### Eclipse Workspace Patch 1.0
#P org.eclipse.mat.api
Index: src/org/eclipse/mat/inspections/ReachableSetQuery.java
===================================================================
--- src/org/eclipse/mat/inspections/ReachableSetQuery.java	(revision 0)
+++ src/org/eclipse/mat/inspections/ReachableSetQuery.java	(revision 0)
@@ -0,0 +1,51 @@
+/*******************************************************************************
+ * Copyright (c) 2010 SAP AG.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *
+ * Contributors:
+ *    SAP AG - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.mat.inspections;
+
+import org.eclipse.mat.query.IQuery;
+import org.eclipse.mat.query.IResult;
+import org.eclipse.mat.query.annotations.Argument;
+import org.eclipse.mat.query.annotations.CommandName;
+import org.eclipse.mat.snapshot.Histogram;
+import org.eclipse.mat.snapshot.ISnapshot;
+import org.eclipse.mat.snapshot.query.IHeapObjectArgument;
+import org.eclipse.mat.util.IProgressListener;
+import org.eclipse.mat.util.MessageUtil;
+
+@CommandName("show_reachable_set")
+public class ReachableSetQuery implements IQuery
+{
+	@Argument
+	public ISnapshot snapshot;
+
+	@Argument(flag = "none")
+	public IHeapObjectArgument objects;
+
+	@Argument(isMandatory = false, flag = "f")
+	public String[] fieldNames;
+
+	public IResult execute(IProgressListener listener) throws Exception
+	{
+		int[] reachableSet;
+
+		reachableSet = snapshot.getReachableSet(objects.getIds(listener), listener);
+
+		if (listener.isCanceled()) throw new IProgressListener.OperationCanceledException();
+
+		Histogram histogram = snapshot.getHistogram(reachableSet, listener);
+
+		if (listener.isCanceled()) throw new IProgressListener.OperationCanceledException();
+
+		histogram.setLabel(MessageUtil.format("Reachable Set", objects.getLabel()));
+		return histogram;
+	}
+
+}
Index: src/org/eclipse/mat/snapshot/ISnapshot.java
===================================================================
--- src/org/eclipse/mat/snapshot/ISnapshot.java	(revision 654)
+++ src/org/eclipse/mat/snapshot/ISnapshot.java	(working copy)
@@ -324,6 +324,8 @@
 
     public int[] getRetainedSet(int[] objectIds, ExcludedReferencesDescriptor[] excludedReferences,
                     IProgressListener progressMonitor) throws SnapshotException;
+    
+    public int[] getReachableSet(int[] objectIds, IProgressListener progressListener) throws SnapshotException;
 
     /**
      * Calculate the minimum retained set of objects for the given objects
Index: plugin.xml
===================================================================
--- plugin.xml	(revision 654)
+++ plugin.xml	(working copy)
@@ -20,6 +20,7 @@
 		<query impl="org.eclipse.mat.inspections.HistogramQuery"/>
 		<query impl="org.eclipse.mat.inspections.RetainedSetQuery"/>
 		<query impl="org.eclipse.mat.inspections.CustomizedRetainedSetQuery"/>
+		<query impl="org.eclipse.mat.inspections.ReachableSetQuery"/>
 		<query impl="org.eclipse.mat.inspections.DuplicatedClassesQuery"/>
 		<query impl="org.eclipse.mat.inspections.GroupByValueQuery"/>
 		<query impl="org.eclipse.mat.inspections.OQLQuery"/>
#P org.eclipse.mat.parser
Index: src/org/eclipse/mat/parser/internal/SnapshotImpl.java
===================================================================
--- src/org/eclipse/mat/parser/internal/SnapshotImpl.java	(revision 637)
+++ src/org/eclipse/mat/parser/internal/SnapshotImpl.java	(working copy)
@@ -705,7 +705,7 @@
         return retained.toArray();
 
     }
-
+    
     public int[] getRetainedSet(int[] objectIds, IProgressListener progressMonitor) throws SnapshotException
     {
         int availableProcessors = Runtime.getRuntime().availableProcessors();
@@ -802,6 +802,72 @@
         }
         return retainedSet.toArray();
     }
+    
+    public int[] getReachableSet(int[] objectIds, IProgressListener progressListener) throws SnapshotException
+    {
+        /* for empty initial set - return immediately an empty reachable set */
+        if (objectIds.length == 0) { return new int[0]; }
+
+        int numberOfObjects = snapshotInfo.getNumberOfObjects();
+
+        if (progressListener == null)
+        	progressListener = new VoidProgressListener();
+
+        /* a 'bit field' to mark all reached objects */
+        boolean[] reachable = new boolean[numberOfObjects];
+
+        /*
+         * The dfs() will start from the GC roots, follow the outbound
+         * references, and mark all unmarked objects. The reachable set will
+         * contain the marked objects
+         */
+        ObjectMarker marker = new ObjectMarker(roots.getAllKeys(), reachable, indexManager.outbound(), progressListener);
+        try
+        {
+            int availableProcessors = Runtime.getRuntime().availableProcessors();
+            if (availableProcessors > 1)
+            {
+                marker.markMultiThreaded(availableProcessors);
+                /*
+                 * build the result in an IntArray - the exact number of marked is not
+                 * known
+                 */
+                ArrayIntBig retained = new ArrayIntBig();
+
+                /* Put each unmarked object into the retained set */
+                for (int i = 0; i < numberOfObjects; i++)
+                {
+                    if (reachable[i])
+                    {
+                        retained.add(i);
+                    }
+                }
+                return retained.toArray();
+            }
+            else
+            {
+                int numObjectsReached = marker.markSingleThreaded();
+                int[] reachableSet = new int[numObjectsReached];
+                int j = 0;
+                for (int i = 0; i < reachable.length; i++)
+				{
+					if (reachable[i])
+						reachableSet[j++] = i;
+				}
+                return reachableSet;
+            }
+        }
+        catch (OperationCanceledException e)
+        {
+            // $JL-EXC$
+            return null;
+        }
+        catch (InterruptedException e)
+        {
+            // $JL-EXC$
+            return null;
+        }
+    }
 
     public long getMinRetainedSize(int[] objectIds, IProgressListener progressMonitor)
                     throws UnsupportedOperationException, SnapshotException