Add Memory-based binary converters (AllocZero#242)

* Add Memory-based binary converters * Update converters section in docs.
devtekve · May 11, 2024 · dd8ec28 · dd8ec28
1 parent a52c374
commit dd8ec28
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Showing 7 changed files with 86 additions and 3 deletions.
diff --git a/src/EfficientDynamoDb/Converters/DdbWriter.cs b/src/EfficientDynamoDb/Converters/DdbWriter.cs
@@ -1,3 +1,4 @@
+using System;
 using System.Runtime.CompilerServices;
 using System.Text.Json;
 using System.Threading.Tasks;
@@ -47,7 +48,7 @@ public void WriteDdbBool(bool value)
         }
 
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public void WriteDdbBinary(byte[] value)
+        public void WriteDdbBinary(ReadOnlySpan<byte> value)
         {
             JsonWriter.WriteStartObject();
             JsonWriter.WriteBase64String(DdbTypeNames.Binary, value);

diff --git a/src/EfficientDynamoDb/DynamoDbContextMetadata.cs b/src/EfficientDynamoDb/DynamoDbContextMetadata.cs
@@ -10,6 +10,7 @@
 using EfficientDynamoDb.Internal.Converters.Collections;
 using EfficientDynamoDb.Internal.Converters.Documents;
 using EfficientDynamoDb.Internal.Converters.Primitives;
+using EfficientDynamoDb.Internal.Converters.Primitives.Binary;
 using EfficientDynamoDb.Internal.Metadata;
 
 namespace EfficientDynamoDb
@@ -22,7 +23,8 @@ public class DynamoDbContextMetadata
             new DictionaryDdbConverterFactory(), new IDictionaryDdbConverterFactory(), new IReadOnlyDictionaryDdbConverterFactory(),
             new NumberSetDdbConverterFactory(), new NumberISetDdbConverterFactory(), new StringSetDdbConverterFactory(), new StringISetDdbConverterFactory(),
             new IReadOnlyCollectionDdbConverterFactory(), new IReadOnlyListDdbConverterFactory(), new IListDdbConverterFactory(),
-            new DocumentDdbConverterFactory(), new AttributeValueDdbConverterFactory(), new BinaryDdbConverterFactory(), new ArrayDdbConverterFactory()
+            new DocumentDdbConverterFactory(), new AttributeValueDdbConverterFactory(), new BinaryDdbConverterFactory(), new ArrayDdbConverterFactory(),
+            new BinaryToMemoryDdbConverterFactory(), new BinaryToReadOnlyMemoryDdbConverterFactory(),
         };
 
         private readonly IReadOnlyCollection<DdbConverter> _converters;

diff --git a/...nverters/Primitives/BinaryDdbConverter.cs → ...s/Primitives/Binary/BinaryDdbConverter.cs b/...nverters/Primitives/BinaryDdbConverter.cs → ...s/Primitives/Binary/BinaryDdbConverter.cs
@@ -2,7 +2,7 @@
 using EfficientDynamoDb.Converters;
 using EfficientDynamoDb.DocumentModel;
 
-namespace EfficientDynamoDb.Internal.Converters.Primitives
+namespace EfficientDynamoDb.Internal.Converters.Primitives.Binary
 {
     internal sealed class BinaryDdbConverter : DdbConverter<byte[]?>
     {

diff --git a/src/EfficientDynamoDb/Internal/Converters/Primitives/Binary/BinaryToMemoryDdbConverter.cs b/src/EfficientDynamoDb/Internal/Converters/Primitives/Binary/BinaryToMemoryDdbConverter.cs
@@ -0,0 +1,39 @@
+using System;
+using System.Diagnostics;
+using System.Runtime.InteropServices;
+using EfficientDynamoDb.Converters;
+using EfficientDynamoDb.DocumentModel;
+
+namespace EfficientDynamoDb.Internal.Converters.Primitives.Binary
+{
+    internal sealed class BinaryToMemoryDdbConverter : DdbConverter<Memory<byte>>
+    {
+        public override Memory<byte> Read(in AttributeValue attributeValue) => 
+            attributeValue.AsBinaryAttribute().Value;
+
+        public override AttributeValue Write(ref Memory<byte> value)
+        {
+            var array = MemoryMarshal.TryGetArray((ReadOnlyMemory<byte>)value, out var segment)
+                ? segment.Array
+                : value.ToArray();
+            Debug.Assert(array != null);
+
+            return new AttributeValue(new BinaryAttributeValue(array));
+        }
+
+        public override Memory<byte> Read(ref DdbReader reader) => 
+            reader.JsonReaderValue.GetBytesFromBase64();
+
+        public override void Write(in DdbWriter writer, ref Memory<byte> value) => 
+            writer.WriteDdbBinary(value.Span);
+    }
+
+    internal sealed class BinaryToMemoryDdbConverterFactory : DdbConverterFactory
+    {
+        public override bool CanConvert(Type typeToConvert) =>
+            typeToConvert == typeof(Memory<byte>) || typeToConvert == typeof(Memory<byte>?);
+
+        public override DdbConverter CreateConverter(Type typeToConvert, DynamoDbContextMetadata metadata) => 
+            new BinaryToMemoryDdbConverter();
+    }
+}
diff --git a/...cientDynamoDb/Internal/Converters/Primitives/Binary/BinaryToReadOnlyMemoryDdbConverter.cs b/...cientDynamoDb/Internal/Converters/Primitives/Binary/BinaryToReadOnlyMemoryDdbConverter.cs
@@ -0,0 +1,39 @@
+using System;
+using System.Diagnostics;
+using System.Runtime.InteropServices;
+using EfficientDynamoDb.Converters;
+using EfficientDynamoDb.DocumentModel;
+
+namespace EfficientDynamoDb.Internal.Converters.Primitives.Binary
+{
+    internal sealed class BinaryToReadOnlyMemoryDdbConverter : DdbConverter<ReadOnlyMemory<byte>>
+    {
+        public override ReadOnlyMemory<byte> Read(in AttributeValue attributeValue) => 
+            attributeValue.AsBinaryAttribute().Value;
+
+        public override AttributeValue Write(ref ReadOnlyMemory<byte> value)
+        {
+            var array = MemoryMarshal.TryGetArray(value, out var segment)
+                ? segment.Array
+                : value.ToArray();
+            Debug.Assert(array != null);
+
+            return new AttributeValue(new BinaryAttributeValue(array));
+        }
+
+        public override ReadOnlyMemory<byte> Read(ref DdbReader reader) => 
+            reader.JsonReaderValue.GetBytesFromBase64();
+
+        public override void Write(in DdbWriter writer, ref ReadOnlyMemory<byte> value) => 
+            writer.WriteDdbBinary(value.Span);
+    }
+
+    internal sealed class BinaryToReadOnlyMemoryDdbConverterFactory : DdbConverterFactory
+    {
+        public override bool CanConvert(Type typeToConvert) => 
+            typeToConvert == typeof(ReadOnlyMemory<byte>) || typeToConvert == typeof(ReadOnlyMemory<byte>?);
+
+        public override DdbConverter CreateConverter(Type typeToConvert, DynamoDbContextMetadata metadata) => 
+            new BinaryToReadOnlyMemoryDdbConverter();
+    }
+}
diff --git a/src/EfficientDynamoDb/Internal/Metadata/DefaultDdbConverterFactory.cs b/src/EfficientDynamoDb/Internal/Metadata/DefaultDdbConverterFactory.cs
@@ -7,6 +7,7 @@
 using EfficientDynamoDb.Exceptions;
 using EfficientDynamoDb.Internal.Converters.Collections.BinarySet;
 using EfficientDynamoDb.Internal.Converters.Primitives;
+using EfficientDynamoDb.Internal.Converters.Primitives.Binary;
 using EfficientDynamoDb.Internal.Converters.Primitives.Enums;
 using EfficientDynamoDb.Internal.Converters.Primitives.Numbers;
 

diff --git a/website/docs/dev_guide/high_level/converters.md b/website/docs/dev_guide/high_level/converters.md
@@ -20,6 +20,7 @@ EfficientDynamoDb does not require specifying a converter explicitly for the fol
 * Guids
 * Booleans
 * Collections: arrays, lists, dictionaries, sets (including their read-only and mutable interfaces)
+* Binary data: `byte[]`, `Memory<byte>`, `ReadOnlyMemory<byte>`
 * `AttributeValue` structs (low-level API representation of the DynamoDB attribute)
 
 In addition, you can use one of the following converters to change the default behavior: