AK: Add fast path in String::trim() and String::trim_whitespace()

If the trimmed string would be the entire string, just return *this
instead of creating a new StringImpl.

1 files changed, 8 insertions, 2 deletions

diff --git a/AK/String.h b/AK/String.h
index 9f7988dcdc..27f7799fa7 100644
--- a/AK/String.h
+++ b/AK/String.h
@@ -127,12 +127,18 @@ public:
 #ifndef KERNEL
     [[nodiscard]] String trim(StringView characters, TrimMode mode = TrimMode::Both) const
     {
-        return StringUtils::trim(view(), characters, mode);
+        auto trimmed_view = StringUtils::trim(view(), characters, mode);
+        if (view() == trimmed_view)
+            return *this;
+        return trimmed_view;
     }
 
     [[nodiscard]] String trim_whitespace(TrimMode mode = TrimMode::Both) const
     {
-        return StringUtils::trim_whitespace(view(), mode);
+        auto trimmed_view = StringUtils::trim_whitespace(view(), mode);
+        if (view() == trimmed_view)
+            return *this;
+        return trimmed_view;
     }
 #endif