ARROW-399: ListVector.loadFieldBuffers ignores the ArrowFieldNode len…

java/vector/src/main/codegen/templates/FixedValueVectors.java

@@ -45,6 +45,8 @@
 public final class ${minor.class}Vector extends BaseDataValueVector implements FixedWidthVector{
   private static final org.slf4j.Logger logger = org.slf4j.LoggerFactory.getLogger(${minor.class}Vector.class);
 
+  public static final int TYPE_WIDTH = ${type.width};
+
   private final Accessor accessor = new Accessor();
   private final Mutator mutator = new Mutator();
 

java/vector/src/main/codegen/templates/NullableValueVectors.java

@@ -37,7 +37,7 @@
 import org.apache.arrow.flatbuf.Precision;
 
 /**
- * Nullable${minor.class} implements a vector of values which could be null.  Elements in the vector
+ * ${className} implements a vector of values which could be null.  Elements in the vector
  * are first checked against a fixed length vector of boolean values.  Then the element is retrieved
  * from the base class (if not null).
  *
@@ -47,7 +47,7 @@
 public final class ${className} extends BaseDataValueVector implements <#if type.major == "VarLen">VariableWidth<#else>FixedWidth</#if>Vector, NullableVector, FieldVector {
   private static final org.slf4j.Logger logger = org.slf4j.LoggerFactory.getLogger(${className}.class);
 
-  private final FieldReader reader = new ${minor.class}ReaderImpl(Nullable${minor.class}Vector.this);
+  private final FieldReader reader = new ${minor.class}ReaderImpl(${className}.this);
 
   private final String bitsField = "$bits$";
   private final String valuesField = "$values$";
@@ -67,7 +67,7 @@ public final class ${className} extends BaseDataValueVector implements <#if type
 
   public ${className}(String name, BufferAllocator allocator, int precision, int scale) {
     super(name, allocator);
-    values = new ${minor.class}Vector(valuesField, allocator, precision, scale);
+    values = new ${valuesName}(valuesField, allocator, precision, scale);
     this.precision = precision;
     this.scale = scale;
     mutator = new Mutator();
@@ -81,7 +81,7 @@ public final class ${className} extends BaseDataValueVector implements <#if type
   <#else>
   public ${className}(String name, BufferAllocator allocator) {
     super(name, allocator);
-    values = new ${minor.class}Vector(valuesField, allocator);
+    values = new ${valuesName}(valuesField, allocator);
     mutator = new Mutator();
     accessor = new Accessor();
   <#if minor.class == "TinyInt" ||
@@ -144,6 +144,13 @@ public List<FieldVector> getChildrenFromFields() {
 
   @Override
   public void loadFieldBuffers(ArrowFieldNode fieldNode, List<ArrowBuf> ownBuffers) {
+    <#if type.major = "VarLen">
+    // variable width values: truncate offset vector buffer to size (#1)
+    org.apache.arrow.vector.BaseDataValueVector.truncateBufferBasedOnSize(ownBuffers, 1, values.offsetVector.getBufferSizeFor(fieldNode.getLength() + 1));
+    <#else>
+    // fixed width values truncate value vector to size (#1)
+    org.apache.arrow.vector.BaseDataValueVector.truncateBufferBasedOnSize(ownBuffers, 1, values.getBufferSizeFor(fieldNode.getLength()));
+    </#if>
     org.apache.arrow.vector.BaseDataValueVector.load(fieldNode, getFieldInnerVectors(), ownBuffers);
     bits.valueCount = fieldNode.getLength();
   }
@@ -229,13 +236,6 @@ public void setInitialCapacity(int numRecords) {
     values.setInitialCapacity(numRecords);
   }
 
-//  @Override
-//  public SerializedField.Builder getMetadataBuilder() {
-//    return super.getMetadataBuilder()
-//      .addChild(bits.getMetadata())
-//      .addChild(values.getMetadata());
-//  }
-
   @Override
   public void allocateNew() {
     if(!allocateNewSafe()){
@@ -329,20 +329,6 @@ public void zeroVector() {
   }
   </#if>
 
-
-//  @Override
-//  public void load(SerializedField metadata, ArrowBuf buffer) {
-//    clear();
-    // the bits vector is the first child (the order in which the children are added in getMetadataBuilder is significant)
-//    final SerializedField bitsField = metadata.getChild(0);
-//    bits.load(bitsField, buffer);
-//
-//    final int capacity = buffer.capacity();
-//    final int bitsLength = bitsField.getBufferLength();
-//    final SerializedField valuesField = metadata.getChild(1);
-//    values.load(valuesField, buffer.slice(bitsLength, capacity - bitsLength));
-//  }
-
   @Override
   public TransferPair getTransferPair(BufferAllocator allocator){
     return new TransferImpl(name, allocator);
@@ -356,10 +342,10 @@ public TransferPair getTransferPair(String ref, BufferAllocator allocator){
 
   @Override
   public TransferPair makeTransferPair(ValueVector to) {
-    return new TransferImpl((Nullable${minor.class}Vector) to);
+    return new TransferImpl((${className}) to);
   }
 
-  public void transferTo(Nullable${minor.class}Vector target){
+  public void transferTo(${className} target){
     bits.transferTo(target.bits);
     values.transferTo(target.values);
     <#if type.major == "VarLen">
@@ -368,7 +354,7 @@ public void transferTo(Nullable${minor.class}Vector target){
     clear();
   }
 
-  public void splitAndTransferTo(int startIndex, int length, Nullable${minor.class}Vector target) {
+  public void splitAndTransferTo(int startIndex, int length, ${className} target) {
     bits.splitAndTransferTo(startIndex, length, target.bits);
     values.splitAndTransferTo(startIndex, length, target.values);
     <#if type.major == "VarLen">
@@ -377,22 +363,22 @@ public void splitAndTransferTo(int startIndex, int length, Nullable${minor.class
   }
 
   private class TransferImpl implements TransferPair {
-    Nullable${minor.class}Vector to;
+    ${className} to;
 
     public TransferImpl(String name, BufferAllocator allocator){
       <#if minor.class == "Decimal">
-      to = new Nullable${minor.class}Vector(name, allocator, precision, scale);
+      to = new ${className}(name, allocator, precision, scale);
       <#else>
-      to = new Nullable${minor.class}Vector(name, allocator);
+      to = new ${className}(name, allocator);
       </#if>
     }
 
-    public TransferImpl(Nullable${minor.class}Vector to){
+    public TransferImpl(${className} to){
       this.to = to;
     }
 
     @Override
-    public Nullable${minor.class}Vector getTo(){
+    public ${className} getTo(){
       return to;
     }
 
@@ -408,7 +394,7 @@ public void splitAndTransfer(int startIndex, int length) {
 
     @Override
     public void copyValueSafe(int fromIndex, int toIndex) {
-      to.copyFromSafe(fromIndex, toIndex, Nullable${minor.class}Vector.this);
+      to.copyFromSafe(fromIndex, toIndex, ${className}.this);
     }
   }
 
@@ -422,22 +408,22 @@ public Mutator getMutator(){
     return mutator;
   }
 
-  public void copyFrom(int fromIndex, int thisIndex, Nullable${minor.class}Vector from){
+  public void copyFrom(int fromIndex, int thisIndex, ${className} from){
     final Accessor fromAccessor = from.getAccessor();
     if (!fromAccessor.isNull(fromIndex)) {
       mutator.set(thisIndex, fromAccessor.get(fromIndex));
     }
   }
 
-  public void copyFromSafe(int fromIndex, int thisIndex, ${minor.class}Vector from){
+  public void copyFromSafe(int fromIndex, int thisIndex, ${valuesName} from){
     <#if type.major == "VarLen">
     mutator.fillEmpties(thisIndex);
     </#if>
     values.copyFromSafe(fromIndex, thisIndex, from);
     bits.getMutator().setSafe(thisIndex, 1);
   }
 
-  public void copyFromSafe(int fromIndex, int thisIndex, Nullable${minor.class}Vector from){
+  public void copyFromSafe(int fromIndex, int thisIndex, ${className} from){
     <#if type.major == "VarLen">
     mutator.fillEmpties(thisIndex);
     </#if>
@@ -640,7 +626,7 @@ public void set(int index, ${minor.class}Holder holder){
     }
 
     public boolean isSafe(int outIndex) {
-      return outIndex < Nullable${minor.class}Vector.this.getValueCapacity();
+      return outIndex < ${className}.this.getValueCapacity();
     }
 
     <#assign fields = minor.fields!type.fields />

java/vector/src/main/codegen/templates/UnionVector.java

@@ -103,6 +103,8 @@ public List<FieldVector> getChildrenFromFields() {
 
   @Override
   public void loadFieldBuffers(ArrowFieldNode fieldNode, List<ArrowBuf> ownBuffers) {
+    // truncate types vector buffer to size (#0)
+    org.apache.arrow.vector.BaseDataValueVector.truncateBufferBasedOnSize(ownBuffers, 0, typeVector.getBufferSizeFor(fieldNode.getLength()));
     BaseDataValueVector.load(fieldNode, getFieldInnerVectors(), ownBuffers);
     this.valueCount = fieldNode.getLength();
   }

java/vector/src/main/java/org/apache/arrow/vector/BaseDataValueVector.java

@@ -30,6 +30,9 @@ public abstract class BaseDataValueVector extends BaseValueVector implements Buf
 
   protected final static byte[] emptyByteArray = new byte[]{}; // Nullable vectors use this
 
+  /** maximum extra size at the end of the buffer */
+  private static final int MAX_BUFFER_PADDING = 64;
+
   public static void load(ArrowFieldNode fieldNode, List<BufferBacked> vectors, List<ArrowBuf> buffers) {
     int expectedSize = vectors.size();
     if (buffers.size() != expectedSize) {
@@ -40,6 +43,20 @@ public static void load(ArrowFieldNode fieldNode, List<BufferBacked> vectors, Li
     }
   }
 
+  public static void truncateBufferBasedOnSize(List<ArrowBuf> buffers, int bufferIndex, int byteSize) {
+    if (bufferIndex >= buffers.size()) {
+      throw new IllegalArgumentException("no buffer at index " + bufferIndex + ": " + buffers);
+    }
+    ArrowBuf buffer = buffers.get(bufferIndex);
+    if (buffer.writerIndex() < byteSize) {
+      throw new IllegalArgumentException("can not truncate buffer to a larger size " + byteSize + ": " + buffer.writerIndex());
+    }
+    if (buffer.writerIndex() - byteSize > MAX_BUFFER_PADDING) {
+      throw new IllegalArgumentException("Buffer too large to resize to " + byteSize + ": " + buffer.writerIndex());
+    }
+    buffer.writerIndex(byteSize);
+  }
+
   public static List<ArrowBuf> unload(List<BufferBacked> vectors) {
     List<ArrowBuf> result = new ArrayList<>(vectors.size());
     for (BufferBacked vector : vectors) {

java/vector/src/main/java/org/apache/arrow/vector/BitVector.java

@@ -68,7 +68,7 @@ public void load(ArrowFieldNode fieldNode, ArrowBuf data) {
         int remainder = count % 8;
         // set remaining bits
         if (remainder > 0) {
-          byte bitMask = (byte) (0xFFL >>> ((8 - remainder) & 7));;
+          byte bitMask = (byte) (0xFFL >>> ((8 - remainder) & 7));
           this.data.setByte(fullBytesCount, bitMask);
         }
       } else if (fieldNode.getNullCount() == fieldNode.getLength()) {

java/vector/src/main/java/org/apache/arrow/vector/VectorLoader.java

@@ -82,7 +82,7 @@ private void loadBuffers(FieldVector vector, Field field, Iterator<ArrowBuf> buf
       vector.loadFieldBuffers(fieldNode, ownBuffers);
     } catch (RuntimeException e) {
       throw new IllegalArgumentException("Could not load buffers for field " +
-              field + " error message" + e.getMessage(), e);
+              field + ". error message: " + e.getMessage(), e);
     }
     List<Field> children = field.getChildren();
     if (children.size() > 0) {

java/vector/src/main/java/org/apache/arrow/vector/complex/ListVector.java

@@ -93,6 +93,8 @@ public List<FieldVector> getChildrenFromFields() {
 
   @Override
   public void loadFieldBuffers(ArrowFieldNode fieldNode, List<ArrowBuf> ownBuffers) {
+    // variable width values: truncate offset vector buffer to size (#1)
+    org.apache.arrow.vector.BaseDataValueVector.truncateBufferBasedOnSize(ownBuffers, 1, offsets.getBufferSizeFor(fieldNode.getLength() + 1));
     BaseDataValueVector.load(fieldNode, getFieldInnerVectors(), ownBuffers);
   }
 

java/vector/src/test/java/org/apache/arrow/vector/TestVectorUnloadLoad.java

@@ -23,6 +23,7 @@
 import static org.junit.Assert.assertTrue;
 
 import java.io.IOException;
+import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
 
@@ -32,6 +33,7 @@
 import org.apache.arrow.vector.complex.impl.ComplexWriterImpl;
 import org.apache.arrow.vector.complex.reader.FieldReader;
 import org.apache.arrow.vector.complex.writer.BaseWriter.ComplexWriter;
+import org.apache.arrow.vector.complex.writer.BaseWriter.ListWriter;
 import org.apache.arrow.vector.complex.writer.BaseWriter.MapWriter;
 import org.apache.arrow.vector.complex.writer.BigIntWriter;
 import org.apache.arrow.vector.complex.writer.IntWriter;
@@ -99,6 +101,79 @@ public void testUnloadLoad() throws IOException {
     }
   }
 
+  @Test
+  public void testUnloadLoadAddPadding() throws IOException {
+    int count = 10000;
+    Schema schema;
+    try (
+        BufferAllocator originalVectorsAllocator = allocator.newChildAllocator("original vectors", 0, Integer.MAX_VALUE);
+        MapVector parent = new MapVector("parent", originalVectorsAllocator, null)) {
+
+      // write some data
+      ComplexWriter writer = new ComplexWriterImpl("root", parent);
+      MapWriter rootWriter = writer.rootAsMap();
+      ListWriter list = rootWriter.list("list");
+      IntWriter intWriter = list.integer();
+      for (int i = 0; i < count; i++) {
+        list.setPosition(i);
+        list.startList();
+        for (int j = 0; j < i % 4 + 1; j++) {
+          intWriter.writeInt(i);
+        }
+        list.endList();
+      }
+      writer.setValueCount(count);
+
+      // unload it
+      FieldVector root = parent.getChild("root");
+      schema = new Schema(root.getField().getChildren());
+      VectorUnloader vectorUnloader = newVectorUnloader(root);
+      try (
+          ArrowRecordBatch recordBatch = vectorUnloader.getRecordBatch();
+          BufferAllocator finalVectorsAllocator = allocator.newChildAllocator("final vectors", 0, Integer.MAX_VALUE);
+          VectorSchemaRoot newRoot = new VectorSchemaRoot(schema, finalVectorsAllocator);
+          ) {
+        List<ArrowBuf> oldBuffers = recordBatch.getBuffers();
+        List<ArrowBuf> newBuffers = new ArrayList<>();
+        for (ArrowBuf oldBuffer : oldBuffers) {
+          int l = oldBuffer.readableBytes();
+          if (l % 64 != 0) {
+            // pad
+            l = l + 64 - l % 64;
+          }
+          ArrowBuf newBuffer = allocator.buffer(l);
+          for (int i = oldBuffer.readerIndex(); i < oldBuffer.writerIndex(); i++) {
+            newBuffer.setByte(i - oldBuffer.readerIndex(), oldBuffer.getByte(i));
+          }
+          newBuffer.readerIndex(0);
+          newBuffer.writerIndex(l);
+          newBuffers.add(newBuffer);
+        }
+
+        try (ArrowRecordBatch newBatch = new ArrowRecordBatch(recordBatch.getLength(), recordBatch.getNodes(), newBuffers);) {
+          // load it
+          VectorLoader vectorLoader = new VectorLoader(newRoot);
+
+          vectorLoader.load(newBatch);
+
+          FieldReader reader = newRoot.getVector("list").getReader();
+          for (int i = 0; i < count; i++) {
+            reader.setPosition(i);
+            List<Integer> expected = new ArrayList<>();
+            for (int j = 0; j < i % 4 + 1; j++) {
+              expected.add(i);
+            }
+            Assert.assertEquals(expected, reader.readObject());
+          }
+        }
+
+        for (ArrowBuf newBuf : newBuffers) {
+          newBuf.release();
+        }
+      }
+    }
+  }
+
   /**
    * The validity buffer can be empty if:
    *  - all values are defined
@@ -113,12 +188,17 @@ public void testLoadEmptyValidityBuffer() throws IOException {
         ));
     int count = 10;
     ArrowBuf validity = allocator.getEmpty();
-    ArrowBuf values = allocator.buffer(count * 4); // integers
-    for (int i = 0; i < count; i++) {
-      values.setInt(i * 4, i);
+    ArrowBuf[] values = new ArrowBuf[2];
+    for (int i = 0; i < values.length; i++) {
+      ArrowBuf arrowBuf = allocator.buffer(count * 4); // integers
+      values[i] = arrowBuf;
+      for (int j = 0; j < count; j++) {
+        arrowBuf.setInt(j * 4, j);
+      }
+      arrowBuf.writerIndex(count * 4);
     }
     try (
-        ArrowRecordBatch recordBatch = new ArrowRecordBatch(count, asList(new ArrowFieldNode(count, 0), new ArrowFieldNode(count, count)), asList(validity, values, validity, values));
+        ArrowRecordBatch recordBatch = new ArrowRecordBatch(count, asList(new ArrowFieldNode(count, 0), new ArrowFieldNode(count, count)), asList(validity, values[0], validity, values[1]));
         BufferAllocator finalVectorsAllocator = allocator.newChildAllocator("final vectors", 0, Integer.MAX_VALUE);
         VectorSchemaRoot newRoot = new VectorSchemaRoot(schema, finalVectorsAllocator);
         ) {
@@ -153,7 +233,9 @@ public void testLoadEmptyValidityBuffer() throws IOException {
       assertFalse(intDefinedVector.getAccessor().isNull(count + 10));
       assertEquals(1234, intDefinedVector.getAccessor().get(count + 10));
     } finally {
-      values.release();
+      for (ArrowBuf arrowBuf : values) {
+        arrowBuf.release();
+      }
     }
   }