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/*
* Copyright (c) 2010, 2013, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
package jdk.nashorn.internal.ir;
import java.util.function.Function;
import jdk.nashorn.internal.codegen.types.Type;
import jdk.nashorn.internal.ir.visitor.NodeVisitor;
/**
* A wrapper for an expression that is in a position to be a join predecessor.
*/
public class JoinPredecessorExpression extends Expression implements JoinPredecessor {
private static final long serialVersionUID = 1L;
private final Expression expression;
private final LocalVariableConversion conversion;
/**
* A no-arg constructor does not wrap any expression on its own, but can be used as a place to contain a local
* variable conversion in a place where an expression can otherwise stand.
*/
public JoinPredecessorExpression() {
this(null);
}
/**
* A constructor for wrapping an expression and making it a join predecessor. Typically used on true and false
* subexpressions of the ternary node as well as on the operands of short-circuiting logical expressions {@code &&}
* and {@code ||}.
* @param expression the expression to wrap
*/
public JoinPredecessorExpression(final Expression expression) {
this(expression, null);
}
private JoinPredecessorExpression(final Expression expression, final LocalVariableConversion conversion) {
super(expression == null ? 0L : expression.getToken(), expression == null ? 0 : expression.getStart(), expression == null ? 0 : expression.getFinish());
this.expression = expression;
this.conversion = conversion;
}
@Override
public JoinPredecessor setLocalVariableConversion(final LexicalContext lc, final LocalVariableConversion conversion) {
if(conversion == this.conversion) {
return this;
}
return new JoinPredecessorExpression(expression, conversion);
}
@Override
public Type getType(final Function<Symbol, Type> localVariableTypes) {
return expression.getType(localVariableTypes);
}
@Override
public boolean isAlwaysFalse() {
return expression != null && expression.isAlwaysFalse();
}
@Override
public boolean isAlwaysTrue() {
return expression != null && expression.isAlwaysTrue();
}
/**
* Returns the underlying expression.
* @return the underlying expression.
*/
public Expression getExpression() {
return expression;
}
/**
* Sets the underlying expression.
* @param expression the new underlying expression
* @return this or modified join predecessor expression object.
*/
public JoinPredecessorExpression setExpression(final Expression expression) {
if(expression == this.expression) {
return this;
}
return new JoinPredecessorExpression(expression, conversion);
}
@Override
public LocalVariableConversion getLocalVariableConversion() {
return conversion;
}
@Override
public Node accept(final NodeVisitor<? extends LexicalContext> visitor) {
if(visitor.enterJoinPredecessorExpression(this)) {
final Expression expr = getExpression();
return visitor.leaveJoinPredecessorExpression(expr == null ? this : setExpression((Expression)expr.accept(visitor)));
}
return this;
}
@Override
public void toString(final StringBuilder sb, final boolean printType) {
if(expression != null) {
expression.toString(sb, printType);
}
if(conversion != null) {
conversion.toString(sb);
}
}
}
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