Finished refactoring sf-buffer

sf-buffer/src/WriterUtils.cpp

@@ -0,0 +1,49 @@
+#include <iostream>
+#include <unistd.h>
+
+#include "WriterUtils.hpp"
+#include "date.h"
+
+using namespace std;
+
+void WriterUtils::set_process_effective_id(int user_id)
+{
+
+    // TODO: use setfsuid and setfsgid
+
+    if (setegid(user_id)) {
+        stringstream err_msg;
+
+        using namespace date;
+        using namespace chrono;
+        err_msg << "[" << system_clock::now() << "]";
+        err_msg << "[WriterUtils::set_process_effective_id]";
+        err_msg << " Cannot set group_id to " << user_id << endl;
+
+        throw runtime_error(err_msg.str());
+    }
+
+    if (seteuid(user_id)) {
+        stringstream err_msg;
+
+        using namespace date;
+        using namespace chrono;
+        err_msg << "[" << system_clock::now() << "]";
+        err_msg << "[WriterUtils::set_process_effective_id]";
+        err_msg << " Cannot set user_id to " << user_id << endl;
+
+        throw runtime_error(err_msg.str());
+    }
+}
+
+void WriterUtils::create_destination_folder(const string& output_file)
+{
+    auto file_separator_index = output_file.rfind('/');
+
+    if (file_separator_index != string::npos) {
+        string output_folder(output_file.substr(0, file_separator_index));
+
+        string create_folder_command("mkdir -p " + output_folder);
+        system(create_folder_command.c_str());
+    }
+}