platform/core-impl/src/com/intellij/psi/impl/AbstractModificationTracker.java

/*
 * Copyright 2000-2013 JetBrains s.r.o.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.intellij.psi.impl;

import com.intellij.psi.PsiElement;
import com.intellij.psi.PsiFile;
import org.jetbrains.annotations.NotNull;

/**
 * @author Roman.Chernyatchik
 */
public abstract class AbstractModificationTracker implements PsiTreeChangePreprocessor {
  private final PsiManagerImpl myPsiManager;
  private PsiModificationTrackerImpl myModificationTracker;

  protected abstract boolean isInsideCodeBlock(PsiElement element);

  public AbstractModificationTracker(PsiManagerImpl psiManager) {
    myPsiManager = psiManager;
  }

  public PsiManagerImpl getPsiManager() {
    return myPsiManager;
  }

  protected void initTracker() {
    myModificationTracker = (PsiModificationTrackerImpl) myPsiManager.getModificationTracker();
    myPsiManager.addTreeChangePreprocessor(this);
  }

  @Override
  public void treeChanged(@NotNull final PsiTreeChangeEventImpl event) {
    boolean changedInsideCodeBlock = false;

    switch (event.getCode()) {
      case BEFORE_CHILDREN_CHANGE:
        if (event.getParent() instanceof PsiFile) {
          changedInsideCodeBlock = true;
          break; // May be caused by fake PSI event from PomTransaction. A real event will anyway follow.
        }

      case CHILDREN_CHANGED :
        if (event.isGenericChange()) return;
        changedInsideCodeBlock = isInsideCodeBlock(event.getParent());
      break;

      case BEFORE_CHILD_ADDITION:
      case BEFORE_CHILD_REMOVAL:
      case CHILD_ADDED :
      case CHILD_REMOVED :
      case BEFORE_CHILD_REPLACEMENT:
      case CHILD_REPLACED :
        changedInsideCodeBlock = isInsideCodeBlock(event.getParent()) &&
                                 isInsideCodeBlock(event.getChild()) &&
                                 isInsideCodeBlock(event.getOldChild()) &&
                                 isInsideCodeBlock(event.getNewChild());
      break;

      case BEFORE_CHILD_MOVEMENT:
      case CHILD_MOVED :
        changedInsideCodeBlock = isInsideCodeBlock(event.getOldParent()) && isInsideCodeBlock(event.getNewParent()) && isInsideCodeBlock(event.getChild());
      break;

      case BEFORE_PROPERTY_CHANGE:
      case PROPERTY_CHANGED :
        changedInsideCodeBlock = false;
      break;
   }

    if (!changedInsideCodeBlock) {
      processOutOfCodeBlockModification(event);
    }
  }

  protected void processOutOfCodeBlockModification(final PsiTreeChangeEventImpl event) {
    myModificationTracker.incOutOfCodeBlockModificationCounter();
  }
}