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.runtime.evaluators.functions;
  
  import java.util.List;
  
  import org.apache.asterix.common.annotations.MissingNullInOutFunction;
  import org.apache.asterix.om.functions.BuiltinFunctions;
  import org.apache.asterix.om.functions.IFunctionDescriptor;
  import org.apache.asterix.om.functions.IFunctionDescriptorFactory;
  import org.apache.asterix.om.functions.IFunctionTypeInferer;
  import org.apache.asterix.om.pointables.AListVisitablePointable;
  import org.apache.asterix.om.pointables.ARecordVisitablePointable;
  import org.apache.asterix.om.pointables.PointableAllocator;
  import org.apache.asterix.om.pointables.base.DefaultOpenFieldType;
  import org.apache.asterix.om.pointables.base.IVisitablePointable;
  import org.apache.asterix.om.types.AOrderedListType;
  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.AUnorderedListType;
  import org.apache.asterix.om.types.BuiltinType;
  import org.apache.asterix.om.types.IAType;
  import org.apache.asterix.runtime.evaluators.base.AbstractScalarFunctionDynamicDescriptor;
  import org.apache.asterix.runtime.functions.FunctionTypeInferers;
  import org.apache.hyracks.algebricks.core.algebra.functions.FunctionIdentifier;
  import org.apache.hyracks.algebricks.runtime.base.IScalarEvaluator;
  import org.apache.hyracks.algebricks.runtime.base.IScalarEvaluatorFactory;
  import org.apache.hyracks.api.context.IEvaluatorContext;
  import org.apache.hyracks.api.exceptions.HyracksDataException;
  import org.apache.hyracks.data.std.api.IPointable;
  import org.apache.hyracks.data.std.api.IValueReference;
  import org.apache.hyracks.data.std.primitive.VoidPointable;
  import org.apache.hyracks.dataflow.common.data.accessors.IFrameTupleReference;
  
  @MissingNullInOutFunction
  public class ToAtomicDescriptor extends AbstractScalarFunctionDynamicDescriptor {
      public static final IFunctionDescriptorFactory FACTORY = new IFunctionDescriptorFactory() {
          @Override
          public IFunctionDescriptor createFunctionDescriptor() {
              return new ToAtomicDescriptor();
          }
  
          @Override
          public IFunctionTypeInferer createFunctionTypeInferer() {
              return FunctionTypeInferers.SET_ARGUMENT_TYPE;
          }
      };
  
      private static final long serialVersionUID = 1L;
      private IAType argType;
  
      @Override
      public void setImmutableStates(Object... states) {
          argType = (IAType) states[0];
      }
  
      @Override
      public IScalarEvaluatorFactory createEvaluatorFactory(final IScalarEvaluatorFactory[] args) {
          return new IScalarEvaluatorFactory() {
              private static final long serialVersionUID = 1L;
  
              @Override
              public IScalarEvaluator createScalarEvaluator(final IEvaluatorContext ctx) throws HyracksDataException {
  
                  return new IScalarEvaluator() {
  
                      private final IScalarEvaluator eval0 = args[0].createScalarEvaluator(ctx);
                      private final IPointable arg = new VoidPointable();
  
                      private final PointableAllocator pAlloc = new PointableAllocator();
  
                      @Override
                      public void evaluate(IFrameTupleReference tuple, IPointable resultPointable)
                              throws HyracksDataException {
                          eval0.evaluate(tuple, arg);
  
                          if (PointableHelper.checkAndSetMissingOrNull(resultPointable, arg)) {
                              return;
                          }
  
                          IValueReference itemPtr = arg;
                          IAType itemTypeInferred = argType;
  
                          for (;;) {
                              byte[] itemData = itemPtr.getByteArray();
                              int itemOffset = itemPtr.getStartOffset();
                              ATypeTag typeTag = ATypeTag.VALUE_TYPE_MAPPING[itemData[itemOffset]];
                              switch (typeTag) {
                                  case ARRAY:
                                  case MULTISET:
                                      AListVisitablePointable listPointable =
                                              (AListVisitablePointable) allocatePointable(itemTypeInferred, typeTag);
                                      listPointable.set(itemPtr);
                                      List<IVisitablePointable> listItems = listPointable.getItems();
                                      if (listItems.size() != 1) {
                                          PointableHelper.setNull(resultPointable);
                                          return;
                                      }
                                      itemPtr = listItems.get(0);
                                      itemTypeInferred = getListItemType(itemTypeInferred);
                                      break;
                                  case OBJECT:
                                      ARecordType recType = asRecordType(itemTypeInferred);
                                      ARecordVisitablePointable recPointable =
                                              (ARecordVisitablePointable) allocatePointable(itemTypeInferred, typeTag);
                                      recPointable.set(itemPtr);
                                      List<IVisitablePointable> recValues = recPointable.getFieldValues();
                                      if (recValues.size() != 1) {
                                          PointableHelper.setNull(resultPointable);
                                          return;
                                      }
                                      itemPtr = recValues.get(0);
                                      itemTypeInferred = recType.getFieldTypes().length == 1 ? recType.getFieldTypes()[0]
                                              : BuiltinType.ANY;
                                      break;
                                  default:
                                      resultPointable.set(itemPtr);
                                      return;
                              }
                          }
                      }
  
                      private IVisitablePointable allocatePointable(IAType inferredType, ATypeTag actualTypeTag) {
                          if (inferredType.equals(BuiltinType.ANY)) {
                              return allocatePointableForAny(actualTypeTag);
                          }
                          return pAlloc.allocateFieldValue(inferredType);
                      }
  
                      private IVisitablePointable allocatePointableForAny(ATypeTag typeTag) {
                          switch (typeTag) {
                              case OBJECT:
                                  return pAlloc.allocateFieldValue(DefaultOpenFieldType.NESTED_OPEN_RECORD_TYPE);
                              case ARRAY:
                                  return pAlloc.allocateFieldValue(DefaultOpenFieldType.NESTED_OPEN_AORDERED_LIST_TYPE);
                              case MULTISET:
                                  return pAlloc.allocateFieldValue(DefaultOpenFieldType.NESTED_OPEN_AUNORDERED_LIST_TYPE);
                              default:
                                  return pAlloc.allocateFieldValue(null);
                          }
                      }
  
                      private ARecordType asRecordType(IAType inferredType) {
                          switch (inferredType.getTypeTag()) {
                              case OBJECT:
                                  return (ARecordType) inferredType;
                              case UNION:
                                  IAType innerType = ((AUnionType) inferredType).getActualType();
                                  if (innerType.getTypeTag() == ATypeTag.OBJECT) {
                                      return (ARecordType) innerType;
                                  }
                          }
                          return DefaultOpenFieldType.NESTED_OPEN_RECORD_TYPE;
                      }
  
                      private IAType getListItemType(IAType inferredType) {
                          switch (inferredType.getTypeTag()) {
                              case ARRAY:
                                  return ((AOrderedListType) inferredType).getItemType();
                              case MULTISET:
                                  return ((AUnorderedListType) inferredType).getItemType();
                              case UNION:
                                  IAType innerType = ((AUnionType) inferredType).getActualType();
                                  switch (innerType.getTypeTag()) {
                                      case ARRAY:
                                          return ((AOrderedListType) innerType).getItemType();
                                      case MULTISET:
                                          return ((AUnorderedListType) innerType).getItemType();
                                  }
                          }
                          return BuiltinType.ANY;
                      }
                  };
              }
          };
      }
  
      @Override
      public FunctionIdentifier getIdentifier() {
          return BuiltinFunctions.TO_ATOMIC;
      }
  }
  