perf: using Arc<str> to share source content between source map

Cargo.toml

@@ -40,6 +40,7 @@ memchr = "2.7.4"
 codspeed-criterion-compat = { version = "2.7.2", default-features = false, optional = true }
 static_assertions = "1.1.0"
 simd-json = "0.14.3"
+self_cell = "1.2.1"
 
 [dev-dependencies]
 twox-hash = "2.1.0"

benches/bench.rs

@@ -62,7 +62,7 @@ fn benchmark_concat_generate_string(b: &mut Bencher) {
  value: HELLOWORLD_MIN_JS,
  name: "helloworld.min.js",
  source_map: SourceMap::from_json(HELLOWORLD_MIN_JS_MAP).unwrap(),
- original_source: Some(HELLOWORLD_JS.to_string()),
+ original_source: Some(HELLOWORLD_JS.to_string().into()),
  inner_source_map: Some(SourceMap::from_json(HELLOWORLD_JS_MAP).unwrap()),
  remove_original_source: false,
  });
@@ -92,7 +92,7 @@ fn benchmark_concat_generate_string_with_cache(b: &mut Bencher) {
  value: HELLOWORLD_MIN_JS,
  name: "helloworld.min.js",
  source_map: SourceMap::from_json(HELLOWORLD_MIN_JS_MAP).unwrap(),
- original_source: Some(HELLOWORLD_JS.to_string()),
+ original_source: Some(HELLOWORLD_JS.to_string().into()),
  inner_source_map: Some(SourceMap::from_json(HELLOWORLD_JS_MAP).unwrap()),
  remove_original_source: false,
  });
@@ -121,7 +121,7 @@ fn benchmark_cached_source_hash(b: &mut Bencher) {
  value: HELLOWORLD_MIN_JS,
  name: "helloworld.min.js",
  source_map: SourceMap::from_json(HELLOWORLD_MIN_JS_MAP).unwrap(),
- original_source: Some(HELLOWORLD_JS.to_string()),
+ original_source: Some(HELLOWORLD_JS.to_string().into()),
  inner_source_map: Some(SourceMap::from_json(HELLOWORLD_JS_MAP).unwrap()),
  remove_original_source: false,
  });

src/helpers.rs

@@ -3,6 +3,7 @@ use std::{
  cell::{OnceCell, RefCell},
  marker::PhantomData,
  ops::Range,
+ sync::Arc,
 };
 
 use rustc_hash::FxHashMap as HashMap;
@@ -12,21 +13,18 @@ use crate::{
  encoder::create_encoder,
  linear_map::LinearMap,
  source::{Mapping, OriginalLocation},
+ source_content_lines::SourceContentLines,
  with_indices::WithIndices,
  MapOptions, Rope, SourceMap,
 };
 
-// Adding this type because sourceContentLine not happy
-type InnerSourceContentLine<'a, 'b> =
- RefCell<LinearMap<OnceCell<Option<Vec<WithIndices<'a, Rope<'b>>>>>>>;
-
 pub fn get_map<'a, S: StreamChunks>(
  stream: &'a S,
  options: &'a MapOptions,
 ) -> Option<SourceMap> {
  let mut mappings_encoder = create_encoder(options.columns);
  let mut sources: Vec<String> = Vec::new();
- let mut sources_content: Vec<String> = Vec::new();
+ let mut sources_content: Vec<Arc<str>> = Vec::new();
  let mut names: Vec<String> = Vec::new();
 
  stream.stream_chunks(
@@ -47,9 +45,9 @@ pub fn get_map<'a, S: StreamChunks>(
  sources[source_index] = source.to_string();
  if let Some(source_content) = source_content {
  if sources_content.len() <= source_index {
- sources_content.resize(source_index + 1, "".to_string());
+ sources_content.resize(source_index + 1, "".into());
  }
- sources_content[source_index] = source_content.to_string();
+ sources_content[source_index] = source_content.clone();
  }
  },
  // on_name
@@ -82,8 +80,9 @@ pub trait StreamChunks {
 pub type OnChunk<'a, 'b> = &'a mut dyn FnMut(Option<Rope<'b>>, Mapping);
 
 /// [OnSource] abstraction, see [webpack-sources onSource](https://github.com/webpack/webpack-sources/blob/9f98066311d53a153fdc7c633422a1d086528027/lib/helpers/streamChunks.js#L13).
+///
 pub type OnSource<'a, 'b> =
- &'a mut dyn FnMut(u32, Cow<'b, str>, Option<Rope<'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>);
@@ -195,8 +194,6 @@ where
  }
 }
 
-const EMPTY_ROPE: Rope = Rope::new();
-
 /// Split the string with a needle, each string will contain the needle.
 ///
 /// Copied and modified from https://github.com/rust-lang/cargo/blob/30efe860c0e4adc1a6d7057ad223dc6e47d34edf/src/cargo/sources/registry/index.rs#L1048-L1072
@@ -371,7 +368,7 @@ where
  on_source(
  i as u32,
  get_source(source_map, source),
- source_map.get_source_content(i).map(Rope::from),
+ source_map.get_source_content(i),
  )
  }
  for (i, name) in source_map.names().iter().enumerate() {
@@ -435,7 +432,7 @@ where
  on_source(
  i as u32,
  get_source(source_map, source),
- source_map.get_source_content(i).map(Rope::from),
+ source_map.get_source_content(i),
  )
  }
  for (i, name) in source_map.names().iter().enumerate() {
@@ -585,7 +582,7 @@ where
  on_source(
  i as u32,
  get_source(source_map, source),
- source_map.get_source_content(i).map(Rope::from),
+ source_map.get_source_content(i),
  )
  }
  let final_line = if result.generated_column == 0 {
@@ -633,7 +630,7 @@ where
  on_source(
  i as u32,
  get_source(source_map, source),
- source_map.get_source_content(i).map(Rope::from),
+ source_map.get_source_content(i),
  )
  }
  let mut current_generated_line = 1;
@@ -706,14 +703,14 @@ struct SourceMapLineData<'a> {
 }
 
 type InnerSourceIndexValueMapping<'a> =
- LinearMap<(Cow<'a, str>, Option<Rope<'a>>)>;
+ LinearMap<(Cow<'a, str>, Option<&'a Arc<str>>)>;
 
 #[allow(clippy::too_many_arguments)]
 pub fn stream_chunks_of_combined_source_map<'a, S>(
  source: S,
  source_map: &'a SourceMap,
  inner_source_name: &'a str,
- inner_source: Option<Rope<'a>>,
+ inner_source: Option<&'a Arc<str>>,
  inner_source_map: &'a SourceMap,
  remove_inner_source: bool,
  on_chunk: OnChunk<'_, 'a>,
@@ -725,7 +722,7 @@ where
  S: SourceText<'a> + 'a,
 {
  let on_source = RefCell::new(on_source);
- let inner_source: RefCell<Option<Rope<'a>>> = RefCell::new(inner_source);
+ 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();
@@ -740,10 +737,11 @@ where
  RefCell::new(LinearMap::default());
  let inner_source_index_value_mapping: RefCell<InnerSourceIndexValueMapping> =
  RefCell::new(LinearMap::default());
- let inner_source_contents: RefCell<LinearMap<Option<Rope<'a>>>> =
- RefCell::new(LinearMap::default());
- let inner_source_content_lines: InnerSourceContentLine =
+ let inner_source_contents: RefCell<LinearMap<Option<Arc<str>>>> =
  RefCell::new(LinearMap::default());
+ let inner_source_content_lines: RefCell<
+ LinearMap<OnceCell<Option<SourceContentLines>>>,
+ > = 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>>> =
@@ -828,11 +826,9 @@ where
  Some(once_cell) => once_cell.get_or_init(|| {
  let inner_source_contents = inner_source_contents.borrow();
  match inner_source_contents.get(&inner_source_index) {
- Some(Some(source_content)) => Some(
- split_into_lines(source_content)
- .map(WithIndices::new)
- .collect(),
- ),
+ Some(Some(source_content)) => {
+ Some(SourceContentLines::from(source_content.clone()))
+ }
  _ => None,
  }
  }),
@@ -848,8 +844,9 @@ where
  });
  if let Some(original_chunk) = original_chunk {
  if original_chunk.len() <= inner_chunk.len()
- && inner_chunk.get_byte_slice(..original_chunk.len())
- == Some(original_chunk)
+ && inner_chunk
+ .get_byte_slice(..original_chunk.len())
+ .is_some_and(|slice| slice == original_chunk)
  {
  inner_original_column += location_in_chunk;
  inner_name_index = -1;
@@ -928,11 +925,9 @@ where
  Some(once_cell) => once_cell.get_or_init(|| {
  let inner_source_contents = inner_source_contents.borrow();
  match inner_source_contents.get(&inner_source_index) {
- Some(Some(source_content)) => Some(
- split_into_lines(source_content)
- .map(WithIndices::new)
- .collect(),
- ),
+ Some(Some(source_content)) => {
+ Some(SourceContentLines::from(source_content.clone()))
+ }
  _ => None,
  }
  }),
@@ -945,12 +940,12 @@ where
  name_index_value_mapping.get(&name_index).cloned().unwrap();
  let original_name = original_source_lines
  .get(inner_original_line as usize - 1)
- .map_or(EMPTY_ROPE, |i| {
+ .map_or("", |i| {
  let start = inner_original_column as usize;
  let end = start + name.len();
  i.substring(start, end)
  });
- if Rope::from(&name) == original_name {
+ if name == original_name {
  let mut name_index_mapping = name_index_mapping.borrow_mut();
  final_name_index =
  name_index_mapping.get(&name_index).copied().unwrap_or(-2);
@@ -1015,7 +1010,7 @@ where
  on_source.borrow_mut()(
  len,
  Cow::Borrowed(inner_source_name),
- inner_source.borrow().clone(),
+ *inner_source.borrow(),
  );
  global_index = Some(len);
  }
@@ -1089,13 +1084,13 @@ where
  *inner_source_index.borrow_mut() = i as i64;
  let mut inner_source = inner_source.borrow_mut();
  if let Some(inner_source) = inner_source.as_ref() {
- source_content = Some(inner_source.clone());
+ source_content = Some(inner_source);
  } else {
- *inner_source = source_content.clone();
+ *inner_source = source_content;
  }
  source_index_mapping.borrow_mut().insert(i, -2);
  stream_chunks_of_source_map(
- source_content.unwrap(),
+ source_content.unwrap().as_ref(),
  inner_source_map,
  &mut |chunk, mapping| {
  let mut inner_source_map_line_data =
@@ -1151,7 +1146,7 @@ where
  &mut |i, source, source_content| {
  inner_source_contents
  .borrow_mut()
- .insert(i, source_content.clone());
+ .insert(i, source_content.cloned());
  inner_source_content_lines
  .borrow_mut()
  .insert(i, Default::default());
@@ -1200,7 +1195,7 @@ pub fn stream_and_get_source_and_map<'a, S: StreamChunks>(
 ) -> (GeneratedInfo, Option<SourceMap>) {
  let mut mappings_encoder = create_encoder(options.columns);
  let mut sources: Vec<String> = Vec::new();
- let mut sources_content: Vec<String> = Vec::new();
+ let mut sources_content: Vec<Arc<str>> = Vec::new();
  let mut names: Vec<String> = Vec::new();
 
  let generated_info = input_source.stream_chunks(
@@ -1215,11 +1210,11 @@ pub fn stream_and_get_source_and_map<'a, S: StreamChunks>(
  sources.push("".into());
  }
  sources[source_index2] = source.to_string();
- if let Some(ref source_content) = source_content {
+ if let Some(source_content) = source_content {
  while sources_content.len() <= source_index2 {
  sources_content.push("".into());
  }
- sources_content[source_index2] = source_content.to_string();
+ sources_content[source_index2] = source_content.clone();
  }
  on_source(source_index, source, source_content);
  },

src/lib.rs

@@ -12,6 +12,7 @@ mod raw_source;
 mod replace_source;
 mod rope;
 mod source;
+mod source_content_lines;
 mod source_map_source;
 mod with_indices;
 

src/original_source.rs

@@ -1,6 +1,7 @@
 use std::{
  borrow::Cow,
  hash::{Hash, Hasher},
+ sync::Arc,
 };
 
 use crate::{
@@ -36,13 +37,13 @@ use crate::{
 /// ```
 #[derive(Clone, Eq)]
 pub struct OriginalSource {
- value: String,
+ value: Arc<str>,
  name: String,
 }
 
 impl OriginalSource {
  /// Create a [OriginalSource].
- pub fn new(value: impl Into<String>, name: impl Into<String>) -> Self {
+ pub fn new(value: impl Into<Arc<str>>, name: impl Into<String>) -> Self {
  Self {
  value: value.into(),
  name: name.into(),
@@ -56,7 +57,7 @@ impl Source for OriginalSource {
  }
 
  fn rope(&self) -> Rope<'_> {
- Rope::from(&self.value)
+ Rope::from(self.value.as_ref())
  }
 
  fn buffer(&self) -> Cow<[u8]> {
@@ -113,7 +114,7 @@ impl StreamChunks for OriginalSource {
  on_source: OnSource<'_, 'a>,
  _on_name: OnName,
  ) -> crate::helpers::GeneratedInfo {
- on_source(0, Cow::Borrowed(&self.name), Some(Rope::from(&self.value)));
+ on_source(0, Cow::Borrowed(&self.name), Some(&self.value));
  if options.columns {
  // With column info we need to read all lines and split them
  let mut line = 1;
@@ -200,7 +201,7 @@ impl StreamChunks for OriginalSource {
  // we need to split source by lines
  let mut line = 1;
  let mut last_line = None;
- for l in split_into_lines(&self.value.as_str()) {
+ for l in split_into_lines(&self.value.as_ref()) {
  on_chunk(
  (!options.final_source).then_some(l.into_rope()),
  Mapping {
@@ -250,13 +251,10 @@ mod tests {
  assert_eq!(result_text.into_string_lossy(), "Line1\n\nLine3\n");
  assert_eq!(result_map.sources(), &["file.js".to_string()]);
  assert_eq!(result_list_map.sources(), ["file.js".to_string()]);
- assert_eq!(
- result_map.sources_content(),
- ["Line1\n\nLine3\n".to_string()],
- );
+ assert_eq!(result_map.sources_content(), ["Line1\n\nLine3\n".into()],);
  assert_eq!(
  result_list_map.sources_content(),
- ["Line1\n\nLine3\n".to_string()],
+ ["Line1\n\nLine3\n".into()],
  );
  assert_eq!(result_map.mappings(), "AAAA;;AAEA");
  assert_eq!(result_list_map.mappings(), "AAAA;AACA;AACA");