jdk8-mips64-public/nashorn: src/jdk/nashorn/internal/ir/ReturnNode.java@4be452026847

8010652: Eliminate non-child references in Block/FunctionNode, and make few node types immutable
Reviewed-by: jlaskey, lagergren

     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  */

    26 package jdk.nashorn.internal.ir;

    28 import static jdk.nashorn.internal.parser.TokenType.RETURN;

    29 import static jdk.nashorn.internal.parser.TokenType.YIELD;

    31 import jdk.nashorn.internal.ir.annotations.Ignore;

    32 import jdk.nashorn.internal.ir.visitor.NodeVisitor;

    33 import jdk.nashorn.internal.runtime.Source;

    35 /**

    36  * IR representation for RETURN or YIELD statements.

    37  *

    38  */

    39 public class ReturnNode extends Node {

    40     /** Optional expression. */

    41     private Node expression;

    43     /** Try chain. */

    44     @Ignore

    45     private final TryNode tryChain;

    47     /**

    48      * Constructor

    49      *

    50      * @param source     the source

    51      * @param token      token

    52      * @param finish     finish

    53      * @param expression expression to return

    54      * @param tryChain   surrounding try chain.

    55      */

    56     public ReturnNode(final Source source, final long token, final int finish, final Node expression, final TryNode tryChain) {

    57         super(source, token, finish);

    59         this.expression = expression;

    60         this.tryChain   = tryChain;

    62         setIsTerminal(true);

    63     }

    65     private ReturnNode(final ReturnNode returnNode, final CopyState cs) {

    66         super(returnNode);

    68         this.expression = cs.existingOrCopy(returnNode.expression);

    69         this.tryChain   = (TryNode)cs.existingOrSame(returnNode.tryChain);

    70     }

    72     @Override

    73     protected Node copy(final CopyState cs) {

    74         return new ReturnNode(this, cs);

    75     }

    77     /**

    78      * Return true if is a RETURN node.

    79      * @return true if is RETURN node.

    80      */

    81     public boolean isReturn() {

    82         return isTokenType(RETURN);

    83     }

    85     /**

    86      * Check if this return node has an expression

    87      * @return true if not a void return

    88      */

    89     public boolean hasExpression() {

    90         return expression != null;

    91     }

    93     /**

    94      * Return true if is a YIELD node.

    95      * @return TRUE if is YIELD node.

    96      */

    97     public boolean isYield() {

    98         return isTokenType(YIELD);

    99     }

   101     @Override

   102     public Node accept(final NodeVisitor visitor) {

   103         if (visitor.enterReturnNode(this) != null) {

   104             if (expression != null) {

   105                 expression = expression.accept(visitor);

   106             }

   108             return visitor.leaveReturnNode(this);

   109         }

   111         return this;

   112     }

   115     @Override

   116     public void toString(final StringBuilder sb) {

   117         sb.append(isYield() ? "yield" : "return ");

   119         if (expression != null) {

   120             expression.toString(sb);

   121         }

   122     }

   124     @Override

   125     public boolean equals(final Object other) {

   126         if (other instanceof ReturnNode) {

   127             final ReturnNode otherReturn = (ReturnNode)other;

   128             if (hasExpression() != otherReturn.hasExpression()) {

   129                 return false;

   130             } else if (hasExpression()) {

   131                 return otherReturn.getExpression().equals(getExpression());

   132             }

   133             return true;

   134         }

   135         return false;

   136     }

   138     @Override

   139     public int hashCode() {

   140         return 0x4711_17 ^ (expression == null ? 0 : expression.hashCode());

   141     }

   143     /**

   144      * Get the expression this node returns

   145      * @return return expression, or null if void return

   146      */

   147     public Node getExpression() {

   148         return expression;

   149     }

   151     /**

   152      * Reset the expression this node returns

   153      * @param expression new expression, or null if void return

   154      */

   155     public void setExpression(final Node expression) {

   156         this.expression = expression;

   157     }

   159     /**

   160      * Get the surrounding try chain for this return node

   161      * @return try chain

   162      */

   163     public TryNode getTryChain() {

   164         return tryChain;

   165     }

   166 }

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