Copilot commented on code in PR #303:
URL: https://github.com/apache/arrow-dotnet/pull/303#discussion_r3012923108
##########
src/Apache.Arrow/C/CArrowArrayImporter.cs:
##########
@@ -393,6 +397,32 @@ private ArrowBuffer[] ImportListViewBuffers(CArrowArray*
cArray)
return buffers;
}
+ private ArrowBuffer[] ImportLargeListViewBuffers(CArrowArray*
cArray)
+ {
+ if (cArray->n_buffers != 3)
+ {
+ throw new InvalidOperationException("Large list view
arrays are expected to have exactly three buffers");
+ }
+
+ const int maxLength = int.MaxValue / 8;
+ if (cArray->length > maxLength)
+ {
+ throw new OverflowException(
+ $"Cannot import large list view array. Array length
{cArray->length} " +
+ $"is greater than the maximum supported large list
view array length ({maxLength})");
+ }
+
+ int length = checked((int)cArray->offset +
(int)cArray->length);
+ int bufferLength = length * 8;
+
+ ArrowBuffer[] buffers = new ArrowBuffer[3];
+ buffers[0] = ImportValidityBuffer(cArray);
Review Comment:
`bufferLength = length * 8` can overflow when `cArray->offset` is large even
if `cArray->length` passes the current `maxLength` check (since `length`
includes `offset + length`). If this overflows negative, `ImportCArrayBuffer`
will return `ArrowBuffer.Empty` and the imported array data will be corrupted
instead of throwing. Consider validating the combined `length` (offset+length)
against `int.MaxValue / 8` (or using `checked(length * 8)`) and throwing an
`OverflowException` when it exceeds the supported range.
##########
src/Apache.Arrow/Arrays/LargeListViewArray.cs:
##########
@@ -0,0 +1,216 @@
+// 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.
+
+using System;
+using Apache.Arrow.Memory;
+using Apache.Arrow.Types;
+
+namespace Apache.Arrow
+{
+ public class LargeListViewArray : Array
+ {
+ public class Builder : IArrowArrayBuilder<LargeListViewArray, Builder>
+ {
+ public IArrowArrayBuilder<IArrowArray,
IArrowArrayBuilder<IArrowArray>> ValueBuilder { get; }
+
+ public int Length => ValueOffsetsBufferBuilder.Length;
+
+ private ArrowBuffer.Builder<long> ValueOffsetsBufferBuilder { get;
}
+
+ private ArrowBuffer.Builder<long> SizesBufferBuilder { get; }
+
+ private ArrowBuffer.BitmapBuilder ValidityBufferBuilder { get; }
+
+ public int NullCount { get; protected set; }
+
+ private IArrowType DataType { get; }
+
+ private int Start { get; set; }
+
+ public Builder(IArrowType valueDataType) : this(new
LargeListViewType(valueDataType))
+ {
+ }
+
+ public Builder(Field valueField) : this(new
LargeListViewType(valueField))
+ {
+ }
+
+ internal Builder(LargeListViewType dataType)
+ {
+ ValueBuilder =
ArrowArrayBuilderFactory.Build(dataType.ValueDataType);
+ ValueOffsetsBufferBuilder = new ArrowBuffer.Builder<long>();
+ SizesBufferBuilder = new ArrowBuffer.Builder<long>();
+ ValidityBufferBuilder = new ArrowBuffer.BitmapBuilder();
+ DataType = dataType;
+ Start = -1;
+ }
+
+ /// <summary>
+ /// Start a new variable-length list slot
+ ///
+ /// This function should be called before beginning to append
elements to the
+ /// value builder.
+ /// </summary>
+ public Builder Append()
+ {
+ AppendPrevious();
+
+ ValidityBufferBuilder.Append(true);
+
+ return this;
+ }
+
+ public Builder AppendNull()
+ {
+ AppendPrevious();
+
+ ValidityBufferBuilder.Append(false);
+ ValueOffsetsBufferBuilder.Append(Start);
+ SizesBufferBuilder.Append(0);
+ NullCount++;
+ Start = -1;
+
+ return this;
+ }
+
+ private void AppendPrevious()
+ {
+ if (Start >= 0)
+ {
+ ValueOffsetsBufferBuilder.Append(Start);
+ SizesBufferBuilder.Append(ValueBuilder.Length - Start);
+ }
+ Start = ValueBuilder.Length;
+ }
+
+ public LargeListViewArray Build(MemoryAllocator allocator =
default)
+ {
+ AppendPrevious();
+
+ ArrowBuffer validityBuffer = NullCount > 0
+ ?
ValidityBufferBuilder.Build(allocator)
+ : ArrowBuffer.Empty;
+
+ return new LargeListViewArray(DataType, Length,
+ ValueOffsetsBufferBuilder.Build(allocator),
SizesBufferBuilder.Build(allocator),
+ ValueBuilder.Build(allocator),
+ validityBuffer, NullCount, 0);
+ }
+
+ public Builder Reserve(int capacity)
+ {
+ ValueOffsetsBufferBuilder.Reserve(capacity);
+ SizesBufferBuilder.Reserve(capacity);
+ ValidityBufferBuilder.Reserve(capacity);
+ return this;
+ }
+
+ public Builder Resize(int length)
+ {
+ ValueOffsetsBufferBuilder.Resize(length);
+ SizesBufferBuilder.Resize(length);
+ ValidityBufferBuilder.Resize(length);
+ return this;
+ }
+
+ public Builder Clear()
+ {
+ ValueOffsetsBufferBuilder.Clear();
+ SizesBufferBuilder.Clear();
+ ValueBuilder.Clear();
+ ValidityBufferBuilder.Clear();
+ NullCount = 0;
Review Comment:
`Clear()` doesn't reset the internal `Start` cursor. If the builder is
cleared after `Build()` (or after an `Append()` that hasn't been closed),
`Start` can remain >= 0 while `ValueBuilder.Length` is reset to 0, and the next
`AppendPrevious()` will append an invalid (potentially negative) size.
Resetting `Start` (e.g., back to -1) as part of `Clear()` would make the
builder safe to reuse after any state.
```suggestion
NullCount = 0;
Start = -1;
```
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