Pass String by const reference [3.0] (#6583)

Passing String by value means a full copy-constructor/temporary
string creation which is slightly inefficient. Avoid that
by using const references.

Author: dirkmueller

Diff for: libraries/ESP8266WebServer/src/detail/RequestHandler.h

@@ -10,10 +10,10 @@ class RequestHandler {
     using WebServerType = ESP8266WebServerTemplate<ServerType>;
 public:
     virtual ~RequestHandler() { }
-    virtual bool canHandle(HTTPMethod method, String uri) { (void) method; (void) uri; return false; }
-    virtual bool canUpload(String uri) { (void) uri; return false; }
-    virtual bool handle(WebServerType& server, HTTPMethod requestMethod, String requestUri) { (void) server; (void) requestMethod; (void) requestUri; return false; }
-    virtual void upload(WebServerType& server, String requestUri, HTTPUpload& upload) { (void) server; (void) requestUri; (void) upload; }
+    virtual bool canHandle(HTTPMethod method, const String& uri) { (void) method; (void) uri; return false; }
+    virtual bool canUpload(const String& uri) { (void) uri; return false; }
+    virtual bool handle(WebServerType& server, HTTPMethod requestMethod, const String& requestUri) { (void) server; (void) requestMethod; (void) requestUri; return false; }
+    virtual void upload(WebServerType& server, const String& requestUri, HTTPUpload& upload) { (void) server; (void) requestUri; (void) upload; }
 
     RequestHandler<ServerType>* next() { return _next; }
     void next(RequestHandler<ServerType>* r) { _next = r; }

Diff for: libraries/ESP8266WebServer/src/detail/RequestHandlersImpl.h

@@ -25,21 +25,21 @@ class FunctionRequestHandler : public RequestHandler<ServerType> {
         delete _uri;
     }
 
-    bool canHandle(HTTPMethod requestMethod, String requestUri) override  {
+    bool canHandle(HTTPMethod requestMethod, const String& requestUri) override  {
         if (_method != HTTP_ANY && _method != requestMethod)
             return false;
 
         return _uri->canHandle(requestUri, RequestHandler<ServerType>::pathArgs);
     }
 
-    bool canUpload(String requestUri) override  {
+    bool canUpload(const String& requestUri) override  {
         if (!_ufn || !canHandle(HTTP_POST, requestUri))
             return false;
 
         return true;
     }
 
-    bool handle(WebServerType& server, HTTPMethod requestMethod, String requestUri) override {
+    bool handle(WebServerType& server, HTTPMethod requestMethod, const String& requestUri) override {
         (void) server;
         if (!canHandle(requestMethod, requestUri))
             return false;
@@ -48,7 +48,7 @@ class FunctionRequestHandler : public RequestHandler<ServerType> {
         return true;
     }
 
-    void upload(WebServerType& server, String requestUri, HTTPUpload& upload) override {
+    void upload(WebServerType& server, const String& requestUri, HTTPUpload& upload) override {
         (void) server;
         (void) upload;
         if (canUpload(requestUri))
@@ -85,7 +85,7 @@ class StaticRequestHandler : public RequestHandler<ServerType> {
         _baseUriLength = _uri.length();
     }
 
-    bool canHandle(HTTPMethod requestMethod, String requestUri) override  {
+    bool canHandle(HTTPMethod requestMethod, const String& requestUri) override  {
         if ((requestMethod != HTTP_GET) && (requestMethod != HTTP_HEAD))
             return false;
 
@@ -95,7 +95,9 @@ class StaticRequestHandler : public RequestHandler<ServerType> {
         return true;
     }
 
-    bool handle(WebServerType& server, HTTPMethod requestMethod, String requestUri) override {
+    bool handle(WebServerType& server, HTTPMethod requestMethod, const String& __requestUri) override {
+        String requestUri(__requestUri);
+
         if (!canHandle(requestMethod, requestUri))
             return false;