--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/src/jdk.dynalink/share/classes/jdk/dynalink/linker/support/Guards.java Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,338 @@
+/*
+ * Copyright (c) 2010, 2013, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation. Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/*
+ * This file is available under and governed by the GNU General Public
+ * License version 2 only, as published by the Free Software Foundation.
+ * However, the following notice accompanied the original version of this
+ * file, and Oracle licenses the original version of this file under the BSD
+ * license:
+ */
+/*
+ Copyright 2009-2013 Attila Szegedi
+
+ Licensed under both the Apache License, Version 2.0 (the "Apache License")
+ and the BSD License (the "BSD License"), with licensee being free to
+ choose either of the two at their discretion.
+
+ You may not use this file except in compliance with either the Apache
+ License or the BSD License.
+
+ If you choose to use this file in compliance with the Apache License, the
+ following notice applies to you:
+
+ You may obtain a copy of the Apache License at
+
+ http://www.apache.org/licenses/LICENSE-2.0
+
+ Unless required by applicable law or agreed to in writing, software
+ distributed under the License is distributed on an "AS IS" BASIS,
+ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+ implied. See the License for the specific language governing
+ permissions and limitations under the License.
+
+ If you choose to use this file in compliance with the BSD License, the
+ following notice applies to you:
+
+ Redistribution and use in source and binary forms, with or without
+ modification, are permitted provided that the following conditions are
+ met:
+ * Redistributions of source code must retain the above copyright
+ notice, this list of conditions and the following disclaimer.
+ * Redistributions in binary form must reproduce the above copyright
+ notice, this list of conditions and the following disclaimer in the
+ documentation and/or other materials provided with the distribution.
+ * Neither the name of the copyright holder nor the names of
+ contributors may be used to endorse or promote products derived from
+ this software without specific prior written permission.
+
+ THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
+ IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+ TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
+ PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL COPYRIGHT HOLDER
+ BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
+ BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
+ OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+
+package jdk.dynalink.linker.support;
+
+import java.lang.invoke.MethodHandle;
+import java.lang.invoke.MethodHandles;
+import java.lang.invoke.MethodType;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+import jdk.dynalink.DynamicLinker;
+import jdk.dynalink.linker.LinkerServices;
+
+/**
+ * Utility methods for creating typical guards for
+ * {@link MethodHandles#guardWithTest(MethodHandle, MethodHandle, MethodHandle)}
+ * and for adjusting their method types.
+ */
+public final class Guards {
+ private static final Logger LOG = Logger
+ .getLogger(Guards.class.getName(), "jdk.dynalink.support.messages");
+
+ private Guards() {
+ }
+
+ /**
+ * Creates a guard method handle with arguments of a specified type, but with boolean return value. When invoked, it
+ * returns true if the first argument is of the specified class (exactly of it, not a subclass). The rest of the
+ * arguments will be ignored.
+ *
+ * @param clazz the class of the first argument to test for
+ * @param type the method type
+ * @return a method handle testing whether its first argument is of the specified class.
+ */
+ @SuppressWarnings("boxing")
+ public static MethodHandle isOfClass(final Class<?> clazz, final MethodType type) {
+ final Class<?> declaredType = type.parameterType(0);
+ if(clazz == declaredType) {
+ LOG.log(Level.WARNING, "isOfClassGuardAlwaysTrue", new Object[] { clazz.getName(), 0, type, DynamicLinker.getLinkedCallSiteLocation() });
+ return constantTrue(type);
+ }
+ if(!declaredType.isAssignableFrom(clazz)) {
+ LOG.log(Level.WARNING, "isOfClassGuardAlwaysFalse", new Object[] { clazz.getName(), 0, type, DynamicLinker.getLinkedCallSiteLocation() });
+ return constantFalse(type);
+ }
+ return getClassBoundArgumentTest(IS_OF_CLASS, clazz, 0, type);
+ }
+
+ /**
+ * Creates a method handle with arguments of a specified type, but with boolean return value. When invoked, it
+ * returns true if the first argument is instance of the specified class or its subclass). The rest of the arguments
+ * will be ignored.
+ *
+ * @param clazz the class of the first argument to test for
+ * @param type the method type
+ * @return a method handle testing whether its first argument is of the specified class or subclass.
+ */
+ public static MethodHandle isInstance(final Class<?> clazz, final MethodType type) {
+ return isInstance(clazz, 0, type);
+ }
+
+ /**
+ * Creates a method handle with arguments of a specified type, but with boolean return value. When invoked, it
+ * returns true if the n'th argument is instance of the specified class or its subclass). The rest of the arguments
+ * will be ignored.
+ *
+ * @param clazz the class of the first argument to test for
+ * @param pos the position on the argument list to test
+ * @param type the method type
+ * @return a method handle testing whether its first argument is of the specified class or subclass.
+ */
+ @SuppressWarnings("boxing")
+ public static MethodHandle isInstance(final Class<?> clazz, final int pos, final MethodType type) {
+ final Class<?> declaredType = type.parameterType(pos);
+ if(clazz.isAssignableFrom(declaredType)) {
+ LOG.log(Level.WARNING, "isInstanceGuardAlwaysTrue", new Object[] { clazz.getName(), pos, type, DynamicLinker.getLinkedCallSiteLocation() });
+ return constantTrue(type);
+ }
+ if(!declaredType.isAssignableFrom(clazz)) {
+ LOG.log(Level.WARNING, "isInstanceGuardAlwaysFalse", new Object[] { clazz.getName(), pos, type, DynamicLinker.getLinkedCallSiteLocation() });
+ return constantFalse(type);
+ }
+ return getClassBoundArgumentTest(IS_INSTANCE, clazz, pos, type);
+ }
+
+ /**
+ * Creates a method handle that returns true if the argument in the specified position is a Java array.
+ *
+ * @param pos the position in the argument lit
+ * @param type the method type of the handle
+ * @return a method handle that returns true if the argument in the specified position is a Java array; the rest of
+ * the arguments are ignored.
+ */
+ @SuppressWarnings("boxing")
+ public static MethodHandle isArray(final int pos, final MethodType type) {
+ final Class<?> declaredType = type.parameterType(pos);
+ if(declaredType.isArray()) {
+ LOG.log(Level.WARNING, "isArrayGuardAlwaysTrue", new Object[] { pos, type, DynamicLinker.getLinkedCallSiteLocation() });
+ return constantTrue(type);
+ }
+ if(!declaredType.isAssignableFrom(Object[].class)) {
+ LOG.log(Level.WARNING, "isArrayGuardAlwaysFalse", new Object[] { pos, type, DynamicLinker.getLinkedCallSiteLocation() });
+ return constantFalse(type);
+ }
+ return asType(IS_ARRAY, pos, type);
+ }
+
+ private static MethodHandle getClassBoundArgumentTest(final MethodHandle test, final Class<?> clazz, final int pos, final MethodType type) {
+ // Bind the class to the first argument of the test
+ return asType(test.bindTo(clazz), pos, type);
+ }
+
+ /**
+ * Takes a method handle intended to be used as a guard, and adapts it to
+ * the requested type, but returning a boolean. Applies
+ * {@link MethodHandle#asType(MethodType)} to convert types and uses
+ * {@link MethodHandles#dropArguments(MethodHandle, int, Class...)} to match
+ * the requested type arity.
+ * @param test the test method handle
+ * @param type the type to adapt the method handle to
+ * @return the adapted method handle
+ */
+ public static MethodHandle asType(final MethodHandle test, final MethodType type) {
+ return test.asType(getTestType(test, type));
+ }
+
+ /**
+ * Takes a method handle intended to be used as a guard, and adapts it to
+ * the requested type, but returning a boolean. Applies
+ * {@link LinkerServices#asType(MethodHandle, MethodType)} to convert types
+ * and uses
+ * {@link MethodHandles#dropArguments(MethodHandle, int, Class...)} to match
+ * the requested type arity.
+ * @param linkerServices the linker services to use for type conversions
+ * @param test the test method handle
+ * @param type the type to adapt the method handle to
+ * @return the adapted method handle
+ */
+ public static MethodHandle asType(final LinkerServices linkerServices, final MethodHandle test, final MethodType type) {
+ return linkerServices.asType(test, getTestType(test, type));
+ }
+
+ private static MethodType getTestType(final MethodHandle test, final MethodType type) {
+ return type.dropParameterTypes(test.type().parameterCount(),
+ type.parameterCount()).changeReturnType(boolean.class);
+ }
+
+ private static MethodHandle asType(final MethodHandle test, final int pos, final MethodType type) {
+ assert test != null;
+ assert type != null;
+ assert type.parameterCount() > 0;
+ assert pos >= 0 && pos < type.parameterCount();
+ assert test.type().parameterCount() == 1;
+ assert test.type().returnType() == Boolean.TYPE;
+ return MethodHandles.permuteArguments(test.asType(test.type().changeParameterType(0, type.parameterType(pos))),
+ type.changeReturnType(Boolean.TYPE), new int[] { pos });
+ }
+
+ private static final MethodHandle IS_INSTANCE = Lookup.PUBLIC.findVirtual(Class.class, "isInstance",
+ MethodType.methodType(Boolean.TYPE, Object.class));
+
+ private static final MethodHandle IS_OF_CLASS;
+ private static final MethodHandle IS_ARRAY;
+ private static final MethodHandle IS_IDENTICAL;
+ private static final MethodHandle IS_NULL;
+ private static final MethodHandle IS_NOT_NULL;
+
+ static {
+ final Lookup lookup = new Lookup(MethodHandles.lookup());
+
+ IS_OF_CLASS = lookup.findOwnStatic("isOfClass", Boolean.TYPE, Class.class, Object.class);
+ IS_ARRAY = lookup.findOwnStatic("isArray", Boolean.TYPE, Object.class);
+ IS_IDENTICAL = lookup.findOwnStatic("isIdentical", Boolean.TYPE, Object.class, Object.class);
+ IS_NULL = lookup.findOwnStatic("isNull", Boolean.TYPE, Object.class);
+ IS_NOT_NULL = lookup.findOwnStatic("isNotNull", Boolean.TYPE, Object.class);
+ }
+
+ /**
+ * Creates a guard method that tests its only argument for being of an exact particular class.
+ * @param clazz the class to test for.
+ * @return the desired guard method.
+ */
+ public static MethodHandle getClassGuard(final Class<?> clazz) {
+ return IS_OF_CLASS.bindTo(clazz);
+ }
+
+ /**
+ * Creates a guard method that tests its only argument for being an instance of a particular class.
+ * @param clazz the class to test for.
+ * @return the desired guard method.
+ */
+ public static MethodHandle getInstanceOfGuard(final Class<?> clazz) {
+ return IS_INSTANCE.bindTo(clazz);
+ }
+
+ /**
+ * Creates a guard method that tests its only argument for being referentially identical to another object
+ * @param obj the object used as referential identity test
+ * @return the desired guard method.
+ */
+ public static MethodHandle getIdentityGuard(final Object obj) {
+ return IS_IDENTICAL.bindTo(obj);
+ }
+
+ /**
+ * Returns a guard that tests whether the first argument is null.
+ * @return a guard that tests whether the first argument is null.
+ */
+ public static MethodHandle isNull() {
+ return IS_NULL;
+ }
+
+ /**
+ * Returns a guard that tests whether the first argument is not null.
+ * @return a guard that tests whether the first argument is not null.
+ */
+ public static MethodHandle isNotNull() {
+ return IS_NOT_NULL;
+ }
+
+ @SuppressWarnings("unused")
+ private static boolean isNull(final Object obj) {
+ return obj == null;
+ }
+
+ @SuppressWarnings("unused")
+ private static boolean isNotNull(final Object obj) {
+ return obj != null;
+ }
+
+ @SuppressWarnings("unused")
+ private static boolean isArray(final Object o) {
+ return o != null && o.getClass().isArray();
+ }
+
+ @SuppressWarnings("unused")
+ private static boolean isOfClass(final Class<?> c, final Object o) {
+ return o != null && o.getClass() == c;
+ }
+
+ @SuppressWarnings("unused")
+ private static boolean isIdentical(final Object o1, final Object o2) {
+ return o1 == o2;
+ }
+
+ private static MethodHandle constantTrue(final MethodType type) {
+ return constantBoolean(Boolean.TRUE, type);
+ }
+
+ private static MethodHandle constantFalse(final MethodType type) {
+ return constantBoolean(Boolean.FALSE, type);
+ }
+
+ private static MethodHandle constantBoolean(final Boolean value, final MethodType type) {
+ return MethodHandles.permuteArguments(MethodHandles.constant(Boolean.TYPE, value),
+ type.changeReturnType(Boolean.TYPE));
+ }
+}