[vlc-devel] commit: Improve the still really dumb reference checker ( Rémi Denis-Courmont )
git version control
git at videolan.org
Fri May 30 17:16:25 CEST 2008
vlc | branch: master | Rémi Denis-Courmont <rem at videolan.org> | Fri May 30 18:14:25 2008 +0300| [234a17d087d4b5648adb9051a847db31bbc47149]
Improve the still really dumb reference checker
> http://git.videolan.org/gitweb.cgi/vlc.git/?a=commit;h=234a17d087d4b5648adb9051a847db31bbc47149
---
src/libvlc.h | 3 ++
src/misc/objects.c | 75 ++++++++++++++++++++++++++++++++++------------------
2 files changed, 52 insertions(+), 26 deletions(-)
diff --git a/src/libvlc.h b/src/libvlc.h
index 9160eb7..fd83455 100644
--- a/src/libvlc.h
+++ b/src/libvlc.h
@@ -187,6 +187,9 @@ struct vlc_object_internals_t
vlc_spinlock_t ref_spin;
unsigned i_refcount;
vlc_destructor_t pf_destructor;
+#ifndef NDEBUG
+ vlc_thread_t creator_id;
+#endif
/* Objects tree structure */
vlc_object_t *prev, *next;
diff --git a/src/misc/objects.c b/src/misc/objects.c
index 9c5cdbf..e717aaf 100644
--- a/src/misc/objects.c
+++ b/src/misc/objects.c
@@ -171,6 +171,13 @@ void *vlc_custom_create( vlc_object_t *p_this, size_t i_size,
p_priv->pipes[0] = p_priv->pipes[1] = -1;
p_priv->next = VLC_OBJECT (p_libvlc_global);
+#if defined (NDEBUG)
+ /* ... */
+#elif defined (LIBVLC_USE_PTRHEAD)
+ p_priv->creator_id = pthread_self ();
+#elif defined (WIN32)
+ p_priv->creator_id = GetCurrentThreadId ();
+#endif
vlc_mutex_lock( &structure_lock );
p_priv->prev = vlc_internals (p_libvlc_global)->prev;
vlc_internals (p_libvlc_global)->prev = p_new;
@@ -1481,28 +1488,47 @@ static void ListChildren( vlc_list_t *p_list, vlc_object_t *p_this, int i_type )
}
#ifndef NDEBUG
+# ifdef __GLIBC__
+# include <execinfo.h>
+# endif
+
void vlc_refcheck (vlc_object_t *obj)
{
static unsigned errors = 0;
- vlc_object_t *caller = vlc_threadobj ();
- vlc_object_internals_t *priv = vlc_internals (obj);
- int refs;
-
if (errors > 100)
return;
- if (!caller)
- return; /* main thread, not sure how to handle it */
+ /* Anyone can use the root object (though it should not exist) */
+ if (obj == VLC_OBJECT (vlc_global ()))
+ return;
- /* An object can always access itself without reference! */
+ /* Anyone can use its libvlc instance object */
+ if (obj == VLC_OBJECT (obj->p_libvlc))
+ return;
+
+ /* The thread that created the object holds the initial reference */
+ vlc_object_internals_t *priv = vlc_internals (obj);
+#if defined (LIBVLC_USE_PTHREAD)
+ if (pthread_equal (priv->creator_id, pthread_self ()))
+#elif defined WIN32
+ if (priv->creator_id == GetCurrentThreadId ())
+#else
+ if (0)
+#endif
+ return;
+
+ /* A thread can use its own object without reference! */
+ vlc_object_t *caller = vlc_threadobj ();
if (caller == obj)
return;
/* The calling thread is younger than the object.
- * Access could be valid, we would need more accounting. */
- if (caller->i_object_id > obj->i_object_id)
+ * Access could be valid through cross-thread synchronization;
+ * we would need better accounting. */
+ if (caller && (caller->i_object_id > obj->i_object_id))
return;
+ int refs;
vlc_spin_lock (&priv->ref_spin);
refs = priv->i_refcount;
vlc_spin_unlock (&priv->ref_spin);
@@ -1512,25 +1538,22 @@ void vlc_refcheck (vlc_object_t *obj)
if (refs > 1)
return;
- /* The parent of an object normally holds the unique reference.
- * As not all objects are threads, it could also be an ancestor. */
- vlc_mutex_lock (&structure_lock);
- for (vlc_object_t *cur = obj; cur != NULL; cur = cur->p_parent)
- if (cur == caller)
- {
- vlc_mutex_unlock (&structure_lock);
- return;
- }
- vlc_mutex_unlock (&structure_lock);
-
-#if 1
- if (caller->i_object_type == VLC_OBJECT_PLAYLIST)
- return; /* Playlist is too clever, or hopelessly broken. */
+ fprintf (stderr, "The %s %s thread object is accessing...\n"
+ "the %s %s object in a suspicous manner.\n",
+ caller && caller->psz_object_name
+ ? caller->psz_object_name : "unnamed",
+ caller ? caller->psz_object_type : "main",
+ obj->psz_object_name ? obj->psz_object_name : "unnamed",
+ obj->psz_object_type);
+ fflush (stderr);
+
+#ifdef __GLIBC__
+ void *stack[20];
+ int stackdepth = backtrace (stack, sizeof (stack) / sizeof (stack[0]));
+ backtrace_symbols_fd (stack, stackdepth, 2);
#endif
- msg_Err (caller, "This thread is accessing...");
- msg_Err (obj, "...this object in a suspicious manner.");
if (++errors == 100)
- msg_Err (caller, "Too many reference errors");
+ fprintf (stderr, "Too many reference errors!\n");
}
#endif
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