Merge branch 'master' into HF_Echidna

.devcontainer/devcontainer.dockerfile

@@ -1,6 +1,6 @@
 # https://github.com/dotnet/dotnet-docker/blob/main/README.sdk.md
 # https://mcr.microsoft.com/en-us/artifact/mar/dotnet/sdk/tags <-- this shows all images
-FROM mcr.microsoft.com/dotnet/sdk:9.0.101-noble
+FROM mcr.microsoft.com/dotnet/sdk:9.0.102-noble
 
 # Install the libleveldb-dev package 
 RUN apt-get update && apt-get install -y libleveldb-dev

benchmarks/Directory.Build.props

@@ -2,6 +2,7 @@
 <Project ToolsVersion="15.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
 
   <PropertyGroup>
+    <LangVersion>latest</LangVersion>
     <IsPackable>false</IsPackable>
   </PropertyGroup>
 

benchmarks/Neo.Benchmarks/Persistence/Bechmarks_LevelDB.cs

@@ -0,0 +1,59 @@
+// Copyright (C) 2015-2025 The Neo Project.
+//
+// Bechmarks_LevelDB.cs file belongs to the neo project and is free
+// software distributed under the MIT software license, see the
+// accompanying file LICENSE in the main directory of the
+// repository or http://www.opensource.org/licenses/mit-license.php
+// for more details.
+//
+// Redistribution and use in source and binary forms with or without
+// modifications are permitted.
+
+using BenchmarkDotNet.Attributes;
+using Neo.Persistence;
+using Neo.Plugins.Storage;
+using Neo.SmartContract;
+using System.Diagnostics;
+
+namespace Neo.Benchmarks.Persistence.Benchmarks
+{
+    public class Bechmarks_LevelDB
+    {
+        // avoid allocations in benchmarks
+        private static StorageKey key1;
+        private static readonly byte[] value = new UInt256().GetSpan().ToArray();
+
+        private const string PathLevelDB = "Data_LevelDB_Benchmarks";
+
+        private static readonly LevelDBStore levelDb = new();
+        private static ISnapshot snapshot;
+
+        [GlobalSetup]
+        public void Setup()
+        {
+            if (Directory.Exists(PathLevelDB))
+                Directory.Delete(PathLevelDB, true);
+
+            key1 = new KeyBuilder(1, 1).Add(new UInt160());
+
+            var levelDbStore = levelDb.GetStore(PathLevelDB);
+            snapshot = levelDbStore.GetSnapshot();
+        }
+
+        [GlobalCleanup]
+        public void Cleanup()
+        {
+            snapshot.Dispose();
+            levelDb.Dispose();
+            if (Directory.Exists(PathLevelDB))
+                Directory.Delete(PathLevelDB, true);
+        }
+
+        [Benchmark]
+        public void LevelDBSnapshotWrites()
+        {
+            snapshot.Put(key1.ToArray(), value);
+            snapshot.Delete(key1.ToArray());
+        }
+    }
+}

benchmarks/Neo.Benchmarks/Program.cs

@@ -19,3 +19,4 @@
 BenchmarkRunner.Run<Benchmarks_Hash>();
 BenchmarkRunner.Run<Benchmarks_StorageKey>();
 BenchmarkRunner.Run<Bechmarks_ReadOnlyStoreView>();
+BenchmarkRunner.Run<Bechmarks_LevelDB>();

global.json

@@ -1,6 +1,6 @@
 {
   "sdk": {
-    "version": "9.0.100",
+    "version": "9.0.102",
     "rollForward": "latestFeature",
     "allowPrerelease": false
   }

src/Neo/Persistence/MemorySnapshot.cs

@@ -20,6 +20,9 @@
 
 namespace Neo.Persistence
 {
+    /// <summary>
+    /// <remarks>On-chain write operations on a snapshot cannot be concurrent.</remarks>
+    /// </summary>
     internal class MemorySnapshot : ISnapshot
     {
         private readonly ConcurrentDictionary<byte[], byte[]> _innerData;
@@ -47,9 +50,7 @@ public void Delete(byte[] key)
             _writeBatch[key] = null;
         }
 
-        public void Dispose()
-        {
-        }
+        public void Dispose() { }
 
         public void Put(byte[] key, byte[] value)
         {

src/Plugins/LevelDBStore/Plugins/Storage/Snapshot.cs

@@ -19,14 +19,20 @@ namespace Neo.Plugins.Storage
 {
     /// <summary>
     /// <code>Iterating over the whole dataset can be time-consuming. Depending upon how large the dataset is.</code>
+    /// <remarks>On-chain write operations on a snapshot cannot be concurrent.</remarks>
     /// </summary>
     internal class Snapshot : ISnapshot, IEnumerable<KeyValuePair<byte[], byte[]>>
     {
         private readonly DB _db;
         private readonly LSnapshot _snapshot;
         private readonly ReadOptions _readOptions;
         private readonly WriteBatch _batch;
+
+#if NET9_0_OR_GREATER
+        private readonly System.Threading.Lock _lock = new();
+#else
         private readonly object _lock = new();
+#endif
 
         public Snapshot(DB db)
         {
@@ -36,18 +42,27 @@ public Snapshot(DB db)
             _batch = new WriteBatch();
         }
 
+        /// <inheritdoc/>
         public void Commit()
         {
             lock (_lock)
                 _db.Write(WriteOptions.Default, _batch);
         }
 
+        /// <inheritdoc/>
         public void Delete(byte[] key)
         {
             lock (_lock)
                 _batch.Delete(key);
         }
 
+        /// <inheritdoc/>
+        public void Put(byte[] key, byte[] value)
+        {
+            lock (_lock)
+                _batch.Put(key, value);
+        }
+
         public void Dispose()
         {
             _snapshot.Dispose();
@@ -60,12 +75,6 @@ public void Dispose()
             return _db.Seek(_readOptions, keyOrPrefix, direction);
         }
 
-        public void Put(byte[] key, byte[] value)
-        {
-            lock (_lock)
-                _batch.Put(key, value);
-        }
-
         public bool Contains(byte[] key)
         {
             return _db.Contains(_readOptions, key);

src/Plugins/RocksDBStore/Plugins/Storage/Snapshot.cs

@@ -16,6 +16,9 @@
 
 namespace Neo.Plugins.Storage
 {
+    /// <summary>
+    /// <remarks>On-chain write operations on a snapshot cannot be concurrent.</remarks>
+    /// </summary>
     internal class Snapshot : ISnapshot
     {
         private readonly RocksDb db;

tests/Directory.Build.props

@@ -2,7 +2,7 @@
 <Project ToolsVersion="15.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
 
   <PropertyGroup>
-    <LangVersion>12.0</LangVersion>
+    <LangVersion>latest</LangVersion>
     <EnforceCodeStyleInBuild>false</EnforceCodeStyleInBuild>
     <IsPackable>false</IsPackable>
     <IsTestProject>true</IsTestProject>