Mercurial > jdk8-mips64-public > nashorn / file revision

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  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

  *

  * This code is free software; you can redistribute it and/or modify it

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  * 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

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 /*

  * 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 2009-2015 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.internal.dynalink.support;

 import java.lang.invoke.MethodHandle;

 import java.lang.invoke.MethodHandles;

 import java.lang.invoke.MethodType;

 import jdk.internal.dynalink.DynamicLinkerFactory;

 import jdk.internal.dynalink.linker.MethodHandleTransformer;

 /**

  * Default implementation for a {@link DynamicLinkerFactory#setInternalObjectsFilter(MethodHandleTransformer)}.

  * Given a method handle of {@code Object(Object)} type for filtering parameter and another one of the same type for

  * filtering return values, applies them to passed method handles where their parameter types and/or return value types

  * are declared to be {@link Object}.

  */

 public class DefaultInternalObjectFilter implements MethodHandleTransformer {

     private static final MethodHandle FILTER_VARARGS = new Lookup(MethodHandles.lookup()).findStatic(

             DefaultInternalObjectFilter.class, "filterVarArgs", MethodType.methodType(Object[].class, MethodHandle.class, Object[].class));

     private final MethodHandle parameterFilter;

     private final MethodHandle returnFilter;

     private final MethodHandle varArgFilter;

     /**

      * Creates a new filter.

      * @param parameterFilter the filter for method parameters. Must be of type {@code Object(Object)}, or null.

      * @param returnFilter the filter for return values. Must be of type {@code Object(Object)}, or null.

      * @throws IllegalArgumentException if one or both filters are not of the expected type.

      */

     public DefaultInternalObjectFilter(final MethodHandle parameterFilter, final MethodHandle returnFilter) {

         this.parameterFilter = checkHandle(parameterFilter, "parameterFilter");

         this.returnFilter = checkHandle(returnFilter, "returnFilter");

         this.varArgFilter = parameterFilter == null ? null : FILTER_VARARGS.bindTo(parameterFilter);

     }

     @Override

     public MethodHandle transform(final MethodHandle target) {

         assert target != null;

         MethodHandle[] filters = null;

         final MethodType type = target.type();

         final boolean isVarArg = target.isVarargsCollector();

         final int paramCount = type.parameterCount();

         final MethodHandle paramsFiltered;

         // Filter parameters

         if (parameterFilter != null) {

             int firstFilter = -1;

             // Ignore receiver, start from argument 1

             for(int i = 1; i < paramCount; ++i) {

                 final Class<?> paramType = type.parameterType(i);

                 final boolean filterVarArg = isVarArg && i == paramCount - 1 && paramType == Object[].class;

                 if (filterVarArg || paramType == Object.class) {

                     if (filters == null) {

                         firstFilter = i;

                         filters = new MethodHandle[paramCount - firstFilter];

                     }

                     filters[i - firstFilter] = filterVarArg ? varArgFilter : parameterFilter;

                 }

             }

             paramsFiltered = filters != null ? MethodHandles.filterArguments(target, firstFilter, filters) : target;

         } else {

             paramsFiltered = target;

         }

         // Filter return value if needed

         final MethodHandle returnFiltered = returnFilter != null && type.returnType() == Object.class ? MethodHandles.filterReturnValue(paramsFiltered, returnFilter) : paramsFiltered;

         // Preserve varargs collector state

         return isVarArg && !returnFiltered.isVarargsCollector() ? returnFiltered.asVarargsCollector(type.parameterType(paramCount - 1)) : returnFiltered;

     }

     private static MethodHandle checkHandle(final MethodHandle handle, final String handleKind) {

         if (handle != null) {

             final MethodType objectObjectType = MethodType.methodType(Object.class, Object.class);

             if (!handle.type().equals(objectObjectType)) {

                 throw new IllegalArgumentException("Method type for " + handleKind + " must be " + objectObjectType);

             }

         }

         return handle;

     }

     @SuppressWarnings("unused")

     private static Object[] filterVarArgs(final MethodHandle parameterFilter, final Object[] args) throws Throwable {

         Object[] newArgs = null;

         for(int i = 0; i < args.length; ++i) {

             final Object arg = args[i];

             final Object newArg = parameterFilter.invokeExact(arg);

             if (arg != newArg) {

                 if (newArgs == null) {

                     newArgs = args.clone();

                 }

                 newArgs[i] = newArg;

             }

         }

         return newArgs == null ? args : newArgs;

     }

 }