Remove weak set usage in ports.c

* libguile/ephemerons.h:
* libguile/ephemerons.c (scm_c_ephemeron_load, scm_c_ephemeron_push):
New routines.
* libguile/ioext.c (scm_fdes_to_ports): Rework in terms of
scm_c_port_for_each.
* libguile/ports-internal.h (struct scm_t_port): Add pointer to entry on
weak ports list, so that we can cancel it easily.
* libguile/ports.c (release_port): Mark weak ports list entry as dead.
(all_ports_needing_close, for_each_port_needing_close): Rework as
ephemeron chain.
(scm_c_make_port_with_encoding, close_port, scm_c_port_for_each): Adapt
API.
(scm_init_ports): No more weak set.

libguile/ephemerons.c

@@ -126,6 +126,18 @@ scm_c_ephemeron_next (struct gc_ephemeron *e)
   return gc_ephemeron_chain_next (e);
 }
 
+struct gc_ephemeron*
+scm_c_ephemeron_load (struct gc_ephemeron **loc)
+{
+  return gc_ephemeron_chain_head (loc);
+}
+
+void
+scm_c_ephemeron_push (struct gc_ephemeron **loc, struct gc_ephemeron *e)
+{
+  gc_ephemeron_chain_push (loc, e);
+}
+
 
 
 

libguile/ephemerons.h

@@ -39,6 +39,10 @@ SCM_INTERNAL int scm_i_print_ephemeron (SCM exp, SCM port,
 SCM_INTERNAL struct gc_ephemeron* scm_to_ephemeron (SCM e);
 SCM_INTERNAL SCM scm_from_ephemeron (struct gc_ephemeron *e);
 
+SCM_INTERNAL struct gc_ephemeron* scm_c_ephemeron_load (struct gc_ephemeron **loc);
+SCM_INTERNAL void scm_c_ephemeron_push (struct gc_ephemeron **loc,
+                                        struct gc_ephemeron *e);
+
 SCM_INTERNAL struct scm_ephemeron_table* scm_c_make_ephemeron_table (size_t count);
 SCM_INTERNAL size_t scm_c_ephemeron_table_length (struct scm_ephemeron_table *et);
 SCM_INTERNAL struct gc_ephemeron*

libguile/ioext.c

@@ -1,4 +1,4 @@
-/* Copyright 1995-2001,2003,2006,2011,2014,2018
+/* Copyright 1995-2001,2003,2006,2011,2014,2018,2025
      Free Software Foundation, Inc.
 
    This file is part of Guile.
@@ -282,15 +282,19 @@ SCM_DEFINE (scm_primitive_move_to_fdes, "primitive-move->fdes", 2, 0, 0,
 }
 #undef FUNC_NAME
 
-static SCM
-get_matching_port (void *closure, SCM port, SCM result)
+struct scm_fdes_to_ports_data
 {
-  int fd = * (int *) closure;
-  
-  if (SCM_OPFPORTP (port) && SCM_FSTREAM (port)->fdes == fd)
-    result = scm_cons (port, result);
+  SCM ports;
+  int fd;
+};
 
-  return result;
+static void
+collect_matching_ports (void *closure, SCM port)
+{
+  struct scm_fdes_to_ports_data *data = closure;
+
+  if (SCM_OPFPORTP (port) && SCM_FSTREAM (port)->fdes == data->fd)
+    data->ports = scm_cons (port, data->ports);
 }
 
 /* Return a list of ports using a given file descriptor.  */
@@ -301,13 +305,13 @@ SCM_DEFINE (scm_fdes_to_ports, "fdes->ports", 1, 0, 0,
 	    "counts.")
 #define FUNC_NAME s_scm_fdes_to_ports
 {
-  SCM result = SCM_EOL;
-  int int_fd = scm_to_int (fd);
+  struct scm_fdes_to_ports_data data;
+  data.ports = SCM_EOL;
+  data.fd = scm_to_int (fd);
 
-  result = scm_c_weak_set_fold (get_matching_port,
-                                (void*) &int_fd, result, 
-                                scm_i_port_weak_set);
-  return result;
+  scm_c_port_for_each (collect_matching_ports, &data);
+
+  return data.ports;
 }
 #undef FUNC_NAME    
 

libguile/ports-internal.h

@@ -1,6 +1,6 @@
 /* ports-internal.h - internal-only declarations for ports.
 
-   Copyright 2013,2018
+   Copyright 2013,2018,2025
      Free Software Foundation, Inc.
 
    This file is part of Guile.
@@ -27,6 +27,7 @@
 #include <string.h>
 
 #include "libguile/bytevectors.h"
+#include "libguile/ephemerons.h"
 #include "libguile/list.h"
 #include "libguile/pairs.h"
 #include "libguile/ports.h"
@@ -361,6 +362,12 @@ struct scm_t_port
   iconv_t input_cd;      /* with iconv_lock */
   iconv_t output_cd;     /* with iconv_lock */
 
+  /* If the port needs to be closed when it becomes unreachable, it is
+     put on a global ephemeron chain, so that we can explicitly flush
+     all ports.  If the port is later closed manually, we can mark that
+     chain link as dead, and it will be collected on the next GC.  */
+  struct gc_ephemeron *close_handle;
+
   /* Port properties.  */
   SCM alist;
 };

libguile/ports.c

@@ -159,6 +159,13 @@ release_port (SCM port)
   if (cur > 1)
     return;
 
+  struct gc_ephemeron *e = pt->close_handle;
+  if (e)
+    {
+      pt->close_handle = NULL;
+      scm_c_ephemeron_mark_dead_x (e);
+    }
+
   /* FIXME: `catch' around the close call?  It could throw an exception,
      and in that case we'd leak the iconv descriptors, if any.  */
   if (SCM_PORT_TYPE (port)->close)
@@ -701,11 +708,24 @@ SCM_DEFINE (scm_port_mode, "port-mode", 1, 0, 0,
 
 
 
-/* The port table --- a weak set of all ports.
+/* The port list --- a weak list of all ports.
 
    We need a global registry of ports to flush them all at exit, and to
    get all the ports matching a file descriptor.  */
-SCM scm_i_port_weak_set;
+static struct gc_ephemeron *all_ports_needing_close = NULL;
+
+static void
+for_each_port_needing_close (void (*proc)(void *data, SCM p), void *data)
+{
+  for (struct gc_ephemeron *e = scm_c_ephemeron_load (&all_ports_needing_close);
+       e;
+       e = scm_c_ephemeron_next (e))
+    {
+      SCM port = scm_c_ephemeron_key (e);
+      if (!scm_is_false (port))
+        proc (data, port);
+    }
+}
 
 
 
@@ -798,7 +818,8 @@ scm_c_make_port_with_encoding (scm_t_port_type *ptob, unsigned long mode_bits,
   if (SCM_PORT_TYPE (ret)->flags & SCM_PORT_TYPE_NEEDS_CLOSE_ON_GC)
     {
       scm_i_add_port_finalizer (SCM_I_CURRENT_THREAD, ret);
-      scm_weak_set_add_x (scm_i_port_weak_set, ret);
+      pt->close_handle = scm_c_make_ephemeron (ret, SCM_BOOL_T);
+      scm_c_ephemeron_push (&all_ports_needing_close, pt->close_handle);
     }
 
   initialize_port_buffers (ret);
@@ -901,9 +922,6 @@ close_port (SCM port, int explicit)
 
   SCM_CLR_PORT_OPEN_FLAG (port);
 
-  if (SCM_PORT_TYPE (port)->flags & SCM_PORT_TYPE_NEEDS_CLOSE_ON_GC)
-    scm_weak_set_remove_x (scm_i_port_weak_set, port);
-
   release_port (port);
 
   return SCM_BOOL_T;
@@ -4059,32 +4077,10 @@ scm_port_print (SCM exp, SCM port, scm_print_state *pstate SCM_UNUSED)
 
 /* Iterating over all ports.  */
 
-struct for_each_data 
-{
-  void (*proc) (void *data, SCM p);
-  void *data;
-};
-
-static SCM
-for_each_trampoline (void *data, SCM port, SCM result)
-{
-  struct for_each_data *d = data;
-  
-  d->proc (d->data, port);
-
-  return result;
-}
-
 void
 scm_c_port_for_each (void (*proc)(void *data, SCM p), void *data)
 {
-  struct for_each_data d;
-  
-  d.proc = proc;
-  d.data = data;
-
-  scm_c_weak_set_fold (for_each_trampoline, &d, SCM_EOL,
-                       scm_i_port_weak_set);
+  for_each_port_needing_close (proc, data);
 }
 
 static void
@@ -4230,8 +4226,6 @@ scm_init_ports (void)
   scm_void_port_type = scm_make_port_type ("void", void_port_read,
 					   void_port_write);
 
-  scm_i_port_weak_set = scm_c_make_weak_set (31);
-
   cur_inport_fluid = scm_make_fluid ();
   cur_outport_fluid = scm_make_fluid ();
   cur_errport_fluid = scm_make_fluid ();

libguile/ports.h

@@ -27,11 +27,6 @@
 #include "libguile/print.h"
 #include "libguile/strings.h"
 
-
-
-SCM_INTERNAL SCM scm_i_port_weak_set;
-
-
 
 
 #define SCM_EOF_OBJECT_P(x) (scm_is_eq ((x), SCM_EOF_VAL))