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Posted to github@arrow.apache.org by "eerhardt (via GitHub)" <gi...@apache.org> on 2023/05/10 02:50:10 UTC
[GitHub] [arrow] eerhardt commented on a diff in pull request #35496: GH-33856: [C#] Implement C Data Interface for C#
eerhardt commented on code in PR #35496:
URL: https://github.com/apache/arrow/pull/35496#discussion_r1189289825
##########
csharp/src/Apache.Arrow/C/CArrowArrayExporter.cs:
##########
@@ -0,0 +1,210 @@
+// 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 System.Runtime.InteropServices;
+using Apache.Arrow.Memory;
+
+namespace Apache.Arrow.C
+{
+ public static class CArrowArrayExporter
+ {
+ private unsafe delegate void ReleaseArrowArray(CArrowArray* cArray);
+
+ /// <summary>
+ /// Export an <see cref="IArrowArray"/> to a <see cref="CArrowArray"/>. Whether or not the
+ /// export succeeds, the original array becomes invalid. Clone an array to continue using it
+ /// after a copy has been exported.
+ /// </summary>
+ /// <param name="array">The array to export</param>
+ /// <param name="cArray">An allocated but uninitialized CArrowArray pointer.</param>
+ /// <example>
+ /// <code>
+ /// CArrowArray* exportPtr = CArrowArray.Create();
+ /// CArrowArrayExporter.ExportArray(array, exportPtr);
+ /// foreign_import_function(exportPtr);
+ /// </code>
+ /// </example>
+ public static unsafe void ExportArray(IArrowArray array, CArrowArray* cArray)
+ {
+ if (array == null)
+ {
+ throw new ArgumentNullException(nameof(array));
+ }
+ if (cArray == null)
+ {
+ throw new ArgumentNullException(nameof(cArray));
+ }
+ if (cArray->release != null)
+ {
+ throw new ArgumentException("Cannot export array to a struct that is already initialized.", nameof(cArray));
+ }
+
+ ExportedAllocationOwner allocationOwner = new ExportedAllocationOwner();
+ try
+ {
+ ConvertArray(allocationOwner, array.Data, cArray);
+ cArray->release = (delegate* unmanaged[Stdcall]<CArrowArray*, void>)Marshal.GetFunctionPointerForDelegate<ReleaseArrowArray>(ReleaseArray);
Review Comment:
I think we can do this another way. If you add `[UnmanagedCallersOnly]` to the `private unsafe static void ReleaseArray(CArrowArray* cArray)` method, then this line should just be:
```suggestion
cArray->release = (delegate* unmanaged[Stdcall]<CArrowArray*, void>)&ReleaseArray;
```
##########
csharp/src/Apache.Arrow/Arrays/ArrowArrayFactory.cs:
##########
@@ -25,6 +25,8 @@ public static IArrowArray BuildArray(ArrayData data)
{
switch (data.DataType.TypeId)
{
+ case ArrowTypeId.Null:
Review Comment:
Can we add some tests for the Null array?
##########
csharp/src/Apache.Arrow/Memory/ExportedAllocationOwner.cs:
##########
@@ -0,0 +1,55 @@
+// 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 System.Collections.Generic;
+using System.Runtime.InteropServices;
+
+namespace Apache.Arrow.Memory
+{
+ internal sealed class ExportedAllocationOwner : INativeAllocationOwner, IDisposable
+ {
+ private readonly List<IntPtr> _pointers = new List<IntPtr>();
+ private int _allocationSize;
+
+ ~ExportedAllocationOwner()
+ {
+ Dispose();
Review Comment:
This should implement the Disposable pattern.
https://learn.microsoft.com/en-us/dotnet/standard/garbage-collection/implementing-dispose
##########
csharp/src/Apache.Arrow/Arrays/ArrowArrayFactory.cs:
##########
@@ -25,6 +25,8 @@ public static IArrowArray BuildArray(ArrayData data)
{
switch (data.DataType.TypeId)
{
+ case ArrowTypeId.Null:
Review Comment:
We should also update
https://github.com/apache/arrow/blob/122fc86576b03ebd130e027200c5eda6a185d2ee/docs/source/status.rst?plain=1#L32-L35
for this new functionality.
We should also turn on this integration test as well:
https://github.com/apache/arrow/blob/122fc86576b03ebd130e027200c5eda6a185d2ee/dev/archery/archery/integration/datagen.py#L1672-L1673
##########
csharp/src/Apache.Arrow/Memory/NativeMemoryManager.cs:
##########
@@ -64,20 +72,36 @@ public override void Unpin()
protected override void Dispose(bool disposing)
{
// Only free once.
+ IntPtr ptr = Interlocked.Exchange(ref _ptr, IntPtr.Zero);
+ if (ptr != IntPtr.Zero)
+ {
+ _owner.Release(ptr, _offset, _length);
+ }
+ }
- lock (this)
+ bool IOwnableAllocation.TryAcquire(out IntPtr ptr, out int offset, out int length)
+ {
+ // TODO: implement refcounted buffers?
Review Comment:
Will this get addressed in this PR? If not, we should open an issue for it.
##########
csharp/test/Apache.Arrow.Tests/CDataInterfacePythonTests.cs:
##########
@@ -166,6 +169,79 @@ private static dynamic GetPythonSchema()
}
}
+ private IArrowArray GetTestArray()
Review Comment:
Can we add some tests using the TestData that has all types?
##########
csharp/src/Apache.Arrow/C/CArrowArrayExporter.cs:
##########
@@ -0,0 +1,210 @@
+// 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 System.Runtime.InteropServices;
+using Apache.Arrow.Memory;
+
+namespace Apache.Arrow.C
+{
+ public static class CArrowArrayExporter
+ {
+ private unsafe delegate void ReleaseArrowArray(CArrowArray* cArray);
+
+ /// <summary>
+ /// Export an <see cref="IArrowArray"/> to a <see cref="CArrowArray"/>. Whether or not the
+ /// export succeeds, the original array becomes invalid. Clone an array to continue using it
+ /// after a copy has been exported.
+ /// </summary>
+ /// <param name="array">The array to export</param>
+ /// <param name="cArray">An allocated but uninitialized CArrowArray pointer.</param>
+ /// <example>
+ /// <code>
+ /// CArrowArray* exportPtr = CArrowArray.Create();
+ /// CArrowArrayExporter.ExportArray(array, exportPtr);
+ /// foreign_import_function(exportPtr);
+ /// </code>
+ /// </example>
+ public static unsafe void ExportArray(IArrowArray array, CArrowArray* cArray)
+ {
+ if (array == null)
+ {
+ throw new ArgumentNullException(nameof(array));
+ }
+ if (cArray == null)
+ {
+ throw new ArgumentNullException(nameof(cArray));
+ }
+ if (cArray->release != null)
+ {
+ throw new ArgumentException("Cannot export array to a struct that is already initialized.", nameof(cArray));
+ }
+
+ ExportedAllocationOwner allocationOwner = new ExportedAllocationOwner();
+ try
+ {
+ ConvertArray(allocationOwner, array.Data, cArray);
+ cArray->release = (delegate* unmanaged[Stdcall]<CArrowArray*, void>)Marshal.GetFunctionPointerForDelegate<ReleaseArrowArray>(ReleaseArray);
+ cArray->private_data = FromDisposable(allocationOwner);
+ allocationOwner = null;
+ }
+ finally
+ {
+ allocationOwner?.Dispose();
+ }
+ }
+
+ /// <summary>
+ /// Export a <see cref="RecordBatch"/> to a <see cref="CArrowArray"/>. Whether or not the
+ /// export succeeds, the original record batch becomes invalid. Clone the batch to continue using it
+ /// after a copy has been exported.
+ /// </summary>
+ /// <param name="batch">The record batch to export</param>
+ /// <param name="cArray">An allocated but uninitialized CArrowArray pointer.</param>
+ /// <example>
+ /// <code>
+ /// CArrowArray* exportPtr = CArrowArray.Create();
+ /// CArrowArrayExporter.ExportRecordBatch(batch, exportPtr);
+ /// foreign_import_function(exportPtr);
+ /// </code>
+ /// </example>
+ public static unsafe void ExportRecordBatch(RecordBatch batch, CArrowArray* cArray)
+ {
+ if (batch == null)
+ {
+ throw new ArgumentNullException(nameof(batch));
+ }
+ if (cArray == null)
+ {
+ throw new ArgumentNullException(nameof(cArray));
+ }
+ if (cArray->release != null)
+ {
+ throw new ArgumentException("Cannot export array to a struct that is already initialized.", nameof(cArray));
+ }
+
+ ExportedAllocationOwner allocationOwner = new ExportedAllocationOwner();
+ try
+ {
+ ConvertRecordBatch(allocationOwner, batch, cArray);
+ cArray->release = (delegate* unmanaged[Stdcall]<CArrowArray*, void>)Marshal.GetFunctionPointerForDelegate<ReleaseArrowArray>(ReleaseArray);
+ cArray->private_data = FromDisposable(allocationOwner);
+ allocationOwner = null;
+ }
+ finally
+ {
+ allocationOwner?.Dispose();
+ }
+ }
+
+ private unsafe static void ConvertArray(ExportedAllocationOwner sharedOwner, ArrayData array, CArrowArray* cArray)
+ {
+ cArray->length = array.Length;
+ cArray->offset = array.Offset;
+ cArray->null_count = array.NullCount;
+ cArray->release = (delegate* unmanaged[Stdcall]<CArrowArray*, void>)Marshal.GetFunctionPointerForDelegate<ReleaseArrowArray>(ReleaseArray);
+ cArray->private_data = null;
+
+ cArray->n_buffers = array.Buffers?.Length ?? 0;
+ cArray->buffers = null;
+ if (cArray->n_buffers > 0)
+ {
+ cArray->buffers = (byte**)Marshal.AllocCoTaskMem(array.Buffers.Length * IntPtr.Size);
+ for (int i = 0; i < array.Buffers.Length; i++)
+ {
+ ArrowBuffer buffer = array.Buffers[i];
+ IntPtr ptr;
+ if (!buffer.TryExport(sharedOwner, out ptr))
+ {
+ throw new NotSupportedException(); // TODO
Review Comment:
Can we address this TODO in this PR?
##########
csharp/src/Apache.Arrow/C/CArrowArrayExporter.cs:
##########
@@ -0,0 +1,210 @@
+// 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 System.Runtime.InteropServices;
+using Apache.Arrow.Memory;
+
+namespace Apache.Arrow.C
+{
+ public static class CArrowArrayExporter
+ {
+ private unsafe delegate void ReleaseArrowArray(CArrowArray* cArray);
+
+ /// <summary>
+ /// Export an <see cref="IArrowArray"/> to a <see cref="CArrowArray"/>. Whether or not the
+ /// export succeeds, the original array becomes invalid. Clone an array to continue using it
+ /// after a copy has been exported.
+ /// </summary>
+ /// <param name="array">The array to export</param>
+ /// <param name="cArray">An allocated but uninitialized CArrowArray pointer.</param>
+ /// <example>
+ /// <code>
+ /// CArrowArray* exportPtr = CArrowArray.Create();
+ /// CArrowArrayExporter.ExportArray(array, exportPtr);
+ /// foreign_import_function(exportPtr);
+ /// </code>
+ /// </example>
+ public static unsafe void ExportArray(IArrowArray array, CArrowArray* cArray)
+ {
+ if (array == null)
+ {
+ throw new ArgumentNullException(nameof(array));
+ }
+ if (cArray == null)
+ {
+ throw new ArgumentNullException(nameof(cArray));
+ }
+ if (cArray->release != null)
+ {
+ throw new ArgumentException("Cannot export array to a struct that is already initialized.", nameof(cArray));
+ }
+
+ ExportedAllocationOwner allocationOwner = new ExportedAllocationOwner();
+ try
+ {
+ ConvertArray(allocationOwner, array.Data, cArray);
+ cArray->release = (delegate* unmanaged[Stdcall]<CArrowArray*, void>)Marshal.GetFunctionPointerForDelegate<ReleaseArrowArray>(ReleaseArray);
+ cArray->private_data = FromDisposable(allocationOwner);
+ allocationOwner = null;
+ }
+ finally
+ {
+ allocationOwner?.Dispose();
+ }
+ }
+
+ /// <summary>
+ /// Export a <see cref="RecordBatch"/> to a <see cref="CArrowArray"/>. Whether or not the
+ /// export succeeds, the original record batch becomes invalid. Clone the batch to continue using it
+ /// after a copy has been exported.
+ /// </summary>
+ /// <param name="batch">The record batch to export</param>
+ /// <param name="cArray">An allocated but uninitialized CArrowArray pointer.</param>
+ /// <example>
+ /// <code>
+ /// CArrowArray* exportPtr = CArrowArray.Create();
+ /// CArrowArrayExporter.ExportRecordBatch(batch, exportPtr);
+ /// foreign_import_function(exportPtr);
+ /// </code>
+ /// </example>
+ public static unsafe void ExportRecordBatch(RecordBatch batch, CArrowArray* cArray)
+ {
+ if (batch == null)
+ {
+ throw new ArgumentNullException(nameof(batch));
+ }
+ if (cArray == null)
+ {
+ throw new ArgumentNullException(nameof(cArray));
+ }
+ if (cArray->release != null)
+ {
+ throw new ArgumentException("Cannot export array to a struct that is already initialized.", nameof(cArray));
+ }
+
+ ExportedAllocationOwner allocationOwner = new ExportedAllocationOwner();
+ try
+ {
+ ConvertRecordBatch(allocationOwner, batch, cArray);
+ cArray->release = (delegate* unmanaged[Stdcall]<CArrowArray*, void>)Marshal.GetFunctionPointerForDelegate<ReleaseArrowArray>(ReleaseArray);
+ cArray->private_data = FromDisposable(allocationOwner);
+ allocationOwner = null;
+ }
+ finally
+ {
+ allocationOwner?.Dispose();
+ }
+ }
+
+ private unsafe static void ConvertArray(ExportedAllocationOwner sharedOwner, ArrayData array, CArrowArray* cArray)
+ {
+ cArray->length = array.Length;
+ cArray->offset = array.Offset;
+ cArray->null_count = array.NullCount;
+ cArray->release = (delegate* unmanaged[Stdcall]<CArrowArray*, void>)Marshal.GetFunctionPointerForDelegate<ReleaseArrowArray>(ReleaseArray);
+ cArray->private_data = null;
+
+ cArray->n_buffers = array.Buffers?.Length ?? 0;
+ cArray->buffers = null;
+ if (cArray->n_buffers > 0)
+ {
+ cArray->buffers = (byte**)Marshal.AllocCoTaskMem(array.Buffers.Length * IntPtr.Size);
+ for (int i = 0; i < array.Buffers.Length; i++)
+ {
+ ArrowBuffer buffer = array.Buffers[i];
+ IntPtr ptr;
+ if (!buffer.TryExport(sharedOwner, out ptr))
+ {
+ throw new NotSupportedException(); // TODO
+ }
+ cArray->buffers[i] = (byte*)ptr;
+ }
+ }
+
+ cArray->n_children = array.Children?.Length ?? 0;
+ cArray->children = null;
+ if (cArray->n_children > 0)
+ {
+ cArray->children = (CArrowArray**)Marshal.AllocCoTaskMem(IntPtr.Size * array.Children.Length);
+ for (int i = 0; i < array.Children.Length; i++)
+ {
+ cArray->children[i] = CArrowArray.Create();
+ ConvertArray(sharedOwner, array.Children[i], cArray->children[i]);
+ }
+ }
+
+ cArray->dictionary = null;
+ if (array.Dictionary != null)
+ {
+ cArray->dictionary = CArrowArray.Create();
+ ConvertArray(sharedOwner, array.Dictionary, cArray->dictionary);
+ }
+ }
+
+ private unsafe static void ConvertRecordBatch(ExportedAllocationOwner sharedOwner, RecordBatch batch, CArrowArray* cArray)
+ {
+ cArray->length = batch.Length;
+ cArray->offset = 0;
+ cArray->null_count = 0;
+ cArray->release = (delegate* unmanaged[Stdcall]<CArrowArray*, void>)Marshal.GetFunctionPointerForDelegate<ReleaseArrowArray>(ReleaseArray);
+ cArray->private_data = null;
+
+ cArray->n_buffers = 1;
+ cArray->buffers = (byte**)Marshal.AllocCoTaskMem(IntPtr.Size);
Review Comment:
Why are we using `AllocCoTaskMem` here and in other places?
##########
csharp/src/Apache.Arrow/Memory/NativeMemoryManager.cs:
##########
@@ -15,24 +15,32 @@
using System;
using System.Buffers;
-using System.Diagnostics;
using System.Runtime.CompilerServices;
-using System.Runtime.InteropServices;
using System.Threading;
namespace Apache.Arrow.Memory
{
- public class NativeMemoryManager: MemoryManager<byte>
+ public class NativeMemoryManager : MemoryManager<byte>, IOwnableAllocation
{
private IntPtr _ptr;
private readonly int _offset;
private readonly int _length;
+ private readonly INativeAllocationOwner _owner;
public NativeMemoryManager(IntPtr ptr, int offset, int length)
{
_ptr = ptr;
_offset = offset;
_length = length;
+ _owner = NativeMemoryAllocator.ExclusiveOwner;
+ }
Review Comment:
```suggestion
public NativeMemoryManager(IntPtr ptr, int offset, int length)
: this(NativeMemoryAllocator.ExclusiveOwner, ptr, offset, length)
{
}
```
##########
csharp/src/Apache.Arrow/C/CArrowArrayExporter.cs:
##########
@@ -0,0 +1,210 @@
+// 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 System.Runtime.InteropServices;
+using Apache.Arrow.Memory;
+
+namespace Apache.Arrow.C
+{
+ public static class CArrowArrayExporter
+ {
+ private unsafe delegate void ReleaseArrowArray(CArrowArray* cArray);
+
+ /// <summary>
+ /// Export an <see cref="IArrowArray"/> to a <see cref="CArrowArray"/>. Whether or not the
+ /// export succeeds, the original array becomes invalid. Clone an array to continue using it
+ /// after a copy has been exported.
+ /// </summary>
+ /// <param name="array">The array to export</param>
+ /// <param name="cArray">An allocated but uninitialized CArrowArray pointer.</param>
+ /// <example>
+ /// <code>
+ /// CArrowArray* exportPtr = CArrowArray.Create();
+ /// CArrowArrayExporter.ExportArray(array, exportPtr);
+ /// foreign_import_function(exportPtr);
+ /// </code>
+ /// </example>
+ public static unsafe void ExportArray(IArrowArray array, CArrowArray* cArray)
+ {
+ if (array == null)
+ {
+ throw new ArgumentNullException(nameof(array));
+ }
+ if (cArray == null)
+ {
+ throw new ArgumentNullException(nameof(cArray));
+ }
+ if (cArray->release != null)
+ {
+ throw new ArgumentException("Cannot export array to a struct that is already initialized.", nameof(cArray));
+ }
+
+ ExportedAllocationOwner allocationOwner = new ExportedAllocationOwner();
+ try
+ {
+ ConvertArray(allocationOwner, array.Data, cArray);
+ cArray->release = (delegate* unmanaged[Stdcall]<CArrowArray*, void>)Marshal.GetFunctionPointerForDelegate<ReleaseArrowArray>(ReleaseArray);
Review Comment:
This applies for all the function pointers we need to set on these structs.
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