perf: rope iter

Author: SyMind

src/cached_source.rs

@@ -21,7 +21,7 @@ use crate::{
 struct CachedData {
   hash: OnceLock<u64>,
   size: OnceLock<usize>,
-  source: OnceLock<(Vec<&'static str>, usize)>,
+  source: OnceLock<Vec<&'static str>>,
   columns_map: OnceLock<Option<SourceMap>>,
   line_only_map: OnceLock<Option<SourceMap>>,
 }
@@ -84,25 +84,25 @@ impl CachedSource {
 
 impl Source for CachedSource {
   fn source(&self) -> SourceValue {
-    let (chunks, len) = self.cache.source.get_or_init(|| {
+    let chunks = self.cache.source.get_or_init(|| {
       #[allow(unsafe_code)]
       // SAFETY: CachedSource guarantees that the underlying source outlives the cache,
       // so transmuting Vec<&str> to Vec<&'static str> is safe in this context.
       // This allows us to store string slices in the cache without additional allocations.
       unsafe {
-        std::mem::transmute::<(Vec<&str>, usize), (Vec<&'static str>, usize)>(
-          self.rope(),
+        std::mem::transmute::<Vec<&str>, Vec<&'static str>>(
+          self.rope().collect(),
         )
       }
     });
-    let mut string = String::with_capacity(*len);
+    let mut string = String::with_capacity(self.size());
     for chunk in chunks {
       string.push_str(chunk);
     }
     SourceValue::String(Cow::Owned(string))
   }
 
-  fn rope(&self) -> (Vec<&str>, usize) {
+  fn rope(&self) -> Box<dyn Iterator<Item = &str> + '_> {
     self.inner.rope()
   }
 

src/concat_source.rs

@@ -175,19 +175,12 @@ impl Source for ConcatSource {
     }
   }
 
-  fn rope(&self) -> (Vec<&str>, usize) {
+  fn rope(&self) -> Box<dyn Iterator<Item = &str> + '_> {
     let children = self.optimized_children();
     if children.len() == 1 {
       children[0].rope()
     } else {
-      let mut merged_chunks = vec![];
-      let mut merged_len = 0;
-      for child in children {
-        let (chunks, len) = child.rope();
-        merged_chunks.extend(chunks);
-        merged_len += len;
-      }
-      (merged_chunks, merged_len)
+      Box::new(children.iter().flat_map(|child| child.rope()))
     }
   }
 

src/original_source.rs

@@ -56,8 +56,8 @@ impl Source for OriginalSource {
     SourceValue::String(Cow::Borrowed(&self.value))
   }
 
-  fn rope(&self) -> (Vec<&str>, usize) {
-    (vec![self.value.as_ref()], self.value.len())
+  fn rope(&self) -> Box<dyn Iterator<Item = &str> + '_> {
+    Box::new(std::iter::once(self.value.as_ref()))
   }
 
   fn buffer(&self) -> Cow<[u8]> {

src/raw_source.rs

@@ -64,8 +64,8 @@ impl Source for RawStringSource {
     SourceValue::String(Cow::Borrowed(&self.0))
   }
 
-  fn rope(&self) -> (Vec<&str>, usize) {
-    (vec![self.0.as_ref()], self.0.len())
+  fn rope(&self) -> Box<dyn Iterator<Item = &str> + '_> {
+    Box::new(std::iter::once(self.0.as_ref()))
   }
 
   fn buffer(&self) -> Cow<[u8]> {
@@ -214,9 +214,8 @@ impl Source for RawBufferSource {
     SourceValue::Buffer(Cow::Borrowed(&self.value))
   }
 
-  fn rope(&self) -> (Vec<&str>, usize) {
-    let s = self.get_or_init_value_as_string();
-    (vec![s], s.len())
+  fn rope(&self) -> Box<dyn Iterator<Item = &str> + '_> {
+    Box::new(std::iter::once(self.get_or_init_value_as_string()))
   }
 
   fn buffer(&self) -> Cow<[u8]> {