com.github.ferstl.depgraph.dependency.GraphBuildingVisitor Maven / Gradle / Ivy

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This Maven plugin generates dependency graphs on single modules or in an aggregated form on multi-module projects. The graphs are represented by .dot files. In case that Graphviz is installed on the machine where this plugin is run, the .dot file can be directly converted into all supported image files.

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/*
 * Copyright (c) 2014 - 2017 the original author or authors.
 *
 * 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.github.ferstl.depgraph.dependency;

import java.util.ArrayDeque;
import java.util.Deque;
import java.util.Set;
import org.apache.maven.artifact.Artifact;
import org.apache.maven.artifact.resolver.filter.ArtifactFilter;
import com.github.ferstl.depgraph.graph.GraphBuilder;

import static java.util.EnumSet.allOf;


/**
 * A node visitor that creates edges between the visited nodes using a {@link GraphBuilder}. This class implements the
 * {@code DependencyNodeVisitor} interfaces for dependency trees and dependency graphs and adapts the different node
 * instances using {@link DependencyNode}.
 */
class GraphBuildingVisitor implements org.apache.maven.shared.dependency.graph.traversal.DependencyNodeVisitor, org.apache.maven.shared.dependency.tree.traversal.DependencyNodeVisitor {

  private final GraphBuilder graphBuilder;
  private final boolean omitReachablePaths;
  private final Deque nodeStack;
  private final ArtifactFilter globalFilter;
  private final ArtifactFilter transitiveFilter;
  private final ArtifactFilter targetFilter;
  private final Set includedResolutions;

  /**
   * Max depth of the graph. Nodes deeper than this depth will be cut off from the graph.
   */
  private int cutOffDepth = 0;

  GraphBuildingVisitor(GraphBuilder graphBuilder, ArtifactFilter globalFilter, ArtifactFilter transitiveFilter, ArtifactFilter targetFilter, Set includedResolutions) {
    this(graphBuilder, globalFilter, transitiveFilter, targetFilter, includedResolutions, false);
  }

  GraphBuildingVisitor(GraphBuilder graphBuilder, ArtifactFilter transitiveFilter, ArtifactFilter targetFilter, boolean omitReachablePaths) {
    this(graphBuilder, DoNothingArtifactFilter.INSTANCE, transitiveFilter, targetFilter, allOf(NodeResolution.class), omitReachablePaths);
  }

  private GraphBuildingVisitor(GraphBuilder graphBuilder, ArtifactFilter globalFilter, ArtifactFilter transitiveFilter, ArtifactFilter targetFilter, Set includedResolutions, boolean omitReachablePaths) {
    this.graphBuilder = graphBuilder;
    this.omitReachablePaths = omitReachablePaths;
    this.nodeStack = new ArrayDeque<>();
    this.globalFilter = globalFilter;
    this.transitiveFilter = transitiveFilter;
    this.targetFilter = targetFilter;
    this.includedResolutions = includedResolutions;
  }

  @Override
  public boolean visit(org.apache.maven.shared.dependency.graph.DependencyNode node) {
    return internalVisit(new DependencyNode(node));
  }

  @Override
  public boolean endVisit(org.apache.maven.shared.dependency.graph.DependencyNode node) {
    return internalEndVisit(new DependencyNode(node));
  }

  @Override
  public boolean visit(org.apache.maven.shared.dependency.tree.DependencyNode node) {
    return internalVisit(new DependencyNode(node));
  }

  @Override
  public boolean endVisit(org.apache.maven.shared.dependency.tree.DependencyNode node) {
    return internalEndVisit(new DependencyNode(node));
  }

  private boolean internalVisit(DependencyNode node) {
    if (!isIncluded(node)) {
      return false;
    }

    this.nodeStack.push(node);

    if (this.targetFilter.include(node.getArtifact())) {
      this.cutOffDepth = this.nodeStack.size();
    }

    return true;
  }


  private boolean internalEndVisit(DependencyNode node) {
    if (!isIncluded(node)) {
      return true;
    }

    this.nodeStack.pop();

    DependencyNode currentParent = this.nodeStack.peek();
    if (this.nodeStack.size() < this.cutOffDepth) {
      this.cutOffDepth = this.nodeStack.size();

      if (currentParent != null) {
        mergeWithExisting(node);

        // If omitReachablePaths is set, don't add an edge if there already is an existing path between the nodes.
        // An exception to that are test dependencies which are not resolved transitively.
        if (!this.omitReachablePaths || !this.graphBuilder.isReachable(node, currentParent) || "test".equals(node.getArtifact().getScope())) {
          this.graphBuilder.addEdge(currentParent, node);
        } else {
          this.graphBuilder.addNode(node);
        }
      }
    }

    return true;
  }

  private boolean isIncluded(DependencyNode node) {
    Artifact artifact = node.getArtifact();

    return this.globalFilter.include(artifact)
        && this.transitiveFilter.include(artifact)
        && this.includedResolutions.contains(node.getResolution());
  }

  private void mergeWithExisting(DependencyNode node) {
    DependencyNode effectiveNode = this.graphBuilder.getEffectiveNode(node);
    node.merge(effectiveNode);
  }

  private enum DoNothingArtifactFilter implements ArtifactFilter {
    INSTANCE;

    @Override
    public boolean include(Artifact artifact) {
      return true;
    }

  }
}