webserver: string optimization (#7446)

* webserver: string optimization

* fix

Author: d-a-v

libraries/ESP8266WebServer/src/detail/RequestHandlersImpl.h

@@ -95,29 +95,31 @@ class StaticRequestHandler : public RequestHandler<ServerType> {
         return true;
     }
 
-    bool handle(WebServerType& server, HTTPMethod requestMethod, const String& __requestUri) override {
-        String requestUri(__requestUri);
+    bool handle(WebServerType& server, HTTPMethod requestMethod, const String& requestUri) override {
 
         if (!canHandle(requestMethod, requestUri))
             return false;
 
         DEBUGV("StaticRequestHandler::handle: request=%s _uri=%s\r\n", requestUri.c_str(), _uri.c_str());
 
-        String path(_path);
+        String path;
+        path.reserve(_path.length() + requestUri.length() + 32);
+        path = _path;
 
         if (!_isFile) {
-            // Base URI doesn't point to a file.
-            // If a directory is requested, look for index file.
-            if (requestUri.endsWith("/"))
-              requestUri += "index.htm";
 
             // Append whatever follows this URI in request to get the file path.
             path += requestUri.substring(_baseUriLength);
 
+            // Base URI doesn't point to a file.
+            // If a directory is requested, look for index file.
+            if (path.endsWith("/"))
+                path += F("index.htm");
+
             // If neither <blah> nor <blah>.gz exist, and <blah> is a file.htm, try it with file.html instead
             // For the normal case this will give a search order of index.htm, index.htm.gz, index.html, index.html.gz
             if (!_fs.exists(path) && !_fs.exists(path + ".gz") && path.endsWith(".htm")) {
-                path += "l";
+                path += 'l';
             }
         }
         DEBUGV("StaticRequestHandler::handle: path=%s, isFile=%d\r\n", path.c_str(), _isFile);