Linux: check that device has not been disconnected

Author: manuelbl

java-does-usb/src/main/java/net/codecrete/usb/common/UsbDeviceImpl.java

@@ -95,6 +95,18 @@ protected void checkIsOpen() {
             throw new UsbException("device needs to be opened first for this operation");
     }
 
+    protected void checkIsClosed(String message) {
+        if (!connected)
+            throw new UsbException("device has been disconnected");
+        if (isOpened())
+            throw new UsbException(message);
+    }
+
+    protected synchronized void disconnect() {
+        connected = false;
+        close();
+    }
+
     @Override
     public int getProductId() {
         return pid;

java-does-usb/src/main/java/net/codecrete/usb/common/UsbDeviceRegistry.java

@@ -204,9 +204,9 @@ protected void closeAndRemoveDevice(Object deviceId) {
             return;
 
         try {
-            device.close();
+            ((UsbDeviceImpl)device).disconnect();
         } catch (Exception e) {
-            LOG.log(INFO, "failed to close USB device - ignoring exception", e);
+            LOG.log(INFO, "failed to close disconnected USB device - ignoring exception", e);
         }
 
         removeDevice(deviceId);

java-does-usb/src/main/java/net/codecrete/usb/linux/LinuxUsbDevice.java

@@ -71,16 +71,14 @@ private void loadDescription(String path) {
     }
 
     @Override
-    public void detachStandardDrivers() {
-        if (isOpened())
-            throwException("detachStandardDrivers() must not be called while the device is open");
+    public synchronized void detachStandardDrivers() {
+        checkIsClosed("detachStandardDrivers() must not be called while the device is open");
         detachDrivers = true;
     }
 
     @Override
-    public void attachStandardDrivers() {
-        if (isOpened())
-            throwException("attachStandardDrivers() must not be called while the device is open");
+    public synchronized void attachStandardDrivers() {
+        checkIsClosed("attachStandardDrivers() must not be called while the device is open");
         detachDrivers = false;
     }
 
@@ -91,8 +89,7 @@ public boolean isOpened() {
 
     @Override
     public synchronized void open() {
-        if (isOpened())
-            throwException("device is already open");
+        checkIsClosed("device is already open");
 
         try (var arena = Arena.ofConfined()) {
             var pathUtf8 = arena.allocateFrom(uniqueDeviceId.toString());

java-does-usb/src/main/java/net/codecrete/usb/macos/MacosUsbDevice.java

@@ -98,13 +98,6 @@ public boolean isOpened() {
         return claimedInterfaces != null;
     }
 
-    private void checkIsClosed(String message) {
-        if (!connected)
-            throwException("device has been disconnected");
-        if (isOpened())
-            throwException(message);
-    }
-
     @SuppressWarnings("java:S2276")
     @Override
     public synchronized void open() {
@@ -164,9 +157,9 @@ public synchronized void close() {
             asyncTask.removeEventSource(source);
     }
 
-    synchronized void closeFully() {
-        connected = false;
-        close();
+    @Override
+    protected synchronized void disconnect() {
+        super.disconnect();
         IoKitUsb.Release(device);
         device = null;
     }

java-does-usb/src/main/java/net/codecrete/usb/macos/MacosUsbDeviceRegistry.java

@@ -267,19 +267,7 @@ private void onDevicesConnected(MemorySegment ignoredRefCon, int iterator) {
     private void onDevicesDisconnected(MemorySegment ignoredRefCon, int iterator) {
 
         // process device iterator for disconnected devices
-        iterateDevices(iterator, (entryId, _, _) -> {
-            var device = findDevice(entryId);
-            if (device == null)
-                return;
-
-            try {
-                ((MacosUsbDevice) device).closeFully();
-            } catch (Exception e) {
-                LOG.log(INFO, "failed to close USB device - ignoring exception", e);
-            }
-
-            removeDevice(entryId);
-        });
+        iterateDevices(iterator, (entryId, _, _) -> closeAndRemoveDevice(entryId));
     }
 
     @FunctionalInterface

java-does-usb/src/test/java/net/codecrete/usb/special/Unplug.java

@@ -65,7 +65,8 @@ private static void onUnpluggedDevice(UsbDevice device) {
                 device.open();
                 System.err.println("Device should not be openable after disconnect");
             } catch (UsbException e) {
-                // expected
+                if (!e.getMessage().contains("disconnected"))
+                    System.err.println(STR."Unexpected error: \{e.getMessage()}");
             }
         }).start();
     }