From 2176954aeef668068df51ac8850c0425c8d1d44c Mon Sep 17 00:00:00 2001
From: arch1t3cht <arch1t3cht@gmail.com>
Date: Tue, 26 Jul 2022 21:26:25 +0200
Subject: [PATCH] Folding: Pass fold data through Lua

This way, automation scripts won't nuke the fold data on any lines they
modify.
This is done as userdata for now, so scripts that don't know what
they're doing don't break the folds even further. If scripts get more
access to folds, it should be with a safer and simpler API.
---
 src/auto4_lua_assfile.cpp | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/src/auto4_lua_assfile.cpp b/src/auto4_lua_assfile.cpp
index 3aef3b769..f98e0a35d 100644
--- a/src/auto4_lua_assfile.cpp
+++ b/src/auto4_lua_assfile.cpp
@@ -40,6 +40,7 @@
 #include "ass_karaoke.h"
 #include "ass_style.h"
 #include "compat.h"
+#include "fold_controller.h"
 
 #include <libaegisub/exception.h>
 #include <libaegisub/log.h>
@@ -100,6 +101,16 @@ namespace {
 		return ret;
 	}
 
+	template<typename T>
+	void get_userdata_field(lua_State *L, const char *name, const char *line_class, T *target)
+	{
+		lua_getfield(L, -1, name);
+		if (!lua_isuserdata(L, -1))
+			throw bad_field("userdata", name, line_class);
+		*target = *static_cast<T *>(lua_touserdata(L, -1));
+		lua_pop(L, 1);
+	}
+
 	using namespace Automation4;
 	template<int (LuaAssFile::*closure)(lua_State *)>
 	int closure_wrapper(lua_State *L)
@@ -181,6 +192,10 @@ namespace Automation4 {
 
 			set_field(L, "text", dia->Text);
 
+			// preserve the folds
+			*static_cast<FoldInfo*>(lua_newuserdata(L, sizeof(FoldInfo))) = dia->Fold;
+			lua_setfield(L, -2, "_foldinfo");
+
 			// create extradata table
 			lua_newtable(L);
 			for (auto const& ed : ass->GetExtradata(dia->ExtradataIds)) {
@@ -301,6 +316,7 @@ namespace Automation4 {
 			dia->Margin[2] = get_int_field(L, "margin_t", "dialogue");
 			dia->Effect = get_string_field(L, "effect", "dialogue");
 			dia->Text = get_string_field(L, "text", "dialogue");
+			get_userdata_field(L, "_foldinfo", "dialogue", &dia->Fold);
 
 			std::vector<uint32_t> new_ids;