1 /* 2 * Copyright (c) 2010, 2013, 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.nashorn.internal.runtime; 27 28 import static jdk.nashorn.internal.codegen.Compiler.SCRIPTS_PACKAGE; 29 import static jdk.nashorn.internal.codegen.Compiler.binaryName; 30 import static jdk.nashorn.internal.codegen.CompilerConstants.JS_OBJECT_DUAL_FIELD_PREFIX; 31 import static jdk.nashorn.internal.codegen.CompilerConstants.JS_OBJECT_SINGLE_FIELD_PREFIX; 32 33 import java.lang.module.ModuleDescriptor; 34 import java.lang.reflect.Module; 35 import java.security.ProtectionDomain; 36 import jdk.nashorn.internal.codegen.ObjectClassGenerator; 37 38 /** 39 * Responsible for on the fly construction of structure classes. 40 */ 41 final class StructureLoader extends NashornLoader { 42 private static final String SINGLE_FIELD_PREFIX = binaryName(SCRIPTS_PACKAGE) + '.' + JS_OBJECT_SINGLE_FIELD_PREFIX.symbolName(); 43 private static final String DUAL_FIELD_PREFIX = binaryName(SCRIPTS_PACKAGE) + '.' + JS_OBJECT_DUAL_FIELD_PREFIX.symbolName(); 44 45 private final Module structuresModule; 46 47 /** 48 * Constructor. 49 */ 50 StructureLoader(final ClassLoader parent) { 51 super(parent); 52 53 // new structures module, it's exports, read edges 54 structuresModule = createModule("jdk.scripting.nashorn.structures"); 55 56 // specific exports from nashorn to the structures module 57 NASHORN_MODULE.addExports(SCRIPTS_PKG, structuresModule); 58 NASHORN_MODULE.addExports(RUNTIME_PKG, structuresModule); 59 60 // nashorn has to read fields from classes of the new module 61 NASHORN_MODULE.addReads(structuresModule); 62 } 63 64 private Module createModule(final String moduleName) { 65 final ModuleDescriptor descriptor 66 = new ModuleDescriptor.Builder(moduleName) 67 .requires("java.base") 68 .requires(NASHORN_MODULE.getName()) 69 .conceals(SCRIPTS_PKG) 70 .build(); 71 72 final Module mod = Context.createModuleTrusted(descriptor, this); 73 loadModuleManipulator(); 74 return mod; 75 } 76 77 /** 78 * Returns true if the class name represents a structure object with dual primitive/object fields. 79 * @param name a class name 80 * @return true if a dual field structure class 81 */ 82 private static boolean isDualFieldStructure(final String name) { 83 return name.startsWith(DUAL_FIELD_PREFIX); 84 } 85 86 /** 87 * Returns true if the class name represents a structure object with single object-only fields. 88 * @param name a class name 89 * @return true if a single field structure class 90 */ 91 static boolean isSingleFieldStructure(final String name) { 92 return name.startsWith(SINGLE_FIELD_PREFIX); 93 } 94 95 /** 96 * Returns true if the class name represents a Nashorn structure object. 97 * @param name a class name 98 * @return true if a structure class 99 */ 100 static boolean isStructureClass(final String name) { 101 return isDualFieldStructure(name) || isSingleFieldStructure(name); 102 } 103 104 Module getModule() { 105 return structuresModule; 106 } 107 108 @Override 109 protected Class<?> findClass(final String name) throws ClassNotFoundException { 110 if (isDualFieldStructure(name)) { 111 return generateClass(name, name.substring(DUAL_FIELD_PREFIX.length()), true); 112 } else if (isSingleFieldStructure(name)) { 113 return generateClass(name, name.substring(SINGLE_FIELD_PREFIX.length()), false); 114 } 115 return super.findClass(name); 116 } 117 118 /** 119 * Generate a layout class. 120 * @param name Name of class. 121 * @param descriptor Layout descriptor. 122 * @return Generated class. 123 */ 124 private Class<?> generateClass(final String name, final String descriptor, final boolean dualFields) { 125 final Context context = Context.getContextTrusted(); 126 127 final byte[] code = new ObjectClassGenerator(context, dualFields).generate(descriptor); 128 return defineClass(name, code, 0, code.length, new ProtectionDomain(null, getPermissions(null))); 129 } 130 }