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 package jdk.vm.ci.services.internal;
  24 
  25 import java.lang.reflect.Method;
  26 import java.util.Set;
  27 
  28 import jdk.vm.ci.services.Services;
  29 
  30 /**
  31  * Reflection based access to API introduced in JDK 9. This allows the API to be used in code that
  32  * must be compiled (but not executed) on JDK 8.
  33  */
  34 public final class ReflectionAccessJDK {
  35 
  36     /**
  37      * {@code Class.getModule()}.
  38      */
  39     private static final Method getModule;
  40 
  41     /**
  42      * {@code java.lang.Module.addOpens(String, Module)}.
  43      */
  44     private static final Method addOpens;
  45 
  46     /**
  47      * {@code java.lang.Module.getPackages(Module, String, Module)}.
  48      */
  49     private static final Method getPackages;
  50 
  51     /**
  52      * {@code java.lang.Module.isOpen(String, Module)}.
  53      */
  54     private static final Method isOpenTo;
  55 
  56     /**
  57      * Opens all JVMCI packages to the module of a given class.
  58      *
  59      * @param other all JVMCI packages will be opened to the module of this class
  60      */
  61     @SuppressWarnings("unchecked")
  62     public static void openJVMCITo(Class<?> other) {
  63         try {
  64             Object jvmci = getModule.invoke(Services.class);
  65             Object otherModule = getModule.invoke(other);
  66             if (jvmci != otherModule) {
  67                 Set<String> packages = (Set<String>) getPackages.invoke(jvmci);
  68                 for (String pkg : packages) {
  69                     boolean opened = (Boolean) isOpenTo.invoke(jvmci, pkg, otherModule);
  70                     if (!opened) {
  71                         addOpens.invoke(jvmci, pkg, otherModule);
  72                     }
  73                 }
  74             }
  75         } catch (Exception e) {
  76             throw new InternalError(e);
  77         }
  78     }
  79 
  80     static {
  81         try {
  82             getModule = Class.class.getMethod("getModule");
  83             Class<?> moduleClass = getModule.getReturnType();
  84             getPackages = moduleClass.getMethod("getPackages");
  85             isOpenTo = moduleClass.getMethod("isOpen", String.class, moduleClass);
  86             addOpens = moduleClass.getDeclaredMethod("addOpens", String.class, moduleClass);
  87         } catch (NoSuchMethodException | SecurityException e) {
  88             throw new InternalError(e);
  89         }
  90     }
  91 }