Introduced type-based serialization interception.

src/ExtendedXmlSerializer/ContentModel/RuntimeSerializer.cs

@@ -2,7 +2,6 @@
 using ExtendedXmlSerializer.ContentModel.Format;
 using ExtendedXmlSerializer.ContentModel.Reflection;
 using JetBrains.Annotations;
-using System.Reflection;
 
 namespace ExtendedXmlSerializer.ContentModel
 {
@@ -20,13 +19,9 @@ public RuntimeSerializer(IRuntimeSerialization serialization, IClassification cl
 
 		public void Write(IFormatWriter writer, object instance)
 		{
-			var typeInfo = instance.GetType()
-			                       .GetTypeInfo();
-			_serialization.Get(typeInfo)
-			              .Write(writer, instance);
+			_serialization.Get(instance.GetType()).Write(writer, instance);
 		}
 
-		public object Get(IFormatReader reader) => _serialization.Get(_classification.Get(reader))
-		                                                         .Get(reader);
+		public object Get(IFormatReader reader) => _serialization.Get(_classification.Get(reader)).Get(reader);
 	}
 }

src/ExtendedXmlSerializer/ExtensionMethodsForContent.cs

@@ -94,6 +94,34 @@ public static ITypeConfiguration<T> WithMonitor<T>(this ITypeConfiguration<T> @t
 			        .Apply(Support<T>.Metadata, new SerializationMonitor<T>(monitor))
 			        .Return(@this);
 
+		/// <summary>
+		/// Applies an interceptor for type configuration.  An interceptor participates in the serialization pipeline by being
+		/// introduced during key serialization and deserialization events.
+		/// </summary>
+		/// <param name="this">The type to intercept.</param>
+		/// <param name="interceptor">The interceptor to apply to a type.</param>
+		/// <typeparam name="T">The type argument of the type configuration being configured.</typeparam>
+		/// <returns>The configured type configuration.</returns>
+		/// <seealso href="https://github.com/ExtendedXmlSerializer/home/issues/451" />
+		public static ITypeConfiguration<T> WithInterceptor<T>(this ITypeConfiguration<T> @this,
+		                                                       ISerializationInterceptor<T> interceptor)
+			=> @this.WithInterceptor(new SerializationInterceptor<T>(interceptor));
+
+		/// <summary>
+		/// Applies a generalized interceptor for type configuration.  An interceptor participates in the serialization pipeline by being
+		/// introduced during key serialization and deserialization events.
+		/// </summary>
+		/// <param name="this">The type to intercept.</param>
+		/// <param name="interceptor">The interceptor to apply to a type.</param>
+		/// <typeparam name="T">The type argument of the type configuration being configured.</typeparam>
+		/// <returns>The configured type configuration.</returns>
+		/// <seealso href="https://github.com/ExtendedXmlSerializer/home/issues/451" />
+		public static ITypeConfiguration<T> WithInterceptor<T>(this ITypeConfiguration<T> @this,
+		                                                       ISerializationInterceptor interceptor)
+			=> @this.Root.With<SerializationInterceptionExtension>()
+			        .Apply(Support<T>.Metadata, interceptor)
+			        .Return(@this);
+
 		/// <summary>
 		/// Allows content to be read as parameters for a constructor call to activate an object, rather than the more
 		/// traditional route of activating an object and its content read as property assignments.  This is preferred --
@@ -310,23 +338,23 @@ public static IMemberConfiguration Include(this IMemberConfiguration @this)
 
 		/// <exclude />
 		[Obsolete(
-			"This method is being deprecated and will be removed in a future release. Use Decorate.Element.When instead.")]
+			         "This method is being deprecated and will be removed in a future release. Use Decorate.Element.When instead.")]
 		public static IServiceRepository Decorate<T>(this IServiceRepository @this,
 		                                             ISpecification<TypeInfo> specification)
 			where T : IElement
 			=> new ConditionalElementDecoration<T>(specification).Get(@this);
 
 		/// <exclude />
 		[Obsolete(
-			"This method is being deprecated and will be removed in a future release. Use Decorate.Contents.When instead.")]
+			         "This method is being deprecated and will be removed in a future release. Use Decorate.Contents.When instead.")]
 		public static IServiceRepository DecorateContent<TSpecification, T>(this IServiceRepository @this)
 			where TSpecification : ISpecification<TypeInfo>
 			where T : IContents
 			=> ConditionalContentDecoration<TSpecification, T>.Default.Get(@this);
 
 		/// <exclude />
 		[Obsolete(
-			"This method is being deprecated and will be removed in a future release. Use Decorate.Contents.When instead.")]
+			         "This method is being deprecated and will be removed in a future release. Use Decorate.Contents.When instead.")]
 		public static IServiceRepository DecorateContent<T>(this IServiceRepository @this,
 		                                                    ISpecification<TypeInfo> specification) where T : IContents
 			=> new ConditionalContentDecoration<T>(specification).Get(@this);
@@ -344,13 +372,13 @@ public static IConfigurationContainer OptimizeConverters(this IConfigurationCont
 
 		/// <exclude />
 		[Obsolete(
-			"This method will be removed in a future release.  Use IConfigurationContainer.IncludeConfiguredMembers instead.")]
+			         "This method will be removed in a future release.  Use IConfigurationContainer.IncludeConfiguredMembers instead.")]
 		public static IConfigurationContainer OnlyConfiguredProperties(this IConfigurationContainer @this)
 			=> @this.IncludeConfiguredMembers();
 
 		/// <exclude />
 		[Obsolete(
-			"This method will be removed in a future release.  Use ITypeConfiguration<T>.IncludeConfiguredMembers instead.")]
+			         "This method will be removed in a future release.  Use ITypeConfiguration<T>.IncludeConfiguredMembers instead.")]
 		public static ITypeConfiguration<T> OnlyConfiguredProperties<T>(this ITypeConfiguration<T> @this)
 			=> @this.IncludeConfiguredTypeMembers()
 			        .Return(@this);

src/ExtendedXmlSerializer/ExtensionModel/Instances/ISerializationInterceptor.cs

@@ -0,0 +1,39 @@
+using ExtendedXmlSerializer.ContentModel.Format;
+using System;
+
+namespace ExtendedXmlSerializer.ExtensionModel.Instances
+{
+	/// <inheritdoc />
+	public interface ISerializationInterceptor : ISerializationInterceptor<object> {}
+
+	/// <summary>
+	/// Provides a mechanism to partake in the serialization pipeline.
+	/// </summary>
+	/// <typeparam name="T">The type to serialize.</typeparam>
+	/// <seealso href="https://github.com/ExtendedXmlSerializer/home/issues/451" />
+	public interface ISerializationInterceptor<T>
+	{
+		/// <summary>
+		/// Called when an instance is being serialized.
+		/// </summary>
+		/// <param name="writer">The writer performing the serialization.</param>
+		/// <param name="instance">The instance to serialize.</param>
+		/// <returns>The actual instance to serialize.</returns>
+		T Serializing(IFormatWriter writer, T instance);
+
+		/// <summary>
+		/// Returns the instance to activate during deserialization.  If `null` is returned, the default internal infrastructure is used to activate the object.
+		/// </summary>
+		/// <param name="instanceType">The type to activate.</param>
+		/// <returns>An instance of the provided type to activate.  If `null`, the default internal activation is used.</returns>
+		T Activating(Type instanceType);
+
+		/// <summary>
+		/// Called after an object has been activated and properties have been assigned their values from deserialization.
+		/// </summary>
+		/// <param name="reader">The reader used to deserialize the provided instance</param>
+		/// <param name="instance">The instance that was deserialized.</param>
+		/// <returns>The actual instance deserialized.</returns>
+		T Deserialized(IFormatReader reader, T instance);
+	}
+}

src/ExtendedXmlSerializer/ExtensionModel/Instances/SerializationActivator.cs

@@ -0,0 +1,20 @@
+using ExtendedXmlSerializer.ContentModel.Format;
+using System;
+
+namespace ExtendedXmlSerializer.ExtensionModel.Instances
+{
+	/// <summary>
+	/// A generalized serialization interceptor base class for convenience.
+	/// </summary>
+	public abstract class SerializationActivator : ISerializationInterceptor
+	{
+		/// <inheritdoc />
+		public virtual object Serializing(IFormatWriter writer, object instance) => instance;
+
+		/// <inheritdoc />
+		public abstract object Activating(Type instanceType);
+
+		/// <inheritdoc />
+		public virtual object Deserialized(IFormatReader reader, object instance) => instance;
+	}
+}

src/ExtendedXmlSerializer/ExtensionModel/Instances/SerializationInterceptionExtension.cs

@@ -0,0 +1,145 @@
+using ExtendedXmlSerializer.ContentModel;
+using ExtendedXmlSerializer.ContentModel.Content;
+using ExtendedXmlSerializer.ContentModel.Format;
+using ExtendedXmlSerializer.Core;
+using ExtendedXmlSerializer.Core.Sources;
+using ExtendedXmlSerializer.Core.Specifications;
+using ExtendedXmlSerializer.ReflectionModel;
+using JetBrains.Annotations;
+using System;
+using System.Reflection;
+
+namespace ExtendedXmlSerializer.ExtensionModel.Instances
+{
+	sealed class SerializationInterceptionExtension
+		: ISerializerExtension, IAssignable<TypeInfo, ISerializationInterceptor>
+	{
+		readonly ITypedTable<ISerializationInterceptor> _registrations;
+
+		[UsedImplicitly]
+		public SerializationInterceptionExtension() : this(new TypedTable<ISerializationInterceptor>()) {}
+
+		public SerializationInterceptionExtension(ITypedTable<ISerializationInterceptor> registrations)
+			=> _registrations = registrations;
+
+		public IServiceRepository Get(IServiceRepository parameter)
+			=> parameter.Decorate<IActivatingTypeSpecification>(Register)
+			            .Decorate<IActivators>(Register)
+			            .Decorate<IContents>(Register);
+
+		IContents Register(IServiceProvider _, IContents previous) => new Contents(_registrations, previous);
+
+		IActivatingTypeSpecification Register(IServiceProvider _, IActivatingTypeSpecification previous)
+			=> new IsActivatingType(_registrations, previous);
+
+		IActivators Register(IServiceProvider _, IActivators previous) => new Activators(_registrations, previous);
+
+		void ICommand<IServices>.Execute(IServices parameter) {}
+
+		sealed class IsActivatingType : AnySpecification<TypeInfo>, IActivatingTypeSpecification
+		{
+			public IsActivatingType(ISpecification<TypeInfo> specification, IActivatingTypeSpecification previous)
+				: base(specification, previous) {}
+		}
+
+		sealed class Contents : IContents
+		{
+			readonly ITypedTable<ISerializationInterceptor> _interceptors;
+			readonly IContents                              _contents;
+
+			public Contents(ITypedTable<ISerializationInterceptor> interceptors, IContents contents)
+			{
+				_interceptors = interceptors;
+				_contents     = contents;
+			}
+
+			public ISerializer Get(TypeInfo parameter)
+			{
+				var previous = _contents.Get(parameter);
+				var result   = _interceptors.IsSatisfiedBy(parameter) ? Create(parameter, previous) : previous;
+				return result;
+			}
+
+			Serializer Create(TypeInfo parameter, ISerializer previous)
+			{
+				var interceptor = _interceptors.Get(parameter);
+				var result      = new Serializer(new Reader(interceptor, previous), new Writer(interceptor, previous));
+				return result;
+			}
+		}
+
+		sealed class Activators : IActivators
+		{
+			readonly ITypedTable<ISerializationInterceptor> _table;
+			readonly IActivators                            _previous;
+
+			public Activators(ITypedTable<ISerializationInterceptor> table, IActivators previous)
+			{
+				_table    = table;
+				_previous = previous;
+			}
+
+			public IActivator Get(Type parameter)
+				=> _table.IsSatisfiedBy(parameter)
+					   ? new Activator(parameter, _previous.Build(parameter), _table.Get(parameter))
+					   : _previous.Get(parameter);
+
+			sealed class Activator : IActivator
+			{
+				readonly Type                      _instanceType;
+				readonly Func<IActivator>          _activator;
+				readonly ISerializationInterceptor _interceptor;
+
+				public Activator(Type instanceType, Func<IActivator> activator, ISerializationInterceptor interceptor)
+				{
+					_instanceType = instanceType;
+					_activator    = activator;
+					_interceptor  = interceptor;
+				}
+
+				public object Get() => _interceptor.Activating(_instanceType) ?? _activator().Get();
+			}
+		}
+
+		sealed class Writer : IWriter
+		{
+			readonly ISerializationInterceptor _interceptor;
+			readonly IWriter                   _writer;
+
+			public Writer(ISerializationInterceptor interceptor, IWriter writer)
+			{
+				_interceptor = interceptor;
+				_writer      = writer;
+			}
+
+			public void Write(IFormatWriter writer, object instance)
+			{
+				_writer.Write(writer, _interceptor.Serializing(writer, instance));
+			}
+		}
+
+		sealed class Reader : IReader
+		{
+			readonly ISerializationInterceptor _interceptor;
+			readonly IReader                   _reader;
+
+			public Reader(ISerializationInterceptor interceptor, IReader reader)
+			{
+				_interceptor = interceptor;
+				_reader      = reader;
+			}
+
+			public object Get(IFormatReader parameter)
+			{
+				var instance = _reader.Get(parameter);
+				var result   = _interceptor.Deserialized(parameter, instance);
+				return result;
+			}
+		}
+
+		public void Assign(TypeInfo key, ISerializationInterceptor value)
+		{
+			_registrations.Assign(key, value);
+		}
+	}
+}

src/ExtendedXmlSerializer/ExtensionModel/Instances/SerializationInterceptor.cs

@@ -0,0 +1,20 @@
+using ExtendedXmlSerializer.ContentModel.Format;
+using System;
+
+namespace ExtendedXmlSerializer.ExtensionModel.Instances
+{
+	sealed class SerializationInterceptor<T> : ISerializationInterceptor
+	{
+		readonly ISerializationInterceptor<T> _interceptor;
+
+		public SerializationInterceptor(ISerializationInterceptor<T> interceptor) => _interceptor = interceptor;
+
+		public object Serializing(IFormatWriter writer, object instance)
+			=> _interceptor.Serializing(writer, (T)instance);
+
+		public object Activating(Type instanceType) => _interceptor.Activating(instanceType);
+
+		public object Deserialized(IFormatReader reader, object instance)
+			=> _interceptor.Deserialized(reader, (T)instance);
+	}
+}