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 package jdk.nashorn.internal.ir;
  27 
  28 import java.util.Collections;
  29 import java.util.List;
  30 import jdk.nashorn.internal.codegen.Label;
  31 import jdk.nashorn.internal.ir.annotations.Immutable;
  32 
  33 @Immutable
  34 abstract class BreakableStatement extends LexicalContextStatement implements BreakableNode {
  35     private static final long serialVersionUID = 1L;
  36 
  37     /** break label. */
  38     protected final Label breakLabel;
  39 
  40     final LocalVariableConversion conversion;
  41 
  42     /**
  43      * Constructor
  44      *
  45      * @param lineNumber line number
  46      * @param token      token
  47      * @param finish     finish
  48      * @param breakLabel break label
  49      */
  50     protected BreakableStatement(final int lineNumber, final long token, final int finish, final Label breakLabel) {
  51         super(lineNumber, token, finish);
  52         this.breakLabel = breakLabel;
  53         this.conversion = null;
  54     }
  55 
  56     /**
  57      * Copy constructor
  58      *
  59      * @param breakableNode source node
  60      * @param conversion the potentially new local variable conversion
  61      */
  62     protected BreakableStatement(final BreakableStatement breakableNode, final LocalVariableConversion conversion) {
  63         super(breakableNode);
  64         this.breakLabel = new Label(breakableNode.getBreakLabel());
  65         this.conversion = conversion;
  66     }
  67 
  68     /**
  69      * Check whether this can be broken out from without using a label,
  70      * e.g. everything but Blocks, basically
  71      * @return true if breakable without label
  72      */
  73     @Override
  74     public boolean isBreakableWithoutLabel() {
  75         return true;
  76     }
  77 
  78     /**
  79      * Return the break label, i.e. the location to go to on break.
  80      * @return the break label
  81      */
  82     @Override
  83     public Label getBreakLabel() {
  84         return breakLabel;
  85     }
  86 
  87     /**
  88      * Return the labels associated with this node. Breakable nodes that
  89      * aren't LoopNodes only have a break label - the location immediately
  90      * afterwards the node in code
  91      * @return list of labels representing locations around this node
  92      */
  93     @Override
  94     public List<Label> getLabels() {
  95         return Collections.unmodifiableList(Collections.singletonList(breakLabel));
  96     }
  97 
  98     @Override
  99     public JoinPredecessor setLocalVariableConversion(final LexicalContext lc, final LocalVariableConversion conversion) {
 100         if(this.conversion == conversion) {
 101             return this;
 102         }
 103         return setLocalVariableConversionChanged(lc, conversion);
 104     }
 105 
 106     @Override
 107     public LocalVariableConversion getLocalVariableConversion() {
 108         return conversion;
 109     }
 110 
 111     abstract JoinPredecessor setLocalVariableConversionChanged(LexicalContext lc, LocalVariableConversion conversion);
 112 }