Internalize much of the channel and message infrastructure

Author: TomFinley

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

@@ -190,7 +190,8 @@ public readonly struct ChannelMessage
         /// </summary>
         public string Message => _args != null ? string.Format(_message, _args) : _message;
 
-        public ChannelMessage(ChannelMessageKind kind, MessageSensitivity sensitivity, string message)
+        [BestFriend]
+        internal ChannelMessage(ChannelMessageKind kind, MessageSensitivity sensitivity, string message)
         {
             Contracts.CheckNonEmpty(message, nameof(message));
             Kind = kind;
@@ -199,7 +200,8 @@ public ChannelMessage(ChannelMessageKind kind, MessageSensitivity sensitivity, s
             _args = null;
         }
 
-        public ChannelMessage(ChannelMessageKind kind, MessageSensitivity sensitivity, string fmt, params object[] args)
+        [BestFriend]
+        internal ChannelMessage(ChannelMessageKind kind, MessageSensitivity sensitivity, string fmt, params object[] args)
         {
             Contracts.CheckNonEmpty(fmt, nameof(fmt));
             Contracts.CheckNonEmpty(args, nameof(args));

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

@@ -14,7 +14,8 @@ namespace Microsoft.ML.Runtime.Data
     /// <summary>
     /// The progress reporting classes used by <see cref="HostEnvironmentBase{THostEnvironmentBase}"/> descendants.
     /// </summary>
-    public static class ProgressReporting
+    [BestFriend]
+    internal static class ProgressReporting
     {
         /// <summary>
         /// The progress channel for <see cref="ConsoleEnvironment"/>.

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

@@ -19,6 +19,7 @@ namespace Microsoft.ML.Runtime
     /// delegates will be published in some fashion, with the target scenario being
     /// that the library will publish some sort of restful API.
     /// </summary>
+    [BestFriend]
     public sealed class ServerChannel : ServerChannel.IPendingBundleNotification, IDisposable
     {
         // See ServerChannel.md for a more elaborate discussion of high level usage and design.
@@ -250,7 +251,8 @@ public void AddDoneAction(Action onDone)
         }
     }
 
-    public static class ServerChannelUtilities
+    [BestFriend]
+    internal static class ServerChannelUtilities
     {
         /// <summary>
         /// Convenience method for <see cref="ServerChannel.Start"/> that looks more idiomatic to typical

src/Microsoft.ML.Core/Environment/HostEnvironmentBase.cs

@@ -15,7 +15,8 @@ namespace Microsoft.ML.Runtime.Data
     /// Base class for channel providers. This is a common base class for<see cref="HostEnvironmentBase{THostEnvironmentBase}"/>.
     /// The ParentFullName, ShortName, and FullName may be null or empty.
     /// </summary>
-    public abstract class ChannelProviderBase : IExceptionContext
+    [BestFriend]
+    internal abstract class ChannelProviderBase : IExceptionContext
     {
         /// <summary>
         /// Data keys that are attached to the exception thrown via the exception context.
@@ -79,43 +80,22 @@ public virtual TException Process<TException>(TException ex)
     /// <summary>
     /// Message source (a channel) that generated the message being dispatched.
     /// </summary>
-    public interface IMessageSource
+    [BestFriend]
+    internal interface IMessageSource
     {
         string ShortName { get; }
         string FullName { get; }
         bool Verbose { get; }
     }
 
-    /// <summary>
-    /// A <see cref="IHostEnvironment"/> that is also a channel listener can attach
-    /// listeners for messages, as sent through <see cref="IChannelProvider.StartPipe{TMessage}"/>.
-    /// </summary>
-    public interface IMessageDispatcher : IHostEnvironment
-    {
-        /// <summary>
-        /// Listen on this environment to messages of a particular type.
-        /// </summary>
-        /// <typeparam name="TMessage">The message type</typeparam>
-        /// <param name="listenerFunc">The action to perform when a message of the
-        /// appropriate type is received.</param>
-        void AddListener<TMessage>(Action<IMessageSource, TMessage> listenerFunc);
-
-        /// <summary>
-        /// Removes a previously added listener.
-        /// </summary>
-        /// <typeparam name="TMessage">The message type</typeparam>
-        /// <param name="listenerFunc">The previous listener function that is now being removed.</param>
-        void RemoveListener<TMessage>(Action<IMessageSource, TMessage> listenerFunc);
-    }
-
     /// <summary>
     /// A basic host environment suited for many environments.
     /// This also supports modifying the concurrency factor, provides the ability to subscribe to pipes via the
     /// AddListener/RemoveListener methods, and exposes the <see cref="ProgressReporting.ProgressTracker"/> to
     /// query progress.
     /// </summary>
     [BestFriend]
-    internal abstract class HostEnvironmentBase<TEnv> : ChannelProviderBase, IHostEnvironment, IDisposable, IChannelProvider, IMessageDispatcher
+    internal abstract class HostEnvironmentBase<TEnv> : ChannelProviderBase, IHostEnvironment, IDisposable, IChannelProvider
         where TEnv : HostEnvironmentBase<TEnv>
     {
         /// <summary>

src/Microsoft.ML.Core/Environment/TelemetryMessage.cs

@@ -13,7 +13,8 @@ namespace Microsoft.ML.Runtime
     /// <summary>
     /// A telemetry message.
     /// </summary>
-    public abstract class TelemetryMessage
+    [BestFriend]
+    internal abstract class TelemetryMessage
     {
         public static TelemetryMessage CreateCommand(string commandName, string commandText)
         {
@@ -40,7 +41,8 @@ public static TelemetryMessage CreateException(Exception exception)
     /// <summary>
     /// Message with one long text and bunch of small properties (limit on value is ~1020 chars)
     /// </summary>
-    public sealed class TelemetryTrace : TelemetryMessage
+    [BestFriend]
+    internal sealed class TelemetryTrace : TelemetryMessage
     {
         public readonly string Text;
         public readonly string Name;
@@ -57,7 +59,8 @@ public TelemetryTrace(string text, string name, string type)
     /// <summary>
     /// Message with exception
     /// </summary>
-    public sealed class TelemetryException : TelemetryMessage
+    [BestFriend]
+    internal sealed class TelemetryException : TelemetryMessage
     {
         public readonly Exception Exception;
         public TelemetryException(Exception exception)
@@ -70,7 +73,8 @@ public TelemetryException(Exception exception)
     /// <summary>
     /// Message with metric value and it properites
     /// </summary>
-    public sealed class TelemetryMetric : TelemetryMessage
+    [BestFriend]
+    internal sealed class TelemetryMetric : TelemetryMessage
     {
         public readonly string Name;
         public readonly double Value;

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

@@ -56,7 +56,8 @@ public abstract class ArgumentsBase
             public KeyValuePair<string, IComponentFactory<IDataView, IDataTransform>>[] Transform;
         }
 
-        public abstract class ImplBase<TArgs> : ICommand
+        [BestFriend]
+        internal abstract class ImplBase<TArgs> : ICommand
             where TArgs : ArgumentsBase
         {
             protected readonly IHost Host;