From 532df66e0734a205d1e65b149bde7e1111c4000b Mon Sep 17 00:00:00 2001
From: Andy Wingo <wingo@pobox.com>
Date: Fri, 2 May 2025 16:16:57 +0200
Subject: [PATCH] Refactor to how struct and smob finalization works

* libguile/finalizers.h:
* libguile/finalizers.c (scm_i_add_struct_finalizer):
(scm_i_add_smob_finalizer): New internal API.
* libguile/smob.c (scm_i_new_smob):
(scm_i_new_double_smob):
* libguile/struct.c (scm_i_alloc_struct): Use it.
---
 libguile/finalizers.c | 34 ++++++++++++++++++++++++++++++++++
 libguile/finalizers.h |  5 +++++
 libguile/smob.c       | 10 ++--------
 libguile/struct.c     |  8 +-------
 4 files changed, 42 insertions(+), 15 deletions(-)

diff --git a/libguile/finalizers.c b/libguile/finalizers.c
index 816e87351..0f3f7a5cc 100644
--- a/libguile/finalizers.c
+++ b/libguile/finalizers.c
@@ -40,6 +40,8 @@
 #include "gsubr.h"
 #include "init.h"
 #include "numbers.h"
+#include "struct.h"
+#include "smob.h"
 #include "threads.h"
 #include "version.h"
 
@@ -150,6 +152,38 @@ scm_i_add_finalizer (void *obj, scm_t_finalizer_proc proc, void *data)
   shuffle_resuscitators_to_front (chained_data);
 }
 
+static void
+struct_finalizer_trampoline (void *ptr, void *data)
+{
+  scm_i_finalize_struct (SCM_I_CURRENT_THREAD, PTR2SCM (ptr));
+}
+
+static void
+smob_finalizer_trampoline (void *ptr, void *data)
+{
+  scm_i_finalize_smob (SCM_I_CURRENT_THREAD, PTR2SCM (ptr));
+}
+
+SCM
+scm_i_add_struct_finalizer (struct scm_thread *thread, SCM obj)
+{
+  if (!SCM_STRUCTP (obj))
+    abort ();
+
+  scm_i_set_finalizer (SCM2PTR (obj), struct_finalizer_trampoline, NULL);
+  return SCM_UNSPECIFIED;
+}
+
+SCM
+scm_i_add_smob_finalizer (struct scm_thread *thread, SCM obj)
+{
+  if (!SCM_HAS_TYP7 (obj, scm_tc7_smob))
+    abort ();
+
+  scm_i_set_finalizer (SCM2PTR (obj), smob_finalizer_trampoline, NULL);
+  return SCM_UNSPECIFIED;
+}
+
 static void
 invoke_finalizer (void *obj, void *data)
 {
diff --git a/libguile/finalizers.h b/libguile/finalizers.h
index 3b4ec8af5..941849f6e 100644
--- a/libguile/finalizers.h
+++ b/libguile/finalizers.h
@@ -35,6 +35,11 @@ SCM_INTERNAL void scm_i_add_finalizer (void *obj, scm_t_finalizer_proc,
 SCM_INTERNAL void scm_i_add_resuscitator (void *obj, scm_t_finalizer_proc,
                                           void *data);
 
+SCM_INTERNAL SCM scm_i_add_struct_finalizer (struct scm_thread *thread,
+                                             SCM obj);
+SCM_INTERNAL SCM scm_i_add_smob_finalizer (struct scm_thread *thread,
+                                           SCM obj);
+
 SCM_INTERNAL void scm_i_finalizer_pre_fork (void);
 
 /* Return true if THREAD is the finalizer thread.  */
diff --git a/libguile/smob.c b/libguile/smob.c
index 4fba079d9..917cf1cb5 100644
--- a/libguile/smob.c
+++ b/libguile/smob.c
@@ -403,12 +403,6 @@ scm_i_finalize_smob (struct scm_thread *thread, SCM smob)
     free_smob (smob);
 }
 
-static void
-finalize_smob (void *ptr, void *data)
-{
-  return scm_i_finalize_smob (SCM_I_CURRENT_THREAD, PTR2SCM (ptr));
-}
-
 /* Return a SMOB with typecode TC.  The SMOB type corresponding to TC may
    provide a custom mark procedure and it will be honored.  */
 SCM
@@ -430,7 +424,7 @@ scm_i_new_smob (scm_t_bits tc, scm_t_bits data)
   SCM_SET_CELL_WORD_0 (ret, tc);
 
   if (scm_smobs[smobnum].free)
-    scm_i_set_finalizer (SCM2PTR (ret), finalize_smob, NULL);
+    scm_i_add_smob_finalizer (SCM_I_CURRENT_THREAD, ret);
 
   return ret;
 }
@@ -457,7 +451,7 @@ scm_i_new_double_smob (scm_t_bits tc, scm_t_bits data1,
   SCM_SET_CELL_WORD_0 (ret, tc);
 
   if (scm_smobs[smobnum].free)
-    scm_i_set_finalizer (SCM2PTR (ret), finalize_smob, NULL);
+    scm_i_add_smob_finalizer (SCM_I_CURRENT_THREAD, ret);
 
   return ret;
 }
diff --git a/libguile/struct.c b/libguile/struct.c
index 671f7e14b..f41859cda 100644
--- a/libguile/struct.c
+++ b/libguile/struct.c
@@ -319,12 +319,6 @@ scm_i_finalize_struct (struct scm_thread *thread, SCM obj)
     finalize (obj);
 }
 
-static void
-struct_finalizer_trampoline (void *ptr, void *data)
-{
-  scm_i_finalize_struct (SCM_I_CURRENT_THREAD, PTR2SCM (ptr));
-}
-
 /* A struct is a sequence of words preceded by a pointer to the struct's
    vtable.  The vtable reference is tagged with the struct tc3.  */
 static SCM
@@ -337,7 +331,7 @@ scm_i_alloc_struct (scm_t_bits vtable_bits, int n_words)
   /* vtable_bits can be 0 when making a vtable vtable */
   if (vtable_bits && SCM_VTABLE_INSTANCE_FINALIZER (SCM_PACK (vtable_bits)))
     /* Register a finalizer for the newly created instance.  */
-    scm_i_set_finalizer (SCM2PTR (ret), struct_finalizer_trampoline, NULL);
+    scm_i_add_struct_finalizer (SCM_I_CURRENT_THREAD, ret);
 
   return ret;
 }