Various fixes for scripting runtime

Development/Documentation/mono.md

@@ -2,6 +2,8 @@
 
 Custom fork: [https://github.com/FlaxEngine/mono](https://github.com/FlaxEngine/mono) with custom features for C# assemblies hot-reloading at runtime without domain unload (more: [https://flaxengine.com/blog/flax-facts-16-scripts-hot-reload/](https://flaxengine.com/blog/flax-facts-16-scripts-hot-reload/)).
 
+Startup docs about building mono: [https://www.mono-project.com/docs/compiling-mono/](https://www.mono-project.com/docs/compiling-mono/)
+
 ### Notes
 
 Some useful notes and tips for devs:

Source/Engine/Content/JsonAsset.cpp

@@ -281,9 +281,10 @@ bool JsonAsset::CreateInstance()
 
 void JsonAsset::DeleteInstance()
 {
-    ASSERT_LOW_LAYER(Instance && _dtor);
+    if (!Instance || !_dtor)
-    InstanceType = ScriptingTypeHandle();
+        return;
     _dtor(Instance);
+    InstanceType = ScriptingTypeHandle();
     Allocator::Free(Instance);
     Instance = nullptr;
     _dtor = nullptr;

Source/Engine/Scripting/BinaryModule.h

@@ -260,7 +260,7 @@ public:
 
 private:
 
-    int32 _firstManagedTypeIndex;
+    int32 _firstManagedTypeIndex = 0;
     Array<void*> _managedMemoryBlocks;
 
 public:

Source/Engine/Scripting/ManagedCLR/MAssembly.cpp

@@ -352,6 +352,7 @@ bool MAssembly::LoadWithImage(const String& assemblyPath)
         }
     }
 
+    // TODO: load pdbs for custom third-party libs referenced by game assemblies for debugging
 #if 0
     // Hack to load debug information for Newtonsoft.Json (enable it to debug C# code of json lib)
     if (assemblyPath.EndsWith(TEXT("FlaxEngine.CSharp.dll")))

Source/Engine/Scripting/ManagedCLR/MCore.cpp

@@ -2,7 +2,6 @@
 
 #include "MCore.h"
 #include "MDomain.h"
-#include "MClass.h"
 #include "Engine/Core/Log.h"
 #include "Engine/Core/Types/String.h"
 #include "Engine/Core/Types/DateTime.h"
@@ -353,6 +352,9 @@ bool MCore::LoadEngine()
     PROFILE_CPU();
     ASSERT(Globals::MonoPath.IsANSI());
 
+    // Debugging Mono GC
+    //Platform::SetEnvironmentVariable(TEXT("MONO_GC_DEBUG"), TEXT("6:gc-log.txt,check-remset-consistency,nursery-canaries"));
+
 #if 0
     // Override memory allocation callback
     // TODO: use ENABLE_OVERRIDABLE_ALLOCATORS when building Mono to support memory callbacks or use counters for memory profiling

Source/Engine/Scripting/ManagedCLR/MUtils.cpp

@@ -114,7 +114,7 @@ MonoString* MUtils::ToString(const String& str)
 MonoString* MUtils::ToString(const String& str, MonoDomain* domain)
 {
     if (str.IsEmpty())
-        return mono_string_empty(mono_domain_get());
+        return mono_string_empty(domain);
     return mono_string_new_utf16(domain, (const mono_unichar2*)*str, str.Length());
 }
 

Source/Engine/Scripting/ManagedSerialization.cpp

@@ -10,7 +10,7 @@
 #include "ManagedCLR/MMethod.h"
 #include <ThirdParty/mono-2.0/mono/metadata/mono-debug.h>
 
-void ManagedSerialization::Serialize(ISerializable::SerializeStream& stream, MonoObject* object)
+void ManagedSerialization::Serialize(ISerializable::SerializeStream& stream, MObject* object)
 {
     if (!object)
     {
@@ -47,7 +47,7 @@ void ManagedSerialization::Serialize(ISerializable::SerializeStream& stream, Mon
     mono_free(invokeResultChars);
 }
 
-void ManagedSerialization::SerializeDiff(ISerializable::SerializeStream& stream, MonoObject* object, MonoObject* other)
+void ManagedSerialization::SerializeDiff(ISerializable::SerializeStream& stream, MObject* object, MObject* other)
 {
     if (!object || !other)
     {
@@ -85,7 +85,7 @@ void ManagedSerialization::SerializeDiff(ISerializable::SerializeStream& stream,
     mono_free(invokeResultChars);
 }
 
-void ManagedSerialization::Deserialize(ISerializable::DeserializeStream& stream, MonoObject* object)
+void ManagedSerialization::Deserialize(ISerializable::DeserializeStream& stream, MObject* object)
 {
     if (!object)
         return;
@@ -98,7 +98,7 @@ void ManagedSerialization::Deserialize(ISerializable::DeserializeStream& stream,
     Deserialize(StringAnsiView(buffer.GetString(), (int32)buffer.GetSize()), object);
 }
 
-void ManagedSerialization::Deserialize(const StringAnsiView& data, MonoObject* object)
+void ManagedSerialization::Deserialize(const StringAnsiView& data, MObject* object)
 {
     const char* str = data.Get();
     const int32 len = data.Length();

Source/Engine/Scripting/ManagedSerialization.h

@@ -18,7 +18,7 @@ public:
     /// </summary>
     /// <param name="stream">The output stream.</param>
     /// <param name="object">The object to serialize.</param>
-    static void Serialize(ISerializable::SerializeStream& stream, MonoObject* object);
+    static void Serialize(ISerializable::SerializeStream& stream, MObject* object);
 
     /// <summary>
     /// Serializes managed object difference to JSON.
@@ -26,20 +26,20 @@ public:
     /// <param name="stream">The output stream.</param>
     /// <param name="object">The object to serialize.</param>
     /// <param name="other">The reference object to serialize diff compared to it.</param>
-    static void SerializeDiff(ISerializable::SerializeStream& stream, MonoObject* object, MonoObject* other);
+    static void SerializeDiff(ISerializable::SerializeStream& stream, MObject* object, MObject* other);
 
     /// <summary>
     /// Deserializes managed object from the JSON.
     /// </summary>
     /// <param name="stream">The input stream.</param>
     /// <param name="object">The object to deserialize.</param>
-    static void Deserialize(ISerializable::DeserializeStream& stream, MonoObject* object);
+    static void Deserialize(ISerializable::DeserializeStream& stream, MObject* object);
 
     /// <summary>
     /// Deserializes managed object from the JSON.
     /// </summary>
     /// <param name="data">The input data.</param>
     /// <param name="object">The object to deserialize.</param>
-    static void Deserialize(const StringAnsiView& data, MonoObject* object);
+    static void Deserialize(const StringAnsiView& data, MObject* object);
 #endif
 };

Source/Tools/Flax.Build/Build/DotNet/Builder.DotNet.cs

@@ -160,7 +160,7 @@ namespace Flax.Build
 
                 // Prefer installed Roslyn C# compiler over Mono one
                 monoPath = null;
-                cscPath = Path.Combine(Path.GetDirectoryName(Deploy.VCEnvironment.MSBuildPath), "Roslyn", "csc.exe");
+                cscPath = Path.Combine(Path.GetDirectoryName(VCEnvironment.MSBuildPath), "Roslyn", "csc.exe");
 
                 if (!File.Exists(cscPath))
                 {

Source/Tools/Flax.Build/Utilities/Utilities.cs

@@ -244,6 +244,26 @@ namespace Flax.Build
             }
         }
 
+        /// <summary>
+        /// Deletes the directories inside a directory.
+        /// </summary>
+        /// <param name="directoryPath">The directory path.</param>
+        /// <param name="searchPattern">The custom filter for the directories to delete. Can be used to select files to delete. Null if unused.</param>
+        /// <param name="withSubdirs">if set to <c>true</c> with sub-directories (recursive delete operation).</param>
+        public static void DirectoriesDelete(string directoryPath, string searchPattern = null, bool withSubdirs = true)
+        {
+            if (!Directory.Exists(directoryPath))
+                return;
+            if (searchPattern == null)
+                searchPattern = "*";
+
+            var directories = Directory.GetDirectories(directoryPath, searchPattern, withSubdirs ? SearchOption.AllDirectories : SearchOption.TopDirectoryOnly);
+            for (int i = 0; i < directories.Length; i++)
+            {
+                DirectoryDelete(directories[i]);
+            }
+        }
+
         /// <summary>
         /// The process run options.
         /// </summary>