Added Usb Detection using libUsb

src/Usb.cpp

@@ -2,36 +2,45 @@
 
 #include <iostream>
 #include <iomanip>
+#include <optional>
+#include <spdlog/spdlog.h>
 
 namespace ptprnt::driver {
 
 Usb::Usb() {
-    std::cout << "Usb starting" << std::endl;
+    spdlog::debug("Usb constructing");
     libusb_init(NULL);
 }
 Usb::~Usb() {
-    std::cout << "Usb stopping" << std::endl;
+    spdlog::debug("Usb destructing");
 }
 
-std::vector<UsbDevice> Usb::listDevices() {
+std::optional<std::vector<UsbDevice>> Usb::getDevices() {
     libusb_device ** devs;
     libusb_device *dev;
     struct libusb_device_descriptor desc;
     int r,i=0;
 
+    mDevices.clear();
+
     libusb_get_device_list(NULL, &devs);
 
     while ((dev=devs[i++]) != NULL) {
+        UsbDevice newDev;
+
 		if ((r=libusb_get_device_descriptor(dev, &desc)) < 0) {
-			std::cerr << "failed to open device" << std::endl;
+			spdlog::error("failed to open device");
 			libusb_free_device_list(devs, 1);
+            return std::nullopt;
 		}
 
-        std::cout << std::hex << std::setw(4) << desc.idVendor << ":" << desc.idProduct;
-        std::cout << std::endl;
+        newDev.vendorId = desc.idVendor;
+        newDev.productId = desc.idProduct;
+
+        mDevices.push_back(newDev);
     }
 
-    return std::vector<UsbDevice>();
+    return mDevices;
 }
 
 }  // namespace ptprnt::driver