dsf-gdb/org.eclipse.cdt.dsf.gdb/src/org/eclipse/cdt/dsf/gdb/service/GDBRunControl.java

/*******************************************************************************
 * Copyright (c) 2006, 2016 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 AB		  - Modified for additional functionality
 *     Nokia - create and use backend service.
 *     Alvaro Sanchez-Leon (Ericsson AB) - Support for Step into selection (bug 244865)
 *     Alvaro Sanchez-Leon (Ericsson AB) - Bug 415362
 *******************************************************************************/

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

import java.util.Arrays;
import java.util.Hashtable;
import java.util.Iterator;
import java.util.List;

import org.eclipse.cdt.core.model.IFunctionDeclaration;
import org.eclipse.cdt.dsf.concurrent.DataRequestMonitor;
import org.eclipse.cdt.dsf.concurrent.ImmediateDataRequestMonitor;
import org.eclipse.cdt.dsf.concurrent.ImmediateRequestMonitor;
import org.eclipse.cdt.dsf.concurrent.RequestMonitor;
import org.eclipse.cdt.dsf.datamodel.DMContexts;
import org.eclipse.cdt.dsf.datamodel.IDMContext;
import org.eclipse.cdt.dsf.debug.service.IBreakpoints.IBreakpointsTargetDMContext;
import org.eclipse.cdt.dsf.debug.service.IProcesses.IProcessDMContext;
import org.eclipse.cdt.dsf.debug.service.IProcesses.IThreadDMContext;
import org.eclipse.cdt.dsf.debug.service.IRunControl;
import org.eclipse.cdt.dsf.debug.service.IRunControl2;
import org.eclipse.cdt.dsf.debug.service.IRunControl3;
import org.eclipse.cdt.dsf.debug.service.command.ICommandControlService;
import org.eclipse.cdt.dsf.gdb.internal.GdbPlugin;
import org.eclipse.cdt.dsf.gdb.internal.service.control.StepIntoSelectionActiveOperation;
import org.eclipse.cdt.dsf.gdb.internal.service.control.StepIntoSelectionUtils;
import org.eclipse.cdt.dsf.mi.service.IMICommandControl;
import org.eclipse.cdt.dsf.mi.service.IMIExecutionDMContext;
import org.eclipse.cdt.dsf.mi.service.IMIProcessDMContext;
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.events.MIBreakpointHitEvent;
import org.eclipse.cdt.dsf.mi.service.command.events.MIEvent;
import org.eclipse.cdt.dsf.mi.service.command.events.MIInferiorExitEvent;
import org.eclipse.cdt.dsf.mi.service.command.events.MIRunningEvent;
import org.eclipse.cdt.dsf.mi.service.command.events.MISignalEvent;
import org.eclipse.cdt.dsf.mi.service.command.events.MIStoppedEvent;
import org.eclipse.cdt.dsf.mi.service.command.events.MIThreadExitEvent;
import org.eclipse.cdt.dsf.mi.service.command.output.MIBreakInsertInfo;
import org.eclipse.cdt.dsf.mi.service.command.output.MIFrame;
import org.eclipse.cdt.dsf.mi.service.command.output.MIInfo;
import org.eclipse.cdt.dsf.mi.service.command.output.MIStackInfoDepthInfo;
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.Platform;
import org.eclipse.core.runtime.Status;

public class GDBRunControl extends MIRunControl {

	private static class RunToLineActiveOperation {
		private IMIExecutionDMContext fThreadContext;
		private String fBpId;
		private String fFileLocation;
		private String fAddrLocation;
		private boolean fSkipBreakpoints;

		public RunToLineActiveOperation(IMIExecutionDMContext threadContext, String bpId, String fileLoc, String addr,
				boolean skipBreakpoints) {
			fThreadContext = threadContext;
			fBpId = bpId;
			fFileLocation = fileLoc;
			fAddrLocation = addr;
			fSkipBreakpoints = skipBreakpoints;
		}

		public IMIExecutionDMContext getThreadContext() {
			return fThreadContext;
		}

		public String getBreakointId() {
			return fBpId;
		}

		public String getFileLocation() {
			return fFileLocation;
		}

		public String getAddrLocation() {
			return fAddrLocation;
		}

		public boolean shouldSkipBreakpoints() {
			return fSkipBreakpoints;
		}
	}

	private IGDBBackend fGdb;
	private IMIProcesses fProcService;
	private CommandFactory fCommandFactory;
	private ICommandControlService fConnection;

	// Record list of execution contexts
	private IExecutionDMContext[] fOldExecutionCtxts;

	private RunToLineActiveOperation fRunToLineActiveOperation = null;

	private StepIntoSelectionActiveOperation fStepInToSelectionActiveOperation = null;

	public GDBRunControl(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);
		fCommandFactory = getServicesTracker().getService(IMICommandControl.class).getCommandFactory();
		fConnection = getServicesTracker().getService(ICommandControlService.class);

		register(
				new String[] { IRunControl.class.getName(), IRunControl2.class.getName(), IRunControl3.class.getName(),
						IMIRunControl.class.getName(), MIRunControl.class.getName(), GDBRunControl.class.getName() },
				new Hashtable<String, String>());
		requestMonitor.done();
	}

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

	/**
	 * Allows us to know if run control operations should be
	 * enabled or disabled.  Run control operations are
	 * disabled, for example, when dealing with post-mortem sessions.
	 * @since 4.2
	 */
	protected boolean runControlOperationsEnabled() {
		return fGdb.getSessionType() != SessionType.CORE;
	}

	@Override
	public IMIExecutionDMContext createMIExecutionContext(IContainerDMContext container, String threadId) {
		IProcessDMContext procDmc = DMContexts.getAncestorOfType(container, IProcessDMContext.class);

		IThreadDMContext threadDmc = null;
		if (procDmc != null) {
			// For now, reuse the threadId as the OSThreadId
			threadDmc = fProcService.createThreadContext(procDmc, threadId);
		}

		return fProcService.createExecutionContext(container, threadDmc, threadId);
	}

	@Override
	public void suspend(final IExecutionDMContext context, final RequestMonitor rm) {
		canSuspend(context, new DataRequestMonitor<Boolean>(getExecutor(), rm) {
			@Override
			protected void handleSuccess() {
				if (getData()) {
					int interruptTimeout = getInterruptTimeout();
					// A local Windows attach session requires us to interrupt
					// the inferior instead of gdb. This deficiency was fixed
					// in gdb 7.0. Note that there's a GDBRunControl_7_0,
					// so we're dealing with gdb < 7.0 if we get here.
					// Refer to https://bugs.eclipse.org/bugs/show_bug.cgi?id=304096#c56
					// if you have the stomach for it.
					if (fGdb.getIsAttachSession() && fGdb.getSessionType() != SessionType.REMOTE
							&& Platform.getOS().equals(Platform.OS_WIN32)) {
						IMIProcessDMContext processDmc = DMContexts.getAncestorOfType(context,
								IMIProcessDMContext.class);
						String inferiorPid = processDmc.getProcId();
						if (inferiorPid != null) {
							fGdb.interruptInferiorAndWait(Long.parseLong(inferiorPid), interruptTimeout, rm);
						} else {
							assert false : "why don't we have the inferior's pid?"; //$NON-NLS-1$
							fGdb.interruptAndWait(interruptTimeout, rm);
						}
					} else {
						fGdb.interruptAndWait(interruptTimeout, rm);
					}
				} else {
					rm.setStatus(new Status(IStatus.ERROR, GdbPlugin.PLUGIN_ID, INVALID_STATE,
							"Context cannot be suspended.", null)); //$NON-NLS-1$
					rm.done();
				}
			}
		});
	}

	/*
	 * This is a HACK. Remove this method when GDB starts to account exited threads id in -thread-list-id command.
	 * Exited threads are reported in -thread-list-id command even after an exit event is raised by GDB
	 * Hence, this method needs a special handling in case of GDB.
	 * Raises ExitEvent when a thread really exits from the system. This is done by comparing the execution contexts list
	 * See bug 200615 for details.
	 */
	@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();
					raiseExitEvents(execDmcs);
					fOldExecutionCtxts = execDmcs;
					rm.setData(fOldExecutionCtxts);
				} else {
					rm.setStatus(
							new Status(IStatus.ERROR, GdbPlugin.PLUGIN_ID, INTERNAL_ERROR, "Invalid contexts", null)); //$NON-NLS-1$
				}
				rm.done();
			}
		});
	}

	private void raiseExitEvents(IExecutionDMContext[] ctxts) {
		if (ctxts == null || fOldExecutionCtxts == null)
			return;
		List<IExecutionDMContext> list = Arrays.asList(ctxts);
		List<IExecutionDMContext> oldThreadList = Arrays.asList(fOldExecutionCtxts);
		Iterator<IExecutionDMContext> iterator = oldThreadList.iterator();
		while (iterator.hasNext()) {
			IExecutionDMContext ctxt = iterator.next();
			if (!list.contains(ctxt)) {
				IContainerDMContext containerDmc = DMContexts.getAncestorOfType(ctxt, IContainerDMContext.class);
				MIEvent<?> e = new MIThreadExitEvent(containerDmc, ((IMIExecutionDMContext) ctxt).getThreadId());
				// Dispatch DsfMIThreadExitEvent
				getSession().dispatchEvent(e, getProperties());
			}
		}
	}

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

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

	/**
	 * @since 2.0
	 */
	@Override
	public void canStep(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) {
			// 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 {
							canResume(context, rm);
						}
					}
				});
				return;
			}
		}

		canResume(context, rm);
	}

	/** @since 3.0 */
	@Override
	public void runToLocation(IExecutionDMContext context, final String location, final boolean skipBreakpoints,
			final 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, NOT_SUPPORTED,
					"Given context: " + context + " is not an execution context.", null)); //$NON-NLS-1$ //$NON-NLS-2$
			rm.done();
			return;
		}

		if (doCanResume(dmc)) {
			IBreakpointsTargetDMContext bpDmc = DMContexts.getAncestorOfType(context,
					IBreakpointsTargetDMContext.class);
			getConnection().queueCommand(
					fCommandFactory.createMIBreakInsert(bpDmc, true, false, null, 0, location, dmc.getThreadId()),
					new DataRequestMonitor<MIBreakInsertInfo>(getExecutor(), rm) {
						@Override
						public void handleSuccess() {
							// We must set are RunToLineActiveOperation *before* we do the resume
							// or else we may get the stopped event, before we have set this variable.
							String bpId = getData().getMIBreakpoints()[0].getNumber();
							String addr = getData().getMIBreakpoints()[0].getAddress();
							fRunToLineActiveOperation = new RunToLineActiveOperation(dmc, bpId, location, addr,
									skipBreakpoints);

							resume(dmc, new RequestMonitor(getExecutor(), rm) {
								@Override
								public void handleFailure() {
									IBreakpointsTargetDMContext bpDmc = DMContexts.getAncestorOfType(
											fRunToLineActiveOperation.getThreadContext(),
											IBreakpointsTargetDMContext.class);
									String bpId = fRunToLineActiveOperation.getBreakointId();

									getConnection().queueCommand(
											fCommandFactory.createMIBreakDelete(bpDmc, new String[] { bpId }),
											new DataRequestMonitor<MIInfo>(getExecutor(), null));
									fRunToLineActiveOperation = null;
									fStepInToSelectionActiveOperation = null;

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

	/**
	 * @nooverride This method is not intended to be re-implemented or extended by clients.
	 * @noreference This method is not intended to be referenced by clients.
	 *
	 * @since 2.0
	 */
	@DsfServiceEventHandler
	public void eventDispatched(MIInferiorExitEvent e) {
		if (fRunToLineActiveOperation != null) {
			IBreakpointsTargetDMContext bpDmc = DMContexts
					.getAncestorOfType(fRunToLineActiveOperation.getThreadContext(), IBreakpointsTargetDMContext.class);
			String bpId = fRunToLineActiveOperation.getBreakointId();

			getConnection().queueCommand(fCommandFactory.createMIBreakDelete(bpDmc, new String[] { bpId }),
					new DataRequestMonitor<MIInfo>(getExecutor(), null));
			fRunToLineActiveOperation = null;
			fStepInToSelectionActiveOperation = null;
		}
	}

	/** @since 2.0 */
	@Override
	@DsfServiceEventHandler
	public void eventDispatched(final MIStoppedEvent e) {
		// A disabled signal event is due to interrupting the target
		// to set a breakpoint.  This can happen during a run-to-line
		// or step-into operation, so we need to check it first.
		if (fDisableNextSignalEvent && e instanceof MISignalEvent) {
			fDisableNextSignalEvent = false;
			fSilencedSignalEvent = e;
			// We don't broadcast this stopped event
			return;
		}

		if (processRunToLineStoppedEvent(e)) {
			// If RunToLine is not completed
			return;
		}

		if (!processStepIntoSelection(e)) {
			//Step into Selection is not in progress broadcast the stop event
			super.eventDispatched(e);
		}
	}

	/* (non-Javadoc)
	 * @see org.eclipse.cdt.dsf.mi.service.MIRunControl#eventDispatched(org.eclipse.cdt.dsf.mi.service.command.events.MIRunningEvent)
	 */
	@Override
	@DsfServiceEventHandler
	public void eventDispatched(final MIRunningEvent e) {
		if (fDisableNextRunningEvent) {
			// Leave the action to the super class
			super.eventDispatched(e);
			return;
		}

		if (fRunToLineActiveOperation == null && fStepInToSelectionActiveOperation == null) {
			// No special case here, i.e. send notification
			super.eventDispatched(e);
		} else {
			// Either RuntoLine or StepIntoSelection operations are active
			if (fLatestEvent instanceof ISuspendedDMEvent) {
				// Need to send out Running event notification only once per operation, then a stop event is expected at
				// the end of it
				super.eventDispatched(e);
			}
		}

		// No event dispatched if RuntoLine or StepIntoSelection operations are active and a previous event is not a
		// Suspended event, i.e. only one Running event distributed per operation
	}

	private boolean processRunToLineStoppedEvent(final MIStoppedEvent e) {
		if (fRunToLineActiveOperation != null) {
			String bpId = ""; //$NON-NLS-1$
			if (e instanceof MIBreakpointHitEvent) {
				bpId = ((MIBreakpointHitEvent) e).getNumber();
			}

			// Here we check three different things to see if we are stopped at the right place
			// 1- The actual location in the file.  But this does not work for breakpoints that
			//    were set on non-executable lines
			// 2- The address where the breakpoint was set.  But this does not work for breakpoints
			//    that have multiple addresses (GDB returns <MULTIPLE>.)  I think that is for multi-process
			// 3- The breakpoint id that was hit.  But this does not work if another breakpoint
			//    was also set on the same line because GDB may return that breakpoint as being hit.
			//
			// So this works for the large majority of cases.  The case that won't work is when the user
			// does a runToLine to a line that is non-executable AND has another breakpoint AND
			// has multiple addresses for the breakpoint.  I'm mean, come on!
			boolean equalFileLocation = false;
			boolean equalAddrLocation = false;
			boolean equalBpId = bpId.equals(fRunToLineActiveOperation.getBreakointId());
			MIFrame frame = e.getFrame();
			if (frame != null) {
				String fileLocation = frame.getFile() + ":" + frame.getLine(); //$NON-NLS-1$
				String addrLocation = frame.getAddress();
				equalFileLocation = fileLocation.equals(fRunToLineActiveOperation.getFileLocation());
				equalAddrLocation = addrLocation.equals(fRunToLineActiveOperation.getAddrLocation());
			}

			if (equalFileLocation || equalAddrLocation || equalBpId) {
				// We stopped at the right place.  All is well.
				fRunToLineActiveOperation = null;
			} else {
				// Didn't stop at the right place yet
				if (fRunToLineActiveOperation.shouldSkipBreakpoints() && e instanceof MIBreakpointHitEvent) {
					getConnection().queueCommand(
							fCommandFactory.createMIExecContinue(fRunToLineActiveOperation.getThreadContext()),
							new DataRequestMonitor<MIInfo>(getExecutor(), null));

					// Don't send the stop event since we are resuming again.
					return true;
				} else {
					// Stopped at another breakpoint that we should not skip.
					// Or got an interrupt signal from a suspend command.
					// Or got an interrupt signal because the user set/changed a breakpoint.  This last case is tricky.
					// We could let the run-to-line continue its job, however, I'm thinking that if the user creates
					// a new breakpoint, she may want to force the program to stop, in a way to abort the run-to-line.
					// So, let's cancel the run-to-line in this case.
					//
					// Just remove our temporary one since we don't want it to hit later
					IBreakpointsTargetDMContext bpDmc = DMContexts.getAncestorOfType(
							fRunToLineActiveOperation.getThreadContext(), IBreakpointsTargetDMContext.class);

					getConnection().queueCommand(
							fCommandFactory.createMIBreakDelete(bpDmc,
									new String[] { fRunToLineActiveOperation.getBreakointId() }),
							new DataRequestMonitor<MIInfo>(getExecutor(), null));
					fRunToLineActiveOperation = null;
					fStepInToSelectionActiveOperation = null;
				}
			}
		}

		return false;
	}

	private boolean processStepIntoSelection(final MIStoppedEvent e) {
		if (fStepInToSelectionActiveOperation == null) {
			return false;
		}

		// First check if it is the right thread that stopped
		final IMIExecutionDMContext threadDmc = DMContexts.getAncestorOfType(e.getDMContext(),
				IMIExecutionDMContext.class);
		if (fStepInToSelectionActiveOperation.getThreadContext().equals(threadDmc)) {
			final MIFrame frame = e.getFrame();

			assert (fRunToLineActiveOperation == null);

			if (fStepInToSelectionActiveOperation.getRunToLineFrame() == null) {
				assert (fStepInToSelectionActiveOperation.getLine() == frame.getLine());
				// Shall now be at the runToline location
				fStepInToSelectionActiveOperation.setRunToLineFrame(frame);
			}

			// Step - Not at the right place just yet
			// Initiate an async call chain parent
			getStackDepth(threadDmc, new DataRequestMonitor<Integer>(getExecutor(), null) {
				private int originalStackDepth = fStepInToSelectionActiveOperation.getOriginalStackDepth();

				@Override
				protected void handleSuccess() {
					int frameDepth = getStackDepth();

					if (frameDepth > originalStackDepth) {
						//shall be true as this is using stepinto step type vs instruction stepinto
						assert (frameDepth == originalStackDepth + 1);

						// Check for a match
						if (StepIntoSelectionUtils.sameSignature(frame, fStepInToSelectionActiveOperation)) {
							// Hit !!
							stopStepIntoSelection(e);
							return;
						}

						// Located deeper in the stack, Shall continue step / search
						// Step return
						continueStepping(e, StepType.STEP_RETURN);
					} else if (frameDepth == originalStackDepth) {
						// Continue step / search as long as
						// this is the starting base line for the search
						String currentLocation = frame.getFile() + ":" + frame.getLine(); //$NON-NLS-1$
						String searchLineLocation = fStepInToSelectionActiveOperation.getFileLocation();
						if (currentLocation.equals(searchLineLocation)) {
							continueStepping(e, StepType.STEP_INTO);
						} else {
							// We have moved to a line
							// different from the base
							// search line i.e. missed the
							// target function !!
							StepIntoSelectionUtils.missedSelectedTarget(fStepInToSelectionActiveOperation);
							stopStepIntoSelection(e);
						}
					} else {
						// missed the target point
						StepIntoSelectionUtils.missedSelectedTarget(fStepInToSelectionActiveOperation);
					}
				}

				@Override
				protected void handleFailure() {
					// log error
					if (getStatus() != null) {
						GdbPlugin.getDefault().getLog().log(getStatus());
					}

					stopStepIntoSelection(e);
				}

				private int getStackDepth() {
					Integer stackDepth = null;
					if (isSuccess() && getData() != null) {
						stackDepth = getData();
						// This is the base frame, the original stack depth shall be updated
						if (frame == fStepInToSelectionActiveOperation.getRunToLineFrame()) {
							fStepInToSelectionActiveOperation.setOriginalStackDepth(stackDepth);
							originalStackDepth = stackDepth;
						}
					}

					if (stackDepth == null) {
						// Unsuccessful resolution of stack depth, default to same stack depth to detect a change of line within the original frame
						return fStepInToSelectionActiveOperation.getOriginalStackDepth();
					}

					return stackDepth.intValue();
				}
			});

			//Processing step into selection
			return true;
		}

		//All threads stopped, however outside the scope of the step into selection context
		//We need to abort the step into selection and broadcast the stop
		fStepInToSelectionActiveOperation = null;
		return false;
	}

	private void stopStepIntoSelection(final MIStoppedEvent e) {
		fStepInToSelectionActiveOperation = null;
		// Need to broadcast the stop
		super.eventDispatched(e);
	}

	/**
	 * @since 4.2
	 */
	protected int getInterruptTimeout() {
		return IGDBBackend.INTERRUPT_TIMEOUT_DEFAULT;
	}

	private void continueStepping(final MIStoppedEvent event, StepType steptype) {
		step(fStepInToSelectionActiveOperation.getThreadContext(), steptype, false,
				new RequestMonitor(getExecutor(), null) {
					@Override
					protected void handleFailure() {
						// log error
						if (getStatus() != null) {
							GdbPlugin.getDefault().getLog().log(getStatus());
						}

						stopStepIntoSelection(event);
					}
				});
	}

	// ------------------------------------------------------------------------
	// Step into Selection
	// ------------------------------------------------------------------------
	private void stepIntoSelection(final IExecutionDMContext context, final int baseLine, final String baseLineLocation,
			final boolean skipBreakpoints, final IFunctionDeclaration targetFunction, final 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 MI execution context.", null)); //$NON-NLS-1$ //$NON-NLS-2$
			rm.done();
			return;
		}

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

		if (fLatestEvent == null || !(fLatestEvent instanceof SuspendedEvent)) {
			rm.setStatus(new Status(IStatus.ERROR, GdbPlugin.PLUGIN_ID, INVALID_STATE,
					"Given context: " + context + " invalid suspended event.", null)); //$NON-NLS-1$ //$NON-NLS-2$
			rm.done();
			return;
		}

		SuspendedEvent suspendedEvent = (SuspendedEvent) fLatestEvent;
		final MIFrame currentFrame = suspendedEvent.getMIEvent().getFrame();
		if (currentFrame == null) {
			rm.setStatus(new Status(IStatus.ERROR, GdbPlugin.PLUGIN_ID, INVALID_STATE,
					"Given event: " + suspendedEvent + " with invalid frame.", null)); //$NON-NLS-1$ //$NON-NLS-2$
			rm.done();
			return;
		}

		getStackDepth(dmc, new DataRequestMonitor<Integer>(getExecutor(), rm) {
			@Override
			public void handleSuccess() {
				if (getData() != null) {
					final int framesSize = getData().intValue();

					// make sure the operation is removed upon
					// failure detection
					final RequestMonitor rms = new RequestMonitor(getExecutor(), rm) {
						@Override
						protected void handleFailure() {
							fStepInToSelectionActiveOperation = null;
							super.handleFailure();
						}
					};

					if ((currentFrame.getFile() + ":" + currentFrame.getLine()).endsWith(baseLineLocation)) { //$NON-NLS-1$
						// Save the step into selection information
						fStepInToSelectionActiveOperation = new StepIntoSelectionActiveOperation(dmc, baseLine,
								targetFunction, framesSize, currentFrame);
						// Ready to step into a function selected
						// within a current line
						step(dmc, StepType.STEP_INTO, rms);
					} else {
						// Save the step into selection information
						fStepInToSelectionActiveOperation = new StepIntoSelectionActiveOperation(dmc, baseLine,
								targetFunction, framesSize, null);
						// Pointing to a line different than the current line
						// Needs to RunToLine before stepping to the selection
						runToLocation(dmc, baseLineLocation, skipBreakpoints, rms);
					}
				} else {
					rm.done();
				}
			}
		});
	}

	/**
	 * @since 4.2
	 */
	@Override
	public void canStepIntoSelection(IExecutionDMContext context, String sourceFile, int lineNumber,
			IFunctionDeclaration selectedFunction, DataRequestMonitor<Boolean> rm) {
		canStep(context, StepType.STEP_INTO, rm);
	}

	/**
	 * @since 4.2
	 */
	@Override
	public void stepIntoSelection(final IExecutionDMContext context, String sourceFile, final int lineNumber,
			final boolean skipBreakpoints, final IFunctionDeclaration selectedFunction, final RequestMonitor rm) {
		determineDebuggerPath(context, sourceFile, new ImmediateDataRequestMonitor<String>(rm) {
			@Override
			protected void handleSuccess() {
				stepIntoSelection(context, lineNumber, getData() + ":" + Integer.toString(lineNumber), skipBreakpoints, //$NON-NLS-1$
						selectedFunction, rm);
			}
		});
	}

	/**
	 * Help method used when the stopped event has not been broadcasted e.g. in the middle of step into selection
	 *
	 * @param dmc
	 * @param rm
	 */
	private void getStackDepth(final IMIExecutionDMContext dmc, final DataRequestMonitor<Integer> rm) {
		if (dmc != null) {
			fConnection.queueCommand(fCommandFactory.createMIStackInfoDepth(dmc),
					new DataRequestMonitor<MIStackInfoDepthInfo>(getExecutor(), rm) {
						@Override
						protected void handleSuccess() {
							rm.setData(getData().getDepth());
							rm.done();
						}
					});
		} else {
			rm.setStatus(new Status(IStatus.ERROR, GdbPlugin.PLUGIN_ID, INVALID_HANDLE, "Invalid context", null)); //$NON-NLS-1$
			rm.done();
		}
	}

}