adamreeve commented on code in PR #100:
URL: https://github.com/apache/arrow-dotnet/pull/100#discussion_r2404804004
##########
src/Apache.Arrow.Flight/Internal/SchemaWriter.cs:
##########
@@ -13,53 +13,28 @@
// See the License for the specific language governing permissions and
// limitations under the License.
-using System;
-using System.Collections.Generic;
-using System.IO;
-using System.Text;
-using System.Threading;
-using System.Threading.Tasks;
-using Apache.Arrow.Flatbuf;
-using Apache.Arrow.Flight.Internal;
-using Apache.Arrow.Ipc;
+using Apache.Arrow.Flight;
using Google.Protobuf;
-namespace Apache.Arrow.Flight.Internal
+namespace Apache.Arrow.Flight
{
- /// <summary>
- /// This class handles writing schemas
- /// </summary>
- internal class SchemaWriter : ArrowStreamWriter
+ internal static class SchemaWriter
{
- internal SchemaWriter(Stream baseStream, Schema schema) :
base(baseStream, schema)
+ public static ByteString ToByteString(Schema schema)
{
- }
-
- public void WriteSchema(Schema schema, CancellationToken
cancellationToken)
- {
- var offset = base.SerializeSchema(schema);
- WriteMessage(MessageHeader.Schema, offset, 0);
- }
-
- public static ByteString SerializeSchema(Schema schema,
CancellationToken cancellationToken = default(CancellationToken))
- {
- using (var memoryStream = new MemoryStream())
- {
- var writer = new SchemaWriter(memoryStream, schema);
- writer.WriteSchema(schema, cancellationToken);
-
- memoryStream.Position = 0;
- return ByteString.FromStream(memoryStream);
- }
+ return schema == null ?
+ ByteString.Empty :
+
UnsafeByteOperations.UnsafeWrap(ArrowSerializationHelpers.SerializeSchema(schema));
}
}
}
public static class SchemaExtension
{
- // Translate an Apache.Arrow.Schema to FlatBuffer Schema to ByteString
+ // This should never have been a public class without a namespace
+ // TODO: Mark as obsolete once sufficient time has passed
Review Comment:
Should we just mark this as obsolete now? Otherwise there's no indication
that users should switch to something else. Either way, it would be good to add
a comment to direct users to use `ArrowSerializationHelpers.SerializeSchema`
instead if we don't want people using this.
##########
src/Apache.Arrow/ArrowSerializationHelpers.cs:
##########
@@ -0,0 +1,88 @@
+// 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.IO;
+using Apache.Arrow.Flatbuf;
+using Apache.Arrow.Ipc;
+
+namespace Apache.Arrow
+{
+ /// <summary>
+ /// Helpers for serializing partial Arrow structures to and from buffers.
+ /// </summary>
+ public static class ArrowSerializationHelpers
+ {
+ public static Schema DeserializeSchema(ReadOnlyMemory<byte>
serializedSchema)
+ {
+ ArrowMemoryReaderImplementation implementation = new
ArrowMemoryReaderImplementation(serializedSchema, null);
+ return implementation.Schema;
+ }
+
+ public static RecordBatch DeserializeRecordBatch(Schema schema,
ReadOnlyMemory<byte> serializedRecordBatch)
+ {
+ ArrowMemoryReaderImplementation implementation = new
ArrowMemoryReaderImplementation(schema, serializedRecordBatch, null);
+ return implementation.ReadNextRecordBatch();
+ }
+
+ public static byte[] SerializeSchema(Schema schema)
+ {
+ using (var stream = new MemoryStream())
+ {
+ var writer = new SchemaWriter(stream, schema);
+ writer.WriteSchema(schema);
+ return stream.ToArray();
+ }
+ }
+
+ public static byte[] SerializeRecordBatch(RecordBatch recordBatch)
+ {
+ using (var stream = new MemoryStream())
+ {
+ var writer = new SchemaWriter(stream, recordBatch.Schema);
+ writer.WriteBatch(recordBatch);
+ return stream.ToArray();
+ }
+ }
+
+ /// <summary>
+ /// This class handles writing schemas
Review Comment:
It also writes RecordBatches. I can't think of a better name for it though.
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