[576969] Revisions in the CDORevisionCache should be interned

https://bugs.eclipse.org/bugs/show_bug.cgi?id=576969

15 files changed, 207 insertions, 110 deletions

diff --git a/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/common/revision/CDORevision.java b/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/common/revision/CDORevision.java
index 11adcfa0f1..214cc9386c 100644
--- a/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/common/revision/CDORevision.java
+++ b/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/common/revision/CDORevision.java
@@ -94,11 +94,6 @@ public interface CDORevision extends CDORevisionKey, CDORevisable
   public boolean isValid(CDOBranchPoint branchPoint);
 
   /**
-   * @since 4.15
-   */
-  public boolean isValid(CDOBranchPoint branchPoint, boolean considerBases);
-
-  /**
    * @since 2.0
    */
   public boolean isResourceNode();
diff --git a/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/common/revision/CDORevisionCache.java b/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/common/revision/CDORevisionCache.java
index e5001aaf6b..030493ef28 100644
--- a/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/common/revision/CDORevisionCache.java
+++ b/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/common/revision/CDORevisionCache.java
@@ -32,7 +32,7 @@ import java.util.function.Consumer;
  * @noextend This interface is not intended to be extended by clients.
  * @noimplement This interface is not intended to be implemented by clients.
  */
-public interface CDORevisionCache extends CDORevisionCacheAdder, INotifier
+public interface CDORevisionCache extends INotifier
 {
   /**
    * @since 3.0
diff --git a/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/common/revision/CDORevisionCacheAdder.java b/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/common/revision/CDORevisionCacheAdder.java
index 95698dfa46..e84b55de14 100644
--- a/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/common/revision/CDORevisionCacheAdder.java
+++ b/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/common/revision/CDORevisionCacheAdder.java
@@ -15,7 +15,9 @@ package org.eclipse.emf.cdo.common.revision;
  *
  * @author Eike Stepper
  * @since 4.0
+ * @deprecated as of 4.15 use {@link CDORevisionInterner}.
  */
+@Deprecated
 public interface CDORevisionCacheAdder
 {
   /**
diff --git a/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/common/revision/CDORevisionInterner.java b/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/common/revision/CDORevisionInterner.java
new file mode 100644
index 0000000000..26d67eb5c7
--- /dev/null
+++ b/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/common/revision/CDORevisionInterner.java
@@ -0,0 +1,28 @@
+/*
+ * Copyright (c) 2021 Eike Stepper (Loehne, Germany) and others.
+ * 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:
+ *    Eike Stepper - initial API and implementation
+ */
+package org.eclipse.emf.cdo.common.revision;
+
+/**
+ * @author Eike Stepper
+ * @since 4.15
+ */
+public interface CDORevisionInterner
+{
+  /**
+   * Interns the given revision and returns either the given revision or
+   * a revision with the same {@link CDORevisionKey key} that was interned previously.
+   * <p>
+   * The returned revision is only different from the passed revision if this interner
+   * contains a previously cached, different revision instance with an equal
+   * {@link CDORevisionKey revision key}.
+   */
+  public CDORevision internRevision(CDORevision revision);
+}
diff --git a/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/internal/common/revision/AbstractCDORevisionCache.java b/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/internal/common/revision/AbstractCDORevisionCache.java
index c60b0c084f..14ef402913 100644
--- a/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/internal/common/revision/AbstractCDORevisionCache.java
+++ b/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/internal/common/revision/AbstractCDORevisionCache.java
@@ -122,21 +122,6 @@ public abstract class AbstractCDORevisionCache extends Lifecycle implements Inte
   }
 
   @Override
-  public final void addRevision(CDORevision revision)
-  {
-    referenceQueue.register((InternalCDORevision)revision);
-    doAddRevision(revision);
-
-    IListener[] listeners = getListeners();
-    if (listeners != null)
-    {
-      fireEvent(new CacheAdditionEvent(this, revision));
-    }
-  }
-
-  protected abstract void doAddRevision(CDORevision revision);
-
-  @Override
   public final CDORevision removeRevision(CDOID id, CDOBranchVersion branchVersion)
   {
     referenceQueue.clean();
diff --git a/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/internal/common/revision/CDORevisionCacheAuditing.java b/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/internal/common/revision/CDORevisionCacheAuditing.java
index 854089eec7..423304a896 100644
--- a/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/internal/common/revision/CDORevisionCacheAuditing.java
+++ b/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/internal/common/revision/CDORevisionCacheAuditing.java
@@ -23,6 +23,7 @@ import org.eclipse.emf.cdo.spi.common.revision.InternalCDORevision;
 import org.eclipse.emf.cdo.spi.common.revision.InternalCDORevisionCache;
 
 import org.eclipse.net4j.util.CheckUtil;
+import org.eclipse.net4j.util.event.IListener;
 import org.eclipse.net4j.util.om.trace.ContextTracer;
 
 import org.eclipse.emf.ecore.EClass;
@@ -36,6 +37,7 @@ import java.util.List;
 import java.util.ListIterator;
 import java.util.Map;
 import java.util.function.Consumer;
+import java.util.function.Supplier;
 
 /**
  * @author Eike Stepper
@@ -183,7 +185,7 @@ public class CDORevisionCacheAuditing extends AbstractCDORevisionCache
   }
 
   @Override
-  protected void doAddRevision(CDORevision revision)
+  public CDORevision internRevision(CDORevision revision)
   {
     CheckUtil.checkArg(revision, "revision");
 
@@ -193,18 +195,41 @@ public class CDORevisionCacheAuditing extends AbstractCDORevisionCache
     CDOID id = revision.getID();
     Object key = createKey(id, branch);
 
-    synchronized (revisionLists)
+    IListener[] listeners = getListeners();
+    CacheAdditionEvent event = null;
+
+    try
     {
-      RevisionList list = revisionLists.get(key);
-      if (list == null)
+      synchronized (revisionLists)
       {
-        list = new RevisionList();
-        revisionLists.put(key, list);
+        RevisionList list = revisionLists.get(key);
+        if (list == null)
+        {
+          list = new RevisionList();
+          revisionLists.put(key, list);
+        }
+
+        CDORevision cachedRevision = list.addRevision(revision, () -> createReference(revision));
+        if (cachedRevision != revision)
+        {
+          return cachedRevision;
+        }
+
+        typeRefIncrease(id, revision.getEClass());
       }
 
-      if (list.addRevision((InternalCDORevision)revision, createReference(revision)))
+      if (listeners.length != 0)
       {
-        typeRefIncrease(id, revision.getEClass());
+        event = new CacheAdditionEvent(this, revision);
+      }
+
+      return revision;
+    }
+    finally
+    {
+      if (event != null)
+      {
+        fireEvent(event, listeners);
       }
     }
   }
@@ -293,7 +318,7 @@ public class CDORevisionCacheAuditing extends AbstractCDORevisionCache
     {
     }
 
-    public synchronized InternalCDORevision getRevision(long timeStamp)
+    public InternalCDORevision getRevision(long timeStamp)
     {
       if (timeStamp == CDORevision.UNSPECIFIED_DATE)
       {
@@ -344,7 +369,7 @@ public class CDORevisionCacheAuditing extends AbstractCDORevisionCache
       return null;
     }
 
-    public synchronized InternalCDORevision getRevisionByVersion(int version)
+    public InternalCDORevision getRevisionByVersion(int version)
     {
       for (Iterator<Reference<InternalCDORevision>> it = iterator(); it.hasNext();)
       {
@@ -371,7 +396,7 @@ public class CDORevisionCacheAuditing extends AbstractCDORevisionCache
       return null;
     }
 
-    public synchronized boolean addRevision(InternalCDORevision revision, Reference<InternalCDORevision> reference)
+    public CDORevision addRevision(CDORevision revision, Supplier<Reference<InternalCDORevision>> referenceCreator)
     {
       int version = revision.getVersion();
       for (ListIterator<Reference<InternalCDORevision>> it = listIterator(); it.hasNext();)
@@ -384,14 +409,14 @@ public class CDORevisionCacheAuditing extends AbstractCDORevisionCache
           int v = key.getVersion();
           if (v == version)
           {
-            return false;
+            return foundRevision;
           }
 
           if (v < version)
           {
             it.previous();
-            it.add(reference);
-            return true;
+            it.add(referenceCreator.get());
+            return revision;
           }
         }
         else
@@ -400,11 +425,11 @@ public class CDORevisionCacheAuditing extends AbstractCDORevisionCache
         }
       }
 
-      addLast(reference);
-      return true;
+      addLast(referenceCreator.get());
+      return revision;
     }
 
-    public synchronized void removeRevision(int version)
+    public void removeRevision(int version)
     {
       for (Iterator<Reference<InternalCDORevision>> it = iterator(); it.hasNext();)
       {
diff --git a/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/internal/common/revision/CDORevisionCacheNonAuditing.java b/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/internal/common/revision/CDORevisionCacheNonAuditing.java
index c598346bda..2dc2a99723 100644
--- a/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/internal/common/revision/CDORevisionCacheNonAuditing.java
+++ b/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/internal/common/revision/CDORevisionCacheNonAuditing.java
@@ -22,6 +22,7 @@ import org.eclipse.emf.cdo.spi.common.revision.InternalCDORevision;
 import org.eclipse.emf.cdo.spi.common.revision.InternalCDORevisionCache;
 
 import org.eclipse.net4j.util.CheckUtil;
+import org.eclipse.net4j.util.event.IListener;
 
 import org.eclipse.emf.ecore.EClass;
 
@@ -194,7 +195,7 @@ public class CDORevisionCacheNonAuditing extends AbstractCDORevisionCache
   }
 
   @Override
-  protected void doAddRevision(CDORevision revision)
+  public CDORevision internRevision(CDORevision revision)
   {
     CheckUtil.checkArg(revision, "revision");
     checkBranch(revision.getBranch());
@@ -202,25 +203,56 @@ public class CDORevisionCacheNonAuditing extends AbstractCDORevisionCache
     if (!revision.isHistorical())
     {
       CDOID id = revision.getID();
-      Reference<InternalCDORevision> reference = createReference(revision);
+      CDORevision passedRevision = revision;
+
+      IListener[] listeners = getListeners();
+      CacheAdditionEvent[] event = { null };
 
       synchronized (revisions)
       {
-        Reference<InternalCDORevision> oldReference = revisions.put(id, reference);
-        if (oldReference != null)
+        try
         {
-          InternalCDORevision oldRevision = oldReference.get();
-          if (oldRevision != null)
-          {
-            if (oldRevision.getVersion() > revision.getVersion())
+          revisions.compute(id, (k, cachedReference) -> {
+            if (cachedReference != null)
             {
-              // Put the old revision back because it's newer.
-              revisions.put(id, oldReference);
+              InternalCDORevision cachedRevision = cachedReference.get();
+              if (cachedRevision != null)
+              {
+                if (cachedRevision.getVersion() > passedRevision.getVersion())
+                {
+                  // Keep the cachedRevision in the cache because it's basically newer than the passedRevision,
+                  // but don't change the result of internRevision().
+                  throw new KeepCachedRevision(passedRevision);
+                }
+
+                if (cachedRevision.equals(passedRevision))
+                {
+                  // Keep the cachedRevision in the cache because it's basically equal to the passedRevision,
+                  // and change the result of internRevision() to the already cachedRevision.
+                  throw new KeepCachedRevision(cachedRevision);
+                }
+              }
             }
-          }
+
+            // No revision is already cached, so cache and return the passedRevision.
+            if (listeners.length != 0)
+            {
+              event[0] = new CacheAdditionEvent(this, passedRevision);
+            }
+
+            return createReference(passedRevision);
+          });
+        }
+        catch (KeepCachedRevision ex)
+        {
+          revision = ex.returnValue;
         }
       }
+
+      fireEvent(event[0]);
     }
+
+    return revision;
   }
 
   @Override
@@ -259,4 +291,19 @@ public class CDORevisionCacheNonAuditing extends AbstractCDORevisionCache
       revisions.clear();
     }
   }
+
+  /**
+   * @author Eike Stepper
+   */
+  private static final class KeepCachedRevision extends RuntimeException
+  {
+    private static final long serialVersionUID = 1L;
+
+    public final CDORevision returnValue;
+
+    public KeepCachedRevision(CDORevision returnValue)
+    {
+      this.returnValue = returnValue;
+    }
+  }
 }
diff --git a/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/internal/common/revision/CDORevisionManagerImpl.java b/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/internal/common/revision/CDORevisionManagerImpl.java
index e44d27e1df..7911df07a6 100644
--- a/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/internal/common/revision/CDORevisionManagerImpl.java
+++ b/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/internal/common/revision/CDORevisionManagerImpl.java
@@ -26,7 +26,6 @@ import org.eclipse.emf.cdo.common.revision.CDORevisionManager;
 import org.eclipse.emf.cdo.common.revision.CDORevisionUtil;
 import org.eclipse.emf.cdo.common.revision.CDORevisionsLoadedEvent;
 import org.eclipse.emf.cdo.internal.common.bundle.OM;
-import org.eclipse.emf.cdo.spi.common.branch.CDOBranchUtil;
 import org.eclipse.emf.cdo.spi.common.revision.DetachedCDORevision;
 import org.eclipse.emf.cdo.spi.common.revision.InternalCDORevision;
 import org.eclipse.emf.cdo.spi.common.revision.InternalCDORevisionCache;
@@ -273,7 +272,7 @@ public class CDORevisionManagerImpl extends Lifecycle implements InternalCDORevi
           }
 
           revision = revisionLoader.loadRevisionByVersion(id, branchVersion, referenceChunk);
-          addRevision(revision);
+          revision = (InternalCDORevision)internRevision(revision);
         }
       }
 
@@ -517,7 +516,7 @@ public class CDORevisionManagerImpl extends Lifecycle implements InternalCDORevi
   }
 
   @Override
-  public void addRevision(CDORevision revision)
+  public CDORevision internRevision(CDORevision revision)
   {
     if (revision != null)
     {
@@ -525,18 +524,6 @@ public class CDORevisionManagerImpl extends Lifecycle implements InternalCDORevi
 
       try
       {
-        if (revision instanceof PointerCDORevision)
-        {
-          PointerCDORevision pointer = (PointerCDORevision)revision;
-          CDOBranchVersion target = pointer.getTarget();
-          if (target instanceof InternalCDORevision)
-          {
-            // Replace the target CDORevision by a proper CDOBranchVersion.
-            revision = new PointerCDORevision(pointer.getEClass(), pointer.getID(), pointer.getBranch(), pointer.getRevised(),
-                CDOBranchUtil.copyBranchVersion(target));
-          }
-        }
-
         int oldVersion = revision.getVersion() - 1;
         if (oldVersion >= CDORevision.UNSPECIFIED_VERSION)
         {
@@ -564,13 +551,22 @@ public class CDORevisionManagerImpl extends Lifecycle implements InternalCDORevi
           }
         }
 
-        cache.addRevision(revision);
+        revision = cache.internRevision(revision);
       }
       finally
       {
         releaseAtomicRequestLock(loadAndAddLock);
       }
     }
+
+    return revision;
+  }
+
+  @Deprecated
+  @Override
+  public void addRevision(CDORevision revision)
+  {
+    internRevision(revision);
   }
 
   @Override
diff --git a/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/internal/common/revision/NOOPRevisionCache.java b/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/internal/common/revision/NOOPRevisionCache.java
index 7f30198a6e..a8ece823e1 100644
--- a/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/internal/common/revision/NOOPRevisionCache.java
+++ b/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/internal/common/revision/NOOPRevisionCache.java
@@ -87,9 +87,9 @@ public class NOOPRevisionCache extends Lifecycle implements InternalCDORevisionC
   }
 
   @Override
-  public void addRevision(CDORevision revision)
+  public CDORevision internRevision(CDORevision revision)
   {
-    // Do nothing
+    return revision;
   }
 
   @Override
diff --git a/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/spi/common/revision/AbstractCDORevision.java b/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/spi/common/revision/AbstractCDORevision.java
index e7b85508a6..11b011fbca 100644
--- a/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/spi/common/revision/AbstractCDORevision.java
+++ b/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/spi/common/revision/AbstractCDORevision.java
@@ -168,30 +168,6 @@ public abstract class AbstractCDORevision implements InternalCDORevision
   }
 
   /**
-   * @since 4.15
-   */
-  @Override
-  public boolean isValid(CDOBranchPoint branchPoint, boolean considerBases)
-  {
-    if (considerBases)
-    {
-      do
-      {
-        if (isValid(branchPoint))
-        {
-          return true;
-        }
-
-        branchPoint = branchPoint.getBranch().getBase();
-      } while (branchPoint.getBranch() != null);
-
-      return false;
-    }
-
-    return isValid(branchPoint);
-  }
-
-  /**
    * @since 4.1
    */
   @Override
diff --git a/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/spi/common/revision/DelegatingCDORevision.java b/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/spi/common/revision/DelegatingCDORevision.java
index 3158063aec..a273a3004e 100644
--- a/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/spi/common/revision/DelegatingCDORevision.java
+++ b/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/spi/common/revision/DelegatingCDORevision.java
@@ -185,15 +185,6 @@ public abstract class DelegatingCDORevision implements InternalCDORevision
   }
 
   /**
-   * @since 4.15
-   */
-  @Override
-  public boolean isValid(CDOBranchPoint branchPoint, boolean considerBases)
-  {
-    return getDelegate().isValid(branchPoint, considerBases);
-  }
-
-  /**
    * @since 4.0
    */
   @Override
@@ -612,7 +603,7 @@ public abstract class DelegatingCDORevision implements InternalCDORevision
    * @author Eike Stepper
    */
   @SuppressWarnings("unused")
-  private static final class InternalCompletenessTest extends DelegatingCDORevision
+  private static final class InternalCompletenessChecker extends DelegatingCDORevision
   {
     @Override
     public InternalCDORevision getDelegate()
diff --git a/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/spi/common/revision/DelegatingCDORevisionManager.java b/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/spi/common/revision/DelegatingCDORevisionManager.java
index 6e27daf078..afcb24dc62 100644
--- a/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/spi/common/revision/DelegatingCDORevisionManager.java
+++ b/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/spi/common/revision/DelegatingCDORevisionManager.java
@@ -11,12 +11,15 @@
 package org.eclipse.emf.cdo.spi.common.revision;
 
 import org.eclipse.emf.cdo.common.branch.CDOBranch;
+import org.eclipse.emf.cdo.common.branch.CDOBranchManager;
 import org.eclipse.emf.cdo.common.branch.CDOBranchPoint;
+import org.eclipse.emf.cdo.common.branch.CDOBranchPointRange;
 import org.eclipse.emf.cdo.common.branch.CDOBranchVersion;
 import org.eclipse.emf.cdo.common.id.CDOID;
 import org.eclipse.emf.cdo.common.revision.CDORevision;
 import org.eclipse.emf.cdo.common.revision.CDORevisionCache;
 import org.eclipse.emf.cdo.common.revision.CDORevisionFactory;
+import org.eclipse.emf.cdo.common.revision.CDORevisionHandler;
 
 import org.eclipse.net4j.util.lifecycle.Lifecycle;
 
@@ -120,6 +123,7 @@ public abstract class DelegatingCDORevisionManager extends Lifecycle implements
   /**
    * @since 4.0
    */
+  @Deprecated
   @Override
   public void addRevision(CDORevision revision)
   {
@@ -127,6 +131,12 @@ public abstract class DelegatingCDORevisionManager extends Lifecycle implements
   }
 
   @Override
+  public CDORevision internRevision(CDORevision revision)
+  {
+    return getDelegate().internRevision(revision);
+  }
+
+  @Override
   public boolean containsRevision(CDOID id, CDOBranchPoint branchPoint)
   {
     return getDelegate().containsRevision(id, branchPoint);
@@ -145,6 +155,24 @@ public abstract class DelegatingCDORevisionManager extends Lifecycle implements
   }
 
   @Override
+  public EClass getObjectType(CDOID id, CDOBranchManager branchManagerForLoadOnDemand)
+  {
+    return getDelegate().getObjectType(id, branchManagerForLoadOnDemand);
+  }
+
+  @Override
+  public CDOBranchPointRange getObjectLifetime(CDOID id, CDOBranchPoint branchPoint)
+  {
+    return getDelegate().getObjectLifetime(id, branchPoint);
+  }
+
+  @Override
+  public InternalCDORevision getBaseRevision(CDORevision revision, int referenceChunk, boolean loadOnDemand)
+  {
+    return getDelegate().getBaseRevision(revision, referenceChunk, loadOnDemand);
+  }
+
+  @Override
   public InternalCDORevision getRevisionByVersion(CDOID id, CDOBranchVersion branchVersion, int referenceChunk, boolean loadOnDemand)
   {
     return getDelegate().getRevisionByVersion(id, branchVersion, referenceChunk, loadOnDemand);
@@ -177,6 +205,12 @@ public abstract class DelegatingCDORevisionManager extends Lifecycle implements
   }
 
   @Override
+  public void handleRevisions(EClass eClass, CDOBranch branch, boolean exactBranch, long timeStamp, boolean exactTime, CDORevisionHandler handler)
+  {
+    getDelegate().handleRevisions(eClass, branch, exactBranch, timeStamp, exactTime, handler);
+  }
+
+  @Override
   public void reviseLatest(CDOID id, CDOBranch branch)
   {
     getDelegate().reviseLatest(id, branch);
@@ -212,4 +246,17 @@ public abstract class DelegatingCDORevisionManager extends Lifecycle implements
   }
 
   protected abstract InternalCDORevisionManager getDelegate();
+
+  /**
+   * @author Eike Stepper
+   */
+  @SuppressWarnings("unused")
+  private static final class InternalCompletenessChecker extends DelegatingCDORevisionManager
+  {
+    @Override
+    protected InternalCDORevisionManager getDelegate()
+    {
+      return null;
+    }
+  }
 }
diff --git a/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/spi/common/revision/InternalCDORevisionCache.java b/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/spi/common/revision/InternalCDORevisionCache.java
index e8f931e6ab..5b190f562d 100644
--- a/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/spi/common/revision/InternalCDORevisionCache.java
+++ b/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/spi/common/revision/InternalCDORevisionCache.java
@@ -16,6 +16,7 @@ import org.eclipse.emf.cdo.common.id.CDOID;
 import org.eclipse.emf.cdo.common.revision.CDOAllRevisionsProvider;
 import org.eclipse.emf.cdo.common.revision.CDORevision;
 import org.eclipse.emf.cdo.common.revision.CDORevisionCache;
+import org.eclipse.emf.cdo.common.revision.CDORevisionInterner;
 
 import org.eclipse.net4j.util.lifecycle.ILifecycle;
 
@@ -29,7 +30,7 @@ import java.util.List;
  * @noextend This interface is not intended to be extended by clients.
  * @noimplement This interface is not intended to be implemented by clients.
  */
-public interface InternalCDORevisionCache extends CDORevisionCache, CDOAllRevisionsProvider, ILifecycle
+public interface InternalCDORevisionCache extends CDORevisionCache, CDORevisionInterner, CDOAllRevisionsProvider, ILifecycle
 {
   public InternalCDORevisionCache instantiate(CDORevision revision);
 
diff --git a/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/spi/common/revision/InternalCDORevisionManager.java b/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/spi/common/revision/InternalCDORevisionManager.java
index 64741770d1..cc3eea94d9 100644
--- a/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/spi/common/revision/InternalCDORevisionManager.java
+++ b/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/spi/common/revision/InternalCDORevisionManager.java
@@ -20,6 +20,7 @@ import org.eclipse.emf.cdo.common.revision.CDORevisionCache;
 import org.eclipse.emf.cdo.common.revision.CDORevisionCacheAdder;
 import org.eclipse.emf.cdo.common.revision.CDORevisionFactory;
 import org.eclipse.emf.cdo.common.revision.CDORevisionHandler;
+import org.eclipse.emf.cdo.common.revision.CDORevisionInterner;
 import org.eclipse.emf.cdo.common.revision.CDORevisionManager;
 
 import org.eclipse.net4j.util.lifecycle.ILifecycle;
@@ -36,7 +37,8 @@ import java.util.List;
  * @noimplement This interface is not intended to be implemented by clients.
  * @noextend This interface is not intended to be extended by clients.
  */
-public interface InternalCDORevisionManager extends CDORevisionManager, CDORevisionCacheAdder, ILifecycle
+@SuppressWarnings("deprecation")
+public interface InternalCDORevisionManager extends CDORevisionManager, CDORevisionInterner, CDORevisionCacheAdder, ILifecycle
 {
   /**
    * @since 4.0
diff --git a/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/spi/common/revision/RevisionInfo.java b/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/spi/common/revision/RevisionInfo.java
index 19e404de2d..9e74500835 100644
--- a/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/spi/common/revision/RevisionInfo.java
+++ b/plugins/org.eclipse.emf.cdo.common/src/org/eclipse/emf/cdo/spi/common/revision/RevisionInfo.java
@@ -168,6 +168,11 @@ public abstract class RevisionInfo
 
   public void processResult(InternalCDORevisionManager revisionManager, List<CDORevision> results, SyntheticCDORevision[] synthetics, int i)
   {
+    if (result != null)
+    {
+      result = (InternalCDORevision)revisionManager.internRevision(result);
+    }
+
     if (results != null)
     {
       if (result instanceof DetachedCDORevision)
@@ -180,14 +185,9 @@ public abstract class RevisionInfo
       }
     }
 
-    if (result != null)
-    {
-      revisionManager.addRevision(result);
-    }
-
     if (synthetic != null)
     {
-      revisionManager.addRevision(synthetic);
+      synthetic = (SyntheticCDORevision)revisionManager.internRevision(synthetic);
 
       if (synthetic instanceof PointerCDORevision)
       {
@@ -195,7 +195,7 @@ public abstract class RevisionInfo
         CDOBranchVersion target = pointer.getTarget();
         if (target != result && target instanceof InternalCDORevision)
         {
-          revisionManager.addRevision((CDORevision)target);
+          revisionManager.internRevision((CDORevision)target);
         }
       }
 
@@ -293,12 +293,14 @@ public abstract class RevisionInfo
       EClassifier classifier = in.readCDOClassifierRefAndResolve();
       long revised = in.readXLong();
       InternalCDORevision target = readResult(in, id, branch);
+
       // If target is null and we are in a Available RevisionInfo it means that we can use
       // availableBranchVersion/result as target
       if (target == null && result != null)
       {
         target = result;
       }
+
       return new PointerCDORevision((EClass)classifier, id, branch, revised, target);
     }