Use embeddable types

Ref: https://bugs.ruby-lang.org/issues/21853

Introduced in Ruby 3.3, will officially be public API in 4.1,
but can be used sooner by checking the existence of RUBY_TYPED_EMBEDDABLE

Author: byroot

ext/json/ext/generator/extconf.rb

@@ -5,6 +5,8 @@
   File.write('Makefile', dummy_makefile("").join)
 else
   append_cflags("-std=c99")
+  have_const("RUBY_TYPED_EMBEDDABLE", "ruby.h")  # RUBY_VERSION >= 3.3
+
   $defs << "-DJSON_GENERATOR"
   $defs << "-DJSON_DEBUG" if ENV.fetch("JSON_DEBUG", "0") != "0"
 

ext/json/ext/generator/generator.c

@@ -722,27 +722,20 @@ static void State_compact(void *ptr)
     state->as_json = rb_gc_location(state->as_json);
 }
 
-static void State_free(void *ptr)
-{
-    JSON_Generator_State *state = ptr;
-    ruby_xfree(state);
-}
-
 static size_t State_memsize(const void *ptr)
 {
     return sizeof(JSON_Generator_State);
 }
 
 static const rb_data_type_t JSON_Generator_State_type = {
-    "JSON/Generator/State",
-    {
+    .wrap_struct_name = "JSON/Generator/State",
+    .function = {
         .dmark = State_mark,
-        .dfree = State_free,
+        .dfree = RUBY_DEFAULT_FREE,
         .dsize = State_memsize,
         .dcompact = State_compact,
     },
-    0, 0,
-    RUBY_TYPED_WB_PROTECTED | RUBY_TYPED_FREE_IMMEDIATELY | RUBY_TYPED_FROZEN_SHAREABLE,
+    .flags = RUBY_TYPED_WB_PROTECTED | RUBY_TYPED_FREE_IMMEDIATELY | RUBY_TYPED_FROZEN_SHAREABLE | RUBY_TYPED_EMBEDDABLE,
 };
 
 static void state_init(JSON_Generator_State *state)

ext/json/ext/json.h

@@ -54,6 +54,10 @@ typedef unsigned char _Bool;
 #   define RUBY_TYPED_FROZEN_SHAREABLE 0
 #endif
 
+#ifndef HAVE_RUBY_TYPED_EMBEDDABLE
+# define RUBY_TYPED_EMBEDDABLE 0
+#endif
+
 #ifndef NORETURN
 #if defined(__has_attribute) && __has_attribute(noreturn)
 #define NORETURN(x) __attribute__((noreturn)) x
@@ -102,4 +106,6 @@ typedef unsigned char _Bool;
 #define JSON_CPU_LITTLE_ENDIAN_64BITS 0
 #endif
 
+
+
 #endif // _JSON_H_

ext/json/ext/parser/extconf.rb

@@ -6,6 +6,7 @@
 have_func("rb_str_to_interned_str", "ruby.h") # RUBY_VERSION >= 3.0
 have_func("rb_hash_new_capa", "ruby.h") # RUBY_VERSION >= 3.2
 have_func("rb_hash_bulk_insert", "ruby.h") # Missing on TruffleRuby
+have_const("RUBY_TYPED_EMBEDDABLE", "ruby.h")  # RUBY_VERSION >= 3.3
 
 append_cflags("-std=c99")
 

ext/json/ext/parser/parser.c

@@ -251,7 +251,9 @@ static void rvalue_stack_free(void *ptr)
     rvalue_stack *stack = (rvalue_stack *)ptr;
     if (stack) {
         ruby_xfree(stack->ptr);
+#ifndef HAVE_RUBY_TYPED_EMBEDDABLE
         ruby_xfree(stack);
+#endif
     }
 }
 
@@ -262,14 +264,13 @@ static size_t rvalue_stack_memsize(const void *ptr)
 }
 
 static const rb_data_type_t JSON_Parser_rvalue_stack_type = {
-    "JSON::Ext::Parser/rvalue_stack",
-    {
+    .wrap_struct_name = "JSON::Ext::Parser/rvalue_stack",
+    .function = {
         .dmark = rvalue_stack_mark,
         .dfree = rvalue_stack_free,
         .dsize = rvalue_stack_memsize,
     },
-    0, 0,
-    RUBY_TYPED_FREE_IMMEDIATELY,
+    .flags = RUBY_TYPED_FREE_IMMEDIATELY | RUBY_TYPED_EMBEDDABLE,
 };
 
 static rvalue_stack *rvalue_stack_spill(rvalue_stack *old_stack, VALUE *handle, rvalue_stack **stack_ref)
@@ -1608,7 +1609,9 @@ static void JSON_ParserConfig_mark(void *ptr)
 static void JSON_ParserConfig_free(void *ptr)
 {
     JSON_ParserConfig *config = ptr;
+#ifndef HAVE_RUBY_TYPED_EMBEDDABLE
     ruby_xfree(config);
+#endif
 }
 
 static size_t JSON_ParserConfig_memsize(const void *ptr)
@@ -1617,14 +1620,13 @@ static size_t JSON_ParserConfig_memsize(const void *ptr)
 }
 
 static const rb_data_type_t JSON_ParserConfig_type = {
-    "JSON::Ext::Parser/ParserConfig",
-    {
+    .wrap_struct_name = "JSON::Ext::Parser/ParserConfig",
+    .function = {
         JSON_ParserConfig_mark,
         JSON_ParserConfig_free,
         JSON_ParserConfig_memsize,
     },
-    0, 0,
-    RUBY_TYPED_FREE_IMMEDIATELY | RUBY_TYPED_WB_PROTECTED | RUBY_TYPED_FROZEN_SHAREABLE,
+    .flags = RUBY_TYPED_FREE_IMMEDIATELY | RUBY_TYPED_WB_PROTECTED | RUBY_TYPED_FROZEN_SHAREABLE | RUBY_TYPED_EMBEDDABLE,
 };
 
 static VALUE cJSON_parser_s_allocate(VALUE klass)