content: /*
   * Copyright (c) 2016, Oracle and/or its affiliates. All rights reserved.
   * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   *
   * This code is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License version 2 only, as
   * published by the Free Software Foundation.  Oracle designates this
   * particular file as subject to the "Classpath" exception as provided
   * by Oracle in the LICENSE file that accompanied this code.
   *
   * This code is distributed in the hope that it will be useful, but WITHOUT
   * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
   * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
   * version 2 for more details (a copy is included in the LICENSE file that
   * accompanied this code).
   *
   * You should have received a copy of the GNU General Public License version
   * 2 along with this work; if not, write to the Free Software Foundation,
   * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
   *
   * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
   * or visit www.oracle.com if you need additional information or have any
   * questions.
   */
  
  package openjdk.tools.jdeprscan.scan;
  
  import openjdk.tools.classfile.ClassFile;
  import openjdk.tools.classfile.ConstantPoolException;
  
  import java.io.IOException;
  import java.net.URI;
  import java.nio.file.FileSystem;
  import java.nio.file.FileSystems;
  import java.nio.file.Files;
  import java.nio.file.NoSuchFileException;
  import java.nio.file.Path;
  import java.nio.file.Paths;
  import java.util.ArrayList;
  import java.util.List;
  import java.util.Optional;
  import java.util.jar.JarEntry;
  import java.util.jar.JarFile;
  import java.util.stream.Stream;
  
  /**
   * A simple search path for classes.
   */
  public class ClassFinder {
      final List<PathEntry> list = new ArrayList<>();
      final boolean verbose;
  
      public ClassFinder(boolean verbose) {
          this.verbose = verbose;
      }
  
      /**
       * Adds a directory to this finder's search path, ignoring errors.
       *
       * @param dirName the directory to add
       */
      public void addDir(String dirName) {
          Path dir = Paths.get(dirName);
  
          if (Files.isDirectory(dir)) {
              list.add(new DirPathEntry(dir));
          }
      }
  
      /**
       * Adds a jar file to this finder's search path, ignoring errors.
       *
       * @param jarName the jar file name to add
       */
      public void addJar(String jarName) {
          try {
              list.add(new JarPathEntry(new JarFile(jarName)));
          } catch (IOException ignore) { }
      }
  
      /**
       * Adds the JRT filesystem to this finder's search path.
       */
      public void addJrt() {
          list.add(new JrtPathEntry());
      }
  
      /**
       * Searches the class path for a class with the given name,
       * returning a ClassFile for it. Returns null if not found.
       *
       * @param className the class to search for
       * @return a ClassFile instance, or null if not found
       */
      public ClassFile find(String className) {
          for (PathEntry pe : list) {
              ClassFile cf = pe.find(className);
              if (cf != null) {
                  return cf;
              }
          }
          return null;
      }
  
      /**
       * An entry in this finder's class path.
       */
      interface PathEntry {
          /**
           * Returns a ClassFile instance corresponding to this name,
           * or null if it's not present in this entry.
           *
           * @param className the class to search for
           * @return a ClassFile instance, or null if not found
           */
          ClassFile find(String className);
      }
  
      /**
       * An entry that represents a jar file.
       */
      class JarPathEntry implements PathEntry {
          final JarFile jarFile;
  
          JarPathEntry(JarFile jf) {
              jarFile = jf;
          }
  
          @Override
          public ClassFile find(String className) {
              JarEntry entry = jarFile.getJarEntry(className + ".class");
              if (entry == null) {
                  return null;
              }
              try {
                  return ClassFile.read(jarFile.getInputStream(entry));
              } catch (IOException | ConstantPoolException ex) {
                  if (verbose) {
                      ex.printStackTrace();
                  }
              }
              return null;
          }
      }
  
      /**
       * An entry that represents a directory containing a class hierarchy.
       */
      class DirPathEntry implements PathEntry {
          final Path dir;
  
          DirPathEntry(Path dir) {
              this.dir = dir;
          }
  
          @Override
          public ClassFile find(String className) {
              Path classFileName = dir.resolve(className + ".class");
              try {
                  return ClassFile.read(classFileName);
              } catch (NoSuchFileException nsfe) {
                  // not found, return silently
              } catch (IOException | ConstantPoolException ex) {
                  if (verbose) {
                      ex.printStackTrace();
                  }
              }
              return null;
          }
      }
  
      /**
       * An entry that represents the JRT filesystem in the running image.
       *
       * JRT filesystem structure is:
       *     /packages/<dotted-pkgname>/<modlink>
       * where modlink is a symbolic link to /modules/<modname> which is
       * the top of the usual package-class hierarchy
       */
      class JrtPathEntry implements PathEntry {
          final FileSystem fs = FileSystems.getFileSystem(URI.create("jrt:/"));
  
          @Override
          public ClassFile find(String className) {
              int end = className.lastIndexOf('/');
              if (end < 0) {
                  return null;
              }
              String pkg = "/packages/" + className.substring(0, end)
                                                   .replace('/', '.');
              try (Stream<Path> mods = Files.list(fs.getPath(pkg))) {
                  Optional<Path> opath =
                      mods.map(path -> path.resolve(className + ".class"))
                          .filter(Files::exists)
                          .findFirst();
                  if (opath.isPresent()) {
                      return ClassFile.read(opath.get());
                  } else {
                      return null;
                  }
              } catch (NoSuchFileException nsfe) {
                  // not found, return silently
              } catch (IOException | ConstantPoolException ex) {
                  if (verbose) {
                      ex.printStackTrace();
                  }
              }
              return null;
          }
      }
  }
  