ITransformer derives from ICanSaveModel and explicit implementation for ICanSaveModel (#2431)

Author: artidoro

src/Microsoft.ML.Core/Data/IEstimator.cs

@@ -7,6 +7,7 @@
 using System.Linq;
 using Microsoft.Data.DataView;
 using Microsoft.ML.Data;
+using Microsoft.ML.Model;
 
 namespace Microsoft.ML.Core.Data
 {
@@ -263,7 +264,7 @@ public interface IDataReaderEstimator<in TSource, out TReader>
     /// The transformer is a component that transforms data.
     /// It also supports 'schema propagation' to answer the question of 'how will the data with this schema look, after you transform it?'.
     /// </summary>
-    public interface ITransformer
+    public interface ITransformer : ICanSaveModel
     {
         /// <summary>
         /// Schema propagation for transformers.

src/Microsoft.ML.Data/Model/ModelHeader.cs renamed to src/Microsoft.ML.Core/Data/ModelHeader.cs

@@ -10,7 +10,8 @@
 
 namespace Microsoft.ML.Model
 {
-    [StructLayout(LayoutKind.Explicit, Size = ModelHeader.Size)]
+    [BestFriend]
+    [StructLayout(LayoutKind.Explicit, Size = Size)]
     internal struct ModelHeader
     {
         /// <summary>

src/Microsoft.ML.Data/Model/ModelLoadContext.cs renamed to src/Microsoft.ML.Core/Data/ModelLoadContext.cs

@@ -10,6 +10,12 @@
 
 namespace Microsoft.ML.Model
 {
+    /// <summary>
+    /// Signature for a repository based model loader. This is the dual of <see cref="ICanSaveModel"/>.
+    /// </summary>
+    [BestFriend]
+    internal delegate void SignatureLoadModel(ModelLoadContext ctx);
+
     public sealed partial class ModelLoadContext : IDisposable
     {
         public const string ModelStreamName = "Model.key";

src/Microsoft.ML.Data/Model/ModelLoading.cs renamed to src/Microsoft.ML.Core/Data/ModelLoading.cs

@@ -10,13 +10,11 @@
 
 namespace Microsoft.ML.Model
 {
-    /// <summary>
-    /// Signature for a repository based model loader. This is the dual of ICanSaveModel.
-    /// </summary>
-    public delegate void SignatureLoadModel(ModelLoadContext ctx);
-
     /// <summary>
     /// For saving a model into a repository.
+    /// Classes implementing <see cref="ICanSaveModel"/> should do an explicit implementation of <see cref="Save(ModelSaveContext)"/>.
+    /// Classes inheriting <see cref="ICanSaveModel"/> from a base class should overwrite the function invoked by <see cref="Save(ModelSaveContext)"/>
+    /// in that base class, if there is one.
     /// </summary>
     public interface ICanSaveModel
     {
@@ -293,6 +291,8 @@ protected Entry AddEntry(string pathEnt, Stream stream)
 
     public sealed class RepositoryWriter : Repository
     {
+        private const string DirTrainingInfo = "TrainingInfo";
+
         private ZipArchive _archive;
         private Queue<KeyValuePair<string, Stream>> _closed;
 
@@ -301,7 +301,7 @@ public static RepositoryWriter CreateNew(Stream stream, IExceptionContext ectx =
             Contracts.CheckValueOrNull(ectx);
             ectx.CheckValue(stream, nameof(stream));
             var rep = new RepositoryWriter(stream, ectx, useFileSystem);
-            using (var ent = rep.CreateEntry(ModelFileUtils.DirTrainingInfo, "Version.txt"))
+            using (var ent = rep.CreateEntry(DirTrainingInfo, "Version.txt"))
             using (var writer = Utils.OpenWriter(ent.Stream))
                 writer.WriteLine(typeof(RepositoryWriter).Assembly.GetName().Version);
             return rep;

src/Microsoft.ML.Data/Model/ModelSaveContext.cs renamed to src/Microsoft.ML.Core/Data/ModelSaveContext.cs

@@ -942,7 +942,7 @@ private static Stream OpenStream(string filename)
             return OpenStream(files);
         }
 
-        public void Save(ModelSaveContext ctx)
+        void ICanSaveModel.Save(ModelSaveContext ctx)
         {
             _host.CheckValue(ctx, nameof(ctx));
             ctx.CheckAtModel();

src/Microsoft.ML.Data/Model/ModelSaving.cs renamed to src/Microsoft.ML.Core/Data/ModelSaving.cs

@@ -502,7 +502,7 @@ private static IDataLoader LoadTransforms(ModelLoadContext ctx, IDataLoader srcL
                 });
         }
 
-        public void Save(ModelSaveContext ctx)
+        void ICanSaveModel.Save(ModelSaveContext ctx)
         {
             _host.CheckValue(ctx, nameof(ctx));
             ctx.CheckAtModel();

src/Microsoft.ML.Data/Model/Repository.cs renamed to src/Microsoft.ML.Core/Data/Repository.cs

@@ -834,7 +834,7 @@ public Bindings(ModelLoadContext ctx, TextLoader parent)
                 OutputSchema = ComputeOutputSchema();
             }
 
-            public void Save(ModelSaveContext ctx)
+            internal void Save(ModelSaveContext ctx)
             {
                 Contracts.AssertValue(ctx);
 
@@ -1283,7 +1283,7 @@ internal static IDataLoader Create(IHostEnvironment env, Arguments args, IMultiS
         internal static IDataView ReadFile(IHostEnvironment env, Arguments args, IMultiStreamSource fileSource)
             => new TextLoader(env, args, fileSource).Read(fileSource);
 
-        public void Save(ModelSaveContext ctx)
+        void ICanSaveModel.Save(ModelSaveContext ctx)
         {
             _host.CheckValue(ctx, nameof(ctx));
             ctx.CheckAtModel();
@@ -1420,7 +1420,7 @@ public RowCursor[] GetRowCursorSet(IEnumerable<Schema.Column> columnsNeeded, int
                 return Cursor.CreateSet(_reader, _files, active, n);
             }
 
-            public void Save(ModelSaveContext ctx) => _reader.Save(ctx);
+            void ICanSaveModel.Save(ModelSaveContext ctx) => ((ICanSaveModel)_reader).Save(ctx);
         }
     }
 }