vbox: cleanup vboxAttachUSB

This cleanup flattens deeply nested code.
Signed-off-by: NRyota Ozaki <ozaki.ryota@gmail.com>

src/vbox/vbox_tmpl.c

@@ -4852,28 +4852,35 @@ vboxAttachUSB(virDomainDefPtr def, vboxGlobalData *data, IMachine *machine)
      * usual
      */
     for (i = 0; i < def->nhostdevs; i++) {
-        if (def->hostdevs[i]->mode ==
-            VIR_DOMAIN_HOSTDEV_MODE_SUBSYS) {
-            if (def->hostdevs[i]->source.subsys.type ==
-                VIR_DOMAIN_HOSTDEV_SUBSYS_TYPE_USB) {
-                if (def->hostdevs[i]->source.subsys.u.usb.vendor ||
-                    def->hostdevs[i]->source.subsys.u.usb.product) {
+        if (def->hostdevs[i]->mode != VIR_DOMAIN_HOSTDEV_MODE_SUBSYS)
+            continue;
+
+        if (def->hostdevs[i]->source.subsys.type !=
+            VIR_DOMAIN_HOSTDEV_SUBSYS_TYPE_USB)
+            continue;
+
+        if (!def->hostdevs[i]->source.subsys.u.usb.vendor &&
+            !def->hostdevs[i]->source.subsys.u.usb.product)
+            continue;
+
         VIR_DEBUG("USB Device detected, VendorId:0x%x, ProductId:0x%x",
                   def->hostdevs[i]->source.subsys.u.usb.vendor,
                   def->hostdevs[i]->source.subsys.u.usb.product);
         isUSB = true;
         break;
     }
-            }
-        }
-    }
 
-    if (isUSB) {
+    if (!isUSB)
+        return;
+
     /* First Start the USB Controller and then loop
      * to attach USB Devices to it
      */
     machine->vtbl->GetUSBController(machine, &USBController);
-        if (USBController) {
+
+    if (!USBController)
+        return;
+
     USBController->vtbl->SetEnabled(USBController, 1);
 #if VBOX_API_VERSION < 4002
     USBController->vtbl->SetEnabledEhci(USBController, 1);
@@ -4882,14 +4889,20 @@ vboxAttachUSB(virDomainDefPtr def, vboxGlobalData *data, IMachine *machine)
 #endif
 
     for (i = 0; i < def->nhostdevs; i++) {
-                if (def->hostdevs[i]->mode ==
-                    VIR_DOMAIN_HOSTDEV_MODE_SUBSYS) {
-                    if (def->hostdevs[i]->source.subsys.type ==
-                        VIR_DOMAIN_HOSTDEV_SUBSYS_TYPE_USB) {
-
         char *filtername           = NULL;
         PRUnichar *filternameUtf16 = NULL;
         IUSBDeviceFilter *filter   = NULL;
+        PRUnichar *vendorIdUtf16  = NULL;
+        char vendorId[40]         = {0};
+        PRUnichar *productIdUtf16 = NULL;
+        char productId[40]        = {0};
+
+        if (def->hostdevs[i]->mode != VIR_DOMAIN_HOSTDEV_MODE_SUBSYS)
+            continue;
+
+        if (def->hostdevs[i]->source.subsys.type !=
+            VIR_DOMAIN_HOSTDEV_SUBSYS_TYPE_USB)
+            continue;
 
         /* Zero pad for nice alignment when fewer than 9999
          * devices.
@@ -4903,14 +4916,12 @@ vboxAttachUSB(virDomainDefPtr def, vboxGlobalData *data, IMachine *machine)
         }
         VBOX_UTF16_FREE(filternameUtf16);
 
-                        if (filter &&
-                            (def->hostdevs[i]->source.subsys.u.usb.vendor ||
-                             def->hostdevs[i]->source.subsys.u.usb.product)) {
+        if (!filter)
+            continue;
 
-                            PRUnichar *vendorIdUtf16  = NULL;
-                            char vendorId[40]         = {0};
-                            PRUnichar *productIdUtf16 = NULL;
-                            char productId[40]        = {0};
+        if (!def->hostdevs[i]->source.subsys.u.usb.vendor &&
+            !def->hostdevs[i]->source.subsys.u.usb.product)
+            continue;
 
         if (def->hostdevs[i]->source.subsys.u.usb.vendor) {
             snprintf(vendorId, sizeof(vendorId), "%x",
@@ -4933,13 +4944,7 @@ vboxAttachUSB(virDomainDefPtr def, vboxGlobalData *data, IMachine *machine)
                                                 filter);
         VBOX_RELEASE(filter);
     }
-
-                    }
-                }
-            }
     VBOX_RELEASE(USBController);
-        }
-    }
 }
 
 static void