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.jet.codegen.intrinsics;
018    
019    import com.intellij.psi.PsiElement;
020    import org.jetbrains.annotations.NotNull;
021    import org.jetbrains.asm4.Type;
022    import org.jetbrains.asm4.commons.InstructionAdapter;
023    import org.jetbrains.jet.codegen.ExpressionCodegen;
024    import org.jetbrains.jet.codegen.StackValue;
025    import org.jetbrains.jet.codegen.state.GenerationState;
026    import org.jetbrains.jet.lang.psi.JetExpression;
027    import org.jetbrains.jet.lang.resolve.java.AsmTypeConstants;
028    
029    import java.util.List;
030    
031    import static org.jetbrains.jet.codegen.AsmUtil.genInvokeAppendMethod;
032    import static org.jetbrains.jet.codegen.AsmUtil.genStringBuilderConstructor;
033    
034    public class Concat implements IntrinsicMethod {
035        @Override
036        public StackValue generate(
037                ExpressionCodegen codegen,
038                InstructionAdapter v,
039                @NotNull Type expectedType,
040                PsiElement element,
041                List<JetExpression> arguments,
042                StackValue receiver,
043                @NotNull GenerationState state
044        ) {
045            if (receiver == null || receiver == StackValue.none()) {                                                     // LHS + RHS
046                genStringBuilderConstructor(v);
047                codegen.invokeAppend(arguments.get(0));                                // StringBuilder(LHS)
048                codegen.invokeAppend(arguments.get(1));
049            }
050            else {                                    // LHS.plus(RHS)
051                receiver.put(AsmTypeConstants.OBJECT_TYPE, v);
052                genStringBuilderConstructor(v);
053                v.swap();                                                              // StringBuilder LHS
054                genInvokeAppendMethod(v, expectedType);  // StringBuilder(LHS)
055                codegen.invokeAppend(arguments.get(0));
056            }
057    
058            v.invokevirtual("java/lang/StringBuilder", "toString", "()Ljava/lang/String;");
059            StackValue.onStack(AsmTypeConstants.JAVA_STRING_TYPE).put(expectedType, v);
060            return StackValue.onStack(expectedType);
061        }
062    }