Stop collecting highlight_iter events then turning back into iter

helix-term/src/ui/editor.rs

@@ -139,31 +139,34 @@ impl EditorView {
             start..end
         };
 
-        // TODO: range doesn't actually restrict source, just highlight range
+        match doc.syntax() {
-        let highlights = match doc.syntax() {
             Some(syntax) => {
-                syntax
+                let iter = syntax
+                    // TODO: range doesn't actually restrict source, just highlight range
                     .highlight_iter(text.slice(..), Some(range), None)
                     .map(|event| event.unwrap())
-                    .collect() // TODO: we collect here to avoid holding the lock, fix later
+                    .map(move |event| match event {
+                        // convert byte offsets to char offset
+                        HighlightEvent::Source { start, end } => {
+                            let start =
+                                text.byte_to_char(ensure_grapheme_boundary_next_byte(text, start));
+                            let end =
+                                text.byte_to_char(ensure_grapheme_boundary_next_byte(text, end));
+                            HighlightEvent::Source { start, end }
+                        }
+                        event => event,
+                    });
+
+                Box::new(iter)
             }
-            None => vec![HighlightEvent::Source {
+            None => Box::new(
-                start: range.start,
+                [HighlightEvent::Source {
-                end: range.end,
+                    start: text.byte_to_char(range.start),
-            }],
+                    end: text.byte_to_char(range.end),
+                }]
+                .into_iter(),
+            ),
         }
-        .into_iter()
-        .map(move |event| match event {
-            // convert byte offsets to char offset
-            HighlightEvent::Source { start, end } => {
-                let start = text.byte_to_char(ensure_grapheme_boundary_next_byte(text, start));
-                let end = text.byte_to_char(ensure_grapheme_boundary_next_byte(text, end));
-                HighlightEvent::Source { start, end }
-            }
-            event => event,
-        });
-
-        Box::new(highlights)
     }
 
     /// Get highlight spans for document diagnostics