Internalize IDataSaver interface (#2329)

Author: Ivanidzo4ka

src/Microsoft.ML.Data/Commands/SaveDataCommand.cs

@@ -182,7 +182,8 @@ private void RunCore(IChannel ch)
         }
     }
 
-    public static class DataSaverUtils
+    [BestFriend]
+    internal static class DataSaverUtils
     {
         public static void SaveDataView(IChannel ch, IDataSaver saver, IDataView view, IFileHandle file, bool keepHidden = false)
         {

src/Microsoft.ML.Data/Data/IDataLoader.cs

@@ -55,9 +55,11 @@ public interface IDataLoader : IDataView, ICanSaveModel
     {
     }
 
-    public delegate void SignatureDataSaver();
+    [BestFriend]
+    internal delegate void SignatureDataSaver();
 
-    public interface IDataSaver
+    [BestFriend]
+    internal interface IDataSaver
     {
         /// <summary>
         /// Check if the column can be saved.

src/Microsoft.ML.Data/DataLoadSave/Binary/BinarySaver.cs

@@ -10,7 +10,6 @@
 using System.Reflection;
 using System.Runtime.InteropServices;
 using System.Text;
-using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.Data.DataView;
 using Microsoft.ML;
@@ -26,7 +25,8 @@ namespace Microsoft.ML.Data.IO
 {
     using Stopwatch = System.Diagnostics.Stopwatch;
 
-    public sealed class BinarySaver : IDataSaver
+    [BestFriend]
+    internal sealed class BinarySaver : IDataSaver
     {
         public sealed class Arguments
         {

src/Microsoft.ML.Data/DataLoadSave/Text/TextSaver.cs

@@ -19,7 +19,8 @@
 
 namespace Microsoft.ML.Data.IO
 {
-    public sealed class TextSaver : IDataSaver
+    [BestFriend]
+    internal sealed class TextSaver : IDataSaver
     {
         // REVIEW: consider saving a command line in a separate file.
         public sealed class Arguments

src/Microsoft.ML.Data/DataLoadSave/Transpose/TransposeSaver.cs

@@ -24,7 +24,8 @@ namespace Microsoft.ML.Data.IO
     /// Saver for a format that can be loaded using the <see cref="TransposeLoader"/>.
     /// </summary>
     /// <seealso cref="TransposeLoader"/>
-    public sealed class TransposeSaver : IDataSaver
+    [BestFriend]
+    internal sealed class TransposeSaver : IDataSaver
     {
         public sealed class Arguments
         {

src/Microsoft.ML.Data/Utilities/ComponentCreation.cs

@@ -148,7 +148,7 @@ public static IDataLoader CreateLoader(this IHostEnvironment env, string setting
         /// <summary>
         /// Creates a data saver from the arguments object.
         /// </summary>
-        public static IDataSaver CreateSaver<TArgs>(this IHostEnvironment env, TArgs arguments)
+        internal static IDataSaver CreateSaver<TArgs>(this IHostEnvironment env, TArgs arguments)
             where TArgs : class, new()
         {
             Contracts.CheckValue(env, nameof(env));
@@ -158,7 +158,7 @@ public static IDataSaver CreateSaver<TArgs>(this IHostEnvironment env, TArgs arg
         /// <summary>
         /// Creates a data saver from the 'LoadName{settings}' string.
         /// </summary>
-        public static IDataSaver CreateSaver(this IHostEnvironment env, string settings)
+        internal static IDataSaver CreateSaver(this IHostEnvironment env, string settings)
         {
             Contracts.CheckValue(env, nameof(env));
             return CreateCore<IDataSaver>(env, typeof(SignatureDataSaver), settings);