C#: Add source generator for properties and exports default values

The editor no longer needs to create temporary instances to get the
default values. The initializer values of the exported properties are
still evaluated at runtime. For example, in the following example,
`GetInitialValue()` will be called when first looks for default values:

```
[Export] int MyValue = GetInitialValue();
```

Exporting fields with a non-supported type now results in a compiler
error rather than a runtime error when the script is used.

1 files changed, 25 insertions, 3 deletions

diff --git a/modules/mono/mono_gd/gd_mono_cache.h b/modules/mono/mono_gd/gd_mono_cache.h
index b993facff9..7a75532fb7 100644
--- a/modules/mono/mono_gd/gd_mono_cache.h
+++ b/modules/mono/mono_gd/gd_mono_cache.h
@@ -34,6 +34,7 @@
 #include <stdint.h>
 
 #include "../csharp_script.h"
+#include "../interop_types.h"
 #include "../mono_gc_handle.h"
 #include "core/object/object.h"
 #include "core/string/string_name.h"
@@ -52,16 +53,33 @@ namespace GDMonoCache {
 #define GD_CLR_STDCALL
 #endif
 
+struct godotsharp_property_info {
+	godot_string_name name; // Not owned
+	godot_string hint_string;
+	Variant::Type type;
+	PropertyHint hint;
+	PropertyUsageFlags usage;
+	bool exported;
+};
+
+struct godotsharp_property_def_val_pair {
+	godot_string_name name; // Not owned
+	godot_variant value;
+};
+
 struct ManagedCallbacks {
+	using Callback_ScriptManagerBridge_GetPropertyInfoList_Add = void(GD_CLR_STDCALL *)(CSharpScript *p_script, const String *, godotsharp_property_info *p_props, int32_t p_count);
+	using Callback_ScriptManagerBridge_GetPropertyDefaultValues_Add = void(GD_CLR_STDCALL *)(CSharpScript *p_script, godotsharp_property_def_val_pair *p_def_vals, int32_t p_count);
+
 	using FuncSignalAwaiter_SignalCallback = void(GD_CLR_STDCALL *)(GCHandleIntPtr, const Variant **, int32_t, bool *);
 	using FuncDelegateUtils_InvokeWithVariantArgs = void(GD_CLR_STDCALL *)(GCHandleIntPtr, const Variant **, uint32_t, const Variant *);
 	using FuncDelegateUtils_DelegateEquals = bool(GD_CLR_STDCALL *)(GCHandleIntPtr, GCHandleIntPtr);
 	using FuncScriptManagerBridge_FrameCallback = void(GD_CLR_STDCALL *)();
 	using FuncScriptManagerBridge_CreateManagedForGodotObjectBinding = GCHandleIntPtr(GD_CLR_STDCALL *)(const StringName *, Object *);
-	using FuncScriptManagerBridge_CreateManagedForGodotObjectScriptInstance = bool(GD_CLR_STDCALL *)(const CSharpScript *, Object *, const Variant **, int);
+	using FuncScriptManagerBridge_CreateManagedForGodotObjectScriptInstance = bool(GD_CLR_STDCALL *)(const CSharpScript *, Object *, const Variant **, int32_t);
 	using FuncScriptManagerBridge_GetScriptNativeName = void(GD_CLR_STDCALL *)(const CSharpScript *, StringName *);
 	using FuncScriptManagerBridge_SetGodotObjectPtr = void(GD_CLR_STDCALL *)(GCHandleIntPtr, Object *);
-	using FuncScriptManagerBridge_RaiseEventSignal = void(GD_CLR_STDCALL *)(GCHandleIntPtr, const StringName *, const Variant **, int, bool *);
+	using FuncScriptManagerBridge_RaiseEventSignal = void(GD_CLR_STDCALL *)(GCHandleIntPtr, const StringName *, const Variant **, int32_t, bool *);
 	using FuncScriptManagerBridge_GetScriptSignalList = void(GD_CLR_STDCALL *)(const CSharpScript *, Dictionary *);
 	using FuncScriptManagerBridge_HasScriptSignal = bool(GD_CLR_STDCALL *)(const CSharpScript *, const String *);
 	using FuncScriptManagerBridge_ScriptIsOrInherits = bool(GD_CLR_STDCALL *)(const CSharpScript *, const CSharpScript *);
@@ -69,7 +87,9 @@ struct ManagedCallbacks {
 	using FuncScriptManagerBridge_RemoveScriptBridge = void(GD_CLR_STDCALL *)(const CSharpScript *);
 	using FuncScriptManagerBridge_UpdateScriptClassInfo = void(GD_CLR_STDCALL *)(const CSharpScript *, bool *, Dictionary *);
 	using FuncScriptManagerBridge_SwapGCHandleForType = bool(GD_CLR_STDCALL *)(GCHandleIntPtr, GCHandleIntPtr *, bool);
-	using FuncCSharpInstanceBridge_Call = bool(GD_CLR_STDCALL *)(GCHandleIntPtr, const StringName *, const Variant **, int, Callable::CallError *, Variant *);
+	using FuncScriptManagerBridge_GetPropertyInfoList = void(GD_CLR_STDCALL *)(CSharpScript *, Callback_ScriptManagerBridge_GetPropertyInfoList_Add);
+	using FuncScriptManagerBridge_GetPropertyDefaultValues = void(GD_CLR_STDCALL *)(CSharpScript *, Callback_ScriptManagerBridge_GetPropertyDefaultValues_Add);
+	using FuncCSharpInstanceBridge_Call = bool(GD_CLR_STDCALL *)(GCHandleIntPtr, const StringName *, const Variant **, int32_t, Callable::CallError *, Variant *);
 	using FuncCSharpInstanceBridge_Set = bool(GD_CLR_STDCALL *)(GCHandleIntPtr, const StringName *, const Variant *);
 	using FuncCSharpInstanceBridge_Get = bool(GD_CLR_STDCALL *)(GCHandleIntPtr, const StringName *, Variant *);
 	using FuncCSharpInstanceBridge_CallDispose = void(GD_CLR_STDCALL *)(GCHandleIntPtr, bool);
@@ -96,6 +116,8 @@ struct ManagedCallbacks {
 	FuncScriptManagerBridge_RemoveScriptBridge ScriptManagerBridge_RemoveScriptBridge;
 	FuncScriptManagerBridge_UpdateScriptClassInfo ScriptManagerBridge_UpdateScriptClassInfo;
 	FuncScriptManagerBridge_SwapGCHandleForType ScriptManagerBridge_SwapGCHandleForType;
+	FuncScriptManagerBridge_GetPropertyInfoList ScriptManagerBridge_GetPropertyInfoList;
+	FuncScriptManagerBridge_GetPropertyDefaultValues ScriptManagerBridge_GetPropertyDefaultValues;
 	FuncCSharpInstanceBridge_Call CSharpInstanceBridge_Call;
 	FuncCSharpInstanceBridge_Set CSharpInstanceBridge_Set;
 	FuncCSharpInstanceBridge_Get CSharpInstanceBridge_Get;