content: /*
   *  Licensed to the Apache Software Foundation (ASF) under one or more
   *  contributor license agreements.  See the NOTICE file distributed with
   *  this work for additional information regarding copyright ownership.
   *  The ASF licenses this file to You 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 org.apache.ivy.core.sort;
  
  import java.util.Collection;
  import java.util.LinkedList;
  import java.util.List;
  
  import org.apache.ivy.core.module.descriptor.DependencyDescriptor;
  import org.apache.ivy.core.module.descriptor.ModuleDescriptor;
  import org.apache.ivy.plugins.circular.CircularDependencyException;
  import org.apache.ivy.plugins.circular.CircularDependencyStrategy;
  import org.apache.ivy.plugins.version.VersionMatcher;
  import org.apache.ivy.util.Message;
  
  /**
   * Inner helper class for sorting ModuleDescriptors.
   * <p>
   * ModuleDescriptorSorter use CollectionOfModulesToSort to find the dependencies of the modules, and
   * use ModuleInSort to store some temporary values attached to the modules to sort.
   * </p>
   *
   * @see ModuleInSort
   * @see CollectionOfModulesToSort
   */
  public class ModuleDescriptorSorter {
  
      private final CollectionOfModulesToSort moduleDescriptors;
  
      private final List<ModuleDescriptor> sorted = new LinkedList<>();
  
      private final CircularDependencyStrategy circularDepStrategy;
  
      public ModuleDescriptorSorter(Collection<ModuleDescriptor> modulesDescriptorsToSort,
              VersionMatcher matcher, NonMatchingVersionReporter nonMatchingVersionReporter,
              CircularDependencyStrategy circularDepStrategy) {
          this.circularDepStrategy = circularDepStrategy;
          moduleDescriptors = new CollectionOfModulesToSort(modulesDescriptorsToSort, matcher,
                  nonMatchingVersionReporter);
      }
  
      /**
       * Iterates over all modules calling sortModuleDescriptorsHelp.
       *
       * @return sorted module
       * @throws CircularDependencyException somehow
       */
      public List<ModuleDescriptor> sortModuleDescriptors() throws CircularDependencyException {
          Message.debug("Nbr of module to sort : " + moduleDescriptors.size());
          for (ModuleInSort m : moduleDescriptors) {
              sortModuleDescriptorsHelp(m, m);
          }
          return sorted;
      }
  
      /**
       * If current module has already been added to list, returns, Otherwise invokes
       * sortModuleDescriptorsHelp for all dependencies contained within set of moduleDescriptors.
       * Then finally adds self to list of sorted.<br/>
       * When a loop is detected by a recursive call, the moduleDescriptors are not added immediately
       * added to the sorted list. They are added as loop dependencies of the root, and will be added
       * to the sorted list only when the root itself will be added.
       *
       * @param current
       *            Current module to add to sorted list.
       * @throws CircularDependencyException somehow
       */
      private void sortModuleDescriptorsHelp(ModuleInSort current, ModuleInSort caller)
              throws CircularDependencyException {
          // if already sorted return
          if (current.isProcessed()) {
              return;
          }
          if (current.checkLoop(caller, circularDepStrategy)) {
              return;
          }
          DependencyDescriptor[] descriptors = current.getDependencies();
          Message.debug("Sort dependencies of : " + current.toString()
                  + " / Number of dependencies = " + descriptors.length);
          current.setCaller(caller);
          for (DependencyDescriptor descriptor : descriptors) {
              ModuleInSort child = moduleDescriptors.getModuleDescriptorDependency(descriptor);
              if (child != null) {
                  sortModuleDescriptorsHelp(child, current);
              }
          }
          current.endOfCall();
          Message.debug("Sort done for : " + current.toString());
          current.addToSortedListIfRequired(sorted);
      }
  
  }
  