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 import jdk.internal.util.jar.VersionedStream;

    70 

    71 

    72 /**

    73  * A {@code ModuleFinder} that locates modules on the file system by searching

    74  * a sequence of directories or packaged modules. The ModuleFinder can be

    75  * created to work in either the run-time or link-time phases. In both cases it

    76  * locates modular JAR and exploded modules. When created for link-time then it

    77  * additionally locates modules in JMOD files. The ModuleFinder can also

    78  * optionally patch any modules that it locates with a ModulePatcher.

    79  */

    80 

    81 public class ModulePath implements ModuleFinder {

    82     private static final String MODULE_INFO = "module-info.class";

    83 

    84     // the version to use for multi-release modular JARs

    85     private final Runtime.Version releaseVersion;

    86 

    87     // true for the link phase (supports modules packaged in JMOD format)

    88     private final boolean isLinkPhase;

    89 

    90     // for patching modules, can be null

    91     private final ModulePatcher patcher;

    92 

    93     // the entries on this module path

    94     private final Path[] entries;

    95     private int next;

    96 

    97     // map of module name to module reference map for modules already located

    98     private final Map<String, ModuleReference> cachedModules = new HashMap<>();

    99 

   100 

   101     private ModulePath(Runtime.Version version,

   102                        boolean isLinkPhase,

   103                        ModulePatcher patcher,

   104                        Path... entries) {

   105         this.releaseVersion = version;

   106         this.isLinkPhase = isLinkPhase;

   107         this.patcher = patcher;

   108         this.entries = entries.clone();

   109         for (Path entry : this.entries) {

   110             Objects.requireNonNull(entry);

   111         }

   112     }

   113 

   114     /**

   115      * Returns a ModuleFinder that that locates modules on the file system by

   116      * searching a sequence of directories and/or packaged modules. The modules

   117      * may be patched by the given ModulePatcher.

   118      */

   119     public static ModuleFinder of(ModulePatcher patcher, Path... entries) {

   120         return new ModulePath(JarFile.runtimeVersion(), false, patcher, entries);

   121     }

   122 

   123     /**

   124      * Returns a ModuleFinder that that locates modules on the file system by

   125      * searching a sequence of directories and/or packaged modules.

   126      */

   127     public static ModuleFinder of(Path... entries) {

   128         return of((ModulePatcher)null, entries);

   129     }

   130 

   131     /**

   132      * Returns a ModuleFinder that that locates modules on the file system by

   133      * searching a sequence of directories and/or packaged modules.

   134      *

   135      * @param version The release version to use for multi-release JAR files

   136      * @param isLinkPhase {@code true} if the link phase to locate JMOD files

   137      */

   138     public static ModuleFinder of(Runtime.Version version,

   139                                   boolean isLinkPhase,

   140                                   Path... entries) {

   141         return new ModulePath(version, isLinkPhase, null, entries);

   142     }

   143 

   144 

   145     @Override

   146     public Optional<ModuleReference> find(String name) {

   147         Objects.requireNonNull(name);

   148 

   149         // try cached modules

   150         ModuleReference m = cachedModules.get(name);

   151         if (m != null)

   152             return Optional.of(m);

   153 

   154         // the module may not have been encountered yet

   155         while (hasNextEntry()) {

   156             scanNextEntry();

   157             m = cachedModules.get(name);

   158             if (m != null)

   159                 return Optional.of(m);

   160         }

   161         return Optional.empty();

   162     }

   163 

   164     @Override

   165     public Set<ModuleReference> findAll() {

   166         // need to ensure that all entries have been scanned

   167         while (hasNextEntry()) {

   168             scanNextEntry();

   169         }

   170         return cachedModules.values().stream().collect(Collectors.toSet());

   171     }

   172 

   173     /**

   174      * Returns {@code true} if there are additional entries to scan

   175      */

   176     private boolean hasNextEntry() {

   177         return next < entries.length;

   178     }

   179 

   180     /**

   181      * Scans the next entry on the module path. A no-op if all entries have

   182      * already been scanned.

   183      *

   184      * @throws FindException if an error occurs scanning the next entry

   185      */

   186     private void scanNextEntry() {

   187         if (hasNextEntry()) {

   188 

   189             long t0 = System.nanoTime();

   190 

   191             Path entry = entries[next];

   192             Map<String, ModuleReference> modules = scan(entry);

   193             next++;

   194 

   195             // update cache, ignoring duplicates

   196             int initialSize = cachedModules.size();

   197             for (Map.Entry<String, ModuleReference> e : modules.entrySet()) {

   198                 cachedModules.putIfAbsent(e.getKey(), e.getValue());

   199             }

   200 

   201             // update counters

   202             int added = cachedModules.size() - initialSize;

   203             moduleCount.add(added);

   204 

   205             scanTime.addElapsedTimeFrom(t0);

   206         }

   207     }

   208 

   209 

   210     /**

   211      * Scan the given module path entry. If the entry is a directory then it is

   212      * a directory of modules or an exploded module. If the entry is a regular

   213      * file then it is assumed to be a packaged module.

   214      *

   215      * @throws FindException if an error occurs scanning the entry

   216      */

   217     private Map<String, ModuleReference> scan(Path entry) {

   218 

   219         BasicFileAttributes attrs;

   220         try {

   221             attrs = Files.readAttributes(entry, BasicFileAttributes.class);

   222         } catch (NoSuchFileException e) {

   223             return Collections.emptyMap();

   224         } catch (IOException ioe) {

   225             throw new FindException(ioe);

   226         }

   227 

   228         try {

   229 

   230             if (attrs.isDirectory()) {

   231                 Path mi = entry.resolve(MODULE_INFO);

   232                 if (!Files.exists(mi)) {

   233                     // assume a directory of modules

   234                     return scanDirectory(entry);

   235                 }

   236             }

   237 

   238             // packaged or exploded module

   239             ModuleReference mref = readModule(entry, attrs);

   240             if (mref != null) {

   241                 String name = mref.descriptor().name();

   242                 return Collections.singletonMap(name, mref);

   243             }

   244 

   245             // not recognized

   246             String msg;

   247             if (!isLinkPhase && entry.toString().endsWith(".jmod")) {

   248                 msg = "JMOD format not supported at execution time";

   249             } else {

   250                 msg = "Module format not recognized";

   251             }

   252             throw new FindException(msg + ": " + entry);

   253 

   254         } catch (IOException ioe) {

   255             throw new FindException(ioe);

   256         }

   257     }

   258 

   259 

   260     /**

   261      * Scans the given directory for packaged or exploded modules.

   262      *

   263      * @return a map of module name to ModuleReference for the modules found

   264      *         in the directory

   265      *

   266      * @throws IOException if an I/O error occurs

   267      * @throws FindException if an error occurs scanning the entry or the

   268      *         directory contains two or more modules with the same name

   269      */

   270     private Map<String, ModuleReference> scanDirectory(Path dir)

   271         throws IOException

   272     {

   273         // The map of name -> mref of modules found in this directory.

   274         Map<String, ModuleReference> nameToReference = new HashMap<>();

   275 

   276         try (DirectoryStream<Path> stream = Files.newDirectoryStream(dir)) {

   277             for (Path entry : stream) {

   278                 BasicFileAttributes attrs;

   279                 try {

   280                     attrs = Files.readAttributes(entry, BasicFileAttributes.class);

   281                 } catch (NoSuchFileException ignore) {

   282                     // file has been removed or moved, ignore for now

   283                     continue;

   284                 }

   285 

   286                 ModuleReference mref = readModule(entry, attrs);

   287 

   288                 // module found

   289                 if (mref != null) {

   290                     // can have at most one version of a module in the directory

   291                     String name = mref.descriptor().name();

   292                     ModuleReference previous = nameToReference.put(name, mref);

   293                     if (previous != null) {

   294                         String fn1 = fileName(mref);

   295                         String fn2 = fileName(previous);

   296                         throw new FindException("Two versions of module "

   297                                                  + name + " found in " + dir

   298                                                  + " (" + fn1 + " and " + fn2 + ")");

   299                     }

   300                 }

   301             }

   302         }

   303 

   304         return nameToReference;

   305     }

   306 

   307 

   308     /**

   309      * Reads a packaged or exploded module, returning a {@code ModuleReference}

   310      * to the module. Returns {@code null} if the entry is not recognized.

   311      *

   312      * @throws IOException if an I/O error occurs

   313      * @throws FindException if an error occurs parsing its module descriptor

   314      */

   315     private ModuleReference readModule(Path entry, BasicFileAttributes attrs)

   316         throws IOException

   317     {

   318         try {

   319 

   320             // exploded module

   321             if (attrs.isDirectory()) {

   322                 return readExplodedModule(entry); // may return null

   323             }

   324 

   325             // JAR or JMOD file

   326             if (attrs.isRegularFile()) {

   327                 String fn = entry.getFileName().toString();

   328                 boolean isDefaultFileSystem = isDefaultFileSystem(entry);

   329 

   330                 // JAR file

   331                 if (fn.endsWith(".jar")) {

   332                     if (isDefaultFileSystem) {

   333                         return readJar(entry);

   334                     } else {

   335                         // the JAR file is in a custom file system so

   336                         // need to copy it to the local file system

   337                         Path tmpdir = Files.createTempDirectory("mlib");

   338                         Path target = Files.copy(entry, tmpdir.resolve(fn));

   339                         return readJar(target);

   340                     }

   341                 }

   342 

   343                 // JMOD file

   344                 if (isDefaultFileSystem && isLinkPhase && fn.endsWith(".jmod")) {

   345                     return readJMod(entry);

   346                 }

   347             }

   348 

   349             return null;

   350 

   351         } catch (InvalidModuleDescriptorException e) {

   352             throw new FindException("Error reading module: " + entry, e);

   353         }

   354     }

   355 

   356     /**

   357      * Returns a string with the file name of the module if possible.

   358      * If the module location is not a file URI then return the URI

   359      * as a string.

   360      */

   361     private String fileName(ModuleReference mref) {

   362         URI uri = mref.location().orElse(null);

   363         if (uri != null) {

   364             if (uri.getScheme().equalsIgnoreCase("file")) {

   365                 Path file = Paths.get(uri);

   366                 return file.getFileName().toString();

   367             } else {

   368                 return uri.toString();

   369             }

   370         } else {

   371             return "<unknown>";

   372         }

   373     }

   374 

   375     // -- JMOD files --

   376 

   377     private Set<String> jmodPackages(JmodFile jf) {

   378         return jf.stream()

   379             .filter(e -> e.section() == Section.CLASSES)

   380             .map(JmodFile.Entry::name)

   381             .map(this::toPackageName)

   382             .flatMap(Optional::stream)

   383             .collect(Collectors.toSet());

   384     }

   385 

   386     /**

   387      * Returns a {@code ModuleReference} to a module in JMOD file on the

   388      * file system.

   389      *

   390      * @throws IOException

   391      * @throws InvalidModuleDescriptorException

   392      */

   393     private ModuleReference readJMod(Path file) throws IOException {

   394         try (JmodFile jf = new JmodFile(file)) {

   395             ModuleInfo.Attributes attrs;

   396             try (InputStream in = jf.getInputStream(Section.CLASSES, MODULE_INFO)) {

   397                 attrs  = ModuleInfo.read(in, () -> jmodPackages(jf));

   398             }

   399             return ModuleReferences.newJModModule(attrs, file);

   400         }

   401     }

   402 

   403 

   404     // -- JAR files --

   405 

   406     private static final String SERVICES_PREFIX = "META-INF/services/";

   407 

   408     private static final Attributes.Name AUTOMATIC_MODULE_NAME

   409         = new Attributes.Name("Automatic-Module-Name");

   410 

   411     /**

   412      * Returns the service type corresponding to the name of a services

   413      * configuration file if it is a legal type name.

   414      *

   415      * For example, if called with "META-INF/services/p.S" then this method

   416      * returns a container with the value "p.S".

   417      */

   418     private Optional<String> toServiceName(String cf) {

   419         assert cf.startsWith(SERVICES_PREFIX);

   420         int index = cf.lastIndexOf("/") + 1;

   421         if (index < cf.length()) {

   422             String prefix = cf.substring(0, index);

   423             if (prefix.equals(SERVICES_PREFIX)) {

   424                 String sn = cf.substring(index);

   425                 if (Checks.isClassName(sn))

   426                     return Optional.of(sn);

   427             }

   428         }

   429         return Optional.empty();

   430     }

   431 

   432     /**

   433      * Reads the next line from the given reader and trims it of comments and

   434      * leading/trailing white space.

   435      *

   436      * Returns null if the reader is at EOF.

   437      */

   438     private String nextLine(BufferedReader reader) throws IOException {

   439         String ln = reader.readLine();

   440         if (ln != null) {

   441             int ci = ln.indexOf('#');

   442             if (ci >= 0)

   443                 ln = ln.substring(0, ci);

   444             ln = ln.trim();

   445         }

   446         return ln;

   447     }

   448 

   449     /**

   450      * Treat the given JAR file as a module as follows:

   451      *

   452      * 1. The value of the Automatic-Module-Name attribute is the module name

   453      * 2. The version, and the module name when the  Automatic-Module-Name

   454      *    attribute is not present, is derived from the file ame of the JAR file

   455      * 3. All packages are derived from the .class files in the JAR file

   456      * 4. The contents of any META-INF/services configuration files are mapped

   457      *    to "provides" declarations

   458      * 5. The Main-Class attribute in the main attributes of the JAR manifest

   459      *    is mapped to the module descriptor mainClass if possible

   460      */

   461     private ModuleDescriptor deriveModuleDescriptor(JarFile jf)

   462         throws IOException

   463     {

   464         // Read Automatic-Module-Name attribute if present

   465         Manifest man = jf.getManifest();

   466         Attributes attrs = null;

   467         String moduleName = null;

   468         if (man != null) {

   469             attrs = man.getMainAttributes();

   470             if (attrs != null) {

   471                 moduleName = attrs.getValue(AUTOMATIC_MODULE_NAME);

   472             }

   473         }

   474 

   475         // Derive the version, and the module name if needed, from JAR file name

   476         String fn = jf.getName();

   477         int i = fn.lastIndexOf(File.separator);

   478         if (i != -1)

   479             fn = fn.substring(i + 1);

   480 

   481         // drop ".jar"

   482         String name = fn.substring(0, fn.length() - 4);

   483         String vs = null;

   484 

   485         // find first occurrence of -${NUMBER}. or -${NUMBER}$

   486         Matcher matcher = Patterns.DASH_VERSION.matcher(name);

   487         if (matcher.find()) {

   488             int start = matcher.start();

   489 

   490             // attempt to parse the tail as a version string

   491             try {

   492                 String tail = name.substring(start + 1);

   493                 ModuleDescriptor.Version.parse(tail);

   494                 vs = tail;

   495             } catch (IllegalArgumentException ignore) { }

   496 

   497             name = name.substring(0, start);

   498         }

   499 

   500         // Create builder, using the name derived from file name when

   501         // Automatic-Module-Name not present

   502         Builder builder;

   503         if (moduleName != null) {

   504             try {

   505                 builder = ModuleDescriptor.newAutomaticModule(moduleName);

   506             } catch (IllegalArgumentException e) {

   507                 throw new FindException(AUTOMATIC_MODULE_NAME + ": " + e.getMessage());

   508             }

   509         } else {

   510             builder = ModuleDescriptor.newAutomaticModule(cleanModuleName(name));

   511         }

   512 

   513         // module version if present

   514         if (vs != null)

   515             builder.version(vs);

   516 

   517         // scan the names of the entries in the JAR file

   518         Map<Boolean, Set<String>> map = VersionedStream.stream(jf)

   519                 .filter(e -> !e.isDirectory())

   520                 .map(JarEntry::getName)

   521                 .filter(e -> (e.endsWith(".class") ^ e.startsWith(SERVICES_PREFIX)))

   522                 .collect(Collectors.partitioningBy(e -> e.startsWith(SERVICES_PREFIX),

   523                                                    Collectors.toSet()));

   524 

   525         Set<String> classFiles = map.get(Boolean.FALSE);

   526         Set<String> configFiles = map.get(Boolean.TRUE);

   527 

   528         // the packages containing class files

   529         Set<String> packages = classFiles.stream()

   530                 .map(this::toPackageName)

   531                 .flatMap(Optional::stream)

   532                 .distinct()

   533                 .collect(Collectors.toSet());

   534 

   535         // all packages are exported and open

   536         builder.packages(packages);

   537 

   538         // map names of service configuration files to service names

   539         Set<String> serviceNames = configFiles.stream()

   540                 .map(this::toServiceName)

   541                 .flatMap(Optional::stream)

   542                 .collect(Collectors.toSet());

   543 

   544         // parse each service configuration file

   545         for (String sn : serviceNames) {

   546             JarEntry entry = jf.getJarEntry(SERVICES_PREFIX + sn);

   547             List<String> providerClasses = new ArrayList<>();

   548             try (InputStream in = jf.getInputStream(entry)) {

   549                 BufferedReader reader

   550                     = new BufferedReader(new InputStreamReader(in, "UTF-8"));

   551                 String cn;

   552                 while ((cn = nextLine(reader)) != null) {

   553                     if (cn.length() > 0) {

   554                         String pn = packageName(cn);

   555                         if (!packages.contains(pn)) {

   556                             String msg = "Provider class " + cn + " not in module";

   557                             throw new InvalidModuleDescriptorException(msg);

   558                         }

   559                         providerClasses.add(cn);

   560                     }

   561                 }

   562             }

   563             if (!providerClasses.isEmpty())

   564                 builder.provides(sn, providerClasses);

   565         }

   566 

   567         // Main-Class attribute if it exists

   568         if (attrs != null) {

   569             String mainClass = attrs.getValue(Attributes.Name.MAIN_CLASS);

   570             if (mainClass != null) {

   571                 mainClass = mainClass.replace("/", ".");

   572                 if (Checks.isClassName(mainClass)) {

   573                     String pn = packageName(mainClass);

   574                     if (packages.contains(pn)) {

   575                         builder.mainClass(mainClass);

   576                     }

   577                 }

   578             }

   579         }

   580 

   581         return builder.build();

   582     }

   583 

   584     /**

   585      * Patterns used to derive the module name from a JAR file name.

   586      */

   587     private static class Patterns {

   588         static final Pattern DASH_VERSION = Pattern.compile("-(\\d+(\\.|$))");

   589         static final Pattern NON_ALPHANUM = Pattern.compile("[^A-Za-z0-9]");

   590         static final Pattern REPEATING_DOTS = Pattern.compile("(\\.)(\\1)+");

   591         static final Pattern LEADING_DOTS = Pattern.compile("^\\.");

   592         static final Pattern TRAILING_DOTS = Pattern.compile("\\.$");

   593     }

   594 

   595     /**

   596      * Clean up candidate module name derived from a JAR file name.

   597      */

   598     private static String cleanModuleName(String mn) {

   599         // replace non-alphanumeric

   600         mn = Patterns.NON_ALPHANUM.matcher(mn).replaceAll(".");

   601 

   602         // collapse repeating dots

   603         mn = Patterns.REPEATING_DOTS.matcher(mn).replaceAll(".");

   604 

   605         // drop leading dots

   606         if (mn.length() > 0 && mn.charAt(0) == '.')

   607             mn = Patterns.LEADING_DOTS.matcher(mn).replaceAll("");

   608 

   609         // drop trailing dots

   610         int len = mn.length();

   611         if (len > 0 && mn.charAt(len-1) == '.')

   612             mn = Patterns.TRAILING_DOTS.matcher(mn).replaceAll("");

   613 

   614         return mn;

   615     }

   616 

   617     private Set<String> jarPackages(JarFile jf) {

   618         return VersionedStream.stream(jf)

   619                 .filter(e -> !e.isDirectory())

   620                 .map(JarEntry::getName)

   621                 .map(this::toPackageName)

   622                 .flatMap(Optional::stream)

   623                 .collect(Collectors.toSet());

   624     }

   625 

   626     /**

   627      * Returns a {@code ModuleReference} to a module in modular JAR file on

   628      * the file system.

   629      *

   630      * @throws IOException

   631      * @throws FindException

   632      * @throws InvalidModuleDescriptorException

   633      */

   634     private ModuleReference readJar(Path file) throws IOException {

   635         try (JarFile jf = new JarFile(file.toFile(),

   636                                       true,               // verify

   637                                       ZipFile.OPEN_READ,

   638                                       releaseVersion))

   639         {

   640             ModuleInfo.Attributes attrs;

   641             JarEntry entry = jf.getJarEntry(MODULE_INFO);

   642             if (entry == null) {

   643 

   644                 // no module-info.class so treat it as automatic module

   645                 try {

   646                     ModuleDescriptor md = deriveModuleDescriptor(jf);

   647                     attrs = new ModuleInfo.Attributes(md, null, null, null);

   648                 } catch (RuntimeException e) {

   649                     throw new FindException("Unable to derive module descriptor for "

   650                                             + jf.getName(), e);

   651                 }

   652 

   653             } else {

   654                 attrs = ModuleInfo.read(jf.getInputStream(entry),

   655                                         () -> jarPackages(jf));

   656             }

   657 

   658             return ModuleReferences.newJarModule(attrs, patcher, file);

   659         } catch (ZipException e) {

   660             throw new FindException("Error reading " + file, e);

   661         }

   662     }

   663 

   664 

   665     // -- exploded directories --

   666 

   667     private Set<String> explodedPackages(Path dir) {

   668         try {

   669             return Files.find(dir, Integer.MAX_VALUE,

   670                     ((path, attrs) -> attrs.isRegularFile() && !isHidden(path)))

   671                     .map(path -> dir.relativize(path))

   672                     .map(this::toPackageName)

   673                     .flatMap(Optional::stream)

   674                     .collect(Collectors.toSet());

   675         } catch (IOException x) {

   676             throw new UncheckedIOException(x);

   677         }

   678     }

   679 

   680     /**

   681      * Returns a {@code ModuleReference} to an exploded module on the file

   682      * system or {@code null} if {@code module-info.class} not found.

   683      *

   684      * @throws IOException

   685      * @throws InvalidModuleDescriptorException

   686      */

   687     private ModuleReference readExplodedModule(Path dir) throws IOException {

   688         Path mi = dir.resolve(MODULE_INFO);

   689         ModuleInfo.Attributes attrs;

   690         try (InputStream in = Files.newInputStream(mi)) {

   691             attrs = ModuleInfo.read(new BufferedInputStream(in),

   692                                     () -> explodedPackages(dir));

   693         } catch (NoSuchFileException e) {

   694             // for now

   695             return null;

   696         }

   697         return ModuleReferences.newExplodedModule(attrs, patcher, dir);

   698     }

   699 

   700     /**

   701      * Maps a type name to its package name.

   702      */

   703     private static String packageName(String cn) {

   704         int index = cn.lastIndexOf('.');

   705         return (index == -1) ? "" : cn.substring(0, index);

   706     }

   707 

   708     /**

   709      * Maps the name of an entry in a JAR or ZIP file to a package name.

   710      *

   711      * @throws InvalidModuleDescriptorException if the name is a class file in

   712      *         the top-level directory of the JAR/ZIP file (and it's not

   713      *         module-info.class)

   714      */

   715     private Optional<String> toPackageName(String name) {

   716         assert !name.endsWith("/");

   717         int index = name.lastIndexOf("/");

   718         if (index == -1) {

   719             if (name.endsWith(".class") && !name.equals(MODULE_INFO)) {

   720                 String msg = name + " found in top-level directory"

   721                              + " (unnamed package not allowed in module)";

   722                 throw new InvalidModuleDescriptorException(msg);

   723             }

   724             return Optional.empty();

   725         }

   726 

   727         String pn = name.substring(0, index).replace('/', '.');

   728         if (Checks.isPackageName(pn)) {

   729             return Optional.of(pn);

   730         } else {

   731             // not a valid package name

   732             return Optional.empty();

   733         }

   734     }

   735 

   736     /**

   737      * Maps the relative path of an entry in an exploded module to a package

   738      * name.

   739      *

   740      * @throws InvalidModuleDescriptorException if the name is a class file in

   741      *         the top-level directory (and it's not module-info.class)

   742      */

   743     private Optional<String> toPackageName(Path file) {

   744         assert file.getRoot() == null;

   745 

   746         Path parent = file.getParent();

   747         if (parent == null) {

   748             String name = file.toString();

   749             if (name.endsWith(".class") && !name.equals(MODULE_INFO)) {

   750                 String msg = name + " found in top-level directory"

   751                              + " (unnamed package not allowed in module)";

   752                 throw new InvalidModuleDescriptorException(msg);

   753             }

   754             return Optional.empty();

   755         }

   756 

   757         String pn = parent.toString().replace(File.separatorChar, '.');

   758         if (Checks.isPackageName(pn)) {

   759             return Optional.of(pn);

   760         } else {

   761             // not a valid package name

   762             return Optional.empty();

   763         }

   764     }

   765 

   766     /**

   767      * Returns true if the given file exists and is a hidden file

   768      */

   769     private boolean isHidden(Path file) {

   770         try {

   771             return Files.isHidden(file);

   772         } catch (IOException ioe) {

   773             return false;

   774         }

   775     }

   776 

   777 

   778     /**

   779      * Return true if a path locates a path in the default file system

   780      */

   781     private boolean isDefaultFileSystem(Path path) {

   782         return path.getFileSystem().provider()

   783                 .getScheme().equalsIgnoreCase("file");

   784     }

   785 

   786 

   787     private static final PerfCounter scanTime

   788         = PerfCounter.newPerfCounter("jdk.module.finder.modulepath.scanTime");

   789     private static final PerfCounter moduleCount

   790         = PerfCounter.newPerfCounter("jdk.module.finder.modulepath.modules");

   791 }