com.google.errorprone.refaster.UClassDecl.java Source code

Introduction

Here is the source code for com.google.errorprone.refaster.UClassDecl.java

Source

/*
 * Copyright 2013 Google Inc. All rights reserved.
 *
 * Licensed 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 com.google.errorprone.refaster;

import com.google.auto.value.AutoValue;
import com.google.common.base.Function;
import com.google.common.base.Optional;
import com.google.common.collect.ContiguousSet;
import com.google.common.collect.DiscreteDomain;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.Range;
import com.sun.source.tree.ClassTree;
import com.sun.source.tree.MethodTree;
import com.sun.source.tree.ModifiersTree;
import com.sun.source.tree.Tree;
import com.sun.source.tree.TreeVisitor;
import com.sun.source.tree.TypeParameterTree;
import com.sun.tools.javac.tree.JCTree;
import com.sun.tools.javac.tree.JCTree.JCClassDecl;
import com.sun.tools.javac.util.List;
import javax.lang.model.element.Name;

/**
 * {@code UTree} representation of a {@code ClassTree} for anonymous inner class matching.
 * 
 * @author lowasser@google.com (Louis Wasserman)
 */
@AutoValue
abstract class UClassDecl extends USimpleStatement implements ClassTree {
    public static UClassDecl create(UMethodDecl... members) {
        return create(ImmutableList.copyOf(members));
    }

    public static UClassDecl create(Iterable<UMethodDecl> members) {
        return new AutoValue_UClassDecl(ImmutableList.copyOf(members));
    }

    @AutoValue
    abstract static class UnifierWithRemainingMembers {
        static UnifierWithRemainingMembers create(Unifier unifier, Iterable<UMethodDecl> remainingMembers) {
            return new AutoValue_UClassDecl_UnifierWithRemainingMembers(unifier,
                    ImmutableList.copyOf(remainingMembers));
        }

        abstract Unifier unifier();

        abstract ImmutableList<UMethodDecl> remainingMembers();

        static final Function<Unifier, UnifierWithRemainingMembers> withRemaining(
                final Iterable<UMethodDecl> remainingMembers) {
            return new Function<Unifier, UnifierWithRemainingMembers>() {
                @Override
                public UnifierWithRemainingMembers apply(Unifier unifier) {
                    return create(unifier, remainingMembers);
                }
            };
        }
    }

    private static Function<UnifierWithRemainingMembers, Choice<UnifierWithRemainingMembers>> match(
            final Tree tree) {
        return new Function<UnifierWithRemainingMembers, Choice<UnifierWithRemainingMembers>>() {
            @Override
            public Choice<UnifierWithRemainingMembers> apply(final UnifierWithRemainingMembers state) {
                final ImmutableList<UMethodDecl> currentMembers = state.remainingMembers();
                Choice<Integer> methodChoice = Choice.from(ContiguousSet
                        .create(Range.closedOpen(0, currentMembers.size()), DiscreteDomain.integers()));
                return methodChoice.thenChoose(new Function<Integer, Choice<UnifierWithRemainingMembers>>() {
                    @Override
                    public Choice<UnifierWithRemainingMembers> apply(Integer i) {
                        ImmutableList<UMethodDecl> remainingMembers = new ImmutableList.Builder<UMethodDecl>()
                                .addAll(currentMembers.subList(0, i))
                                .addAll(currentMembers.subList(i + 1, currentMembers.size())).build();
                        UMethodDecl chosenMethod = currentMembers.get(i);
                        Unifier unifier = state.unifier().fork();
                        /* 
                         * If multiple methods use the same parameter name, preserve the last parameter
                         * name from the target code.  For example, given a @BeforeTemplate with
                         * 
                         *    int get(int index) {...}
                         *    int set(int index, int value) {...}
                         *    
                         * and target code with the lines
                         * 
                         *    int get(int i) {...}
                         *    int set(int j) {...}
                         *    
                         * then use "j" in place of index in the @AfterTemplates.
                         */
                        for (UVariableDecl param : chosenMethod.getParameters()) {
                            unifier.clearBinding(param.key());
                        }
                        return chosenMethod.unify(tree, unifier)
                                .transform(UnifierWithRemainingMembers.withRemaining(remainingMembers));
                    }
                });
            }
        };
    }

    @Override
    public Choice<Unifier> visitClass(ClassTree node, Unifier unifier) {
        Choice<UnifierWithRemainingMembers> path = Choice
                .of(UnifierWithRemainingMembers.create(unifier, getMembers()));
        for (Tree targetMember : node.getMembers()) {
            if (!(targetMember instanceof MethodTree) || ((MethodTree) targetMember).getReturnType() != null) {
                // skip synthetic constructors
                path = path.thenChoose(match(targetMember));
            }
        }
        return path.thenOption(new Function<UnifierWithRemainingMembers, Optional<Unifier>>() {
            @Override
            public Optional<Unifier> apply(UnifierWithRemainingMembers state) {
                if (state.remainingMembers().isEmpty()) {
                    return Optional.of(state.unifier());
                } else {
                    return Optional.absent();
                }
            }
        });
    }

    @Override
    public JCClassDecl inline(Inliner inliner) throws CouldNotResolveImportException {
        return inliner.maker().AnonymousClassDef(inliner.maker().Modifiers(0L),
                List.convert(JCTree.class, inliner.inlineList(getMembers())));
    }

    @Override
    public <R, D> R accept(TreeVisitor<R, D> visitor, D data) {
        return visitor.visitClass(this, data);
    }

    @Override
    public Kind getKind() {
        return Kind.CLASS;
    }

    @Override
    public UTree<?> getExtendsClause() {
        return null;
    }

    @Override
    public ImmutableList<UTree<?>> getImplementsClause() {
        return ImmutableList.of();
    }

    @Override
    public abstract ImmutableList<UMethodDecl> getMembers();

    @Override
    public ModifiersTree getModifiers() {
        return null;
    }

    @Override
    public Name getSimpleName() {
        return null;
    }

    @Override
    public ImmutableList<TypeParameterTree> getTypeParameters() {
        return ImmutableList.of();
    }

}