From 949cbc2b185bbe0aa7a8d6429745265ee0f240ff Mon Sep 17 00:00:00 2001
From: tidely <43219534+tidely@users.noreply.github.com>
Date: Wed, 17 Dec 2025 09:56:05 +0200
Subject: [PATCH] gpui: Remove intermediate allocations when reconstructing
 text from a `TextLayout` (#45037)

Closes #ISSUE

Remove some intermediate allocations when reconstructing text or wrapped
text from a `TextLayout`. Currently creates a intermediate `Vec<String>`
which gets joined, when you could join an `impl Iterator<Item = &str>`

Release Notes:

- N/A *or* Added/Fixed/Improved ...
---
 crates/gpui/src/elements/text.rs | 18 +++++++++++-------
 crates/markdown/src/markdown.rs  |  9 ++++++---
 2 files changed, 17 insertions(+), 10 deletions(-)

diff --git a/crates/gpui/src/elements/text.rs b/crates/gpui/src/elements/text.rs
index 914e8a286510a2ffd833db4c4d3ef85c84db073f..1b1bfd778c7bc746c67551eb31cf70f60b1485ea 100644
--- a/crates/gpui/src/elements/text.rs
+++ b/crates/gpui/src/elements/text.rs
@@ -6,6 +6,7 @@ use crate::{
     register_tooltip_mouse_handlers, set_tooltip_on_window,
 };
 use anyhow::Context as _;
+use itertools::Itertools;
 use smallvec::SmallVec;
 use std::{
     borrow::Cow,
@@ -597,14 +598,14 @@ impl TextLayout {
             .unwrap()
             .lines
             .iter()
-            .map(|s| s.text.to_string())
-            .collect::<Vec<_>>()
+            .map(|s| &s.text)
             .join("\n")
     }
 
     /// The text for this layout (with soft-wraps as newlines)
     pub fn wrapped_text(&self) -> String {
-        let mut lines = Vec::new();
+        let mut accumulator = String::new();
+
         for wrapped in self.0.borrow().as_ref().unwrap().lines.iter() {
             let mut seen = 0;
             for boundary in wrapped.layout.wrap_boundaries.iter() {
@@ -612,13 +613,16 @@ impl TextLayout {
                     [boundary.glyph_ix]
                     .index;
 
-                lines.push(wrapped.text[seen..index].to_string());
+                accumulator.push_str(&wrapped.text[seen..index]);
+                accumulator.push('\n');
                 seen = index;
             }
-            lines.push(wrapped.text[seen..].to_string());
+            accumulator.push_str(&wrapped.text[seen..]);
+            accumulator.push('\n');
         }
-
-        lines.join("\n")
+        // Remove trailing newline
+        accumulator.pop();
+        accumulator
     }
 }
 
diff --git a/crates/markdown/src/markdown.rs b/crates/markdown/src/markdown.rs
index 536d9fd6a2439e9b23b9f99d20a4aff425eda956..3654418e419bb58f5c9c29ac1baf7172a423156f 100644
--- a/crates/markdown/src/markdown.rs
+++ b/crates/markdown/src/markdown.rs
@@ -1919,7 +1919,7 @@ impl RenderedText {
     }
 
     fn text_for_range(&self, range: Range<usize>) -> String {
-        let mut ret = vec![];
+        let mut accumulator = String::new();
 
         for line in self.lines.iter() {
             if range.start > line.source_end {
@@ -1944,9 +1944,12 @@ impl RenderedText {
             }
             .min(text.len());
 
-            ret.push(text[start..end].to_string());
+            accumulator.push_str(&text[start..end]);
+            accumulator.push('\n');
         }
-        ret.join("\n")
+        // Remove trailing newline
+        accumulator.pop();
+        accumulator
     }
 
     fn link_for_position(&self, position: Point<Pixels>) -> Option<&RenderedLink> {