1 /*
2 * Copyright (c) 2014, 2017, 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
26 package jdk.internal.module;
27
28 import java.io.BufferedInputStream;
29 import java.io.BufferedReader;
30 import java.io.File;
31 import java.io.IOException;
32 import java.io.InputStream;
33 import java.io.InputStreamReader;
34 import java.io.UncheckedIOException;
35 import java.lang.module.FindException;
36 import java.lang.module.InvalidModuleDescriptorException;
37 import java.lang.module.ModuleDescriptor;
38 import java.lang.module.ModuleDescriptor.Builder;
39 import java.lang.module.ModuleFinder;
40 import java.lang.module.ModuleReference;
41 import java.net.URI;
42 import java.nio.file.DirectoryStream;
43 import java.nio.file.Files;
44 import java.nio.file.NoSuchFileException;
45 import java.nio.file.Path;
46 import java.nio.file.Paths;
47 import java.nio.file.attribute.BasicFileAttributes;
48 import java.util.ArrayList;
49 import java.util.Collections;
50 import java.util.HashMap;
51 import java.util.List;
52 import java.util.Map;
53 import java.util.Objects;
54 import java.util.Optional;
55 import java.util.Set;
56 import java.util.jar.Attributes;
57 import java.util.jar.JarEntry;
58 import java.util.jar.JarFile;
59 import java.util.jar.Manifest;
60 import java.util.regex.Matcher;
61 import java.util.regex.Pattern;
62 import java.util.stream.Collectors;
63 import java.util.zip.ZipException;
64 import java.util.zip.ZipFile;
65
66 import jdk.internal.jmod.JmodFile;
67 import jdk.internal.jmod.JmodFile.Section;
68 import jdk.internal.perf.PerfCounter;
69
70 /**
71 * A {@code ModuleFinder} that locates modules on the file system by searching
72 * a sequence of directories or packaged modules. The ModuleFinder can be
73 * created to work in either the run-time or link-time phases. In both cases it
74 * locates modular JAR and exploded modules. When created for link-time then it
75 * additionally locates modules in JMOD files. The ModuleFinder can also
76 * optionally patch any modules that it locates with a ModulePatcher.
77 */
78
79 public class ModulePath implements ModuleFinder {
80 private static final String MODULE_INFO = "module-info.class";
81
82 // the version to use for multi-release modular JARs
83 private final Runtime.Version releaseVersion;
84
85 // true for the link phase (supports modules packaged in JMOD format)
86 private final boolean isLinkPhase;
87
88 // for patching modules, can be null
89 private final ModulePatcher patcher;
90
91 // the entries on this module path
92 private final Path[] entries;
93 private int next;
94
95 // map of module name to module reference map for modules already located
96 private final Map<String, ModuleReference> cachedModules = new HashMap<>();
97
98
99 private ModulePath(Runtime.Version version,
100 boolean isLinkPhase,
101 ModulePatcher patcher,
102 Path... entries) {
103 this.releaseVersion = version;
104 this.isLinkPhase = isLinkPhase;
105 this.patcher = patcher;
106 this.entries = entries.clone();
107 for (Path entry : this.entries) {
108 Objects.requireNonNull(entry);
109 }
110 }
111
112 /**
113 * Returns a ModuleFinder that locates modules on the file system by
114 * searching a sequence of directories and/or packaged modules. The modules
115 * may be patched by the given ModulePatcher.
116 */
117 public static ModuleFinder of(ModulePatcher patcher, Path... entries) {
118 return new ModulePath(JarFile.runtimeVersion(), false, patcher, entries);
119 }
120
121 /**
122 * Returns a ModuleFinder that locates modules on the file system by
123 * searching a sequence of directories and/or packaged modules.
124 */
125 public static ModuleFinder of(Path... entries) {
126 return of((ModulePatcher)null, entries);
127 }
128
129 /**
130 * Returns a ModuleFinder that locates modules on the file system by
131 * searching a sequence of directories and/or packaged modules.
132 *
133 * @param version The release version to use for multi-release JAR files
134 * @param isLinkPhase {@code true} if the link phase to locate JMOD files
135 */
136 public static ModuleFinder of(Runtime.Version version,
137 boolean isLinkPhase,
138 Path... entries) {
139 return new ModulePath(version, isLinkPhase, null, entries);
140 }
141
142
143 @Override
144 public Optional<ModuleReference> find(String name) {
145 Objects.requireNonNull(name);
146
147 // try cached modules
148 ModuleReference m = cachedModules.get(name);
149 if (m != null)
150 return Optional.of(m);
151
152 // the module may not have been encountered yet
153 while (hasNextEntry()) {
154 scanNextEntry();
155 m = cachedModules.get(name);
156 if (m != null)
157 return Optional.of(m);
158 }
159 return Optional.empty();
160 }
161
162 @Override
163 public Set<ModuleReference> findAll() {
164 // need to ensure that all entries have been scanned
165 while (hasNextEntry()) {
166 scanNextEntry();
167 }
168 return cachedModules.values().stream().collect(Collectors.toSet());
169 }
170
171 /**
172 * Returns {@code true} if there are additional entries to scan
173 */
174 private boolean hasNextEntry() {
175 return next < entries.length;
176 }
177
178 /**
179 * Scans the next entry on the module path. A no-op if all entries have
180 * already been scanned.
181 *
182 * @throws FindException if an error occurs scanning the next entry
183 */
184 private void scanNextEntry() {
185 if (hasNextEntry()) {
186
187 long t0 = System.nanoTime();
188
189 Path entry = entries[next];
190 Map<String, ModuleReference> modules = scan(entry);
191 next++;
192
193 // update cache, ignoring duplicates
194 int initialSize = cachedModules.size();
195 for (Map.Entry<String, ModuleReference> e : modules.entrySet()) {
196 cachedModules.putIfAbsent(e.getKey(), e.getValue());
197 }
198
199 // update counters
200 int added = cachedModules.size() - initialSize;
201 moduleCount.add(added);
202
203 scanTime.addElapsedTimeFrom(t0);
204 }
205 }
206
207
208 /**
209 * Scan the given module path entry. If the entry is a directory then it is
210 * a directory of modules or an exploded module. If the entry is a regular
211 * file then it is assumed to be a packaged module.
212 *
213 * @throws FindException if an error occurs scanning the entry
214 */
215 private Map<String, ModuleReference> scan(Path entry) {
216
217 BasicFileAttributes attrs;
218 try {
219 attrs = Files.readAttributes(entry, BasicFileAttributes.class);
220 } catch (NoSuchFileException e) {
221 return Collections.emptyMap();
222 } catch (IOException ioe) {
223 throw new FindException(ioe);
224 }
225
226 try {
227
228 if (attrs.isDirectory()) {
229 Path mi = entry.resolve(MODULE_INFO);
230 if (!Files.exists(mi)) {
231 // assume a directory of modules
232 return scanDirectory(entry);
233 }
234 }
235
236 // packaged or exploded module
237 ModuleReference mref = readModule(entry, attrs);
238 if (mref != null) {
239 String name = mref.descriptor().name();
240 return Collections.singletonMap(name, mref);
241 }
242
243 // not recognized
244 String msg;
245 if (!isLinkPhase && entry.toString().endsWith(".jmod")) {
246 msg = "JMOD format not supported at execution time";
247 } else {
248 msg = "Module format not recognized";
249 }
250 throw new FindException(msg + ": " + entry);
251
252 } catch (IOException ioe) {
253 throw new FindException(ioe);
254 }
255 }
256
257
258 /**
259 * Scans the given directory for packaged or exploded modules.
260 *
261 * @return a map of module name to ModuleReference for the modules found
262 * in the directory
263 *
264 * @throws IOException if an I/O error occurs
265 * @throws FindException if an error occurs scanning the entry or the
266 * directory contains two or more modules with the same name
267 */
268 private Map<String, ModuleReference> scanDirectory(Path dir)
269 throws IOException
270 {
271 // The map of name -> mref of modules found in this directory.
272 Map<String, ModuleReference> nameToReference = new HashMap<>();
273
274 try (DirectoryStream<Path> stream = Files.newDirectoryStream(dir)) {
275 for (Path entry : stream) {
276 BasicFileAttributes attrs;
277 try {
278 attrs = Files.readAttributes(entry, BasicFileAttributes.class);
279 } catch (NoSuchFileException ignore) {
280 // file has been removed or moved, ignore for now
281 continue;
282 }
283
284 ModuleReference mref = readModule(entry, attrs);
285
286 // module found
287 if (mref != null) {
288 // can have at most one version of a module in the directory
289 String name = mref.descriptor().name();
290 ModuleReference previous = nameToReference.put(name, mref);
291 if (previous != null) {
292 String fn1 = fileName(mref);
293 String fn2 = fileName(previous);
294 throw new FindException("Two versions of module "
295 + name + " found in " + dir
296 + " (" + fn1 + " and " + fn2 + ")");
297 }
298 }
299 }
300 }
301
302 return nameToReference;
303 }
304
305
306 /**
307 * Reads a packaged or exploded module, returning a {@code ModuleReference}
308 * to the module. Returns {@code null} if the entry is not recognized.
309 *
310 * @throws IOException if an I/O error occurs
311 * @throws FindException if an error occurs parsing its module descriptor
312 */
313 private ModuleReference readModule(Path entry, BasicFileAttributes attrs)
314 throws IOException
315 {
316 try {
317
318 // exploded module
319 if (attrs.isDirectory()) {
320 return readExplodedModule(entry); // may return null
321 }
322
323 // JAR or JMOD file
324 if (attrs.isRegularFile()) {
325 String fn = entry.getFileName().toString();
326 boolean isDefaultFileSystem = isDefaultFileSystem(entry);
327
328 // JAR file
329 if (fn.endsWith(".jar")) {
330 if (isDefaultFileSystem) {
331 return readJar(entry);
332 } else {
333 // the JAR file is in a custom file system so
334 // need to copy it to the local file system
335 Path tmpdir = Files.createTempDirectory("mlib");
336 Path target = Files.copy(entry, tmpdir.resolve(fn));
337 return readJar(target);
338 }
339 }
340
341 // JMOD file
342 if (isDefaultFileSystem && isLinkPhase && fn.endsWith(".jmod")) {
343 return readJMod(entry);
344 }
345 }
346
347 return null;
348
349 } catch (InvalidModuleDescriptorException e) {
350 throw new FindException("Error reading module: " + entry, e);
351 }
352 }
353
354 /**
355 * Returns a string with the file name of the module if possible.
356 * If the module location is not a file URI then return the URI
357 * as a string.
358 */
359 private String fileName(ModuleReference mref) {
360 URI uri = mref.location().orElse(null);
361 if (uri != null) {
362 if (uri.getScheme().equalsIgnoreCase("file")) {
363 Path file = Paths.get(uri);
364 return file.getFileName().toString();
365 } else {
366 return uri.toString();
367 }
368 } else {
369 return "<unknown>";
370 }
371 }
372
373 // -- JMOD files --
374
375 private Set<String> jmodPackages(JmodFile jf) {
376 return jf.stream()
377 .filter(e -> e.section() == Section.CLASSES)
378 .map(JmodFile.Entry::name)
379 .map(this::toPackageName)
380 .flatMap(Optional::stream)
381 .collect(Collectors.toSet());
382 }
383
384 /**
385 * Returns a {@code ModuleReference} to a module in JMOD file on the
386 * file system.
387 *
388 * @throws IOException
389 * @throws InvalidModuleDescriptorException
390 */
391 private ModuleReference readJMod(Path file) throws IOException {
392 try (JmodFile jf = new JmodFile(file)) {
393 ModuleInfo.Attributes attrs;
394 try (InputStream in = jf.getInputStream(Section.CLASSES, MODULE_INFO)) {
395 attrs = ModuleInfo.read(in, () -> jmodPackages(jf));
396 }
397 return ModuleReferences.newJModModule(attrs, file);
398 }
399 }
400
401
402 // -- JAR files --
403
404 private static final String SERVICES_PREFIX = "META-INF/services/";
405
406 private static final Attributes.Name AUTOMATIC_MODULE_NAME
407 = new Attributes.Name("Automatic-Module-Name");
408
409 /**
410 * Returns the service type corresponding to the name of a services
411 * configuration file if it is a legal type name.
412 *
413 * For example, if called with "META-INF/services/p.S" then this method
414 * returns a container with the value "p.S".
415 */
416 private Optional<String> toServiceName(String cf) {
417 assert cf.startsWith(SERVICES_PREFIX);
418 int index = cf.lastIndexOf("/") + 1;
419 if (index < cf.length()) {
420 String prefix = cf.substring(0, index);
421 if (prefix.equals(SERVICES_PREFIX)) {
422 String sn = cf.substring(index);
423 if (Checks.isClassName(sn))
424 return Optional.of(sn);
425 }
426 }
427 return Optional.empty();
428 }
429
430 /**
431 * Reads the next line from the given reader and trims it of comments and
432 * leading/trailing white space.
433 *
434 * Returns null if the reader is at EOF.
435 */
436 private String nextLine(BufferedReader reader) throws IOException {
437 String ln = reader.readLine();
438 if (ln != null) {
439 int ci = ln.indexOf('#');
440 if (ci >= 0)
441 ln = ln.substring(0, ci);
442 ln = ln.trim();
443 }
444 return ln;
445 }
446
447 /**
448 * Treat the given JAR file as a module as follows:
449 *
450 * 1. The value of the Automatic-Module-Name attribute is the module name
451 * 2. The version, and the module name when the Automatic-Module-Name
452 * attribute is not present, is derived from the file ame of the JAR file
453 * 3. All packages are derived from the .class files in the JAR file
454 * 4. The contents of any META-INF/services configuration files are mapped
455 * to "provides" declarations
456 * 5. The Main-Class attribute in the main attributes of the JAR manifest
457 * is mapped to the module descriptor mainClass if possible
458 */
459 private ModuleDescriptor deriveModuleDescriptor(JarFile jf)
460 throws IOException
461 {
462 // Read Automatic-Module-Name attribute if present
463 Manifest man = jf.getManifest();
464 Attributes attrs = null;
465 String moduleName = null;
466 if (man != null) {
467 attrs = man.getMainAttributes();
468 if (attrs != null) {
469 moduleName = attrs.getValue(AUTOMATIC_MODULE_NAME);
470 }
471 }
472
473 // Derive the version, and the module name if needed, from JAR file name
474 String fn = jf.getName();
475 int i = fn.lastIndexOf(File.separator);
476 if (i != -1)
477 fn = fn.substring(i + 1);
478
479 // drop ".jar"
480 String name = fn.substring(0, fn.length() - 4);
481 String vs = null;
482
483 // find first occurrence of -${NUMBER}. or -${NUMBER}$
484 Matcher matcher = Patterns.DASH_VERSION.matcher(name);
485 if (matcher.find()) {
486 int start = matcher.start();
487
488 // attempt to parse the tail as a version string
489 try {
490 String tail = name.substring(start + 1);
491 ModuleDescriptor.Version.parse(tail);
492 vs = tail;
493 } catch (IllegalArgumentException ignore) { }
494
495 name = name.substring(0, start);
496 }
497
498 // Create builder, using the name derived from file name when
499 // Automatic-Module-Name not present
500 Builder builder;
501 if (moduleName != null) {
502 try {
503 builder = ModuleDescriptor.newAutomaticModule(moduleName);
504 } catch (IllegalArgumentException e) {
505 throw new FindException(AUTOMATIC_MODULE_NAME + ": " + e.getMessage());
506 }
507 } else {
508 builder = ModuleDescriptor.newAutomaticModule(cleanModuleName(name));
509 }
510
511 // module version if present
512 if (vs != null)
513 builder.version(vs);
514
515 // scan the names of the entries in the JAR file
516 Map<Boolean, Set<String>> map = jf.versionedStream()
517 .filter(e -> !e.isDirectory())
518 .map(JarEntry::getName)
519 .filter(e -> (e.endsWith(".class") ^ e.startsWith(SERVICES_PREFIX)))
520 .collect(Collectors.partitioningBy(e -> e.startsWith(SERVICES_PREFIX),
521 Collectors.toSet()));
522
523 Set<String> classFiles = map.get(Boolean.FALSE);
524 Set<String> configFiles = map.get(Boolean.TRUE);
525
526 // the packages containing class files
527 Set<String> packages = classFiles.stream()
528 .map(this::toPackageName)
529 .flatMap(Optional::stream)
530 .distinct()
531 .collect(Collectors.toSet());
532
533 // all packages are exported and open
534 builder.packages(packages);
535
536 // map names of service configuration files to service names
537 Set<String> serviceNames = configFiles.stream()
538 .map(this::toServiceName)
539 .flatMap(Optional::stream)
540 .collect(Collectors.toSet());
541
542 // parse each service configuration file
543 for (String sn : serviceNames) {
544 JarEntry entry = jf.getJarEntry(SERVICES_PREFIX + sn);
545 List<String> providerClasses = new ArrayList<>();
546 try (InputStream in = jf.getInputStream(entry)) {
547 BufferedReader reader
548 = new BufferedReader(new InputStreamReader(in, "UTF-8"));
549 String cn;
550 while ((cn = nextLine(reader)) != null) {
551 if (cn.length() > 0) {
552 String pn = packageName(cn);
553 if (!packages.contains(pn)) {
554 String msg = "Provider class " + cn + " not in module";
555 throw new InvalidModuleDescriptorException(msg);
556 }
557 providerClasses.add(cn);
558 }
559 }
560 }
561 if (!providerClasses.isEmpty())
562 builder.provides(sn, providerClasses);
563 }
564
565 // Main-Class attribute if it exists
566 if (attrs != null) {
567 String mainClass = attrs.getValue(Attributes.Name.MAIN_CLASS);
568 if (mainClass != null) {
569 mainClass = mainClass.replace("/", ".");
570 if (Checks.isClassName(mainClass)) {
571 String pn = packageName(mainClass);
572 if (packages.contains(pn)) {
573 builder.mainClass(mainClass);
574 }
575 }
576 }
577 }
578
579 return builder.build();
580 }
581
582 /**
583 * Patterns used to derive the module name from a JAR file name.
584 */
585 private static class Patterns {
586 static final Pattern DASH_VERSION = Pattern.compile("-(\\d+(\\.|$))");
587 static final Pattern NON_ALPHANUM = Pattern.compile("[^A-Za-z0-9]");
588 static final Pattern REPEATING_DOTS = Pattern.compile("(\\.)(\\1)+");
589 static final Pattern LEADING_DOTS = Pattern.compile("^\\.");
590 static final Pattern TRAILING_DOTS = Pattern.compile("\\.$");
591 }
592
593 /**
594 * Clean up candidate module name derived from a JAR file name.
595 */
596 private static String cleanModuleName(String mn) {
597 // replace non-alphanumeric
598 mn = Patterns.NON_ALPHANUM.matcher(mn).replaceAll(".");
599
600 // collapse repeating dots
601 mn = Patterns.REPEATING_DOTS.matcher(mn).replaceAll(".");
602
603 // drop leading dots
604 if (mn.length() > 0 && mn.charAt(0) == '.')
605 mn = Patterns.LEADING_DOTS.matcher(mn).replaceAll("");
606
607 // drop trailing dots
608 int len = mn.length();
609 if (len > 0 && mn.charAt(len-1) == '.')
610 mn = Patterns.TRAILING_DOTS.matcher(mn).replaceAll("");
611
612 return mn;
613 }
614
615 private Set<String> jarPackages(JarFile jf) {
616 return jf.versionedStream()
617 .filter(e -> !e.isDirectory())
618 .map(JarEntry::getName)
619 .map(this::toPackageName)
620 .flatMap(Optional::stream)
621 .collect(Collectors.toSet());
622 }
623
624 /**
625 * Returns a {@code ModuleReference} to a module in modular JAR file on
626 * the file system.
627 *
628 * @throws IOException
629 * @throws FindException
630 * @throws InvalidModuleDescriptorException
631 */
632 private ModuleReference readJar(Path file) throws IOException {
633 try (JarFile jf = new JarFile(file.toFile(),
634 true, // verify
635 ZipFile.OPEN_READ,
636 releaseVersion))
637 {
638 ModuleInfo.Attributes attrs;
639 JarEntry entry = jf.getJarEntry(MODULE_INFO);
640 if (entry == null) {
641
642 // no module-info.class so treat it as automatic module
643 try {
644 ModuleDescriptor md = deriveModuleDescriptor(jf);
645 attrs = new ModuleInfo.Attributes(md, null, null, null);
646 } catch (RuntimeException e) {
647 throw new FindException("Unable to derive module descriptor for "
648 + jf.getName(), e);
649 }
650
651 } else {
652 attrs = ModuleInfo.read(jf.getInputStream(entry),
653 () -> jarPackages(jf));
654 }
655
656 return ModuleReferences.newJarModule(attrs, patcher, file);
657 } catch (ZipException e) {
658 throw new FindException("Error reading " + file, e);
659 }
660 }
661
662
663 // -- exploded directories --
664
665 private Set<String> explodedPackages(Path dir) {
666 try {
667 return Files.find(dir, Integer.MAX_VALUE,
668 ((path, attrs) -> attrs.isRegularFile() && !isHidden(path)))
669 .map(path -> dir.relativize(path))
670 .map(this::toPackageName)
671 .flatMap(Optional::stream)
672 .collect(Collectors.toSet());
673 } catch (IOException x) {
674 throw new UncheckedIOException(x);
675 }
676 }
677
678 /**
679 * Returns a {@code ModuleReference} to an exploded module on the file
680 * system or {@code null} if {@code module-info.class} not found.
681 *
682 * @throws IOException
683 * @throws InvalidModuleDescriptorException
684 */
685 private ModuleReference readExplodedModule(Path dir) throws IOException {
686 Path mi = dir.resolve(MODULE_INFO);
687 ModuleInfo.Attributes attrs;
688 try (InputStream in = Files.newInputStream(mi)) {
689 attrs = ModuleInfo.read(new BufferedInputStream(in),
690 () -> explodedPackages(dir));
691 } catch (NoSuchFileException e) {
692 // for now
693 return null;
694 }
695 return ModuleReferences.newExplodedModule(attrs, patcher, dir);
696 }
697
698 /**
699 * Maps a type name to its package name.
700 */
701 private static String packageName(String cn) {
702 int index = cn.lastIndexOf('.');
703 return (index == -1) ? "" : cn.substring(0, index);
704 }
705
706 /**
707 * Maps the name of an entry in a JAR or ZIP file to a package name.
708 *
709 * @throws InvalidModuleDescriptorException if the name is a class file in
710 * the top-level directory of the JAR/ZIP file (and it's not
711 * module-info.class)
712 */
713 private Optional<String> toPackageName(String name) {
714 assert !name.endsWith("/");
715 int index = name.lastIndexOf("/");
716 if (index == -1) {
717 if (name.endsWith(".class") && !name.equals(MODULE_INFO)) {
718 String msg = name + " found in top-level directory"
719 + " (unnamed package not allowed in module)";
720 throw new InvalidModuleDescriptorException(msg);
721 }
722 return Optional.empty();
723 }
724
725 String pn = name.substring(0, index).replace('/', '.');
726 if (Checks.isPackageName(pn)) {
727 return Optional.of(pn);
728 } else {
729 // not a valid package name
730 return Optional.empty();
731 }
732 }
733
734 /**
735 * Maps the relative path of an entry in an exploded module to a package
736 * name.
737 *
738 * @throws InvalidModuleDescriptorException if the name is a class file in
739 * the top-level directory (and it's not module-info.class)
740 */
741 private Optional<String> toPackageName(Path file) {
742 assert file.getRoot() == null;
743
744 Path parent = file.getParent();
745 if (parent == null) {
746 String name = file.toString();
747 if (name.endsWith(".class") && !name.equals(MODULE_INFO)) {
748 String msg = name + " found in top-level directory"
749 + " (unnamed package not allowed in module)";
750 throw new InvalidModuleDescriptorException(msg);
751 }
752 return Optional.empty();
753 }
754
755 String pn = parent.toString().replace(File.separatorChar, '.');
756 if (Checks.isPackageName(pn)) {
757 return Optional.of(pn);
758 } else {
759 // not a valid package name
760 return Optional.empty();
761 }
762 }
763
764 /**
765 * Returns true if the given file exists and is a hidden file
766 */
767 private boolean isHidden(Path file) {
768 try {
769 return Files.isHidden(file);
770 } catch (IOException ioe) {
771 return false;
772 }
773 }
774
775
776 /**
777 * Return true if a path locates a path in the default file system
778 */
779 private boolean isDefaultFileSystem(Path path) {
780 return path.getFileSystem().provider()
781 .getScheme().equalsIgnoreCase("file");
782 }
783
784
785 private static final PerfCounter scanTime
786 = PerfCounter.newPerfCounter("jdk.module.finder.modulepath.scanTime");
787 private static final PerfCounter moduleCount
788 = PerfCounter.newPerfCounter("jdk.module.finder.modulepath.modules");
789 }