macOS: Deal with larger device descriptors

Author: manuelbl

.github/workflows/continuous-integration.yaml

@@ -26,11 +26,11 @@ jobs:
     steps:
       - uses: actions/checkout@v3
       - name: Setup Java
-        uses: oracle-actions/setup-java@v1
+        uses: actions/setup-java@v3
         with:
-          website: jdk.java.net
-          release: '21'
-          version: latest
+          distribution: 'zulu'
+          java-version: '21'
+          cache: 'maven'
       - name: Configure GPG key
         run: |
           echo -n "$GPG_SIGNING_KEY" | base64 --decode | gpg --import

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

@@ -16,7 +16,6 @@
 import net.codecrete.usb.macos.gen.iokit.IOUSBFindInterfaceRequest;
 import net.codecrete.usb.usbstandard.ConfigurationDescriptor;
 import net.codecrete.usb.usbstandard.Constants;
-import net.codecrete.usb.usbstandard.DeviceDescriptor;
 
 import java.io.InputStream;
 import java.io.OutputStream;
@@ -159,17 +158,21 @@ synchronized void closeFully() {
     private void loadDescription(MemorySegment device) {
         try (var arena = Arena.ofConfined()) {
 
-            var data = arena.allocate(DeviceDescriptor.LAYOUT.byteSize());
-            var ret = IoKitUSB.DeviceRequest(device, createDeviceRequest(arena, USBDirection.IN, new USBControlTransfer(
+            // retrieve device descriptor using synchronous control transfer
+            var data = arena.allocate(255);
+            var deviceRequest = createDeviceRequest(arena, USBDirection.IN, new USBControlTransfer(
                     USBRequestType.STANDARD,
                     USBRecipient.DEVICE,
                     6, // get descriptor
                     Constants.DEVICE_DESCRIPTOR_TYPE << 8,
                     0
-            ), data));
+            ), data);
+            var ret = IoKitUSB.DeviceRequest(device, deviceRequest);
             if (ret != 0)
                 throwException(ret, "querying device descriptor failed");
-            rawDeviceDescriptor = data.toArray(JAVA_BYTE);
+
+            var len = IOUSBDevRequest.wLenDone$get(deviceRequest);
+            rawDeviceDescriptor = data.asSlice(0, len).toArray(JAVA_BYTE);
 
             configurationValue = 0;