From e4b90f498c3141ba203a6359a8a0cfe790324203 Mon Sep 17 00:00:00 2001
From: Mark H Weaver <mhw@netris.org>
Date: Sun, 17 Nov 2013 04:00:29 -0500
Subject: [PATCH 1/6] Add mutex locking functions that also block asyncs.

* libguile/async.h (scm_i_pthread_mutex_lock_with_asyncs,
  scm_i_pthread_mutex_unlock_with_asyncs): New macros.

* libguile/threads.c (do_unlock_with_asyncs): New static helper.
  (scm_i_dynwind_pthread_mutex_lock_with_asyncs): New function.

* libguile/threads.h (scm_i_dynwind_pthread_mutex_lock_with_asyncs):
  Add prototype.
---
 libguile/async.h   |   16 ++++++++++++++++
 libguile/threads.c |   16 ++++++++++++++++
 libguile/threads.h |    1 +
 3 files changed, 33 insertions(+), 0 deletions(-)

diff --git a/libguile/async.h b/libguile/async.h
index ceb2b96..a909c0d 100644
--- a/libguile/async.h
+++ b/libguile/async.h
@@ -78,6 +78,22 @@ SCM_API void scm_critical_section_end (void);
     scm_async_click ();						\
   } while (0)
 
+# define scm_i_pthread_mutex_lock_with_asyncs(m)    \
+  do                                                \
+    {                                               \
+      SCM_I_CURRENT_THREAD->block_asyncs++;         \
+      scm_i_pthread_mutex_lock (m);                 \
+    }                                               \
+  while (0)
+
+# define scm_i_pthread_mutex_unlock_with_asyncs(m)  \
+  do                                                \
+    {                                               \
+      scm_i_pthread_mutex_unlock (m);               \
+      SCM_I_CURRENT_THREAD->block_asyncs--;         \
+    }                                               \
+  while (0)
+
 #else /* !BUILDING_LIBGUILE */
 
 # define SCM_CRITICAL_SECTION_START  scm_critical_section_start ()
diff --git a/libguile/threads.c b/libguile/threads.c
index 8cbe1e2..6aeaeb9 100644
--- a/libguile/threads.c
+++ b/libguile/threads.c
@@ -2010,6 +2010,22 @@ scm_pthread_cond_timedwait (scm_i_pthread_cond_t *cond,
 
 #endif
 
+static void
+do_unlock_with_asyncs (void *data)
+{
+  scm_i_pthread_mutex_unlock ((scm_i_pthread_mutex_t *)data);
+  SCM_I_CURRENT_THREAD->block_asyncs--;
+}
+
+void
+scm_i_dynwind_pthread_mutex_lock_with_asyncs (scm_i_pthread_mutex_t *mutex)
+{
+  SCM_I_CURRENT_THREAD->block_asyncs++;
+  scm_i_scm_pthread_mutex_lock (mutex);
+  scm_dynwind_unwind_handler (do_unlock_with_asyncs, mutex,
+                              SCM_F_WIND_EXPLICITLY);
+}
+
 unsigned long
 scm_std_usleep (unsigned long usecs)
 {
diff --git a/libguile/threads.h b/libguile/threads.h
index 901c37b..5a2afa2 100644
--- a/libguile/threads.h
+++ b/libguile/threads.h
@@ -143,6 +143,7 @@ SCM_INTERNAL void scm_init_threads (void);
 SCM_INTERNAL void scm_init_thread_procs (void);
 SCM_INTERNAL void scm_init_threads_default_dynamic_state (void);
 
+SCM_INTERNAL void scm_i_dynwind_pthread_mutex_lock_with_asyncs (scm_i_pthread_mutex_t *mutex);
 
 #define SCM_THREAD_SWITCHING_CODE \
   do { } while (0)
-- 
1.7.5.4