/*
* Copyright 2014 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 static com.google.errorprone.refaster.Unifier.unifications;
import static com.google.errorprone.refaster.Unifier.unifyList;
import com.google.auto.value.AutoValue;
import com.google.common.base.Optional;
import com.google.common.collect.ImmutableList;
import com.sun.source.tree.LambdaExpressionTree;
import com.sun.source.tree.TreeVisitor;
import com.sun.tools.javac.tree.JCTree;
import com.sun.tools.javac.tree.JCTree.JCExpressionStatement;
import com.sun.tools.javac.tree.JCTree.JCLambda;
import com.sun.tools.javac.tree.JCTree.JCLambda.ParameterKind;
import com.sun.tools.javac.tree.JCTree.JCReturn;
import com.sun.tools.javac.tree.JCTree.JCStatement;
import com.sun.tools.javac.tree.JCTree.JCVariableDecl;
import com.sun.tools.javac.util.List;
import com.sun.tools.javac.util.ListBuffer;
/**
* {@code UTree} representation of a {@code LambdaExpressionTree}.
*
* @author lowasser@google.com (Louis Wasserman)
*/
@AutoValue
abstract class ULambda extends UExpression implements LambdaExpressionTree {
public static ULambda create(
ParameterKind parameterKind, Iterable<UVariableDecl> parameters, UTree<?> body) {
return new AutoValue_ULambda(parameterKind, ImmutableList.copyOf(parameters), body);
}
@Override
public Kind getKind() {
return Kind.LAMBDA_EXPRESSION;
}
@Override
public <R, D> R accept(TreeVisitor<R, D> visitor, D data) {
return visitor.visitLambdaExpression(this, data);
}
@Override
public Choice<Unifier> visitLambdaExpression(LambdaExpressionTree node, Unifier unifier) {
return unifyList(unifier, getParameters(), node.getParameters())
.thenChoose(unifications(getBody(), node.getBody()));
}
@Override
public JCLambda inline(Inliner inliner) throws CouldNotResolveImportException {
return inliner.maker().Lambda(inlineParams(inliner), inlineBody(inliner));
}
public List<JCVariableDecl> inlineParams(Inliner inliner) throws CouldNotResolveImportException {
if (parameterKind() == ParameterKind.EXPLICIT) {
return List.convert(JCVariableDecl.class, inliner.inlineList(getParameters()));
}
ListBuffer<JCVariableDecl> params = new ListBuffer<>();
for (UVariableDecl param : getParameters()) {
params.add(param.inlineImplicitType(inliner));
}
return params.toList();
}
JCTree inlineBody(Inliner inliner) throws CouldNotResolveImportException {
if (getBody() instanceof UPlaceholderExpression) {
UPlaceholderExpression body = (UPlaceholderExpression) getBody();
Optional<List<JCStatement>> blockBinding =
inliner.getOptionalBinding(body.placeholder().blockKey());
if (blockBinding.isPresent()) {
// this lambda is of the form args -> blockPlaceholder();
List<JCStatement> blockInlined =
UPlaceholderExpression.copier(body.arguments(), inliner)
.copy(blockBinding.get(), inliner);
if (blockInlined.size() == 1) {
if (blockInlined.get(0) instanceof JCReturn) {
return ((JCReturn) blockInlined.get(0)).getExpression();
} else if (blockInlined.get(0) instanceof JCExpressionStatement) {
return ((JCExpressionStatement) blockInlined.get(0)).getExpression();
}
}
return inliner.maker().Block(0, blockInlined);
}
}
return getBody().inline(inliner);
}
abstract ParameterKind parameterKind();
@Override
public abstract ImmutableList<UVariableDecl> getParameters();
@Override
public abstract UTree<?> getBody();
@Override
public BodyKind getBodyKind() {
return getBody().getKind() == Kind.BLOCK ? BodyKind.STATEMENT : BodyKind.EXPRESSION;
}
}