Improving the support for idempotency behavior, providing repositorie…

…s that track changes of the returned entities

Deveel.Repository.sln

@@ -54,10 +54,12 @@ Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Deveel.Repository.Manager.E
 EndProject
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Deveel.Repository.Finbuckle.MultiTenant", "src\Deveel.Repository.Finbuckle.MultiTenant\Deveel.Repository.Finbuckle.MultiTenant.csproj", "{69E01D54-C430-4A1E-989E-5A61AB4C5B54}"
 EndProject
-Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Deveel.Repository.Management.Tests", "test\Deveel.Repository.Management.Tests\Deveel.Repository.Management.Tests.csproj", "{7DC0EA52-DAAB-49D4-8443-3409C001E27E}"
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Deveel.Repository.Management.Tests", "test\Deveel.Repository.Management.Tests\Deveel.Repository.Management.Tests.csproj", "{7DC0EA52-DAAB-49D4-8443-3409C001E27E}"
 EndProject
 Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "management", "management", "{85200FA4-CC68-4758-B6E5-287E8AFA79FE}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Deveel.Repository.Finbuckle.MultiTenant.XUnit", "test\Deveel.Repository.Finbuckle.MultiTenant.XUnit\Deveel.Repository.Finbuckle.MultiTenant.XUnit.csproj", "{BE852D51-A08A-4151-A8C1-396096F0AB52}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -140,6 +142,10 @@ Global
 		{7DC0EA52-DAAB-49D4-8443-3409C001E27E}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{7DC0EA52-DAAB-49D4-8443-3409C001E27E}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{7DC0EA52-DAAB-49D4-8443-3409C001E27E}.Release|Any CPU.Build.0 = Release|Any CPU
+		{BE852D51-A08A-4151-A8C1-396096F0AB52}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{BE852D51-A08A-4151-A8C1-396096F0AB52}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{BE852D51-A08A-4151-A8C1-396096F0AB52}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{BE852D51-A08A-4151-A8C1-396096F0AB52}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
@@ -165,6 +171,7 @@ Global
 		{69E01D54-C430-4A1E-989E-5A61AB4C5B54} = {2860FD4D-510F-43C8-870E-5559B90D0CAD}
 		{7DC0EA52-DAAB-49D4-8443-3409C001E27E} = {85200FA4-CC68-4758-B6E5-287E8AFA79FE}
 		{85200FA4-CC68-4758-B6E5-287E8AFA79FE} = {50434E05-0F21-4871-AFB3-A483CEE4A300}
+		{BE852D51-A08A-4151-A8C1-396096F0AB52} = {50434E05-0F21-4871-AFB3-A483CEE4A300}
 	EndGlobalSection
 	GlobalSection(ExtensibilityGlobals) = postSolution
 		SolutionGuid = {01FD9B16-84B3-4D99-80C1-11B2F3D65B56}

src/Deveel.Repository.Core/Data/ITrackingRepository_T.cs

@@ -0,0 +1,12 @@
+namespace Deveel.Data {
+	/// <summary>
+	/// Defines a repository that is able to track changes 
+	/// on entities returned by queries.
+	/// </summary>
+	/// <typeparam name="TEntity">
+	/// The type of entity managed by the repository.
+	/// </typeparam>
+	public interface ITrackingRepository<TEntity> : ITrackingRepository<TEntity, object>
+		where TEntity : class {
+	}
+}

src/Deveel.Repository.Core/Data/ITrackingRepository_T2.cs

@@ -0,0 +1,42 @@
+namespace Deveel.Data {
+	/// <summary>
+	/// Defines a repository that is able to track changes 
+	/// on entities returned by queries.
+	/// </summary>
+	/// <typeparam name="TEntity">
+	/// The type of entity managed by the repository.
+	/// </typeparam>
+	/// <typeparam name="TKey">
+	/// The type of the key used to identify the entity.
+	/// </typeparam>
+	public interface ITrackingRepository<TEntity, TKey> : IRepository<TEntity, TKey>
+		where TEntity : class {
+		/// <summary>
+		/// Gets a value indicating if the repository is tracking
+		/// changes on entities.
+		/// </summary>
+		/// <remarks>
+		/// A repository implementation of this contract might
+		/// be configured not to track changes on entities, in
+		/// this case the value of this property is <c>false</c>.
+		/// </remarks>
+		bool IsTrackingChanges { get; }
+
+		/// <summary>
+		/// Finds the original entity that is being tracked by the repository,
+		/// as it was loaded from the data source.
+		/// </summary>
+		/// <param name="key">
+		/// The key that identifies the entity.
+		/// </param>
+		/// <param name="cancellationToken">
+		/// A cancellation token that can be used to cancel the operation.
+		/// </param>
+		/// <returns>
+		/// Returns the original version of entity that is being tracked by the repository,
+		/// as it was loaded from the data source, or <c>null</c> if the entity is not
+		/// found or it's not being tracked.
+		/// </returns>
+		Task<TEntity?> FindOriginalAsync(TKey key, CancellationToken cancellationToken = default);
+	}
+}

src/Deveel.Repository.EntityFramework/Data/EntityRepository_T.cs

@@ -30,7 +30,8 @@ public class EntityRepository<TEntity> : EntityRepository<TEntity, object>,
         IRepository<TEntity>,
         IFilterableRepository<TEntity>,
         IQueryableRepository<TEntity>,
-		IPageableRepository<TEntity>
+		IPageableRepository<TEntity>,
+		ITrackingRepository<TEntity>
         where TEntity : class {
 
 		/// <summary>

src/Deveel.Repository.EntityFramework/Data/EntityRepository_T2.cs

@@ -39,6 +39,7 @@ public class EntityRepository<TEntity, TKey> :
 		IFilterableRepository<TEntity, TKey>,
 		IQueryableRepository<TEntity, TKey>,
 		IPageableRepository<TEntity, TKey>,
+		ITrackingRepository<TEntity, TKey>,
 		IDisposable
 		where TEntity : class {
 		private bool disposedValue;
@@ -130,6 +131,8 @@ internal EntityRepository(DbContext context, ITenantInfo? tenantInfo, ILogger? l
 		protected bool IsTrackingChanges => Entities.Local != null ||
 			Context.ChangeTracker.QueryTrackingBehavior != QueryTrackingBehavior.NoTracking;
 
+		bool ITrackingRepository<TEntity, TKey>.IsTrackingChanges => IsTrackingChanges;
+
 		/// <summary>
 		/// Gets the information about the tenant that the repository is using to access the data.
 		/// </summary>
@@ -448,8 +451,7 @@ public virtual async Task<long> CountAsync(IQueryFilter filter, CancellationToke
 				if (result == null)
 					return result;
 
-				if (result != null)
-					result = await OnEntityFoundByKeyAsync(key, result, cancellationToken);
+				result = await OnEntityFoundByKeyAsync(key, result, cancellationToken);
 
 				return result;
 			} catch (Exception ex) {
@@ -458,6 +460,23 @@ public virtual async Task<long> CountAsync(IQueryFilter filter, CancellationToke
 			}
 		}
 
+		/// <inheritdoc/>
+		public virtual async Task<TEntity?> FindOriginalAsync(TKey key, CancellationToken cancellationToken = default) {
+			ThrowIfDisposed();
+
+			try {
+				var result = await Entities.FindAsync(new object?[] { ConvertEntityKey(key) }, cancellationToken);
+				if (result == null)
+					return result;
+
+				var entry = Context.Entry(result);
+				return (TEntity) entry.OriginalValues.ToObject();
+			} catch (Exception ex) {
+				Logger.LogUnknownError(ex, typeof(TEntity));
+				throw new RepositoryException("Unable to find an entity int he repository because of an error", ex);
+			}
+		}
+
 		/// <inheritdoc/>
 		public virtual async Task<IList<TEntity>> FindAllAsync(IQuery query, CancellationToken cancellationToken = default) {
 			try {

src/Deveel.Repository.Finbuckle.MultiTenant/Data/RepositoryTenantResolver.cs

@@ -12,12 +12,6 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Text;
-using System.Threading.Tasks;
-
 using Finbuckle.MultiTenant;
 
 namespace Deveel.Data {

src/Deveel.Repository.InMemory/Data/InMemoryRepository_T2.cs

@@ -13,7 +13,6 @@
 // limitations under the License.
 
 using System.ComponentModel.DataAnnotations;
-using System.Globalization;
 using System.Linq.Expressions;
 using System.Reflection;
 using System.Runtime.Serialization;
@@ -34,11 +33,12 @@ public class InMemoryRepository<TEntity, TKey> :
 		IQueryableRepository<TEntity, TKey>,
 		IPageableRepository<TEntity, TKey>,
 		IFilterableRepository<TEntity, TKey>,
+		ITrackingRepository<TEntity, TKey>,
 		IMultiTenantRepository<TEntity, TKey>,
 		IDisposable
 		where TEntity : class 
 		where TKey : notnull {
-		private SortedList<TKey, TEntity> entities;
+		private SortedList<TKey, Entry> entities;
 		private bool disposedValue;
 		private MemberInfo? idMember;
 		private readonly IFieldMapper<TEntity>? fieldMapper;
@@ -91,10 +91,13 @@ protected InMemoryRepository(string tenantId,
 
 		IQueryable<TEntity> IQueryableRepository<TEntity, TKey>.AsQueryable() => Entities.AsQueryable();
 
+		bool ITrackingRepository<TEntity, TKey>.IsTrackingChanges => true;
+
 		/// <summary>
 		/// Gets the read-only list of entities in the repository.
 		/// </summary>
-		public virtual IReadOnlyList<TEntity> Entities => entities.Values.ToList().AsReadOnly();
+		public virtual IReadOnlyList<TEntity> Entities => entities.Values.Select(x => x.Entity)
+			.ToList().AsReadOnly();
 
 		string? IMultiTenantRepository<TEntity, TKey>.TenantId => TenantId;
 
@@ -104,25 +107,29 @@ protected InMemoryRepository(string tenantId,
 		/// </summary>
 		protected virtual string? TenantId { get; }
 
-		private SortedList<TKey, TEntity> CopyList(IEnumerable<TEntity> source) {
-			var result = new SortedList<TKey, TEntity>();
+		private SortedList<TKey, Entry> CopyList(IEnumerable<TEntity> source) {
+			var result = new SortedList<TKey, Entry>();
 			foreach (var item in source) {
 				var id = GetEntityId(item);
 				if (id == null)
 					throw new RepositoryException("The entity does not have an ID");
 
-				result.Add(id, Clone(item));
+				result.Add(id, new Entry(item));
 			}
 
 			return result;
 		}
 
 		private static TEntity Clone(TEntity entity) {
-			var serializer = new DataContractSerializer(typeof(TEntity));
-			using var stream = new MemoryStream();
-			serializer.WriteObject(stream, entity);
-			stream.Position = 0;
-			return (TEntity)serializer.ReadObject(stream)!;
+			var cloneMethod = typeof(TEntity)
+				.GetMethod("MemberwiseClone", BindingFlags.Instance | BindingFlags.NonPublic);
+
+			return (TEntity)cloneMethod!.Invoke(entity, new object[0])!;
+			//var serializer = new DataContractSerializer(typeof(TEntity));
+			//using var stream = new MemoryStream();
+			//serializer.WriteObject(stream, entity);
+			//stream.Position = 0;
+			//return (TEntity)serializer.ReadObject(stream)!;
 		}
 
 		/// <inheritdoc/>
@@ -192,7 +199,7 @@ public Task<long> CountAsync(IQueryFilter filter, CancellationToken cancellation
 			cancellationToken.ThrowIfCancellationRequested();
 
 			try {
-				var result = entities.Values.AsQueryable().LongCount(filter);
+				var result = Entities.AsQueryable().LongCount(filter);
 				return Task.FromResult(result);
 			} catch (Exception ex) {
 				throw new RepositoryException("Could not count the entities", ex);
@@ -207,7 +214,7 @@ public Task AddAsync(TEntity entity, CancellationToken cancellationToken = defau
 				var key = GenerateNewKey();
 				SetEntityId(entity, key);
 
-				entities.Add(key, Clone(entity));
+				entities.Add(key, new Entry(entity));
 
 				return Task.CompletedTask;
 			} catch (RepositoryException) {
@@ -227,7 +234,7 @@ public Task AddRangeAsync(IEnumerable<TEntity> entities, CancellationToken cance
 					var key = GenerateNewKey();
 					SetEntityId(item, key);
 
-					this.entities.Add(key, Clone(item));
+					this.entities.Add(key, new Entry(item));
 				}
 
 				return Task.CompletedTask;
@@ -302,7 +309,7 @@ public Task<bool> ExistsAsync(IQueryFilter filter, CancellationToken cancellatio
 			cancellationToken.ThrowIfCancellationRequested();
 
 			try {
-				var result = entities.Values.AsQueryable().Any(filter);
+				var result = Entities.AsQueryable().Any(filter);
 				return Task.FromResult(result);
 			} catch (Exception ex) {
 				throw new RepositoryException("Could not check if any entities exist in the repository", ex);
@@ -315,7 +322,7 @@ public Task<IList<TEntity>> FindAllAsync(IQuery query, CancellationToken cancell
 			cancellationToken.ThrowIfCancellationRequested();
 
 			try {
-				var result = query.Apply(entities.Values.AsQueryable()).ToList();
+				var result = query.Apply(Entities.AsQueryable()).ToList();
 
 				return Task.FromResult<IList<TEntity>>(result);
 			} catch (Exception ex) {
@@ -329,13 +336,28 @@ public Task<IList<TEntity>> FindAllAsync(IQuery query, CancellationToken cancell
 			cancellationToken.ThrowIfCancellationRequested();
 
 			try {
-				var result = query.Apply(entities.Values.AsQueryable()).FirstOrDefault();
+				var result = query.Apply(Entities.AsQueryable()).FirstOrDefault();
 				return Task.FromResult(result);
 			} catch (Exception ex) {
 				throw new RepositoryException("Error while searching for any entities in the repository matching the filter", ex);
 			}
 		}
 
+		/// <inheritdoc/>
+		public Task<TEntity?> FindOriginalAsync(TKey key, CancellationToken cancellationToken = default) {
+			ArgumentNullException.ThrowIfNull(key, nameof(key));
+			cancellationToken.ThrowIfCancellationRequested();
+
+			try {
+				if (!entities.TryGetValue(key, out var entry))
+					return Task.FromResult<TEntity?>(null);
+
+				return Task.FromResult<TEntity?>(entry.Original);
+			} catch (Exception ex) {
+				throw new RepositoryException("Error while searching any entities with the given ID", ex);
+			}
+		}
+
 		/// <inheritdoc/>
 		public Task<TEntity?> FindAsync(TKey key, CancellationToken cancellationToken = default) {
 			ArgumentNullException.ThrowIfNull(key, nameof(key));
@@ -346,7 +368,7 @@ public Task<IList<TEntity>> FindAllAsync(IQuery query, CancellationToken cancell
 				if (!entities.TryGetValue(key, out var entity))
 					return Task.FromResult<TEntity?>(null);
 
-				return Task.FromResult<TEntity?>(entity);
+				return Task.FromResult<TEntity?>(entity.Entity);
 			} catch (Exception ex) {
 				throw new RepositoryException("Error while searching any entities with the given ID", ex);
 			}
@@ -377,7 +399,7 @@ public Task<PageResult<TEntity>> GetPageAsync(PageQuery<TEntity> request, Cancel
 			cancellationToken.ThrowIfCancellationRequested();
 
 			try {
-				var entitySet = request.ApplyQuery(entities.Values.AsQueryable());
+				var entitySet = request.ApplyQuery(Entities.AsQueryable());
 
 				var itemCount = entitySet.Count();
 				var items = entitySet
@@ -403,10 +425,10 @@ public Task<bool> UpdateAsync(TEntity entity, CancellationToken cancellationToke
 				if (entityId == null)
 					return Task.FromResult(false);
 
-				if (!entities.TryGetValue(entityId, out var existing))
+				if (!entities.TryGetValue(entityId, out var entry))
 					return Task.FromResult(false);
 
-				entities[entityId] = entity;
+				entry.Entity = entity;
 				return Task.FromResult(true);
 			} catch (Exception ex) {
 				throw new RepositoryException("Unable to update the entity", ex);
@@ -438,5 +460,16 @@ public void Dispose() {
 			Dispose(disposing: true);
 			GC.SuppressFinalize(this);
 		}
+
+		class Entry {
+			public Entry(TEntity entity) {
+				Entity = entity;
+				Original = Clone(entity);
+			}
+
+			public TEntity Original { get; }
+
+			public TEntity Entity { get; set; }
+		}
 	}
 }

src/Deveel.Repository.Manager/Data/EntityManager_T.cs

@@ -64,6 +64,27 @@ public EntityManager(
 			ILoggerFactory? loggerFactory = null) : base(repository, WrapValidator(validator), cache, systemTime, errorFactory, services, loggerFactory) {
 		}
 
+		/// <inheritdoc/>
+		public override bool IsTrackingChanges {
+			get {
+				ThrowIfDisposed();
+
+				return (Repository is ITrackingRepository<TEntity> trackingRepository);
+			}
+		}
+
+		/// <inheritdoc/>
+		protected override ITrackingRepository<TEntity, object> TrackingRepository {
+			get {
+				ThrowIfDisposed();
+
+				if (!(Repository is ITrackingRepository<TEntity> trackingRepository))
+					throw new InvalidOperationException("The repository is not tracking changes.");
+
+				return trackingRepository;
+			}
+		}
+
 		private static IEntityValidator<TEntity, object>? WrapValidator(IEntityValidator<TEntity>? validator) => 
 			validator == null ? null : new EntityValidatorWrapper(validator);