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
017package org.jetbrains.k2js.translate.expression;
018
019
020import com.google.dart.compiler.backend.js.ast.JsFunction;
021import com.google.dart.compiler.backend.js.ast.JsName;
022import com.google.dart.compiler.backend.js.ast.JsParameter;
023import com.google.dart.compiler.backend.js.ast.JsPropertyInitializer;
024import org.jetbrains.annotations.NotNull;
025import org.jetbrains.annotations.Nullable;
026import org.jetbrains.jet.lang.descriptors.DeclarationDescriptor;
027import org.jetbrains.jet.lang.descriptors.FunctionDescriptor;
028import org.jetbrains.jet.lang.descriptors.Modality;
029import org.jetbrains.jet.lang.descriptors.ValueParameterDescriptor;
030import org.jetbrains.jet.lang.psi.JetDeclarationWithBody;
031import org.jetbrains.jet.lang.psi.JetExpression;
032import org.jetbrains.jet.lang.psi.JetFunctionLiteral;
033import org.jetbrains.jet.lang.psi.JetFunctionLiteralExpression;
034import org.jetbrains.k2js.translate.context.Namer;
035import org.jetbrains.k2js.translate.context.TranslationContext;
036import org.jetbrains.k2js.translate.general.AbstractTranslator;
037import org.jetbrains.k2js.translate.utils.JsDescriptorUtils;
038import org.jetbrains.k2js.translate.utils.TranslationUtils;
039
040import java.util.ArrayList;
041import java.util.List;
042
043import static org.jetbrains.k2js.translate.utils.BindingUtils.getFunctionDescriptor;
044import static org.jetbrains.k2js.translate.utils.ErrorReportingUtils.message;
045import static org.jetbrains.k2js.translate.utils.FunctionBodyTranslator.translateFunctionBody;
046import static org.jetbrains.k2js.translate.utils.JsAstUtils.setParameters;
047import static org.jetbrains.k2js.translate.utils.JsDescriptorUtils.getExpectedReceiverDescriptor;
048
049public final class FunctionTranslator extends AbstractTranslator {
050    @NotNull
051    public static FunctionTranslator newInstance(@NotNull JetDeclarationWithBody function,
052            @NotNull TranslationContext context) {
053        return new FunctionTranslator(function, context);
054    }
055
056    @NotNull
057    private final TranslationContext functionBodyContext;
058    @NotNull
059    private final JetDeclarationWithBody functionDeclaration;
060    @Nullable
061    private JsName extensionFunctionReceiverName;
062    @NotNull
063    private final JsFunction functionObject;
064    @NotNull
065    private final FunctionDescriptor descriptor;
066
067    private FunctionTranslator(@NotNull JetDeclarationWithBody functionDeclaration,
068            @NotNull TranslationContext context) {
069        super(context);
070        this.descriptor = getFunctionDescriptor(context.bindingContext(), functionDeclaration);
071        this.functionDeclaration = functionDeclaration;
072        this.functionObject = context().getFunctionObject(descriptor);
073        assert this.functionObject.getParameters().isEmpty()
074                : message(bindingContext(), descriptor, "Function " + functionDeclaration.getText() + " processed for the second time.");
075        //NOTE: it's important we compute the context before we start the computation
076        this.functionBodyContext = getFunctionBodyContext();
077    }
078
079    @NotNull
080    private TranslationContext getFunctionBodyContext() {
081        if (isExtensionFunction()) {
082            return getFunctionBodyContextForExtensionFunction();
083        }
084        return getContextWithFunctionBodyBlock();
085    }
086
087    @NotNull
088    private TranslationContext getFunctionBodyContextForExtensionFunction() {
089        TranslationContext contextWithFunctionBodyBlock = getContextWithFunctionBodyBlock();
090        extensionFunctionReceiverName = contextWithFunctionBodyBlock.scope().declareName(Namer.getReceiverParameterName());
091        DeclarationDescriptor expectedReceiverDescriptor = getExpectedReceiverDescriptor(descriptor);
092        assert expectedReceiverDescriptor != null;
093        return contextWithFunctionBodyBlock.innerContextWithThisAliased(expectedReceiverDescriptor, extensionFunctionReceiverName);
094    }
095
096    @NotNull
097    private TranslationContext getContextWithFunctionBodyBlock() {
098        return context().newDeclaration(functionDeclaration).innerBlock(functionObject.getBody());
099    }
100
101    @NotNull
102    public JsFunction translateAsLocalFunction() {
103        JsName functionName = context().getNameForElement(functionDeclaration);
104        generateFunctionObject();
105        functionObject.setName(functionName);
106        return functionObject;
107    }
108
109    @NotNull
110    public JsPropertyInitializer translateAsEcma5PropertyDescriptor() {
111        generateFunctionObject();
112        return TranslationUtils.translateFunctionAsEcma5PropertyDescriptor(functionObject, descriptor, context());
113    }
114
115    @NotNull
116    public JsPropertyInitializer translateAsMethod() {
117        JsName functionName = context().getNameForElement(functionDeclaration);
118        generateFunctionObject();
119        return new JsPropertyInitializer(functionName.makeRef(), functionObject);
120    }
121
122    private void generateFunctionObject() {
123        setParameters(functionObject, translateParameters());
124        translateBody();
125    }
126
127    private void translateBody() {
128        JetExpression jetBodyExpression = functionDeclaration.getBodyExpression();
129        if (jetBodyExpression == null) {
130            assert descriptor.getModality().equals(Modality.ABSTRACT);
131            return;
132        }
133        functionObject.getBody().getStatements().addAll(translateFunctionBody(descriptor, functionDeclaration, functionBodyContext).getStatements());
134    }
135
136    @NotNull
137    private List<JsParameter> translateParameters() {
138        List<JsParameter> jsParameters = new ArrayList<JsParameter>();
139        mayBeAddThisParameterForExtensionFunction(jsParameters);
140        addParameters(jsParameters, descriptor, context());
141        return jsParameters;
142    }
143
144    public static void addParameters(List<JsParameter> list, FunctionDescriptor descriptor, TranslationContext context) {
145        for (ValueParameterDescriptor valueParameter : descriptor.getValueParameters()) {
146            list.add(new JsParameter(context.getNameForDescriptor(valueParameter)));
147        }
148    }
149
150    private void mayBeAddThisParameterForExtensionFunction(@NotNull List<JsParameter> jsParameters) {
151        if (isExtensionFunction()) {
152            assert extensionFunctionReceiverName != null;
153            jsParameters.add(new JsParameter(extensionFunctionReceiverName));
154        }
155    }
156
157    private boolean isExtensionFunction() {
158        return JsDescriptorUtils.isExtension(descriptor) && !(functionDeclaration instanceof JetFunctionLiteral);
159    }
160}