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 +54,17 @@ typedef unsigned char _Bool;
 #   define RUBY_TYPED_FROZEN_SHAREABLE 0
 #endif
 
+#ifdef RUBY_TYPED_EMBEDDABLE
+#  define HAVE_RUBY_TYPED_EMBEDDABLE 1
+#else
+# ifdef HAVE_CONST_RUBY_TYPED_EMBEDDABLE
+#  define RUBY_TYPED_EMBEDDABLE RUBY_TYPED_EMBEDDABLE
+#  define HAVE_RUBY_TYPED_EMBEDDABLE 1
+# else
+#  define RUBY_TYPED_EMBEDDABLE 0
+# endif
+#endif
+
 #ifndef NORETURN
 #if defined(__has_attribute) && __has_attribute(noreturn)
 #define NORETURN(x) __attribute__((noreturn)) x

ext/json/ext/parser/extconf.rb

@@ -7,6 +7,10 @@
 have_func("rb_hash_new_capa", "ruby.h") # RUBY_VERSION >= 3.2
 have_func("rb_hash_bulk_insert", "ruby.h") # Missing on TruffleRuby
 
+if RUBY_ENGINE == "ruby"
+  have_const("RUBY_TYPED_EMBEDDABLE", "ruby.h") # RUBY_VERSION >= 3.3
+end
+
 append_cflags("-std=c99")
 
 if enable_config('parser-use-simd', default=!ENV["JSON_DISABLE_SIMD"])

ext/json/ext/parser/parser.c

@@ -246,12 +246,20 @@ static void rvalue_stack_mark(void *ptr)
     }
 }
 
+static void rvalue_stack_free_buffer(rvalue_stack *stack)
+{
+    ruby_xfree(stack->ptr);
+    stack->ptr = NULL;
+}
+
 static void rvalue_stack_free(void *ptr)
 {
     rvalue_stack *stack = (rvalue_stack *)ptr;
     if (stack) {
-        ruby_xfree(stack->ptr);
+        rvalue_stack_free_buffer(stack);
+#ifndef HAVE_RUBY_TYPED_EMBEDDABLE
         ruby_xfree(stack);
+#endif
     }
 }
 
@@ -262,14 +270,13 @@ 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)
@@ -291,8 +298,12 @@ static void rvalue_stack_eagerly_release(VALUE handle)
     if (handle) {
         rvalue_stack *stack;
         TypedData_Get_Struct(handle, rvalue_stack, &JSON_Parser_rvalue_stack_type, stack);
-        RTYPEDDATA_DATA(handle) = NULL;
+#ifdef HAVE_RUBY_TYPED_EMBEDDABLE
+        rvalue_stack_free_buffer(stack);
+#else
         rvalue_stack_free(stack);
+        RTYPEDDATA_DATA(handle) = NULL;
+#endif
     }
 }
 
@@ -343,7 +354,7 @@ typedef struct JSON_ParserStruct {
 } JSON_ParserConfig;
 
 typedef struct JSON_ParserStateStruct {
-    VALUE stack_handle;
+    VALUE *stack_handle;
     const char *start;
     const char *cursor;
     const char *end;
@@ -944,7 +955,7 @@ static inline VALUE json_push_value(JSON_ParserState *state, JSON_ParserConfig *
     if (RB_UNLIKELY(config->on_load_proc)) {
         value = rb_proc_call_with_block(config->on_load_proc, 1, &value, Qnil);
     }
-    rvalue_stack_push(state->stack, value, &state->stack_handle, &state->stack);
+    rvalue_stack_push(state->stack, value, state->stack_handle, &state->stack);
     return value;
 }
 
@@ -1554,20 +1565,22 @@ static VALUE cParser_parse(JSON_ParserConfig *config, VALUE Vsource)
     const char *start;
     RSTRING_GETMEM(Vsource, start, len);
 
+    VALUE stack_handle = 0;
     JSON_ParserState _state = {
         .start = start,
         .cursor = start,
         .end = start + len,
         .stack = &stack,
+        .stack_handle = &stack_handle,
     };
     JSON_ParserState *state = &_state;
 
     VALUE result = json_parse_any(state, config);
 
     // This may be skipped in case of exception, but
     // it won't cause a leak.
-    rvalue_stack_eagerly_release(state->stack_handle);
-
+    rvalue_stack_eagerly_release(stack_handle);
+    RB_GC_GUARD(stack_handle);
     json_ensure_eof(state);
 
     return result;
@@ -1605,26 +1618,19 @@ static void JSON_ParserConfig_mark(void *ptr)
     rb_gc_mark(config->decimal_class);
 }
 
-static void JSON_ParserConfig_free(void *ptr)
-{
-    JSON_ParserConfig *config = ptr;
-    ruby_xfree(config);
-}
-
 static size_t JSON_ParserConfig_memsize(const void *ptr)
 {
     return sizeof(JSON_ParserConfig);
 }
 
 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,
+        RUBY_DEFAULT_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)