content: /*
   * Licensed to the Apache Software Foundation (ASF) under one
   * or more contributor license agreements.  See the NOTICE file
   * distributed with this work for additional information
   * regarding copyright ownership.  The ASF licenses this file
   * to you 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 org.apache.asterix.lang.sqlpp.visitor;
  
  import org.apache.asterix.common.exceptions.CompilationException;
  import org.apache.asterix.lang.common.base.ILangExpression;
  import org.apache.asterix.lang.common.base.IVisitorExtension;
  import org.apache.asterix.lang.common.clause.GroupbyClause;
  import org.apache.asterix.lang.common.clause.LetClause;
  import org.apache.asterix.lang.common.clause.LimitClause;
  import org.apache.asterix.lang.common.clause.OrderbyClause;
  import org.apache.asterix.lang.common.clause.WhereClause;
  import org.apache.asterix.lang.common.expression.CallExpr;
  import org.apache.asterix.lang.common.expression.FieldAccessor;
  import org.apache.asterix.lang.common.expression.IfExpr;
  import org.apache.asterix.lang.common.expression.IndexAccessor;
  import org.apache.asterix.lang.common.expression.ListConstructor;
  import org.apache.asterix.lang.common.expression.ListSliceExpression;
  import org.apache.asterix.lang.common.expression.LiteralExpr;
  import org.apache.asterix.lang.common.expression.OperatorExpr;
  import org.apache.asterix.lang.common.expression.QuantifiedExpression;
  import org.apache.asterix.lang.common.expression.RecordConstructor;
  import org.apache.asterix.lang.common.expression.UnaryExpr;
  import org.apache.asterix.lang.common.expression.VariableExpr;
  import org.apache.asterix.lang.common.statement.CopyToStatement;
  import org.apache.asterix.lang.common.statement.FunctionDecl;
  import org.apache.asterix.lang.common.statement.InsertStatement;
  import org.apache.asterix.lang.common.statement.Query;
  import org.apache.asterix.lang.common.struct.QuantifiedPair;
  import org.apache.asterix.lang.sqlpp.clause.FromClause;
  import org.apache.asterix.lang.sqlpp.clause.FromTerm;
  import org.apache.asterix.lang.sqlpp.clause.HavingClause;
  import org.apache.asterix.lang.sqlpp.clause.JoinClause;
  import org.apache.asterix.lang.sqlpp.clause.NestClause;
  import org.apache.asterix.lang.sqlpp.clause.Projection;
  import org.apache.asterix.lang.sqlpp.clause.SelectBlock;
  import org.apache.asterix.lang.sqlpp.clause.SelectClause;
  import org.apache.asterix.lang.sqlpp.clause.SelectElement;
  import org.apache.asterix.lang.sqlpp.clause.SelectRegular;
  import org.apache.asterix.lang.sqlpp.clause.SelectSetOperation;
  import org.apache.asterix.lang.sqlpp.clause.UnnestClause;
  import org.apache.asterix.lang.sqlpp.expression.CaseExpression;
  import org.apache.asterix.lang.sqlpp.expression.SelectExpression;
  import org.apache.asterix.lang.sqlpp.expression.WindowExpression;
  import org.apache.asterix.lang.sqlpp.util.SqlppVariableUtil;
  import org.apache.asterix.lang.sqlpp.visitor.base.AbstractSqlppQueryExpressionVisitor;
  
  /**
   * This class checks whether a reference to an undefined identifier (the second parameter of the visit method)
   * that is directly enclosed in the first parameter of the visit method should only be resolved to a dataset.
   */
  public final class CheckDatasetOnlyResolutionVisitor
          extends AbstractSqlppQueryExpressionVisitor<Boolean, VariableExpr> {
  
      public static final CheckDatasetOnlyResolutionVisitor INSTANCE = new CheckDatasetOnlyResolutionVisitor();
  
      private CheckDatasetOnlyResolutionVisitor() {
      }
  
      @Override
      public Boolean visit(FromTerm fromTerm, VariableExpr arg) throws CompilationException {
          return contains(fromTerm.getLeftExpression(), arg);
      }
  
      @Override
      public Boolean visit(JoinClause joinClause, VariableExpr arg) throws CompilationException {
          return contains(joinClause.getRightExpression(), arg);
      }
  
      @Override
      public Boolean visit(NestClause nestClause, VariableExpr arg) throws CompilationException {
          return contains(nestClause.getRightExpression(), arg);
      }
  
      @Override
      public Boolean visit(UnnestClause unnestClause, VariableExpr arg) throws CompilationException {
          return contains(unnestClause.getRightExpression(), arg);
      }
  
      @Override
      public Boolean visit(QuantifiedExpression qe, VariableExpr arg) throws CompilationException {
          for (QuantifiedPair qp : qe.getQuantifiedList()) {
              // If the target reference of undefined variable is a binding expression in a quantified pair,
              // then we only resolve it to dataset.
              if (contains(qp.getExpr(), arg)) {
                  return true;
              }
          }
          return false;
      }
  
      @Override
      public Boolean visit(CopyToStatement stmtCopy, VariableExpr arg) throws CompilationException {
          return contains(stmtCopy.getQuery(), arg);
      }
  
      @Override
      public Boolean visit(Query q, VariableExpr arg) throws CompilationException {
          return contains(q, arg);
      }
  
      @Override
      public Boolean visit(InsertStatement insert, VariableExpr arg) throws CompilationException {
          return false;
      }
  
      @Override
      public Boolean visit(FunctionDecl fd, VariableExpr arg) throws CompilationException {
          return false;
      }
  
      @Override
      public Boolean visit(LiteralExpr l, VariableExpr arg) throws CompilationException {
          return false;
      }
  
      @Override
      public Boolean visit(VariableExpr v, VariableExpr arg) throws CompilationException {
          return false;
      }
  
      @Override
      public Boolean visit(ListConstructor lc, VariableExpr arg) throws CompilationException {
          return false;
      }
  
      @Override
      public Boolean visit(RecordConstructor rc, VariableExpr arg) throws CompilationException {
          return false;
      }
  
      @Override
      public Boolean visit(OperatorExpr ifbo, VariableExpr arg) throws CompilationException {
          return false;
      }
  
      @Override
      public Boolean visit(FieldAccessor fa, VariableExpr arg) throws CompilationException {
          return false;
      }
  
      @Override
      public Boolean visit(IndexAccessor ia, VariableExpr arg) throws CompilationException {
          return false;
      }
  
      @Override
      public Boolean visit(ListSliceExpression expression, VariableExpr arg) throws CompilationException {
          return false;
      }
  
      @Override
      public Boolean visit(IVisitorExtension ve, VariableExpr arg) throws CompilationException {
          return ve.checkDatasetOnlyDispatch(this, arg);
      }
  
      @Override
      public Boolean visit(IfExpr ifexpr, VariableExpr arg) throws CompilationException {
          return false;
      }
  
      @Override
      public Boolean visit(UnaryExpr u, VariableExpr arg) throws CompilationException {
          return false;
      }
  
      @Override
      public Boolean visit(CallExpr pf, VariableExpr arg) throws CompilationException {
          return false;
      }
  
      @Override
      public Boolean visit(LetClause lc, VariableExpr arg) throws CompilationException {
          return false;
      }
  
      @Override
      public Boolean visit(WhereClause wc, VariableExpr arg) throws CompilationException {
          return false;
      }
  
      @Override
      public Boolean visit(OrderbyClause oc, VariableExpr arg) throws CompilationException {
          return false;
      }
  
      @Override
      public Boolean visit(GroupbyClause gc, VariableExpr arg) throws CompilationException {
          return false;
      }
  
      @Override
      public Boolean visit(LimitClause lc, VariableExpr arg) throws CompilationException {
          return false;
      }
  
      @Override
      public Boolean visit(FromClause fromClause, VariableExpr arg) throws CompilationException {
          return false;
      }
  
      @Override
      public Boolean visit(Projection projection, VariableExpr arg) throws CompilationException {
          return false;
      }
  
      @Override
      public Boolean visit(SelectBlock selectBlock, VariableExpr arg) throws CompilationException {
          return false;
      }
  
      @Override
      public Boolean visit(SelectClause selectClause, VariableExpr arg) throws CompilationException {
          return false;
      }
  
      @Override
      public Boolean visit(SelectElement selectElement, VariableExpr arg) throws CompilationException {
          return false;
      }
  
      @Override
      public Boolean visit(SelectRegular selectRegular, VariableExpr arg) throws CompilationException {
          return false;
      }
  
      @Override
      public Boolean visit(SelectSetOperation selectSetOperation, VariableExpr arg) throws CompilationException {
          return false;
      }
  
      @Override
      public Boolean visit(SelectExpression selectStatement, VariableExpr arg) throws CompilationException {
          return false;
      }
  
      @Override
      public Boolean visit(HavingClause havingClause, VariableExpr arg) throws CompilationException {
          return false;
      }
  
      @Override
      public Boolean visit(CaseExpression caseExpr, VariableExpr arg) throws CompilationException {
          return false;
      }
  
      @Override
      public Boolean visit(WindowExpression windowExpression, VariableExpr arg) throws CompilationException {
          return false;
      }
  
      private boolean contains(ILangExpression expr, VariableExpr var) throws CompilationException {
          return SqlppVariableUtil.getFreeVariables(expr).contains(var);
      }
  }
  