Fix: Linux Interop Issues for Custom Merge Operators

.gitignore

@@ -287,3 +287,4 @@ __pycache__/
 *.btm.cs
 *.odx.cs
 *.xsd.cs
+.DS_Store

Tests/CustomMergeOperatorTests.cs

@@ -0,0 +1,65 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using System.Text;
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+using RocksDbSharp;
+
+namespace Tests;
+
+[TestClass]
+public class CustomMergeOperatorTests
+{
+    [TestMethod]
+    public void CustomMergeOperatorAppendsMultipleValues()
+    {
+        var mergeOp = MergeOperators.Create(
+            "StringAppend",
+            (ReadOnlySpan<byte> key, MergeOperators.OperandsEnumerator operands, out bool success) =>
+            {
+                var result = new List<byte>();
+                for (int i = 0; i < operands.Count; i++)
+                {
+                    result.AddRange(operands.Get(i).ToArray());
+                }
+                success = true;
+                return result.ToArray();
+            },
+            (ReadOnlySpan<byte> key, bool hasExisting, ReadOnlySpan<byte> existing,
+                MergeOperators.OperandsEnumerator operands, out bool success) =>
+            {
+                var result = hasExisting ? existing.ToArray().ToList() : new List<byte>();
+                for (int i = 0; i < operands.Count; i++)
+                {
+                    result.AddRange(operands.Get(i).ToArray());
+                }
+                success = true;
+                return result.ToArray();
+            });
+
+        var opts = new ColumnFamilyOptions().SetMergeOperator(mergeOp);
+        var dbPath = Path.Combine(Path.GetTempPath(), Guid.NewGuid().ToString());
+        try
+        {
+            using var db = RocksDb.Open(new DbOptions().SetCreateIfMissing(),
+                dbPath,
+                new ColumnFamilies(opts));
+
+            db.Merge("key"u8.ToArray(), "hello"u8.ToArray());
+            db.Merge("key"u8.ToArray(), "world"u8.ToArray());
+
+            var value = db.Get("key"u8.ToArray());
+
+            Assert.IsNotNull(value);
+            Assert.AreEqual("helloworld", Encoding.UTF8.GetString(value));
+        }
+        finally
+        {
+            if (Directory.Exists(dbPath))
+            {
+                Directory.Delete(dbPath, recursive: true);
+            }
+        }
+    }
+}

build-codegen/Generate.cs

@@ -86,15 +86,15 @@ private static string ManualEnumName(NativeEnum nativeEnum)
             }
             if (funcName == "rocksdb_mergeoperator_create_full_merge" && arg.Name == "success")
             {
-                yield return ("out unsigned_char_ptr", "default");
+                yield return ("out byte", "default");
             }
             if (funcName == "rocksdb_mergeoperator_create_full_merge" && arg.Name == "new_value_length")
             {
                 yield return ("out size_t_ptr", "default");
             }
             if (funcName == "rocksdb_mergeoperator_create_partial_merge" && arg.Name == "success")
             {
-                yield return ("out unsigned_char_ptr", "default");
+                yield return ("out byte", "default");
             }
             if (funcName == "rocksdb_mergeoperator_create_partial_merge" && arg.Name == "new_value_length")
             {

csharp/src/MergeOperator.cs

@@ -8,8 +8,8 @@ namespace RocksDbSharp
     public interface MergeOperator
     {
         string Name { get; }
-        IntPtr PartialMerge(IntPtr key, UIntPtr keyLength, IntPtr operandsList, IntPtr operandsListLength, int numOperands, out IntPtr success, out IntPtr newValueLength);
-        IntPtr FullMerge(IntPtr key, UIntPtr keyLength, IntPtr existingValue, UIntPtr existingValueLength, IntPtr operandsList, IntPtr operandsListLength, int numOperands, out IntPtr success, out IntPtr newValueLength);
+        IntPtr PartialMerge(IntPtr key, UIntPtr keyLength, IntPtr operandsList, IntPtr operandsListLength, int numOperands, out byte success, out IntPtr newValueLength);
+        IntPtr FullMerge(IntPtr key, UIntPtr keyLength, IntPtr existingValue, UIntPtr existingValueLength, IntPtr operandsList, IntPtr operandsListLength, int numOperands, out byte success, out IntPtr newValueLength);
         void DeleteValue(IntPtr value, UIntPtr valueLength);
     }
 
@@ -81,7 +81,7 @@ public MergeOperatorImpl(string name, PartialMergeFunc partialMerge, FullMergeFu
                 FullMerge = fullMerge;
             }
 
-            unsafe IntPtr MergeOperator.PartialMerge(IntPtr key, UIntPtr keyLength, IntPtr operandsList, IntPtr operandsListLength, int numOperands, out IntPtr success, out IntPtr newValueLength)
+            unsafe IntPtr MergeOperator.PartialMerge(IntPtr key, UIntPtr keyLength, IntPtr operandsList, IntPtr operandsListLength, int numOperands, out byte success, out IntPtr newValueLength)
             {
                 var keySpan                = new ReadOnlySpan<byte>((void*)key, (int)keyLength);
                 var operandsListSpan       = new ReadOnlySpan<IntPtr>((void*)operandsList, numOperands);
@@ -94,12 +94,12 @@ unsafe IntPtr MergeOperator.PartialMerge(IntPtr key, UIntPtr keyLength, IntPtr o
                 Marshal.Copy(value, 0, ret, value.Length);
                 newValueLength = (IntPtr)value.Length;
 
-                success = (IntPtr)Convert.ToInt32(_success);
+                success = (byte)(_success ? 1 : 0);
 
                 return ret;
             }
 
-            unsafe IntPtr MergeOperator.FullMerge(IntPtr key, UIntPtr keyLength, IntPtr existingValue, UIntPtr existingValueLength, IntPtr operandsList, IntPtr operandsListLength, int numOperands, out IntPtr success, out IntPtr newValueLength)
+            unsafe IntPtr MergeOperator.FullMerge(IntPtr key, UIntPtr keyLength, IntPtr existingValue, UIntPtr existingValueLength, IntPtr operandsList, IntPtr operandsListLength, int numOperands, out byte success, out IntPtr newValueLength)
             {
                 var keySpan                = new ReadOnlySpan<byte>((void*)key, (int)keyLength);
                 var operandsListSpan       = new ReadOnlySpan<IntPtr>((void*)operandsList, numOperands);
@@ -114,7 +114,7 @@ unsafe IntPtr MergeOperator.FullMerge(IntPtr key, UIntPtr keyLength, IntPtr exis
                 Marshal.Copy(value, 0, ret, value.Length);
                 newValueLength = (IntPtr)value.Length;
 
-                success = (IntPtr)Convert.ToInt32(_success);
+                success = (byte)(_success ? 1 : 0);
 
                 return ret;
             }

csharp/src/Native.cs

@@ -145,8 +145,8 @@ namespace RocksDbSharp
     public delegate int CompareDelegate(void_ptr p0, const_char_ptr a, size_t alen, const_char_ptr b, size_t blen);
     public delegate int CompareTsDelegate(void_ptr p0, const_char_ptr a_ts, size_t a_tslen, const_char_ptr b_ts, size_t b_tslen);
     public delegate int CompareWithoutTsDelegate(void_ptr p0, const_char_ptr a, size_t alen, bool a_has_ts, const_char_ptr b, size_t blen, bool b_has_ts);
-    public delegate char_ptr FullMergeDelegate(void_ptr p0, const_char_ptr key, size_t key_length, const_char_ptr existing_value, size_t existing_value_length, const_char_ptr_const_ptr operands_list, const_size_t_ptr operands_list_length, int num_operands, out unsigned_char_ptr success, out size_t_ptr new_value_length);
-    public delegate char_ptr PartialMergeDelegate(void_ptr p0, const_char_ptr key, size_t key_length, const_char_ptr_const_ptr operands_list, const_size_t_ptr operands_list_length, int num_operands, out unsigned_char_ptr success, out size_t_ptr new_value_length);
+    public delegate char_ptr FullMergeDelegate(void_ptr p0, const_char_ptr key, size_t key_length, const_char_ptr existing_value, size_t existing_value_length, const_char_ptr_const_ptr operands_list, const_size_t_ptr operands_list_length, int num_operands, out byte success, out size_t_ptr new_value_length);
+    public delegate char_ptr PartialMergeDelegate(void_ptr p0, const_char_ptr key, size_t key_length, const_char_ptr_const_ptr operands_list, const_size_t_ptr operands_list_length, int num_operands, out byte success, out size_t_ptr new_value_length);
     public delegate void DeleteValueDelegate(void_ptr p0, const_char_ptr value, size_t value_length);
     public delegate char_ptr TransformDelegate(void_ptr p0, const_char_ptr key, size_t length, size_t_ptr dst_length);
     public delegate char InDomainDelegate(void_ptr p0, const_char_ptr key, size_t length);

csharp/src/Options/ColumnFamilyOptions.cs

@@ -323,13 +323,13 @@ private static MergeOperator GetMergeOperatorFromPtr(IntPtr getMergeOperatorPtr)
             return getMergeOperator();
         }
 
-        private unsafe static IntPtr MergeOperator_PartialMerge(IntPtr state, IntPtr key, UIntPtr keyLength, IntPtr operandsList, IntPtr operandsListLength, int numOperands, out IntPtr success, out IntPtr newValueLength)
+        private unsafe static IntPtr MergeOperator_PartialMerge(IntPtr state, IntPtr key, UIntPtr keyLength, IntPtr operandsList, IntPtr operandsListLength, int numOperands, out byte success, out IntPtr newValueLength)
         {
             var mergeOperator = GetMergeOperatorFromPtr((*((OptionsBase.MergeOperatorState*)state)).GetMergeOperatorPtr);
             return mergeOperator.PartialMerge(key, keyLength, operandsList, operandsListLength, numOperands, out success, out newValueLength);
         }
 
-        private unsafe static IntPtr MergeOperator_FullMerge(IntPtr state, IntPtr key, UIntPtr keyLength, IntPtr existingValue, UIntPtr existingValueLength, IntPtr operandsList, IntPtr operandsListLength, int numOperands, out IntPtr success, out IntPtr newValueLength)
+        private unsafe static IntPtr MergeOperator_FullMerge(IntPtr state, IntPtr key, UIntPtr keyLength, IntPtr existingValue, UIntPtr existingValueLength, IntPtr operandsList, IntPtr operandsListLength, int numOperands, out byte success, out IntPtr newValueLength)
         {
             var mergeOperator = GetMergeOperatorFromPtr((*((OptionsBase.MergeOperatorState*)state)).GetMergeOperatorPtr);
             return mergeOperator.FullMerge(key, keyLength, existingValue, existingValueLength, operandsList, operandsListLength, numOperands, out success, out newValueLength);