/*
* Copyright 2015-present Facebook, Inc.
*
* 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.
*/
// 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.facebook.buck.query;
import static com.facebook.buck.query.Lexer.TokenKind;
import com.google.common.base.Preconditions;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableSet;
import com.google.common.util.concurrent.ListeningExecutorService;
import java.util.Collection;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Set;
/**
* A binary algebraic set operation.
*
* <pre>
* expr ::= expr (INTERSECT expr)+
* | expr ('^' expr)+
* | expr (UNION expr)+
* | expr ('+' expr)+
* | expr (EXCEPT expr)+
* | expr ('-' expr)+
* </pre>
*/
class BinaryOperatorExpression extends QueryExpression {
private final TokenKind operator; // ::= INTERSECT/CARET | UNION/PLUS | EXCEPT/MINUS
private final ImmutableList<QueryExpression> operands;
BinaryOperatorExpression(TokenKind operator, List<QueryExpression> operands) {
Preconditions.checkState(operands.size() > 1);
this.operator = operator;
this.operands = ImmutableList.copyOf(operands);
}
@Override
public ImmutableSet<QueryTarget> eval(QueryEnvironment env, ListeningExecutorService executor)
throws QueryException, InterruptedException {
Set<QueryTarget> lhsValue = new LinkedHashSet<>(operands.get(0).eval(env, executor));
for (int i = 1; i < operands.size(); i++) {
Set<QueryTarget> rhsValue = operands.get(i).eval(env, executor);
switch (operator) {
case INTERSECT:
case CARET:
lhsValue.retainAll(rhsValue);
break;
case UNION:
case PLUS:
lhsValue.addAll(rhsValue);
break;
case EXCEPT:
case MINUS:
lhsValue.removeAll(rhsValue);
break;
//$CASES-OMITTED$
default:
throw new IllegalStateException("operator=" + operator);
}
}
return ImmutableSet.copyOf(lhsValue);
}
@Override
public void collectTargetPatterns(Collection<String> literals) {
for (QueryExpression subExpression : operands) {
subExpression.collectTargetPatterns(literals);
}
}
@Override
public String toString() {
StringBuilder result = new StringBuilder();
for (int i = 1; i < operands.size(); i++) {
result.append("(");
}
result.append(operands.get(0));
for (int i = 1; i < operands.size(); i++) {
result.append(" " + operator.getPrettyName() + " " + operands.get(i) + ")");
}
return result.toString();
}
}