implemented Go API for attachmentWasDisconnectedWithError

Author: Code-Hex

configuration.go

@@ -38,6 +38,7 @@ type VirtualMachineConfiguration struct {
 	memorySize uint64
 	*pointer
 
+	networkDeviceConfiguration []*VirtioNetworkDeviceConfiguration
 	storageDeviceConfiguration []StorageDeviceConfiguration
 }
 
@@ -116,20 +117,13 @@ func (v *VirtualMachineConfiguration) SetNetworkDevicesVirtualMachineConfigurati
 	}
 	array := objc.ConvertToNSMutableArray(ptrs)
 	C.setNetworkDevicesVZVirtualMachineConfiguration(objc.Ptr(v), objc.Ptr(array))
+	v.networkDeviceConfiguration = cs
 }
 
 // NetworkDevices return the list of network device configuration set in this virtual machine configuration.
 // Return an empty array if no network device configuration is set.
 func (v *VirtualMachineConfiguration) NetworkDevices() []*VirtioNetworkDeviceConfiguration {
-	nsArray := objc.NewNSArray(
-		C.networkDevicesVZVirtualMachineConfiguration(objc.Ptr(v)),
-	)
-	ptrs := nsArray.ToPointerSlice()
-	networkDevices := make([]*VirtioNetworkDeviceConfiguration, len(ptrs))
-	for i, ptr := range ptrs {
-		networkDevices[i] = newVirtioNetworkDeviceConfiguration(ptr)
-	}
-	return networkDevices
+	return v.networkDeviceConfiguration
 }
 
 // SetSerialPortsVirtualMachineConfiguration sets list of serial ports. Empty by default.

internal/sliceutil/sliceutil.go

@@ -0,0 +1,12 @@
+package sliceutil
+
+// FindValueByIndex returns the value of the index in s,
+// or -1 if not present.
+func FindValueByIndex[S ~[]E, E any](s S, idx int) (v E) {
+	for i := range s {
+		if i == idx {
+			return s[i]
+		}
+	}
+	return v
+}

internal/sliceutil/sliceutil_test.go

@@ -0,0 +1,50 @@
+package sliceutil_test
+
+import (
+	"testing"
+
+	"github.com/Code-Hex/vz/v3/internal/sliceutil"
+)
+
+func TestFindValueByIndex(t *testing.T) {
+	tests := []struct {
+		name     string
+		slice    []int
+		index    int
+		expected int
+	}{
+		{
+			name:     "Index within range",
+			slice:    []int{1, 2, 3, 4, 5},
+			index:    2,
+			expected: 3,
+		},
+		{
+			name:     "Index out of range",
+			slice:    []int{1, 2, 3, 4, 5},
+			index:    10,
+			expected: 0, // default value of int
+		},
+		{
+			name:     "Negative index",
+			slice:    []int{1, 2, 3, 4, 5},
+			index:    -1,
+			expected: 0, // default value of int
+		},
+		{
+			name:     "Empty slice",
+			slice:    []int{},
+			index:    0,
+			expected: 0, // default value of int
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			result := sliceutil.FindValueByIndex(tt.slice, tt.index)
+			if result != tt.expected {
+				t.Errorf("FindValueByIndex(%v, %d) = %v; want %v", tt.slice, tt.index, result, tt.expected)
+			}
+		})
+	}
+}

network.go

@@ -12,7 +12,6 @@ import (
 	"net"
 	"os"
 	"syscall"
-	"unsafe"
 
 	"github.com/Code-Hex/vz/v3/internal/objc"
 )
@@ -91,6 +90,10 @@ type NATNetworkDeviceAttachment struct {
 	*baseNetworkDeviceAttachment
 }
 
+func (*NATNetworkDeviceAttachment) String() string {
+	return "NATNetworkDeviceAttachment"
+}
+
 var _ NetworkDeviceAttachment = (*NATNetworkDeviceAttachment)(nil)
 
 // NewNATNetworkDeviceAttachment creates a new NATNetworkDeviceAttachment.
@@ -127,6 +130,10 @@ type BridgedNetworkDeviceAttachment struct {
 	*baseNetworkDeviceAttachment
 }
 
+func (*BridgedNetworkDeviceAttachment) String() string {
+	return "BridgedNetworkDeviceAttachment"
+}
+
 var _ NetworkDeviceAttachment = (*BridgedNetworkDeviceAttachment)(nil)
 
 // NewBridgedNetworkDeviceAttachment creates a new BridgedNetworkDeviceAttachment with networkInterface.
@@ -164,6 +171,10 @@ type FileHandleNetworkDeviceAttachment struct {
 	mtu int
 }
 
+func (*FileHandleNetworkDeviceAttachment) String() string {
+	return "FileHandleNetworkDeviceAttachment"
+}
+
 var _ NetworkDeviceAttachment = (*FileHandleNetworkDeviceAttachment)(nil)
 
 // NewFileHandleNetworkDeviceAttachment initialize the attachment with a file handle.
@@ -253,7 +264,7 @@ func (f *FileHandleNetworkDeviceAttachment) MaximumTransmissionUnit() int {
 // see: https://developer.apple.com/documentation/virtualization/vznetworkdeviceattachment?language=objc
 type NetworkDeviceAttachment interface {
 	objc.NSObject
-
+	fmt.Stringer
 	networkDeviceAttachment()
 }
 
@@ -271,6 +282,8 @@ func (*baseNetworkDeviceAttachment) networkDeviceAttachment() {}
 // see: https://developer.apple.com/documentation/virtualization/vzvirtionetworkdeviceconfiguration?language=objc
 type VirtioNetworkDeviceConfiguration struct {
 	*pointer
+
+	attachment NetworkDeviceAttachment
 }
 
 // NewVirtioNetworkDeviceConfiguration creates a new VirtioNetworkDeviceConfiguration with NetworkDeviceAttachment.
@@ -282,27 +295,31 @@ func NewVirtioNetworkDeviceConfiguration(attachment NetworkDeviceAttachment) (*V
 		return nil, err
 	}
 
-	config := newVirtioNetworkDeviceConfiguration(
-		C.newVZVirtioNetworkDeviceConfiguration(
-			objc.Ptr(attachment),
-		),
-	)
+	config := newVirtioNetworkDeviceConfiguration(attachment)
 	objc.SetFinalizer(config, func(self *VirtioNetworkDeviceConfiguration) {
 		objc.Release(self)
 	})
 	return config, nil
 }
 
-func newVirtioNetworkDeviceConfiguration(ptr unsafe.Pointer) *VirtioNetworkDeviceConfiguration {
+func newVirtioNetworkDeviceConfiguration(attachment NetworkDeviceAttachment) *VirtioNetworkDeviceConfiguration {
+	ptr := C.newVZVirtioNetworkDeviceConfiguration(
+		objc.Ptr(attachment),
+	)
 	return &VirtioNetworkDeviceConfiguration{
-		pointer: objc.NewPointer(ptr),
+		pointer:    objc.NewPointer(ptr),
+		attachment: attachment,
 	}
 }
 
 func (v *VirtioNetworkDeviceConfiguration) SetMACAddress(macAddress *MACAddress) {
 	C.setNetworkDevicesVZMACAddress(objc.Ptr(v), objc.Ptr(macAddress))
 }
 
+func (v *VirtioNetworkDeviceConfiguration) Attachment() NetworkDeviceAttachment {
+	return v.attachment
+}
+
 // MACAddress represents a media access control address (MAC address), the 48-bit ethernet address.
 // see: https://developer.apple.com/documentation/virtualization/vzmacaddress?language=objc
 type MACAddress struct {

virtualization.go

@@ -9,12 +9,14 @@ package vz
 */
 import "C"
 import (
+	"fmt"
 	"runtime/cgo"
 	"sync"
 	"unsafe"
 
 	infinity "github.com/Code-Hex/go-infinity-channel"
 	"github.com/Code-Hex/vz/v3/internal/objc"
+	"github.com/Code-Hex/vz/v3/internal/sliceutil"
 )
 
 // VirtualMachineState represents execution state of the virtual machine.
@@ -91,9 +93,15 @@ type VirtualMachine struct {
 	dispatchQueue unsafe.Pointer
 	machineState  *machineState
 
+	disconnectedIn        *infinity.Channel[*disconnected]
+	disconnectedOut       *infinity.Channel[*DisconnectedError]
+	watchDisconnectedOnce sync.Once
+
 	finalizeOnce sync.Once
 
 	config *VirtualMachineConfiguration
+
+	mu sync.RWMutex
 }
 
 type machineState struct {
@@ -123,20 +131,27 @@ func NewVirtualMachine(config *VirtualMachineConfiguration) (*VirtualMachine, er
 		state:       VirtualMachineState(0),
 		stateNotify: infinity.NewChannel[VirtualMachineState](),
 	}
-
 	stateHandle := cgo.NewHandle(machineState)
+
+	disconnectedIn := infinity.NewChannel[*disconnected]()
+	disconnectedOut := infinity.NewChannel[*DisconnectedError]()
+	disconnectedHandle := cgo.NewHandle(disconnectedIn)
+
 	v := &VirtualMachine{
 		id: cs.String(),
 		pointer: objc.NewPointer(
 			C.newVZVirtualMachineWithDispatchQueue(
 				objc.Ptr(config),
 				dispatchQueue,
 				C.uintptr_t(stateHandle),
+				C.uintptr_t(disconnectedHandle),
 			),
 		),
-		dispatchQueue: dispatchQueue,
-		machineState:  machineState,
-		config:        config,
+		dispatchQueue:   dispatchQueue,
+		machineState:    machineState,
+		disconnectedIn:  disconnectedIn,
+		disconnectedOut: disconnectedOut,
+		config:          config,
 	}
 
 	objc.SetFinalizer(v, func(self *VirtualMachine) {
@@ -357,3 +372,83 @@ func (v *VirtualMachine) StartGraphicApplication(width, height float64) error {
 	C.startVirtualMachineWindow(objc.Ptr(v), C.double(width), C.double(height))
 	return nil
 }
+
+// DisconnectedError represents an error that occurs when a VM’s network attachment is disconnected
+// due to a network-related issue. This error is triggered by the framework when such a disconnection happens.
+type DisconnectedError struct {
+	// Err is the underlying error that caused the disconnection, triggered by the framework.
+	// This error provides information on why the network attachment was disconnected.
+	Err error
+	// The network device configuration associated with the disconnection event.
+	// This configuration helps identify which network device experienced the disconnection.
+	// If Config is nil, the specific configuration details are unavailable.
+	Config *VirtioNetworkDeviceConfiguration
+}
+
+func (e *DisconnectedError) Unwrap() error { return e.Err }
+func (e *DisconnectedError) Error() string {
+	if e.Config == nil {
+		return e.Err.Error()
+	}
+	return fmt.Sprintf("%s: %v", e.Config.attachment, e.Err)
+}
+
+type disconnected struct {
+	err   error
+	index int
+}
+
+// NetworkDeviceAttachmentWasDisconnected returns a receive channel.
+// The channel emits an error message each time the network attachment is disconnected,
+// typically triggered by events such as failure to start, initial boot, device reset, or reboot.
+// As a result, this method may be invoked multiple times throughout the virtual machine's lifecycle.
+//
+// This is only supported on macOS 12 and newer, error will be returned on older versions.
+func (v *VirtualMachine) NetworkDeviceAttachmentWasDisconnected() (<-chan *DisconnectedError, error) {
+	if err := macOSAvailable(12); err != nil {
+		return nil, err
+	}
+	v.watchDisconnectedOnce.Do(func() {
+		go v.watchDisconnected()
+	})
+	return v.disconnectedOut.Out(), nil
+}
+
+// TODO(codehex): refactoring to leave using machineState's mutex lock.
+func (v *VirtualMachine) watchDisconnected() {
+	for disconnected := range v.disconnectedIn.Out() {
+		v.mu.RLock()
+		config := sliceutil.FindValueByIndex(
+			v.config.networkDeviceConfiguration,
+			disconnected.index,
+		)
+		v.mu.RUnlock()
+		v.disconnectedOut.In() <- &DisconnectedError{
+			Err:    disconnected.err,
+			Config: config,
+		}
+	}
+	v.disconnectedOut.Close()
+}
+
+//export emitAttachmentWasDisconnected
+func emitAttachmentWasDisconnected(index C.int, errPtr unsafe.Pointer, cgoHandleUintptr C.uintptr_t) {
+	handler := cgo.Handle(cgoHandleUintptr)
+	err := newNSError(errPtr)
+	// I expected it will not cause panic.
+	// if caused panic, that's unexpected behavior.
+	ch, _ := handler.Value().(*infinity.Channel[*disconnected])
+	ch.In() <- &disconnected{
+		err:   err,
+		index: int(index),
+	}
+}
+
+//export closeAttachmentWasDisconnectedChannel
+func closeAttachmentWasDisconnectedChannel(cgoHandleUintptr C.uintptr_t) {
+	handler := cgo.Handle(cgoHandleUintptr)
+	// I expected it will not cause panic.
+	// if caused panic, that's unexpected behavior.
+	ch, _ := handler.Value().(*infinity.Channel[*disconnected])
+	ch.Close()
+}

virtualization_11.h

@@ -8,12 +8,13 @@
 
 #import "virtualization_helper.h"
 #import <Virtualization/Virtualization.h>
-#import <sys/utsname.h>
 
 /* exported from cgo */
 void connectionHandler(void *connection, void *err, uintptr_t cgoHandle);
 void changeStateOnObserver(int state, uintptr_t cgoHandle);
 bool shouldAcceptNewConnectionHandler(uintptr_t cgoHandle, void *connection, void *socketDevice);
+void emitAttachmentWasDisconnected(int index, void *err, uintptr_t cgoHandle);
+void closeAttachmentWasDisconnectedChannel(uintptr_t cgoHandle);
 
 @interface Observer : NSObject
 - (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context;
@@ -38,11 +39,14 @@ bool shouldAcceptNewConnectionHandler(uintptr_t cgoHandle, void *connection, voi
 - (void)dealloc;
 @end
 
-@interface VZVirtualMachineNetworkDeviceErrorHandler : NSObject <VZVirtualMachineDelegate>
+@interface NetworkDeviceDisconnectedHandler : NSObject <VZVirtualMachineDelegate>
 - (instancetype)initWithHandle:(uintptr_t)cgoHandle;
 - (void)virtualMachine:(VZVirtualMachine *)virtualMachine
                          networkDevice:(VZNetworkDevice *)networkDevice
     attachmentWasDisconnectedWithError:(NSError *)error API_AVAILABLE(macos(12.0));
+- (int)networkDevices:(NSArray<VZNetworkDevice *> *)networkDevices
+              indexOf:(VZNetworkDevice *)networkDevice;
+- (void)dealloc;
 @end
 
 /* VZVirtioSocketListener */
@@ -108,7 +112,7 @@ void VZVirtioSocketDevice_removeSocketListenerForPort(void *socketDevice, void *
 void VZVirtioSocketDevice_connectToPort(void *socketDevice, void *vmQueue, uint32_t port, uintptr_t cgoHandle);
 
 /* VirtualMachine */
-void *newVZVirtualMachineWithDispatchQueue(void *config, void *queue, uintptr_t statusUpdateCgoHandle);
+void *newVZVirtualMachineWithDispatchQueue(void *config, void *queue, uintptr_t statusUpdateCgoHandle, uintptr_t disconnectedCgoHandle);
 bool requestStopVirtualMachine(void *machine, void *queue, void **error);
 void startWithCompletionHandler(void *machine, void *queue, uintptr_t cgoHandle);
 void pauseWithCompletionHandler(void *machine, void *queue, uintptr_t cgoHandle);