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1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one
3    * or more contributor license agreements.  See the NOTICE file
4    * distributed with this work for additional information
5    * regarding copyright ownership.  The ASF licenses this file
6    * to you under the Apache License, Version 2.0 (the
7    * "License"); you may not use this file except in compliance
8    * with the License.  You may obtain a copy of the License at
9    *
10   *   https://www.apache.org/licenses/LICENSE-2.0
11   *
12   * Unless required by applicable law or agreed to in writing,
13   * software distributed under the License is distributed on an
14   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15   * KIND, either express or implied.  See the License for the
16   * specific language governing permissions and limitations
17   * under the License.
18   */
19  package org.apache.bcel.generic;
20  
21  import java.io.DataOutputStream;
22  import java.io.IOException;
23  
24  import org.apache.bcel.Const;
25  import org.apache.bcel.ExceptionConst;
26  import org.apache.bcel.classfile.ConstantInvokeDynamic;
27  import org.apache.bcel.classfile.ConstantNameAndType;
28  import org.apache.bcel.classfile.ConstantPool;
29  import org.apache.bcel.util.ByteSequence;
30  
31  /**
32   * Class for INVOKEDYNAMIC. Not an instance of InvokeInstruction, since that class expects to be able to get the class
33   * of the method. Ignores the bootstrap mechanism entirely.
34   *
35   * @see <a href="https://docs.oracle.com/javase/specs/jvms/se8/html/jvms-6.html#jvms-6.5.invokedynamic"> The
36   *      invokedynamic instruction in The Java Virtual Machine Specification</a>
37   * @since 6.0
38   */
39  public class INVOKEDYNAMIC extends InvokeInstruction {
40  
41      /**
42       * Empty constructor needed for Instruction.readInstruction. Not to be used otherwise.
43       */
44      INVOKEDYNAMIC() {
45      }
46  
47      public INVOKEDYNAMIC(final int index) {
48          super(Const.INVOKEDYNAMIC, index);
49      }
50  
51      /**
52       * Call corresponding visitor method(s). The order is: Call visitor methods of implemented interfaces first, then call
53       * methods according to the class hierarchy in descending order, i.e., the most specific visitXXX() call comes last.
54       *
55       * @param v Visitor object
56       */
57      @Override
58      public void accept(final Visitor v) {
59          v.visitExceptionThrower(this);
60          v.visitTypedInstruction(this);
61          v.visitStackConsumer(this);
62          v.visitStackProducer(this);
63          v.visitLoadClass(this);
64          v.visitCPInstruction(this);
65          v.visitFieldOrMethod(this);
66          v.visitInvokeInstruction(this);
67          v.visitINVOKEDYNAMIC(this);
68      }
69  
70      /**
71       * Dump instruction as byte code to stream out.
72       *
73       * @param out Output stream
74       */
75      @Override
76      public void dump(final DataOutputStream out) throws IOException {
77          out.writeByte(super.getOpcode());
78          out.writeShort(super.getIndex());
79          out.writeByte(0);
80          out.writeByte(0);
81      }
82  
83      /**
84       * Override the parent method because our class name is held elsewhere.
85       *
86       * Note: Contrary to this method's name it does not return the class name of the invoke target; rather it returns the
87       * name of the method that will be used to invoke the Lambda method generated by this invoke dynamic instruction.
88       */
89      @Override
90      public String getClassName(final ConstantPoolGen cpg) {
91          final ConstantPool cp = cpg.getConstantPool();
92          final ConstantInvokeDynamic cid = cp.getConstant(super.getIndex(), Const.CONSTANT_InvokeDynamic, ConstantInvokeDynamic.class);
93          return cp.getConstant(cid.getNameAndTypeIndex(), ConstantNameAndType.class).getName(cp);
94      }
95  
96      @Override
97      public Class<?>[] getExceptions() {
98          return ExceptionConst.createExceptions(ExceptionConst.EXCS.EXCS_INTERFACE_METHOD_RESOLUTION, ExceptionConst.UNSATISFIED_LINK_ERROR,
99              ExceptionConst.ABSTRACT_METHOD_ERROR, ExceptionConst.ILLEGAL_ACCESS_ERROR, ExceptionConst.INCOMPATIBLE_CLASS_CHANGE_ERROR);
100     }
101 
102     /**
103      * Since InvokeDynamic doesn't refer to a reference type, just return {@link Object}, as that is the only type we can
104      * say for sure the reference will be.
105      *
106      * @param cpg the ConstantPoolGen used to create the instruction
107      * @return an ObjectType for {@link Object}
108      * @since 6.1
109      */
110     @Override
111     public ReferenceType getReferenceType(final ConstantPoolGen cpg) {
112         return new ObjectType(Object.class.getName());
113     }
114 
115     /**
116      * Reads needed data (i.e., index) from file.
117      */
118     @Override
119     protected void initFromFile(final ByteSequence bytes, final boolean wide) throws IOException {
120         super.initFromFile(bytes, wide);
121         super.setLength(5);
122         bytes.readByte(); // Skip 0 byte
123         bytes.readByte(); // Skip 0 byte
124     }
125 
126 }