IfNode.java revision 953:221a84ef44c0 
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
26package jdk.nashorn.internal.ir;
27
28import jdk.nashorn.internal.ir.annotations.Immutable;
29import jdk.nashorn.internal.ir.visitor.NodeVisitor;
30
31/**
32 * IR representation for an IF statement.
33 */
34@Immutable
35public final class IfNode extends Statement implements JoinPredecessor {
36    /** Test expression. */
37    private final Expression test;
38
39    /** Pass statements. */
40    private final Block pass;
41
42    /** Fail statements. */
43    private final Block fail;
44
45    /**
46     * Local variable conversions that need to be performed after test if it evaluates to false, and there's no else
47     * branch.
48     */
49    private final LocalVariableConversion conversion;
50
51    /**
52     * Constructor
53     *
54     * @param lineNumber line number
55     * @param token      token
56     * @param finish     finish
57     * @param test       test
58     * @param pass       block to execute when test passes
59     * @param fail       block to execute when test fails or null
60     */
61    public IfNode(final int lineNumber, final long token, final int finish, final Expression test, final Block pass, final Block fail) {
62        super(lineNumber, token, finish);
63        this.test = test;
64        this.pass = pass;
65        this.fail = fail;
66        this.conversion = null;
67    }
68
69    private IfNode(final IfNode ifNode, final Expression test, final Block pass, final Block fail, final LocalVariableConversion conversion) {
70        super(ifNode);
71        this.test = test;
72        this.pass = pass;
73        this.fail = fail;
74        this.conversion = conversion;
75    }
76
77    @Override
78    public boolean isTerminal() {
79        return pass.isTerminal() && fail != null && fail.isTerminal();
80    }
81
82    @Override
83    public Node accept(final NodeVisitor<? extends LexicalContext> visitor) {
84        if (visitor.enterIfNode(this)) {
85            return visitor.leaveIfNode(
86                setTest((Expression)test.accept(visitor)).
87                setPass((Block)pass.accept(visitor)).
88                setFail(fail == null ? null : (Block)fail.accept(visitor)));
89        }
90
91        return this;
92    }
93
94    @Override
95    public void toString(final StringBuilder sb, final boolean printTypes) {
96        sb.append("if (");
97        test.toString(sb, printTypes);
98        sb.append(')');
99    }
100
101    /**
102     * Get the else block of this IfNode
103     * @return the else block, or null if none exists
104     */
105    public Block getFail() {
106        return fail;
107    }
108
109    private IfNode setFail(final Block fail) {
110        if (this.fail == fail) {
111            return this;
112        }
113        return new IfNode(this, test, pass, fail, conversion);
114    }
115
116    /**
117     * Get the then block for this IfNode
118     * @return the then block
119     */
120    public Block getPass() {
121        return pass;
122    }
123
124    private IfNode setPass(final Block pass) {
125        if (this.pass == pass) {
126            return this;
127        }
128        return new IfNode(this, test, pass, fail, conversion);
129    }
130
131    /**
132     * Get the test expression for this IfNode
133     * @return the test expression
134     */
135    public Expression getTest() {
136        return test;
137    }
138
139    /**
140     * Reset the test expression for this IfNode
141     * @param test a new test expression
142     * @return new or same IfNode
143     */
144    public IfNode setTest(final Expression test) {
145        if (this.test == test) {
146            return this;
147        }
148        return new IfNode(this, test, pass, fail, conversion);
149    }
150
151    @Override
152    public IfNode setLocalVariableConversion(final LexicalContext lc, final LocalVariableConversion conversion) {
153        if(this.conversion == conversion) {
154            return this;
155        }
156        return new IfNode(this, test, pass, fail, conversion);
157    }
158
159    @Override
160    public LocalVariableConversion getLocalVariableConversion() {
161        return conversion;
162    }
163}
164