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 /*

    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 2009-2013 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 

    84 package jdk.internal.dynalink.support;

    85 

    86 import java.lang.invoke.MethodHandles;

    87 import java.lang.invoke.MethodHandles.Lookup;

    88 import java.lang.invoke.MethodType;

    89 import java.lang.ref.WeakReference;

    90 import java.util.Arrays;

    91 import java.util.Collections;

    92 import java.util.List;

    93 import java.util.StringTokenizer;

    94 import java.util.WeakHashMap;

    95 import jdk.internal.dynalink.CallSiteDescriptor;

    96 

    97 

    98 /**

    99  * Usable as a default factory for call site descriptor implementations. It is weakly canonicalizing, meaning it will

   100  * return the same immutable call site descriptor for identical inputs, i.e. repeated requests for a descriptor

   101  * signifying public lookup for "dyn:getProp:color" of type "Object(Object)" will return the same object as long as

   102  * a previously created, at least softly reachable one exists. It also uses several different implementations of the

   103  * {@link CallSiteDescriptor} internally, and chooses the most space-efficient one based on the input.

   104  * @author Attila Szegedi

   105  */

   106 public class CallSiteDescriptorFactory {

   107     private static final WeakHashMap<CallSiteDescriptor, WeakReference<CallSiteDescriptor>> publicDescs =

   108             new WeakHashMap<>();

   109 

   110 

   111     private CallSiteDescriptorFactory() {

   112     }

   113 

   114     /**

   115      * Creates a new call site descriptor instance. The actual underlying class of the instance is dependent on the

   116      * passed arguments to be space efficient; i.e. if you  only use the public lookup, you'll get back an

   117      * implementation that doesn't waste space on storing the lookup object.

   118      * @param lookup the lookup that determines access rights at the call site. If your language runtime doesn't have

   119      * equivalents of Java access concepts, just use {@link MethodHandles#publicLookup()}. Must not be null.

   120      * @param name the name of the method at the call site. Must not be null.

   121      * @param methodType the type of the method at the call site. Must not be null.

   122      * @return a call site descriptor representing the input. Note that although the method name is "create", it will

   123      * in fact return a weakly-referenced canonical instance.

   124      */

   125     public static CallSiteDescriptor create(Lookup lookup, String name, MethodType methodType) {

   126         name.getClass(); // NPE check

   127         methodType.getClass(); // NPE check

   128         lookup.getClass(); // NPE check

   129         final String[] tokenizedName = tokenizeName(name);

   130         if(isPublicLookup(lookup)) {

   131             return getCanonicalPublicDescriptor(createPublicCallSiteDescriptor(tokenizedName, methodType));

   132         } else {

   133             return new LookupCallSiteDescriptor(tokenizedName, methodType, lookup);

   134         }

   135     }

   136 

   137     static CallSiteDescriptor getCanonicalPublicDescriptor(final CallSiteDescriptor desc) {

   138         synchronized(publicDescs) {

   139             final WeakReference<CallSiteDescriptor> ref = publicDescs.get(desc);

   140             if(ref != null) {

   141                 final CallSiteDescriptor canonical = ref.get();

   142                 if(canonical != null) {

   143                     return canonical;

   144                 }

   145             }

   146             publicDescs.put(desc, new WeakReference<>(desc));

   147         }

   148         return desc;

   149     }

   150 

   151     private static CallSiteDescriptor createPublicCallSiteDescriptor(String[] tokenizedName, MethodType methodType) {

   152         final int l = tokenizedName.length;

   153         if(l > 0 && tokenizedName[0] == "dyn") {

   154             if(l == 2) {

   155                 return new UnnamedDynCallSiteDescriptor(tokenizedName[1], methodType);

   156             } if (l == 3) {

   157                 return new NamedDynCallSiteDescriptor(tokenizedName[1], tokenizedName[2], methodType);

   158             }

   159         }

   160         return new DefaultCallSiteDescriptor(tokenizedName, methodType);

   161     }

   162 

   163     private static boolean isPublicLookup(Lookup lookup) {

   164         return lookup == MethodHandles.publicLookup();

   165     }

   166 

   167     /**

   168      * Tokenizes the composite name along colons, as well as {@link NameCodec#decode(String) demangles} and interns

   169      * the tokens. The first two tokens are not demangled as they are supposed to be the naming scheme and the name of

   170      * the operation which can be expected to consist of just alphabetical characters.

   171      * @param name the composite name consisting of colon-separated, possibly mangled tokens.

   172      * @return an array of tokens

   173      */

   174     public static String[] tokenizeName(String name) {

   175         final StringTokenizer tok = new StringTokenizer(name, CallSiteDescriptor.TOKEN_DELIMITER);

   176         final String[] tokens = new String[tok.countTokens()];

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

   178             String token = tok.nextToken();

   179             if(i > 1) {

   180                 token = NameCodec.decode(token);

   181             }

   182             tokens[i] = token.intern();

   183         }

   184         return tokens;

   185     }

   186 

   187     /**

   188      * Tokenizes a composite operation name along pipe characters. I.e. if you have a "dyn:getElem|getProp|getMethod"

   189      * operation, returns a list of ["getElem", "getProp", "getMethod"]. The tokens are not interned.

   190      * @param desc the call site descriptor with the operation

   191      * @return a list of tokens

   192      */

   193     public static List<String> tokenizeOperators(CallSiteDescriptor desc) {

   194         final String ops = desc.getNameToken(CallSiteDescriptor.OPERATOR);

   195         final StringTokenizer tok = new StringTokenizer(ops, CallSiteDescriptor.OPERATOR_DELIMITER);

   196         final int count = tok.countTokens();

   197         if(count == 1) {

   198             return Collections.singletonList(ops);

   199         }

   200         final String[] tokens = new String[count];

   201         for(int i = 0; i < count; ++i) {

   202             tokens[i] = tok.nextToken();

   203         }

   204         return Arrays.asList(tokens);

   205     }

   206 

   207     /**

   208      * Returns a new call site descriptor that is identical to the passed one, except that it has some parameter types

   209      * removed from its method type.

   210      * @param desc the original call site descriptor

   211      * @param start index of the first parameter to remove

   212      * @param end index of the first parameter to not remove

   213      * @return a new call site descriptor with modified method type

   214      */

   215     public static CallSiteDescriptor dropParameterTypes(CallSiteDescriptor desc, int start, int end) {

   216         return desc.changeMethodType(desc.getMethodType().dropParameterTypes(start, end));

   217     }

   218 

   219     /**

   220      * Returns a new call site descriptor that is identical to the passed one, except that it has a single parameter

   221      * type changed in its method type.

   222      * @param desc the original call site descriptor

   223      * @param num index of the parameter to change

   224      * @param nptype the new parameter type

   225      * @return a new call site descriptor with modified method type

   226      */

   227     public static CallSiteDescriptor changeParameterType(CallSiteDescriptor desc, int num, Class<?> nptype) {

   228         return desc.changeMethodType(desc.getMethodType().changeParameterType(num, nptype));

   229     }

   230 

   231     /**

   232      * Returns a new call site descriptor that is identical to the passed one, except that it has the return type

   233      * changed in its method type.

   234      * @param desc the original call site descriptor

   235      * @param nrtype the new return type

   236      * @return a new call site descriptor with modified method type

   237      */

   238     public static CallSiteDescriptor changeReturnType(CallSiteDescriptor desc, Class<?> nrtype) {

   239         return desc.changeMethodType(desc.getMethodType().changeReturnType(nrtype));

   240     }

   241 

   242     /**

   243      * Returns a new call site descriptor that is identical to the passed one, except that it has additional parameter

   244      * types inserted into its method type.

   245      * @param desc the original call site descriptor

   246      * @param num index at which the new parameters are inserted

   247      * @param ptypesToInsert the new types to insert

   248      * @return a new call site descriptor with modified method type

   249      */

   250     public static CallSiteDescriptor insertParameterTypes(CallSiteDescriptor desc, int num, Class<?>... ptypesToInsert) {

   251         return desc.changeMethodType(desc.getMethodType().insertParameterTypes(num, ptypesToInsert));

   252     }

   253 

   254     /**

   255      * Returns a new call site descriptor that is identical to the passed one, except that it has additional parameter

   256      * types inserted into its method type.

   257      * @param desc the original call site descriptor

   258      * @param num index at which the new parameters are inserted

   259      * @param ptypesToInsert the new types to insert

   260      * @return a new call site descriptor with modified method type

   261      */

   262     public static CallSiteDescriptor insertParameterTypes(CallSiteDescriptor desc, int num, List<Class<?>> ptypesToInsert) {

   263         return desc.changeMethodType(desc.getMethodType().insertParameterTypes(num, ptypesToInsert));

   264     }

   265 }