windows: Cover all enumeration passes explicitly in switch statements

This is only for readability and doesn't change the behaviour.

Several passes were implicitly grouped together in the "default" case,
which made the code unnecessarily hard to read. The reason was that the
number of EXT passes is not known, so those were conveniently treated in
the "default" case together with some non-EXT passes.

Instead introduce a "pass_type" helper variable which has a defined
range, and add all pass types explicitly in the switch statements.

At the same time update the comment which shortly explains the different
passes, it hasn't reflected reality for a long while.

Signed-off-by: Tormod Volden <[email protected]>

libusb/os/windows_winusb.c

@@ -1462,7 +1462,7 @@ static int winusb_get_device_list(struct libusb_context *ctx, struct discovered_
 	GUID hid_guid;
 	int r = LIBUSB_SUCCESS;
 	int api, sub_api;
-	unsigned int pass, i, j;
+	unsigned int pass, pass_type, i, j;
 	char enumerator[16];
 	char dev_id[MAX_PATH_LENGTH];
 	struct libusb_device *dev, *parent_dev;
@@ -1497,13 +1497,14 @@ static int winusb_get_device_list(struct libusb_context *ctx, struct discovered_
 	unsigned int unref_cur = 0;
 	DWORD hub_port_nr;
 
-	// PASS 1 : (re)enumerate HCDs (allows for HCD hotplug)
-	// PASS 2 : (re)enumerate HUBS
-	// PASS 3 : (re)enumerate generic USB devices (including driverless)
-	//           and list additional USB device interface GUIDs to explore
-	// PASS 4 : (re)enumerate master USB devices that have a device interface
-	// PASS 5+: (re)enumerate device interfaced GUIDs (including HID) and
-	//           set the device interfaces.
+	// PASS 0 : enumerate HUBs
+	// PASS 1 : (re)enumerate master devices that have a DEVice interface
+	// PASS 2 : (re)enumerate HCDs (allow for HCD hotplug)
+	// PASS 3 : (re)enumerate GENeric devices (including driverless)
+	//           and list additional device interface GUIDs to explore
+	// PASS 4 : (re)enumerate device interface GUIDs (including HID)
+	//           and set the device interfaces
+	// PASS 5+: (re)enumerate additional EXTra GUID devices
 
 	// Init the GUID table
 	guid_list = malloc(guid_size * sizeof(void *));
@@ -1540,10 +1541,11 @@ static int winusb_get_device_list(struct libusb_context *ctx, struct discovered_
 	}
 
 	for (pass = 0; ((pass < nb_guids) && (r == LIBUSB_SUCCESS)); pass++) {
+		pass_type = MIN(pass, EXT_PASS);
 //#define ENUM_DEBUG
 #if defined(ENABLE_LOGGING) && defined(ENUM_DEBUG)
 		const char * const passname[] = {"HUB", "DEV", "HCD", "GEN", "HID", "EXT"};
-		usbi_dbg(ctx, "#### PROCESSING %ss %s", passname[MIN(pass, EXT_PASS)], guid_to_string(guid_list[pass], guid_string));
+		usbi_dbg(ctx, "#### PROCESSING %ss %s", passname[pass_type], guid_to_string(guid_list[pass], guid_string));
 #endif
 		if ((pass == HID_PASS) && (guid_list[HID_PASS] == NULL))
 			continue;
@@ -1596,7 +1598,7 @@ static int winusb_get_device_list(struct libusb_context *ctx, struct discovered_
 			// Set API to use or get additional data from generic pass
 			api = USB_API_UNSUPPORTED;
 			sub_api = SUB_API_NOTSET;
-			switch (pass) {
+			switch (pass_type) {
 			case HCD_PASS:
 				break;
 			case HUB_PASS:
@@ -1696,7 +1698,8 @@ static int winusb_get_device_list(struct libusb_context *ctx, struct discovered_
 			case HID_PASS:
 				api = USB_API_HID;
 				break;
-			default:
+			case DEV_PASS:
+			case EXT_PASS:
 				// Get the API type (after checking that the driver installation is OK)
 				if ((!pSetupDiGetDeviceRegistryPropertyA(*dev_info, &dev_info_data, SPDRP_INSTALL_STATE,
 					NULL, (PBYTE)&install_state, sizeof(install_state), &size)) || (size != sizeof(install_state))) {
@@ -1709,6 +1712,8 @@ static int winusb_get_device_list(struct libusb_context *ctx, struct discovered_
 				}
 				get_api_type(dev_info, &dev_info_data, &api, &sub_api);
 				break;
+			default:
+				assert(false); // unreachable since all pass types covered explicitly
 			}
 
 			// Find parent device (for the passes that need it)
@@ -1788,7 +1793,7 @@ static int winusb_get_device_list(struct libusb_context *ctx, struct discovered_
 			}
 
 			// Setup device
-			switch (pass) {
+			switch (pass_type) {
 			case HUB_PASS:
 			case DEV_PASS:
 				// If the device has already been setup, don't do it again
@@ -1857,7 +1862,8 @@ static int winusb_get_device_list(struct libusb_context *ctx, struct discovered_
 					r = LIBUSB_SUCCESS;
 				}
 				break;
-			default: // HID_PASS and later
+			case HID_PASS:
+			case EXT_PASS:
 				if (parent_priv->apib->id == USB_API_HID || parent_priv->apib->id == USB_API_COMPOSITE) {
 					if (parent_priv->apib->id == USB_API_HID) {
 						usbi_dbg(ctx, "setting HID interface for [%lX]:", parent_dev->session_data);
@@ -1881,6 +1887,8 @@ static int winusb_get_device_list(struct libusb_context *ctx, struct discovered_
 				}
 				libusb_unref_device(parent_dev);
 				break;
+			default:
+				assert(false); // unreachable since all pass types covered explicitly
 			}
 		}
 	}