Enter TaskbarInfo

After this change it's time to say thank you and good-bye to
`withTaskbarInfo()`. But it will take a while.

src/server/internalServer.cpp

@@ -627,9 +627,9 @@ std::unique_ptr<Response> InternalServer::handle_random(const RequestContext& re
   }
 
   if (archive == nullptr) {
-    const std::string error_details = noSuchBookErrorMsg(bookName);
-    auto response = Response::build_404(*this, "", error_details);
-    return withTaskbarInfo(bookName, nullptr, std::move(response));
+    return HTTP404HtmlResponse(*this, request)
+           + noSuchBookErrorMsg(bookName)
+           + TaskbarInfo(bookName);
   }
 
   try {

src/server/response.cpp

@@ -136,6 +136,20 @@ HTTP404HtmlResponse& HTTP404HtmlResponse::operator+(const std::string& msg)
   return *this;
 }
 
+HTTP404HtmlResponse& HTTP404HtmlResponse::operator+(const TaskbarInfo& taskbarInfo)
+{
+  this->taskbarInfo.reset(new TaskbarInfo(taskbarInfo));
+  return *this;
+}
+
+std::unique_ptr<ContentResponse> HTTP404HtmlResponse::generateResponseObject() const
+{
+  auto r = ContentResponseBlueprint::generateResponseObject();
+  return taskbarInfo
+       ? withTaskbarInfo(taskbarInfo->bookName, taskbarInfo->archive, std::move(r))
+       : std::move(r);
+}
+
 std::unique_ptr<Response> Response::build_416(const InternalServer& server, size_t resourceLength)
 {
   auto response = Response::build(server);

src/server/response.h

@@ -148,6 +148,8 @@ public: // functions
     , m_template(templateStr)
   {}
 
+  virtual ~ContentResponseBlueprint() = default;
+
   ContentResponseBlueprint& operator+(kainjow::mustache::data&& data)
   {
     this->m_data = std::move(data);
@@ -155,6 +157,11 @@ public: // functions
   }
 
   operator std::unique_ptr<ContentResponse>() const
+  {
+    return generateResponseObject();
+  }
+
+  virtual std::unique_ptr<ContentResponse> generateResponseObject() const
   {
     auto r = ContentResponse::build(m_server, m_template, m_data, m_mimeType);
     r->set_code(m_httpStatusCode);
@@ -179,6 +186,17 @@ class UrlNotFoundMsg {};
 
 extern const UrlNotFoundMsg urlNotFoundMsg;
 
+struct TaskbarInfo
+{
+  const std::string bookName;
+  const zim::Archive* const archive;
+
+  TaskbarInfo(const std::string& bookName, const zim::Archive* a = nullptr)
+    : bookName(bookName)
+    , archive(a)
+  {}
+};
+
 struct HTTP404HtmlResponse : ContentResponseBlueprint
 {
   HTTP404HtmlResponse(const InternalServer& server,
@@ -186,6 +204,11 @@ struct HTTP404HtmlResponse : ContentResponseBlueprint
 
   HTTP404HtmlResponse& operator+(UrlNotFoundMsg /*unused*/);
   HTTP404HtmlResponse& operator+(const std::string& errorDetails);
+  HTTP404HtmlResponse& operator+(const TaskbarInfo& taskbarInfo);
+
+  std::unique_ptr<ContentResponse> generateResponseObject() const override;
+
+  std::unique_ptr<TaskbarInfo> taskbarInfo;
 };
 
 class ItemResponse : public Response {