- PR comments

Author: BorisDog

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

@@ -152,8 +152,8 @@ public TClass DeserializeClass(BsonDeserializationContext context)
             var allMemberMaps = _classMap.AllMemberMaps;
             var extraElementsMemberMapIndex = _classMap.ExtraElementsMemberMapIndex;
 
-            var (bitArrayLength, useStackAlloc) = FastMemberMapHelper.GetBitArrayLength(_classMap.AllMemberMaps.Count);
-            using var bitArray = useStackAlloc ? FastMemberMapHelper.GetBitArray(stackalloc uint[bitArrayLength]) : FastMemberMapHelper.GetBitArray(bitArrayLength);
+            var (bitArrayLength, useStackAlloc) = FastMemberMapHelper.GetMembersBitArrayLength(_classMap.AllMemberMaps.Count);
+            using var bitArray = useStackAlloc ? FastMemberMapHelper.GetMembersBitArray(stackalloc uint[bitArrayLength]) : FastMemberMapHelper.GetMembersBitArray(bitArrayLength);
 
             bsonReader.ReadStartDocument();
             var elementTrie = _classMap.ElementTrie;
@@ -686,25 +686,29 @@ private bool ShouldSerializeDiscriminator(Type nominalType)
         // helper class that implements member map bit array helper functions
         internal static class FastMemberMapHelper
         {
-            internal ref struct BitArray()
+            internal ref struct MembersBitArray()
             {
                 private readonly ArrayPool<uint> _arrayPool;
                 private readonly Span<uint> _bitArray;
                 private readonly uint[] _rentedBuffer;
                 private bool _isDisposed = false;
 
-                public BitArray(Span<uint> bitArray) : this()
+                public MembersBitArray(Span<uint> bitArray) : this()
                 {
                     _arrayPool = null;
                     _bitArray = bitArray;
                     _rentedBuffer = null;
+
+                    _bitArray.Clear();
                 }
 
-                public BitArray(int spanLength, uint[] rentedBuffer, ArrayPool<uint> arrayPool) : this()
+                public MembersBitArray(int spanLength, uint[] rentedBuffer, ArrayPool<uint> arrayPool) : this()
                 {
                     _arrayPool = arrayPool;
                     _bitArray = rentedBuffer.AsSpan(0, spanLength);
                     _rentedBuffer = rentedBuffer;
+
+                    _bitArray.Clear();
                 }
 
                 public Span<uint> Span => _bitArray;
@@ -726,32 +730,17 @@ public void Dispose()
                 }
             }
 
-            public static (int BitArrayLength, bool UseStackAlloc) GetBitArrayLength(int membersCount)
+            public static (int BitArrayLength, bool UseStackAlloc) GetMembersBitArrayLength(int membersCount)
             {
                 var length = (membersCount + 31) >> 5;
                 return (length, length <= 8); // Use stackalloc for up to 256 members
             }
 
-            public static BitArray GetBitArray(Span<uint> span) =>
-                new(ResetSpan(span));
-
-            public static BitArray GetBitArray(int length)
-            {
-                var rentedBuffer = ArrayPool<uint>.Shared.Rent(length);
-                ResetSpan(rentedBuffer);
-
-                return new(length, rentedBuffer, ArrayPool<uint>.Shared);
-            }
+            public static MembersBitArray GetMembersBitArray(Span<uint> span) =>
+                new(span);
 
-            private static Span<uint> ResetSpan(Span<uint> span)
-            {
-                for (var i = 0; i < span.Length; i++)
-                {
-                    span[i] = 0;
-                }
-
-                return span;
-            }
+            public static MembersBitArray GetMembersBitArray(int length) =>
+                new(length, ArrayPool<uint>.Shared.Rent(length), ArrayPool<uint>.Shared);
         }
     }
 }

tests/MongoDB.Bson.Tests/Serialization/BsonClassMapSerializerTests.cs

@@ -85,7 +85,7 @@ public void Deserialize_should_not_throw_when_all_required_elements_present(
         [InlineData(1024, 993)]
         [InlineData(1024, 1000)]
         [InlineData(1024, 1023)]
-        public void Deserialize_should_throw_FormatException_when_no_required_element_is_found(int membersCount, int missingMemberIndex)
+        public void Deserialize_should_throw_FormatException_when_required_element_is_not_found(int membersCount, int missingMemberIndex)
         {
             var subject = BuildTypeAndGetSerializer("Prop", membersCount);
             var properties = Enumerable
@@ -197,19 +197,19 @@ public void Equals_with_not_equal_field_should_return_false()
         [InlineData(33, 2, true)]
         [InlineData(256, 8, true)]
         [InlineData(257, 9, false)]
-        public void FastMemberMapHelper_GetBitArrayLength_should_return_correctValue(int memberCount, int expectedBitArrayLength, bool expectedUseStackAlloc)
+        public void FastMemberMapHelper_GetMembersBitArrayLength_should_return_correctValue(int memberCount, int expectedBitArrayLength, bool expectedUseStackAlloc)
         {
-            var (bitArrayLength, useStackAlloc) = BsonClassMapSerializer<MyModel>.FastMemberMapHelper.GetBitArrayLength(memberCount);
+            var (bitArrayLength, useStackAlloc) = BsonClassMapSerializer<MyModel>.FastMemberMapHelper.GetMembersBitArrayLength(memberCount);
 
             bitArrayLength.ShouldBeEquivalentTo(expectedBitArrayLength);
             useStackAlloc.ShouldBeEquivalentTo(expectedUseStackAlloc);
         }
 
         [Fact]
-        public void FastMemberMapHelper_GetBitArray_with_span_should_use_the_provided_span()
+        public void FastMemberMapHelper_GetMembersBitArray_with_span_should_use_the_provided_span()
         {
             var backingArray = new uint[] { 1, 2, 3 };
-            using var bitArray =  BsonClassMapSerializer<MyModel>.FastMemberMapHelper.GetBitArray(backingArray);
+            using var bitArray =  BsonClassMapSerializer<MyModel>.FastMemberMapHelper.GetMembersBitArray(backingArray);
 
             bitArray.Span.ToArray().ShouldBeEquivalentTo(new uint[] { 0, 0, 0 });
             bitArray.ArrayPool.Should().Be(null);
@@ -221,9 +221,9 @@ public void FastMemberMapHelper_GetBitArray_with_span_should_use_the_provided_sp
         [Theory]
         [InlineData(3)]
         [InlineData(25)]
-        public void FastMemberMapHelper_GetBitArray_with_length_should_allocate_span(int length)
+        public void FastMemberMapHelper_GetMembersBitArray_with_length_should_allocate_span(int length)
         {
-            using var bitArray = BsonClassMapSerializer<MyModel>.FastMemberMapHelper.GetBitArray(length);
+            using var bitArray = BsonClassMapSerializer<MyModel>.FastMemberMapHelper.GetMembersBitArray(length);
 
             bitArray.Span.ToArray().ShouldBeEquivalentTo(Enumerable.Repeat<uint>(0, length));
             bitArray.ArrayPool.Should().Be(ArrayPool<uint>.Shared);
@@ -232,12 +232,12 @@ public void FastMemberMapHelper_GetBitArray_with_length_should_allocate_span(int
         [Theory]
         [InlineData(1)]
         [InlineData(2)]
-        public void FastMemberMapHelper_BitArray_with_arraypool_should_dispose_only_once(int disposeCount)
+        public void FastMemberMapHelper_MembersBitArray_with_arraypool_should_dispose_only_once(int disposeCount)
         {
             var backingArray = new uint[] { 1, 2, 3 };
 
             var mockArrayPool = new Mock<ArrayPool<uint>>();
-            var bitArray = new BsonClassMapSerializer<MyModel>.FastMemberMapHelper.BitArray(backingArray.Length, backingArray, mockArrayPool.Object);
+            var bitArray = new BsonClassMapSerializer<MyModel>.FastMemberMapHelper.MembersBitArray(backingArray.Length, backingArray, mockArrayPool.Object);
 
             for (int i = 0; i < disposeCount; i++)
             {
@@ -255,10 +255,10 @@ public void FastMemberMapHelper_BitArray_with_arraypool_should_dispose_only_once
         [InlineData(266, 255)]
         [InlineData(544, 0)]
         [InlineData(621, 255)]
-        public void FastMemberMapHelper_GetBitArray_SetMemberIndex_should_set_correct_bit(int membersCount, int memberIndex)
+        public void FastMemberMapHelper_GetMembersBitArray_SetMemberIndex_should_set_correct_bit(int membersCount, int memberIndex)
         {
-            var (length, _) = BsonClassMapSerializer<MyModel>.FastMemberMapHelper.GetBitArrayLength(membersCount);
-            using var bitArray = BsonClassMapSerializer<MyModel>.FastMemberMapHelper.GetBitArray(length);
+            var (length, _) = BsonClassMapSerializer<MyModel>.FastMemberMapHelper.GetMembersBitArrayLength(membersCount);
+            using var bitArray = BsonClassMapSerializer<MyModel>.FastMemberMapHelper.GetMembersBitArray(length);
 
             var span = bitArray.Span;
             var blockIndex = memberIndex >> 5;