Make mruby raii cleanup, and fix cleanup bug.

- Functions were cleaned up after mruby, which was wrong.
- Becuase functions could have stored a reference to a Block which refers to mruby.
- And so it would crash on release builds at exit if custom functions were used.

include/bed.h

@@ -14,6 +14,7 @@
 
 namespace bed {
 struct BEd {
+  internal::scripting::RubyState mrb;
   internal::trie::Trie<internal::functions::Function> functions;
   internal::functions::Function no_op;
   internal::functions::Function eof_op;
@@ -24,9 +25,6 @@ struct BEd {
   internal::vase::AppendStorage append{"/tmp"};
   std::unordered_map<std::string, internal::buffer::Buffer *> buffers;
 
-  mrb_state *mrb = nullptr;
-  int arena;
-
   bool help_mode = false;
   bool prompt_mode = true;
   std::function<std::string(BEd &)> prompt = nullptr;

include/internal/scripting/ruby.h

@@ -4,6 +4,30 @@
 #include "pch.h"
 
 namespace bed::internal::scripting {
+struct RubyState {
+  mrb_state *state = nullptr;
+  int arena = 0;
+
+  explicit RubyState(BEd *ctx) : state(mrb_open()) {
+    if (!state)
+      throw fatal_error("Failed to initialize mruby.", 1);
+    state->ud = ctx;
+    arena = mrb_gc_arena_save(state);
+  }
+
+  ~RubyState() {
+    state->ud = nullptr;
+    if (state) {
+      mrb_gc_arena_restore(state, arena);
+      mrb_full_gc(state);
+      mrb_close(state);
+    }
+  }
+
+  RubyState(const RubyState &) = delete;
+  RubyState &operator=(const RubyState &) = delete;
+};
+
 struct Block {
   mrb_state *mrb = nullptr;
   mrb_value proc = mrb_nil_value();

src/bed/bed.cc

@@ -2,7 +2,7 @@
 
 namespace bed {
 BEd::BEd(std::vector<std::string> args)
-    : theme(internal::theme::Theme::default_theme()), io(*this) {
+    : mrb(this), theme(internal::theme::Theme::default_theme()), io(*this) {
   std::string prompt_ = "";
   std::string file = "";
   bool suppress = false;
@@ -42,11 +42,6 @@ BEd::BEd(std::vector<std::string> args)
       && strcmp(colorterm, "24bit") != 0)
     color = false;
   color_mode = color;
-  mrb = mrb_open();
-  if (!mrb)
-    throw fatal_error("Failed to initialize mruby.", 1);
-  mrb->ud = this;
-  arena = mrb_gc_arena_save(mrb);
   internal::functions::Function::register_posix(*this);
   internal::functions::Function::register_extented(*this);
   internal::functions::Suffix::register_suffixes(*this);
@@ -70,12 +65,6 @@ BEd::~BEd() {
     delete buffer;
   for (auto &[_, lang] : languages)
     delete lang;
-  mrb->ud = nullptr;
-  if (mrb) {
-    mrb_gc_arena_restore(mrb, arena);
-    mrb_full_gc(mrb);
-    mrb_close(mrb);
-  }
 }
 
 void BEd::print_help() {

src/internal/scripting/ruby.cc

@@ -105,17 +105,18 @@ static mrb_value mrb_bed_unregister(mrb_state *mrb, mrb_value) {
 }
 
 void register_basic(BEd &ctx) {
+  auto mrb = ctx.mrb.state;
   auto *bed_error =
-    mrb_define_class(ctx.mrb, "EdError", mrb_exc_get_id(ctx.mrb, MRB_ERROR_SYM(RuntimeError)));
-  mrb_define_class(ctx.mrb, "FatalError", bed_error);
-  mrb_define_method(ctx.mrb, ctx.mrb->kernel_module, "exit", mrb_bed_exit, MRB_ARGS_NONE());
-  mrb_define_method(ctx.mrb, ctx.mrb->kernel_module, "handle", mrb_bed_handle, MRB_ARGS_REQ(1));
-  mrb_define_method(ctx.mrb, ctx.mrb->kernel_module, "register", mrb_bed_register, MRB_ARGS_REQ(1) | MRB_ARGS_OPT(1) | MRB_ARGS_BLOCK());
-  mrb_define_method(ctx.mrb, ctx.mrb->kernel_module, "unregister", mrb_bed_unregister, MRB_ARGS_REQ(1));
+    mrb_define_class(mrb, "EdError", mrb_exc_get_id(mrb, MRB_ERROR_SYM(RuntimeError)));
+  mrb_define_class(mrb, "FatalError", bed_error);
+  mrb_define_method(mrb, mrb->kernel_module, "exit", mrb_bed_exit, MRB_ARGS_NONE());
+  mrb_define_method(mrb, mrb->kernel_module, "handle", mrb_bed_handle, MRB_ARGS_REQ(1));
+  mrb_define_method(mrb, mrb->kernel_module, "register", mrb_bed_register, MRB_ARGS_REQ(1) | MRB_ARGS_OPT(1) | MRB_ARGS_BLOCK());
+  mrb_define_method(mrb, mrb->kernel_module, "unregister", mrb_bed_unregister, MRB_ARGS_REQ(1));
 }
 
 void run(BEd &ctx, const std::string &str) {
-  mrb_state *mrb = ctx.mrb;
+  mrb_state *mrb = ctx.mrb.state;
   mrb_load_nstring(mrb, str.data(), str.size());
   if (!mrb->exc)
     return;