Refactor EditorPlugins to properly initialize and deinitialize

Source/Editor/Editor.cs

@@ -571,7 +571,13 @@ namespace FlaxEditor
 
             // Deinitialize Editor Plugins
             foreach (var plugin in PluginManager.EditorPlugins)
-                ((EditorPlugin)plugin).DeinitializeEditor();
+            {
+                if (plugin is EditorPlugin editorPlugin && editorPlugin._isEditorInitialized)
+                {
+                    editorPlugin._isEditorInitialized = false;
+                    editorPlugin.DeinitializeEditor();
+                }
+            }
 
             // Start exit
             StateMachine.GoToState<ClosingState>();

Source/Editor/Plugins/EditorPlugin.cs

@@ -5,15 +5,10 @@ using FlaxEngine;
 
 namespace FlaxEditor
 {
-    /// <summary>
-    /// Base class for all plugins used in Editor.
-    /// </summary>
-    /// <remarks>
-    /// Plugins should have a public and parameter-less constructor.
-    /// </remarks>
-    /// <seealso cref="FlaxEngine.Plugin" />
-    public abstract class EditorPlugin : Plugin
+    partial class EditorPlugin
     {
+        internal bool _isEditorInitialized;
+
         /// <summary>
         /// Gets the type of the <see cref="GamePlugin"/> that is related to this plugin. Some plugins may be used only in editor while others want to gave a runtime representation. Use this property to link the related game plugin.
         /// </summary>
@@ -24,14 +19,12 @@ namespace FlaxEditor
         /// </summary>
         public Editor Editor { get; private set; }
 
-        /// <inheritdoc />
-        public override void Initialize()
+        internal void Initialize_Internal()
         {
-            base.Initialize();
-
             Editor = Editor.Instance;
             if (Editor.IsInitialized)
             {
+                _isEditorInitialized = true;
                 InitializeEditor();
             }
             else
@@ -40,9 +33,21 @@ namespace FlaxEditor
             }
         }
 
+        internal void Deinitialize_Internal()
+        {
+            if (_isEditorInitialized)
+            {
+                _isEditorInitialized = false;
+                DeinitializeEditor();
+            }
+        }
+
         private void OnEditorInitializationEnd()
         {
             Editor.InitializationEnd -= OnEditorInitializationEnd;
+            if (_isEditorInitialized)
+                return;
+            _isEditorInitialized = true;
             InitializeEditor();
         }
 

Source/Engine/Scripting/Plugins/EditorPlugin.h

@@ -0,0 +1,24 @@
+// Copyright (c) 2012-2022 Wojciech Figat. All rights reserved.
+
+#pragma once
+
+#include "Plugin.h"
+
+#if USE_EDITOR
+
+/// <summary>
+/// Base class for all plugins used in Editor.
+/// </summary>
+/// <remarks>
+/// Plugins should have a public and parameter-less constructor.
+/// </remarks>
+/// <seealso cref="FlaxEngine.Plugin" />
+API_CLASS(Abstract, Namespace="FlaxEditor") class FLAXENGINE_API EditorPlugin : public Plugin
+{
+    DECLARE_SCRIPTING_TYPE(EditorPlugin);
+public:
+    void Initialize() override;
+    void Deinitialize() override;
+};
+
+#endif

Source/Engine/Scripting/Plugins/PluginManager.cpp

@@ -27,6 +27,45 @@ GamePlugin::GamePlugin(const SpawnParams& params)
 {
 }
 
+#if USE_EDITOR
+
+#include "EditorPlugin.h"
+#include "Engine/Scripting/MException.h"
+#include "Engine/Scripting/ManagedCLR/MMethod.h"
+
+EditorPlugin::EditorPlugin(const SpawnParams& params)
+    : Plugin(params)
+{
+}
+
+void EditorPlugin::Initialize()
+{
+    Plugin::Initialize();
+
+    MObject* exception = nullptr;
+    TypeInitializer.GetType().ManagedClass->GetMethod("Initialize_Internal")->Invoke(GetOrCreateManagedInstance(), nullptr, &exception);
+    if (exception)
+    {
+        MException ex(exception);
+        ex.Log(LogType::Error,TEXT("EditorPlugin"));
+    }
+}
+
+void EditorPlugin::Deinitialize()
+{
+    MObject* exception = nullptr;
+    TypeInitializer.GetType().ManagedClass->GetMethod("Deinitialize_Internal")->Invoke(GetOrCreateManagedInstance(), nullptr, &exception);
+    if (exception)
+    {
+        MException ex(exception);
+        ex.Log(LogType::Error,TEXT("EditorPlugin"));
+    }
+
+    Plugin::Deinitialize();
+}
+
+#endif
+
 Delegate<Plugin*> PluginManager::PluginLoading;
 Delegate<Plugin*> PluginManager::PluginLoaded;
 Delegate<Plugin*> PluginManager::PluginUnloading;
@@ -42,6 +81,7 @@ namespace PluginManagerImpl
     void OnAssemblyLoaded(MAssembly* assembly);
     void OnAssemblyUnloading(MAssembly* assembly);
     void OnBinaryModuleLoaded(BinaryModule* module);
+    void OnScriptsReloading();
 }
 
 using namespace PluginManagerImpl;
@@ -211,6 +251,32 @@ void PluginManagerImpl::OnBinaryModuleLoaded(BinaryModule* module)
     managedModule->Assembly->Unloading.Bind(OnAssemblyUnloading);
 }
 
+void PluginManagerImpl::OnScriptsReloading()
+{
+    // When scripting is reloading (eg. for hot-reload in Editor) we have to deinitialize plugins (Scripting service destroys C# objects later on)
+    bool changed = false;
+    for (int32 i = EditorPlugins.Count() - 1; i >= 0 && EditorPlugins.Count() > 0; i--)
+    {
+        auto plugin = EditorPlugins[i];
+        {
+            PluginManagerService::InvokeDeinitialize(plugin);
+            EditorPlugins.RemoveAtKeepOrder(i);
+            changed = true;
+        }
+    }
+    for (int32 i = GamePlugins.Count() - 1; i >= 0 && GamePlugins.Count() > 0; i--)
+    {
+        auto plugin = GamePlugins[i];
+        {
+            PluginManagerService::InvokeDeinitialize(plugin);
+            GamePlugins.RemoveAtKeepOrder(i);
+            changed = true;
+        }
+    }
+    if (changed)
+        PluginManager::PluginsChanged();
+}
+
 bool PluginManagerService::Init()
 {
     // Process already loaded modules
@@ -221,6 +287,7 @@ bool PluginManagerService::Init()
 
     // Register for new binary modules load actions
     Scripting::BinaryModuleLoaded.Bind(&OnBinaryModuleLoaded);
+    Scripting::ScriptsReloading.Bind(&OnScriptsReloading);
 
     return false;
 }
@@ -228,6 +295,7 @@ bool PluginManagerService::Init()
 void PluginManagerService::Dispose()
 {
     Scripting::BinaryModuleLoaded.Unbind(&OnBinaryModuleLoaded);
+    Scripting::ScriptsReloading.Unbind(&OnScriptsReloading);
 
     // Cleanup all plugins
     PROFILE_CPU_NAMED("Dispose Plugins");