com.google.errorprone.refaster.UBlank Maven / Gradle / Ivy
/*
* Copyright 2014 The Error Prone Authors.
*
* 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.collect.ContiguousSet;
import com.google.common.collect.DiscreteDomain;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableSortedSet;
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.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> {
Key(UUID k) {
super(k.toString());
}
}
private static final TreeScanner FORBIDDEN_REFERENCE_SCANNER =
new TreeScanner() {
@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 accept(TreeVisitor visitor, D data) {
return visitor.visitOther(this, data);
}
@Override
public Choice apply(UnifierWithUnconsumedStatements state) {
int goodIndex = 0;
while (goodIndex < state.unconsumedStatements().size()) {
StatementTree stmt = state.unconsumedStatements().get(goodIndex);
// If the statement refers to bound variables or might exit, stop consuming statements.
if (firstNonNull(FORBIDDEN_REFERENCE_SCANNER.scan(stmt, state.unifier()), false)
|| ControlFlowVisitor.INSTANCE.visitStatement(stmt)
!= ControlFlowVisitor.Result.NEVER_EXITS) {
break;
} else {
goodIndex++;
}
}
ImmutableSortedSet breakPoints =
ContiguousSet.create(Range.closed(0, goodIndex), DiscreteDomain.integers());
return Choice.from(breakPoints)
.transform(
(Integer k) -> {
Unifier unifier = state.unifier().fork();
unifier.putBinding(key(), state.unconsumedStatements().subList(0, k));
ImmutableList remaining =
state.unconsumedStatements().subList(k, state.unconsumedStatements().size());
return UnifierWithUnconsumedStatements.create(unifier, remaining);
});
}
@Override
public com.sun.tools.javac.util.List inlineStatements(Inliner inliner) {
ListBuffer buffer = new ListBuffer<>();
for (StatementTree stmt :
inliner.getOptionalBinding(key()).or(ImmutableList.of())) {
buffer.add((JCStatement) stmt);
}
return buffer.toList();
}
}