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.memory.util.LargeMemoryUtil.checkedCastToInt;
  import static org.apache.arrow.util.Preconditions.checkNotNull;
  import static org.apache.arrow.util.Preconditions.checkState;
  
  import java.util.Collections;
  import java.util.List;
  import org.apache.arrow.memory.ArrowBuf;
  import org.apache.arrow.memory.BufferAllocator;
  import org.apache.arrow.util.Preconditions;
  import org.apache.arrow.vector.FieldVector;
  import org.apache.arrow.vector.dictionary.Dictionary;
  import org.apache.arrow.vector.dictionary.DictionaryProvider;
  import org.apache.arrow.vector.ipc.message.ArrowFieldNode;
  import org.apache.arrow.vector.types.pojo.DictionaryEncoding;
  
  /** Importer for {@link ArrowArray}. */
  final class ArrayImporter {
    private static final int MAX_IMPORT_RECURSION_LEVEL = 64;
  
    private final BufferAllocator allocator;
    private final FieldVector vector;
    private final DictionaryProvider dictionaryProvider;
  
    private ReferenceCountedArrowArray underlyingAllocation;
    private int recursionLevel;
  
    ArrayImporter(
        BufferAllocator allocator, FieldVector vector, DictionaryProvider dictionaryProvider) {
      this.allocator = Preconditions.checkNotNull(allocator);
      this.vector = Preconditions.checkNotNull(vector);
      this.dictionaryProvider = dictionaryProvider;
    }
  
    void importArray(ArrowArray src) {
      ArrowArray.Snapshot snapshot = src.snapshot();
      checkState(snapshot.release != NULL, "Cannot import released ArrowArray");
  
      // Move imported array
      ArrowArray ownedArray = ArrowArray.allocateNew(allocator);
      ownedArray.save(snapshot);
      src.markReleased();
  
      recursionLevel = 0;
  
      // This keeps the array alive as long as there are any buffers that need it
      underlyingAllocation = new ReferenceCountedArrowArray(ownedArray);
      try {
        doImport(snapshot);
      } finally {
        underlyingAllocation.release();
      }
    }
  
    private void importChild(ArrayImporter parent, ArrowArray src) {
      ArrowArray.Snapshot snapshot = src.snapshot();
      checkState(snapshot.release != NULL, "Cannot import released ArrowArray");
      recursionLevel = parent.recursionLevel + 1;
      checkState(
          recursionLevel <= MAX_IMPORT_RECURSION_LEVEL,
          "Recursion level in ArrowArray struct exceeded");
      // Child buffers will keep the entire parent import alive.
      underlyingAllocation = parent.underlyingAllocation;
      doImport(snapshot);
    }
  
    private void doImport(ArrowArray.Snapshot snapshot) {
      // First import children (required for reconstituting parent array data)
      long[] children =
          NativeUtil.toJavaArray(snapshot.children, checkedCastToInt(snapshot.n_children));
      if (children != null && children.length > 0) {
        List<FieldVector> childVectors = vector.getChildrenFromFields();
        checkState(
            children.length == childVectors.size(),
            "ArrowArray struct has %s children (expected %s)",
            children.length,
            childVectors.size());
        for (int i = 0; i < children.length; i++) {
          checkState(children[i] != NULL, "ArrowArray struct has NULL child at position %s", i);
          ArrayImporter childImporter =
              new ArrayImporter(allocator, childVectors.get(i), dictionaryProvider);
          childImporter.importChild(this, ArrowArray.wrap(children[i]));
        }
      }
  
      // Handle import of a dictionary encoded vector
      if (snapshot.dictionary != NULL) {
        DictionaryEncoding encoding = vector.getField().getDictionary();
        checkNotNull(encoding, "Missing encoding on import of ArrowArray with dictionary");
  
        Dictionary dictionary = dictionaryProvider.lookup(encoding.getId());
        checkNotNull(dictionary, "Dictionary lookup failed on import of ArrowArray with dictionary");
  
        // reset the dictionary vector to the initial state
        dictionary.getVector().clear();
  
        ArrayImporter dictionaryImporter =
            new ArrayImporter(allocator, dictionary.getVector(), dictionaryProvider);
        dictionaryImporter.importChild(this, ArrowArray.wrap(snapshot.dictionary));
      }
  
      // Import main data
      ArrowFieldNode fieldNode = new ArrowFieldNode(snapshot.length, snapshot.null_count);
      long[] bufferPointers =
          NativeUtil.toJavaArray(snapshot.buffers, checkedCastToInt(snapshot.n_buffers));
  
      try (final BufferImportTypeVisitor visitor =
          new BufferImportTypeVisitor(allocator, underlyingAllocation, fieldNode, bufferPointers)) {
        final List<ArrowBuf> buffers;
        if (bufferPointers == null || bufferPointers.length == 0) {
          buffers = Collections.emptyList();
        } else {
          buffers = vector.getField().getType().accept(visitor);
        }
        vector.loadFieldBuffers(fieldNode, buffers);
      } catch (Exception e) {
        throw new IllegalArgumentException(
            "Could not load buffers for field "
                + vector.getField()
                + ". error message: "
                + e.getMessage(),
            e);
      }
    }
  }
  