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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * 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.
 *
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package jdk.internal.jrtfs;

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.nio.ByteBuffer;
import java.nio.channels.Channels;
import java.nio.channels.FileChannel;
import java.nio.channels.NonWritableChannelException;
import java.nio.channels.ReadableByteChannel;
import java.nio.channels.SeekableByteChannel;
import java.nio.file.ClosedFileSystemException;
import java.nio.file.CopyOption;
import java.nio.file.DirectoryStream;
import java.nio.file.FileStore;
import java.nio.file.FileSystem;
import java.nio.file.FileSystemException;
import java.nio.file.InvalidPathException;
import java.nio.file.LinkOption;
import java.nio.file.NoSuchFileException;
import java.nio.file.NotDirectoryException;
import java.nio.file.OpenOption;
import java.nio.file.Path;
import java.nio.file.PathMatcher;
import java.nio.file.ReadOnlyFileSystemException;
import java.nio.file.StandardOpenOption;
import java.nio.file.WatchService;
import java.nio.file.attribute.FileAttribute;
import java.nio.file.attribute.FileTime;
import java.nio.file.attribute.UserPrincipalLookupService;
import java.nio.file.spi.FileSystemProvider;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Map;
import java.util.Objects;
import java.util.Set;
import java.util.regex.Pattern;
import jdk.internal.jimage.ImageReader.Node;
import static java.util.stream.Collectors.toList;

jrt file system implementation built on System jimage files.
Implementation Note: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.
/** * jrt file system implementation built on System jimage files. * * @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. */
class JrtFileSystem extends FileSystem { private final JrtFileSystemProvider provider; private final JrtPath rootPath = new JrtPath(this, "/"); private volatile boolean isOpen; private volatile boolean isClosable; private SystemImage image; JrtFileSystem(JrtFileSystemProvider provider, Map<String, ?> env) throws IOException { this.provider = provider; this.image = SystemImage.open(); // open image file this.isOpen = true; this.isClosable = env != null; } // FileSystem method implementations @Override public boolean isOpen() { return isOpen; } @Override public void close() throws IOException { if (!isClosable) throw new UnsupportedOperationException(); cleanup(); } @Override @SuppressWarnings("deprecation") protected void finalize() throws Throwable { try { cleanup(); } catch (IOException ignored) {} } @Override public FileSystemProvider provider() { return provider; } @Override public Iterable<Path> getRootDirectories() { return Collections.singleton(getRootPath()); } @Override public JrtPath getPath(String first, String... more) { if (more.length == 0) { return new JrtPath(this, first); } StringBuilder sb = new StringBuilder(); sb.append(first); for (String path : more) { if (path.length() > 0) { if (sb.length() > 0) { sb.append('/'); } sb.append(path); } } return new JrtPath(this, sb.toString()); } @Override public final boolean isReadOnly() { return true; } @Override public final UserPrincipalLookupService getUserPrincipalLookupService() { throw new UnsupportedOperationException(); } @Override public final WatchService newWatchService() { throw new UnsupportedOperationException(); } @Override public final Iterable<FileStore> getFileStores() { return Collections.singleton(getFileStore(getRootPath())); } private static final Set<String> supportedFileAttributeViews = Collections.unmodifiableSet( new HashSet<String>(Arrays.asList("basic", "jrt"))); @Override public final Set<String> supportedFileAttributeViews() { return supportedFileAttributeViews; } @Override public final String toString() { return "jrt:/"; } @Override public final String getSeparator() { return "/"; } @Override public PathMatcher getPathMatcher(String syntaxAndInput) { int pos = syntaxAndInput.indexOf(':'); if (pos <= 0 || pos == syntaxAndInput.length()) { throw new IllegalArgumentException("pos is " + pos); } String syntax = syntaxAndInput.substring(0, pos); String input = syntaxAndInput.substring(pos + 1); String expr; if (syntax.equalsIgnoreCase("glob")) { expr = JrtUtils.toRegexPattern(input); } else if (syntax.equalsIgnoreCase("regex")) { expr = input; } else { throw new UnsupportedOperationException("Syntax '" + syntax + "' not recognized"); } // return matcher final Pattern pattern = Pattern.compile(expr); return (Path path) -> pattern.matcher(path.toString()).matches(); } JrtPath resolveLink(JrtPath path) throws IOException { Node node = checkNode(path); if (node.isLink()) { node = node.resolveLink(); return new JrtPath(this, node.getName()); // TBD, normalized? } return path; } JrtFileAttributes getFileAttributes(JrtPath path, LinkOption... options) throws IOException { Node node = checkNode(path); if (node.isLink() && followLinks(options)) { return new JrtFileAttributes(node.resolveLink(true)); } return new JrtFileAttributes(node); }
returns the list of child paths of the given directory "path"
Params:
  • path – name of the directory whose content is listed
Returns:iterator for child paths of the given directory path
/** * returns the list of child paths of the given directory "path" * * @param path name of the directory whose content is listed * @return iterator for child paths of the given directory path */
Iterator<Path> iteratorOf(JrtPath path, DirectoryStream.Filter<? super Path> filter) throws IOException { Node node = checkNode(path).resolveLink(true); if (!node.isDirectory()) { throw new NotDirectoryException(path.getName()); } if (filter == null) { return node.getChildren() .stream() .map(child -> (Path)(path.resolve(new JrtPath(this, child.getNameString()).getFileName()))) .iterator(); } return node.getChildren() .stream() .map(child -> (Path)(path.resolve(new JrtPath(this, child.getNameString()).getFileName()))) .filter(p -> { try { return filter.accept(p); } catch (IOException x) {} return false; }) .iterator(); } // returns the content of the file resource specified by the path byte[] getFileContent(JrtPath path) throws IOException { Node node = checkNode(path); if (node.isDirectory()) { throw new FileSystemException(path + " is a directory"); } //assert node.isResource() : "resource node expected here"; return image.getResource(node); } /////////////// Implementation details below this point ////////// // static utility methods static ReadOnlyFileSystemException readOnly() { return new ReadOnlyFileSystemException(); } // do the supplied options imply that we have to chase symlinks? static boolean followLinks(LinkOption... options) { if (options != null) { for (LinkOption lo : options) { Objects.requireNonNull(lo); if (lo == LinkOption.NOFOLLOW_LINKS) { return false; } else { throw new AssertionError("should not reach here"); } } } return true; } // check that the options passed are supported by (read-only) jrt file system static void checkOptions(Set<? extends OpenOption> options) { // check for options of null type and option is an intance of StandardOpenOption for (OpenOption option : options) { Objects.requireNonNull(option); if (!(option instanceof StandardOpenOption)) { throw new IllegalArgumentException( "option class: " + option.getClass()); } } if (options.contains(StandardOpenOption.WRITE) || options.contains(StandardOpenOption.APPEND)) { throw readOnly(); } } // clean up this file system - called from finalize and close synchronized void cleanup() throws IOException { if (isOpen) { isOpen = false; image.close(); image = null; } } // These methods throw read only file system exception final void setTimes(JrtPath jrtPath, FileTime mtime, FileTime atime, FileTime ctime) throws IOException { throw readOnly(); } // These methods throw read only file system exception final void createDirectory(JrtPath jrtPath, FileAttribute<?>... attrs) throws IOException { throw readOnly(); } final void deleteFile(JrtPath jrtPath, boolean failIfNotExists) throws IOException { throw readOnly(); } final OutputStream newOutputStream(JrtPath jrtPath, OpenOption... options) throws IOException { throw readOnly(); } final void copyFile(boolean deletesrc, JrtPath srcPath, JrtPath dstPath, CopyOption... options) throws IOException { throw readOnly(); } final FileChannel newFileChannel(JrtPath path, Set<? extends OpenOption> options, FileAttribute<?>... attrs) throws IOException { throw new UnsupportedOperationException("newFileChannel"); } final InputStream newInputStream(JrtPath path) throws IOException { return new ByteArrayInputStream(getFileContent(path)); } final SeekableByteChannel newByteChannel(JrtPath path, Set<? extends OpenOption> options, FileAttribute<?>... attrs) throws IOException { checkOptions(options); byte[] buf = getFileContent(path); final ReadableByteChannel rbc = Channels.newChannel(new ByteArrayInputStream(buf)); final long size = buf.length; return new SeekableByteChannel() { long read = 0; @Override public boolean isOpen() { return rbc.isOpen(); } @Override public long position() throws IOException { return read; } @Override public SeekableByteChannel position(long pos) throws IOException { throw new UnsupportedOperationException(); } @Override public int read(ByteBuffer dst) throws IOException { int n = rbc.read(dst); if (n > 0) { read += n; } return n; } @Override public SeekableByteChannel truncate(long size) throws IOException { throw new NonWritableChannelException(); } @Override public int write(ByteBuffer src) throws IOException { throw new NonWritableChannelException(); } @Override public long size() throws IOException { return size; } @Override public void close() throws IOException { rbc.close(); } }; } final JrtFileStore getFileStore(JrtPath path) { return new JrtFileStore(path); } final void ensureOpen() throws IOException { if (!isOpen()) { throw new ClosedFileSystemException(); } } final JrtPath getRootPath() { return rootPath; } boolean isSameFile(JrtPath path1, JrtPath path2) throws IOException { return checkNode(path1) == checkNode(path2); } boolean isLink(JrtPath path) throws IOException { return checkNode(path).isLink(); } boolean exists(JrtPath path) throws IOException { try { checkNode(path); } catch (NoSuchFileException exp) { return false; } return true; } boolean isDirectory(JrtPath path, boolean resolveLinks) throws IOException { Node node = checkNode(path); return resolveLinks && node.isLink() ? node.resolveLink(true).isDirectory() : node.isDirectory(); } JrtPath toRealPath(JrtPath path, LinkOption... options) throws IOException { Node node = checkNode(path); if (followLinks(options) && node.isLink()) { node = node.resolveLink(); } // image node holds the real/absolute path name return new JrtPath(this, node.getName(), true); } private Node lookup(String path) { try { return image.findNode(path); } catch (RuntimeException | IOException ex) { throw new InvalidPathException(path, ex.toString()); } } private Node lookupSymbolic(String path) { int i = 1; while (i < path.length()) { i = path.indexOf('/', i); if (i == -1) { break; } String prefix = path.substring(0, i); Node node = lookup(prefix); if (node == null) { break; } if (node.isLink()) { Node link = node.resolveLink(true); // resolved symbolic path concatenated to the rest of the path String resPath = link.getName() + path.substring(i); node = lookup(resPath); return node != null ? node : lookupSymbolic(resPath); } i++; } return null; } Node checkNode(JrtPath path) throws IOException { ensureOpen(); String p = path.getResolvedPath(); Node node = lookup(p); if (node == null) { node = lookupSymbolic(p); if (node == null) { throw new NoSuchFileException(p); } } return node; } }