Introduce operator+= to simplify response creation.

src/server/internalServer.cpp

@@ -633,12 +633,13 @@ std::unique_ptr<Response> InternalServer::handle_search(const RequestContext& re
       // Searcher->search will throw a runtime error if there is no valid xapian database to do the search.
       // (in case of zim file not containing a index)
       const auto cssUrl = renderUrl(m_root, RESOURCE::templates::url_of_search_results_css);
-      return HTTPErrorHtmlResponse(*this, request, MHD_HTTP_NOT_FOUND,
-                                   "fulltext-search-unavailable",
-                                   "404-page-heading",
-                                   cssUrl)
-           + nonParameterizedMessage("no-search-results")
-           + TaskbarInfo(searchInfo.bookName, archive.get());
+      HTTPErrorHtmlResponse response(*this, request, MHD_HTTP_NOT_FOUND,
+                                     "fulltext-search-unavailable",
+                                     "404-page-heading",
+                                     cssUrl);
+      response += nonParameterizedMessage("no-search-results");
+      response += TaskbarInfo(searchInfo.bookName, archive.get());
+      return response;
     }
 
 

src/server/response.cpp

@@ -194,6 +194,12 @@ HTTPErrorHtmlResponse& HTTPErrorHtmlResponse::operator+(const ParameterizedMessa
   return *this + details.getText(m_request.get_user_language());
 }
 
+HTTPErrorHtmlResponse& HTTPErrorHtmlResponse::operator+=(const ParameterizedMessage& details)
+{
+  // operator+() is already a state-modifying operator (akin to operator+=)
+  return *this + details;
+}
+
 
 HTTP400HtmlResponse::HTTP400HtmlResponse(const InternalServer& server,
                                          const RequestContext& request)
@@ -246,6 +252,13 @@ ContentResponseBlueprint& ContentResponseBlueprint::operator+(const TaskbarInfo&
   return *this;
 }
 
+ContentResponseBlueprint& ContentResponseBlueprint::operator+=(const TaskbarInfo& taskbarInfo)
+{
+  // operator+() is already a state-modifying operator (akin to operator+=)
+  return *this + taskbarInfo;
+}
+
+
 std::unique_ptr<Response> Response::build_416(const InternalServer& server, size_t resourceLength)
 {
   auto response = Response::build(server);

src/server/response.h

@@ -165,6 +165,7 @@ public: // functions
 
 
   ContentResponseBlueprint& operator+(const TaskbarInfo& taskbarInfo);
+  ContentResponseBlueprint& operator+=(const TaskbarInfo& taskbarInfo);
 
 protected: // functions
   std::string getMessage(const std::string& msgId) const;
@@ -190,8 +191,10 @@ struct HTTPErrorHtmlResponse : ContentResponseBlueprint
                       const std::string& cssUrl = "");
 
   using ContentResponseBlueprint::operator+;
+  using ContentResponseBlueprint::operator+=;
   HTTPErrorHtmlResponse& operator+(const std::string& msg);
   HTTPErrorHtmlResponse& operator+(const ParameterizedMessage& errorDetails);
+  HTTPErrorHtmlResponse& operator+=(const ParameterizedMessage& errorDetails);
 };
 
 class UrlNotFoundMsg {};