container: root: rewrite throw handler, refactor using common types

- Refactor using common types that were once internal
- Removes ancient macro approaches to C++20 solutions
- Changes `Exception` message type to use std::string
  * std::string_view isn't worthwhile in this context

container/src/root/common/utility.hh

@@ -30,6 +30,8 @@
 #include <string>
 #include <vector>
 
+#include "./type.hh"
+
 //! \namespace dfi
 //! \since docker-finance 1.0.0
 namespace dfi
@@ -39,6 +41,51 @@ namespace dfi
 //! \since docker-finance 1.1.0
 namespace common
 {
+
+//! \concept Exception
+//! \brief Exception type concept for `dfi` exceptions
+//! \ingroup cpp_common_impl
+//! \since docker-finance 1.1.0
+template <typename t_exception>
+concept Exception = std::derived_from<t_exception, type::Exception>;
+
+//! \brief Throw exception using `dfi` exception type
+//! \param message Message to pass to exception type
+//! \param location Source location of exception
+//! \ingroup cpp_common_impl
+//! \since docker-finance 1.1.0
+template <Exception t_exception>
+inline void throw_ex(
+    const std::string& message = {},
+    const std::source_location location = std::source_location::current())
+{
+  // TODO(unassigned): when throwing because of heap allocation
+  std::string msg;
+  msg += std::string("     \n\tFILE = ") + location.file_name();
+  msg += std::string("     \n\tFUNC = ") + location.function_name();
+  msg += std::string("     \n\tLINE = ") + location.line();
+  msg += std::string("     \n\tWHAT = ") + message;
+  throw t_exception(msg);
+}
+
+//! \brief Throw exception using `dfi` exception type (but only on condition)
+//! \param condition If boolean condition is true, throw
+//! \param message Message to pass to exception type
+//! \param location Source location of exception
+//! \ingroup cpp_common_impl
+//! \since docker-finance 1.1.0
+template <Exception t_exception>
+inline void throw_ex_if(
+    const bool condition,
+    const std::string& message = {},
+    const std::source_location location = std::source_location::current())
+{
+  if (condition)
+    {
+      throw_ex<t_exception>(message, location);
+    }
+}
+
 //! \brief Wrapper to ROOT Cling commands
 //! \ingroup cpp_common_impl
 //! \since docker-finance 1.0.0
@@ -69,16 +116,13 @@ class Command
   static void load(const std::string& path)
   {
     std::filesystem::path p(path);
-    if (!std::filesystem::exists(p))
-      {
-        throw std::runtime_error(
-            std::string{"'" + path + "' does not exist!"}.c_str());
-      }
-    if (!std::filesystem::is_regular_file(p))
-      {
-        throw std::runtime_error(
-            std::string{"'" + path + "' is not a regular file!"}.c_str());
-      }
+
+    throw_ex_if<type::RuntimeError>(
+        !std::filesystem::exists(p), "'" + path + "' does not exist!");
+
+    throw_ex_if<type::RuntimeError>(
+        !std::filesystem::is_regular_file(p),
+        "'" + path + "' is not a regular file!");
 
     std::string cmd{".L " + path};
     Command::cmd_handler({cmd});
@@ -101,9 +145,10 @@ class Command
 std::string get_env(const std::string& var)
 {
   const auto* env = gSystem->Getenv(var.c_str());
-  if (!env)
-    throw std::runtime_error(
-        std::string{var + " is not set or is unavailable"}.c_str());
+
+  throw_ex_if<type::RuntimeError>(
+      !env, "'" + var + "' is not set or is unavailable");
+
   return std::string{env};
 }