MSIX: implement initial version of notifications library (#1178)

src/common/notifications_winrt/BackgroundHandler.cpp

@@ -0,0 +1,27 @@
+#include "pch.h"
+#include "BackgroundHandler.h"
+#include "BackgroundHandler.g.cpp"
+
+#include "handler_functions.h"
+
+namespace winrt::PowerToysNotifications::implementation
+{
+    using Windows::ApplicationModel::Background::IBackgroundTaskInstance;
+    using Windows::UI::Notifications::ToastNotificationActionTriggerDetail;
+    using Windows::Foundation::WwwFormUrlDecoder;
+
+    void BackgroundHandler::Run(IBackgroundTaskInstance bti)
+    {
+        const auto details = bti.TriggerDetails().try_as<ToastNotificationActionTriggerDetail>();
+        if (!details)
+        {
+            return;
+        }
+
+        WwwFormUrlDecoder decoder{details.Argument()};
+
+        const size_t button_id = std::stoi(decoder.GetFirstValueByName(L"button_id").c_str());
+        auto handler = decoder.GetFirstValueByName(L"handler");
+        dispatch_to_backround_handler(std::move(handler), std::move(bti), button_id);
+    }
+}