--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/src/jdk.dynalink/share/classes/jdk/dynalink/beans/SingleDynamicMethod.java Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,311 @@
+/*
+ * 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.beans;
+
+import java.lang.invoke.MethodHandle;
+import java.lang.invoke.MethodHandles;
+import java.lang.invoke.MethodType;
+import java.lang.reflect.Array;
+import java.util.StringTokenizer;
+import jdk.dynalink.CallSiteDescriptor;
+import jdk.dynalink.linker.LinkerServices;
+import jdk.dynalink.linker.support.Guards;
+import jdk.dynalink.linker.support.Lookup;
+
+/**
+ * Base class for dynamic methods that dispatch to a single target Java method or constructor. Handles adaptation of the
+ * target method to a call site type (including mapping variable arity methods to a call site signature with different
+ * arity).
+ */
+abstract class SingleDynamicMethod extends DynamicMethod {
+ private static final MethodHandle CAN_CONVERT_TO = Lookup.findOwnStatic(MethodHandles.lookup(), "canConvertTo", boolean.class, LinkerServices.class, Class.class, Object.class);
+
+ SingleDynamicMethod(final String name) {
+ super(name);
+ }
+
+ /**
+ * Returns true if this method is variable arity.
+ * @return true if this method is variable arity.
+ */
+ abstract boolean isVarArgs();
+
+ /**
+ * Returns this method's native type.
+ * @return this method's native type.
+ */
+ abstract MethodType getMethodType();
+
+ /**
+ * Given a specified call site descriptor, returns a method handle to this method's target. The target
+ * should only depend on the descriptor's lookup, and it should only retrieve it (as a privileged
+ * operation) when it is absolutely needed.
+ * @param desc the call site descriptor to use.
+ * @return the handle to this method's target method.
+ */
+ abstract MethodHandle getTarget(CallSiteDescriptor desc);
+
+ @Override
+ MethodHandle getInvocation(final CallSiteDescriptor callSiteDescriptor, final LinkerServices linkerServices) {
+ return linkerServices.getWithLookup(()->getInvocation(getTarget(callSiteDescriptor),
+ callSiteDescriptor.getMethodType(), linkerServices), callSiteDescriptor);
+ }
+
+ @Override
+ SingleDynamicMethod getMethodForExactParamTypes(final String paramTypes) {
+ return typeMatchesDescription(paramTypes, getMethodType()) ? this : null;
+ }
+
+ @Override
+ boolean contains(final SingleDynamicMethod method) {
+ return getMethodType().parameterList().equals(method.getMethodType().parameterList());
+ }
+
+ static String getMethodNameWithSignature(final MethodType type, final String methodName, final boolean withReturnType) {
+ final String typeStr = type.toString();
+ final int retTypeIndex = typeStr.lastIndexOf(')') + 1;
+ int secondParamIndex = typeStr.indexOf(',') + 1;
+ if(secondParamIndex == 0) {
+ secondParamIndex = retTypeIndex - 1;
+ }
+ final StringBuilder b = new StringBuilder();
+ if (withReturnType) {
+ b.append(typeStr, retTypeIndex, typeStr.length()).append(' ');
+ }
+ return b.append(methodName).append('(').append(typeStr, secondParamIndex, retTypeIndex).toString();
+ }
+
+ /**
+ * Given a method handle and a call site type, adapts the method handle to the call site type. Performs type
+ * conversions as needed using the specified linker services, and in case that the method handle is a vararg
+ * collector, matches it to the arity of the call site. The type of the return value is only changed if it can be
+ * converted using a conversion that loses neither precision nor magnitude, see
+ * {@link LinkerServices#asTypeLosslessReturn(MethodHandle, MethodType)}.
+ * @param target the method handle to adapt
+ * @param callSiteType the type of the call site
+ * @param linkerServices the linker services used for type conversions
+ * @return the adapted method handle.
+ */
+ static MethodHandle getInvocation(final MethodHandle target, final MethodType callSiteType, final LinkerServices linkerServices) {
+ final MethodHandle filteredTarget = linkerServices.filterInternalObjects(target);
+ final MethodType methodType = filteredTarget.type();
+ final int paramsLen = methodType.parameterCount();
+ final boolean varArgs = target.isVarargsCollector();
+ final MethodHandle fixTarget = varArgs ? filteredTarget.asFixedArity() : filteredTarget;
+ final int fixParamsLen = varArgs ? paramsLen - 1 : paramsLen;
+ final int argsLen = callSiteType.parameterCount();
+ if(argsLen < fixParamsLen) {
+ // Less actual arguments than number of fixed declared arguments; can't invoke.
+ return null;
+ }
+ // Method handle has the same number of fixed arguments as the call site type
+ if(argsLen == fixParamsLen) {
+ // Method handle that matches the number of actual arguments as the number of fixed arguments
+ final MethodHandle matchedMethod;
+ if(varArgs) {
+ // If vararg, add a zero-length array of the expected type as the last argument to signify no variable
+ // arguments.
+ matchedMethod = MethodHandles.insertArguments(fixTarget, fixParamsLen, Array.newInstance(
+ methodType.parameterType(fixParamsLen).getComponentType(), 0));
+ } else {
+ // Otherwise, just use the method
+ matchedMethod = fixTarget;
+ }
+ return createConvertingInvocation(matchedMethod, linkerServices, callSiteType);
+ }
+
+ // What's below only works for varargs
+ if(!varArgs) {
+ return null;
+ }
+
+ final Class<?> varArgType = methodType.parameterType(fixParamsLen);
+ // Handle a somewhat sinister corner case: caller passes exactly one argument in the vararg position, and we
+ // must handle both a prepacked vararg array as well as a genuine 1-long vararg sequence.
+ if(argsLen == paramsLen) {
+ final Class<?> callSiteLastArgType = callSiteType.parameterType(fixParamsLen);
+ if(varArgType.isAssignableFrom(callSiteLastArgType)) {
+ // Call site signature guarantees we'll always be passed a single compatible array; just link directly
+ // to the method, introducing necessary conversions. Also, preserve it being a variable arity method.
+ return createConvertingInvocation(filteredTarget, linkerServices, callSiteType).asVarargsCollector(
+ callSiteLastArgType);
+ }
+
+ // This method handle takes the single argument and packs it into a newly allocated single-element array. It
+ // will be used when the incoming argument can't be converted to the vararg array type (the "vararg packer"
+ // method).
+ final MethodHandle varArgCollectingInvocation = createConvertingInvocation(collectArguments(fixTarget,
+ argsLen), linkerServices, callSiteType);
+
+ // Is call site type assignable from an array type (e.g. Object:int[], or Object[]:String[])
+ final boolean isAssignableFromArray = callSiteLastArgType.isAssignableFrom(varArgType);
+ // Do we have a custom conversion that can potentially convert the call site type to an array?
+ final boolean isCustomConvertible = linkerServices.canConvert(callSiteLastArgType, varArgType);
+ if(!isAssignableFromArray && !isCustomConvertible) {
+ // Call site signature guarantees the argument can definitely not be converted to an array (i.e. it is
+ // primitive), and no conversion can help with it either. Link immediately to a vararg-packing method
+ // handle.
+ return varArgCollectingInvocation;
+ }
+
+ // This method handle employs language-specific conversions to convert the last argument into an array of
+ // vararg type.
+ final MethodHandle arrayConvertingInvocation = createConvertingInvocation(MethodHandles.filterArguments(
+ fixTarget, fixParamsLen, linkerServices.getTypeConverter(callSiteLastArgType, varArgType)),
+ linkerServices, callSiteType);
+
+ // This method handle determines whether the value can be converted to the array of vararg type using a
+ // language-specific conversion.
+ final MethodHandle canConvertArgToArray = MethodHandles.insertArguments(CAN_CONVERT_TO, 0, linkerServices,
+ varArgType);
+
+ // This one adjusts the previous one for the location of the argument and the call site type.
+ final MethodHandle canConvertLastArgToArray = MethodHandles.dropArguments(canConvertArgToArray, 0,
+ MethodType.genericMethodType(fixParamsLen).parameterList()).asType(callSiteType.changeReturnType(boolean.class));
+
+ // This one takes the previous ones and combines them into a method handle that converts the argument into
+ // a vararg array when it can, otherwise falls back to the vararg packer.
+ final MethodHandle convertToArrayWhenPossible = MethodHandles.guardWithTest(canConvertLastArgToArray,
+ arrayConvertingInvocation, varArgCollectingInvocation);
+
+ if(isAssignableFromArray) {
+ return MethodHandles.guardWithTest(
+ // Is incoming parameter already a compatible array?
+ Guards.isInstance(varArgType, fixParamsLen, callSiteType),
+ // Yes: just pass it to the method
+ createConvertingInvocation(fixTarget, linkerServices, callSiteType),
+ // No: either go through a custom conversion, or if it is not possible, go directly to the
+ // vararg packer.
+ isCustomConvertible ? convertToArrayWhenPossible : varArgCollectingInvocation);
+ }
+
+ // Just do the custom conversion with fallback to the vararg packer logic.
+ assert isCustomConvertible;
+ return convertToArrayWhenPossible;
+ }
+
+ // Remaining case: more than one vararg.
+ return createConvertingInvocation(collectArguments(fixTarget, argsLen), linkerServices, callSiteType);
+ }
+
+ @SuppressWarnings("unused")
+ private static boolean canConvertTo(final LinkerServices linkerServices, final Class<?> to, final Object obj) {
+ return obj == null ? false : linkerServices.canConvert(obj.getClass(), to);
+ }
+
+ /**
+ * Creates a method handle out of the original target that will collect the varargs for the exact component type of
+ * the varArg array. Note that this will nicely trigger language-specific type converters for exactly those varargs
+ * for which it is necessary when later passed to linkerServices.convertArguments().
+ *
+ * @param target the original method handle
+ * @param parameterCount the total number of arguments in the new method handle
+ * @return a collecting method handle
+ */
+ static MethodHandle collectArguments(final MethodHandle target, final int parameterCount) {
+ final MethodType methodType = target.type();
+ final int fixParamsLen = methodType.parameterCount() - 1;
+ final Class<?> arrayType = methodType.parameterType(fixParamsLen);
+ return target.asCollector(arrayType, parameterCount - fixParamsLen);
+ }
+
+ private static MethodHandle createConvertingInvocation(final MethodHandle sizedMethod,
+ final LinkerServices linkerServices, final MethodType callSiteType) {
+ return linkerServices.asTypeLosslessReturn(sizedMethod, callSiteType);
+ }
+
+ private static boolean typeMatchesDescription(final String paramTypes, final MethodType type) {
+ final StringTokenizer tok = new StringTokenizer(paramTypes, ", ");
+ for(int i = 1; i < type.parameterCount(); ++i) { // i = 1 as we ignore the receiver
+ if(!(tok.hasMoreTokens() && typeNameMatches(tok.nextToken(), type.parameterType(i)))) {
+ return false;
+ }
+ }
+ return !tok.hasMoreTokens();
+ }
+
+ private static boolean typeNameMatches(final String typeName, final Class<?> type) {
+ return typeName.equals(typeName.indexOf('.') == -1 ? type.getSimpleName() : type.getCanonicalName());
+ }
+}