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;
018    
019    import org.jetbrains.annotations.NotNull;
020    import org.jetbrains.annotations.Nullable;
021    import org.jetbrains.asm4.MethodVisitor;
022    import org.jetbrains.jet.codegen.context.MethodContext;
023    import org.jetbrains.jet.codegen.signature.JvmMethodSignature;
024    import org.jetbrains.jet.codegen.state.GenerationState;
025    import org.jetbrains.jet.codegen.state.JetTypeMapper;
026    import org.jetbrains.jet.lang.descriptors.CallableDescriptor;
027    import org.jetbrains.jet.lang.psi.JetDeclarationWithBody;
028    
029    public abstract class FunctionGenerationStrategy {
030    
031        private FrameMap frameMap;
032    
033        public abstract void generateBody(
034                @NotNull MethodVisitor mv,
035                @NotNull JvmMethodSignature signature,
036                @NotNull MethodContext context,
037                @Nullable MemberCodegen parentCodegen
038        );
039    
040        @NotNull
041        protected FrameMap createFrameMap(@NotNull JetTypeMapper typeMapper, @NotNull MethodContext context) {
042            return context.prepareFrame(typeMapper);
043        }
044    
045        @NotNull
046        public FrameMap getFrameMap(@NotNull JetTypeMapper typeMapper, @NotNull MethodContext context) {
047            if (frameMap == null) {
048                frameMap = createFrameMap(typeMapper, context);
049            }
050            return frameMap;
051        }
052    
053        public boolean generateLocalVarTable() {
054            return true;
055        }
056    
057        public static class FunctionDefault extends CodegenBased<CallableDescriptor> {
058            private final JetDeclarationWithBody declaration;
059    
060            public FunctionDefault(
061                    @NotNull GenerationState state,
062                    @NotNull CallableDescriptor descriptor,
063                    @NotNull JetDeclarationWithBody declaration
064            ) {
065                super(state, descriptor);
066                this.declaration = declaration;
067            }
068    
069            @Override
070            public void doGenerateBody(@NotNull ExpressionCodegen codegen, @NotNull JvmMethodSignature signature) {
071                codegen.returnExpression(declaration.getBodyExpression());
072            }
073        }
074    
075        public abstract static class CodegenBased<T extends CallableDescriptor> extends FunctionGenerationStrategy {
076            protected final GenerationState state;
077            protected final T callableDescriptor;
078    
079            public CodegenBased(@NotNull GenerationState state, @NotNull T callableDescriptor) {
080                this.state = state;
081                this.callableDescriptor = callableDescriptor;
082            }
083    
084            @Override
085            public final void generateBody(
086                    @NotNull MethodVisitor mv,
087                    @NotNull JvmMethodSignature signature,
088                    @NotNull MethodContext context,
089                    @Nullable MemberCodegen parentCodegen
090            ) {
091                ExpressionCodegen codegen = new ExpressionCodegen(mv, getFrameMap(state.getTypeMapper(), context),
092                                                                  signature.getReturnType(), context, state, parentCodegen);
093                doGenerateBody(codegen, signature);
094            }
095    
096            public abstract void doGenerateBody(@NotNull ExpressionCodegen codegen, @NotNull JvmMethodSignature signature);
097        }
098    }