- android: handle exits correctly, since as stated in SDl2 docs, std::exit() doesn't work, so trowing an exception, catching it in the main a,dn exiting via return there

- core/errors.hpp: add virtual override for std::exception what(), so that it gets a correct message, if it's used wrongly

Author: Totto16

src/executables/game/application.cpp

@@ -361,7 +361,8 @@ void Application::initialize() {
         spdlog::debug("Aborted loading after {}", duration);
 
         // just exit immediately, without cleaning up, since than we would have to cancel the loading thread somehow, which is way rto complicated, let the OS clean up our mess we create her xD
-        std::exit(0);
+
+        utils::exit(0);
     }
 
 

src/executables/game/main.cpp

@@ -129,6 +129,9 @@ namespace {
 
 
             return EXIT_FAILURE;
+        } catch (const utils::ExitException& exit_exception) {
+            spdlog::debug("Requested exit with status code {}", exit_exception.status_code());
+            return exit_exception.status_code();
         } catch (const std::exception& error) {
             // this is the last resort, so using std::cerr and no sdl show_simple messagebox!
             std::cerr << error.what();

src/helper/graphic_utils.cpp

@@ -1,5 +1,6 @@
 
 #include "graphic_utils.hpp"
+#include <exception>
 
 SDL_Color utils::sdl_color_from_color(const Color& color) {
     return SDL_Color{ color.r, color.g, color.b, color.a };
@@ -94,3 +95,25 @@ std::optional<bool> utils::log_error(const std::string& error) {
     spdlog::error(error);
     return std::nullopt;
 }
+
+utils::ExitException::ExitException(int status_code) noexcept : m_status_code{ status_code } { }
+
+[[nodiscard]] int utils::ExitException::status_code() const {
+    return m_status_code;
+}
+
+[[nodiscard]] const char* utils::ExitException::what() const noexcept {
+    return "An exit exception occurred";
+}
+
+void utils::exit(int status_code) {
+#if defined(__ANDROID__)
+    // calling exit() in android doesn't do the correct job, it completely avoids resource cleanup by the underlying SDLActivity.java
+    // (java wrapper), that calls the main and expects it to return ALWAYS and throwing an exception in a catch statement is bad,
+    // but is required here
+    // see: https://github.com/libsdl-org/SDL/blob/main/docs/README-android.md
+    throw utils::ExitException{ status_code };
+#else
+    std::exit(status_code);
+#endif
+}

src/helper/graphic_utils.hpp

@@ -20,4 +20,20 @@ namespace utils {
     [[nodiscard]] std::filesystem::path get_root_folder();
 
     std::optional<bool> log_error(const std::string& error);
+
+    struct ExitException : std::exception {
+    private:
+        int m_status_code;
+
+    public:
+        explicit ExitException(int status_code) noexcept;
+
+        [[nodiscard]] int status_code() const;
+
+        [[nodiscard]] const char* what() const noexcept override;
+    };
+
+
+    [[noreturn]] void exit(int status_code);
+
 } // namespace utils

src/libs/core/helper/errors.cpp

@@ -21,6 +21,11 @@ helper::GeneralError::GeneralError(GeneralError&& error) noexcept = default;
     return m_message;
 }
 
+[[nodiscard]] const char* helper::GeneralError::what() const noexcept {
+    return m_message.c_str();
+}
+
+
 [[nodiscard]] helper::error::Severity helper::GeneralError::severity() const {
     return m_severity;
 }

src/libs/core/helper/errors.hpp

@@ -31,6 +31,8 @@ namespace helper {
 
         [[nodiscard]] const std::string& message() const;
         [[nodiscard]] error::Severity severity() const;
+
+        [[nodiscard]] const char* what() const noexcept override;
     };
 
     struct FatalError : public GeneralError {