feat(csharp/src/Apache.Arrow.Adbc): Cleanup use of List<T> in APIs an…

…d implementation (apache#1761)

Replaces the use of `List<T>` in most API signatures with
`IReadOnlyList<T>` to allow many different types of collections (such as
arrays) to be passed in.

Replaces the use of `List<T>` in many implementations with `T[]` for
performance and readability benefits.

Closes apache#1757

csharp/src/Apache.Arrow.Adbc/AdbcConnection.cs

@@ -73,7 +73,7 @@ public virtual void Dispose()
         /// Metadata about the driver and/or database
         /// </returns>
         /// <exception cref="ArgumentNullException"></exception>
-        public virtual IArrowArrayStream GetInfo(List<AdbcInfoCode> codes)
+        public virtual IArrowArrayStream GetInfo(IReadOnlyList<AdbcInfoCode> codes)
         {
             if (codes == null)
                 throw new ArgumentNullException(nameof(codes));
@@ -119,7 +119,7 @@ public abstract IArrowArrayStream GetObjects(
             string catalogPattern,
             string dbSchemaPattern,
             string tableNamePattern,
-            List<string> tableTypes,
+            IReadOnlyList<string> tableTypes,
             string columnNamePattern);
 
         public enum GetObjectsDepth

csharp/src/Apache.Arrow.Adbc/C/CAdbcDriverExporter.cs

@@ -22,7 +22,6 @@
 using Apache.Arrow.C;
 using Apache.Arrow.Ipc;
 
-
 #if NETSTANDARD
 using Apache.Arrow.Adbc.Extensions;
 #endif
@@ -775,7 +774,7 @@ public unsafe void GetObjects(ref CAdbcConnection nativeConnection, int depth, b
                 columnNamePattern = Marshal.PtrToStringUTF8((IntPtr)column_name);
 #endif
 
-                List<string> tableTypes = null;
+                string[] tableTypes = null;
                 const int maxTableTypeCount = 100;
                 if (table_type != null)
                 {
@@ -790,13 +789,13 @@ public unsafe void GetObjects(ref CAdbcConnection nativeConnection, int depth, b
                         throw new InvalidOperationException($"We do not expect to get more than {maxTableTypeCount} table types");
                     }
 
-                    tableTypes = new List<string>(count);
+                    tableTypes = new string[count];
                     for (int i = 0; i < count; i++)
                     {
 #if NETSTANDARD
-                        tableTypes.Add(MarshalExtensions.PtrToStringUTF8((IntPtr)table_type[i]));
+                        tableTypes[i] = MarshalExtensions.PtrToStringUTF8((IntPtr)table_type[i]);
 #else
-                        tableTypes.Add(Marshal.PtrToStringUTF8((IntPtr)table_type[i]));
+                        tableTypes[i] = Marshal.PtrToStringUTF8((IntPtr)table_type[i]);
 #endif
                     }
                 }

csharp/src/Apache.Arrow.Adbc/C/CAdbcDriverImporter.cs

@@ -20,12 +20,10 @@
 using System.IO;
 using System.Linq;
 using System.Runtime.InteropServices;
+using Apache.Arrow.Adbc.Extensions;
 using Apache.Arrow.C;
 using Apache.Arrow.Ipc;
 
-#if NETSTANDARD
-using Apache.Arrow.Adbc.Extensions;
-#endif
 
 namespace Apache.Arrow.Adbc.C
 {
@@ -222,7 +220,7 @@ public unsafe override AdbcStatement CreateStatement()
                 return new AdbcStatementNative(_nativeDriver, nativeStatement);
             }
 
-            public unsafe override IArrowArrayStream GetInfo(List<AdbcInfoCode> codes)
+            public unsafe override IArrowArrayStream GetInfo(IReadOnlyList<AdbcInfoCode> codes)
             {
                 CArrowArrayStream* nativeArrayStream = CArrowArrayStream.Create();
 
@@ -236,7 +234,7 @@ public unsafe override IArrowArrayStream GetInfo(List<AdbcInfoCode> codes)
                 return arrowArrayStream;
             }
 
-            public override unsafe IArrowArrayStream GetObjects(GetObjectsDepth depth, string catalogPattern, string dbSchemaPattern, string tableNamePattern, List<string> tableTypes, string columnNamePattern)
+            public override unsafe IArrowArrayStream GetObjects(GetObjectsDepth depth, string catalogPattern, string dbSchemaPattern, string tableNamePattern, IReadOnlyList<string> tableTypes, string columnNamePattern)
             {
                 CArrowArrayStream* nativeArrayStream = CArrowArrayStream.Create();
 
@@ -691,20 +689,20 @@ public unsafe void Dispose()
             }
 
 #if NET5_0_OR_GREATER
-            public unsafe void Call(delegate* unmanaged<CAdbcConnection*, int*, int, CArrowArrayStream*, CAdbcError*, AdbcStatusCode> fn, ref CAdbcConnection connection, List<AdbcInfoCode> infoCodes, CArrowArrayStream* stream)
+            public unsafe void Call(delegate* unmanaged<CAdbcConnection*, int*, int, CArrowArrayStream*, CAdbcError*, AdbcStatusCode> fn, ref CAdbcConnection connection, IReadOnlyList<AdbcInfoCode> infoCodes, CArrowArrayStream* stream)
             {
                 fixed (CAdbcConnection* cn = &connection)
                 fixed (CAdbcError* e = &_error)
                 {
-                    Span<AdbcInfoCode> span = CollectionsMarshal.AsSpan(infoCodes);
+                    Span<AdbcInfoCode> span = infoCodes.AsSpan();
                     fixed (AdbcInfoCode* spanPtr = span)
                     {
                         TranslateCode(fn(cn, (int*)spanPtr, infoCodes.Count, stream, e));
                     }
                 }
             }
 #else
-            public unsafe void Call(IntPtr ptr, ref CAdbcConnection connection, List<AdbcInfoCode> infoCodes, CArrowArrayStream* stream)
+            public unsafe void Call(IntPtr ptr, ref CAdbcConnection connection, IReadOnlyList<AdbcInfoCode> infoCodes, CArrowArrayStream* stream)
             {
                 fixed (CAdbcConnection* cn = &connection)
                 fixed (CAdbcError* e = &_error)
@@ -719,16 +717,16 @@ public unsafe void Call(IntPtr ptr, ref CAdbcConnection connection, List<AdbcInf
 #endif
 
 #if NET5_0_OR_GREATER
-            public unsafe void Call(delegate* unmanaged<CAdbcConnection*, int, byte*, byte*, byte*, byte**, byte*, CArrowArrayStream*, CAdbcError*, AdbcStatusCode> fn, ref CAdbcConnection connection, int depth, string catalog, string db_schema, string table_name, List<string> table_types, string column_name, CArrowArrayStream* stream)
+            public unsafe void Call(delegate* unmanaged<CAdbcConnection*, int, byte*, byte*, byte*, byte**, byte*, CArrowArrayStream*, CAdbcError*, AdbcStatusCode> fn, ref CAdbcConnection connection, int depth, string catalog, string db_schema, string table_name, IReadOnlyList<string> table_types, string column_name, CArrowArrayStream* stream)
 #else
-            public unsafe void Call(IntPtr fn, ref CAdbcConnection connection, int depth, string catalog, string db_schema, string table_name, List<string> table_types, string column_name, CArrowArrayStream* stream)
+            public unsafe void Call(IntPtr fn, ref CAdbcConnection connection, int depth, string catalog, string db_schema, string table_name, IReadOnlyList<string> table_types, string column_name, CArrowArrayStream* stream)
 #endif
             {
                 byte* bcatalog, bDb_schema, bTable_name, bColumn_Name;
 
                 if (table_types == null)
                 {
-                    table_types = new List<string>();
+                    table_types = new string[0];
                 }
 
                 // need to terminate with a null entry per https://github.com/apache/arrow-adbc/blob/b97e22c4d6524b60bf261e1970155500645be510/adbc.h#L909-L911

csharp/src/Apache.Arrow.Adbc/Extensions/CollectionExtensions.cs

@@ -0,0 +1,43 @@
+/*
+ * 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.Linq;
+
+#if NET5_0_OR_GREATER
+using System.Runtime.InteropServices;
+#endif
+
+namespace Apache.Arrow.Adbc.Extensions
+{
+    internal static class CollectionExtensions
+    {
+        public static Span<T> AsSpan<T>(this IReadOnlyList<T> list)
+        {
+            T[] array = list as T[];
+            if (array != null) { return array.AsSpan(); }
+
+#if NET5_0_OR_GREATER
+            List<T> concreteList = list as List<T>;
+            if (concreteList != null) { return CollectionsMarshal.AsSpan(concreteList); }
+#endif
+
+            return list.ToArray().AsSpan();
+        }
+    }
+}

csharp/src/Apache.Arrow.Adbc/Results.cs

@@ -76,9 +76,9 @@ public sealed class PartitionedResult
     {
         private readonly Schema _schema;
         private readonly long _affectedRows = -1;
-        private readonly List<PartitionDescriptor> _partitionDescriptors;
+        private readonly IReadOnlyList<PartitionDescriptor> _partitionDescriptors;
 
-        public PartitionedResult(Schema schema, long affectedRows, List<PartitionDescriptor> partitionDescriptors)
+        public PartitionedResult(Schema schema, long affectedRows, IReadOnlyList<PartitionDescriptor> partitionDescriptors)
         {
             _schema = schema;
             _affectedRows = affectedRows;
@@ -98,6 +98,6 @@ public PartitionedResult(Schema schema, long affectedRows, List<PartitionDescrip
         /// <summary>
         /// Get partitions.
         /// </summary>
-        public List<PartitionDescriptor> PartitionDescriptors { get => _partitionDescriptors; }
+        public IReadOnlyList<PartitionDescriptor> PartitionDescriptors { get => _partitionDescriptors; }
     }
 }

csharp/src/Apache.Arrow.Adbc/StandardSchemas.cs

@@ -15,7 +15,6 @@
  * limitations under the License.
  */
 
-using System;
 using System.Collections.Generic;
 using System.Linq;
 using Apache.Arrow.Types;
@@ -33,13 +32,13 @@ public static class StandardSchemas
         /// </summary>
         public static readonly Schema GetInfoSchema =
             new Schema(
-                new List<Field>()
+                new Field[]
                 {
                     new Field("info_name", UInt32Type.Default, false),
                     new Field(
                         "info_value",
                         new UnionType(
-                            new List<Field>()
+                            new Field[]
                             {
                                 new Field("string_value", StringType.Default, true),
                                 new Field("bool_value", BooleanType.Default, true),
@@ -56,7 +55,7 @@ public static class StandardSchemas
                                     "int32_to_int32_list_map",
                                     new ListType(
                                         new Field("entries", new StructType(
-                                            new List<Field>()
+                                            new Field[]
                                             {
                                                 new Field("key", Int32Type.Default, false),
                                                 new Field("value", Int32Type.Default, true),
@@ -75,22 +74,22 @@ public static class StandardSchemas
         );
 
         public static readonly Schema TableTypesSchema = new Schema(
-            new List<Field>()
+            new Field[]
             {
                 new Field("table_type", StringType.Default, false)
             },
             metadata: null
         );
 
-        public static readonly List<Field> UsageSchema = new List<Field>()
+        public static readonly IReadOnlyList<Field> UsageSchema = new Field[]
         {
             new Field("fk_catalog", StringType.Default, true),
             new Field("fk_db_schema", StringType.Default, true),
             new Field("fk_table", StringType.Default, false),
             new Field("fk_column_name", StringType.Default, false)
         };
 
-        public static readonly List<Field> ConstraintSchema = new List<Field>()
+        public static readonly IReadOnlyList<Field> ConstraintSchema = new Field[]
         {
             new Field("constraint_name", StringType.Default, false),
             new Field("constraint_type", StringType.Default, false),
@@ -108,8 +107,8 @@ public static class StandardSchemas
             ),
         };
 
-        public static readonly List<Field> ColumnSchema =
-            new List<Field>()
+        public static readonly IReadOnlyList<Field> ColumnSchema =
+            new Field[]
             {
                 new Field("column_name", StringType.Default, false),
                 new Field("ordinal_position", Int32Type.Default, true),
@@ -132,7 +131,7 @@ public static class StandardSchemas
                 new Field("xdbc_is_generatedcolumn", StringType.Default, true)
             };
 
-        public static readonly List<Field> TableSchema = new List<Field>() {
+        public static readonly IReadOnlyList<Field> TableSchema = new Field[] {
           new Field("table_name", StringType.Default, false, null),
           new Field("table_type", StringType.Default, false, null),
           new Field(
@@ -151,7 +150,7 @@ public static class StandardSchemas
           )
         };
 
-        public static readonly List<Field> DbSchemaSchema = new List<Field>()
+        public static readonly IReadOnlyList<Field> DbSchemaSchema = new Field[]
         {
             new Field("db_schema_name", StringType.Default, false, null),
             new Field(
@@ -164,7 +163,7 @@ public static class StandardSchemas
         };
 
         public static readonly Schema GetObjectsSchema = new Schema(
-            new List<Field>()
+            new Field[]
             {
                 new Field("catalog_name", StringType.Default, false),
                 new Field(

csharp/src/Drivers/Apache/Hive2/HiveServer2Connection.cs

@@ -59,7 +59,7 @@ public void Open()
         protected abstract TProtocol CreateProtocol();
         protected abstract TOpenSessionReq CreateSessionRequest();
 
-        public override IArrowArrayStream GetObjects(GetObjectsDepth depth, string catalogPattern, string dbSchemaPattern, string tableNamePattern, List<string> tableTypes, string columnNamePattern)
+        public override IArrowArrayStream GetObjects(GetObjectsDepth depth, string catalogPattern, string dbSchemaPattern, string tableNamePattern, IReadOnlyList<string> tableTypes, string columnNamePattern)
         {
             throw new NotImplementedException();
         }

csharp/src/Drivers/Apache/Impala/ImpalaConnection.cs

@@ -60,7 +60,7 @@ public override AdbcStatement CreateStatement()
             return new ImpalaStatement(this);
         }
 
-        public override IArrowArrayStream GetObjects(GetObjectsDepth depth, string catalogPattern, string dbSchemaPattern, string tableNamePattern, List<string> tableTypes, string columnNamePattern)
+        public override IArrowArrayStream GetObjects(GetObjectsDepth depth, string catalogPattern, string dbSchemaPattern, string tableNamePattern, IReadOnlyList<string> tableTypes, string columnNamePattern)
         {
             throw new System.NotImplementedException();
         }