1 /*

     2  * Copyright (c) 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.

     8  *

     9  * This code is distributed in the hope that it will be useful, but WITHOUT

    10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

    11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

    12  * version 2 for more details (a copy is included in the LICENSE file that

    13  * accompanied this code).

    14  *

    15  * You should have received a copy of the GNU General Public License version

    16  * 2 along with this work; if not, write to the Free Software Foundation,

    17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

    18  *

    19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

    20  * or visit www.oracle.com if you need additional information or have any

    21  * questions.

    22  */

    23 

    24 import java.io.InputStream;

    25 import java.io.IOException;

    26 import java.lang.module.ModuleReader;

    27 import java.lang.module.ModuleReference;

    28 import java.net.URI;

    29 import java.nio.file.Files;

    30 import java.nio.file.Path;

    31 import java.nio.file.Paths;

    32 import jdk.internal.module.ClassFileConstants;

    33 import jdk.internal.module.ClassFileAttributes;

    34 import jdk.internal.module.ClassFileAttributes.ModuleTargetAttribute;

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

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

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

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

    39 

    40 public class ModuleTargetHelper {

    41     private ModuleTargetHelper() {}

    42 

    43     public static final class ModuleTarget {

    44         private String osName, osArch;

    45 

    46         public ModuleTarget(String osName, String osArch) {

    47             this.osName = osName;

    48             this.osArch = osArch;

    49         }

    50 

    51         public String osName() {

    52             return osName;

    53         }

    54 

    55         public String osArch() {

    56             return osArch;

    57         }

    58     }

    59 

    60     public static ModuleTarget getJavaBaseTarget() throws IOException {

    61         Path p = Paths.get(URI.create("jrt:/modules/java.base/module-info.class"));

    62         try (InputStream in = Files.newInputStream(p)) {

    63             return read(in);

    64         }

    65     }

    66 

    67     public static ModuleTarget read(InputStream in) throws IOException {

    68         ModuleTargetAttribute[] modTargets = new ModuleTargetAttribute[1];

    69         ClassVisitor cv = new ClassVisitor(Opcodes.ASM5) {

    70             @Override

    71             public void visitAttribute(Attribute attr) {

    72                 if (attr instanceof ModuleTargetAttribute) {

    73                     modTargets[0] = (ModuleTargetAttribute)attr;

    74                 }

    75             }

    76         };

    77 

    78         // prototype of attributes that should be parsed

    79         Attribute[] attrs = new Attribute[] {

    80             new ModuleTargetAttribute()

    81         };

    82 

    83         // parse module-info.class

    84         ClassReader cr = new ClassReader(in);

    85         cr.accept(cv, attrs, 0);

    86         if (modTargets[0] != null) {

    87             return new ModuleTarget(modTargets[0].osName(), modTargets[0].osArch());

    88         }

    89 

    90         return null;

    91     }

    92 

    93     public static ModuleTarget read(ModuleReference modRef) throws IOException {

    94         ModuleReader reader = modRef.open();

    95         try (InputStream in = reader.open("module-info.class").get()) {

    96             return read(in);

    97         } finally {

    98             reader.close();

    99         }

   100     }

   101 }