/**
  * Internally undo recorded changes we did so far.
  *
  * @return whether the state required undo actions
  */
 boolean undoChanges() {
   final State state = stateUpdater.getAndSet(this, State.ROLLBACK_ONLY);
   if (state == State.COMPLETED || state == State.ROLLBACK_ONLY) {
     // Was actually completed already
     return false;
   }
   PatchingTaskContext.Mode currentMode = this.mode;
   mode = PatchingTaskContext.Mode.UNDO;
   final PatchContentLoader loader = PatchContentLoader.create(miscBackup, null, null);
   // Undo changes for the identity
   undoChanges(identityEntry, loader);
   // TODO maybe check if we need to do something for the layers too !?
   if (state == State.INVALIDATE || currentMode == PatchingTaskContext.Mode.ROLLBACK) {
     // For apply the state needs to be invalidate
     // For rollback the files are invalidated as part of the tasks
     final PatchingTaskContext.Mode mode =
         currentMode == PatchingTaskContext.Mode.APPLY
             ? PatchingTaskContext.Mode.ROLLBACK
             : PatchingTaskContext.Mode.APPLY;
     for (final File file : moduleInvalidations) {
       try {
         PatchModuleInvalidationUtils.processFile(file, mode);
       } catch (Exception e) {
         PatchLogger.ROOT_LOGGER.debugf(e, "failed to restore state for %s", file);
       }
     }
   }
   return true;
 }
 /**
  * Complete the current operation and persist the current state to the disk. This will also
  * trigger the invalidation of outdated modules.
  *
  * @param modification the current modification
  * @param callback the completion callback
  */
 private void complete(
     final InstallationManager.InstallationModification modification,
     final FinalizeCallback callback) {
   final List<File> processed = new ArrayList<File>();
   try {
     try {
       // Update the state to invalidate and process module resources
       if (stateUpdater.compareAndSet(this, State.PREPARED, State.INVALIDATE)
           && mode == PatchingTaskContext.Mode.APPLY) {
         // Only invalidate modules when applying patches; on rollback files are immediately
         // restored
         for (final File invalidation : moduleInvalidations) {
           processed.add(invalidation);
           PatchModuleInvalidationUtils.processFile(invalidation, mode);
         }
       }
       modification.complete();
       callback.completed(this);
       state = State.COMPLETED;
     } catch (Exception e) {
       this.moduleInvalidations.clear();
       this.moduleInvalidations.addAll(processed);
       throw new RuntimeException(e);
     }
   } finally {
     if (state != State.COMPLETED) {
       try {
         modification.cancel();
       } finally {
         try {
           undoChanges();
         } finally {
           callback.operationCancelled(this);
         }
       }
     } else {
       try {
         if (checkForGarbageOnRestart) {
           final File cleanupMarker =
               new File(installedImage.getInstallationMetadata(), "cleanup-patching-dirs");
           cleanupMarker.createNewFile();
         }
       } catch (IOException e) {
         PatchLogger.ROOT_LOGGER.infof(e, "failed to create cleanup marker");
       }
     }
   }
 }
 @Override
 public void invalidateRoot(final File moduleRoot) throws IOException {
   final File[] files =
       moduleRoot.listFiles(
           new FilenameFilter() {
             @Override
             public boolean accept(File dir, String name) {
               return name.endsWith(".jar");
             }
           });
   if (files != null && files.length > 0) {
     for (final File file : files) {
       moduleInvalidations.add(file);
       if (mode == Mode.ROLLBACK) {
         // For rollback we need to restore the file before calculating the hash
         PatchModuleInvalidationUtils.processFile(file, mode);
       }
     }
   }
 }