code: /*
   * Copyright (c) 2016-present, RxJava Contributors.
   *
   * 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 io.reactivex.rxjava3.validators;
  
  import java.io.*;
  import java.net.URL;
  import java.util.*;
  
  import org.junit.Test;
  
  public class NoAnonymousInnerClassesTest {
  
      @Test
      public void verify() throws Exception {
          URL u = NoAnonymousInnerClassesTest.class.getResource("/");
          File f = new File(u.toURI());
  
          String fs = f.toString().toLowerCase().replace("\\", "/");
  
          System.out.println("Found " + fs);
  
          // running this particular test from IntelliJ will have the wrong class directory
          // gradle will generate test classes into a separate directory too
          int idx = fs.indexOf("/test");
          if (idx >= 0) {
              f = new File(fs.substring(0, idx));
          }
  
          StringBuilder b = new StringBuilder("Anonymous inner classes found:");
  
          Queue<File> queue = new ArrayDeque<>();
  
          queue.offer(f);
  
          String prefix = f.getAbsolutePath();
          int count = 0;
          while (!queue.isEmpty()) {
  
              f = queue.poll();
  
              if (f.isDirectory()) {
                  File[] dir = f.listFiles();
                  if (dir != null && dir.length != 0) {
                      for (File g : dir) {
                          queue.offer(g);
                      }
                  }
              } else {
                  String name = f.getName();
                  if (name.endsWith(".class") && name.contains("$")
                          && !name.contains("Perf") && !name.contains("Test")
                          && !name.startsWith("Test")) {
                      String baseName = name.substring(0, name.length() - 6);
                      String[] parts = name.split("\\$");
                      for (String s : parts) {
                          if (Character.isDigit(s.charAt(0))) {
                              String n = f.getAbsolutePath().substring(prefix.length()).replace('\\', '.').replace('/', '.');
                              if (n.startsWith(".")) {
                                  n = n.substring(1);
                              }
  
                              // javac generates switch-map anonymous classes with the same $x.class pattern
                              // we have to look into the file and search for $SwitchMap$
  
                              boolean found = false;
  
                              FileInputStream fin = new FileInputStream(f);
                              try {
                                  byte[] data = new byte[fin.available()];
                                  fin.read(data);
  
                                  String content = new String(data, "ISO-8859-1");
  
                                  if (content.contains("$SwitchMap$")) {
                                      // the parent class can reference these synthetic inner classes
                                      // and thus they also have $SwitchMap$
                                      // but the synthetic inner classes should not have further inner classes
  
                                      File[] filesInTheSameDir = f.getParentFile().listFiles();
  
                                      for (File fsame : filesInTheSameDir) {
                                          String fsameName = fsame.getName();
                                          if (fsameName.endsWith(".class")) {
                                              fsameName = fsameName.substring(0, fsameName.length() - 6);
  
                                              if (fsameName.startsWith(baseName)
                                                      && fsameName.length() > baseName.length() + 1
                                                      && fsameName.charAt(baseName.length()) == '$'
                                                      && Character.isDigit(fsameName.charAt(baseName.length() + 1))) {
                                                  found = true;
                                                  break;
                                              }
                                          }
                                      }
                                  } else {
                                      found = true;
                                  }
                              } finally {
                                  fin.close();
                              }
  
                              if (found) {
                                  b.append("\r\n").append(n);
                                  count++;
                                  break;
                              }
                          }
                      }
                  }
              }
          }
  
          if (count != 0) {
              throw new AssertionError(b.toString());
          }
      }
  }
  