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 24import java.io.InputStream; 25import java.io.IOException; 26import java.lang.module.ModuleReader; 27import java.lang.module.ModuleReference; 28import java.net.URI; 29import java.nio.file.Files; 30import java.nio.file.Path; 31import java.nio.file.Paths; 32import jdk.internal.module.ClassFileConstants; 33import jdk.internal.module.ClassFileAttributes; 34import jdk.internal.module.ClassFileAttributes.ModuleTargetAttribute; 35import jdk.internal.org.objectweb.asm.Attribute; 36import jdk.internal.org.objectweb.asm.ClassReader; 37import jdk.internal.org.objectweb.asm.ClassVisitor; 38import jdk.internal.org.objectweb.asm.Opcodes; 39 40public class ModuleTargetHelper { 41 private ModuleTargetHelper() {} 42 43 public static final class ModuleTarget { 44 private String targetPlatform; 45 46 public ModuleTarget(String targetPlatform) { 47 this.targetPlatform = targetPlatform; 48 } 49 50 public String targetPlatform() { 51 return targetPlatform; 52 } 53 } 54 55 public static ModuleTarget getJavaBaseTarget() throws IOException { 56 Path p = Paths.get(URI.create("jrt:/modules/java.base/module-info.class")); 57 try (InputStream in = Files.newInputStream(p)) { 58 return read(in); 59 } 60 } 61 62 public static ModuleTarget read(InputStream in) throws IOException { 63 ModuleTargetAttribute[] modTargets = new ModuleTargetAttribute[1]; 64 ClassVisitor cv = new ClassVisitor(Opcodes.ASM5) { 65 @Override 66 public void visitAttribute(Attribute attr) { 67 if (attr instanceof ModuleTargetAttribute) { 68 modTargets[0] = (ModuleTargetAttribute)attr; 69 } 70 } 71 }; 72 73 // prototype of attributes that should be parsed 74 Attribute[] attrs = new Attribute[] { 75 new ModuleTargetAttribute() 76 }; 77 78 // parse module-info.class 79 ClassReader cr = new ClassReader(in); 80 cr.accept(cv, attrs, 0); 81 if (modTargets[0] != null) { 82 return new ModuleTarget(modTargets[0].targetPlatform()); 83 } 84 85 return null; 86 } 87 88 public static ModuleTarget read(ModuleReference modRef) throws IOException { 89 ModuleReader reader = modRef.open(); 90 try (InputStream in = reader.open("module-info.class").get()) { 91 return read(in); 92 } finally { 93 reader.close(); 94 } 95 } 96} 97