glib: Optimize IntoGStr impl for String by simply appending a NUL-byte

Author: sdroege

glib/src/gstring.rs

@@ -2317,12 +2317,10 @@ impl IntoGStr for &str {
 
 impl IntoGStr for String {
     #[inline]
-    fn run_with_gstr<T, F: FnOnce(&GStr) -> T>(self, f: F) -> T {
-        if self.len() < MAX_STACK_ALLOCATION {
-            self.as_str().run_with_gstr(f)
-        } else {
-            f(GString::from(self).as_gstr())
-        }
+    fn run_with_gstr<T, F: FnOnce(&GStr) -> T>(mut self, f: F) -> T {
+        self.push('\0');
+        let gs = unsafe { GStr::from_utf8_with_nul_unchecked(self.as_bytes()) };
+        f(gs)
     }
 }