Echo Writes Code

errors.cpp

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#include "crucible/windows/errors.hpp"

#include "crucible/core/resource_warden.inl"
#include "crucible/windows/transcoding.hpp"

#include <Windows.h>

#include <sstream>
#include <type_traits>

static_assert(sizeof(::DWORD) <= sizeof(std::uint32_t));
static_assert(std::is_unsigned_v<::DWORD> == std::is_unsigned_v<std::uint32_t>);

namespace crucible::windows::errors {
  namespace {
    struct FormatWindowsError final {
      auto operator()(CreateDirectoryWFailed const &) const -> std::string {
        return "Call to host function CreateDirectoryW() failed";
      }

      auto operator()(CreateFileWFailed const &) const -> std::string {
        return "Call to host function CreateFileW() failed";
      }

      auto operator()(GetFileAttributesWFailed const &) const -> std::string {
        return "Call to host function GetFileAttributesW() failed";
      }

      auto operator()(GetFileSizeExFailed const &) const -> std::string {
        return "Call to host function GetFileSizeEX() failed";
      }

      auto operator()(FindFirstFileWFailed const &) const -> std::string {
        return "Call to host function FindFirstFileW() failed";
      }

      auto operator()(FindNextFileWFailed const &) const -> std::string {
        return "Call to host function FindNextFileW() failed";
      }

      auto operator()(MultiByteToWideCharFailed const &) const -> std::string {
        return "Call to host function MultiByteToWideChar() failed";
      }

      auto operator()(ReadFileFailed const &) const -> std::string {
        return "Call to host function ReadFile() failed";
      }

      auto operator()(RemoveDirectoryWFailed const &) const -> std::string {
        return "Call to host function RemoveDirectoryW() failed";
      }

      auto operator()(DeleteFileWFailed const &) const -> std::string {
        return "Call to host function DeleteFileW() failed";
      }

      auto operator()(WideCharToMultiByteFailed const &) const -> std::string {
        return "Call to host function WideCharToMultiByte() failed";
      }

      auto operator()(WriteFileFailed const &) const -> std::string {
        return "Call to host function WriteFile() failed";
      }

      auto operator()(InputTooLarge const &) const -> std::string {
        return "Input too large";
      }

      auto operator()(NegativeFileSize const &) const -> std::string {
        return "Negative file size";
      }

      auto operator()(OutputTruncated const &) const -> std::string {
        return "Output was truncated";
      }
    };

    struct SourceWindowsError final {
      auto operator()(CreateDirectoryWFailed const &e) const -> std::optional<std::reference_wrapper<core::errors::AbstractError const>> {
        return std::cref<core::errors::AbstractError>(e.host_error);
      }

      auto operator()(CreateFileWFailed const &e) const -> std::optional<std::reference_wrapper<core::errors::AbstractError const>> {
        return std::cref<core::errors::AbstractError>(e.host_error);
      }

      auto operator()(GetFileAttributesWFailed const &e) const -> std::optional<std::reference_wrapper<core::errors::AbstractError const>> {
        return std::cref<core::errors::AbstractError>(e.host_error);
      }

      auto operator()(GetFileSizeExFailed const &e) const -> std::optional<std::reference_wrapper<core::errors::AbstractError const>> {
        return std::cref<core::errors::AbstractError>(e.host_error);
      }

      auto operator()(FindFirstFileWFailed const &e) const -> std::optional<std::reference_wrapper<core::errors::AbstractError const>> {
        return std::cref<core::errors::AbstractError>(e.host_error);
      }

      auto operator()(FindNextFileWFailed const &e) const -> std::optional<std::reference_wrapper<core::errors::AbstractError const>> {
        return std::cref<core::errors::AbstractError>(e.host_error);
      }

      auto operator()(MultiByteToWideCharFailed const &e) const -> std::optional<std::reference_wrapper<core::errors::AbstractError const>> {
        return std::cref<core::errors::AbstractError>(e.host_error);
      }

      auto operator()(ReadFileFailed const &e) const -> std::optional<std::reference_wrapper<core::errors::AbstractError const>> {
        return std::cref<core::errors::AbstractError>(e.host_error);
      }

      auto operator()(RemoveDirectoryWFailed const &e) const -> std::optional<std::reference_wrapper<core::errors::AbstractError const>> {
        return std::cref<core::errors::AbstractError>(e.host_error);
      }

      auto operator()(DeleteFileWFailed const &e) const -> std::optional<std::reference_wrapper<core::errors::AbstractError const>> {
        return std::cref<core::errors::AbstractError>(e.host_error);
      }

      auto operator()(WideCharToMultiByteFailed const &e) const -> std::optional<std::reference_wrapper<core::errors::AbstractError const>> {
        return std::cref<core::errors::AbstractError>(e.host_error);
      }

      auto operator()(WriteFileFailed const &e) const -> std::optional<std::reference_wrapper<core::errors::AbstractError const>> {
        return std::cref<core::errors::AbstractError>(e.host_error);
      }

      auto operator()(InputTooLarge const &) const -> std::optional<std::reference_wrapper<core::errors::AbstractError const>> {
        return std::nullopt;
      }

      auto operator()(NegativeFileSize const &) const -> std::optional<std::reference_wrapper<core::errors::AbstractError const>> {
        return std::nullopt;
      }

      auto operator()(OutputTruncated const &) const -> std::optional<std::reference_wrapper<core::errors::AbstractError const>> {
        return std::nullopt;
      }
    };

    template<typename T>
    struct LocalFreeAdapter final {
      static_assert(std::is_pointer_v<T>);

      auto operator()(T pointer) const -> void {
        ::LocalFree(pointer);
      }
    };

    template<typename T>
    using LocalAllocWarden = core::resource_warden::ResourceWarden<T, LocalFreeAdapter<T>>;

    auto get_host_error_code() -> std::uint32_t {
      ::DWORD const error_dword { ::GetLastError() };
      return static_cast<std::uint32_t>(error_dword);
    }
  }

  HostError::HostError() :
    my_error_code { get_host_error_code() } {
  }

  HostError::~HostError() = default;

  auto HostError::format() const -> std::string {
    constexpr ::DWORD FLAGS { FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS | FORMAT_MESSAGE_MAX_WIDTH_MASK };
    constexpr ::DWORD LANGUAGE_ID { 0 };
    constexpr ::DWORD MINIMUM_SIZE { 0 };

    ::LPVOID message_source { nullptr };
    auto const error_dword { static_cast<::DWORD>(my_error_code) };
    ::LPWSTR raw_utf16_message { nullptr };
    auto dont_blame_me_blame_microsoft { reinterpret_cast<::LPWSTR>(&raw_utf16_message) };
    ::va_list *arguments { nullptr };

    ::DWORD const characters_written { ::FormatMessageW(FLAGS, message_source, error_dword, LANGUAGE_ID, dont_blame_me_blame_microsoft, MINIMUM_SIZE, arguments) };
    if (characters_written == 0) {
      ::DWORD const cause { ::GetLastError() };
      std::ostringstream buffer {};

      buffer
        << "Failed to format message for Windows API error code `" << my_error_code << "`"
        << " "
        << "(Error code returned from FormatMessageW() was: `" << cause << "`)";

      return buffer.str();
    }

    LocalAllocWarden<::LPWSTR> warden(raw_utf16_message);

    ::DWORD const characters_written_excluding_terminator { characters_written - 1 };
    std::wstring const utf16_message(raw_utf16_message, characters_written_excluding_terminator);

    auto const transcoding_result { transcoding::transcode_utf16_to_utf8(utf16_message) };
    if (transcoding_result.has_failure()) {
      std::ostringstream buffer {};
      buffer << "Failed to transcode Windows API error message from UTF16 to UTF8 for error code `" << my_error_code << "`";
      return buffer.str();
    }

    return std::move(transcoding_result).get_success();
  }

  auto HostError::source() const & -> std::optional<std::reference_wrapper<core::errors::AbstractError const>> {
    return std::nullopt;
  }

  WindowsError::WindowsError(CreateDirectoryWFailed const &variant) :
    my_variant { variant } {
  }

  WindowsError::WindowsError(CreateFileWFailed const &variant) :
    my_variant { variant } {
  }

  WindowsError::WindowsError(GetFileAttributesWFailed const &variant) :
    my_variant { variant } {
  }

  WindowsError::WindowsError(GetFileSizeExFailed const &variant) :
    my_variant { variant } {
  }

  WindowsError::WindowsError(FindFirstFileWFailed const &variant) :
    my_variant { variant } {
  }

  WindowsError::WindowsError(FindNextFileWFailed const &variant) :
    my_variant { variant } {
  }

  WindowsError::WindowsError(MultiByteToWideCharFailed const &variant) :
    my_variant { variant } {
  }

  WindowsError::WindowsError(ReadFileFailed const &variant) :
    my_variant { variant } {
  }

  WindowsError::WindowsError(RemoveDirectoryWFailed const &variant) :
    my_variant { variant } {
  }

  WindowsError::WindowsError(DeleteFileWFailed const &variant) :
    my_variant { variant } {
  }

  WindowsError::WindowsError(WideCharToMultiByteFailed const &variant) :
    my_variant { variant } {
  }

  WindowsError::WindowsError(WriteFileFailed const &variant) :
    my_variant { variant } {
  }

  WindowsError::WindowsError(InputTooLarge const &variant) :
    my_variant { variant } {
  }

  WindowsError::WindowsError(NegativeFileSize const &variant) :
    my_variant { variant } {
  }

  WindowsError::WindowsError(OutputTruncated const &variant) :
    my_variant { variant } {
  }

  WindowsError::~WindowsError() = default;

  auto WindowsError::format() const -> std::string {
    return std::visit(FormatWindowsError {}, my_variant);
  }

  auto WindowsError::source() const & -> std::optional<std::reference_wrapper<core::errors::AbstractError const>> {
    return std::visit(SourceWindowsError {}, my_variant);
  }
}