Fix warnings - for range loop no copies, unsigned int always >= 0 (#2383)

Author: sjanel

lib/src/AccessLogger.cc

@@ -260,10 +260,7 @@ void AccessLogger::initAndStart(const Json::Value &config)
             asyncFileLogger_.setFileSizeLimit(sizeLimit);
         }
         auto maxFiles = config.get("max_files", 0).asUInt();
-        if (maxFiles >= 0)
-        {
-            asyncFileLogger_.setMaxFiles(maxFiles);
-        }
+        asyncFileLogger_.setMaxFiles(maxFiles);
     }
     drogon::app().registerPreSendingAdvice(
         [this](const drogon::HttpRequestPtr &req,

lib/src/HttpAppFrameworkImpl.cc

@@ -376,7 +376,7 @@ void HttpAppFrameworkImpl::addPlugin(
     Json::Value pluginConfig;
     pluginConfig["name"] = name;
     Json::Value deps(Json::arrayValue);
-    for (const auto dep : dependencies)
+    for (const auto &dep : dependencies)
     {
         deps.append(dep);
     }
@@ -391,7 +391,7 @@ void HttpAppFrameworkImpl::addPlugins(const Json::Value &configs)
     assert(!isRunning());
     assert(configs.isArray());
     auto &plugins = jsonRuntimeConfig_["plugins"];
-    for (const auto config : configs)
+    for (const auto &config : configs)
     {
         plugins.append(config);
     }