content: /*
   * Copyright (c) 2022, 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
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   * questions.
   */
  
  package javac.internal.jrtfs;
  
  import java.io.*;
  import java.net.MalformedURLException;
  import java.net.URL;
  import java.net.URLClassLoader;
  import java.nio.channels.*;
  import java.nio.file.*;
  import java.nio.file.DirectoryStream.Filter;
  import java.nio.file.attribute.*;
  import java.nio.file.spi.FileSystemProvider;
  import java.net.URI;
  import java.security.AccessController;
  import java.security.PrivilegedAction;
  import java.util.HashMap;
  import java.util.Map;
  import java.util.Objects;
  import java.util.Set;
  import java.util.concurrent.ExecutorService;
  
  /**
   * File system provider for jrt file systems. Conditionally creates jrt fs on
   * .jimage file or exploded modules directory of underlying JDK.
   *
   * @implNote This class needs to maintain JDK 8 source compatibility.
   *
   * It is used internally in the JDK to implement jimage/jrtfs access,
   * but also compiled and delivered as part of the jrtfs.jar to support access
   * to the jimage file provided by the shipped JDK by tools running on JDK 8.
   */
  public final class JrtFileSystemProvider extends FileSystemProvider {
  
      private volatile FileSystem theFileSystem;
  
      public JrtFileSystemProvider() {
      }
  
      @Override
      public String getScheme() {
          return "jrt";
      }
  
      /**
       * Need RuntimePermission "accessSystemModules" to create or get jrt:/
       */
      private void checkPermission() {
          @SuppressWarnings("removal")
          SecurityManager sm = System.getSecurityManager();
          if (sm != null) {
              RuntimePermission perm = new RuntimePermission("accessSystemModules");
              sm.checkPermission(perm);
          }
      }
  
      private void checkUri(URI uri) {
          if (!uri.getScheme().equalsIgnoreCase(getScheme())) {
              throw new IllegalArgumentException("URI does not match this provider");
          }
          if (uri.getAuthority() != null) {
              throw new IllegalArgumentException("Authority component present");
          }
          if (uri.getPath() == null) {
              throw new IllegalArgumentException("Path component is undefined");
          }
          if (!uri.getPath().equals("/")) {
              throw new IllegalArgumentException("Path component should be '/'");
          }
          if (uri.getQuery() != null) {
              throw new IllegalArgumentException("Query component present");
          }
          if (uri.getFragment() != null) {
              throw new IllegalArgumentException("Fragment component present");
          }
      }
  
      @Override
      public FileSystem newFileSystem(URI uri, Map<String, ?> env)
              throws IOException {
          Objects.requireNonNull(env);
          checkPermission();
          checkUri(uri);
  
          // ANDROIDIDE-CHANGED: Do not check for java.home property and directly return new file system instance.
          return new JrtFileSystem(this, env);
      }
  
      private static final String JRT_FS_JAR = "jrt-fs.jar";
      private FileSystem newFileSystem(String targetHome, URI uri, Map<String, ?> env)
              throws IOException {
          Objects.requireNonNull(targetHome);
          Path jrtfs = FileSystems.getDefault().getPath(targetHome, "lib", JRT_FS_JAR);
          if (Files.notExists(jrtfs)) {
              throw new IOException(jrtfs.toString() + " not exist");
          }
          Map<String,?> newEnv = new HashMap<>(env);
          newEnv.remove("java.home");
          ClassLoader cl = newJrtFsLoader(jrtfs);
          try {
              Class<?> c = Class.forName(JrtFileSystemProvider.class.getName(), false, cl);
              @SuppressWarnings("deprecation")
              Object tmp = c.newInstance();
              return ((FileSystemProvider)tmp).newFileSystem(uri, newEnv);
          } catch (ClassNotFoundException |
                   IllegalAccessException |
                   InstantiationException e) {
              throw new IOException(e);
          }
      }
  
      private static class JrtFsLoader extends URLClassLoader {
          JrtFsLoader(URL[] urls) {
              super(urls);
          }
          @Override
          protected Class<?> loadClass(String cn, boolean resolve)
                  throws ClassNotFoundException
          {
              Class<?> c = findLoadedClass(cn);
              if (c == null) {
                  URL u = findResource(cn.replace('.', '/') + ".class");
                  if (u != null) {
                      c = findClass(cn);
                  } else {
                      return super.loadClass(cn, resolve);
                  }
              }
              if (resolve)
                  resolveClass(c);
              return c;
          }
      }
  
      @SuppressWarnings("removal")
      private static URLClassLoader newJrtFsLoader(Path jrtfs) {
          final URL url;
          try {
              url = jrtfs.toUri().toURL();
          } catch (MalformedURLException mue) {
              throw new IllegalArgumentException(mue);
          }
  
          final URL[] urls = new URL[] { url };
          return AccessController.doPrivileged(
                  new PrivilegedAction<URLClassLoader>() {
                      @Override
                      public URLClassLoader run() {
                          return new JrtFsLoader(urls);
                      }
                  }
          );
      }
  
      @Override
      public Path getPath(URI uri) {
          checkPermission();
          if (!uri.getScheme().equalsIgnoreCase(getScheme())) {
              throw new IllegalArgumentException("URI does not match this provider");
          }
          if (uri.getAuthority() != null) {
              throw new IllegalArgumentException("Authority component present");
          }
          if (uri.getQuery() != null) {
              throw new IllegalArgumentException("Query component present");
          }
          if (uri.getFragment() != null) {
              throw new IllegalArgumentException("Fragment component present");
          }
          String path = uri.getPath();
          if (path == null || path.charAt(0) != '/' || path.contains("..")) {
              throw new IllegalArgumentException("Invalid path component");
          }
  
          return getTheFileSystem().getPath("/modules" + path);
      }
  
      private FileSystem getTheFileSystem() {
          checkPermission();
          FileSystem fs = this.theFileSystem;
          if (fs == null) {
              synchronized (this) {
                  fs = this.theFileSystem;
                  if (fs == null) {
                      try {
                          this.theFileSystem = fs = new JrtFileSystem(this, null);
                      } catch (IOException ioe) {
                          throw new InternalError(ioe);
                      }
                  }
              }
          }
          return fs;
      }
  
      @Override
      public FileSystem getFileSystem(URI uri) {
          checkPermission();
          checkUri(uri);
          return getTheFileSystem();
      }
  
      // Checks that the given file is a JrtPath
      static final JrtPath toJrtPath(Path path) {
          Objects.requireNonNull(path, "path");
          if (!(path instanceof JrtPath)) {
              throw new ProviderMismatchException();
          }
          return (JrtPath) path;
      }
  
      @Override
      public void checkAccess(Path path, AccessMode... modes) throws IOException {
          toJrtPath(path).checkAccess(modes);
      }
  
      @Override
      public Path readSymbolicLink(Path link) throws IOException {
          return toJrtPath(link).readSymbolicLink();
      }
  
      @Override
      public void copy(Path src, Path target, CopyOption... options)
              throws IOException {
          toJrtPath(src).copy(toJrtPath(target), options);
      }
  
      @Override
      public void createDirectory(Path path, FileAttribute<?>... attrs)
              throws IOException {
          toJrtPath(path).createDirectory(attrs);
      }
  
      @Override
      public final void delete(Path path) throws IOException {
          toJrtPath(path).delete();
      }
  
      @Override
      @SuppressWarnings("unchecked")
      public <V extends FileAttributeView> V
              getFileAttributeView(Path path, Class<V> type, LinkOption... options) {
          return JrtFileAttributeView.get(toJrtPath(path), type, options);
      }
  
      @Override
      public FileStore getFileStore(Path path) throws IOException {
          return toJrtPath(path).getFileStore();
      }
  
      @Override
      public boolean isHidden(Path path) {
          return toJrtPath(path).isHidden();
      }
  
      @Override
      public boolean isSameFile(Path path, Path other) throws IOException {
          return toJrtPath(path).isSameFile(other);
      }
  
      @Override
      public void move(Path src, Path target, CopyOption... options)
              throws IOException {
          toJrtPath(src).move(toJrtPath(target), options);
      }
  
      @Override
      public AsynchronousFileChannel newAsynchronousFileChannel(Path path,
              Set<? extends OpenOption> options,
              ExecutorService exec,
              FileAttribute<?>... attrs)
              throws IOException {
          throw new UnsupportedOperationException();
      }
  
      @Override
      public SeekableByteChannel newByteChannel(Path path,
              Set<? extends OpenOption> options,
              FileAttribute<?>... attrs)
              throws IOException {
          return toJrtPath(path).newByteChannel(options, attrs);
      }
  
      @Override
      public DirectoryStream<Path> newDirectoryStream(
              Path path, Filter<? super Path> filter) throws IOException {
          return toJrtPath(path).newDirectoryStream(filter);
      }
  
      @Override
      public FileChannel newFileChannel(Path path,
              Set<? extends OpenOption> options,
              FileAttribute<?>... attrs)
              throws IOException {
          return toJrtPath(path).newFileChannel(options, attrs);
      }
  
      @Override
      public InputStream newInputStream(Path path, OpenOption... options)
              throws IOException {
          return toJrtPath(path).newInputStream(options);
      }
  
      @Override
      public OutputStream newOutputStream(Path path, OpenOption... options)
              throws IOException {
          return toJrtPath(path).newOutputStream(options);
      }
  
      @Override
      @SuppressWarnings("unchecked") // Cast to A
      public <A extends BasicFileAttributes> A
              readAttributes(Path path, Class<A> type, LinkOption... options)
              throws IOException {
          if (type == BasicFileAttributes.class || type == JrtFileAttributes.class) {
              return (A) toJrtPath(path).getAttributes(options);
          }
          return null;
      }
  
      @Override
      public Map<String, Object>
              readAttributes(Path path, String attribute, LinkOption... options)
              throws IOException {
          return toJrtPath(path).readAttributes(attribute, options);
      }
  
      @Override
      public void setAttribute(Path path, String attribute,
              Object value, LinkOption... options)
              throws IOException {
          toJrtPath(path).setAttribute(attribute, value, options);
      }
  }