001    /*
002     * Copyright 2010-2013 JetBrains s.r.o.
003     *
004     * Licensed under the Apache License, Version 2.0 (the "License");
005     * you may not use this file except in compliance with the License.
006     * You may obtain a copy of the License at
007     *
008     * http://www.apache.org/licenses/LICENSE-2.0
009     *
010     * Unless required by applicable law or agreed to in writing, software
011     * distributed under the License is distributed on an "AS IS" BASIS,
012     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013     * See the License for the specific language governing permissions and
014     * limitations under the License.
015     */
016    
017    package org.jetbrains.k2js.translate.intrinsic.operation;
018    
019    import com.google.dart.compiler.backend.js.ast.JsBinaryOperation;
020    import com.google.dart.compiler.backend.js.ast.JsBinaryOperator;
021    import com.google.dart.compiler.backend.js.ast.JsExpression;
022    import com.google.dart.compiler.backend.js.ast.JsLiteral;
023    import org.jetbrains.annotations.NotNull;
024    import org.jetbrains.jet.lang.descriptors.FunctionDescriptor;
025    import org.jetbrains.jet.lang.psi.JetBinaryExpression;
026    import org.jetbrains.jet.lang.psi.JetExpression;
027    import org.jetbrains.jet.lang.resolve.name.Name;
028    import org.jetbrains.jet.lang.types.expressions.OperatorConventions;
029    import org.jetbrains.jet.lexer.JetTokens;
030    import org.jetbrains.k2js.translate.context.TranslationContext;
031    import org.jetbrains.k2js.translate.intrinsic.functions.factories.TopLevelFIF;
032    import org.jetbrains.k2js.translate.intrinsic.functions.patterns.NamePredicate;
033    import org.jetbrains.k2js.translate.utils.JsAstUtils;
034    import org.jetbrains.k2js.translate.utils.JsDescriptorUtils;
035    import org.jetbrains.k2js.translate.utils.TranslationUtils;
036    
037    import java.util.Arrays;
038    
039    import static org.jetbrains.k2js.translate.utils.BindingUtils.getFunctionDescriptorForOperationExpression;
040    import static org.jetbrains.k2js.translate.utils.PsiUtils.getOperationToken;
041    
042    public final class EqualsIntrinsic implements BinaryOperationIntrinsic {
043    
044        @Override
045        public boolean isApplicable(@NotNull JetBinaryExpression expression, @NotNull TranslationContext context) {
046            if (!OperatorConventions.EQUALS_OPERATIONS.contains(getOperationToken(expression))) {
047                return false;
048            }
049            FunctionDescriptor functionDescriptor = getFunctionDescriptorForOperationExpression(context.bindingContext(), expression);
050            assert functionDescriptor != null;
051            return JsDescriptorUtils.isStandardDeclaration(functionDescriptor);
052        }
053    
054        @Override
055        @NotNull
056        public JsExpression apply(@NotNull JetBinaryExpression expression,
057                @NotNull JsExpression left,
058                @NotNull JsExpression right,
059                @NotNull TranslationContext context) {
060            boolean isNegated = getOperationToken(expression).equals(JetTokens.EXCLEQ);
061            if (right == JsLiteral.NULL || left == JsLiteral.NULL) {
062                return TranslationUtils.nullCheck(right == JsLiteral.NULL ? left : right, isNegated);
063            }
064            else if (canUseSimpleEquals(expression, context)) {
065                return new JsBinaryOperation(isNegated ? JsBinaryOperator.REF_NEQ : JsBinaryOperator.REF_EQ, left, right);
066            }
067    
068            JsExpression result = TopLevelFIF.EQUALS.apply(left, Arrays.asList(right), context);
069            return isNegated ? JsAstUtils.negated(result) : result;
070        }
071    
072        private static boolean canUseSimpleEquals(@NotNull JetBinaryExpression expression, @NotNull TranslationContext context) {
073            JetExpression left = expression.getLeft();
074            assert left != null : "No left-hand side: " + expression.getText();
075            Name typeName = JsDescriptorUtils.getNameIfStandardType(left, context);
076            return typeName != null && NamePredicate.PRIMITIVE_NUMBERS.apply(typeName);
077        }
078    }