add geode::terminate and geode::unreachable

loader/include/Geode/utils/terminate.hpp

@@ -0,0 +1,54 @@
+#pragma once
+
+#include "../DefaultInclude.hpp"
+#include "../loader/Log.hpp"
+#include <source_location>
+
+namespace geode {
+    class Mod;
+}
+
+namespace geode::utils {
+    namespace detail {
+        // This needs to do stuff with `Mod*` which is not included in the file
+        GEODE_DLL std::string fmtTerminateError(const char* reason, Mod* mod, std::source_location loc);
+    }
+
+    template <class = void>
+    [[noreturn]]
+    void terminate(
+        std::string const& reason,
+        Mod* mod = getMod(),
+        std::source_location loc = std::source_location::current()
+    ) {
+        auto fullError = detail::fmtTerminateError(reason.c_str(), mod, loc);
+
+        // Add the error to the logfile
+        log::error("{}", fullError);
+
+    #ifdef GEODE_IS_WINDOWS
+        // If a debugger is attached, start debugging
+        if (IsDebuggerPresent()) {
+            OutputDebugStringA(reason.c_str());
+            DebugBreak();
+        }
+        // Otherwise just terminate
+        else {
+            MessageBoxA(nullptr, "A Mod Crashed", fullError.c_str(), MB_ICONERROR);
+            std::terminate();
+        }
+    #else
+        std::terminate();
+    #endif
+    }
+    
+    template <class = void>
+    [[noreturn]]
+    void unreachable(
+        std::string const& reason = "Unspecified",
+        Mod* mod = getMod(),
+        std::source_location loc = std::source_location::current()
+    ) {
+        return terminate(reason + " (Unreachable code path)", mod, loc);
+    }
+}

loader/src/utils/terminate.cpp

@@ -0,0 +1,14 @@
+#include <Geode/utils/terminate.hpp>
+#include <Geode/loader/Mod.hpp>
+
+using namespace geode::prelude;
+
+std::string geode::utils::detail::fmtTerminateError(const char* reason, Mod* mod, std::source_location loc) {
+    return fmt::format(
+        "The mod '{}' by {} has deliberately asked the game to crash.\n"
+        "Reason: {}\n"
+        "Source: {}::{}():{}:{}",
+        mod->getID(), mod->getDeveloper(), reason,
+        loc.file_name(), loc.function_name(), loc.line(), loc.column()
+    );
+}