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src/java.base/share/classes/jdk/internal/jrtfs/ExplodedImage.java

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  1 /*
  2  * Copyright (c) 2015, 2022, Oracle and/or its affiliates. All rights reserved.
  3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  4  *
  5  * This code is free software; you can redistribute it and/or modify it
  6  * under the terms of the GNU General Public License version 2 only, as
  7  * published by the Free Software Foundation.  Oracle designates this
  8  * particular file as subject to the "Classpath" exception as provided
  9  * by Oracle in the LICENSE file that accompanied this code.
 10  *
 11  * This code is distributed in the hope that it will be useful, but WITHOUT
 12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 14  * version 2 for more details (a copy is included in the LICENSE file that
 15  * accompanied this code).
 16  *
 17  * You should have received a copy of the GNU General Public License version
 18  * 2 along with this work; if not, write to the Free Software Foundation,
 19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 20  *
 21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 22  * or visit www.oracle.com if you need additional information or have any
 23  * questions.
 24  */
 25 package jdk.internal.jrtfs;
 26 
 27 import java.io.IOException;
 28 import java.io.UncheckedIOException;
 29 import java.nio.file.DirectoryStream;
 30 import java.nio.file.FileSystem;
 31 import java.nio.file.FileSystemException;
 32 import java.nio.file.FileSystems;
 33 import java.nio.file.Files;
 34 import java.nio.file.Path;
 35 import java.nio.file.attribute.BasicFileAttributes;
 36 import java.util.ArrayList;
 37 import java.util.Collections;
 38 import java.util.HashMap;
 39 import java.util.List;
 40 import java.util.Map;

 41 import java.util.stream.Stream;
 42 
 43 import jdk.internal.jimage.ImageReader.Node;
 44 
 45 /**
 46  * A jrt file system built on $JAVA_HOME/modules directory ('exploded modules
 47  * build')
 48  *
 49  * @implNote This class needs to maintain JDK 8 source compatibility.
 50  *
 51  * It is used internally in the JDK to implement jimage/jrtfs access,
 52  * but also compiled and delivered as part of the jrtfs.jar to support access
 53  * to the jimage file provided by the shipped JDK by tools running on JDK 8.
 54  */
 55 class ExplodedImage extends SystemImage {
 56 
 57     private static final String MODULES = "/modules/";
 58     private static final String PACKAGES = "/packages/";
 59     private static final int PACKAGES_LEN = PACKAGES.length();
 60 
 61     private final FileSystem defaultFS;
 62     private final String separator;
 63     private final Map<String, PathNode> nodes = Collections.synchronizedMap(new HashMap<>());
 64     private final BasicFileAttributes modulesDirAttrs;
 65 
 66     ExplodedImage(Path modulesDir) throws IOException {
 67         defaultFS = FileSystems.getDefault();
 68         String str = defaultFS.getSeparator();
 69         separator = str.equals("/") ? null : str;
 70         modulesDirAttrs = Files.readAttributes(modulesDir, BasicFileAttributes.class);
 71         initNodes();
 72     }
 73 
 74     // A Node that is backed by actual default file system Path
 75     private final class PathNode extends Node {
 76 
 77         // Path in underlying default file system
 78         private Path path;
 79         private PathNode link;
 80         private List<Node> children;
 81 
 82         PathNode(String name, Path path, BasicFileAttributes attrs) {  // path
 83             super(name, attrs);
 84             this.path = path;
 85         }
 86 
 87         PathNode(String name, Node link) {              // link
 88             super(name, link.getFileAttributes());
 89             this.link = (PathNode)link;
 90         }
 91 
 92         PathNode(String name, List<Node> children) {    // dir
 93             super(name, modulesDirAttrs);
 94             this.children = children;
 95         }
 96 





 97         @Override
 98         public boolean isDirectory() {
 99             return children != null ||
100                    (link == null && getFileAttributes().isDirectory());
101         }
102 
103         @Override
104         public boolean isLink() {
105             return link != null;
106         }
107 
108         @Override
109         public PathNode resolveLink(boolean recursive) {
110             if (link == null)
111                 return this;
112             return recursive && link.isLink() ? link.resolveLink(true) : link;
113         }
114 
115         byte[] getContent() throws IOException {
116             if (!getFileAttributes().isRegularFile())
117                 throw new FileSystemException(getName() + " is not file");
118             return Files.readAllBytes(path);
119         }
120 
121         @Override
122         public Stream<String> getChildNames() {
123             if (!isDirectory())
124                 throw new IllegalArgumentException("not a directory: " + getName());
125             if (children == null) {
126                 List<Node> list = new ArrayList<>();
127                 try (DirectoryStream<Path> stream = Files.newDirectoryStream(path)) {
128                     for (Path p : stream) {
129                         p = explodedModulesDir.relativize(p);
130                         String pName = MODULES + nativeSlashToFrontSlash(p.toString());
131                         Node node = findNode(pName);
132                         if (node != null) {  // findNode may choose to hide certain files!
133                             list.add(node);
134                         }
135                     }
136                 } catch (IOException x) {
137                     return null;
138                 }
139                 children = list;
140             }
141             return children.stream().map(Node::getName);
142         }
143 
144         @Override
145         public long size() {
146             try {
147                 return isDirectory() ? 0 : Files.size(path);
148             } catch (IOException ex) {
149                 throw new UncheckedIOException(ex);
150             }
151         }
152     }
153 
154     @Override
155     public void close() throws IOException {
156         nodes.clear();
157     }
158 
159     @Override
160     public byte[] getResource(Node node) throws IOException {
161         return ((PathNode)node).getContent();
162     }
163 
164     // find Node for the given Path
165     @Override
166     public synchronized Node findNode(String str) {
167         Node node = findModulesNode(str);
168         if (node != null) {
169             return node;
170         }
171         // lazily created for paths like /packages/<package>/<module>/xyz
172         // For example /packages/java.lang/java.base/java/lang/
173         if (str.startsWith(PACKAGES)) {
174             // pkgEndIdx marks end of <package> part
175             int pkgEndIdx = str.indexOf('/', PACKAGES_LEN);
176             if (pkgEndIdx != -1) {
177                 // modEndIdx marks end of <module> part
178                 int modEndIdx = str.indexOf('/', pkgEndIdx + 1);
179                 if (modEndIdx != -1) {
180                     // make sure we have such module link!
181                     // ie., /packages/<package>/<module> is valid
182                     Node linkNode = nodes.get(str.substring(0, modEndIdx));
183                     if (linkNode == null || !linkNode.isLink()) {
184                         return null;
185                     }
186                     // map to "/modules/zyz" path and return that node
187                     // For example, "/modules/java.base/java/lang" for
188                     // "/packages/java.lang/java.base/java/lang".
189                     String mod = MODULES + str.substring(pkgEndIdx + 1);
190                     return findModulesNode(mod);
191                 }
192             }
193         }
194         return null;

195     }
196 
197     // find a Node for a path that starts like "/modules/..."
198     Node findModulesNode(String str) {
199         PathNode node = nodes.get(str);
200         if (node != null) {
201             return node;
202         }
203         // lazily created "/modules/xyz/abc/" Node
204         // This is mapped to default file system path "<JDK_MODULES_DIR>/xyz/abc"
205         Path p = underlyingPath(str);
206         if (p != null) {
207             try {
208                 BasicFileAttributes attrs = Files.readAttributes(p, BasicFileAttributes.class);
209                 if (attrs.isRegularFile()) {
210                     Path f = p.getFileName();
211                     if (f.toString().startsWith("_the."))
212                         return null;







213                 }
214                 node = new PathNode(str, p, attrs);
215                 nodes.put(str, node);
216                 return node;
217             } catch (IOException x) {
218                 // does not exists or unable to determine
219             }






220         }
221         return null;
222     }
223 
224     Path underlyingPath(String str) {
225         if (str.startsWith(MODULES)) {
226             str = frontSlashToNativeSlash(str.substring("/modules".length()));
227             return defaultFS.getPath(explodedModulesDir.toString(), str);





228         }
229         return null;
230     }
231 






232     // convert "/" to platform path separator
233     private String frontSlashToNativeSlash(String str) {
234         return separator == null ? str : str.replace("/", separator);
235     }
236 
237     // convert platform path separator to "/"
238     private String nativeSlashToFrontSlash(String str) {
239         return separator == null ? str : str.replace(separator, "/");
240     }
241 
242     // convert "/"s to "."s
243     private String slashesToDots(String str) {
244         return str.replace(separator != null ? separator : "/", ".");
245     }
246 
247     // initialize file system Nodes
248     private void initNodes() throws IOException {
249         // same package prefix may exist in multiple modules. This Map
250         // is filled by walking "jdk modules" directory recursively!
251         Map<String, List<String>> packageToModules = new HashMap<>();
252         try (DirectoryStream<Path> stream = Files.newDirectoryStream(explodedModulesDir)) {
253             for (Path module : stream) {
254                 if (Files.isDirectory(module)) {
255                     String moduleName = module.getFileName().toString();
256                     // make sure "/modules/<moduleName>" is created
257                     findModulesNode(MODULES + moduleName);
258                     try (Stream<Path> contentsStream = Files.walk(module)) {
259                         contentsStream.filter(Files::isDirectory).forEach((p) -> {
260                             p = module.relativize(p);
261                             String pkgName = slashesToDots(p.toString());
262                             // skip META-INF and empty strings
263                             if (!pkgName.isEmpty() && !pkgName.startsWith("META-INF")) {
264                                 List<String> moduleNames = packageToModules.get(pkgName);
265                                 if (moduleNames == null) {
266                                     moduleNames = new ArrayList<>();
267                                     packageToModules.put(pkgName, moduleNames);
268                                 }
269                                 moduleNames.add(moduleName);
270                             }
271                         });
272                     }
273                 }
274             }
275         }
276         // create "/modules" directory
277         // "nodes" map contains only /modules/<foo> nodes only so far and so add all as children of /modules
278         PathNode modulesDir = new PathNode("/modules", new ArrayList<>(nodes.values()));
279         nodes.put(modulesDir.getName(), modulesDir);
280 
281         // create children under "/packages"
282         List<Node> packagesChildren = new ArrayList<>(packageToModules.size());
283         for (Map.Entry<String, List<String>> entry : packageToModules.entrySet()) {
284             String pkgName = entry.getKey();
285             List<String> moduleNameList = entry.getValue();
286             List<Node> moduleLinkNodes = new ArrayList<>(moduleNameList.size());
287             for (String moduleName : moduleNameList) {
288                 Node moduleNode = findModulesNode(MODULES + moduleName);
289                 PathNode linkNode = new PathNode(PACKAGES + pkgName + "/" + moduleName, moduleNode);
290                 nodes.put(linkNode.getName(), linkNode);
291                 moduleLinkNodes.add(linkNode);
292             }
293             PathNode pkgDir = new PathNode(PACKAGES + pkgName, moduleLinkNodes);
294             nodes.put(pkgDir.getName(), pkgDir);
295             packagesChildren.add(pkgDir);
296         }
297         // "/packages" dir
298         PathNode packagesDir = new PathNode("/packages", packagesChildren);
299         nodes.put(packagesDir.getName(), packagesDir);
300 
301         // finally "/" dir!
302         List<Node> rootChildren = new ArrayList<>();
303         rootChildren.add(packagesDir);
304         rootChildren.add(modulesDir);
305         PathNode root = new PathNode("/", rootChildren);
306         nodes.put(root.getName(), root);
307     }
308 }

  1 /*
  2  * Copyright (c) 2015, 2025, Oracle and/or its affiliates. All rights reserved.
  3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  4  *
  5  * This code is free software; you can redistribute it and/or modify it
  6  * under the terms of the GNU General Public License version 2 only, as
  7  * published by the Free Software Foundation.  Oracle designates this
  8  * particular file as subject to the "Classpath" exception as provided
  9  * by Oracle in the LICENSE file that accompanied this code.
 10  *
 11  * This code is distributed in the hope that it will be useful, but WITHOUT
 12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 14  * version 2 for more details (a copy is included in the LICENSE file that
 15  * accompanied this code).
 16  *
 17  * You should have received a copy of the GNU General Public License version
 18  * 2 along with this work; if not, write to the Free Software Foundation,
 19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 20  *
 21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 22  * or visit www.oracle.com if you need additional information or have any
 23  * questions.
 24  */
 25 package jdk.internal.jrtfs;
 26 
 27 import java.io.IOException;
 28 import java.io.UncheckedIOException;
 29 import java.nio.file.DirectoryStream;

 30 import java.nio.file.FileSystemException;

 31 import java.nio.file.Files;
 32 import java.nio.file.Path;
 33 import java.nio.file.attribute.BasicFileAttributes;
 34 import java.util.ArrayList;

 35 import java.util.HashMap;
 36 import java.util.List;
 37 import java.util.Map;
 38 import java.util.Objects;
 39 import java.util.stream.Stream;
 40 
 41 import jdk.internal.jimage.ImageReader.Node;
 42 
 43 /**
 44  * A jrt file system built on $JAVA_HOME/modules directory ('exploded modules
 45  * build')
 46  *
 47  * @implNote This class needs to maintain JDK 8 source compatibility.
 48  *
 49  * It is used internally in the JDK to implement jimage/jrtfs access,
 50  * but also compiled and delivered as part of the jrtfs.jar to support access
 51  * to the jimage file provided by the shipped JDK by tools running on JDK 8.
 52  */
 53 class ExplodedImage extends SystemImage {
 54 
 55     private static final String MODULES = "/modules/";
 56     private static final String PACKAGES = "/packages/";

 57 
 58     private final Path modulesDir;
 59     private final String separator;
 60     private final Map<String, PathNode> nodes = new HashMap<>();
 61     private final BasicFileAttributes modulesDirAttrs;
 62 
 63     ExplodedImage(Path modulesDir) throws IOException {
 64         this.modulesDir = modulesDir;
 65         String str = modulesDir.getFileSystem().getSeparator();
 66         separator = str.equals("/") ? null : str;
 67         modulesDirAttrs = Files.readAttributes(modulesDir, BasicFileAttributes.class);
 68         initNodes();
 69     }
 70 
 71     // A Node that is backed by actual default file system Path
 72     private final class PathNode extends Node {
 73 
 74         // Path in underlying default file system
 75         private Path path;
 76         private PathNode link;
 77         private List<Node> children;
 78 
 79         private PathNode(String name, Path path, BasicFileAttributes attrs) {  // path
 80             super(name, attrs);
 81             this.path = path;
 82         }
 83 
 84         private PathNode(String name, Node link) {              // link
 85             super(name, link.getFileAttributes());
 86             this.link = (PathNode)link;
 87         }
 88 
 89         private PathNode(String name, List<Node> children) {    // dir
 90             super(name, modulesDirAttrs);
 91             this.children = children;
 92         }
 93 
 94         @Override
 95         public boolean isResource() {
 96             return link == null && !getFileAttributes().isDirectory();
 97         }
 98 
 99         @Override
100         public boolean isDirectory() {
101             return children != null ||
102                    (link == null && getFileAttributes().isDirectory());
103         }
104 
105         @Override
106         public boolean isLink() {
107             return link != null;
108         }
109 
110         @Override
111         public PathNode resolveLink(boolean recursive) {
112             if (link == null)
113                 return this;
114             return recursive && link.isLink() ? link.resolveLink(true) : link;
115         }
116 
117         private byte[] getContent() throws IOException {
118             if (!getFileAttributes().isRegularFile())
119                 throw new FileSystemException(getName() + " is not file");
120             return Files.readAllBytes(path);
121         }
122 
123         @Override
124         public Stream<String> getChildNames() {
125             if (!isDirectory())
126                 throw new IllegalArgumentException("not a directory: " + getName());
127             if (children == null) {
128                 List<Node> list = new ArrayList<>();
129                 try (DirectoryStream<Path> stream = Files.newDirectoryStream(path)) {
130                     for (Path p : stream) {
131                         p = modulesDir.relativize(p);
132                         String pName = MODULES + nativeSlashToFrontSlash(p.toString());
133                         Node node = findNode(pName);
134                         if (node != null) {  // findNode may choose to hide certain files!
135                             list.add(node);
136                         }
137                     }
138                 } catch (IOException x) {
139                     return null;
140                 }
141                 children = list;
142             }
143             return children.stream().map(Node::getName);
144         }
145 
146         @Override
147         public long size() {
148             try {
149                 return isDirectory() ? 0 : Files.size(path);
150             } catch (IOException ex) {
151                 throw new UncheckedIOException(ex);
152             }
153         }
154     }
155 
156     @Override
157     public synchronized void close() throws IOException {
158         nodes.clear();
159     }
160 
161     @Override
162     public byte[] getResource(Node node) throws IOException {
163         return ((PathNode)node).getContent();
164     }
165 

166     @Override
167     public synchronized Node findNode(String name) {
168         PathNode node = nodes.get(name);
169         if (node != null) {
170             return node;
171         }
172         // If null, this was not the name of "/modules/..." node, and since all
173         // "/packages/..." nodes were created and cached in advance, the name
174         // cannot reference a valid node.
175         Path path = underlyingModulesPath(name);
176         if (path == null) {
177             return null;
















178         }
179         // This can still return null for hidden files.
180         return createModulesNode(name, path);
181     }
182 
183     /**
184      * Lazily creates and caches a {@code Node} for the given "/modules/..." name
185      * and corresponding path to a file or directory.
186      *
187      * @param name a resource or directory node name, of the form "/modules/...".
188      * @param path the path of a file for a resource or directory.
189      * @return the newly created and cached node, or {@code null} if the given
190      *     path references a file which must be hidden in the node hierarchy.
191      */
192     private Node createModulesNode(String name, Path path) {
193         assert !nodes.containsKey(name) : "Node must not already exist: " + name;
194         assert isNonEmptyModulesPath(name) : "Invalid modules name: " + name;
195 
196         try {
197             // We only know if we're creating a resource of directory when we
198             // look up file attributes, and we only do that once. Thus, we can
199             // only reject "marker files" here, rather than by inspecting the
200             // given name string, since it doesn't apply to directories.
201             BasicFileAttributes attrs = Files.readAttributes(path, BasicFileAttributes.class);
202             if (attrs.isRegularFile()) {
203                 Path f = path.getFileName();
204                 if (f.toString().startsWith("_the.")) {
205                     return null;
206                 }
207             } else if (!attrs.isDirectory()) {
208                 return null;



209             }
210             PathNode node = new PathNode(name, path, attrs);
211             nodes.put(name, node);
212             return node;
213         } catch (IOException x) {
214             // Since the path reference a file, any errors should not be ignored.
215             throw new UncheckedIOException(x);
216         }

217     }
218 
219     /**
220      * Returns the expected file path for name in the "/modules/..." namespace,
221      * or {@code null} if the name is not in the "/modules/..." namespace or the
222      * path does not reference a file.
223      */
224     private Path underlyingModulesPath(String name) {
225         if (isNonEmptyModulesPath(name)) {
226             Path path = modulesDir.resolve(frontSlashToNativeSlash(name.substring(MODULES.length())));
227             return Files.exists(path) ? path : null;
228         }
229         return null;
230     }
231 
232     private static boolean isNonEmptyModulesPath(String name) {
233         // Don't just check the prefix, there must be something after it too
234         // (otherwise you end up with an empty string after trimming).
235         return name.startsWith(MODULES) && name.length() > MODULES.length();
236     }
237 
238     // convert "/" to platform path separator
239     private String frontSlashToNativeSlash(String str) {
240         return separator == null ? str : str.replace("/", separator);
241     }
242 
243     // convert platform path separator to "/"
244     private String nativeSlashToFrontSlash(String str) {
245         return separator == null ? str : str.replace(separator, "/");
246     }
247 
248     // convert "/"s to "."s
249     private String slashesToDots(String str) {
250         return str.replace(separator != null ? separator : "/", ".");
251     }
252 
253     // initialize file system Nodes
254     private void initNodes() throws IOException {
255         // same package prefix may exist in multiple modules. This Map
256         // is filled by walking "jdk modules" directory recursively!
257         Map<String, List<String>> packageToModules = new HashMap<>();
258         try (DirectoryStream<Path> stream = Files.newDirectoryStream(modulesDir)) {
259             for (Path module : stream) {
260                 if (Files.isDirectory(module)) {
261                     String moduleName = module.getFileName().toString();
262                     // make sure "/modules/<moduleName>" is created
263                     Objects.requireNonNull(createModulesNode(MODULES + moduleName, module));
264                     try (Stream<Path> contentsStream = Files.walk(module)) {
265                         contentsStream.filter(Files::isDirectory).forEach((p) -> {
266                             p = module.relativize(p);
267                             String pkgName = slashesToDots(p.toString());
268                             // skip META-INF and empty strings
269                             if (!pkgName.isEmpty() && !pkgName.startsWith("META-INF")) {
270                                 packageToModules
271                                         .computeIfAbsent(pkgName, k -> new ArrayList<>())
272                                         .add(moduleName);



273                             }
274                         });
275                     }
276                 }
277             }
278         }
279         // create "/modules" directory
280         // "nodes" map contains only /modules/<foo> nodes only so far and so add all as children of /modules
281         PathNode modulesRootNode = new PathNode("/modules", new ArrayList<>(nodes.values()));
282         nodes.put(modulesRootNode.getName(), modulesRootNode);
283 
284         // create children under "/packages"
285         List<Node> packagesChildren = new ArrayList<>(packageToModules.size());
286         for (Map.Entry<String, List<String>> entry : packageToModules.entrySet()) {
287             String pkgName = entry.getKey();
288             List<String> moduleNameList = entry.getValue();
289             List<Node> moduleLinkNodes = new ArrayList<>(moduleNameList.size());
290             for (String moduleName : moduleNameList) {
291                 Node moduleNode = Objects.requireNonNull(nodes.get(MODULES + moduleName));
292                 PathNode linkNode = new PathNode(PACKAGES + pkgName + "/" + moduleName, moduleNode);
293                 nodes.put(linkNode.getName(), linkNode);
294                 moduleLinkNodes.add(linkNode);
295             }
296             PathNode pkgDir = new PathNode(PACKAGES + pkgName, moduleLinkNodes);
297             nodes.put(pkgDir.getName(), pkgDir);
298             packagesChildren.add(pkgDir);
299         }
300         // "/packages" dir
301         PathNode packagesRootNode = new PathNode("/packages", packagesChildren);
302         nodes.put(packagesRootNode.getName(), packagesRootNode);
303 
304         // finally "/" dir!
305         List<Node> rootChildren = new ArrayList<>();
306         rootChildren.add(packagesRootNode);
307         rootChildren.add(modulesRootNode);
308         PathNode root = new PathNode("/", rootChildren);
309         nodes.put(root.getName(), root);
310     }
311 }
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