perf: avoid allocating new strings when no characters need to be escaped or removed

- Added fast-path check in `escape_chars` to detect early if escaping is needed.

- Added fast-path `contains` check in `replacements` to prevent regex deep cloning and unprintable chars removal when not needed.

Author: FranBarInstance

src/template.rs

@@ -407,13 +407,19 @@ impl<'a> Template<'a> {
     }
 
     fn replacements(&mut self) {
-        lazy_static::lazy_static! {
-            static ref RE: Regex = Regex::new(&format!(r"\s*{}", BACKSPACE)).expect("Failed to create regex with constant pattern");
+        if self.out.contains(BACKSPACE) {
+            lazy_static::lazy_static! {
+                static ref RE: Regex = Regex::new(&format!(r"\s*{}", BACKSPACE)).expect("Failed to create regex with constant pattern");
+            }
+            if let std::borrow::Cow::Owned(s) = RE.replace_all(&self.out, "") {
+                self.out = s;
+            }
         }
-        self.out = RE.replace_all(&self.out, "").to_string();
 
         // UNPRINTABLE should be substituted after BACKSPACE
-        self.out = self.out.replace(UNPRINTABLE, "");
+        if self.out.contains(UNPRINTABLE) {
+            self.out = self.out.replace(UNPRINTABLE, "");
+        }
     }
 
     /// Retrieves the status code.

src/utils.rs

@@ -596,6 +596,16 @@ pub fn find_tag_position(text: &str, tag: &str) -> Option<usize> {
 /// assert_eq!(escaped, r#"Hello, &lt;world&gt; &amp; &quot;friends&quot;! &#123;example&#125;"#);
 /// ```
 pub fn escape_chars(input: &str, escape_braces: bool) -> String {
+    let needs_escape = input.chars().any(|c| match c {
+        '&' | '<' | '>' | '"' | '\'' | '/' => true,
+        '{' | '}' if escape_braces => true,
+        _ => false,
+    });
+
+    if !needs_escape {
+        return input.to_string();
+    }
+
     let mut result = String::with_capacity(input.len() * 2);
 
     for c in input.chars() {