Remove STL from source_location.hpp

Author: nickclark2016

projects/core/include/tempest/source_location.hpp

@@ -3,7 +3,61 @@
 
 #include <tempest/int.hpp>
 
-#include <source_location>
+// Check for GLIBCXX or LIBCPP
+#if ((defined(__GLIBCXX__) && !defined(_GLIBCXX_SRCLOC)) ||                                                            \
+     (defined(_LIBCPP_VERSION) && !defined(_LIBCPP_SOURCE_LOCATION))) &&                                               \
+    (defined(__GNUC__) || defined(__clang__))
+
+// Known UB. If libstdc++ or libc++ changes the layout of std::source_location::__impl, this will break
+// TODO: Investigate a robust way to test for this. Maybe C++26 static reflection will provide a solution.
+namespace std
+{
+    class source_location
+    {
+        struct __impl
+        {
+            const char* _M_file_name = nullptr;
+            const char* _M_function_name = nullptr;
+            unsigned _M_line = 0;
+            unsigned _M_column = 0;
+        };
+
+      public:
+        const __impl* _impl;
+
+        constexpr source_location() noexcept = default;
+
+        constexpr const char* file_name() const noexcept
+        {
+            return _impl->_M_file_name;
+        }
+
+        constexpr const char* function_name() const noexcept
+        {
+            return _impl->_M_function_name;
+        }
+
+        constexpr size_t line() const noexcept
+        {
+            return _impl->_M_line;
+        }
+
+        constexpr size_t column() const noexcept
+        {
+            return _impl->_M_column;
+        }
+
+        static consteval source_location current(
+            decltype(__builtin_source_location()) ptr = __builtin_source_location()) noexcept
+        {
+            source_location loc;
+            loc._impl = static_cast<const __impl*>(ptr);
+            return loc;
+        }
+    };
+} // namespace std
+
+#endif
 
 namespace tempest
 {
@@ -16,10 +70,8 @@ namespace tempest
                                                  const char* file = __builtin_FILE(),
                                                  const char* func = __builtin_FUNCSIG()) noexcept;
 #elif defined(__GNUC__)
-        static consteval source_location current(const uint32_t line = __builtin_LINE(),
-                                                 const uint32_t column = __builtin_COLUMN(),
-                                                 const char* file = __builtin_FILE(),
-                                                 const char* func = __builtin_source_location()->_M_function_name) noexcept;
+        static consteval source_location current(
+            decltype(__builtin_source_location()) ptr = __builtin_source_location()) noexcept;
 #else
 #error "Unsupported compiler."
 #endif
@@ -44,6 +96,7 @@ namespace tempest
         impl _impl;
     };
 
+#if defined(_MSC_VER)
     inline consteval source_location source_location::current(const uint32_t line, const uint32_t column,
                                                               const char* file, const char* func) noexcept
     {
@@ -54,6 +107,18 @@ namespace tempest
         loc._impl._column = column;
         return loc;
     }
+#else
+    inline consteval source_location source_location::current(decltype(__builtin_source_location()) ptr) noexcept
+    {
+        auto loc = std::source_location::current(ptr);
+        source_location result;
+        result._impl._file = loc.file_name();
+        result._impl._function = loc.function_name();
+        result._impl._line = loc.line();
+        result._impl._column = loc.column();
+        return result;
+    }
+#endif
 
     inline constexpr const char* source_location::file_name() const noexcept
     {