/*
* 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.DereferenceExpression;
import com.facebook.presto.sql.tree.Expression;
import com.facebook.presto.sql.tree.Identifier;
import com.facebook.presto.sql.tree.QualifiedName;
import com.facebook.presto.sql.tree.WithQuery;
import com.google.common.collect.ImmutableMap;
import javax.annotation.concurrent.Immutable;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Optional;
import static com.facebook.presto.sql.analyzer.SemanticExceptions.ambiguousAttributeException;
import static com.facebook.presto.sql.analyzer.SemanticExceptions.missingAttributeException;
import static com.google.common.base.MoreObjects.toStringHelper;
import static com.google.common.base.Preconditions.checkArgument;
import static com.google.common.collect.Iterables.getOnlyElement;
import static java.util.Objects.requireNonNull;
@Immutable
public class Scope
{
private final Optional<Scope> parent;
private final boolean queryBoundary;
private final RelationId relationId;
private final RelationType relation;
private final Map<String, WithQuery> namedQueries;
public static Scope create()
{
return builder().build();
}
public static Builder builder()
{
return new Builder();
}
private Scope(
Optional<Scope> parent,
boolean queryBoundary,
RelationId relationId,
RelationType relation,
Map<String, WithQuery> namedQueries)
{
this.parent = requireNonNull(parent, "parent is null");
this.relationId = requireNonNull(relationId, "relationId is null");
this.queryBoundary = queryBoundary;
this.relation = requireNonNull(relation, "relation is null");
this.namedQueries = ImmutableMap.copyOf(requireNonNull(namedQueries, "namedQueries is null"));
}
public Optional<Scope> getOuterQueryParent()
{
Scope scope = this;
while (scope.parent.isPresent()) {
if (scope.queryBoundary) {
return scope.parent;
}
scope = scope.parent.get();
}
return Optional.empty();
}
public Optional<Scope> getLocalParent()
{
if (!queryBoundary) {
return parent;
}
return Optional.empty();
}
public RelationId getRelationId()
{
return relationId;
}
public RelationType getRelationType()
{
return relation;
}
public ResolvedField resolveField(Expression expression, QualifiedName name)
{
return tryResolveField(expression, name).orElseThrow(() -> missingAttributeException(expression, name));
}
public Optional<ResolvedField> tryResolveField(Expression expression)
{
QualifiedName qualifiedName = asQualifiedName(expression);
if (qualifiedName != null) {
return tryResolveField(expression, qualifiedName);
}
return Optional.empty();
}
private static QualifiedName asQualifiedName(Expression expression)
{
QualifiedName name = null;
if (expression instanceof Identifier) {
name = QualifiedName.of(((Identifier) expression).getName());
}
else if (expression instanceof DereferenceExpression) {
name = DereferenceExpression.getQualifiedName((DereferenceExpression) expression);
}
return name;
}
public Optional<ResolvedField> tryResolveField(Expression node, QualifiedName name)
{
return resolveField(node, name, 0, true);
}
private Optional<ResolvedField> resolveField(Expression node, QualifiedName name, int fieldIndexOffset, boolean local)
{
List<Field> matches = relation.resolveFields(name);
if (matches.size() > 1) {
throw ambiguousAttributeException(node, name);
}
else if (matches.size() == 1) {
return Optional.of(asResolvedField(getOnlyElement(matches), fieldIndexOffset, local));
}
else {
if (isColumnReference(name, relation)) {
return Optional.empty();
}
if (parent.isPresent()) {
return parent.get().resolveField(node, name, fieldIndexOffset + relation.getAllFieldCount(), local && !queryBoundary);
}
return Optional.empty();
}
}
private ResolvedField asResolvedField(Field field, int fieldIndexOffset, boolean local)
{
int relationFieldIndex = relation.indexOf(field);
int hierarchyFieldIndex = relation.indexOf(field) + fieldIndexOffset;
return new ResolvedField(this, field, hierarchyFieldIndex, relationFieldIndex, local);
}
public boolean isColumnReference(QualifiedName name)
{
Scope current = this;
while (current != null) {
if (isColumnReference(name, current.relation)) {
return true;
}
current = current.parent.orElse(null);
}
return false;
}
private static boolean isColumnReference(QualifiedName name, RelationType relation)
{
while (name.getPrefix().isPresent()) {
name = name.getPrefix().get();
if (!relation.resolveFields(name).isEmpty()) {
return true;
}
}
return false;
}
public Optional<WithQuery> getNamedQuery(String name)
{
if (namedQueries.containsKey(name)) {
return Optional.of(namedQueries.get(name));
}
if (parent.isPresent()) {
return parent.get().getNamedQuery(name);
}
return Optional.empty();
}
@Override
public String toString()
{
return toStringHelper(this)
.addValue(relationId)
.toString();
}
public static final class Builder
{
private RelationId relationId = RelationId.anonymous();
private RelationType relationType = new RelationType();
private final Map<String, WithQuery> namedQueries = new HashMap<>();
private Optional<Scope> parent = Optional.empty();
private boolean queryBoundary;
public Builder withRelationType(RelationId relationId, RelationType relationType)
{
this.relationId = requireNonNull(relationId, "relationId is null");
this.relationType = requireNonNull(relationType, "relationType is null");
return this;
}
public Builder withParent(Scope parent)
{
checkArgument(!this.parent.isPresent(), "parent is already set");
this.parent = Optional.of(parent);
return this;
}
public Builder withOuterQueryParent(Scope parent)
{
checkArgument(!this.parent.isPresent(), "parent is already set");
this.parent = Optional.of(parent);
this.queryBoundary = true;
return this;
}
public Builder withNamedQuery(String name, WithQuery withQuery)
{
checkArgument(!containsNamedQuery(name), "Query '%s' is already added", name);
namedQueries.put(name, withQuery);
return this;
}
public boolean containsNamedQuery(String name)
{
return namedQueries.containsKey(name);
}
public Scope build()
{
return new Scope(parent, queryBoundary, relationId, relationType, namedQueries);
}
}
}