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.optimizer.rules;
  
  import org.apache.asterix.common.exceptions.CompilationException;
  import org.apache.asterix.common.exceptions.ErrorCode;
  import org.apache.asterix.om.types.ATypeTag;
  import org.apache.asterix.om.types.AUnionType;
  import org.apache.asterix.om.types.IAType;
  import org.apache.asterix.om.utils.NonTaggedFormatUtil;
  import org.apache.commons.lang3.mutable.Mutable;
  import org.apache.hyracks.algebricks.common.exceptions.AlgebricksException;
  import org.apache.hyracks.algebricks.core.algebra.base.ILogicalExpression;
  import org.apache.hyracks.algebricks.core.algebra.base.ILogicalOperator;
  import org.apache.hyracks.algebricks.core.algebra.base.IOptimizationContext;
  import org.apache.hyracks.algebricks.core.algebra.base.LogicalOperatorTag;
  import org.apache.hyracks.algebricks.core.algebra.expressions.IVariableTypeEnvironment;
  import org.apache.hyracks.algebricks.core.algebra.operators.logical.AbstractLogicalOperator;
  import org.apache.hyracks.algebricks.core.algebra.operators.logical.SelectOperator;
  import org.apache.hyracks.algebricks.core.rewriter.base.IAlgebraicRewriteRule;
  import org.apache.hyracks.util.LogRedactionUtil;
  
  /**
   * This rule is to check if all the filter expression are of the boolean type or a possible (determined
   * at the runtime) boolean type.
   * If that is not the case, an exception should be thrown.
   *
   * @author yingyib
   */
  public class CheckFilterExpressionTypeRule implements IAlgebraicRewriteRule {
  
      @Override
      public boolean rewritePre(Mutable<ILogicalOperator> opRef, IOptimizationContext context)
              throws AlgebricksException {
          return false;
      }
  
      @Override
      public boolean rewritePost(Mutable<ILogicalOperator> opRef, IOptimizationContext context)
              throws AlgebricksException {
          AbstractLogicalOperator op = (AbstractLogicalOperator) opRef.getValue();
          if (op.getOperatorTag() != LogicalOperatorTag.SELECT) {
              return false;
          }
          SelectOperator select = (SelectOperator) op;
          ILogicalExpression condition = select.getCondition().getValue();
  
          // Get the output type environment
          IVariableTypeEnvironment env = context.getOutputTypeEnvironment(select);
  
          IAType condType = (IAType) env.getType(condition);
          if (condType.getTypeTag() != ATypeTag.BOOLEAN && condType.getTypeTag() != ATypeTag.ANY
                  && !isPossibleBoolean(condType)) {
              throw new CompilationException(ErrorCode.COMPILATION_ERROR, condition.getSourceLocation(),
                      "The select condition " + LogRedactionUtil.userData(condition.toString()) + " should be of the "
                              + "boolean type.");
          }
          return false;
      }
  
      /**
       * Check if the type is optional boolean or not
       *
       * @param type
       * @return true if it is; false otherwise.
       */
      private boolean isPossibleBoolean(IAType type) {
          IAType checkingType = type;
          while (NonTaggedFormatUtil.isOptional(checkingType)) {
              IAType actualType = ((AUnionType) checkingType).getActualType();
              if (actualType.getTypeTag() == ATypeTag.BOOLEAN || actualType.getTypeTag() == ATypeTag.ANY) {
                  return true;
              }
              checkingType = actualType;
          }
          return false;
      }
  
  }
  