Selection.java

/*
 * Copyright (C) 2008-2022 Mycila (mathieu.carbou@gmail.com)
 *
 * 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
 *
 *         https://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.mycila.maven.plugin.license.util;

import com.mycila.maven.plugin.license.Default;
import org.apache.maven.plugin.logging.Log;
import org.apache.maven.shared.utils.io.DirectoryScanner;
import org.apache.maven.shared.utils.io.MatchPatterns;
import org.apache.maven.shared.utils.io.ScanConductor;

import java.io.File;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

import static java.util.Arrays.asList;

/**
 * <b>Date:</b> 16-Feb-2008<br>
 * <b>Author:</b> Mathieu Carbou (mathieu.carbou@gmail.com)
 */
public final class Selection {

  private final File basedir;
  private final String[] included;
  private final String[] excluded;
  private final Log log;
  private final String[] userExcluded;

  private DirectoryScanner scanner;

  public Selection(File basedir, String[] included, String[] excluded, boolean useDefaultExcludes,
                   final Log log) {
    this.basedir = basedir;
    this.log = log;
    String[] overrides = buildOverrideInclusions(useDefaultExcludes, included);
    this.included = buildInclusions(included, overrides);
    this.userExcluded = excluded;
    this.excluded = buildExclusions(useDefaultExcludes, excluded, overrides);
  }

  public String[] getSelectedFiles() {
    scanIfneeded();
    return scanner.getIncludedFiles();
  }

  // for tests
  DirectoryScanner getScanner() {
    return scanner;
  }

  public File getBasedir() {
    return basedir;
  }

  public String[] getIncluded() {
    return included;
  }

  public String[] getExcluded() {
    return excluded;
  }

  private void scanIfneeded() {
    if (scanner == null) {
      final boolean debugEnabled = log.isDebugEnabled();
      final String[] folderExcludes = findFolderExcludes();
      final MatchPatterns excludePatterns = MatchPatterns.from(folderExcludes);
      if (debugEnabled) {
        log.debug("Starting to visit " + basedir + ", excluding directories: " + asList(folderExcludes));
      }
      scanner = new DirectoryScanner();
      scanner.setScanConductor(new ScanConductor() {
        @Override
        public ScanAction visitDirectory(final String name, final File directory) {
          if (excludePatterns.matches(name, true)) {
            return ScanAction.NO_RECURSE;
          }
          return ScanAction.CONTINUE;
        }

        @Override
        public ScanAction visitFile(final String name, final File file) {
          return ScanAction.CONTINUE;
        }
      });
      scanner.setBasedir(basedir);
      scanner.setIncludes(included);
      scanner.setExcludes(excluded);
      scanner.scan();
    }
  }

  private String[] findFolderExcludes() { // less we keep, less overhead we get so we only use user excludes there
    final List<String> excludes = new ArrayList<>(excluded.length / 2 /*estimate*/);
    for (final String exclude : (userExcluded != null ? userExcluded : excluded)) {
      if (isFolderExclusion(exclude)) {
        excludes.add(exclude);
      }
    }
    Collections.reverse(excludes); // assume user ones are more important than the set of defaults we appended
    return excludes.toArray(new String[0]);
  }

  private boolean isFolderExclusion(final String exclude) {
    return exclude.endsWith(File.separator + "**");
  }

  private static String[] buildExclusions(boolean useDefaultExcludes, String[] excludes, String[] overrides) {
    List<String> exclusions = new ArrayList<>();
    if (useDefaultExcludes) {
      exclusions.addAll(asList(Default.EXCLUDES));
    }
    // Remove from the default exclusion list the patterns that have been explicitly included
    for (String override : overrides) {
      exclusions.remove(override);
    }
    if (excludes != null && excludes.length > 0) {
      exclusions.addAll(asList(excludes));
    }
    return exclusions.toArray(new String[exclusions.size()]);
  }

  private static String[] buildInclusions(String[] includes, String[] overrides) {
    // if we use the default exclusion list, we just remove
    List<String> inclusions = new ArrayList<>(asList(includes != null && includes.length > 0 ? includes : Default.INCLUDE));
    inclusions.removeAll(asList(overrides));
    if (inclusions.isEmpty()) {
      inclusions.addAll(asList(Default.INCLUDE));
    }
    return inclusions.toArray(new String[inclusions.size()]);
  }

  private static String[] buildOverrideInclusions(boolean useDefaultExcludes, String[] includes) {
    // return the list of patterns that we have explicitly included when using default exclude list
    if (!useDefaultExcludes || includes == null || includes.length == 0) {
      return new String[0];
    }
    List<String> overrides = new ArrayList<>(asList(Default.EXCLUDES));
    overrides.retainAll(asList(includes));
    return overrides.toArray(new String[0]);
  }
}