/*
* 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.common.base.MoreObjects.firstNonNull;
import com.google.auto.value.AutoValue;
import com.google.common.base.Function;
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.google.errorprone.refaster.UStatement.UnifierWithUnconsumedStatements;
import com.sun.source.tree.StatementTree;
import com.sun.source.tree.Tree;
import com.sun.source.tree.TreeVisitor;
import com.sun.source.util.TreeScanner;
import com.sun.tools.javac.tree.JCTree.JCStatement;
import com.sun.tools.javac.util.ListBuffer;
import java.util.Collection;
import java.util.List;
import java.util.UUID;
/**
* Equivalent to a no-arg block placeholder invocation.
*/
@AutoValue
abstract class UBlank implements UStatement {
static UBlank create() {
return new AutoValue_UBlank(UUID.randomUUID());
}
abstract UUID unique();
Key key() {
return new Key(unique());
}
static class Key extends Bindings.Key<List<? extends StatementTree>> {
Key(UUID k) {
super(k.toString());
}
}
private static final TreeScanner<Boolean, Unifier> FORBIDDEN_REFERENCE_SCANNER =
new TreeScanner<Boolean, Unifier>() {
@Override public Boolean reduce(Boolean l, Boolean r) {
return firstNonNull(l, false) || firstNonNull(r, false);
}
@Override public Boolean scan(Tree t, Unifier unifier) {
if (t != null) {
Boolean forbidden =
t.accept(PlaceholderUnificationVisitor.FORBIDDEN_REFERENCE_VISITOR, unifier);
return firstNonNull(forbidden, false) || firstNonNull(super.scan(t, unifier), false);
}
return false;
}
};
@Override
public Tree.Kind getKind() {
return Kind.OTHER;
}
@Override
public <R, D> R accept(TreeVisitor<R, D> visitor, D data) {
return visitor.visitOther(this, data);
}
@Override
public Choice<UnifierWithUnconsumedStatements> apply(
final UnifierWithUnconsumedStatements state) {
int goodIndex = 0;
while (goodIndex < state.unconsumedStatements().size()) {
StatementTree stmt = state.unconsumedStatements().get(goodIndex);
if (firstNonNull(FORBIDDEN_REFERENCE_SCANNER.scan(stmt, state.unifier()), false)
&& ControlFlowVisitor.INSTANCE.visitStatement(stmt)
== ControlFlowVisitor.Result.NEVER_EXITS) {
break;
} else {
goodIndex++;
}
}
Collection<Integer> breakPoints =
ContiguousSet.create(Range.closed(0, goodIndex), DiscreteDomain.integers());
return Choice.from(breakPoints).transform(
new Function<Integer, UnifierWithUnconsumedStatements>() {
@Override public UnifierWithUnconsumedStatements apply(Integer k) {
Unifier unifier = state.unifier().fork();
unifier.putBinding(key(), state.unconsumedStatements().subList(0, k));
List<? extends StatementTree> remaining = state.unconsumedStatements()
.subList(k, state.unconsumedStatements().size());
return UnifierWithUnconsumedStatements.create(unifier, remaining);
}
});
}
@Override public com.sun.tools.javac.util.List<JCStatement> inlineStatements(Inliner inliner) {
ListBuffer<JCStatement> buffer = new ListBuffer<>();
for (StatementTree stmt :
inliner.getOptionalBinding(key()).or(ImmutableList.<StatementTree>of())) {
buffer.add((JCStatement) stmt);
}
return buffer.toList();
}
}