EquivalenceOpGen.java

/*******************************************************************************
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 ******************************************************************************/

package org.apache.sling.scripting.sightly.java.compiler.impl.operator;

import org.apache.sling.scripting.sightly.compiler.expression.SideEffectVisitor;
import org.apache.sling.scripting.sightly.java.compiler.impl.ExpressionTranslator;
import org.apache.sling.scripting.sightly.java.compiler.impl.JavaSource;
import org.apache.sling.scripting.sightly.java.compiler.impl.Type;
import org.apache.sling.scripting.sightly.compiler.expression.ExpressionNode;

/**
 * Generator for logical operators
 */
public class EquivalenceOpGen implements BinaryOpGen {

    private final boolean negated;

    public EquivalenceOpGen(boolean negated) {
        this.negated = negated;
    }

    @Override
    public Type returnType(Type left, Type right) {
        return Type.BOOLEAN;
    }

    @Override
    public void generate(JavaSource source, ExpressionTranslator visitor, TypedNode left, TypedNode right) {
        Type type = OpHelper.sameType(left, right);
        if (type != null && OpHelper.isNumericType(type) || type == Type.BOOLEAN || type == Type.UNKNOWN) {
            generateEqualsOperator(source, visitor, left.getNode(), right.getNode());
        } else if (type != Type.UNKNOWN) {
            generateEqualsMethod(source, visitor, left, right);
        }
    }

    private void generateCheckedEquals(JavaSource source, SideEffectVisitor visitor, TypedNode leftNode, TypedNode rightNode) {
        source.startExpression();
        leftNode.getNode().accept(visitor);
        source.equality().nullLiteral().conditional();
        rightNode.getNode().accept(visitor);
        source.equality().nullLiteral();
        source.conditionalBranchSep();
        generateEqualsMethod(source, visitor, leftNode, rightNode);
        source.endExpression();
    }

    private void generateEqualsMethod(JavaSource source, SideEffectVisitor visitor, TypedNode leftNode, TypedNode rightNode) {
        boolean performCast = leftNode.getType().isPrimitive();
        if (performCast) {
            source.startExpression();
            source.cast(Type.UNKNOWN.getNativeClass());
        }
        leftNode.getNode().accept(visitor);
        if (performCast) {
            source.endExpression();
        }
        source.startCall("equals", true);
        rightNode.getNode().accept(visitor);
        source.endCall();
    }

    private void generateEqualsOperator(JavaSource source, SideEffectVisitor visitor, ExpressionNode leftNode, ExpressionNode rightNode) {
        leftNode.accept(visitor);
        source.append(operator());
        rightNode.accept(visitor);
    }

    private String operator() {
        return (negated) ? "!=" : "==";
    }

}