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 java.util.ArrayList;
  import java.util.List;
  
  import org.apache.asterix.algebra.operators.CommitOperator;
  import org.apache.asterix.metadata.declared.DataSource;
  import org.apache.asterix.om.typecomputer.base.TypeCastUtils;
  import org.apache.asterix.om.types.IAType;
  import org.apache.asterix.optimizer.rules.typecast.StaticTypeCastUtil;
  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.LogicalExpressionTag;
  import org.apache.hyracks.algebricks.core.algebra.base.LogicalOperatorTag;
  import org.apache.hyracks.algebricks.core.algebra.base.LogicalVariable;
  import org.apache.hyracks.algebricks.core.algebra.expressions.AbstractFunctionCallExpression;
  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.AssignOperator;
  import org.apache.hyracks.algebricks.core.algebra.operators.logical.DelegateOperator;
  import org.apache.hyracks.algebricks.core.algebra.operators.logical.InsertDeleteUpsertOperator;
  import org.apache.hyracks.algebricks.core.algebra.operators.logical.visitors.VariableUtilities;
  import org.apache.hyracks.algebricks.core.rewriter.base.IAlgebraicRewriteRule;
  
  /**
   * Statically cast a constant from its type to a specified required type, in a
   * recursive way. It enables: 1. bag-based fields in a record, 2. bidirectional
   * cast of an open field and a matched closed field, and 3. put in null fields
   * when necessary. It should be fired before the constant folding rule.
   * This rule is not responsible for type casting between primitive types.
   * Here is an example: A record { "hobby": {{"music", "coding"}}, "id": "001",
   * "name": "Person Three"} which confirms to closed type ( id: string, name:
   * string, hobby: {{string}}? ) can be cast to an open type (id: string ), or
   * vice versa.
   * Implementation wise: first, we match the record's type and its target dataset
   * type to see if it is "cast-able"; second, if the types are cast-able, we
   * embed the required type into the original producer expression. If the types
   * are not cast-able, we throw a compile time exception.
   * Then, at runtime (not in this rule), the corresponding record/list
   * constructors know what to do by checking the required output type.
   * TODO: right now record/list constructor of the cast result is not done in the
   * ConstantFoldingRule and has to go to the runtime, because the
   * ConstantFoldingRule uses ARecordSerializerDeserializer which seems to have
   * some problem.
   */
  public class IntroduceStaticTypeCastForInsertRule 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 {
          /**
           * pattern match: sink/insert/assign record type is propagated from
           * insert data source to the record-constructor expression
           */
          if (context.checkIfInDontApplySet(this, opRef.getValue())) {
              return false;
          }
          context.addToDontApplySet(this, opRef.getValue());
  
          AbstractLogicalOperator op1 = (AbstractLogicalOperator) opRef.getValue();
          List<LogicalVariable> producedVariables = new ArrayList<LogicalVariable>();
          LogicalVariable oldRecordVariable;
  
          if (op1.getOperatorTag() != LogicalOperatorTag.DELEGATE_OPERATOR
                  && op1.getOperatorTag() != LogicalOperatorTag.SINK) {
              return false;
          }
          if (op1.getOperatorTag() == LogicalOperatorTag.DELEGATE_OPERATOR) {
              DelegateOperator eOp = (DelegateOperator) op1;
              if (!(eOp.getDelegate() instanceof CommitOperator)) {
                  return false;
              }
          }
          AbstractLogicalOperator op2 = (AbstractLogicalOperator) op1.getInputs().get(0).getValue();
          if (op2.getOperatorTag() != LogicalOperatorTag.INSERT_DELETE_UPSERT) {
              return false;
          }
          InsertDeleteUpsertOperator insertDeleteOp = (InsertDeleteUpsertOperator) op2;
          if (insertDeleteOp.getOperation() == InsertDeleteUpsertOperator.Kind.DELETE) {
              return false;
          }
          /**
           * get required record type
           */
          InsertDeleteUpsertOperator insertDeleteOperator = (InsertDeleteUpsertOperator) op2;
          DataSource dataSource = (DataSource) insertDeleteOperator.getDataSource();
          IAType requiredRecordType = dataSource.getItemType();
  
          List<LogicalVariable> usedVariables = new ArrayList<LogicalVariable>();
          insertDeleteOperator.getPayloadExpression().getValue().getUsedVariables(usedVariables);
  
          // the used variable should contain the record that will be inserted
          // but it will not fail in many cases even if the used variable set is
          // empty
          if (usedVariables.size() == 0) {
              return false;
          }
  
          oldRecordVariable = usedVariables.get(0);
          LogicalVariable inputRecordVar = usedVariables.get(0);
          IVariableTypeEnvironment env = insertDeleteOperator.computeOutputTypeEnvironment(context);
          IAType inputRecordType = (IAType) env.getVarType(inputRecordVar);
  
          AbstractLogicalOperator currentOperator = (AbstractLogicalOperator) op2.getInputs().get(0).getValue();
          /**
           * find the assign operator for the "input record" to the insert_delete
           * operator
           */
          do {
              context.addToDontApplySet(this, currentOperator);
              if (currentOperator.getOperatorTag() == LogicalOperatorTag.ASSIGN) {
                  AssignOperator assignOp = (AssignOperator) currentOperator;
                  producedVariables.clear();
                  VariableUtilities.getProducedVariables(currentOperator, producedVariables);
                  int position = producedVariables.indexOf(oldRecordVariable);
  
                  /**
                   * set the top-down propagated type
                   */
                  if (position >= 0) {
                      AssignOperator originalAssign = (AssignOperator) currentOperator;
                      List<Mutable<ILogicalExpression>> expressionRefs = originalAssign.getExpressions();
                      ILogicalExpression expr = expressionRefs.get(position).getValue();
                      if (expr.getExpressionTag() == LogicalExpressionTag.FUNCTION_CALL) {
                          AbstractFunctionCallExpression funcExpr = (AbstractFunctionCallExpression) expr;
                          // that expression has been rewritten, and it will not
                          // fail but just return false
                          if (TypeCastUtils.getRequiredType(funcExpr) != null) {
                              context.computeAndSetTypeEnvironmentForOperator(assignOp);
                              return false;
                          }
                          IVariableTypeEnvironment assignEnv = assignOp.computeOutputTypeEnvironment(context);
                          StaticTypeCastUtil.rewriteFuncExpr(funcExpr, requiredRecordType, inputRecordType, assignEnv);
                      }
                      context.computeAndSetTypeEnvironmentForOperator(originalAssign);
                  }
              }
              if (currentOperator.getInputs().size() > 0) {
                  currentOperator = (AbstractLogicalOperator) currentOperator.getInputs().get(0).getValue();
              } else {
                  break;
              }
          } while (currentOperator != null);
          return true;
      }
  
  }
  