/*
* 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.presto.sql.analyzer;
import com.facebook.presto.sql.tree.Expression;
import com.facebook.presto.sql.tree.Node;
import com.facebook.presto.sql.util.AstUtils;
import java.util.Map;
import java.util.Objects;
import java.util.stream.Stream;
import static java.util.Objects.requireNonNull;
/**
* Extract expressions that are references to a given scope.
*/
class ScopeReferenceExtractor
{
private ScopeReferenceExtractor() {}
public static boolean hasReferencesToScope(Node node, Analysis analysis, Scope scope)
{
return getReferencesToScope(node, analysis, scope).findAny().isPresent();
}
public static Stream<Expression> getReferencesToScope(Node node, Analysis analysis, Scope scope)
{
Map<Expression, FieldId> columnReferences = analysis.getColumnReferenceFields();
return AstUtils.preOrder(node)
.filter(columnReferences::containsKey)
.map(Expression.class::cast)
.filter(expression -> isReferenceToScope(expression, scope, columnReferences));
}
private static boolean isReferenceToScope(Expression node, Scope scope, Map<Expression, FieldId> columnReferences)
{
FieldId fieldId = columnReferences.get(node);
requireNonNull(fieldId, () -> "No FieldId for " + node);
return isFieldFromScope(fieldId, scope);
}
public static boolean isFieldFromScope(FieldId fieldId, Scope scope)
{
return Objects.equals(fieldId.getRelationId(), scope.getRelationId());
}
}