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 jdk.nashorn.internal.codegen.Label; 29 30 /** 31 * Common base class for jump statements (e.g. {@code break} and {@code continue}). 32 */ 33 public abstract class JumpStatement extends Statement implements JoinPredecessor { 34 private static final long serialVersionUID = 1L; 35 36 private final String labelName; 37 private final LocalVariableConversion conversion; 38 39 /** 40 * Constructor 41 * 42 * @param lineNumber line number 43 * @param token token 44 * @param finish finish 45 * @param labelName label name for break or null if none 46 */ 47 protected JumpStatement(final int lineNumber, final long token, final int finish, final String labelName) { 48 super(lineNumber, token, finish); 49 this.labelName = labelName; 50 this.conversion = null; 51 } 52 53 /** 54 * Copy constructor. 55 * @param jumpStatement the original jump statement. 56 * @param conversion a new local variable conversion. 57 */ 58 protected JumpStatement(final JumpStatement jumpStatement, final LocalVariableConversion conversion) { 59 super(jumpStatement); 60 this.labelName = jumpStatement.labelName; 61 this.conversion = conversion; 62 } 63 64 @Override 65 public boolean hasGoto() { 66 return true; 67 } 68 69 /** 70 * Get the label name for this break node 71 * @return label name, or null if none 72 */ 73 public String getLabelName() { 74 return labelName; 75 } 76 77 @Override 78 public void toString(final StringBuilder sb, final boolean printType) { 79 sb.append(getStatementName()); 80 81 if (labelName != null) { 82 sb.append(' ').append(labelName); 83 } 84 } 85 86 abstract String getStatementName(); 87 88 /** 89 * Finds the target for this jump statement in a lexical context. 90 * @param lc the lexical context 91 * @return the target, or null if not found 92 */ 93 public abstract BreakableNode getTarget(final LexicalContext lc); 94 95 /** 96 * Returns the label corresponding to this kind of jump statement (either a break or continue label) in the target. 97 * @param target the target. Note that it need not be the target of this jump statement, as the method can retrieve 98 * a label on any passed target as long as the target has a label of the requisite kind. Of course, it is advisable 99 * to invoke the method on a jump statement that targets the breakable. 100 * @return the label of the target corresponding to the kind of jump statement. 101 * @throws ClassCastException if invoked on the kind of breakable node that this jump statement is not prepared to 102 * handle. 103 */ 104 abstract Label getTargetLabel(final BreakableNode target); 105 106 /** 107 * Returns the label this jump statement targets. 108 * @param lc the lexical context 109 * @return the label this jump statement targets. 110 */ 111 public Label getTargetLabel(final LexicalContext lc) { 112 return getTargetLabel(getTarget(lc)); 113 } 114 115 /** 116 * Returns the limit node for popping scopes when this jump statement is effected. 117 * @param lc the current lexical context 118 * @return the limit node for popping scopes when this jump statement is effected. 119 */ 120 public LexicalContextNode getPopScopeLimit(final LexicalContext lc) { 121 // In most cases (break and continue) this is equal to the target. 122 return getTarget(lc); 123 } 124 125 @Override 126 public JumpStatement setLocalVariableConversion(final LexicalContext lc, final LocalVariableConversion conversion) { 127 if(this.conversion == conversion) { 128 return this; 129 } 130 return createNewJumpStatement(conversion); 131 } 132 133 abstract JumpStatement createNewJumpStatement(LocalVariableConversion newConversion); 134 135 @Override 136 public LocalVariableConversion getLocalVariableConversion() { 137 return conversion; 138 } 139 }