/*
* 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.collect.Iterables;
import com.google.errorprone.util.ASTHelpers;
import com.sun.source.tree.IdentifierTree;
import com.sun.source.tree.Tree;
import com.sun.source.util.TreeScanner;
import com.sun.tools.javac.code.Symbol;
import com.sun.tools.javac.tree.JCTree.JCExpression;
import com.sun.tools.javac.util.Names;
import javax.annotation.Nullable;
/**
* Free identifier that can be bound to any expression of the appropriate type.
*
* @author lowasser@google.com (Louis Wasserman)
*/
@AutoValue
public abstract class UFreeIdent extends UIdent {
static class Key extends Bindings.Key<JCExpression> {
Key(CharSequence name) {
super(name.toString());
}
}
public static UFreeIdent create(CharSequence identifier) {
return new AutoValue_UFreeIdent(StringName.of(identifier));
}
@Override
public abstract StringName getName();
public Key key() {
return new Key(getName());
}
@Override
public JCExpression inline(Inliner inliner) {
return inliner.getBinding(key());
}
private static boolean trueOrNull(@Nullable Boolean condition) {
return condition == null || condition;
}
@Override
public Choice<Unifier> visitIdentifier(IdentifierTree node, Unifier unifier) {
Names names = Names.instance(unifier.getContext());
return node.getName().equals(names._super)
? Choice.<Unifier>none()
: defaultAction(node, unifier);
}
@Override
protected Choice<Unifier> defaultAction(Tree target, final Unifier unifier) {
if (target instanceof JCExpression) {
JCExpression expression = (JCExpression) target;
JCExpression currentBinding = unifier.getBinding(key());
// Check that the expression does not reference any template-local variables.
boolean isGood = trueOrNull(new TreeScanner<Boolean, Void>() {
@Override
public Boolean reduce(@Nullable Boolean left, @Nullable Boolean right) {
return trueOrNull(left) && trueOrNull(right);
}
@Override
public Boolean visitIdentifier(IdentifierTree ident, Void v) {
Symbol identSym = ASTHelpers.getSymbol(ident);
for (ULocalVarIdent.Key key :
Iterables.filter(unifier.getBindings().keySet(), ULocalVarIdent.Key.class)) {
if (identSym == unifier.getBinding(key).getSymbol()) {
return false;
}
}
return true;
}
}.scan(expression, null));
if (!isGood) {
return Choice.none();
} else if (currentBinding == null) {
unifier.putBinding(key(), expression);
return Choice.of(unifier);
} else if (currentBinding.toString().equals(expression.toString())) {
// TODO(lowasser): try checking types here in a way that doesn't reject
// different wildcard captures
// If it's the same code, treat it as the same expression.
return Choice.of(unifier);
}
}
return Choice.none();
}
}