Closes #36 - Performance changes to the in-memory repository

Author: johelvisguzman

src/DotNetToolkit.Repository.InMemory/InMemoryRepositoryBase.cs

@@ -164,17 +164,23 @@ protected override void AddItem(TEntity entity)
                 .Select(x => x.Key)
                 .SingleOrDefault();
 
+            var hasTemporaryKey = false;
+
             if (key != null && key.Equals(default(TKey)))
             {
                 key = GetPrimaryKey(entity);
 
                 if (key != null && key.Equals(default(TKey)))
                 {
                     key = GenerateTemporaryPrimaryKey();
+                    hasTemporaryKey = true;
                 }
             }
 
-            _context[key] = new EntitySet<TEntity, TKey>(entity, key, EntityState.Added);
+            _context[key] = new EntitySet<TEntity, TKey>(entity, key, EntityState.Added)
+            {
+                HasTemporaryKey = hasTemporaryKey
+            };
         }
 
         /// <summary>
@@ -183,13 +189,18 @@ protected override void AddItem(TEntity entity)
         protected override void DeleteItem(TEntity entity)
         {
             var key = GetPrimaryKey(entity);
+            var hasTemporaryKey = false;
 
             if (key != null && key.Equals(default(TKey)))
             {
                 key = GenerateTemporaryPrimaryKey();
+                hasTemporaryKey = true;
             }
 
-            _context[key] = new EntitySet<TEntity, TKey>(entity, key, EntityState.Removed);
+            _context[key] = new EntitySet<TEntity, TKey>(entity, key, EntityState.Removed)
+            {
+                HasTemporaryKey = hasTemporaryKey
+            };
         }
 
         /// <summary>
@@ -198,13 +209,18 @@ protected override void DeleteItem(TEntity entity)
         protected override void UpdateItem(TEntity entity)
         {
             var key = GetPrimaryKey(entity);
+            var hasTemporaryKey = false;
 
             if (key != null && key.Equals(default(TKey)))
             {
                 key = GenerateTemporaryPrimaryKey();
+                hasTemporaryKey = true;
             }
 
-            _context[key] = new EntitySet<TEntity, TKey>(entity, key, EntityState.Modified);
+            _context[key] = new EntitySet<TEntity, TKey>(entity, key, EntityState.Modified)
+            {
+                HasTemporaryKey = hasTemporaryKey
+            };
         }
 
         /// <summary>
@@ -218,29 +234,28 @@ protected override void SaveChanges()
 
                 foreach (var entitySet in _context.Select(y => y.Value))
                 {
-                    var temporaryKey = entitySet.Key;
-                    var key = GetPrimaryKey(entitySet.Entity);
+                    var key = entitySet.Key;
 
                     if (entitySet.State == EntityState.Added)
                     {
-                        if (key == null || key.Equals(default(TKey)))
+                        if (entitySet.HasTemporaryKey)
                         {
                             key = GeneratePrimaryKey();
                             SetPrimaryKey(entitySet.Entity, key);
                         }
-                        else if (context.ContainsKey(temporaryKey))
+                        else if (context.ContainsKey(key))
                         {
                             throw new InvalidOperationException(string.Format(CultureInfo.CurrentCulture, Resources.EntityAlreadyBeingTrackedInStore, entitySet.Entity.GetType()));
                         }
                     }
-                    else if (!context.ContainsKey(temporaryKey))
+                    else if (!context.ContainsKey(key))
                     {
                         throw new InvalidOperationException(Resources.EntityNotFoundInStore);
                     }
 
                     if (entitySet.State == EntityState.Removed)
                     {
-                        context.Remove(temporaryKey);
+                        context.Remove(key);
                     }
                     else
                     {
@@ -261,8 +276,8 @@ protected override IQueryable<TEntity> GetQuery(IFetchStrategy<TEntity> fetchStr
         {
             return InMemoryCache<TEntity, TKey>.Instance
                 .GetContext(DatabaseName)
-                .AsQueryable()
-                .Select(y => y.Value);
+                .Select(y => y.Value)
+                .AsQueryable();
         }
 
         /// <summary>
@@ -320,6 +335,11 @@ public EntitySet(TEntity entity, TKey key, EntityState state)
             /// </summary>
             public EntityState State { get; }
 
+            /// <summary>
+            /// Gets or sets a value indicating whether this instance has a temporary key.
+            /// </summary>
+            public bool HasTemporaryKey { get; set; }
+
             #endregion
         }
 
@@ -334,8 +354,7 @@ private enum EntityState
         {
             Added,
             Removed,
-            Modified,
-            Unchanged
+            Modified
         }
 
         #endregion