add scm_i_set_finalizer, scm_i_add_finalizer, scm_i_add_resuscitator

* libguile/finalizers.h:
* libguile/finalizers.c: New files.

* libguile.h:
* libguile/Makefile.am: Add to build.

libguile.h

@@ -1,7 +1,7 @@
 #ifndef SCM_LIBGUILE_H
 #define SCM_LIBGUILE_H
 
-/* Copyright (C) 1995,1996,1997,1998,2000,2001, 2002, 2003, 2004, 2006, 2008, 2009, 2010, 2011 Free Software Foundation, Inc.
+/* Copyright (C) 1995,1996,1997,1998,2000,2001, 2002, 2003, 2004, 2006, 2008, 2009, 2010, 2011, 2012 Free Software Foundation, Inc.
  * 
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public License
@@ -49,6 +49,7 @@ extern "C" {
 #include "libguile/extensions.h"
 #include "libguile/feature.h"
 #include "libguile/filesys.h"
+#include "libguile/finalizers.h"
 #include "libguile/fluids.h"
 #include "libguile/foreign.h"
 #include "libguile/fports.h"

libguile/Makefile.am

@@ -1,6 +1,6 @@
 ## Process this file with Automake to create Makefile.in
 ##
-##  	Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2006, 2007, 2008, 2009, 2010, 2011 Free Software Foundation, Inc.
+##  	Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2006, 2007, 2008, 2009, 2010, 2011, 2012 Free Software Foundation, Inc.
 ##
 ##   This file is part of GUILE.
 ##
@@ -142,6 +142,7 @@ libguile_@GUILE_EFFECTIVE_VERSION@_la_SOURCES =				\
 	extensions.c				\
 	feature.c				\
 	filesys.c				\
+	finalizers.c				\
 	fluids.c				\
 	foreign.c				\
 	fports.c				\
@@ -530,6 +531,7 @@ modinclude_HEADERS =				\
 	expand.h				\
 	extensions.h				\
 	feature.h				\
+	finalizers.h				\
 	filesys.h				\
 	fluids.h				\
 	foreign.h				\

libguile/finalizers.c

@@ -0,0 +1,126 @@
+/* Copyright (C) 2012 Free Software Foundation, Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public License
+ * as published by the Free Software Foundation; either version 3 of
+ * the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301 USA
+ */
+
+
+
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+#include "libguile/bdw-gc.h"
+#include "libguile/_scm.h"
+#include "libguile/finalizers.h"
+#include "libguile/gc.h"
+#include "libguile/threads.h"
+
+
+
+void
+scm_i_set_finalizer (void *obj, scm_t_finalizer_proc proc, void *data)
+{
+  GC_finalization_proc prev;
+  GC_PTR prev_data;
+  GC_REGISTER_FINALIZER_NO_ORDER (obj, proc, data, &prev, &prev_data);
+}
+
+struct scm_t_chained_finalizer
+{
+  int resuscitating_p;
+  scm_t_finalizer_proc proc;
+  void *data;
+  scm_t_finalizer_proc prev;
+  void *prev_data;
+};
+
+static void
+chained_finalizer (void *obj, void *data)
+{
+  struct scm_t_chained_finalizer *chained_data = data;
+  if (chained_data->resuscitating_p)
+    {
+      if (chained_data->prev)
+        scm_i_set_finalizer (obj, chained_data->prev, chained_data->prev_data);
+      chained_data->proc (obj, chained_data->data);
+    }
+  else
+    {
+      chained_data->proc (obj, chained_data->data);
+      if (chained_data->prev)
+        chained_data->prev (obj, chained_data->prev_data);
+    }
+}
+
+void
+scm_i_add_resuscitator (void *obj, scm_t_finalizer_proc proc, void *data)
+{
+  struct scm_t_chained_finalizer *chained_data;
+  chained_data = scm_gc_malloc (sizeof (*chained_data), "chained finalizer");
+  chained_data->resuscitating_p = 1;
+  chained_data->proc = proc;
+  chained_data->data = data;
+  GC_REGISTER_FINALIZER_NO_ORDER (obj, chained_finalizer, chained_data,
+                                  &chained_data->prev,
+                                  &chained_data->prev_data);
+}
+
+static void
+shuffle_resuscitators_to_front (struct scm_t_chained_finalizer *cd)
+{
+  while (cd->prev == chained_finalizer)
+    {
+      struct scm_t_chained_finalizer *prev = cd->prev_data;
+      scm_t_finalizer_proc proc = cd->proc;
+      void *data = cd->data;
+
+      if (!prev->resuscitating_p)
+        break;
+
+      cd->resuscitating_p = 1;
+      cd->proc = prev->proc;
+      cd->data = prev->data;
+
+      prev->resuscitating_p = 0;
+      prev->proc = proc;
+      prev->data = data;
+
+      cd = prev;
+    }
+}
+
+void
+scm_i_add_finalizer (void *obj, scm_t_finalizer_proc proc, void *data)
+{
+  struct scm_t_chained_finalizer *chained_data;
+  chained_data = scm_gc_malloc (sizeof (*chained_data), "chained finalizer");
+  chained_data->resuscitating_p = 0;
+  chained_data->proc = proc;
+  chained_data->data = data;
+  GC_REGISTER_FINALIZER_NO_ORDER (obj, chained_finalizer, chained_data,
+                                  &chained_data->prev,
+                                  &chained_data->prev_data);
+  shuffle_resuscitators_to_front (chained_data);
+}
+
+
+
+
+void
+scm_init_finalizers (void)
+{
+}

libguile/finalizers.h

@@ -0,0 +1,39 @@
+#ifndef SCM_FINALIZERS_H
+#define SCM_FINALIZERS_H
+
+/* Copyright (C) 2012 Free Software Foundation, Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public License
+ * as published by the Free Software Foundation; either version 3 of
+ * the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301 USA
+ */
+
+
+
+#include "libguile/__scm.h"
+
+
+
+typedef void (*scm_t_finalizer_proc) (void *obj, void *data);
+
+SCM_INTERNAL void scm_i_set_finalizer (void *obj, scm_t_finalizer_proc,
+                                       void *data);
+SCM_INTERNAL void scm_i_add_finalizer (void *obj, scm_t_finalizer_proc,
+                                       void *data);
+SCM_INTERNAL void scm_i_add_resuscitator (void *obj, scm_t_finalizer_proc,
+                                          void *data);
+
+SCM_INTERNAL void scm_init_finalizers (void);
+
+#endif  /* SCM_FINALIZERS_H */