dsf-gdb/org.eclipse.cdt.dsf.gdb/src/org/eclipse/cdt/dsf/gdb/service/GDBRunControl_7_0.java - cdt/org.eclipse.cdt - Git at Google

 /*******************************************************************************
  * Copyright (c) 2008, 2015 Wind River Systems and others.
  *
  * This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License 2.0
  * which accompanies this distribution, and is available at
  * https://www.eclipse.org/legal/epl-2.0/
  *
  * SPDX-License-Identifier: EPL-2.0
  *
  * Contributors:
  *     Wind River Systems - initial API and implementation
  *     Ericsson		      - Modified for additional functionality
  *     Ericsson           - Version 7.0
  *     Nokia              - create and use backend service.
  *     Ericsson           - Added IReverseControl support
  *     Marc Khouzam (Ericsson) - Added IReverseModeChangedDMEvent (Bug 399163)
  *     Marc Khouzam (Ericsson) - Started inheriting from GDBRunControl (Bug 405123)
  *     Intel Corporation - Added Reverse Debugging BTrace support
  *******************************************************************************/

 package org.eclipse.cdt.dsf.gdb.service;

 import java.util.Hashtable;

 import org.eclipse.cdt.dsf.concurrent.DataRequestMonitor;
 import org.eclipse.cdt.dsf.concurrent.ImmediateRequestMonitor;
 import org.eclipse.cdt.dsf.concurrent.RequestMonitor;
 import org.eclipse.cdt.dsf.datamodel.AbstractDMEvent;
 import org.eclipse.cdt.dsf.datamodel.DMContexts;
 import org.eclipse.cdt.dsf.datamodel.IDMContext;
 import org.eclipse.cdt.dsf.debug.service.IRunControl;
 import org.eclipse.cdt.dsf.debug.service.IRunControl2;
 import org.eclipse.cdt.dsf.debug.service.IStack.IFrameDMContext;
 import org.eclipse.cdt.dsf.debug.service.command.ICommand;
 import org.eclipse.cdt.dsf.debug.service.command.ICommandControlService.ICommandControlDMContext;
 import org.eclipse.cdt.dsf.gdb.internal.GdbPlugin;
 import org.eclipse.cdt.dsf.gdb.service.IGDBTraceControl.ITraceRecordSelectedChangedDMEvent;
 import org.eclipse.cdt.dsf.mi.service.IMICommandControl;
 import org.eclipse.cdt.dsf.mi.service.IMIExecutionDMContext;
 import org.eclipse.cdt.dsf.mi.service.IMIProcesses;
 import org.eclipse.cdt.dsf.mi.service.IMIRunControl;
 import org.eclipse.cdt.dsf.mi.service.MIRunControl;
 import org.eclipse.cdt.dsf.mi.service.MIStack;
 import org.eclipse.cdt.dsf.mi.service.command.CommandFactory;
 import org.eclipse.cdt.dsf.mi.service.command.output.MIInfo;
 import org.eclipse.cdt.dsf.service.DsfServiceEventHandler;
 import org.eclipse.cdt.dsf.service.DsfSession;
 import org.eclipse.core.runtime.IStatus;
 import org.eclipse.core.runtime.Status;

 public class GDBRunControl_7_0 extends GDBRunControl implements IReverseRunControl {

 	/** @since 4.2 */
 	protected static class GdbReverseModeChangedDMEvent extends AbstractDMEvent<ICommandControlDMContext>
 			implements IReverseModeChangedDMEvent {
 		private boolean fIsEnabled;

 		public GdbReverseModeChangedDMEvent(ICommandControlDMContext context, boolean enabled) {
 			super(context);
 			fIsEnabled = enabled;
 		}

 		@Override
 		public boolean isReverseModeEnabled() {
 			return fIsEnabled;
 		}
 	}

 	private IMICommandControl fCommandControl;
 	private IGDBBackend fGdb;
 	private IMIProcesses fProcService;
 	private CommandFactory fCommandFactory;

 	private boolean fReverseSupported = true;
 	private boolean fReverseStepping = false;
 	private boolean fReverseModeEnabled = false;

 	/**
 	 * This variable allows us to know if run control operation
 	 * should be enabled or disabled.  Run control operations are
 	 * always enabled except when dealing with post-mortem debug
 	 * session, or when visualizing tracepoints.
 	 */
 	private boolean fRunControlOperationsEnabled = true;

 	/**
 	 * Indicates if reverse debugging is supported for the currend debug session.
 	 * @since 5.0
 	 */
 	public boolean getReverseSupported() {
 		return fReverseSupported;
 	}

 	public GDBRunControl_7_0(DsfSession session) {
 		super(session);
 	}

 	@Override
 	public void initialize(final RequestMonitor requestMonitor) {
 		super.initialize(new ImmediateRequestMonitor(requestMonitor) {
 			@Override
 			public void handleSuccess() {
 				doInitialize(requestMonitor);
 			}
 		});
 	}

 	private void doInitialize(final RequestMonitor requestMonitor) {

 		fGdb = getServicesTracker().getService(IGDBBackend.class);
 		fProcService = getServicesTracker().getService(IMIProcesses.class);
 		fCommandControl = getServicesTracker().getService(IMICommandControl.class);
 		fCommandFactory = fCommandControl.getCommandFactory();

 		if (fGdb.getSessionType() == SessionType.CORE) {
 			// No execution for core files, so no support for reverse
 			fRunControlOperationsEnabled = false;
 			fReverseSupported = false;
 		}

 		register(new String[] { IRunControl.class.getName(), IRunControl2.class.getName(),
 				IMIRunControl.class.getName(), MIRunControl.class.getName(), IReverseRunControl.class.getName(),
 				GDBRunControl.class.getName(), GDBRunControl_7_0.class.getName() }, new Hashtable<String, String>());
 		requestMonitor.done();
 	}

 	@Override
 	public void shutdown(final RequestMonitor requestMonitor) {
 		unregister();
 		super.shutdown(requestMonitor);
 	}

 	@Override
 	protected boolean runControlOperationsEnabled() {
 		return fRunControlOperationsEnabled;
 	}

 	@Override
 	public void suspend(IExecutionDMContext context, final RequestMonitor rm) {
 		canSuspend(context, new DataRequestMonitor<Boolean>(getExecutor(), rm) {
 			@Override
 			protected void handleSuccess() {
 				if (getData()) {
 					fGdb.interruptAndWait(getInterruptTimeout(), rm);
 				} else {
 					rm.setStatus(new Status(IStatus.ERROR, GdbPlugin.PLUGIN_ID, INVALID_STATE,
 							"Context cannot be suspended.", null)); //$NON-NLS-1$
 					rm.done();
 				}
 			}
 		});
 	}

 	@Override
 	public void getExecutionContexts(IContainerDMContext containerDmc,
 			final DataRequestMonitor<IExecutionDMContext[]> rm) {
 		fProcService.getProcessesBeingDebugged(containerDmc, new DataRequestMonitor<IDMContext[]>(getExecutor(), rm) {
 			@Override
 			protected void handleSuccess() {
 				if (getData() instanceof IExecutionDMContext[]) {
 					IExecutionDMContext[] execDmcs = (IExecutionDMContext[]) getData();
 					rm.setData(execDmcs);
 				} else {
 					rm.setStatus(
 							new Status(IStatus.ERROR, GdbPlugin.PLUGIN_ID, INTERNAL_ERROR, "Invalid contexts", null)); //$NON-NLS-1$
 				}
 				rm.done();
 			}
 		});
 	}

 	/** @since 2.0 */
 	@Override
 	public void canReverseResume(IExecutionDMContext context, DataRequestMonitor<Boolean> rm) {
 		if (!runControlOperationsEnabled()) {
 			rm.setData(false);
 			rm.done();
 			return;
 		}

 		rm.setData(fReverseModeEnabled && doCanResume(context));
 		rm.done();
 	}

 	/** @since 2.0 */
 	@Override
 	public void canReverseStep(final IExecutionDMContext context, StepType stepType,
 			final DataRequestMonitor<Boolean> rm) {
 		if (!runControlOperationsEnabled()) {
 			rm.setData(false);
 			rm.done();
 			return;
 		}

 		if (context instanceof IContainerDMContext) {
 			rm.setData(false);
 			rm.done();
 			return;
 		}

 		if (stepType == StepType.STEP_RETURN) {

 			// Check the stuff we know first, before going to the backend for
 			// stack info
 			if (!fReverseModeEnabled || !doCanResume(context)) {
 				rm.setData(false);
 				rm.done();
 				return;
 			}

 			// A step return will always be done in the top stack frame.
 			// If the top stack frame is the only stack frame, it does not make sense
 			// to do a step return since GDB will reject it.
 			MIStack stackService = getServicesTracker().getService(MIStack.class);
 			if (stackService != null) {
 				// Check that the stack is at least two deep.
 				stackService.getStackDepth(context, 2, new DataRequestMonitor<Integer>(getExecutor(), rm) {
 					@Override
 					public void handleCompleted() {
 						if (isSuccess() && getData() == 1) {
 							rm.setData(false);
 							rm.done();
 						} else {
 							canReverseResume(context, rm);
 						}
 					}
 				});
 				return;
 			}
 		}

 		canReverseResume(context, rm);
 	}

 	/** @since 2.0 */
 	@Override
 	public boolean isReverseStepping(IExecutionDMContext context) {
 		return !isTerminated() && fReverseStepping;
 	}

 	/** @since 2.0 */
 	@Override
 	public void reverseResume(final IExecutionDMContext context, final RequestMonitor rm) {
 		if (fReverseModeEnabled && doCanResume(context)) {
 			ICommand<MIInfo> cmd = null;
 			if (context instanceof IContainerDMContext) {
 				cmd = fCommandFactory.createMIExecReverseContinue(context);
 			} else {
 				IMIExecutionDMContext dmc = DMContexts.getAncestorOfType(context, IMIExecutionDMContext.class);
 				if (dmc == null) {
 					rm.setStatus(new Status(IStatus.ERROR, GdbPlugin.PLUGIN_ID, INVALID_STATE,
 							"Given context: " + context + " is not an execution context.", null)); //$NON-NLS-1$ //$NON-NLS-2$
 					rm.done();
 					return;
 				}
 				cmd = fCommandFactory.createMIExecReverseContinue(dmc);
 			}

 			setResumePending(true);
 			// Cygwin GDB will accept commands and execute them after the step
 			// which is not what we want, so mark the target as unavailable
 			// as soon as we send a resume command.
 			getCache().setContextAvailable(context, false);

 			getConnection().queueCommand(cmd, new DataRequestMonitor<MIInfo>(getExecutor(), rm) {
 				@Override
 				public void handleFailure() {
 					setResumePending(false);
 					getCache().setContextAvailable(context, true);
 				}
 			});
 		} else {
 			rm.setStatus(new Status(IStatus.ERROR, GdbPlugin.PLUGIN_ID, INVALID_STATE,
 					"Given context: " + context + ", is already running or reverse not enabled.", null)); //$NON-NLS-1$ //$NON-NLS-2$
 			rm.done();
 		}

 	}

 	/** @since 2.0 */
 	@Override
 	public void reverseStep(final IExecutionDMContext context, StepType stepType, final RequestMonitor rm) {
 		assert context != null;

 		IMIExecutionDMContext dmc = DMContexts.getAncestorOfType(context, IMIExecutionDMContext.class);
 		if (dmc == null) {
 			rm.setStatus(new Status(IStatus.ERROR, GdbPlugin.PLUGIN_ID, NOT_SUPPORTED,
 					"Given context: " + context + " is not an execution context.", null)); //$NON-NLS-1$ //$NON-NLS-2$
 			rm.done();
 			return;
 		}

 		if (!fReverseModeEnabled || !doCanResume(context)) {
 			rm.setStatus(new Status(IStatus.ERROR, GdbPlugin.PLUGIN_ID, INVALID_STATE, "Cannot resume context", null)); //$NON-NLS-1$
 			rm.done();
 			return;
 		}

 		ICommand<MIInfo> cmd = null;
 		switch (stepType) {
 		case STEP_INTO:
 			cmd = fCommandFactory.createMIExecReverseStep(dmc, 1);
 			break;
 		case STEP_OVER:
 			cmd = fCommandFactory.createMIExecReverseNext(dmc, 1);
 			break;
 		case STEP_RETURN:
 			// The -exec-finish command operates on the selected stack frame, but here we always
 			// want it to operate on the top stack frame.  So we manually create a top-frame
 			// context to use with the MI command.
 			// We get a local instance of the stack service because the stack service can be shut
 			// down before the run control service is shut down.  So it is possible for the
 			// getService() request below to return null.
 			MIStack stackService = getServicesTracker().getService(MIStack.class);
 			if (stackService != null) {
 				IFrameDMContext topFrameDmc = stackService.createFrameDMContext(dmc, 0);
 				cmd = fCommandFactory.createMIExecUncall(topFrameDmc);
 			} else {
 				rm.setStatus(new Status(IStatus.ERROR, GdbPlugin.PLUGIN_ID, NOT_SUPPORTED,
 						"Cannot create context for command, stack service not available.", null)); //$NON-NLS-1$
 				rm.done();
 				return;
 			}
 			break;
 		case INSTRUCTION_STEP_INTO:
 			cmd = fCommandFactory.createMIExecReverseStepInstruction(dmc, 1);
 			break;
 		case INSTRUCTION_STEP_OVER:
 			cmd = fCommandFactory.createMIExecReverseNextInstruction(dmc, 1);
 			break;
 		default:
 			rm.setStatus(new Status(IStatus.ERROR, GdbPlugin.PLUGIN_ID, INTERNAL_ERROR, "Given step type not supported", //$NON-NLS-1$
 					null));
 			rm.done();
 			return;
 		}

 		setResumePending(true);
 		fReverseStepping = true;
 		getCache().setContextAvailable(context, false);

 		getConnection().queueCommand(cmd, new DataRequestMonitor<MIInfo>(getExecutor(), rm) {
 			@Override
 			public void handleFailure() {
 				setResumePending(false);
 				fReverseStepping = false;
 				getCache().setContextAvailable(context, true);
 			}
 		});
 	}

 	/** @since 2.0 */
 	@Override
 	public void canEnableReverseMode(ICommandControlDMContext context, DataRequestMonitor<Boolean> rm) {
 		rm.setData(fReverseSupported);
 		rm.done();
 	}

 	/** @since 2.0 */
 	@Override
 	public void isReverseModeEnabled(ICommandControlDMContext context, DataRequestMonitor<Boolean> rm) {
 		rm.setData(fReverseModeEnabled);
 		rm.done();
 	}

 	/** @since 2.0 */
 	@Override
 	public void enableReverseMode(ICommandControlDMContext context, final boolean enable, final RequestMonitor rm) {
 		if (!fReverseSupported) {
 			rm.setStatus(new Status(IStatus.ERROR, GdbPlugin.PLUGIN_ID, NOT_SUPPORTED, "Reverse mode is not supported.", //$NON-NLS-1$
 					null));
 			rm.done();
 			return;
 		}

 		if (fReverseModeEnabled == enable) {
 			rm.done();
 			return;
 		}

 		getConnection().queueCommand(fCommandFactory.createCLIRecord(context, enable),
 				new DataRequestMonitor<MIInfo>(getExecutor(), rm) {
 					@Override
 					public void handleSuccess() {
 						setReverseModeEnabled(enable);
 						rm.done();
 					}
 				});
 	}

 	// Overridden to use the new MI command -exec-jump
 	/** @since 3.0 */
 	@Override
 	public void resumeAtLocation(IExecutionDMContext context, String location, RequestMonitor rm) {
 		assert context != null;

 		final IMIExecutionDMContext dmc = DMContexts.getAncestorOfType(context, IMIExecutionDMContext.class);
 		if (dmc == null) {
 			rm.setStatus(new Status(IStatus.ERROR, GdbPlugin.PLUGIN_ID, INTERNAL_ERROR,
 					"Given context: " + context + " is not an thread execution context.", null)); //$NON-NLS-1$  //$NON-NLS-2$
 			rm.done();
 			return;
 		}

 		if (doCanResume(dmc)) {
 			setResumePending(true);
 			getCache().setContextAvailable(dmc, false);
 			getConnection().queueCommand(
 					// The MI command -exec-jump was added in GDB 7.0
 					fCommandFactory.createMIExecJump(dmc, location), new DataRequestMonitor<MIInfo>(getExecutor(), rm) {
 						@Override
 						protected void handleFailure() {
 							setResumePending(false);
 							getCache().setContextAvailable(dmc, true);

 							super.handleFailure();
 						}
 					});
 		} else {
 			rm.setStatus(
 					new Status(IStatus.ERROR, GdbPlugin.PLUGIN_ID, NOT_SUPPORTED, "Cannot resume given DMC.", null)); //$NON-NLS-1$
 			rm.done();
 		}
 	}

 	/**
 	 * @since 3.0
 	 */
 	@DsfServiceEventHandler
 	public void eventDispatched(ITraceRecordSelectedChangedDMEvent e) {
 		if (e.isVisualizationModeEnabled()) {
 			// We have started looking at trace records.  We can no longer
 			// do run control operations.
 			fRunControlOperationsEnabled = false;
 		} else {
 			// We stopped looking at trace data and gone back to debugger mode
 			fRunControlOperationsEnabled = true;
 		}
 	}

 	/** @since 2.0 */
 	public void setReverseModeEnabled(boolean enabled) {
 		if (fReverseModeEnabled != enabled) {
 			fReverseModeEnabled = enabled;
 			getSession().dispatchEvent(
 					new GdbReverseModeChangedDMEvent(fCommandControl.getContext(), fReverseModeEnabled),
 					getProperties());
 		}
 	}
 }
	/*******************************************************************************
	* Copyright (c) 2008, 2015 Wind River Systems and others.
	*
	* This program and the accompanying materials
	* are made available under the terms of the Eclipse Public License 2.0
	* which accompanies this distribution, and is available at
	* https://www.eclipse.org/legal/epl-2.0/
	*
	* SPDX-License-Identifier: EPL-2.0
	*
	* Contributors:
	* Wind River Systems - initial API and implementation
	* Ericsson - Modified for additional functionality
	* Ericsson - Version 7.0
	* Nokia - create and use backend service.
	* Ericsson - Added IReverseControl support
	* Marc Khouzam (Ericsson) - Added IReverseModeChangedDMEvent (Bug 399163)
	* Marc Khouzam (Ericsson) - Started inheriting from GDBRunControl (Bug 405123)
	* Intel Corporation - Added Reverse Debugging BTrace support
	*******************************************************************************/

	package org.eclipse.cdt.dsf.gdb.service;

	import java.util.Hashtable;

	import org.eclipse.cdt.dsf.concurrent.DataRequestMonitor;
	import org.eclipse.cdt.dsf.concurrent.ImmediateRequestMonitor;
	import org.eclipse.cdt.dsf.concurrent.RequestMonitor;
	import org.eclipse.cdt.dsf.datamodel.AbstractDMEvent;
	import org.eclipse.cdt.dsf.datamodel.DMContexts;
	import org.eclipse.cdt.dsf.datamodel.IDMContext;
	import org.eclipse.cdt.dsf.debug.service.IRunControl;
	import org.eclipse.cdt.dsf.debug.service.IRunControl2;
	import org.eclipse.cdt.dsf.debug.service.IStack.IFrameDMContext;
	import org.eclipse.cdt.dsf.debug.service.command.ICommand;
	import org.eclipse.cdt.dsf.debug.service.command.ICommandControlService.ICommandControlDMContext;
	import org.eclipse.cdt.dsf.gdb.internal.GdbPlugin;
	import org.eclipse.cdt.dsf.gdb.service.IGDBTraceControl.ITraceRecordSelectedChangedDMEvent;
	import org.eclipse.cdt.dsf.mi.service.IMICommandControl;
	import org.eclipse.cdt.dsf.mi.service.IMIExecutionDMContext;
	import org.eclipse.cdt.dsf.mi.service.IMIProcesses;
	import org.eclipse.cdt.dsf.mi.service.IMIRunControl;
	import org.eclipse.cdt.dsf.mi.service.MIRunControl;
	import org.eclipse.cdt.dsf.mi.service.MIStack;
	import org.eclipse.cdt.dsf.mi.service.command.CommandFactory;
	import org.eclipse.cdt.dsf.mi.service.command.output.MIInfo;
	import org.eclipse.cdt.dsf.service.DsfServiceEventHandler;
	import org.eclipse.cdt.dsf.service.DsfSession;
	import org.eclipse.core.runtime.IStatus;
	import org.eclipse.core.runtime.Status;

	public class GDBRunControl_7_0 extends GDBRunControl implements IReverseRunControl {

	/** @since 4.2 */
	protected static class GdbReverseModeChangedDMEvent extends AbstractDMEvent<ICommandControlDMContext>
	implements IReverseModeChangedDMEvent {
	private boolean fIsEnabled;

	public GdbReverseModeChangedDMEvent(ICommandControlDMContext context, boolean enabled) {
	super(context);
	fIsEnabled = enabled;
	}

	@Override
	public boolean isReverseModeEnabled() {
	return fIsEnabled;
	}
	}

	private IMICommandControl fCommandControl;
	private IGDBBackend fGdb;
	private IMIProcesses fProcService;
	private CommandFactory fCommandFactory;

	private boolean fReverseSupported = true;
	private boolean fReverseStepping = false;
	private boolean fReverseModeEnabled = false;

	/**
	* This variable allows us to know if run control operation
	* should be enabled or disabled. Run control operations are
	* always enabled except when dealing with post-mortem debug
	* session, or when visualizing tracepoints.
	*/
	private boolean fRunControlOperationsEnabled = true;

	/**
	* Indicates if reverse debugging is supported for the currend debug session.
	* @since 5.0
	*/
	public boolean getReverseSupported() {
	return fReverseSupported;
	}

	public GDBRunControl_7_0(DsfSession session) {
	super(session);
	}

	@Override
	public void initialize(final RequestMonitor requestMonitor) {
	super.initialize(new ImmediateRequestMonitor(requestMonitor) {
	@Override
	public void handleSuccess() {
	doInitialize(requestMonitor);
	}
	});
	}

	private void doInitialize(final RequestMonitor requestMonitor) {

	fGdb = getServicesTracker().getService(IGDBBackend.class);
	fProcService = getServicesTracker().getService(IMIProcesses.class);
	fCommandControl = getServicesTracker().getService(IMICommandControl.class);
	fCommandFactory = fCommandControl.getCommandFactory();

	if (fGdb.getSessionType() == SessionType.CORE) {
	// No execution for core files, so no support for reverse
	fRunControlOperationsEnabled = false;
	fReverseSupported = false;
	}

	register(new String[] { IRunControl.class.getName(), IRunControl2.class.getName(),
	IMIRunControl.class.getName(), MIRunControl.class.getName(), IReverseRunControl.class.getName(),
	GDBRunControl.class.getName(), GDBRunControl_7_0.class.getName() }, new Hashtable<String, String>());
	requestMonitor.done();
	}

	@Override
	public void shutdown(final RequestMonitor requestMonitor) {
	unregister();
	super.shutdown(requestMonitor);
	}

	@Override
	protected boolean runControlOperationsEnabled() {
	return fRunControlOperationsEnabled;
	}

	@Override
	public void suspend(IExecutionDMContext context, final RequestMonitor rm) {
	canSuspend(context, new DataRequestMonitor<Boolean>(getExecutor(), rm) {
	@Override
	protected void handleSuccess() {
	if (getData()) {
	fGdb.interruptAndWait(getInterruptTimeout(), rm);
	} else {
	rm.setStatus(new Status(IStatus.ERROR, GdbPlugin.PLUGIN_ID, INVALID_STATE,
	"Context cannot be suspended.", null)); //$NON-NLS-1$
	rm.done();
	}
	}
	});
	}

	@Override
	public void getExecutionContexts(IContainerDMContext containerDmc,
	final DataRequestMonitor<IExecutionDMContext[]> rm) {
	fProcService.getProcessesBeingDebugged(containerDmc, new DataRequestMonitor<IDMContext[]>(getExecutor(), rm) {
	@Override
	protected void handleSuccess() {
	if (getData() instanceof IExecutionDMContext[]) {
	IExecutionDMContext[] execDmcs = (IExecutionDMContext[]) getData();
	rm.setData(execDmcs);
	} else {
	rm.setStatus(
	new Status(IStatus.ERROR, GdbPlugin.PLUGIN_ID, INTERNAL_ERROR, "Invalid contexts", null)); //$NON-NLS-1$
	}
	rm.done();
	}
	});
	}

	/** @since 2.0 */
	@Override
	public void canReverseResume(IExecutionDMContext context, DataRequestMonitor<Boolean> rm) {
	if (!runControlOperationsEnabled()) {
	rm.setData(false);
	rm.done();
	return;
	}

	rm.setData(fReverseModeEnabled && doCanResume(context));
	rm.done();
	}

	/** @since 2.0 */
	@Override
	public void canReverseStep(final IExecutionDMContext context, StepType stepType,
	final DataRequestMonitor<Boolean> rm) {
	if (!runControlOperationsEnabled()) {
	rm.setData(false);
	rm.done();
	return;
	}

	if (context instanceof IContainerDMContext) {
	rm.setData(false);
	rm.done();
	return;
	}

	if (stepType == StepType.STEP_RETURN) {

	// Check the stuff we know first, before going to the backend for
	// stack info
	if (!fReverseModeEnabled \|\| !doCanResume(context)) {
	rm.setData(false);
	rm.done();
	return;
	}

	// A step return will always be done in the top stack frame.
	// If the top stack frame is the only stack frame, it does not make sense
	// to do a step return since GDB will reject it.
	MIStack stackService = getServicesTracker().getService(MIStack.class);
	if (stackService != null) {
	// Check that the stack is at least two deep.
	stackService.getStackDepth(context, 2, new DataRequestMonitor<Integer>(getExecutor(), rm) {
	@Override
	public void handleCompleted() {
	if (isSuccess() && getData() == 1) {
	rm.setData(false);
	rm.done();
	} else {
	canReverseResume(context, rm);
	}
	}
	});
	return;
	}
	}

	canReverseResume(context, rm);
	}

	/** @since 2.0 */
	@Override
	public boolean isReverseStepping(IExecutionDMContext context) {
	return !isTerminated() && fReverseStepping;
	}

	/** @since 2.0 */
	@Override
	public void reverseResume(final IExecutionDMContext context, final RequestMonitor rm) {
	if (fReverseModeEnabled && doCanResume(context)) {
	ICommand<MIInfo> cmd = null;
	if (context instanceof IContainerDMContext) {
	cmd = fCommandFactory.createMIExecReverseContinue(context);
	} else {
	IMIExecutionDMContext dmc = DMContexts.getAncestorOfType(context, IMIExecutionDMContext.class);
	if (dmc == null) {
	rm.setStatus(new Status(IStatus.ERROR, GdbPlugin.PLUGIN_ID, INVALID_STATE,
	"Given context: " + context + " is not an execution context.", null)); //$NON-NLS-1$ //$NON-NLS-2$
	rm.done();
	return;
	}
	cmd = fCommandFactory.createMIExecReverseContinue(dmc);
	}

	setResumePending(true);
	// Cygwin GDB will accept commands and execute them after the step
	// which is not what we want, so mark the target as unavailable
	// as soon as we send a resume command.
	getCache().setContextAvailable(context, false);

	getConnection().queueCommand(cmd, new DataRequestMonitor<MIInfo>(getExecutor(), rm) {
	@Override
	public void handleFailure() {
	setResumePending(false);
	getCache().setContextAvailable(context, true);
	}
	});
	} else {
	rm.setStatus(new Status(IStatus.ERROR, GdbPlugin.PLUGIN_ID, INVALID_STATE,
	"Given context: " + context + ", is already running or reverse not enabled.", null)); //$NON-NLS-1$ //$NON-NLS-2$
	rm.done();
	}

	}

	/** @since 2.0 */
	@Override
	public void reverseStep(final IExecutionDMContext context, StepType stepType, final RequestMonitor rm) {
	assert context != null;

	IMIExecutionDMContext dmc = DMContexts.getAncestorOfType(context, IMIExecutionDMContext.class);
	if (dmc == null) {
	rm.setStatus(new Status(IStatus.ERROR, GdbPlugin.PLUGIN_ID, NOT_SUPPORTED,
	"Given context: " + context + " is not an execution context.", null)); //$NON-NLS-1$ //$NON-NLS-2$
	rm.done();
	return;
	}

	if (!fReverseModeEnabled \|\| !doCanResume(context)) {
	rm.setStatus(new Status(IStatus.ERROR, GdbPlugin.PLUGIN_ID, INVALID_STATE, "Cannot resume context", null)); //$NON-NLS-1$
	rm.done();
	return;
	}

	ICommand<MIInfo> cmd = null;
	switch (stepType) {
	case STEP_INTO:
	cmd = fCommandFactory.createMIExecReverseStep(dmc, 1);
	break;
	case STEP_OVER:
	cmd = fCommandFactory.createMIExecReverseNext(dmc, 1);
	break;
	case STEP_RETURN:
	// The -exec-finish command operates on the selected stack frame, but here we always
	// want it to operate on the top stack frame. So we manually create a top-frame
	// context to use with the MI command.
	// We get a local instance of the stack service because the stack service can be shut
	// down before the run control service is shut down. So it is possible for the
	// getService() request below to return null.
	MIStack stackService = getServicesTracker().getService(MIStack.class);
	if (stackService != null) {
	IFrameDMContext topFrameDmc = stackService.createFrameDMContext(dmc, 0);
	cmd = fCommandFactory.createMIExecUncall(topFrameDmc);
	} else {
	rm.setStatus(new Status(IStatus.ERROR, GdbPlugin.PLUGIN_ID, NOT_SUPPORTED,
	"Cannot create context for command, stack service not available.", null)); //$NON-NLS-1$
	rm.done();
	return;
	}
	break;
	case INSTRUCTION_STEP_INTO:
	cmd = fCommandFactory.createMIExecReverseStepInstruction(dmc, 1);
	break;
	case INSTRUCTION_STEP_OVER:
	cmd = fCommandFactory.createMIExecReverseNextInstruction(dmc, 1);
	break;
	default:
	rm.setStatus(new Status(IStatus.ERROR, GdbPlugin.PLUGIN_ID, INTERNAL_ERROR, "Given step type not supported", //$NON-NLS-1$
	null));
	rm.done();
	return;
	}

	setResumePending(true);
	fReverseStepping = true;
	getCache().setContextAvailable(context, false);

	getConnection().queueCommand(cmd, new DataRequestMonitor<MIInfo>(getExecutor(), rm) {
	@Override
	public void handleFailure() {
	setResumePending(false);
	fReverseStepping = false;
	getCache().setContextAvailable(context, true);
	}
	});
	}

	/** @since 2.0 */
	@Override
	public void canEnableReverseMode(ICommandControlDMContext context, DataRequestMonitor<Boolean> rm) {
	rm.setData(fReverseSupported);
	rm.done();
	}

	/** @since 2.0 */
	@Override
	public void isReverseModeEnabled(ICommandControlDMContext context, DataRequestMonitor<Boolean> rm) {
	rm.setData(fReverseModeEnabled);
	rm.done();
	}

	/** @since 2.0 */
	@Override
	public void enableReverseMode(ICommandControlDMContext context, final boolean enable, final RequestMonitor rm) {
	if (!fReverseSupported) {
	rm.setStatus(new Status(IStatus.ERROR, GdbPlugin.PLUGIN_ID, NOT_SUPPORTED, "Reverse mode is not supported.", //$NON-NLS-1$
	null));
	rm.done();
	return;
	}

	if (fReverseModeEnabled == enable) {
	rm.done();
	return;
	}

	getConnection().queueCommand(fCommandFactory.createCLIRecord(context, enable),
	new DataRequestMonitor<MIInfo>(getExecutor(), rm) {
	@Override
	public void handleSuccess() {
	setReverseModeEnabled(enable);
	rm.done();
	}
	});
	}

	// Overridden to use the new MI command -exec-jump
	/** @since 3.0 */
	@Override
	public void resumeAtLocation(IExecutionDMContext context, String location, RequestMonitor rm) {
	assert context != null;

	final IMIExecutionDMContext dmc = DMContexts.getAncestorOfType(context, IMIExecutionDMContext.class);
	if (dmc == null) {
	rm.setStatus(new Status(IStatus.ERROR, GdbPlugin.PLUGIN_ID, INTERNAL_ERROR,
	"Given context: " + context + " is not an thread execution context.", null)); //$NON-NLS-1$ //$NON-NLS-2$
	rm.done();
	return;
	}

	if (doCanResume(dmc)) {
	setResumePending(true);
	getCache().setContextAvailable(dmc, false);
	getConnection().queueCommand(
	// The MI command -exec-jump was added in GDB 7.0
	fCommandFactory.createMIExecJump(dmc, location), new DataRequestMonitor<MIInfo>(getExecutor(), rm) {
	@Override
	protected void handleFailure() {
	setResumePending(false);
	getCache().setContextAvailable(dmc, true);

	super.handleFailure();
	}
	});
	} else {
	rm.setStatus(
	new Status(IStatus.ERROR, GdbPlugin.PLUGIN_ID, NOT_SUPPORTED, "Cannot resume given DMC.", null)); //$NON-NLS-1$
	rm.done();
	}
	}

	/**
	* @since 3.0
	*/
	@DsfServiceEventHandler
	public void eventDispatched(ITraceRecordSelectedChangedDMEvent e) {
	if (e.isVisualizationModeEnabled()) {
	// We have started looking at trace records. We can no longer
	// do run control operations.
	fRunControlOperationsEnabled = false;
	} else {
	// We stopped looking at trace data and gone back to debugger mode
	fRunControlOperationsEnabled = true;
	}
	}

	/** @since 2.0 */
	public void setReverseModeEnabled(boolean enabled) {
	if (fReverseModeEnabled != enabled) {
	fReverseModeEnabled = enabled;
	getSession().dispatchEvent(
	new GdbReverseModeChangedDMEvent(fCommandControl.getContext(), fReverseModeEnabled),
	getProperties());
	}
	}
	}