// Copyright (c) 2016, the R8 project authors. Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.
package com.android.tools.r8.dex;

import com.android.tools.r8.ByteBufferProvider;
import com.android.tools.r8.ByteDataView;
import com.android.tools.r8.DataDirectoryResource;
import com.android.tools.r8.DataEntryResource;
import com.android.tools.r8.DataResourceConsumer;
import com.android.tools.r8.DataResourceProvider;
import com.android.tools.r8.DataResourceProvider.Visitor;
import com.android.tools.r8.DexFilePerClassFileConsumer;
import com.android.tools.r8.DexIndexedConsumer;
import com.android.tools.r8.ProgramConsumer;
import com.android.tools.r8.ResourceException;
import com.android.tools.r8.code.Instruction;
import com.android.tools.r8.dex.FileWriter.ByteBufferResult;
import com.android.tools.r8.errors.CompilationError;
import com.android.tools.r8.features.FeatureSplitConfiguration.DataResourceProvidersAndConsumer;
import com.android.tools.r8.graph.AppServices;
import com.android.tools.r8.graph.AppView;
import com.android.tools.r8.graph.DexAnnotation;
import com.android.tools.r8.graph.DexAnnotationDirectory;
import com.android.tools.r8.graph.DexAnnotationSet;
import com.android.tools.r8.graph.DexApplication;
import com.android.tools.r8.graph.DexCallSite;
import com.android.tools.r8.graph.DexCode;
import com.android.tools.r8.graph.DexDebugInfo;
import com.android.tools.r8.graph.DexEncodedArray;
import com.android.tools.r8.graph.DexEncodedField;
import com.android.tools.r8.graph.DexEncodedMethod;
import com.android.tools.r8.graph.DexProgramClass;
import com.android.tools.r8.graph.DexString;
import com.android.tools.r8.graph.DexType;
import com.android.tools.r8.graph.DexTypeList;
import com.android.tools.r8.graph.DexValue;
import com.android.tools.r8.graph.EnclosingMethodAttribute;
import com.android.tools.r8.graph.GraphLens;
import com.android.tools.r8.graph.InitClassLens;
import com.android.tools.r8.graph.InnerClassAttribute;
import com.android.tools.r8.graph.ObjectToOffsetMapping;
import com.android.tools.r8.graph.ParameterAnnotationsList;
import com.android.tools.r8.naming.NamingLens;
import com.android.tools.r8.naming.ProguardMapSupplier;
import com.android.tools.r8.naming.ProguardMapSupplier.ProguardMapId;
import com.android.tools.r8.origin.Origin;
import com.android.tools.r8.shaking.MainDexClasses;
import com.android.tools.r8.utils.ArrayUtils;
import com.android.tools.r8.utils.DescriptorUtils;
import com.android.tools.r8.utils.ExceptionUtils;
import com.android.tools.r8.utils.InternalOptions;
import com.android.tools.r8.utils.PredicateUtils;
import com.android.tools.r8.utils.StringDiagnostic;
import com.android.tools.r8.utils.StringUtils;
import com.android.tools.r8.utils.ThreadUtils;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ObjectArrays;
import it.unimi.dsi.fastutil.objects.Reference2LongMap;
import it.unimi.dsi.fastutil.objects.Reference2LongOpenHashMap;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Collection;
import java.util.HashSet;
import java.util.IdentityHashMap;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Future;
import java.util.function.Predicate;
import java.util.stream.Collectors;

public class ApplicationWriter {

  public final AppView<?> appView;
  public final GraphLens graphLens;
  public final InitClassLens initClassLens;
  public final NamingLens namingLens;
  public final InternalOptions options;
  private final CodeToKeep desugaredLibraryCodeToKeep;
  private final Predicate<DexType> isTypeMissing;
  public List<Marker> markers;
  public List<DexString> markerStrings;

  public DexIndexedConsumer programConsumer;
  public final ProguardMapSupplier proguardMapSupplier;

  private static class SortAnnotations extends MixedSectionCollection {

    private final NamingLens namingLens;

    public SortAnnotations(NamingLens namingLens) {
      this.namingLens = namingLens;
    }

    @Override
    public boolean add(DexAnnotationSet dexAnnotationSet) {
      // Annotation sets are sorted by annotation types.
      dexAnnotationSet.sort(namingLens);
      return true;
    }

    @Override
    public boolean add(DexAnnotation annotation) {
      // The elements of encoded annotation must be sorted by name.
      annotation.annotation.sort();
      return true;
    }

    @Override
    public boolean add(DexEncodedArray dexEncodedArray) {
      // Dex values must potentially be sorted, eg, for DexValueAnnotation.
      for (DexValue value : dexEncodedArray.values) {
        value.sort();
      }
      return true;
    }

    @Override
    public boolean add(DexProgramClass dexClassData) {
      return true;
    }

    @Override
    public boolean add(DexCode dexCode) {
      return true;
    }

    @Override
    public boolean add(DexDebugInfo dexDebugInfo) {
      return true;
    }

    @Override
    public boolean add(DexTypeList dexTypeList) {
      return true;
    }

    @Override
    public boolean add(ParameterAnnotationsList parameterAnnotationsList) {
      return true;
    }

    @Override
    public boolean setAnnotationsDirectoryForClass(DexProgramClass clazz,
        DexAnnotationDirectory annotationDirectory) {
      return true;
    }
  }

  public ApplicationWriter(
      AppView<?> appView,
      List<Marker> markers,
      GraphLens graphLens,
      InitClassLens initClassLens,
      NamingLens namingLens,
      ProguardMapSupplier proguardMapSupplier) {
    this(
        appView,
        markers,
        graphLens,
        initClassLens,
        namingLens,
        proguardMapSupplier,
        null);
  }

  public ApplicationWriter(
      AppView<?> appView,
      List<Marker> markers,
      GraphLens graphLens,
      InitClassLens initClassLens,
      NamingLens namingLens,
      ProguardMapSupplier proguardMapSupplier,
      DexIndexedConsumer consumer) {
    this.appView = appView;
    this.options = appView.options();
    this.desugaredLibraryCodeToKeep = CodeToKeep.createCodeToKeep(options, namingLens);
    this.markers = markers;
    this.graphLens = graphLens;
    this.initClassLens = initClassLens;
    this.namingLens = namingLens;
    this.proguardMapSupplier = proguardMapSupplier;
    this.programConsumer = consumer;
    this.isTypeMissing =
        PredicateUtils.isNull(appView.appInfo()::definitionForWithoutExistenceAssert);
  }

  private List<VirtualFile> distribute(ExecutorService executorService)
      throws ExecutionException, IOException {
    // Distribute classes into dex files.
    VirtualFile.Distributor distributor;
    if (options.isGeneratingDexFilePerClassFile()) {
      distributor = new VirtualFile.FilePerInputClassDistributor(this,
          options.getDexFilePerClassFileConsumer().combineSyntheticClassesWithPrimaryClass());
    } else if (!options.canUseMultidex()
        && options.mainDexKeepRules.isEmpty()
        && appView.appInfo().getMainDexClasses().isEmpty()
        && options.enableMainDexListCheck) {
      distributor = new VirtualFile.MonoDexDistributor(this, options);
    } else {
      distributor = new VirtualFile.FillFilesDistributor(this, options, executorService);
    }
    return distributor.run();
  }

  /**
   * For each class within a virtual file, this function insert a string that contains the
   * checksum information about that class.
   *
   * This needs to be done after distribute but before dex string sorting.
   */
  private void encodeChecksums(Iterable<VirtualFile> files) {
    Collection<DexProgramClass> classes = appView.appInfo().classes();
    Reference2LongMap<DexString> inputChecksums = new Reference2LongOpenHashMap<>(classes.size());
    for (DexProgramClass clazz : classes) {
      inputChecksums.put(clazz.getType().descriptor, clazz.getChecksum());
    }
    for (VirtualFile file : files) {
      ClassesChecksum toWrite = new ClassesChecksum();
      for (DexProgramClass clazz : file.classes()) {
        DexString desc = clazz.type.descriptor;
        toWrite.addChecksum(desc.toString(), inputChecksums.getLong(desc));
      }
      file.injectString(appView.dexItemFactory().createString(toWrite.toJsonString()));
    }
  }

  public void write(ExecutorService executorService) throws IOException, ExecutionException {
    appView.appInfo().app().timing.begin("DexApplication.write");
    ProguardMapId proguardMapId = null;
    if (proguardMapSupplier != null && options.proguardMapConsumer != null) {
      proguardMapId = proguardMapSupplier.writeProguardMap();
    }

    // If we do have a map then we're called from R8. In that case we have at least one marker.
    assert proguardMapId == null || (markers != null && markers.size() >= 1);

    if (markers != null && !markers.isEmpty()) {
      if (proguardMapId != null) {
        markers.get(0).setPgMapId(proguardMapId.get());
      }
      markerStrings = new ArrayList<>(markers.size());
      for (Marker marker : markers) {
        markerStrings.add(appView.dexItemFactory().createString(marker.toString()));
      }
    }
    try {
      // TODO(b/151313715): Move this to the writer threads.
      insertAttributeAnnotations();

      // Each DexCallSite must have its instruction offset set for sorting.
      if (options.isGeneratingDex()) {
        setCallSiteContexts(executorService);
      }

      // Generate the dex file contents.
      List<Future<Boolean>> dexDataFutures = new ArrayList<>();
      List<VirtualFile> virtualFiles = distribute(executorService);
      if (options.encodeChecksums) {
        encodeChecksums(virtualFiles);
      }
      assert markers == null
          || markers.isEmpty()
          || appView.dexItemFactory().extractMarkers() != null;
      assert appView.withProtoShrinker(
          shrinker -> virtualFiles.stream().allMatch(shrinker::verifyDeadProtoTypesNotReferenced),
          true);

      // TODO(b/151313617): Sorting annotations mutates elements so run single threaded on main.
      SortAnnotations sortAnnotations = new SortAnnotations(namingLens);
      appView.appInfo().classes().forEach((clazz) -> clazz.addDependencies(sortAnnotations));

      for (VirtualFile virtualFile : virtualFiles) {
        if (virtualFile.isEmpty()) {
          continue;
        }
        dexDataFutures.add(
            executorService.submit(
                () -> {
                  ProgramConsumer consumer;
                  ByteBufferProvider byteBufferProvider;
                  if (programConsumer != null) {
                    consumer = programConsumer;
                    byteBufferProvider = programConsumer;
                  } else if (virtualFile.getPrimaryClassDescriptor() != null) {
                    consumer = options.getDexFilePerClassFileConsumer();
                    byteBufferProvider = options.getDexFilePerClassFileConsumer();
                  } else {
                    if (virtualFile.getFeatureSplit() != null) {
                      ProgramConsumer featureConsumer =
                          virtualFile.getFeatureSplit().getProgramConsumer();
                      assert featureConsumer instanceof DexIndexedConsumer;
                      consumer = featureConsumer;
                      byteBufferProvider = (DexIndexedConsumer) featureConsumer;
                    } else {
                      consumer = options.getDexIndexedConsumer();
                      byteBufferProvider = options.getDexIndexedConsumer();
                    }
                  }
                  ObjectToOffsetMapping objectMapping =
                      virtualFile.computeMapping(
                          appView.appInfo(), graphLens, namingLens, initClassLens);
                  MethodToCodeObjectMapping codeMapping =
                      rewriteCodeWithJumboStrings(
                          objectMapping, virtualFile.classes(), appView.appInfo().app());
                  ByteBufferResult result =
                      writeDexFile(objectMapping, codeMapping, byteBufferProvider);
                  ByteDataView data =
                      new ByteDataView(
                          result.buffer.array(), result.buffer.arrayOffset(), result.length);
                  if (consumer instanceof DexFilePerClassFileConsumer) {
                    ((DexFilePerClassFileConsumer) consumer)
                        .accept(
                            virtualFile.getPrimaryClassDescriptor(),
                            data,
                            virtualFile.getClassDescriptors(),
                            options.reporter);
                  } else {
                    ((DexIndexedConsumer) consumer)
                        .accept(
                            virtualFile.getId(),
                            data,
                            virtualFile.getClassDescriptors(),
                            options.reporter);
                  }
                  // Release use of the backing buffer now that accept has returned.
                  data.invalidate();
                  byteBufferProvider.releaseByteBuffer(result.buffer.asByteBuffer());
                  return true;
                }));
      }
      // Wait for all files to be processed before moving on.
      ThreadUtils.awaitFutures(dexDataFutures);
      // A consumer can manage the generated keep rules.
      if (options.desugaredLibraryKeepRuleConsumer != null && !desugaredLibraryCodeToKeep.isNop()) {
        assert !options.isDesugaredLibraryCompilation();
        desugaredLibraryCodeToKeep.generateKeepRules(options);
      }
      // Fail if there are pending errors, e.g., the program consumers may have reported errors.
      options.reporter.failIfPendingErrors();
      // Supply info to all additional resource consumers.
      supplyAdditionalConsumers(appView.appInfo().app(), appView, graphLens, namingLens, options);
    } finally {
      appView.appInfo().app().timing.end();
    }
  }

  public static void supplyAdditionalConsumers(
      DexApplication application,
      AppView<?> appView,
      GraphLens graphLens,
      NamingLens namingLens,
      InternalOptions options) {
    if (options.configurationConsumer != null) {
      ExceptionUtils.withConsumeResourceHandler(
          options.reporter, options.configurationConsumer,
          options.getProguardConfiguration().getParsedConfiguration());
      ExceptionUtils.withFinishedResourceHandler(options.reporter, options.configurationConsumer);
    }
    if (options.mainDexListConsumer != null) {
      ExceptionUtils.withConsumeResourceHandler(
          options.reporter, options.mainDexListConsumer, writeMainDexList(appView, namingLens));
      ExceptionUtils.withFinishedResourceHandler(options.reporter, options.mainDexListConsumer);
    }

    DataResourceConsumer dataResourceConsumer = options.dataResourceConsumer;
    if (dataResourceConsumer != null) {
      ImmutableList<DataResourceProvider> dataResourceProviders = application.dataResourceProviders;
      ResourceAdapter resourceAdapter =
          new ResourceAdapter(appView, application.dexItemFactory, graphLens, namingLens, options);

      adaptAndPassDataResources(
          options, dataResourceConsumer, dataResourceProviders, resourceAdapter);

      // Write the META-INF/services resources. Sort on service names and keep the order from
      // the input for the implementation lines for deterministic output.
      if (!appView.appServices().isEmpty()) {
        appView
            .appServices()
            .visit(
                (DexType service, List<DexType> implementations) -> {
                  String serviceName =
                      DescriptorUtils.descriptorToJavaType(
                          namingLens.lookupDescriptor(service).toString());
                  dataResourceConsumer.accept(
                      DataEntryResource.fromBytes(
                          StringUtils.lines(
                                  implementations.stream()
                                      .map(namingLens::lookupDescriptor)
                                      .map(DexString::toString)
                                      .map(DescriptorUtils::descriptorToJavaType)
                                      .collect(Collectors.toList()))
                              .getBytes(),
                          AppServices.SERVICE_DIRECTORY_NAME + serviceName,
                          Origin.unknown()),
                      options.reporter);
                });
      }
    }

    if (options.featureSplitConfiguration != null) {
      for (DataResourceProvidersAndConsumer entry :
          options.featureSplitConfiguration.getDataResourceProvidersAndConsumers()) {
        ResourceAdapter resourceAdapter =
            new ResourceAdapter(
                appView, application.dexItemFactory, graphLens, namingLens, options);
        adaptAndPassDataResources(
            options, entry.getConsumer(), entry.getProviders(), resourceAdapter);
      }
    }
  }

  private static void adaptAndPassDataResources(
      InternalOptions options,
      DataResourceConsumer dataResourceConsumer,
      Collection<DataResourceProvider> dataResourceProviders,
      ResourceAdapter resourceAdapter) {
    Set<String> generatedResourceNames = new HashSet<>();

    for (DataResourceProvider dataResourceProvider : dataResourceProviders) {
      try {
        dataResourceProvider.accept(
            new Visitor() {
              @Override
              public void visit(DataDirectoryResource directory) {
                DataDirectoryResource adapted = resourceAdapter.adaptIfNeeded(directory);
                if (adapted != null) {
                  dataResourceConsumer.accept(adapted, options.reporter);
                  options.reporter.failIfPendingErrors();
                }
              }

              @Override
              public void visit(DataEntryResource file) {
                if (resourceAdapter.isService(file)) {
                  // META-INF/services resources are handled below.
                  return;
                }

                DataEntryResource adapted = resourceAdapter.adaptIfNeeded(file);
                if (generatedResourceNames.add(adapted.getName())) {
                  dataResourceConsumer.accept(adapted, options.reporter);
                } else {
                  options.reporter.warning(
                      new StringDiagnostic("Resource '" + file.getName() + "' already exists."));
                }
                options.reporter.failIfPendingErrors();
              }
            });
      } catch (ResourceException e) {
        throw new CompilationError(e.getMessage(), e);
      }
    }
  }

  private void insertAttributeAnnotations() {
    // Convert inner-class attributes to DEX annotations
    for (DexProgramClass clazz : appView.appInfo().classes()) {
      insertAttributeAnnotationsForClass(clazz);
      clazz.fields().forEach(this::insertAttributeAnnotationsForField);
    }
  }

  private void insertAttributeAnnotationsForClass(DexProgramClass clazz) {
    EnclosingMethodAttribute enclosingMethod = clazz.getEnclosingMethodAttribute();
    List<InnerClassAttribute> innerClasses = clazz.getInnerClasses();
    if (enclosingMethod == null
        && innerClasses.isEmpty()
        && clazz.getClassSignature().hasNoSignature()) {
      return;
    }

    // EnclosingMember translates directly to an enclosing class/method if present.
    List<DexAnnotation> annotations = new ArrayList<>(2 + innerClasses.size());
    if (enclosingMethod != null) {
      if (enclosingMethod.getEnclosingMethod() != null) {
        annotations.add(
            DexAnnotation.createEnclosingMethodAnnotation(
                enclosingMethod.getEnclosingMethod(), options.itemFactory));
      } else {
        // At this point DEX can't distinguish between local classes and member classes based on
        // the enclosing class annotation itself.
        annotations.add(
            DexAnnotation.createEnclosingClassAnnotation(
                enclosingMethod.getEnclosingClass(), options.itemFactory));
      }
    }

    // Each inner-class entry becomes a inner-class (or inner-class & enclosing-class pair) if
    // it relates to the present class. If it relates to the outer-type (and is named) it becomes
    // part of the member-classes annotation.
    if (!innerClasses.isEmpty()) {
      List<DexType> memberClasses = new ArrayList<>(innerClasses.size());
      for (InnerClassAttribute innerClass : innerClasses) {
        if (clazz.type == innerClass.getInner()) {
          if (enclosingMethod == null
              && (innerClass.getOuter() == null || innerClass.isAnonymous())) {
            options.warningMissingEnclosingMember(
                clazz.type, clazz.origin, clazz.getInitialClassFileVersion());
          } else {
            annotations.add(
                DexAnnotation.createInnerClassAnnotation(
                    namingLens.lookupInnerName(innerClass, options),
                    innerClass.getAccess(),
                    options.itemFactory));
            if (innerClass.getOuter() != null && innerClass.isNamed()) {
              annotations.add(
                  DexAnnotation.createEnclosingClassAnnotation(
                      innerClass.getOuter(), options.itemFactory));
            }
          }
        } else if (clazz.type == innerClass.getOuter() && innerClass.isNamed()) {
          memberClasses.add(innerClass.getInner());
        }
      }
      if (!memberClasses.isEmpty()) {
        annotations.add(
            DexAnnotation.createMemberClassesAnnotation(memberClasses, options.itemFactory));
      }
    }

    if (clazz.getClassSignature().hasSignature()) {
      annotations.add(
          DexAnnotation.createSignatureAnnotation(
              clazz.getClassSignature().toRenamedString(namingLens, isTypeMissing),
              options.itemFactory));
    }

    if (!annotations.isEmpty()) {
      // Append the annotations to annotations array of the class.
      DexAnnotation[] copy =
          ObjectArrays.concat(
              clazz.annotations().annotations,
              annotations.toArray(DexAnnotation.EMPTY_ARRAY),
              DexAnnotation.class);
      clazz.setAnnotations(new DexAnnotationSet(copy));
    }

    // Clear the attribute structures now that they are represented in annotations.
    clazz.clearEnclosingMethodAttribute();
    clazz.clearInnerClasses();
    clazz.clearClassSignature();
  }

  private void insertAttributeAnnotationsForField(DexEncodedField field) {
    if (field.getFieldSignature().hasNoSignature()) {
      return;
    }
    // Append the annotations to annotations array of the class.
    field.setAnnotations(
        new DexAnnotationSet(
            ArrayUtils.appendSingleElement(
                field.annotations().annotations,
                DexAnnotation.createSignatureAnnotation(
                    field.getFieldSignature().toRenamedString(namingLens, isTypeMissing),
                    options.itemFactory))));
    field.clearFieldSignature();
  }

  private void setCallSiteContexts(ExecutorService executorService) throws ExecutionException {
    ThreadUtils.processItems(
        appView.appInfo().classes(), this::setCallSiteContexts, executorService);
  }

  private void setCallSiteContexts(DexProgramClass clazz) {
    for (DexEncodedMethod method : clazz.methods()) {
      if (method.hasCode()) {
        DexCode code = method.getCode().asDexCode();
        assert code != null;
        for (Instruction instruction : code.instructions) {
          DexCallSite callSite = instruction.getCallSite();
          if (callSite != null) {
            callSite.setContext(method.getReference(), instruction.getOffset());
          }
        }
      }
    }
  }

  /**
   * Rewrites the code for all methods in the given file so that they use JumboString for at least
   * the strings that require it in mapping.
   *
   * <p>If run multiple times on a class, the lowest index that is required to be a JumboString will
   * be used.
   */
  private MethodToCodeObjectMapping rewriteCodeWithJumboStrings(
      ObjectToOffsetMapping mapping,
      Collection<DexProgramClass> classes,
      DexApplication application) {
    // Do not bail out early if forcing jumbo string processing.
    if (!options.testing.forceJumboStringProcessing) {
      // If there are no strings with jumbo indices at all this is a no-op.
      if (!mapping.hasJumboStrings()) {
        return MethodToCodeObjectMapping.fromMethodBacking();
      }
      // If the globally highest sorting string is not a jumbo string this is also a no-op.
      if (application.highestSortingString != null &&
          application.highestSortingString.slowCompareTo(mapping.getFirstJumboString()) < 0) {
        return MethodToCodeObjectMapping.fromMethodBacking();
      }
    }
    // At least one method needs a jumbo string in which case we construct a thread local mapping
    // for all code objects and write the processed results into that map.
    Map<DexEncodedMethod, DexCode> codeMapping = new IdentityHashMap<>();
    for (DexProgramClass clazz : classes) {
      boolean isSharedSynthetic = clazz.getSynthesizedFrom().size() > 1;
      clazz.forEachMethod(
          method -> {
            DexCode code =
                method.rewriteCodeWithJumboStrings(
                    mapping,
                    application.dexItemFactory,
                    options.testing.forceJumboStringProcessing);
            codeMapping.put(method, code);
            if (!isSharedSynthetic) {
              // If the class is not a shared class the mapping now has ownership of the methods
              // code object. This ensures freeing of code resources once the map entry is cleared
              // and also ensures that we don't end up using the incorrect code pointer again later!
              method.removeCode();
            }
          });
    }
    return MethodToCodeObjectMapping.fromMapBacking(codeMapping);
  }

  private ByteBufferResult writeDexFile(
      ObjectToOffsetMapping objectMapping,
      MethodToCodeObjectMapping codeMapping,
      ByteBufferProvider provider) {
    FileWriter fileWriter =
        new FileWriter(
            provider,
            objectMapping,
            codeMapping,
            appView.appInfo().app(),
            options,
            namingLens,
            desugaredLibraryCodeToKeep);
    // Collect the non-fixed sections.
    fileWriter.collect();
    // Generate and write the bytes.
    return fileWriter.generate();
  }

  private static String mapMainDexListName(DexType type, NamingLens namingLens) {
    return DescriptorUtils.descriptorToJavaType(namingLens.lookupDescriptor(type).toString())
        .replace('.', '/') + ".class";
  }

  private static String writeMainDexList(AppView<?> appView, NamingLens namingLens) {
    MainDexClasses mainDexClasses = appView.appInfo().getMainDexClasses();
    StringBuilder builder = new StringBuilder();
    List<DexType> list = new ArrayList<>(mainDexClasses.size());
    mainDexClasses.forEach(list::add);
    list.sort(DexType::slowCompareTo);
    list.forEach(
        type -> builder.append(mapMainDexListName(type, namingLens)).append('\n'));
    return builder.toString();
  }
}