1/* 2 * Copyright (c) 2015, 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/* 27 * This file is available under and governed by the GNU General Public 28 * License version 2 only, as published by the Free Software Foundation. 29 * However, the following notice accompanied the original version of this 30 * file, and Oracle licenses the original version of this file under the BSD 31 * license: 32 */ 33/* 34 Copyright 2009-2015 Attila Szegedi 35 36 Licensed under both the Apache License, Version 2.0 (the "Apache License") 37 and the BSD License (the "BSD License"), with licensee being free to 38 choose either of the two at their discretion. 39 40 You may not use this file except in compliance with either the Apache 41 License or the BSD License. 42 43 If you choose to use this file in compliance with the Apache License, the 44 following notice applies to you: 45 46 You may obtain a copy of the Apache License at 47 48 http://www.apache.org/licenses/LICENSE-2.0 49 50 Unless required by applicable law or agreed to in writing, software 51 distributed under the License is distributed on an "AS IS" BASIS, 52 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or 53 implied. See the License for the specific language governing 54 permissions and limitations under the License. 55 56 If you choose to use this file in compliance with the BSD License, the 57 following notice applies to you: 58 59 Redistribution and use in source and binary forms, with or without 60 modification, are permitted provided that the following conditions are 61 met: 62 * Redistributions of source code must retain the above copyright 63 notice, this list of conditions and the following disclaimer. 64 * Redistributions in binary form must reproduce the above copyright 65 notice, this list of conditions and the following disclaimer in the 66 documentation and/or other materials provided with the distribution. 67 * Neither the name of the copyright holder nor the names of 68 contributors may be used to endorse or promote products derived from 69 this software without specific prior written permission. 70 71 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS 72 IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 73 TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A 74 PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL COPYRIGHT HOLDER 75 BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 76 CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 77 SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR 78 BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 79 WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR 80 OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF 81 ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 82*/ 83 84package jdk.dynalink.linker.support; 85 86import java.lang.invoke.MethodHandle; 87import java.lang.invoke.MethodHandles; 88import java.lang.invoke.MethodType; 89import jdk.dynalink.DynamicLinkerFactory; 90import jdk.dynalink.linker.MethodHandleTransformer; 91 92/** 93 * Default implementation for a 94 * {@link DynamicLinkerFactory#setInternalObjectsFilter(MethodHandleTransformer)} 95 * that delegates to a pair of filtering method handles. It takes a method 96 * handle of {@code Object(Object)} type for filtering parameter values and 97 * another one of the same type for filtering return values. It applies them as 98 * parameter and return value filters on method handles passed to its 99 * {@link #transform(MethodHandle)} method, on those parameters and return values 100 * that are declared to have type {@link Object}. Also handles 101 * {@link MethodHandle#isVarargsCollector() method handles that support variable 102 * arity calls} with a last {@code Object[]} parameter. You can broadly think of 103 * the parameter filter as being a wrapping method for exposing internal runtime 104 * objects wrapped into an adapter with some public interface, and the return 105 * value filter as being its inverse unwrapping method. 106 */ 107public class DefaultInternalObjectFilter implements MethodHandleTransformer { 108 private static final MethodHandle FILTER_VARARGS = new Lookup(MethodHandles.lookup()).findStatic( 109 DefaultInternalObjectFilter.class, "filterVarArgs", MethodType.methodType(Object[].class, MethodHandle.class, Object[].class)); 110 111 private final MethodHandle parameterFilter; 112 private final MethodHandle returnFilter; 113 private final MethodHandle varArgFilter; 114 115 /** 116 * Creates a new filter. 117 * @param parameterFilter the filter for method parameters. Must be of type 118 * {@code Object(Object)}, or {@code null}. 119 * @param returnFilter the filter for return values. Must be of type 120 * {@code Object(Object)}, or {@code null}. 121 * @throws IllegalArgumentException if one or both filters are not of the 122 * expected type. 123 */ 124 public DefaultInternalObjectFilter(final MethodHandle parameterFilter, final MethodHandle returnFilter) { 125 this.parameterFilter = checkHandle(parameterFilter, "parameterFilter"); 126 this.returnFilter = checkHandle(returnFilter, "returnFilter"); 127 this.varArgFilter = parameterFilter == null ? null : FILTER_VARARGS.bindTo(parameterFilter); 128 } 129 130 @Override 131 public MethodHandle transform(final MethodHandle target) { 132 assert target != null; 133 MethodHandle[] filters = null; 134 final MethodType type = target.type(); 135 final boolean isVarArg = target.isVarargsCollector(); 136 final int paramCount = type.parameterCount(); 137 final MethodHandle paramsFiltered; 138 // Filter parameters 139 if (parameterFilter != null) { 140 int firstFilter = -1; 141 // Ignore receiver, start from argument 1 142 for(int i = 1; i < paramCount; ++i) { 143 final Class<?> paramType = type.parameterType(i); 144 final boolean filterVarArg = isVarArg && i == paramCount - 1 && paramType == Object[].class; 145 if (filterVarArg || paramType == Object.class) { 146 if (filters == null) { 147 firstFilter = i; 148 filters = new MethodHandle[paramCount - firstFilter]; 149 } 150 filters[i - firstFilter] = filterVarArg ? varArgFilter : parameterFilter; 151 } 152 } 153 paramsFiltered = filters != null ? MethodHandles.filterArguments(target, firstFilter, filters) : target; 154 } else { 155 paramsFiltered = target; 156 } 157 // Filter return value if needed 158 final MethodHandle returnFiltered = returnFilter != null && type.returnType() == Object.class ? MethodHandles.filterReturnValue(paramsFiltered, returnFilter) : paramsFiltered; 159 // Preserve varargs collector state 160 return isVarArg && !returnFiltered.isVarargsCollector() ? returnFiltered.asVarargsCollector(type.parameterType(paramCount - 1)) : returnFiltered; 161 162 } 163 164 private static MethodHandle checkHandle(final MethodHandle handle, final String handleKind) { 165 if (handle != null) { 166 final MethodType objectObjectType = MethodType.methodType(Object.class, Object.class); 167 if (!handle.type().equals(objectObjectType)) { 168 throw new IllegalArgumentException("Method type for " + handleKind + " must be " + objectObjectType); 169 } 170 } 171 return handle; 172 } 173 174 @SuppressWarnings("unused") 175 private static Object[] filterVarArgs(final MethodHandle parameterFilter, final Object[] args) throws Throwable { 176 Object[] newArgs = null; 177 for(int i = 0; i < args.length; ++i) { 178 final Object arg = args[i]; 179 final Object newArg = parameterFilter.invokeExact(arg); 180 if (arg != newArg) { 181 if (newArgs == null) { 182 newArgs = args.clone(); 183 } 184 newArgs[i] = newArg; 185 } 186 } 187 return newArgs == null ? args : newArgs; 188 } 189} 190