make GetCurrentModulePath and GetShortcutPath throw win32 errors

plugins/windows-notification/api/include/win32.hpp

@@ -3,14 +3,35 @@
 #include <glib.h>
 
 #ifdef __cplusplus
-
 #include <string>
-#include <array>
-#include <optional>
-#include <memory>
+#include <cstdint>
+#include <exception>
+#include <iterator>
 
-std::optional<std::wstring> GetCurrentModulePath();
-std::optional<std::wstring> GetShortcutPath();
+#include "make_array.hpp"
+#include "hexify.hpp"
+
+struct win32_error : std::exception
+{
+    std::uint32_t code;
+    explicit win32_error() noexcept;  // initializes with GetLastError()
+    explicit win32_error(const std::uint32_t code) noexcept
+        : code{code}
+    {}
+    const char *what() const noexcept override
+    {
+        // NOTE: thread-unsafe
+        // TODO: decimal representation seems to be more usual for win32 errors
+        msg = make_array("win32 error 0x01234567\0");
+        hexify32(code, std::end(msg)-1);
+        return std::data(msg);
+    }
+private:
+    mutable std::array<char,22+1> msg;
+};
+
+std::wstring GetCurrentModulePath();
+std::wstring GetShortcutPath();
 
 #define EXTERN    extern "C"
 #define NOEXCEPT  noexcept

plugins/windows-notification/api/src/shortcutcreator.cpp

@@ -136,19 +136,15 @@ bool ImplEnsureAumiddedShortcutExists(const char *const aumid)
     auto exePath = GetCurrentModulePath();
     auto shortcutPath = GetShortcutPath();
 
-    if (shortcutPath && exePath)
-    {
-        auto path = shortcutPath.value() + LR"(\Microsoft\Windows\Start Menu\Programs\Dino.lnk)";
+    auto path = shortcutPath + LR"(\Microsoft\Windows\Start Menu\Programs\Dino.lnk)";
     if (!std::filesystem::exists(path))
     {
-            return SUCCEEDED(InstallShortcut(exePath.value(), waumid, path));
+        return SUCCEEDED(InstallShortcut(exePath, waumid, path));
     }
     else
     {
         return SUCCEEDED(ValidateShortcut(path, waumid));
     }
-    }
-    return false;
 }
 
 extern "C"

plugins/windows-notification/api/src/win32.cpp

@@ -5,7 +5,11 @@
 #include "converter.hpp"
 #include "ginvoke.hpp"
 
-std::optional<std::wstring> GetCurrentModulePath()
+win32_error::win32_error() noexcept
+    : win32_error{::GetLastError()}
+{}
+
+std::wstring GetCurrentModulePath()
 {
     std::wstring exePath(MAX_PATH, 0);
     auto charWritten = GetModuleFileName(nullptr, exePath.data(), exePath.size());
@@ -14,10 +18,10 @@ std::optional<std::wstring> GetCurrentModulePath()
         exePath.resize(charWritten);
         return exePath;
     }
-    return std::nullopt;
+    throw win32_error{};
 }
 
-std::optional<std::wstring> GetShortcutPath()
+std::wstring GetShortcutPath()
 {
     std::wstring shortcutPath(MAX_PATH, 0);
     auto charWritten = GetEnvironmentVariable(L"APPDATA", shortcutPath.data(), shortcutPath.size());
@@ -26,7 +30,7 @@ std::optional<std::wstring> GetShortcutPath()
         shortcutPath.resize(charWritten);
         return shortcutPath;
     }
-    return std::nullopt;
+    throw win32_error{};
 }
 
 bool ImplSetProcessAumid(const char *const aumid)