 
         if !changed_content.is_empty() {
-            let candidates = parse_all_blobs(read_all_files(changed_content));
+            let candidates = parse_all_blobs(read_all_files(changed_content.as_slice()));
             self.candidates.par_extend(candidates);
         }
     }
@@ -426,16 +427,16 @@ impl Scanner {
     }
 }
 
-fn read_changed_content(c: ChangedContent) -> Option<Vec<u8>> {
-    if let Some(content) = c.content {
-        return Some(content.into_bytes());
+fn read_changed_content<'a>(c: &ChangedContent<'a>) -> Option<Vec<u8>> {
+    if let Some(content) = &c.content {
+        return Some(content.as_bytes().to_vec());
     }
 
-    let Some(file) = c.file else {
+    let Some(file) = &c.file else {
         return Default::default();
     };
 
-    let Ok(content) = std::fs::read(&file).map_err(|e| {
+    let Ok(content) = std::fs::read(file.as_ref()).map_err(|e| {
         event!(tracing::Level::ERROR, "Failed to read file: {:?}", e);
         e
     }) else {
@@ -460,7 +461,7 @@ fn read_changed_content(c: ChangedContent) -> Option<Vec<u8>> {
 }
 
 #[tracing::instrument(skip_all)]
-fn read_all_files(changed_content: Vec<ChangedContent>) -> Vec<Vec<u8>> {
+fn read_all_files<'a>(changed_content: &[ChangedContent<'a>]) -> Vec<Vec<u8>> {
     event!(
         tracing::Level::INFO,
         "Reading {:?} file(s)",