Support termination of virtual DSPProcess

The DSPProcess not always maps to an actual process, but when it does,
we use it to control termination actions and state, and if it doesn't we
failback to an internal state.

This makes that the "Terminate" button on the Console works.

org.eclipse.lsp4e.debug/src/org/eclipse/lsp4e/debug/console/DSPProcess.java

@@ -11,7 +11,9 @@
 import java.util.Optional;
 
 import org.eclipse.core.runtime.Status;
+import org.eclipse.debug.core.DebugEvent;
 import org.eclipse.debug.core.DebugException;
+import org.eclipse.debug.core.DebugPlugin;
 import org.eclipse.debug.core.ILaunch;
 import org.eclipse.debug.core.model.IProcess;
 import org.eclipse.lsp4e.debug.debugmodel.DSPDebugTarget;
@@ -27,6 +29,7 @@ public class DSPProcess implements IProcess {
 	private final DSPStreamsProxy proxy;
 	private final ProcessEventArguments processArgs;
 	private final Optional<ProcessHandle> handle;
+	private boolean terminated;
 
 	public DSPProcess(DSPDebugTarget target) {
 		this(target, null);
@@ -50,16 +53,19 @@ public <T> T getAdapter(Class<T> adapter) {
 
 	@Override
 	public boolean canTerminate() {
-		return target.canTerminate();
+		return !isTerminated();
 	}
 
 	@Override
 	public boolean isTerminated() {
-		return target.isTerminated();
+		return handle.map(h -> !h.isAlive()).orElse(terminated);
 	}
 
 	@Override
 	public void terminate() throws DebugException {
+		terminated = true;
+		handle.ifPresent(ProcessHandle::destroyForcibly);
+		DebugPlugin.getDefault().fireDebugEventSet(new DebugEvent[] { new DebugEvent(this, DebugEvent.TERMINATE) });
 		target.terminate();
 	}
 

org.eclipse.lsp4e.debug/src/org/eclipse/lsp4e/debug/debugmodel/DSPDebugTarget.java

@@ -310,16 +310,17 @@ private void terminated() {
 			try {
 				t.terminate();
 			} catch (DebugException e) {
-				// TODO Auto-generated catch block
-				e.printStackTrace();
+				DSPPlugin.logError(e);
 			}
 		});
-		fireTerminateEvent();
-		if (process != null) {
-			// Disable the terminate button of the console associated with the DSPProcess.
-			DebugPlugin.getDefault()
-					.fireDebugEventSet(new DebugEvent[] { new DebugEvent(process, DebugEvent.TERMINATE) });
+		if (process != null && process.canTerminate()) {
+			try {
+				process.terminate();
+			} catch (DebugException e) {
+				DSPPlugin.logError(e);
+			}
 		}
+		fireTerminateEvent();
 		if (breakpointManager != null) {
 			breakpointManager.shutdown();
 		}