CSHARP-5335: New serializers for immutable collections (#1508)

Author: papafe

src/MongoDB.Bson/Serialization/CollectionsSerializationProvider.cs

@@ -16,6 +16,9 @@
 using System;
 using System.Collections;
 using System.Collections.Generic;
+#if NET6_0_OR_GREATER
+using System.Collections.Immutable;
+#endif
 using System.Collections.ObjectModel;
 using System.Dynamic;
 using System.Linq;
@@ -43,7 +46,17 @@ static CollectionsSerializationProvider()
                 { typeof(ReadOnlyCollection<>), typeof(ReadOnlyCollectionSerializer<>) },
                 { typeof(Stack<>), typeof(StackSerializer<>) },
                 { typeof(Memory<>), typeof(MemorySerializer<>) },
-                { typeof(ReadOnlyMemory<>), typeof(ReadonlyMemorySerializer<>) }
+                { typeof(ReadOnlyMemory<>), typeof(ReadonlyMemorySerializer<>) },
+#if NET6_0_OR_GREATER
+                { typeof(ImmutableArray<>), typeof(ImmutableArraySerializer<>) },
+                { typeof(ImmutableList<>), typeof(ImmutableListSerializer<>) },
+                { typeof(ImmutableHashSet<>), typeof(ImmutableHashSetSerializer<>) },
+                { typeof(ImmutableSortedSet<>), typeof(ImmutableSortedSetSerializer<>) },
+                { typeof(ImmutableDictionary<,>), typeof(ImmutableDictionarySerializer<,>) },
+                { typeof(ImmutableSortedDictionary<,>), typeof(ImmutableSortedDictionarySerializer<,>) },
+                { typeof(ImmutableQueue<>), typeof(ImmutableQueueSerializer<>) },
+                { typeof(ImmutableStack<>), typeof(ImmutableStackSerializer<>) }
+#endif
             };
         }
 

src/MongoDB.Bson/Serialization/Serializers/EnumerableInterfaceImplementerSerializer.cs

@@ -27,7 +27,7 @@ namespace MongoDB.Bson.Serialization.Serializers
     public sealed class EnumerableInterfaceImplementerSerializer<TValue> :
         EnumerableInterfaceImplementerSerializerBase<TValue>,
         IChildSerializerConfigurable
-            where TValue : class, IList, new()
+            where TValue : IEnumerable, new()
     {
         // constructors
         /// <summary>
@@ -96,7 +96,7 @@ IBsonSerializer IChildSerializerConfigurable.WithChildSerializer(IBsonSerializer
     public sealed class EnumerableInterfaceImplementerSerializer<TValue, TItem> :
         EnumerableInterfaceImplementerSerializerBase<TValue, TItem>,
         IChildSerializerConfigurable
-            where TValue : class, IEnumerable<TItem>
+            where TValue : IEnumerable<TItem>
     {
         // constructors
         /// <summary>

src/MongoDB.Bson/Serialization/Serializers/EnumerableInterfaceImplementerSerializerBase.cs

@@ -22,7 +22,7 @@ namespace MongoDB.Bson.Serialization.Serializers
     /// Represents a serializer for enumerable values.
     /// </summary>
     /// <typeparam name="TValue">The type of the value.</typeparam>
-    public abstract class EnumerableInterfaceImplementerSerializerBase<TValue> : EnumerableSerializerBase<TValue>, IBsonArraySerializer where TValue : class, IEnumerable
+    public abstract class EnumerableInterfaceImplementerSerializerBase<TValue> : EnumerableSerializerBase<TValue> where TValue : IEnumerable
     {
         // constructors
         /// <summary>
@@ -87,7 +87,7 @@ protected override TValue FinalizeResult(object accumulator)
     /// </summary>
     /// <typeparam name="TValue">The type of the value.</typeparam>
     /// <typeparam name="TItem">The type of the items.</typeparam>
-    public abstract class EnumerableInterfaceImplementerSerializerBase<TValue, TItem> : EnumerableSerializerBase<TValue, TItem>, IBsonArraySerializer where TValue : class, IEnumerable<TItem>
+    public abstract class EnumerableInterfaceImplementerSerializerBase<TValue, TItem> : EnumerableSerializerBase<TValue, TItem> where TValue : IEnumerable<TItem>
     {
         // constructors
         /// <summary>

src/MongoDB.Bson/Serialization/Serializers/EnumerableSerializerBase.cs

@@ -24,7 +24,7 @@ namespace MongoDB.Bson.Serialization.Serializers
     /// Represents a base serializer for enumerable values.
     /// </summary>
     /// <typeparam name="TValue">The type of the value.</typeparam>
-    public abstract class EnumerableSerializerBase<TValue> : SerializerBase<TValue>, IBsonArraySerializer where TValue : class, IEnumerable
+    public abstract class EnumerableSerializerBase<TValue> : SerializerBase<TValue>, IBsonArraySerializer where TValue : IEnumerable
     {
         // private fields
         private readonly IDiscriminatorConvention _discriminatorConvention = new ScalarDiscriminatorConvention("_t");
@@ -93,8 +93,12 @@ public override TValue Deserialize(BsonDeserializationContext context, BsonDeser
             switch (bsonType)
             {
                 case BsonType.Null:
+                    if (typeof(TValue).IsValueType)
+                    {
+                        throw new FormatException($"Cannot deserialize a null value into a value type (type: {BsonUtils.GetFriendlyTypeName(typeof(TValue))}).");
+                    }
                     bsonReader.ReadNull();
-                    return null;
+                    return default;
 
                 case BsonType.Array:
                     bsonReader.ReadStartArray();
@@ -219,7 +223,7 @@ public override void Serialize(BsonSerializationContext context, BsonSerializati
     /// </summary>
     /// <typeparam name="TValue">The type of the value.</typeparam>
     /// <typeparam name="TItem">The type of the items.</typeparam>
-    public abstract class EnumerableSerializerBase<TValue, TItem> : SerializerBase<TValue>, IBsonArraySerializer where TValue : class, IEnumerable<TItem>
+    public abstract class EnumerableSerializerBase<TValue, TItem> : SerializerBase<TValue>, IBsonArraySerializer where TValue : IEnumerable<TItem>
     {
         // private fields
         private readonly IDiscriminatorConvention _discriminatorConvention = new ScalarDiscriminatorConvention("_t");
@@ -289,8 +293,12 @@ public override TValue Deserialize(BsonDeserializationContext context, BsonDeser
             switch (bsonType)
             {
                 case BsonType.Null:
+                    if (typeof(TValue).IsValueType)
+                    {
+                        throw new FormatException($"Cannot deserialize a null value into a value type (type: {BsonUtils.GetFriendlyTypeName(typeof(TValue))}).");
+                    }
                     bsonReader.ReadNull();
-                    return null;
+                    return default;
 
                 case BsonType.Array:
                     bsonReader.ReadStartArray();

src/MongoDB.Bson/Serialization/Serializers/ImmutableArraySerializer.cs

@@ -0,0 +1,40 @@
+/* Copyright 2010-present MongoDB Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#if NET6_0_OR_GREATER
+using System.Collections.Immutable;
+
+namespace MongoDB.Bson.Serialization.Serializers
+{
+    /// <summary>
+    /// Represents a serializer for ImmutableArrays.
+    /// </summary>
+    /// <typeparam name="T">The type of element stored by the collection.</typeparam>
+    public class ImmutableArraySerializer<T>: EnumerableInterfaceImplementerSerializerBase<ImmutableArray<T>, T>
+    {
+        /// <inheritdoc/>
+        protected override object CreateAccumulator()
+        {
+            return ImmutableArray.CreateBuilder<T>();
+        }
+
+        /// <inheritdoc/>
+        protected override ImmutableArray<T> FinalizeResult(object accumulator)
+        {
+            return ((ImmutableArray<T>.Builder)accumulator).ToImmutable();
+        }
+    }
+}
+#endif

src/MongoDB.Bson/Serialization/Serializers/ImmutableDictionarySerializer.cs

@@ -0,0 +1,42 @@
+/* Copyright 2010-present MongoDB Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#if NET6_0_OR_GREATER
+using System.Collections.Generic;
+using System.Collections.Immutable;
+
+namespace MongoDB.Bson.Serialization.Serializers
+{
+    /// <summary>
+    /// Represents a serializer for ImmutableDictionaries.
+    /// </summary>
+    /// <typeparam name="TKey">The type of the keys in the dictionary.</typeparam>
+    /// <typeparam name="TValue">The type of the values in the dictionary.</typeparam>
+    public class ImmutableDictionarySerializer<TKey, TValue>: DictionaryInterfaceImplementerSerializer<ImmutableDictionary<TKey, TValue>, TKey, TValue>
+    {
+        /// <inheritdoc/>
+        protected override ICollection<KeyValuePair<TKey, TValue>> CreateAccumulator()
+        {
+            return ImmutableDictionary.CreateBuilder<TKey, TValue>();
+        }
+
+        /// <inheritdoc/>
+        protected override ImmutableDictionary<TKey, TValue> FinalizeAccumulator(ICollection<KeyValuePair<TKey, TValue>> accumulator)
+        {
+            return ((ImmutableDictionary<TKey, TValue>.Builder)accumulator).ToImmutable();
+        }
+    }
+}
+#endif

src/MongoDB.Bson/Serialization/Serializers/ImmutableHashSetSerializer.cs

@@ -0,0 +1,40 @@
+/* Copyright 2010-present MongoDB Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#if NET6_0_OR_GREATER
+using System.Collections.Immutable;
+
+namespace MongoDB.Bson.Serialization.Serializers
+{
+    /// <summary>
+    /// Represents a serializer for ImmutableHashSets.
+    /// </summary>
+    /// <typeparam name="T">The type of element stored by the collection.</typeparam>
+    public class ImmutableHashSetSerializer<T>: EnumerableInterfaceImplementerSerializerBase<ImmutableHashSet<T>, T>
+    {
+        /// <inheritdoc/>
+        protected override object CreateAccumulator()
+        {
+            return ImmutableHashSet.CreateBuilder<T>();
+        }
+
+        /// <inheritdoc/>
+        protected override ImmutableHashSet<T> FinalizeResult(object accumulator)
+        {
+            return ((ImmutableHashSet<T>.Builder)accumulator).ToImmutable();
+        }
+    }
+}
+#endif

src/MongoDB.Bson/Serialization/Serializers/ImmutableListSerializer.cs

@@ -0,0 +1,40 @@
+/* Copyright 2010-present MongoDB Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#if NET6_0_OR_GREATER
+using System.Collections.Immutable;
+
+namespace MongoDB.Bson.Serialization.Serializers
+{
+    /// <summary>
+    /// Represents a serializer for ImmutableLists.
+    /// </summary>
+    /// <typeparam name="T">The type of element stored by the collection.</typeparam>
+    public class ImmutableListSerializer<T>: EnumerableInterfaceImplementerSerializerBase<ImmutableList<T>, T>
+    {
+        /// <inheritdoc/>
+        protected override object CreateAccumulator()
+        {
+            return ImmutableList.CreateBuilder<T>();
+        }
+
+        /// <inheritdoc/>
+        protected override ImmutableList<T> FinalizeResult(object accumulator)
+        {
+            return ((ImmutableList<T>.Builder)accumulator).ToImmutable();
+        }
+    }
+}
+#endif

src/MongoDB.Bson/Serialization/Serializers/ImmutableQueueSerializer.cs

@@ -0,0 +1,41 @@
+/* Copyright 2010-present MongoDB Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#if NET6_0_OR_GREATER
+using System.Collections.Generic;
+using System.Collections.Immutable;
+
+namespace MongoDB.Bson.Serialization.Serializers
+{
+    /// <summary>
+    /// Represents a serializer for ImmutableQueues.
+    /// </summary>
+    /// <typeparam name="T">The type of element stored by the collection.</typeparam>
+    public class ImmutableQueueSerializer<T>: EnumerableInterfaceImplementerSerializerBase<ImmutableQueue<T>, T>
+    {
+        /// <inheritdoc/>
+        protected override object CreateAccumulator()
+        {
+            return new List<T>();
+        }
+
+        /// <inheritdoc/>
+        protected override ImmutableQueue<T> FinalizeResult(object accumulator)
+        {
+            return ImmutableQueue.CreateRange((List<T>)accumulator);
+        }
+    }
+}
+#endif

src/MongoDB.Bson/Serialization/Serializers/ImmutableSortedDictionarySerializer.cs

@@ -0,0 +1,42 @@
+/* Copyright 2010-present MongoDB Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#if NET6_0_OR_GREATER
+using System.Collections.Generic;
+using System.Collections.Immutable;
+
+namespace MongoDB.Bson.Serialization.Serializers
+{
+    /// <summary>
+    /// Represents a serializer for ImmutableSortedDictionaries.
+    /// </summary>
+    /// <typeparam name="TKey">The type of the keys in the dictionary.</typeparam>
+    /// <typeparam name="TValue">The type of the values in the dictionary.</typeparam>
+    public class ImmutableSortedDictionarySerializer<TKey, TValue>: DictionaryInterfaceImplementerSerializer<ImmutableSortedDictionary<TKey, TValue>, TKey, TValue>
+    {
+        /// <inheritdoc/>
+        protected override ICollection<KeyValuePair<TKey, TValue>> CreateAccumulator()
+        {
+            return ImmutableSortedDictionary.CreateBuilder<TKey, TValue>();
+        }
+
+        /// <inheritdoc/>
+        protected override ImmutableSortedDictionary<TKey, TValue> FinalizeAccumulator(ICollection<KeyValuePair<TKey, TValue>> accumulator)
+        {
+            return ((ImmutableSortedDictionary<TKey, TValue>.Builder)accumulator).ToImmutable();
+        }
+    }
+}
+#endif