From 0b77014f0c7d53b8bdbc7059c92f526560e1cacd Mon Sep 17 00:00:00 2001
From: Andy Wingo <wingo@pobox.com>
Date: Thu, 16 Jun 2011 19:35:14 +0200
Subject: [PATCH] fix initial values of reallocated fluids

* libguile/threads.h:
* libguile/threads.c (scm_i_reset_fluid): New internal function, resets
  the binding of a fluid for all threads.  Needed for fluid GC.

* libguile/fluids.c (new_fluid): Call scm_i_reset_fluid here.
---
 libguile/fluids.c  |  5 +++++
 libguile/threads.c | 18 ++++++++++++++++++
 libguile/threads.h |  1 +
 3 files changed, 24 insertions(+)

diff --git a/libguile/fluids.c b/libguile/fluids.c
index f42c0a484..67efd9f6a 100644
--- a/libguile/fluids.c
+++ b/libguile/fluids.c
@@ -163,6 +163,11 @@ new_fluid ()
 					 SCM2PTR (fluid));
 
   scm_dynwind_end ();
+
+  /* Now null out values.  We could (and probably should) do this when
+     the fluid is collected instead of now.  */
+  scm_i_reset_fluid (n, SCM_BOOL_F);
+
   return fluid;
 }
 
diff --git a/libguile/threads.c b/libguile/threads.c
index 64807f8c0..97d9f6497 100644
--- a/libguile/threads.c
+++ b/libguile/threads.c
@@ -484,6 +484,24 @@ static int thread_count;
 
 static SCM scm_i_default_dynamic_state;
 
+/* Run when a fluid is collected.  */
+void
+scm_i_reset_fluid (size_t n, SCM val)
+{
+  scm_i_thread *t;
+
+  scm_i_pthread_mutex_lock (&thread_admin_mutex);
+  for (t = all_threads; t; t = t->next_thread)
+    if (SCM_I_DYNAMIC_STATE_P (t->dynamic_state))
+      {
+        SCM v = SCM_I_DYNAMIC_STATE_FLUIDS (t->dynamic_state);
+          
+        if (n < SCM_SIMPLE_VECTOR_LENGTH (v))
+          SCM_SIMPLE_VECTOR_SET (v, n, val);
+      }
+  scm_i_pthread_mutex_unlock (&thread_admin_mutex);
+}
+
 /* Perform first stage of thread initialisation, in non-guile mode.
  */
 static void
diff --git a/libguile/threads.h b/libguile/threads.h
index 609262a19..edecad819 100644
--- a/libguile/threads.h
+++ b/libguile/threads.h
@@ -136,6 +136,7 @@ SCM_API SCM scm_spawn_thread (scm_t_catch_body body, void *body_data,
 SCM_API void *scm_without_guile (void *(*func)(void *), void *data);
 SCM_API void *scm_with_guile (void *(*func)(void *), void *data);
 
+SCM_INTERNAL void scm_i_reset_fluid (size_t, SCM);
 SCM_INTERNAL void scm_threads_prehistory (void *);
 SCM_INTERNAL void scm_init_threads (void);
 SCM_INTERNAL void scm_init_thread_procs (void);
-- 
2.20.1