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 java.lang;

    27 

    28 import java.io.IOException;

    29 import java.io.InputStream;

    30 import java.lang.annotation.Annotation;

    31 import java.lang.module.Configuration;

    32 import java.lang.module.ModuleReference;

    33 import java.lang.module.ModuleDescriptor;

    34 import java.lang.module.ModuleDescriptor.Exports;

    35 import java.lang.module.ModuleDescriptor.Opens;

    36 import java.lang.module.ModuleDescriptor.Version;

    37 import java.lang.module.ResolvedModule;

    38 import java.lang.reflect.AnnotatedElement;

    39 import java.net.URI;

    40 import java.net.URL;

    41 import java.security.AccessController;

    42 import java.security.PrivilegedAction;

    43 import java.util.Collections;

    44 import java.util.HashMap;

    45 import java.util.HashSet;

    46 import java.util.List;

    47 import java.util.Map;

    48 import java.util.Objects;

    49 import java.util.Optional;

    50 import java.util.Set;

    51 import java.util.concurrent.ConcurrentHashMap;

    52 import java.util.function.Function;

    53 import java.util.stream.Collectors;

    54 import java.util.stream.Stream;

    55 

    56 import jdk.internal.loader.BuiltinClassLoader;

    57 import jdk.internal.loader.BootLoader;

    58 import jdk.internal.misc.JavaLangAccess;

    59 import jdk.internal.misc.SharedSecrets;

    60 import jdk.internal.module.ServicesCatalog;

    61 import jdk.internal.module.Resources;

    62 import jdk.internal.org.objectweb.asm.AnnotationVisitor;

    63 import jdk.internal.org.objectweb.asm.Attribute;

    64 import jdk.internal.org.objectweb.asm.ClassReader;

    65 import jdk.internal.org.objectweb.asm.ClassVisitor;

    66 import jdk.internal.org.objectweb.asm.ClassWriter;

    67 import jdk.internal.org.objectweb.asm.Opcodes;

    68 import jdk.internal.reflect.CallerSensitive;

    69 import jdk.internal.reflect.Reflection;

    70 import sun.security.util.SecurityConstants;

    71 

    72 /**

    73  * Represents a run-time module, either {@link #isNamed() named} or unnamed.

    74  *

    75  * <p> Named modules have a {@link #getName() name} and are constructed by the

    76  * Java Virtual Machine when a graph of modules is defined to the Java virtual

    77  * machine to create a {@linkplain ModuleLayer module layer}. </p>

    78  *

    79  * <p> An unnamed module does not have a name. There is an unnamed module for

    80  * each {@link ClassLoader ClassLoader}, obtained by invoking its {@link

    81  * ClassLoader#getUnnamedModule() getUnnamedModule} method. All types that are

    82  * not in a named module are members of their defining class loader's unnamed

    83  * module. </p>

    84  *

    85  * <p> The package names that are parameters or returned by methods defined in

    86  * this class are the fully-qualified names of the packages as defined in

    87  * section 6.5.3 of <cite>The Java&trade; Language Specification</cite>, for

    88  * example, {@code "java.lang"}. </p>

    89  *

    90  * <p> Unless otherwise specified, passing a {@code null} argument to a method

    91  * in this class causes a {@link NullPointerException NullPointerException} to

    92  * be thrown. </p>

    93  *

    94  * @since 9

    95  * @spec JPMS

    96  * @see Class#getModule()

    97  */

    98 

    99 public final class Module implements AnnotatedElement {

   100 

   101     // the layer that contains this module, can be null

   102     private final ModuleLayer layer;

   103 

   104     // module name and loader, these fields are read by VM

   105     private final String name;

   106     private final ClassLoader loader;

   107 

   108     // the module descriptor

   109     private final ModuleDescriptor descriptor;

   110 

   111 

   112     /**

   113      * Creates a new named Module. The resulting Module will be defined to the

   114      * VM but will not read any other modules, will not have any exports setup

   115      * and will not be registered in the service catalog.

   116      */

   117     Module(ModuleLayer layer,

   118            ClassLoader loader,

   119            ModuleDescriptor descriptor,

   120            URI uri)

   121     {

   122         this.layer = layer;

   123         this.name = descriptor.name();

   124         this.loader = loader;

   125         this.descriptor = descriptor;

   126 

   127         // define module to VM

   128 

   129         boolean isOpen = descriptor.isOpen();

   130         Version version = descriptor.version().orElse(null);

   131         String vs = Objects.toString(version, null);

   132         String loc = Objects.toString(uri, null);

   133         String[] packages = descriptor.packages().toArray(new String[0]);

   134         defineModule0(this, isOpen, vs, loc, packages);

   135     }

   136 

   137 

   138     /**

   139      * Create the unnamed Module for the given ClassLoader.

   140      *

   141      * @see ClassLoader#getUnnamedModule

   142      */

   143     Module(ClassLoader loader) {

   144         this.layer = null;

   145         this.name = null;

   146         this.loader = loader;

   147         this.descriptor = null;

   148     }

   149 

   150 

   151     /**

   152      * Creates a named module but without defining the module to the VM.

   153      *

   154      * @apiNote This constructor is for VM white-box testing.

   155      */

   156     Module(ClassLoader loader, ModuleDescriptor descriptor) {

   157         this.layer = null;

   158         this.name = descriptor.name();

   159         this.loader = loader;

   160         this.descriptor = descriptor;

   161     }

   162 

   163 

   164 

   165     /**

   166      * Returns {@code true} if this module is a named module.

   167      *

   168      * @return {@code true} if this is a named module

   169      *

   170      * @see ClassLoader#getUnnamedModule()

   171      */

   172     public boolean isNamed() {

   173         return name != null;

   174     }

   175 

   176     /**

   177      * Returns the module name or {@code null} if this module is an unnamed

   178      * module.

   179      *

   180      * @return The module name

   181      */

   182     public String getName() {

   183         return name;

   184     }

   185 

   186     /**

   187      * Returns the {@code ClassLoader} for this module.

   188      *

   189      * <p> If there is a security manager then its {@code checkPermission}

   190      * method if first called with a {@code RuntimePermission("getClassLoader")}

   191      * permission to check that the caller is allowed to get access to the

   192      * class loader. </p>

   193      *

   194      * @return The class loader for this module

   195      *

   196      * @throws SecurityException

   197      *         If denied by the security manager

   198      */

   199     public ClassLoader getClassLoader() {

   200         SecurityManager sm = System.getSecurityManager();

   201         if (sm != null) {

   202             sm.checkPermission(SecurityConstants.GET_CLASSLOADER_PERMISSION);

   203         }

   204         return loader;

   205     }

   206 

   207     /**

   208      * Returns the module descriptor for this module or {@code null} if this

   209      * module is an unnamed module.

   210      *

   211      * @return The module descriptor for this module

   212      */

   213     public ModuleDescriptor getDescriptor() {

   214         return descriptor;

   215     }

   216 

   217     /**

   218      * Returns the layer that contains this module or {@code null} if this

   219      * module is not in a layer.

   220      *

   221      * A module layer contains named modules and therefore this method always

   222      * returns {@code null} when invoked on an unnamed module.

   223      *

   224      * <p> <a href="reflect/Proxy.html#dynamicmodule">Dynamic modules</a> are

   225      * named modules that are generated at runtime. A dynamic module may or may

   226      * not be in a module layer. </p>

   227      *

   228      * @return The module layer that contains this module

   229      *

   230      * @see java.lang.reflect.Proxy

   231      */

   232     public ModuleLayer getLayer() {

   233         if (isNamed()) {

   234             ModuleLayer layer = this.layer;

   235             if (layer != null)

   236                 return layer;

   237 

   238             // special-case java.base as it is created before the boot layer

   239             if (loader == null && name.equals("java.base")) {

   240                 return ModuleLayer.boot();

   241             }

   242         }

   243         return null;

   244     }

   245 

   246 

   247     // --

   248 

   249     // special Module to mean "all unnamed modules"

   250     private static final Module ALL_UNNAMED_MODULE = new Module(null);

   251 

   252     // special Module to mean "everyone"

   253     private static final Module EVERYONE_MODULE = new Module(null);

   254 

   255     // set contains EVERYONE_MODULE, used when a package is opened or

   256     // exported unconditionally

   257     private static final Set<Module> EVERYONE_SET = Set.of(EVERYONE_MODULE);

   258 

   259 

   260     // -- readability --

   261 

   262     // the modules that this module reads

   263     private volatile Set<Module> reads;

   264 

   265     // additional module (2nd key) that some module (1st key) reflectively reads

   266     private static final WeakPairMap<Module, Module, Boolean> reflectivelyReads

   267         = new WeakPairMap<>();

   268 

   269 

   270     /**

   271      * Indicates if this module reads the given module. This method returns

   272      * {@code true} if invoked to test if this module reads itself. It also

   273      * returns {@code true} if invoked on an unnamed module (as unnamed

   274      * modules read all modules).

   275      *

   276      * @param  other

   277      *         The other module

   278      *

   279      * @return {@code true} if this module reads {@code other}

   280      *

   281      * @see #addReads(Module)

   282      */

   283     public boolean canRead(Module other) {

   284         Objects.requireNonNull(other);

   285 

   286         // an unnamed module reads all modules

   287         if (!this.isNamed())

   288             return true;

   289 

   290         // all modules read themselves

   291         if (other == this)

   292             return true;

   293 

   294         // check if this module reads other

   295         if (other.isNamed()) {

   296             Set<Module> reads = this.reads; // volatile read

   297             if (reads != null && reads.contains(other))

   298                 return true;

   299         }

   300 

   301         // check if this module reads the other module reflectively

   302         if (reflectivelyReads.containsKeyPair(this, other))

   303             return true;

   304 

   305         // if other is an unnamed module then check if this module reads

   306         // all unnamed modules

   307         if (!other.isNamed()

   308             && reflectivelyReads.containsKeyPair(this, ALL_UNNAMED_MODULE))

   309             return true;

   310 

   311         return false;

   312     }

   313 

   314     /**

   315      * If the caller's module is this module then update this module to read

   316      * the given module.

   317      *

   318      * This method is a no-op if {@code other} is this module (all modules read

   319      * themselves), this module is an unnamed module (as unnamed modules read

   320      * all modules), or this module already reads {@code other}.

   321      *

   322      * @implNote <em>Read edges</em> added by this method are <em>weak</em> and

   323      * do not prevent {@code other} from being GC'ed when this module is

   324      * strongly reachable.

   325      *

   326      * @param  other

   327      *         The other module

   328      *

   329      * @return this module

   330      *

   331      * @throws IllegalCallerException

   332      *         If this is a named module and the caller's module is not this

   333      *         module

   334      *

   335      * @see #canRead

   336      */

   337     @CallerSensitive

   338     public Module addReads(Module other) {

   339         Objects.requireNonNull(other);

   340         if (this.isNamed()) {

   341             Module caller = getCallerModule(Reflection.getCallerClass());

   342             if (caller != this) {

   343                 throw new IllegalCallerException(caller + " != " + this);

   344             }

   345             implAddReads(other, true);

   346         }

   347         return this;

   348     }

   349 

   350     /**

   351      * Updates this module to read another module.

   352      *

   353      * @apiNote Used by the --add-reads command line option.

   354      */

   355     void implAddReads(Module other) {

   356         implAddReads(other, true);

   357     }

   358 

   359     /**

   360      * Updates this module to read all unnamed modules.

   361      *

   362      * @apiNote Used by the --add-reads command line option.

   363      */

   364     void implAddReadsAllUnnamed() {

   365         implAddReads(Module.ALL_UNNAMED_MODULE, true);

   366     }

   367 

   368     /**

   369      * Updates this module to read another module without notifying the VM.

   370      *

   371      * @apiNote This method is for VM white-box testing.

   372      */

   373     void implAddReadsNoSync(Module other) {

   374         implAddReads(other, false);

   375     }

   376 

   377     /**

   378      * Makes the given {@code Module} readable to this module.

   379      *

   380      * If {@code syncVM} is {@code true} then the VM is notified.

   381      */

   382     private void implAddReads(Module other, boolean syncVM) {

   383         Objects.requireNonNull(other);

   384         if (!canRead(other)) {

   385             // update VM first, just in case it fails

   386             if (syncVM) {

   387                 if (other == ALL_UNNAMED_MODULE) {

   388                     addReads0(this, null);

   389                 } else {

   390                     addReads0(this, other);

   391                 }

   392             }

   393 

   394             // add reflective read

   395             reflectivelyReads.putIfAbsent(this, other, Boolean.TRUE);

   396         }

   397     }

   398 

   399 

   400     // -- exported and open packages --

   401 

   402     // the packages are open to other modules, can be null

   403     // if the value contains EVERYONE_MODULE then the package is open to all

   404     private volatile Map<String, Set<Module>> openPackages;

   405 

   406     // the packages that are exported, can be null

   407     // if the value contains EVERYONE_MODULE then the package is exported to all

   408     private volatile Map<String, Set<Module>> exportedPackages;

   409 

   410     // additional exports or opens added at run-time

   411     // this module (1st key), other module (2nd key)

   412     // (package name, open?) (value)

   413     private static final WeakPairMap<Module, Module, Map<String, Boolean>>

   414         reflectivelyExports = new WeakPairMap<>();

   415 

   416 

   417     /**

   418      * Returns {@code true} if this module exports the given package to at

   419      * least the given module.

   420      *

   421      * <p> This method returns {@code true} if invoked to test if a package in

   422      * this module is exported to itself. It always returns {@code true} when

   423      * invoked on an unnamed module. A package that is {@link #isOpen open} to

   424      * the given module is considered exported to that module at run-time and

   425      * so this method returns {@code true} if the package is open to the given

   426      * module. </p>

   427      *

   428      * <p> This method does not check if the given module reads this module. </p>

   429      *

   430      * @param  pn

   431      *         The package name

   432      * @param  other

   433      *         The other module

   434      *

   435      * @return {@code true} if this module exports the package to at least the

   436      *         given module

   437      *

   438      * @see ModuleDescriptor#exports()

   439      * @see #addExports(String,Module)

   440      */

   441     public boolean isExported(String pn, Module other) {

   442         Objects.requireNonNull(pn);

   443         Objects.requireNonNull(other);

   444         return implIsExportedOrOpen(pn, other, /*open*/false);

   445     }

   446 

   447     /**

   448      * Returns {@code true} if this module has <em>opened</em> a package to at

   449      * least the given module.

   450      *

   451      * <p> This method returns {@code true} if invoked to test if a package in

   452      * this module is open to itself. It returns {@code true} when invoked on an

   453      * {@link ModuleDescriptor#isOpen open} module with a package in the module.

   454      * It always returns {@code true} when invoked on an unnamed module. </p>

   455      *

   456      * <p> This method does not check if the given module reads this module. </p>

   457      *

   458      * @param  pn

   459      *         The package name

   460      * @param  other

   461      *         The other module

   462      *

   463      * @return {@code true} if this module has <em>opened</em> the package

   464      *         to at least the given module

   465      *

   466      * @see ModuleDescriptor#opens()

   467      * @see #addOpens(String,Module)

   468      * @see AccessibleObject#setAccessible(boolean)

   469      * @see java.lang.invoke.MethodHandles#privateLookupIn

   470      */

   471     public boolean isOpen(String pn, Module other) {

   472         Objects.requireNonNull(pn);

   473         Objects.requireNonNull(other);

   474         return implIsExportedOrOpen(pn, other, /*open*/true);

   475     }

   476 

   477     /**

   478      * Returns {@code true} if this module exports the given package

   479      * unconditionally.

   480      *

   481      * <p> This method always returns {@code true} when invoked on an unnamed

   482      * module. A package that is {@link #isOpen(String) opened} unconditionally

   483      * is considered exported unconditionally at run-time and so this method

   484      * returns {@code true} if the package is opened unconditionally. </p>

   485      *

   486      * <p> This method does not check if the given module reads this module. </p>

   487      *

   488      * @param  pn

   489      *         The package name

   490      *

   491      * @return {@code true} if this module exports the package unconditionally

   492      *

   493      * @see ModuleDescriptor#exports()

   494      */

   495     public boolean isExported(String pn) {

   496         Objects.requireNonNull(pn);

   497         return implIsExportedOrOpen(pn, EVERYONE_MODULE, /*open*/false);

   498     }

   499 

   500     /**

   501      * Returns {@code true} if this module has <em>opened</em> a package

   502      * unconditionally.

   503      *

   504      * <p> This method always returns {@code true} when invoked on an unnamed

   505      * module. Additionally, it always returns {@code true} when invoked on an

   506      * {@link ModuleDescriptor#isOpen open} module with a package in the

   507      * module. </p>

   508      *

   509      * <p> This method does not check if the given module reads this module. </p>

   510      *

   511      * @param  pn

   512      *         The package name

   513      *

   514      * @return {@code true} if this module has <em>opened</em> the package

   515      *         unconditionally

   516      *

   517      * @see ModuleDescriptor#opens()

   518      */

   519     public boolean isOpen(String pn) {

   520         Objects.requireNonNull(pn);

   521         return implIsExportedOrOpen(pn, EVERYONE_MODULE, /*open*/true);

   522     }

   523 

   524 

   525     /**

   526      * Returns {@code true} if this module exports or opens the given package

   527      * to the given module. If the other module is {@code EVERYONE_MODULE} then

   528      * this method tests if the package is exported or opened unconditionally.

   529      */

   530     private boolean implIsExportedOrOpen(String pn, Module other, boolean open) {

   531         // all packages in unnamed modules are open

   532         if (!isNamed())

   533             return true;

   534 

   535         // all packages are exported/open to self

   536         if (other == this && containsPackage(pn))

   537             return true;

   538 

   539         // all packages in open and automatic modules are open

   540         if (descriptor.isOpen() || descriptor.isAutomatic())

   541             return containsPackage(pn);

   542 

   543         // exported/opened via module declaration/descriptor

   544         if (isStaticallyExportedOrOpen(pn, other, open))

   545             return true;

   546 

   547         // exported via addExports/addOpens

   548         if (isReflectivelyExportedOrOpen(pn, other, open))

   549             return true;

   550 

   551         // not exported or open to other

   552         return false;

   553     }

   554 

   555     /**

   556      * Returns {@code true} if this module exports or opens a package to

   557      * the given module via its module declaration.

   558      */

   559     private boolean isStaticallyExportedOrOpen(String pn, Module other, boolean open) {

   560         // package is open to everyone or <other>

   561         Map<String, Set<Module>> openPackages = this.openPackages;

   562         if (openPackages != null) {

   563             Set<Module> targets = openPackages.get(pn);

   564             if (targets != null) {

   565                 if (targets.contains(EVERYONE_MODULE))

   566                     return true;

   567                 if (other != EVERYONE_MODULE && targets.contains(other))

   568                     return true;

   569             }

   570         }

   571 

   572         if (!open) {

   573             // package is exported to everyone or <other>

   574             Map<String, Set<Module>> exportedPackages = this.exportedPackages;

   575             if (exportedPackages != null) {

   576                 Set<Module> targets = exportedPackages.get(pn);

   577                 if (targets != null) {

   578                     if (targets.contains(EVERYONE_MODULE))

   579                         return true;

   580                     if (other != EVERYONE_MODULE && targets.contains(other))

   581                         return true;

   582                 }

   583             }

   584         }

   585 

   586         return false;

   587     }

   588 

   589 

   590     /**

   591      * Returns {@code true} if this module reflectively exports or opens given

   592      * package package to the given module.

   593      */

   594     private boolean isReflectivelyExportedOrOpen(String pn, Module other, boolean open) {

   595         // exported or open to all modules

   596         Map<String, Boolean> exports = reflectivelyExports.get(this, EVERYONE_MODULE);

   597         if (exports != null) {

   598             Boolean b = exports.get(pn);

   599             if (b != null) {

   600                 boolean isOpen = b.booleanValue();

   601                 if (!open || isOpen) return true;

   602             }

   603         }

   604 

   605         if (other != EVERYONE_MODULE) {

   606 

   607             // exported or open to other

   608             exports = reflectivelyExports.get(this, other);

   609             if (exports != null) {

   610                 Boolean b = exports.get(pn);

   611                 if (b != null) {

   612                     boolean isOpen = b.booleanValue();

   613                     if (!open || isOpen) return true;

   614                 }

   615             }

   616 

   617             // other is an unnamed module && exported or open to all unnamed

   618             if (!other.isNamed()) {

   619                 exports = reflectivelyExports.get(this, ALL_UNNAMED_MODULE);

   620                 if (exports != null) {

   621                     Boolean b = exports.get(pn);

   622                     if (b != null) {

   623                         boolean isOpen = b.booleanValue();

   624                         if (!open || isOpen) return true;

   625                     }

   626                 }

   627             }

   628 

   629         }

   630 

   631         return false;

   632     }

   633 

   634 

   635     /**

   636      * If the caller's module is this module then update this module to export

   637      * the given package to the given module.

   638      *

   639      * <p> This method has no effect if the package is already exported (or

   640      * <em>open</em>) to the given module. </p>

   641      *

   642      * @apiNote As specified in section 5.4.3 of the <cite>The Java&trade;

   643      * Virtual Machine Specification </cite>, if an attempt to resolve a

   644      * symbolic reference fails because of a linkage error, then subsequent

   645      * attempts to resolve the reference always fail with the same error that

   646      * was thrown as a result of the initial resolution attempt.

   647      *

   648      * @param  pn

   649      *         The package name

   650      * @param  other

   651      *         The module

   652      *

   653      * @return this module

   654      *

   655      * @throws IllegalArgumentException

   656      *         If {@code pn} is {@code null}, or this is a named module and the

   657      *         package {@code pn} is not a package in this module

   658      * @throws IllegalCallerException

   659      *         If this is a named module and the caller's module is not this

   660      *         module

   661      *

   662      * @jvms 5.4.3 Resolution

   663      * @see #isExported(String,Module)

   664      */

   665     @CallerSensitive

   666     public Module addExports(String pn, Module other) {

   667         if (pn == null)

   668             throw new IllegalArgumentException("package is null");

   669         Objects.requireNonNull(other);

   670 

   671         if (isNamed()) {

   672             Module caller = getCallerModule(Reflection.getCallerClass());

   673             if (caller != this) {

   674                 throw new IllegalCallerException(caller + " != " + this);

   675             }

   676             implAddExportsOrOpens(pn, other, /*open*/false, /*syncVM*/true);

   677         }

   678 

   679         return this;

   680     }

   681 

   682     /**

   683      * If this module has <em>opened</em> a package to at least the caller

   684      * module then update this module to open the package to the given module.

   685      * Opening a package with this method allows all types in the package,

   686      * and all their members, not just public types and their public members,

   687      * to be reflected on by the given module when using APIs that support

   688      * private access or a way to bypass or suppress default Java language

   689      * access control checks.

   690      *

   691      * <p> This method has no effect if the package is already <em>open</em>

   692      * to the given module. </p>

   693      *

   694      * @param  pn

   695      *         The package name

   696      * @param  other

   697      *         The module

   698      *

   699      * @return this module

   700      *

   701      * @throws IllegalArgumentException

   702      *         If {@code pn} is {@code null}, or this is a named module and the

   703      *         package {@code pn} is not a package in this module

   704      * @throws IllegalCallerException

   705      *         If this is a named module and this module has not opened the

   706      *         package to at least the caller's module

   707      *

   708      * @see #isOpen(String,Module)

   709      * @see AccessibleObject#setAccessible(boolean)

   710      * @see java.lang.invoke.MethodHandles#privateLookupIn

   711      */

   712     @CallerSensitive

   713     public Module addOpens(String pn, Module other) {

   714         if (pn == null)

   715             throw new IllegalArgumentException("package is null");

   716         Objects.requireNonNull(other);

   717 

   718         if (isNamed()) {

   719             Module caller = getCallerModule(Reflection.getCallerClass());

   720             if (caller != this && (caller == null || !isOpen(pn, caller)))

   721                 throw new IllegalCallerException(pn + " is not open to " + caller);

   722             implAddExportsOrOpens(pn, other, /*open*/true, /*syncVM*/true);

   723         }

   724 

   725         return this;

   726     }

   727 

   728 

   729     /**

   730      * Updates this module to export a package unconditionally.

   731      *

   732      * @apiNote This method is for JDK tests only.

   733      */

   734     void implAddExports(String pn) {

   735         implAddExportsOrOpens(pn, Module.EVERYONE_MODULE, false, true);

   736     }

   737 

   738     /**

   739      * Updates this module to export a package to another module.

   740      *

   741      * @apiNote Used by Instrumentation::redefineModule and --add-exports

   742      */

   743     void implAddExports(String pn, Module other) {

   744         implAddExportsOrOpens(pn, other, false, true);

   745     }

   746 

   747     /**

   748      * Updates this module to export a package to all unnamed modules.

   749      *

   750      * @apiNote Used by the --add-exports command line option.

   751      */

   752     void implAddExportsToAllUnnamed(String pn) {

   753         implAddExportsOrOpens(pn, Module.ALL_UNNAMED_MODULE, false, true);

   754     }

   755 

   756     /**

   757      * Updates this export to export a package unconditionally without

   758      * notifying the VM.

   759      *

   760      * @apiNote This method is for VM white-box testing.

   761      */

   762     void implAddExportsNoSync(String pn) {

   763         implAddExportsOrOpens(pn.replace('/', '.'), Module.EVERYONE_MODULE, false, false);

   764     }

   765 

   766     /**

   767      * Updates a module to export a package to another module without

   768      * notifying the VM.

   769      *

   770      * @apiNote This method is for VM white-box testing.

   771      */

   772     void implAddExportsNoSync(String pn, Module other) {

   773         implAddExportsOrOpens(pn.replace('/', '.'), other, false, false);

   774     }

   775 

   776     /**

   777      * Updates this module to open a package unconditionally.

   778      *

   779      * @apiNote This method is for JDK tests only.

   780      */

   781     void implAddOpens(String pn) {

   782         implAddExportsOrOpens(pn, Module.EVERYONE_MODULE, true, true);

   783     }

   784 

   785     /**

   786      * Updates this module to open a package to another module.

   787      *

   788      * @apiNote Used by Instrumentation::redefineModule and --add-opens

   789      */

   790     void implAddOpens(String pn, Module other) {

   791         implAddExportsOrOpens(pn, other, true, true);

   792     }

   793 

   794     /**

   795      * Updates this module to export a package to all unnamed modules.

   796      *

   797      * @apiNote Used by the --add-opens command line option.

   798      */

   799     void implAddOpensToAllUnnamed(String pn) {

   800         implAddExportsOrOpens(pn, Module.ALL_UNNAMED_MODULE, true, true);

   801     }

   802 

   803 

   804     /**

   805      * Updates a module to export or open a module to another module.

   806      *

   807      * If {@code syncVM} is {@code true} then the VM is notified.

   808      */

   809     private void implAddExportsOrOpens(String pn,

   810                                        Module other,

   811                                        boolean open,

   812                                        boolean syncVM) {

   813         Objects.requireNonNull(other);

   814         Objects.requireNonNull(pn);

   815 

   816         // all packages are open in unnamed, open, and automatic modules

   817         if (!isNamed() || descriptor.isOpen() || descriptor.isAutomatic())

   818             return;

   819 

   820         // nothing to do if already exported/open to other

   821         if (implIsExportedOrOpen(pn, other, open))

   822             return;

   823 

   824         // can only export a package in the module

   825         if (!containsPackage(pn)) {

   826             throw new IllegalArgumentException("package " + pn

   827                                                + " not in contents");

   828         }

   829 

   830         // update VM first, just in case it fails

   831         if (syncVM) {

   832             if (other == EVERYONE_MODULE) {

   833                 addExportsToAll0(this, pn);

   834             } else if (other == ALL_UNNAMED_MODULE) {

   835                 addExportsToAllUnnamed0(this, pn);

   836             } else {

   837                 addExports0(this, pn, other);

   838             }

   839         }

   840 

   841         // add package name to reflectivelyExports if absent

   842         Map<String, Boolean> map = reflectivelyExports

   843             .computeIfAbsent(this, other,

   844                              (m1, m2) -> new ConcurrentHashMap<>());

   845 

   846         if (open) {

   847             map.put(pn, Boolean.TRUE);  // may need to promote from FALSE to TRUE

   848         } else {

   849             map.putIfAbsent(pn, Boolean.FALSE);

   850         }

   851     }

   852 

   853 

   854     // -- services --

   855 

   856     // additional service type (2nd key) that some module (1st key) uses

   857     private static final WeakPairMap<Module, Class<?>, Boolean> reflectivelyUses

   858         = new WeakPairMap<>();

   859 

   860     /**

   861      * If the caller's module is this module then update this module to add a

   862      * service dependence on the given service type. This method is intended

   863      * for use by frameworks that invoke {@link java.util.ServiceLoader

   864      * ServiceLoader} on behalf of other modules or where the framework is

   865      * passed a reference to the service type by other code. This method is

   866      * a no-op when invoked on an unnamed module or an automatic module.

   867      *

   868      * <p> This method does not cause {@link Configuration#resolveAndBind

   869      * resolveAndBind} to be re-run. </p>

   870      *

   871      * @param  service

   872      *         The service type

   873      *

   874      * @return this module

   875      *

   876      * @throws IllegalCallerException

   877      *         If this is a named module and the caller's module is not this

   878      *         module

   879      *

   880      * @see #canUse(Class)

   881      * @see ModuleDescriptor#uses()

   882      */

   883     @CallerSensitive

   884     public Module addUses(Class<?> service) {

   885         Objects.requireNonNull(service);

   886 

   887         if (isNamed() && !descriptor.isAutomatic()) {

   888             Module caller = getCallerModule(Reflection.getCallerClass());

   889             if (caller != this) {

   890                 throw new IllegalCallerException(caller + " != " + this);

   891             }

   892             implAddUses(service);

   893         }

   894 

   895         return this;

   896     }

   897 

   898     /**

   899      * Update this module to add a service dependence on the given service

   900      * type.

   901      */

   902     void implAddUses(Class<?> service) {

   903         if (!canUse(service)) {

   904             reflectivelyUses.putIfAbsent(this, service, Boolean.TRUE);

   905         }

   906     }

   907 

   908 

   909     /**

   910      * Indicates if this module has a service dependence on the given service

   911      * type. This method always returns {@code true} when invoked on an unnamed

   912      * module or an automatic module.

   913      *

   914      * @param  service

   915      *         The service type

   916      *

   917      * @return {@code true} if this module uses service type {@code st}

   918      *

   919      * @see #addUses(Class)

   920      */

   921     public boolean canUse(Class<?> service) {

   922         Objects.requireNonNull(service);

   923 

   924         if (!isNamed())

   925             return true;

   926 

   927         if (descriptor.isAutomatic())

   928             return true;

   929 

   930         // uses was declared

   931         if (descriptor.uses().contains(service.getName()))

   932             return true;

   933 

   934         // uses added via addUses

   935         return reflectivelyUses.containsKeyPair(this, service);

   936     }

   937 

   938 

   939 

   940     // -- packages --

   941 

   942     // Additional packages that are added to the module at run-time.

   943     private volatile Map<String, Boolean> extraPackages;

   944 

   945     private boolean containsPackage(String pn) {

   946         if (descriptor.packages().contains(pn))

   947             return true;

   948         Map<String, Boolean> extraPackages = this.extraPackages;

   949         if (extraPackages != null && extraPackages.containsKey(pn))

   950             return true;

   951         return false;

   952     }

   953 

   954 

   955     /**

   956      * Returns the set of package names for the packages in this module.

   957      *

   958      * <p> For named modules, the returned set contains an element for each

   959      * package in the module. </p>

   960      *

   961      * <p> For unnamed modules, this method is the equivalent to invoking the

   962      * {@link ClassLoader#getDefinedPackages() getDefinedPackages} method of

   963      * this module's class loader and returning the set of package names. </p>

   964      *

   965      * @return the set of the package names of the packages in this module

   966      */

   967     public Set<String> getPackages() {

   968         if (isNamed()) {

   969 

   970             Set<String> packages = descriptor.packages();

   971             Map<String, Boolean> extraPackages = this.extraPackages;

   972             if (extraPackages == null) {

   973                 return packages;

   974             } else {

   975                 return Stream.concat(packages.stream(),

   976                                      extraPackages.keySet().stream())

   977                         .collect(Collectors.toSet());

   978             }

   979 

   980         } else {

   981             // unnamed module

   982             Stream<Package> packages;

   983             if (loader == null) {

   984                 packages = BootLoader.packages();

   985             } else {

   986                 packages = SharedSecrets.getJavaLangAccess().packages(loader);

   987             }

   988             return packages.map(Package::getName).collect(Collectors.toSet());

   989         }

   990     }

   991 

   992     /**

   993      * Add a package to this module without notifying the VM.

   994      *

   995      * @apiNote This method is VM white-box testing.

   996      */

   997     void implAddPackageNoSync(String pn) {

   998         implAddPackage(pn.replace('/', '.'), false);

   999     }

  1000 

  1001     /**

  1002      * Add a package to this module.

  1003      *

  1004      * If {@code syncVM} is {@code true} then the VM is notified. This method is

  1005      * a no-op if this is an unnamed module or the module already contains the

  1006      * package.

  1007      *

  1008      * @throws IllegalArgumentException if the package name is not legal

  1009      * @throws IllegalStateException if the package is defined to another module

  1010      */

  1011     private void implAddPackage(String pn, boolean syncVM) {

  1012         // no-op if unnamed module

  1013         if (!isNamed())

  1014             return;

  1015 

  1016         // no-op if module contains the package

  1017         if (containsPackage(pn))

  1018             return;

  1019 

  1020         // check package name is legal for named modules

  1021         if (pn.isEmpty())

  1022             throw new IllegalArgumentException("Cannot add <unnamed> package");

  1023         for (int i=0; i<pn.length(); i++) {

  1024             char c = pn.charAt(i);

  1025             if (c == '/' || c == ';' || c == '[') {

  1026                 throw new IllegalArgumentException("Illegal character: " + c);

  1027             }

  1028         }

  1029 

  1030         // create extraPackages if needed

  1031         Map<String, Boolean> extraPackages = this.extraPackages;

  1032         if (extraPackages == null) {

  1033             synchronized (this) {

  1034                 extraPackages = this.extraPackages;

  1035                 if (extraPackages == null)

  1036                     this.extraPackages = extraPackages = new ConcurrentHashMap<>();

  1037             }

  1038         }

  1039 

  1040         // update VM first in case it fails. This is a no-op if another thread

  1041         // beats us to add the package first

  1042         if (syncVM) {

  1043             // throws IllegalStateException if defined to another module

  1044             addPackage0(this, pn);

  1045             if (descriptor.isOpen() || descriptor.isAutomatic()) {

  1046                 addExportsToAll0(this, pn);

  1047             }

  1048         }

  1049         extraPackages.putIfAbsent(pn, Boolean.TRUE);

  1050     }

  1051 

  1052 

  1053     // -- creating Module objects --

  1054 

  1055     /**

  1056      * Defines all module in a configuration to the runtime.

  1057      *

  1058      * @return a map of module name to runtime {@code Module}

  1059      *

  1060      * @throws IllegalArgumentException

  1061      *         If defining any of the modules to the VM fails

  1062      */

  1063     static Map<String, Module> defineModules(Configuration cf,

  1064                                              Function<String, ClassLoader> clf,

  1065                                              ModuleLayer layer)

  1066     {

  1067         Map<String, Module> nameToModule = new HashMap<>();

  1068         Map<String, ClassLoader> moduleToLoader = new HashMap<>();

  1069 

  1070         boolean isBootLayer = (ModuleLayer.boot() == null);

  1071         Set<ClassLoader> loaders = new HashSet<>();

  1072 

  1073         // map each module to a class loader

  1074         for (ResolvedModule resolvedModule : cf.modules()) {

  1075             String name = resolvedModule.name();

  1076             ClassLoader loader = clf.apply(name);

  1077             if (loader != null) {

  1078                 moduleToLoader.put(name, loader);

  1079                 loaders.add(loader);

  1080             } else if (!isBootLayer) {

  1081                 throw new IllegalArgumentException("loader can't be 'null'");

  1082             }

  1083         }

  1084 

  1085         // define each module in the configuration to the VM

  1086         for (ResolvedModule resolvedModule : cf.modules()) {

  1087             ModuleReference mref = resolvedModule.reference();

  1088             ModuleDescriptor descriptor = mref.descriptor();

  1089             String name = descriptor.name();

  1090             URI uri = mref.location().orElse(null);

  1091             ClassLoader loader = moduleToLoader.get(resolvedModule.name());

  1092             Module m;

  1093             if (loader == null && isBootLayer && name.equals("java.base")) {

  1094                 // java.base is already defined to the VM

  1095                 m = Object.class.getModule();

  1096             } else {

  1097                 m = new Module(layer, loader, descriptor, uri);

  1098             }

  1099             nameToModule.put(name, m);

  1100             moduleToLoader.put(name, loader);

  1101         }

  1102 

  1103         // setup readability and exports

  1104         for (ResolvedModule resolvedModule : cf.modules()) {

  1105             ModuleReference mref = resolvedModule.reference();

  1106             ModuleDescriptor descriptor = mref.descriptor();

  1107 

  1108             String mn = descriptor.name();

  1109             Module m = nameToModule.get(mn);

  1110             assert m != null;

  1111 

  1112             // reads

  1113             Set<Module> reads = new HashSet<>();

  1114 

  1115             // name -> source Module when in parent layer

  1116             Map<String, Module> nameToSource = Collections.emptyMap();

  1117 

  1118             for (ResolvedModule other : resolvedModule.reads()) {

  1119                 Module m2 = null;

  1120                 if (other.configuration() == cf) {

  1121                     // this configuration

  1122                     m2 = nameToModule.get(other.name());

  1123                     assert m2 != null;

  1124                 } else {

  1125                     // parent layer

  1126                     for (ModuleLayer parent: layer.parents()) {

  1127                         m2 = findModule(parent, other);

  1128                         if (m2 != null)

  1129                             break;

  1130                     }

  1131                     assert m2 != null;

  1132                     if (nameToSource.isEmpty())

  1133                         nameToSource = new HashMap<>();

  1134                     nameToSource.put(other.name(), m2);