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.om.functions.BuiltinFunctions;
  import org.apache.asterix.om.functions.ExternalFunctionInfo;
  import org.apache.asterix.om.typecomputer.base.TypeCastUtils;
  import org.apache.asterix.om.typecomputer.impl.TypeComputeUtils;
  import org.apache.asterix.om.types.ARecordType;
  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.commons.lang3.mutable.MutableObject;
  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.expressions.AbstractFunctionCallExpression;
  import org.apache.hyracks.algebricks.core.algebra.expressions.ScalarFunctionCallExpression;
  import org.apache.hyracks.algebricks.core.algebra.operators.logical.AbstractLogicalOperator;
  import org.apache.hyracks.algebricks.core.rewriter.base.IAlgebraicRewriteRule;
  
  /**
   * This rule provides the same type-casting handling as the IntroduceDynamicTypeCastRule does.
   * The only difference is that this rule is intended for external functions (User-Defined Functions).
   * Refer to IntroduceDynamicTypeCastRule for the detail.
   */
  public class IntroduceDynamicTypeCastForExternalFunctionRule implements IAlgebraicRewriteRule {
  
      @Override
      public boolean rewritePre(Mutable<ILogicalOperator> opRef, IOptimizationContext context)
              throws AlgebricksException {
          return false;
      }
  
      private boolean rewriteFunctionArgs(ILogicalOperator op, Mutable<ILogicalExpression> expRef,
              IOptimizationContext context) throws AlgebricksException {
          ILogicalExpression expr = expRef.getValue();
          if (expr.getExpressionTag() != LogicalExpressionTag.FUNCTION_CALL) {
              return false;
          }
          boolean changed = false;
          // go over all arguments recursively
          AbstractFunctionCallExpression funcCallExpr = (AbstractFunctionCallExpression) expr;
          for (Mutable<ILogicalExpression> functionArgRef : funcCallExpr.getArguments()) {
              if (rewriteFunctionArgs(op, functionArgRef, context)) {
                  changed = true;
              }
          }
          // if the current function is builtin function, skip the type casting
          if (BuiltinFunctions.getBuiltinFunctionInfo(funcCallExpr.getFunctionIdentifier()) != null) {
              return changed;
          }
          IAType inputType;
          IAType reqArgType;
          boolean castFlag;
          for (int i = 0; i < funcCallExpr.getArguments().size(); i++) {
              Mutable<ILogicalExpression> argExpr = funcCallExpr.getArguments().get(i);
              inputType = (IAType) op.computeOutputTypeEnvironment(context).getType(argExpr.getValue());
              reqArgType = ((ExternalFunctionInfo) funcCallExpr.getFunctionInfo()).getParameterTypes().get(i);
  
              if (reqArgType.getTypeTag() == ATypeTag.OBJECT) {
                  castFlag = !IntroduceDynamicTypeCastRule.compatible((ARecordType) reqArgType, inputType, op);
              } else if (reqArgType.getTypeTag() == ATypeTag.ANY) {
                  IAType inputPrimeType = TypeComputeUtils.getActualType(inputType);
                  castFlag = inputPrimeType.getTypeTag().isDerivedType();
              } else {
                  castFlag = !reqArgType.equals(inputType);
              }
              /**
               * the input record type can be an union type
               * for the case when it comes from a subplan or left-outer join
               */
              boolean checkUnknown = false;
              while (NonTaggedFormatUtil.isOptional(inputType)) {
                  /** while-loop for the case there is a nested multi-level union */
                  inputType = ((AUnionType) inputType).getActualType();
                  checkUnknown = true;
              }
              if (castFlag || checkUnknown) {
                  AbstractFunctionCallExpression castFunc = new ScalarFunctionCallExpression(
                          BuiltinFunctions.getBuiltinFunctionInfo(BuiltinFunctions.CAST_TYPE));
                  castFunc.setSourceLocation(argExpr.getValue().getSourceLocation());
                  castFunc.getArguments().add(argExpr);
                  TypeCastUtils.setRequiredAndInputTypes(castFunc, reqArgType, inputType);
                  funcCallExpr.getArguments().set(i, new MutableObject<>(castFunc));
                  changed = true;
              }
          }
          return changed;
      }
  
      @Override
      public boolean rewritePost(Mutable<ILogicalOperator> opRef, IOptimizationContext context)
              throws AlgebricksException {
          AbstractLogicalOperator op = (AbstractLogicalOperator) opRef.getValue();
          if (op.getOperatorTag() != LogicalOperatorTag.ASSIGN) {
              return false;
          }
          if (context.checkIfInDontApplySet(this, op)) {
              return false;
          }
          boolean applied = op.acceptExpressionTransform(expr -> rewriteFunctionArgs(op, expr, context));
          if (applied) {
              context.addToDontApplySet(this, op);
          }
          return applied;
      }
  }
  