CaseNode.java revision 1068:34ef988d5959 
1/*
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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
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23 * questions.
24 */
25
26package jdk.nashorn.internal.ir;
27
28import java.util.Collections;
29import java.util.List;
30import jdk.nashorn.internal.codegen.Label;
31import jdk.nashorn.internal.ir.annotations.Immutable;
32import jdk.nashorn.internal.ir.visitor.NodeVisitor;
33
34/**
35 * IR representation of CASE clause.
36 * Case nodes are not BreakableNodes, but the SwitchNode is
37 */
38@Immutable
39public final class CaseNode extends Node implements JoinPredecessor, Labels, Terminal {
40    private static final long serialVersionUID = 1L;
41
42    /** Test expression. */
43    private final Expression test;
44
45    /** Statements. */
46    private final Block body;
47
48    /** Case entry label. */
49    private final Label entry;
50
51    /**
52     * @see JoinPredecessor
53     */
54    private final LocalVariableConversion conversion;
55
56    /**
57     * Constructors
58     *
59     * @param token    token
60     * @param finish   finish
61     * @param test     case test node, can be any node in JavaScript
62     * @param body     case body
63     */
64    public CaseNode(final long token, final int finish, final Expression test, final Block body) {
65        super(token, finish);
66
67        this.test  = test;
68        this.body  = body;
69        this.entry = new Label("entry");
70        this.conversion = null;
71    }
72
73    CaseNode(final CaseNode caseNode, final Expression test, final Block body, final LocalVariableConversion conversion) {
74        super(caseNode);
75
76        this.test  = test;
77        this.body  = body;
78        this.entry = new Label(caseNode.entry);
79        this.conversion = conversion;
80    }
81
82    /**
83     * Is this a terminal case node, i.e. does it end control flow like having a throw or return?
84     *
85     * @return true if this node statement is terminal
86     */
87    @Override
88    public boolean isTerminal() {
89        return body.isTerminal();
90    }
91
92    /**
93     * Assist in IR navigation.
94     * @param visitor IR navigating visitor.
95     */
96    @Override
97    public Node accept(final NodeVisitor<? extends LexicalContext> visitor) {
98        if (visitor.enterCaseNode(this)) {
99            final Expression newTest = test == null ? null : (Expression)test.accept(visitor);
100            final Block newBody = body == null ? null : (Block)body.accept(visitor);
101
102            return visitor.leaveCaseNode(setTest(newTest).setBody(newBody));
103        }
104
105        return this;
106    }
107
108    @Override
109    public void toString(final StringBuilder sb, final boolean printTypes) {
110        if (test != null) {
111            sb.append("case ");
112            test.toString(sb, printTypes);
113            sb.append(':');
114        } else {
115            sb.append("default:");
116        }
117    }
118
119    /**
120     * Get the body for this case node
121     * @return the body
122     */
123    public Block getBody() {
124        return body;
125    }
126
127    /**
128     * Get the entry label for this case node
129     * @return the entry label
130     */
131    public Label getEntry() {
132        return entry;
133    }
134
135    /**
136     * Get the test expression for this case node
137     * @return the test
138     */
139    public Expression getTest() {
140        return test;
141    }
142
143    /**
144     * Reset the test expression for this case node
145     * @param test new test expression
146     * @return new or same CaseNode
147     */
148    public CaseNode setTest(final Expression test) {
149        if (this.test == test) {
150            return this;
151        }
152        return new CaseNode(this, test, body, conversion);
153    }
154
155    @Override
156    public JoinPredecessor setLocalVariableConversion(final LexicalContext lc, final LocalVariableConversion conversion) {
157        if(this.conversion == conversion) {
158            return this;
159        }
160        return new CaseNode(this, test, body, conversion);
161    }
162
163    @Override
164    public LocalVariableConversion getLocalVariableConversion() {
165        return conversion;
166    }
167
168    private CaseNode setBody(final Block body) {
169        if (this.body == body) {
170            return this;
171        }
172        return new CaseNode(this, test, body, conversion);
173    }
174
175    @Override
176    public List<Label> getLabels() {
177        return Collections.unmodifiableList(Collections.singletonList(entry));
178    }
179}
180