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.arrow.c;
  
  import static org.apache.arrow.c.NativeUtil.NULL;
  import static org.apache.arrow.util.Preconditions.checkState;
  
  import java.io.IOException;
  import java.util.Map;
  import java.util.function.Function;
  import java.util.stream.Collectors;
  import org.apache.arrow.memory.BufferAllocator;
  import org.apache.arrow.vector.dictionary.Dictionary;
  import org.apache.arrow.vector.ipc.ArrowReader;
  import org.apache.arrow.vector.types.pojo.Schema;
  
  /** An implementation of an {@link ArrowReader} backed by an ArrowArrayStream. */
  final class ArrowArrayStreamReader extends ArrowReader {
    private final ArrowArrayStream ownedStream;
    private final CDataDictionaryProvider provider;
  
    ArrowArrayStreamReader(BufferAllocator allocator, ArrowArrayStream stream) {
      super(allocator);
      this.provider = new CDataDictionaryProvider();
  
      ArrowArrayStream.Snapshot snapshot = stream.snapshot();
      checkState(snapshot.release != NULL, "Cannot import released ArrowArrayStream");
  
      // Move imported stream
      this.ownedStream = ArrowArrayStream.allocateNew(allocator);
      this.ownedStream.save(snapshot);
      stream.markReleased();
    }
  
    @Override
    public Map<Long, Dictionary> getDictionaryVectors() {
      return provider.getDictionaryIds().stream()
          .collect(Collectors.toMap(Function.identity(), provider::lookup));
    }
  
    @Override
    public Dictionary lookup(long id) {
      return provider.lookup(id);
    }
  
    @Override
    public boolean loadNextBatch() throws IOException {
      try (ArrowArray array = ArrowArray.allocateNew(allocator)) {
        ownedStream.getNext(array);
        if (array.snapshot().release == NULL) {
          return false;
        }
        Data.importIntoVectorSchemaRoot(allocator, array, getVectorSchemaRoot(), provider);
        return true;
      }
    }
  
    @Override
    public long bytesRead() {
      return 0;
    }
  
    @Override
    protected void closeReadSource() {
      ownedStream.release();
      ownedStream.close();
      provider.close();
    }
  
    @Override
    protected Schema readSchema() throws IOException {
      try (ArrowSchema schema = ArrowSchema.allocateNew(allocator)) {
        ownedStream.getSchema(schema);
        return Data.importSchema(allocator, schema, provider);
      }
    }
  }
  