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.records;
  
  import java.io.DataOutput;
  import java.io.IOException;
  
  import org.apache.asterix.dataflow.data.nontagged.serde.ARecordSerializerDeserializer;
  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.asterix.om.utils.RecordUtil;
  import org.apache.asterix.runtime.evaluators.functions.PointableHelper;
  import org.apache.asterix.runtime.exceptions.TypeMismatchException;
  import org.apache.hyracks.algebricks.common.exceptions.NotImplementedException;
  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.api.exceptions.SourceLocation;
  import org.apache.hyracks.data.std.api.IPointable;
  import org.apache.hyracks.data.std.primitive.IntegerPointable;
  import org.apache.hyracks.data.std.primitive.VoidPointable;
  import org.apache.hyracks.data.std.util.ArrayBackedValueStorage;
  import org.apache.hyracks.dataflow.common.data.accessors.IFrameTupleReference;
  
  public class FieldAccessByIndexEvalFactory implements IScalarEvaluatorFactory {
  
      private static final long serialVersionUID = 1L;
      private final IScalarEvaluatorFactory recordEvalFactory;
      private final IScalarEvaluatorFactory fieldIndexEvalFactory;
      private final int nullBitmapSize;
      private final ARecordType recordType;
      private final SourceLocation sourceLoc;
  
      FieldAccessByIndexEvalFactory(IScalarEvaluatorFactory recordEvalFactory,
              IScalarEvaluatorFactory fieldIndexEvalFactory, ARecordType recordType, SourceLocation sourceLoc) {
          this.recordEvalFactory = recordEvalFactory;
          this.fieldIndexEvalFactory = fieldIndexEvalFactory;
          this.recordType = recordType;
          this.nullBitmapSize = recordType != null ? RecordUtil.computeNullBitmapSize(recordType) : 0;
          this.sourceLoc = sourceLoc;
      }
  
      @Override
      public IScalarEvaluator createScalarEvaluator(final IEvaluatorContext ctx) throws HyracksDataException {
          return new IScalarEvaluator() {
              private final ArrayBackedValueStorage resultStorage = new ArrayBackedValueStorage();
              private final DataOutput out = resultStorage.getDataOutput();
              private final IPointable inputArg0 = new VoidPointable();
              private final IPointable inputArg1 = new VoidPointable();
              private final IScalarEvaluator eval0 = recordEvalFactory.createScalarEvaluator(ctx);
              private final IScalarEvaluator eval1 = fieldIndexEvalFactory.createScalarEvaluator(ctx);
              private int fieldIndex;
              private int fieldValueOffset;
              private int fieldValueLength;
              private IAType fieldValueType;
              private ATypeTag fieldValueTypeTag;
  
              // inputArg0: the record, inputArg1: the index
              @Override
              public void evaluate(IFrameTupleReference tuple, IPointable result) throws HyracksDataException {
                  try {
                      resultStorage.reset();
                      eval0.evaluate(tuple, inputArg0);
                      eval1.evaluate(tuple, inputArg1);
  
                      if (PointableHelper.checkAndSetMissingOrNull(result, inputArg0, inputArg1)) {
                          return;
                      }
  
                      byte[] serRecord = inputArg0.getByteArray();
                      int offset = inputArg0.getStartOffset();
                      byte[] indexBytes = inputArg1.getByteArray();
                      int indexOffset = inputArg1.getStartOffset();
  
                      if (serRecord[offset] != ATypeTag.SERIALIZED_RECORD_TYPE_TAG || recordType == null) {
                          // recordType = null should only mean first arg was not a record and compiler couldn't set it
                          throw new TypeMismatchException(sourceLoc, serRecord[offset],
                                  ATypeTag.SERIALIZED_RECORD_TYPE_TAG);
                      }
  
                      if (indexBytes[indexOffset] != ATypeTag.SERIALIZED_INT32_TYPE_TAG) {
                          throw new TypeMismatchException(sourceLoc, indexBytes[offset],
                                  ATypeTag.SERIALIZED_INT32_TYPE_TAG);
                      }
                      fieldIndex = IntegerPointable.getInteger(indexBytes, indexOffset + 1);
                      fieldValueType = recordType.getFieldTypes()[fieldIndex];
                      fieldValueOffset = ARecordSerializerDeserializer.getFieldOffsetById(serRecord, offset, fieldIndex,
                              nullBitmapSize, recordType.isOpen());
  
                      if (fieldValueOffset == 0) {
                          // the field is null, we checked the null bit map
                          out.writeByte(ATypeTag.SERIALIZED_NULL_TYPE_TAG);
                          result.set(resultStorage);
                          return;
                      }
                      if (fieldValueOffset < 0) {
                          // the field is missing, we checked the missing bit map
                          out.writeByte(ATypeTag.SERIALIZED_MISSING_TYPE_TAG);
                          result.set(resultStorage);
                          return;
                      }
  
                      if (fieldValueType.getTypeTag().equals(ATypeTag.UNION)) {
                          if (((AUnionType) fieldValueType).isUnknownableType()) {
                              fieldValueTypeTag = ((AUnionType) fieldValueType).getActualType().getTypeTag();
                              fieldValueLength = NonTaggedFormatUtil.getFieldValueLength(serRecord, fieldValueOffset,
                                      fieldValueTypeTag, false);
                              out.writeByte(fieldValueTypeTag.serialize());
                          } else {
                              // union .. the general case
                              throw new NotImplementedException();
                          }
                      } else {
                          fieldValueTypeTag = fieldValueType.getTypeTag();
                          fieldValueLength = NonTaggedFormatUtil.getFieldValueLength(serRecord, fieldValueOffset,
                                  fieldValueTypeTag, false);
                          out.writeByte(fieldValueTypeTag.serialize());
                      }
                      out.write(serRecord, fieldValueOffset, fieldValueLength);
                      result.set(resultStorage);
                  } catch (IOException e) {
                      throw HyracksDataException.create(e);
                  }
              }
          };
      }
  }
  