Add low memory warning (#417)

Tactility/Private/Tactility/service/memorychecker/MemoryCheckerService.h

@@ -0,0 +1,33 @@
+#pragma once
+
+#include "Tactility/service/Service.h"
+
+#include <Tactility/Mutex.h>
+#include <Tactility/Timer.h>
+
+namespace tt::service::memorychecker {
+
+/**
+ * Runs a background timer that validates if there's sufficient memory available.
+ * It shows a statusbar icon when memory is low. It also outputs warning to the log.
+ */
+class MemoryCheckerService final : public Service {
+
+    Mutex mutex = Mutex(Mutex::Type::Recursive);
+    Timer timer = Timer(Timer::Type::Periodic, [this] { onTimerUpdate(); });
+
+    // LVGL Statusbar icon
+    int8_t statusbarIconId = -1;
+    // Keep track of state to minimize UI updates
+    bool memoryLow = false;
+
+    void onTimerUpdate();
+
+public:
+
+    bool onStart(ServiceContext& service) override;
+
+    void onStop(ServiceContext& service) override;
+};
+
+}