com.github._1c_syntax.bsl.languageserver.cfg.ControlFlowGraphWalker Maven / Gradle / Ivy

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/*
 * This file is a part of BSL Language Server.
 *
 * Copyright (c) 2018-2022
 * Alexey Sosnoviy , Nikita Fedkin  and contributors
 *
 * SPDX-License-Identifier: LGPL-3.0-or-later
 *
 * BSL Language Server is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 3.0 of the License, or (at your option) any later version.
 *
 * BSL Language Server is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with BSL Language Server.
 */
package com.github._1c_syntax.bsl.languageserver.cfg;

import lombok.Getter;
import lombok.RequiredArgsConstructor;

import java.util.Set;

@RequiredArgsConstructor
public class ControlFlowGraphWalker {
  private final ControlFlowGraph graph;

  @Getter
  private CfgVertex currentNode;

  public void start() {
    currentNode = graph.getEntryPoint();
  }

  public Set availableRoutes() {
    return graph.outgoingEdgesOf(currentNode);
  }

  public CfgEdge walkNext() {
    var edges = availableRoutes();
    var edgeOrNot = edges.stream()
      .filter(x -> x.getType() == CfgEdgeType.DIRECT)
      .findFirst();

    if (edgeOrNot.isPresent()) {
      currentNode = graph.getEdgeTarget(edgeOrNot.get());
      return edgeOrNot.get();
    }

    throw new IllegalStateException("DIRECT edge is not found for node " + currentNode);
  }

  public CfgEdge walkNext(CfgEdgeType edgeType) {
    var edgeOrNot = availableRoutes().stream()
      .filter(x -> x.getType() == edgeType)
      .findAny();

    if(edgeOrNot.isPresent()) {
      currentNode = graph.getEdgeTarget(edgeOrNot.get());
      return edgeOrNot.get();
    }

    throw new IllegalStateException("Edge is not found for node " + currentNode);
  }

  public void walkTo(CfgVertex target) {
    currentNode = target;
  }

  public boolean isOnBranch() {
    return currentNode instanceof BranchingVertex;
  }
}