hid: define easy error data setter function

Sets all error data, including an optional error message.
Ensures any previous error data is freed before overwriting.

Optional error message is meant to be used in the cases
the libusb documentation goes into detail as to what happened.

Author: matheusmoreira

libusb/hid.c

@@ -409,6 +409,21 @@ static wchar_t *libusb_strerror_wchar(int error) {
 	return utf8_to_wchar(s);
 }
 
+static void set_error(hid_device *dev, int error, const wchar_t *custom_string)
+{
+	if (dev->error_name) {
+		free(dev->error_name);
+	}
+
+	if (dev->error_string) {
+		free(dev->error_string);
+	}
+
+	dev->error = error;
+	dev->error_name = libusb_error_name_wchar(error);
+	dev->error_string = custom_string?
+		wcsdup(custom_string) : libusb_strerror_wchar(error);
+}
 
 /* This function returns a newly allocated wide string containing the USB
    device string numbered by the index. The returned string must be freed