perf: has_named_replacements

Author: SyMind

src/concat_source.rs

@@ -293,7 +293,7 @@ impl Stream for ConcatSourceStream<'_> {
     let mut current_line_offset = 0;
     let mut current_column_offset = 0;
     let mut source_mapping: HashMap<Cow<str>, u32> = HashMap::default();
-    let mut name_mapping: HashMap<Cow<str>, u32> = HashMap::default();
+    let mut name_mapping: HashMap<&str, u32> = HashMap::default();
     let mut need_to_close_mapping = false;
 
     let source_index_mapping: RefCell<LinearMap<u32>> =
@@ -411,7 +411,7 @@ impl Stream for ConcatSourceStream<'_> {
           let mut global_index = name_mapping.get(&name).copied();
           if global_index.is_none() {
             let len = name_mapping.len() as u32;
-            name_mapping.insert(name.clone(), len);
+            name_mapping.insert(name, len);
             on_name(len, name);
             global_index = Some(len);
           }

src/helpers.rs

@@ -118,7 +118,7 @@ pub type OnSource<'a, 'b> =
   &'a mut dyn FnMut(u32, Cow<'b, str>, Option<&'b Arc<str>>);
 
 /// [OnName] abstraction, see [webpack-sources onName](https://github.com/webpack/webpack-sources/blob/9f98066311d53a153fdc7c633422a1d086528027/lib/helpers/streamChunks.js#L13).
-pub type OnName<'a, 'b> = &'a mut dyn FnMut(u32, Cow<'b, str>);
+pub type OnName<'a, 'b> = &'a mut dyn FnMut(u32, &'b str);
 
 /// Callback invoked for each section during [`Stream::sections`], receiving the
 /// section's [`SectionOffset`] and an optional [`SourceMap`].
@@ -436,7 +436,7 @@ fn stream_chunks_of_source_map_final<'a>(
     )
   }
   for (i, name) in source_map.names().iter().enumerate() {
-    on_name(i as u32, Cow::Borrowed(name));
+    on_name(i as u32, name);
   }
   let mut mapping_active_line = 0;
   let mut on_mapping = |mapping: Mapping| {
@@ -499,7 +499,7 @@ fn stream_chunks_of_source_map_full<'a>(
     )
   }
   for (i, name) in source_map.names().iter().enumerate() {
-    on_name(i as u32, Cow::Borrowed(name));
+    on_name(i as u32, name);
   }
   let last_line = &lines[lines.len() - 1].line;
   let last_new_line = last_line.ends_with('\n');
@@ -780,12 +780,12 @@ pub fn stream_chunks_of_combined_source_map<'a>(
   let inner_source: RefCell<Option<&Arc<str>>> = RefCell::new(inner_source);
   let source_mapping: RefCell<HashMap<Cow<str>, u32>> =
     RefCell::new(HashMap::default());
-  let mut name_mapping: HashMap<Cow<str>, u32> = HashMap::default();
+  let mut name_mapping: HashMap<&str, u32> = HashMap::default();
   let source_index_mapping: RefCell<LinearMap<i64>> =
     RefCell::new(LinearMap::default());
   let name_index_mapping: RefCell<LinearMap<i64>> =
     RefCell::new(LinearMap::default());
-  let name_index_value_mapping: RefCell<LinearMap<Cow<str>>> =
+  let name_index_value_mapping: RefCell<LinearMap<&str>> =
     RefCell::new(LinearMap::default());
   let inner_source_index: RefCell<i64> = RefCell::new(-2);
   let inner_source_index_mapping: RefCell<LinearMap<i64>> =
@@ -799,7 +799,7 @@ pub fn stream_chunks_of_combined_source_map<'a>(
   > = RefCell::new(LinearMap::default());
   let inner_name_index_mapping: RefCell<LinearMap<i64>> =
     RefCell::new(LinearMap::default());
-  let inner_name_index_value_mapping: RefCell<LinearMap<Cow<str>>> =
+  let inner_name_index_value_mapping: RefCell<LinearMap<&str>> =
     RefCell::new(LinearMap::default());
   let inner_source_map_line_data: RefCell<Vec<SourceMapLineData>> =
     RefCell::new(Vec::new());
@@ -962,8 +962,8 @@ pub fn stream_chunks_of_combined_source_map<'a>(
                   let mut global_index = name_mapping.get(name).copied();
                   if global_index.is_none() {
                     let len = name_mapping.len() as u32;
-                    name_mapping.insert(name.clone(), len);
-                    on_name(len, name.clone());
+                    name_mapping.insert(name, len);
+                    on_name(len, name);
                     global_index = Some(len);
                   }
                   final_name_index = global_index.unwrap() as i64;
@@ -1019,8 +1019,8 @@ pub fn stream_chunks_of_combined_source_map<'a>(
                       let mut global_index = name_mapping.get(name).copied();
                       if global_index.is_none() {
                         let len = name_mapping.len() as u32;
-                        name_mapping.insert(name.clone(), len);
-                        on_name(len, name.clone());
+                        name_mapping.insert(name, len);
+                        on_name(len, name);
                         global_index = Some(len);
                       }
                       final_name_index = global_index.unwrap() as i64;
@@ -1119,8 +1119,8 @@ pub fn stream_chunks_of_combined_source_map<'a>(
           let mut global_index = name_mapping.get(name).copied();
           if global_index.is_none() {
             let len = name_mapping.len() as u32;
-            name_mapping.borrow_mut().insert(name.clone(), len);
-            on_name(len, name.clone());
+            name_mapping.borrow_mut().insert(name, len);
+            on_name(len, name);
             global_index = Some(len);
           }
           final_name_index = global_index.unwrap() as i64;

src/replace_source.rs

@@ -431,17 +431,20 @@ impl Stream for ReplaceSourceStream<'_> {
     on_name: crate::helpers::OnName<'_, 'a>,
   ) -> crate::helpers::GeneratedInfo {
     let on_name = RefCell::new(on_name);
-    let repls = &self.replacements;
+    let replacements = &self.replacements;
     let mut pos: u32 = 0;
     let mut i: usize = 0;
     let mut replacement_end: Option<u32> = None;
-    let mut next_replacement = (i < repls.len()).then(|| repls[i].start);
+    let mut next_replacement = (i < replacements.len()).then(|| replacements[i].start);
     let mut generated_line_offset: i64 = 0;
     let mut generated_column_offset: i64 = 0;
     let mut generated_column_offset_line = 0;
     let source_content_lines: RefCell<LinearMap<Option<SourceContent>>> =
       RefCell::new(LinearMap::default());
-    let name_mapping: RefCell<HashMap<Cow<str>, u32>> =
+
+    // if has named replacements, we need to map the name to the global name index
+    let has_named_replacements = replacements.iter().any(|repl| repl.name.is_some());
+    let name_mapping: RefCell<HashMap<&str, u32>> =
       RefCell::new(HashMap::default());
     let name_index_mapping: RefCell<LinearMap<u32>> =
       RefCell::new(LinearMap::default());
@@ -585,9 +588,13 @@ impl Stream for ReplaceSourceStream<'_> {
                     source_index: original.source_index,
                     original_line: original.original_line,
                     original_column: original.original_column,
-                    name_index: original.name_index.and_then(|name_index| {
-                      name_index_mapping.borrow().get(&name_index).copied()
-                    }),
+                    name_index: if !has_named_replacements {
+                      original.name_index
+                    } else {
+                      original.name_index.and_then(|name_index| {
+                        name_index_mapping.borrow().get(&name_index).copied()
+                      })
+                    },
                   }
                 }),
               },
@@ -612,7 +619,7 @@ impl Stream for ReplaceSourceStream<'_> {
           // Insert replacement content split into chunks by lines
           #[allow(unsafe_code)]
           // SAFETY: The safety of this operation relies on the fact that the `ReplaceSource` type will not delete the `replacements` during its entire lifetime.
-          let repl = &repls[i];
+          let repl = &replacements[i];
 
           let lines =
             split_into_lines(repl.content.as_str()).collect::<Vec<_>>();
@@ -627,8 +634,8 @@ impl Stream for ReplaceSourceStream<'_> {
             let mut global_index = name_mapping.get(name.as_str()).copied();
             if global_index.is_none() {
               let len = name_mapping.len() as u32;
-              name_mapping.insert(Cow::Borrowed(name), len);
-              on_name.borrow_mut()(len, Cow::Borrowed(name));
+              name_mapping.insert(name, len);
+              on_name.borrow_mut()(len, name);
               global_index = Some(len);
             }
             replacement_name_index = global_index;
@@ -683,8 +690,8 @@ impl Stream for ReplaceSourceStream<'_> {
 
           // Move to next replacement
           i += 1;
-          next_replacement = if i < repls.len() {
-            Some(repls[i].start)
+          next_replacement = if i < replacements.len() {
+            Some(replacements[i].start)
           } else {
             None
           };
@@ -792,24 +799,28 @@ impl Stream for ReplaceSourceStream<'_> {
         on_source(source_index, source, source_content);
       },
       &mut |name_index, name| {
-        let mut name_mapping = name_mapping.borrow_mut();
-        let mut global_index = name_mapping.get(&name).copied();
-        if global_index.is_none() {
-          let len = name_mapping.len() as u32;
-          name_mapping.insert(name.clone(), len);
-          on_name.borrow_mut()(len, name);
-          global_index = Some(len);
+        if !has_named_replacements {
+          on_name.borrow_mut()(name_index, name);
+        } else {
+          let mut name_mapping = name_mapping.borrow_mut();
+          let mut global_index = name_mapping.get(&name).copied();
+          if global_index.is_none() {
+            let len = name_mapping.len() as u32;
+            name_mapping.insert(name, len);
+            on_name.borrow_mut()(len, name);
+            global_index = Some(len);
+          }
+          name_index_mapping
+            .borrow_mut()
+            .insert(name_index, global_index.unwrap());
         }
-        name_index_mapping
-          .borrow_mut()
-          .insert(name_index, global_index.unwrap());
       },
     );
 
     // Handle remaining replacements one by one
     let mut line = result.generated_line as i64 + generated_line_offset;
-    while i < repls.len() {
-      let content = &repls[i].content;
+    while i < replacements.len() {
+      let content = &replacements[i].content;
       let lines: Vec<&str> = split_into_lines(content).collect();
 
       for (line_idx, content_line) in lines.iter().enumerate() {