jdk/src/java.base/share/classes/jdk/internal/jimage/ImageReader.java - platform/libcore - Git at Google

 /*
  * Copyright (c) 2014, 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 jdk.internal.jimage;

 import java.io.IOException;
 import java.io.UncheckedIOException;
 import java.nio.ByteBuffer;
 import java.nio.ByteOrder;
 import java.nio.IntBuffer;
 import java.nio.file.Files;
 import java.nio.file.attribute.BasicFileAttributes;
 import java.nio.file.attribute.FileTime;
 import java.nio.file.Paths;
 import java.nio.file.Path;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.function.Consumer;
 import static jdk.internal.jimage.UTF8String.*;

 public class ImageReader extends BasicImageReader {
     // well-known strings needed for image file system.
     static final UTF8String ROOT_STRING = UTF8String.SLASH_STRING;

     // attributes of the .jimage file. jimage file does not contain
     // attributes for the individual resources (yet). We use attributes
     // of the jimage file itself (creation, modification, access times).
     // Iniitalized lazily, see {@link #imageFileAttributes()}.
     private BasicFileAttributes imageFileAttributes;

     private final ImageModuleData moduleData;

     // directory management implementation
     private final Map<UTF8String, Node> nodes;
     private volatile Directory rootDir;

     private Directory packagesDir;
     private Directory modulesDir;

     ImageReader(String imagePath, ByteOrder byteOrder) throws IOException {
         super(imagePath, byteOrder);
         this.moduleData = new ImageModuleData(this);
         this.nodes = Collections.synchronizedMap(new HashMap<>());
     }

     ImageReader(String imagePath) throws IOException {
         this(imagePath, ByteOrder.nativeOrder());
     }

     public static ImageReader open(String imagePath, ByteOrder byteOrder) throws IOException {
         return new ImageReader(imagePath, byteOrder);
     }

     /**
      * Opens the given file path as an image file, returning an {@code ImageReader}.
      */
     public static ImageReader open(String imagePath) throws IOException {
         return open(imagePath, ByteOrder.nativeOrder());
     }

     @Override
     public synchronized void close() throws IOException {
         super.close();
         clearNodes();
     }

     @Override
     public ImageLocation findLocation(UTF8String name) {
         ImageLocation location = super.findLocation(name);

         // NOTE: This should be removed when module system is up in full.
         if (location == null) {
             int index = name.lastIndexOf('/');

             if (index != -1) {
                 UTF8String packageName = name.substring(0, index);
                 UTF8String moduleName = moduleData.packageToModule(packageName);

                 if (moduleName != null) {
                     UTF8String fullName = UTF8String.SLASH_STRING.concat(moduleName,
                             UTF8String.SLASH_STRING, name);
                     location = super.findLocation(fullName);
                 }
             } else {
                 // No package, try all modules.
                 for (String mod : moduleData.allModuleNames()) {
                     location = super.findLocation("/" + mod + "/" + name);
                     if (location != null) {
                         break;
                     }
                 }
             }
         }

         return location;
     }

     /**
      * Return the module name that contains the given package name.
      */
     public String getModule(String packageName) {
         return moduleData.packageToModule(packageName);
     }

     // jimage file does not store directory structure. We build nodes
     // using the "path" strings found in the jimage file.
     // Node can be a directory or a resource
     public abstract static class Node {
         private static final int ROOT_DIR = 0b0000_0000_0000_0001;
         private static final int PACKAGES_DIR = 0b0000_0000_0000_0010;
         private static final int MODULES_DIR = 0b0000_0000_0000_0100;

         private int flags;
         private final UTF8String name;
         private final BasicFileAttributes fileAttrs;
         private boolean completed;

         Node(UTF8String name, BasicFileAttributes fileAttrs) {
             assert name != null;
             assert fileAttrs != null;
             this.name = name;
             this.fileAttrs = fileAttrs;
         }

         /**
          * A node is completed when all its direct children have been built.
          *
          * @return
          */
         public boolean isCompleted() {
             return completed;
         }

         public void setCompleted(boolean completed) {
             this.completed = completed;
         }

         public final void setIsRootDir() {
             flags |= ROOT_DIR;
         }

         public final boolean isRootDir() {
             return (flags & ROOT_DIR) != 0;
         }

         public final void setIsPackagesDir() {
             flags |= PACKAGES_DIR;
         }

         public final boolean isPackagesDir() {
             return (flags & PACKAGES_DIR) != 0;
         }

         public final void setIsModulesDir() {
             flags |= MODULES_DIR;
         }

         public final boolean isModulesDir() {
             return (flags & MODULES_DIR) != 0;
         }

         public final UTF8String getName() {
             return name;
         }

         public final BasicFileAttributes getFileAttributes() {
             return fileAttrs;
         }

         // resolve this Node (if this is a soft link, get underlying Node)
         public final Node resolveLink() {
             return resolveLink(false);
         }

         public Node resolveLink(boolean recursive) {
             return this;
         }

         // is this a soft link Node?
         public boolean isLink() {
             return false;
         }

         public boolean isDirectory() {
             return false;
         }

         public List<Node> getChildren() {
             throw new IllegalArgumentException("not a directory: " + getNameString());
         }

         public boolean isResource() {
             return false;
         }

         public ImageLocation getLocation() {
             throw new IllegalArgumentException("not a resource: " + getNameString());
         }

         public long size() {
             return 0L;
         }

         public long compressedSize() {
             return 0L;
         }

         public String extension() {
             return null;
         }

         public long contentOffset() {
             return 0L;
         }

         public final FileTime creationTime() {
             return fileAttrs.creationTime();
         }

         public final FileTime lastAccessTime() {
             return fileAttrs.lastAccessTime();
         }

         public final FileTime lastModifiedTime() {
             return fileAttrs.lastModifiedTime();
         }

         public final String getNameString() {
             return name.toString();
         }

         @Override
         public final String toString() {
             return getNameString();
         }

         @Override
         public final int hashCode() {
             return name.hashCode();
         }

         @Override
         public final boolean equals(Object other) {
             if (this == other) {
                 return true;
             }

             if (other instanceof Node) {
                 return name.equals(((Node) other).name);
             }

             return false;
         }
     }

     // directory node - directory has full path name without '/' at end.
     static final class Directory extends Node {
         private final List<Node> children;

         private Directory(Directory parent, UTF8String name, BasicFileAttributes fileAttrs) {
             super(name, fileAttrs);
             children = new ArrayList<>();
         }

         static Directory create(Directory parent, UTF8String name, BasicFileAttributes fileAttrs) {
             Directory dir = new Directory(parent, name, fileAttrs);
             if (parent != null) {
                 parent.addChild(dir);
             }
             return dir;
         }

         @Override
         public boolean isDirectory() {
             return true;
         }

         @Override
         public List<Node> getChildren() {
             return Collections.unmodifiableList(children);
         }

         void addChild(Node node) {
             children.add(node);
         }

         public void walk(Consumer<? super Node> consumer) {
             consumer.accept(this);
             for ( Node child : children ) {
                 if (child.isDirectory()) {
                     ((Directory)child).walk(consumer);
                 } else {
                     consumer.accept(child);
                 }
             }
         }
     }

     // "resource" is .class or any other resource (compressed/uncompressed) in a jimage.
     // full path of the resource is the "name" of the resource.
     static class Resource extends Node {
         private final ImageLocation loc;

         private Resource(Directory parent, ImageLocation loc, BasicFileAttributes fileAttrs) {
             this(parent, loc.getFullName(true), loc, fileAttrs);
         }

         private Resource(Directory parent, UTF8String name, ImageLocation loc, BasicFileAttributes fileAttrs) {
             super(name, fileAttrs);
             this.loc = loc;
          }

         static Resource create(Directory parent, ImageLocation loc, BasicFileAttributes fileAttrs) {
             Resource resource = new Resource(parent, loc, fileAttrs);
             parent.addChild(resource);
             return resource;
         }

         static Resource create(Directory parent, UTF8String name, ImageLocation loc, BasicFileAttributes fileAttrs) {
             Resource resource = new Resource(parent, name, loc, fileAttrs);
             parent.addChild(resource);
             return resource;
         }

         @Override
         public boolean isCompleted() {
             return true;
         }

         @Override
         public boolean isResource() {
             return true;
         }

         @Override
         public ImageLocation getLocation() {
             return loc;
         }

         @Override
         public long size() {
             return loc.getUncompressedSize();
         }

         @Override
         public long compressedSize() {
             return loc.getCompressedSize();
         }

         @Override
         public String extension() {
             return loc.getExtensionString();
         }

         @Override
         public long contentOffset() {
             return loc.getContentOffset();
         }
     }

     // represents a soft link to another Node
     static class LinkNode extends Node {
         private final Node link;

         private LinkNode(Directory parent, UTF8String name, Node link) {
             super(name, link.getFileAttributes());
             this.link = link;
         }

         static LinkNode create(Directory parent, UTF8String name, Node link) {
             LinkNode linkNode = new LinkNode(parent, name, link);
             parent.addChild(linkNode);
             return linkNode;
         }

         @Override
         public boolean isCompleted() {
             return true;
         }

         @Override
         public Node resolveLink(boolean recursive) {
             return recursive && (link instanceof LinkNode)? ((LinkNode)link).resolveLink(true) : link;
         }

         @Override
         public boolean isLink() {
             return true;
         }
     }

     // directory management interface
     public Directory getRootDirectory() {
         return buildRootDirectory();
     }

     public Node findNode(String name) {
         return findNode(new UTF8String(name));
     }

     public Node findNode(byte[] name) {
         return findNode(new UTF8String(name));
     }

     /**
      * To visit sub tree resources.
      */
     interface LocationVisitor {

         void visit(ImageLocation loc);
     }

     /**
      * Lazily build a node from a name.
      */
     private final class NodeBuilder {

         private static final int SIZE_OF_OFFSET = 4;

         private final UTF8String name;

         private NodeBuilder(UTF8String name) {
             this.name = name;
         }

         private Node buildNode() {
             Node n = null;
             boolean isPackages = false;
             boolean isModules = false;
             String strName = name.toString();
             if (strName.startsWith("" + PACKAGES_STRING)) {
                 isPackages = true;
             } else {
                 if (strName.startsWith("" + MODULES_STRING)) {
                     isModules = true;
                 }
             }
             if (!isModules && !isPackages) {
                 return null;
             }

             ImageLocation loc = findLocation(name);

             if (loc != null) { // A sub tree node
                 if (isPackages) {
                     n = handlePackages(strName, loc);
                 } else { // modules sub tree
                     n = handleModulesSubTree(strName, loc);
                 }
             } else { // Asking for a resource? /modules/java.base/java/lang/Object.class
                 if (isModules) {
                     n = handleResource(strName, loc);
                 }
             }
             return n;
         }

         private void visitLocation(ImageLocation loc, LocationVisitor visitor) {
             byte[] offsets = getResource(loc);
             ByteBuffer buffer = ByteBuffer.wrap(offsets);
             buffer.order(getByteOrder());
             IntBuffer intBuffer = buffer.asIntBuffer();
             for (int i = 0; i < offsets.length / SIZE_OF_OFFSET; i++) {
                 int offset = intBuffer.get(i);
                 ImageLocation pkgLoc = getLocation(offset);
                 visitor.visit(pkgLoc);
             }
         }

         private Node handlePackages(String name, ImageLocation loc) {
             long size = loc.getUncompressedSize();
             Node n = null;
             // Only possiblities are /packages, /packages/package/module
             if (name.equals("" + PACKAGES_STRING)) {
                 visitLocation(loc, (childloc) -> {
                     findNode(childloc.getFullName());
                 });
                 packagesDir.setCompleted(true);
                 n = packagesDir;
             } else {
                 if (size != 0) { // children are links to module
                     String pkgName = getBaseExt(loc);
                     Directory pkgDir = newDirectory(packagesDir,
                             packagesDir.getName().concat(SLASH_STRING, new UTF8String(pkgName)));
                     visitLocation(loc, (childloc) -> {
                         findNode(childloc.getFullName());
                     });
                     pkgDir.setCompleted(true);
                     n = pkgDir;
                 } else { // Link to module
                     String pkgName = loc.getParentString();
                     String modName = getBaseExt(loc);
                     Node targetNode = findNode(MODULES_STRING + "/" + modName);
                     if (targetNode != null) {
                         UTF8String pkgDirName = packagesDir.getName().concat(SLASH_STRING, new UTF8String(pkgName));
                         Directory pkgDir = (Directory) nodes.get(pkgDirName);
                         Node linkNode = newLinkNode(pkgDir,
                                 pkgDir.getName().concat(SLASH_STRING, new UTF8String(modName)), targetNode);
                         n = linkNode;
                     }
                 }
             }
             return n;
         }

         private Node handleModulesSubTree(String name, ImageLocation loc) {
             Node n;
             Directory dir = makeDirectories(loc.getFullName());
             visitLocation(loc, (childloc) -> {
                 String path = childloc.getFullNameString();
                 if (path.startsWith(MODULES_STRING.toString())) { // a package
                     makeDirectories(childloc.getFullName());
                 } else { // a resource
                     makeDirectories(childloc.buildName(true, true, false));
                     newResource(dir, childloc);
                 }
             });
             dir.setCompleted(true);
             n = dir;
             return n;
         }

         private Node handleResource(String name, ImageLocation loc) {
             Node n = null;
             String locationPath = name.substring((MODULES_STRING).length());
             ImageLocation resourceLoc = findLocation(locationPath);
             if (resourceLoc != null) {
                 Directory dir = makeDirectories(resourceLoc.buildName(true, true, false));
                 Resource res = newResource(dir, resourceLoc);
                 n = res;
             }
             return n;
         }

         private String getBaseExt(ImageLocation loc) {
             String base = loc.getBaseString();
             String ext = loc.getExtensionString();
             if (ext != null && !ext.isEmpty()) {
                 base = base + "." + ext;
             }
             return base;
         }
     }

     public synchronized Node findNode(UTF8String name) {
         buildRootDirectory();
         Node n = nodes.get(name);
         if (n == null || !n.isCompleted()) {
             NodeBuilder builder = new NodeBuilder(name);
             n = builder.buildNode();
         }
         return n;
     }

     private synchronized void clearNodes() {
         nodes.clear();
         rootDir = null;
     }

     /**
      * Returns the file attributes of the image file.
      */
     private BasicFileAttributes imageFileAttributes() {
         BasicFileAttributes attrs = imageFileAttributes;
         if (attrs == null) {
             try {
                 Path file = Paths.get(imagePath());
                 attrs = Files.readAttributes(file, BasicFileAttributes.class);
             } catch (IOException ioe) {
                 throw new UncheckedIOException(ioe);
             }
             imageFileAttributes = attrs;
         }
         return attrs;
     }

     private synchronized Directory buildRootDirectory() {
         if (rootDir != null) {
             return rootDir;
         }

         // FIXME no time information per resource in jimage file (yet?)
         // we use file attributes of jimage itself.
         // root directory
         rootDir = newDirectory(null, ROOT_STRING);
         rootDir.setIsRootDir();

         // /packages dir
         packagesDir = newDirectory(rootDir, PACKAGES_STRING);
         packagesDir.setIsPackagesDir();

         // /modules dir
         modulesDir = newDirectory(rootDir, MODULES_STRING);
         modulesDir.setIsModulesDir();

         rootDir.setCompleted(true);
         return rootDir;
     }

     private Directory newDirectory(Directory parent, UTF8String name) {
         Directory dir = Directory.create(parent, name, imageFileAttributes());
         nodes.put(dir.getName(), dir);
         return dir;
     }

     private Resource newResource(Directory parent, ImageLocation loc) {
         Resource res = Resource.create(parent, loc, imageFileAttributes());
         nodes.put(res.getName(), res);
         return res;
     }

     private LinkNode newLinkNode(Directory dir, UTF8String name, Node link) {
         LinkNode linkNode = LinkNode.create(dir, name, link);
         nodes.put(linkNode.getName(), linkNode);
         return linkNode;
     }

     private List<UTF8String> dirs(UTF8String parent) {
         List<UTF8String> splits = new ArrayList<>();

         for (int i = 1; i < parent.length(); i++) {
             if (parent.byteAt(i) == '/') {
                 splits.add(parent.substring(0, i));
             }
         }

         splits.add(parent);

         return splits;
     }

     private Directory makeDirectories(UTF8String parent) {
         Directory last = rootDir;
         List<UTF8String> dirs = dirs(parent);

         for (UTF8String dir : dirs) {
             Directory nextDir = (Directory) nodes.get(dir);
             if (nextDir == null) {
                 nextDir = newDirectory(last, dir);
             }
             last = nextDir;
         }

         return last;
     }

     public byte[] getResource(Node node) throws IOException {
         if (node.isResource()) {
             return super.getResource(node.getLocation());
         }
         throw new IOException("Not a resource: " + node);
     }

     public byte[] getResource(Resource rs) throws IOException {
         return super.getResource(rs.getLocation());
     }
 }
	/*
	* Copyright (c) 2014, 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 jdk.internal.jimage;

	import java.io.IOException;
	import java.io.UncheckedIOException;
	import java.nio.ByteBuffer;
	import java.nio.ByteOrder;
	import java.nio.IntBuffer;
	import java.nio.file.Files;
	import java.nio.file.attribute.BasicFileAttributes;
	import java.nio.file.attribute.FileTime;
	import java.nio.file.Paths;
	import java.nio.file.Path;
	import java.util.ArrayList;
	import java.util.Collections;
	import java.util.HashMap;
	import java.util.List;
	import java.util.Map;
	import java.util.function.Consumer;
	import static jdk.internal.jimage.UTF8String.*;

	public class ImageReader extends BasicImageReader {
	// well-known strings needed for image file system.
	static final UTF8String ROOT_STRING = UTF8String.SLASH_STRING;

	// attributes of the .jimage file. jimage file does not contain
	// attributes for the individual resources (yet). We use attributes
	// of the jimage file itself (creation, modification, access times).
	// Iniitalized lazily, see {@link #imageFileAttributes()}.
	private BasicFileAttributes imageFileAttributes;

	private final ImageModuleData moduleData;

	// directory management implementation
	private final Map<UTF8String, Node> nodes;
	private volatile Directory rootDir;

	private Directory packagesDir;
	private Directory modulesDir;

	ImageReader(String imagePath, ByteOrder byteOrder) throws IOException {
	super(imagePath, byteOrder);
	this.moduleData = new ImageModuleData(this);
	this.nodes = Collections.synchronizedMap(new HashMap<>());
	}

	ImageReader(String imagePath) throws IOException {
	this(imagePath, ByteOrder.nativeOrder());
	}

	public static ImageReader open(String imagePath, ByteOrder byteOrder) throws IOException {
	return new ImageReader(imagePath, byteOrder);
	}

	/**
	* Opens the given file path as an image file, returning an {@code ImageReader}.
	*/
	public static ImageReader open(String imagePath) throws IOException {
	return open(imagePath, ByteOrder.nativeOrder());
	}

	@Override
	public synchronized void close() throws IOException {
	super.close();
	clearNodes();
	}

	@Override
	public ImageLocation findLocation(UTF8String name) {
	ImageLocation location = super.findLocation(name);

	// NOTE: This should be removed when module system is up in full.
	if (location == null) {
	int index = name.lastIndexOf('/');

	if (index != -1) {
	UTF8String packageName = name.substring(0, index);
	UTF8String moduleName = moduleData.packageToModule(packageName);

	if (moduleName != null) {
	UTF8String fullName = UTF8String.SLASH_STRING.concat(moduleName,
	UTF8String.SLASH_STRING, name);
	location = super.findLocation(fullName);
	}
	} else {
	// No package, try all modules.
	for (String mod : moduleData.allModuleNames()) {
	location = super.findLocation("/" + mod + "/" + name);
	if (location != null) {
	break;
	}
	}
	}
	}

	return location;
	}

	/**
	* Return the module name that contains the given package name.
	*/
	public String getModule(String packageName) {
	return moduleData.packageToModule(packageName);
	}

	// jimage file does not store directory structure. We build nodes
	// using the "path" strings found in the jimage file.
	// Node can be a directory or a resource
	public abstract static class Node {
	private static final int ROOT_DIR = 0b0000_0000_0000_0001;
	private static final int PACKAGES_DIR = 0b0000_0000_0000_0010;
	private static final int MODULES_DIR = 0b0000_0000_0000_0100;

	private int flags;
	private final UTF8String name;
	private final BasicFileAttributes fileAttrs;
	private boolean completed;

	Node(UTF8String name, BasicFileAttributes fileAttrs) {
	assert name != null;
	assert fileAttrs != null;
	this.name = name;
	this.fileAttrs = fileAttrs;
	}

	/**
	* A node is completed when all its direct children have been built.
	*
	* @return
	*/
	public boolean isCompleted() {
	return completed;
	}

	public void setCompleted(boolean completed) {
	this.completed = completed;
	}

	public final void setIsRootDir() {
	flags \|= ROOT_DIR;
	}

	public final boolean isRootDir() {
	return (flags & ROOT_DIR) != 0;
	}

	public final void setIsPackagesDir() {
	flags \|= PACKAGES_DIR;
	}

	public final boolean isPackagesDir() {
	return (flags & PACKAGES_DIR) != 0;
	}

	public final void setIsModulesDir() {
	flags \|= MODULES_DIR;
	}

	public final boolean isModulesDir() {
	return (flags & MODULES_DIR) != 0;
	}

	public final UTF8String getName() {
	return name;
	}

	public final BasicFileAttributes getFileAttributes() {
	return fileAttrs;
	}

	// resolve this Node (if this is a soft link, get underlying Node)
	public final Node resolveLink() {
	return resolveLink(false);
	}

	public Node resolveLink(boolean recursive) {
	return this;
	}

	// is this a soft link Node?
	public boolean isLink() {
	return false;
	}

	public boolean isDirectory() {
	return false;
	}

	public List<Node> getChildren() {
	throw new IllegalArgumentException("not a directory: " + getNameString());
	}

	public boolean isResource() {
	return false;
	}

	public ImageLocation getLocation() {
	throw new IllegalArgumentException("not a resource: " + getNameString());
	}

	public long size() {
	return 0L;
	}

	public long compressedSize() {
	return 0L;
	}

	public String extension() {
	return null;
	}

	public long contentOffset() {
	return 0L;
	}

	public final FileTime creationTime() {
	return fileAttrs.creationTime();
	}

	public final FileTime lastAccessTime() {
	return fileAttrs.lastAccessTime();
	}

	public final FileTime lastModifiedTime() {
	return fileAttrs.lastModifiedTime();
	}

	public final String getNameString() {
	return name.toString();
	}

	@Override
	public final String toString() {
	return getNameString();
	}

	@Override
	public final int hashCode() {
	return name.hashCode();
	}

	@Override
	public final boolean equals(Object other) {
	if (this == other) {
	return true;
	}

	if (other instanceof Node) {
	return name.equals(((Node) other).name);
	}

	return false;
	}
	}

	// directory node - directory has full path name without '/' at end.
	static final class Directory extends Node {
	private final List<Node> children;

	private Directory(Directory parent, UTF8String name, BasicFileAttributes fileAttrs) {
	super(name, fileAttrs);
	children = new ArrayList<>();
	}

	static Directory create(Directory parent, UTF8String name, BasicFileAttributes fileAttrs) {
	Directory dir = new Directory(parent, name, fileAttrs);
	if (parent != null) {
	parent.addChild(dir);
	}
	return dir;
	}

	@Override
	public boolean isDirectory() {
	return true;
	}

	@Override
	public List<Node> getChildren() {
	return Collections.unmodifiableList(children);
	}

	void addChild(Node node) {
	children.add(node);
	}

	public void walk(Consumer<? super Node> consumer) {
	consumer.accept(this);
	for ( Node child : children ) {
	if (child.isDirectory()) {
	((Directory)child).walk(consumer);
	} else {
	consumer.accept(child);
	}
	}
	}
	}

	// "resource" is .class or any other resource (compressed/uncompressed) in a jimage.
	// full path of the resource is the "name" of the resource.
	static class Resource extends Node {
	private final ImageLocation loc;

	private Resource(Directory parent, ImageLocation loc, BasicFileAttributes fileAttrs) {
	this(parent, loc.getFullName(true), loc, fileAttrs);
	}

	private Resource(Directory parent, UTF8String name, ImageLocation loc, BasicFileAttributes fileAttrs) {
	super(name, fileAttrs);
	this.loc = loc;
	}

	static Resource create(Directory parent, ImageLocation loc, BasicFileAttributes fileAttrs) {
	Resource resource = new Resource(parent, loc, fileAttrs);
	parent.addChild(resource);
	return resource;
	}

	static Resource create(Directory parent, UTF8String name, ImageLocation loc, BasicFileAttributes fileAttrs) {
	Resource resource = new Resource(parent, name, loc, fileAttrs);
	parent.addChild(resource);
	return resource;
	}

	@Override
	public boolean isCompleted() {
	return true;
	}

	@Override
	public boolean isResource() {
	return true;
	}

	@Override
	public ImageLocation getLocation() {
	return loc;
	}

	@Override
	public long size() {
	return loc.getUncompressedSize();
	}

	@Override
	public long compressedSize() {
	return loc.getCompressedSize();
	}

	@Override
	public String extension() {
	return loc.getExtensionString();
	}

	@Override
	public long contentOffset() {
	return loc.getContentOffset();
	}
	}

	// represents a soft link to another Node
	static class LinkNode extends Node {
	private final Node link;

	private LinkNode(Directory parent, UTF8String name, Node link) {
	super(name, link.getFileAttributes());
	this.link = link;
	}

	static LinkNode create(Directory parent, UTF8String name, Node link) {
	LinkNode linkNode = new LinkNode(parent, name, link);
	parent.addChild(linkNode);
	return linkNode;
	}

	@Override
	public boolean isCompleted() {
	return true;
	}

	@Override
	public Node resolveLink(boolean recursive) {
	return recursive && (link instanceof LinkNode)? ((LinkNode)link).resolveLink(true) : link;
	}

	@Override
	public boolean isLink() {
	return true;
	}
	}

	// directory management interface
	public Directory getRootDirectory() {
	return buildRootDirectory();
	}

	public Node findNode(String name) {
	return findNode(new UTF8String(name));
	}

	public Node findNode(byte[] name) {
	return findNode(new UTF8String(name));
	}

	/**
	* To visit sub tree resources.
	*/
	interface LocationVisitor {

	void visit(ImageLocation loc);
	}

	/**
	* Lazily build a node from a name.
	*/
	private final class NodeBuilder {

	private static final int SIZE_OF_OFFSET = 4;

	private final UTF8String name;

	private NodeBuilder(UTF8String name) {
	this.name = name;
	}

	private Node buildNode() {
	Node n = null;
	boolean isPackages = false;
	boolean isModules = false;
	String strName = name.toString();
	if (strName.startsWith("" + PACKAGES_STRING)) {
	isPackages = true;
	} else {
	if (strName.startsWith("" + MODULES_STRING)) {
	isModules = true;
	}
	}
	if (!isModules && !isPackages) {
	return null;
	}

	ImageLocation loc = findLocation(name);

	if (loc != null) { // A sub tree node
	if (isPackages) {
	n = handlePackages(strName, loc);
	} else { // modules sub tree
	n = handleModulesSubTree(strName, loc);
	}
	} else { // Asking for a resource? /modules/java.base/java/lang/Object.class
	if (isModules) {
	n = handleResource(strName, loc);
	}
	}
	return n;
	}

	private void visitLocation(ImageLocation loc, LocationVisitor visitor) {
	byte[] offsets = getResource(loc);
	ByteBuffer buffer = ByteBuffer.wrap(offsets);
	buffer.order(getByteOrder());
	IntBuffer intBuffer = buffer.asIntBuffer();
	for (int i = 0; i < offsets.length / SIZE_OF_OFFSET; i++) {
	int offset = intBuffer.get(i);
	ImageLocation pkgLoc = getLocation(offset);
	visitor.visit(pkgLoc);
	}
	}

	private Node handlePackages(String name, ImageLocation loc) {
	long size = loc.getUncompressedSize();
	Node n = null;
	// Only possiblities are /packages, /packages/package/module
	if (name.equals("" + PACKAGES_STRING)) {
	visitLocation(loc, (childloc) -> {
	findNode(childloc.getFullName());
	});
	packagesDir.setCompleted(true);
	n = packagesDir;
	} else {
	if (size != 0) { // children are links to module
	String pkgName = getBaseExt(loc);
	Directory pkgDir = newDirectory(packagesDir,
	packagesDir.getName().concat(SLASH_STRING, new UTF8String(pkgName)));
	visitLocation(loc, (childloc) -> {
	findNode(childloc.getFullName());
	});
	pkgDir.setCompleted(true);
	n = pkgDir;
	} else { // Link to module
	String pkgName = loc.getParentString();
	String modName = getBaseExt(loc);
	Node targetNode = findNode(MODULES_STRING + "/" + modName);
	if (targetNode != null) {
	UTF8String pkgDirName = packagesDir.getName().concat(SLASH_STRING, new UTF8String(pkgName));
	Directory pkgDir = (Directory) nodes.get(pkgDirName);
	Node linkNode = newLinkNode(pkgDir,
	pkgDir.getName().concat(SLASH_STRING, new UTF8String(modName)), targetNode);
	n = linkNode;
	}
	}
	}
	return n;
	}

	private Node handleModulesSubTree(String name, ImageLocation loc) {
	Node n;
	Directory dir = makeDirectories(loc.getFullName());
	visitLocation(loc, (childloc) -> {
	String path = childloc.getFullNameString();
	if (path.startsWith(MODULES_STRING.toString())) { // a package
	makeDirectories(childloc.getFullName());
	} else { // a resource
	makeDirectories(childloc.buildName(true, true, false));
	newResource(dir, childloc);
	}
	});
	dir.setCompleted(true);
	n = dir;
	return n;
	}

	private Node handleResource(String name, ImageLocation loc) {
	Node n = null;
	String locationPath = name.substring((MODULES_STRING).length());
	ImageLocation resourceLoc = findLocation(locationPath);
	if (resourceLoc != null) {
	Directory dir = makeDirectories(resourceLoc.buildName(true, true, false));
	Resource res = newResource(dir, resourceLoc);
	n = res;
	}
	return n;
	}

	private String getBaseExt(ImageLocation loc) {
	String base = loc.getBaseString();
	String ext = loc.getExtensionString();
	if (ext != null && !ext.isEmpty()) {
	base = base + "." + ext;
	}
	return base;
	}
	}

	public synchronized Node findNode(UTF8String name) {
	buildRootDirectory();
	Node n = nodes.get(name);
	if (n == null \|\| !n.isCompleted()) {
	NodeBuilder builder = new NodeBuilder(name);
	n = builder.buildNode();
	}
	return n;
	}

	private synchronized void clearNodes() {
	nodes.clear();
	rootDir = null;
	}

	/**
	* Returns the file attributes of the image file.
	*/
	private BasicFileAttributes imageFileAttributes() {
	BasicFileAttributes attrs = imageFileAttributes;
	if (attrs == null) {
	try {
	Path file = Paths.get(imagePath());
	attrs = Files.readAttributes(file, BasicFileAttributes.class);
	} catch (IOException ioe) {
	throw new UncheckedIOException(ioe);
	}
	imageFileAttributes = attrs;
	}
	return attrs;
	}

	private synchronized Directory buildRootDirectory() {
	if (rootDir != null) {
	return rootDir;
	}

	// FIXME no time information per resource in jimage file (yet?)
	// we use file attributes of jimage itself.
	// root directory
	rootDir = newDirectory(null, ROOT_STRING);
	rootDir.setIsRootDir();

	// /packages dir
	packagesDir = newDirectory(rootDir, PACKAGES_STRING);
	packagesDir.setIsPackagesDir();

	// /modules dir
	modulesDir = newDirectory(rootDir, MODULES_STRING);
	modulesDir.setIsModulesDir();

	rootDir.setCompleted(true);
	return rootDir;
	}

	private Directory newDirectory(Directory parent, UTF8String name) {
	Directory dir = Directory.create(parent, name, imageFileAttributes());
	nodes.put(dir.getName(), dir);
	return dir;
	}

	private Resource newResource(Directory parent, ImageLocation loc) {
	Resource res = Resource.create(parent, loc, imageFileAttributes());
	nodes.put(res.getName(), res);
	return res;
	}

	private LinkNode newLinkNode(Directory dir, UTF8String name, Node link) {
	LinkNode linkNode = LinkNode.create(dir, name, link);
	nodes.put(linkNode.getName(), linkNode);
	return linkNode;
	}

	private List<UTF8String> dirs(UTF8String parent) {
	List<UTF8String> splits = new ArrayList<>();

	for (int i = 1; i < parent.length(); i++) {
	if (parent.byteAt(i) == '/') {
	splits.add(parent.substring(0, i));
	}
	}

	splits.add(parent);

	return splits;
	}

	private Directory makeDirectories(UTF8String parent) {
	Directory last = rootDir;
	List<UTF8String> dirs = dirs(parent);

	for (UTF8String dir : dirs) {
	Directory nextDir = (Directory) nodes.get(dir);
	if (nextDir == null) {
	nextDir = newDirectory(last, dir);
	}
	last = nextDir;
	}

	return last;
	}

	public byte[] getResource(Node node) throws IOException {
	if (node.isResource()) {
	return super.getResource(node.getLocation());
	}
	throw new IOException("Not a resource: " + node);
	}

	public byte[] getResource(Resource rs) throws IOException {
	return super.getResource(rs.getLocation());
	}
	}