platform/vcs-log/graph/src/com/intellij/vcs/log/newgraph/utils/DfsUtil.java

/*
 * Copyright 2000-2014 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.vcs.log.newgraph.utils;

import org.jetbrains.annotations.NotNull;

public class DfsUtil {
  private final int[] myStack;

  public DfsUtil(int maxStackSize) {
    myStack = new int[maxStackSize];
  }

  public interface NextNode {
    int NODE_NOT_FOUND = -1;

    int fun(int currentNode);
  }

  public void nodeDfsIterator(int startRowIndex, @NotNull NextNode nextNodeFun) {
    myStack[0] = startRowIndex;
    int stackIndex = 0;

    while (stackIndex >= 0) {
      int nextNode = nextNodeFun.fun(myStack[stackIndex]);
      if (nextNode != NextNode.NODE_NOT_FOUND) {
        stackIndex++;
        myStack[stackIndex] = nextNode;
      } else {
        stackIndex--;
      }
    }
  }
}