### Eclipse Workspace Patch 1.0
#P org.eclipse.equinox.p2.garbagecollector
Index: META-INF/MANIFEST.MF
===================================================================
RCS file: /cvsroot/rt/org.eclipse.equinox/p2/bundles/org.eclipse.equinox.p2.garbagecollector/META-INF/MANIFEST.MF,v
retrieving revision 1.11
diff -u -r1.11 MANIFEST.MF
--- META-INF/MANIFEST.MF	17 Jul 2008 19:39:39 -0000	1.11
+++ META-INF/MANIFEST.MF	16 Apr 2009 19:50:49 -0000
@@ -12,7 +12,9 @@
  org.eclipse.equinox.internal.provisional.p2.core,
  org.eclipse.equinox.internal.provisional.p2.core.eventbus,
  org.eclipse.equinox.internal.provisional.p2.metadata,
+ org.eclipse.equinox.internal.provisional.p2.metadata.query,
  org.eclipse.equinox.internal.provisional.p2.metadata.repository,
+ org.eclipse.equinox.internal.provisional.p2.query,
  org.eclipse.osgi.util;version="1.1.0",
  org.osgi.framework;version="1.4.0",
  org.osgi.service.prefs;version="1.1.0",
Index: src/org/eclipse/equinox/internal/p2/garbagecollector/GCActivator.java
===================================================================
RCS file: /cvsroot/rt/org.eclipse.equinox/p2/bundles/org.eclipse.equinox.p2.garbagecollector/src/org/eclipse/equinox/internal/p2/garbagecollector/GCActivator.java,v
retrieving revision 1.8
diff -u -r1.8 GCActivator.java
--- src/org/eclipse/equinox/internal/p2/garbagecollector/GCActivator.java	10 Mar 2009 19:03:35 -0000	1.8
+++ src/org/eclipse/equinox/internal/p2/garbagecollector/GCActivator.java	16 Apr 2009 19:50:49 -0000
@@ -18,6 +18,8 @@
 import org.eclipse.equinox.internal.provisional.p2.core.eventbus.IProvisioningEventBus;
 import org.eclipse.equinox.internal.provisional.p2.core.eventbus.SynchronousProvisioningListener;
 import org.eclipse.equinox.internal.provisional.p2.engine.*;
+import org.eclipse.equinox.internal.provisional.p2.metadata.query.InstallableUnitQuery;
+import org.eclipse.equinox.internal.provisional.p2.query.Collector;
 import org.eclipse.osgi.service.debug.DebugOptions;
 import org.osgi.framework.*;
 import org.osgi.service.prefs.Preferences;
@@ -58,25 +60,37 @@
 			return;
 		}
 		eventBus.addListener(busListener = new SynchronousProvisioningListener() {
-			//The GC is triggered when an uninstall event occurred during a "transaction" and the transaction is committed.   
-			private boolean uninstallEventOccurred = false;
+
+			private Map activeProfiles = Collections.synchronizedMap(new HashMap());
 
 			public void notify(EventObject o) {
-				if (o instanceof InstallableUnitEvent) {
-					InstallableUnitEvent event = (InstallableUnitEvent) o;
-					if (event.isUninstall() && event.isPost()) {
-						uninstallEventOccurred = true;
-					}
-				} else if (o instanceof CommitOperationEvent) {
-					if (uninstallEventOccurred == true) {
-						CommitOperationEvent event = (CommitOperationEvent) o;
-						if (getBooleanPreference(GC_ENABLED, true)) {
-							new GarbageCollector().runGC(event.getProfile());
-						}
-						uninstallEventOccurred = false;
-					}
-				} else if (o instanceof RollbackOperationEvent) {
-					uninstallEventOccurred = false;
+				// Return if the event isn't a TransactionEvent
+				if (!(o instanceof TransactionEvent))
+					return;
+				// Return if garbage collection is disabled
+				if (!getBooleanPreference(GC_ENABLED, true))
+					return;
+
+				TransactionEvent event = (TransactionEvent) o;
+				IProfile profile = event.getProfile();
+
+				if (profile == null)
+					return;
+
+				if (event instanceof RollbackOperationEvent)
+					// Transaction rolled back, profile data can be removed
+					activeProfiles.remove(profile.getProfileId());
+				else if (event instanceof BeginOperationEvent) {
+					// Store a collection of IUs present in the profile at the start of the Transaction 
+					Collection profileIUs = profile.query(InstallableUnitQuery.ANY, new Collector(), null).toCollection();
+					activeProfiles.put(profile.getProfileId(), profileIUs);
+				} else if (event instanceof CommitOperationEvent) {
+					// Retrieve collection of IUs present in the profile at the end of the Transaction 
+					Collection profileIUs = profile.query(InstallableUnitQuery.ANY, new Collector(), null).toCollection();
+					Collection previousIUs = (Collection) activeProfiles.remove(profile.getProfileId());
+					// Run GC if IUs were present in the profile before, but are now missing from the profile
+					if (previousIUs != null && !profileIUs.containsAll(previousIUs))
+						new GarbageCollector().runGC(event.getProfile());
 				}
 			}
 		});