Reference count libvlc. API break.

include/vlc/libvlc.h

@@ -102,7 +102,7 @@ libvlc_exception_get_message( const libvlc_exception_t *p_exception );
  */
 
 /**
- * Create an initialized libvlc instance
+ * Create an initialized libvlc instance.
  * \param argc the number of arguments
  * \param argv command-line-type arguments
  * \param exception an initialized exception pointer
@@ -119,10 +119,17 @@ libvlc_new( int , const char *const *, libvlc_exception_t *);
 VLC_PUBLIC_API int libvlc_get_vlc_id( libvlc_instance_t *p_instance );
 
 /**
- * Destroy a libvlc instance.
+ * Decrements the reference count of a libvlc instance, and destroys it
+ * if it reaches zero.
  * \param p_instance the instance to destroy
  */
-VLC_PUBLIC_API void libvlc_destroy( libvlc_instance_t *, libvlc_exception_t * );
+VLC_PUBLIC_API void libvlc_release( libvlc_instance_t *, libvlc_exception_t * );
+
+/**
+ * Increments the reference count of a libvlc instance.
+ * The reference count is initially one when libvlc_new() returns.
+ */
+VLC_PUBLIC_API void libvlc_retain( libvlc_instance_t * );
 
 /** @}*/
 

src/control/core.c

@@ -20,12 +20,15 @@
  * along with this program; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  *****************************************************************************/
-#include <stdarg.h>
 #include "libvlc_internal.h"
 #include <vlc/libvlc.h>
 
 #include <vlc_interface.h>
 
+#include <stdarg.h>
+#include <limits.h>
+#include <assert.h>
+
 static const char nomemstr[] = "Insufficient memory";
 
 /*************************************************************************
@@ -106,6 +109,7 @@ libvlc_instance_t * libvlc_new( int argc, const char *const *argv,
     p_new->p_libvlc_int = p_libvlc_int;
     p_new->p_vlm = NULL;
     p_new->b_playlist_locked = 0;
+    p_new->ref_count = 1;
     p_new->p_callback_list = NULL;
     vlc_mutex_init(p_libvlc_int, &p_new->instance_lock);
     vlc_mutex_init(p_libvlc_int, &p_new->event_callback_lock);
@@ -115,14 +119,37 @@ libvlc_instance_t * libvlc_new( int argc, const char *const *argv,
     return p_new;
 }
 
-void libvlc_destroy( libvlc_instance_t *p_instance, libvlc_exception_t *p_e )
+void libvlc_retain( libvlc_instance_t *p_instance )
+{
+    assert( p_instance != NULL );
+    assert( p_instance->ref_count < UINT_MAX );
+
+    vlc_mutex_lock( &p_instance->instance_lock );
+    p_instance->ref_count++;
+    vlc_mutex_unlock( &p_instance->instance_lock );
+}
+
+void libvlc_release( libvlc_instance_t *p_instance, libvlc_exception_t *p_e )
 {
-    libvlc_event_fini( p_instance, p_e );
-    vlc_mutex_destroy( &p_instance->instance_lock );
-    vlc_mutex_destroy( &p_instance->event_callback_lock);
-    libvlc_InternalCleanup( p_instance->p_libvlc_int );
-    libvlc_InternalDestroy( p_instance->p_libvlc_int, VLC_FALSE );
-    free( p_instance );
+    vlc_mutex_t *lock = &p_instance->instance_lock;
+    int refs;
+
+    assert( p_instance->ref_count > 0 );
+
+    vlc_mutex_lock( &p_instance->instance_lock );
+    refs = --p_instance->ref_count;
+    if( refs == 0 )
+        libvlc_event_fini( p_instance, p_e );
+    vlc_mutex_unlock( &p_instance->instance_lock );
+
+    if( refs == 0 )
+    {
+        vlc_mutex_destroy( &p_instance->instance_lock );
+        vlc_mutex_destroy( &p_instance->event_callback_lock );
+        libvlc_InternalCleanup( p_instance->p_libvlc_int );
+        libvlc_InternalDestroy( p_instance->p_libvlc_int, VLC_FALSE );
+        free( p_instance );
+    }
 }
 
 int libvlc_get_vlc_id( libvlc_instance_t *p_instance )

src/control/libvlc_internal.h

@@ -67,6 +67,7 @@ struct libvlc_instance_t
     libvlc_int_t *p_libvlc_int;
     vlm_t        *p_vlm;
     int           b_playlist_locked;
+    unsigned      ref_count;
     vlc_mutex_t   instance_lock;
     vlc_mutex_t   event_callback_lock;
     struct libvlc_callback_entry_list_t *p_callback_list;

src/control/mediacontrol_core.c

@@ -88,7 +88,7 @@ mediacontrol_exit( mediacontrol_Instance *self )
     libvlc_exception_t ex;
     libvlc_exception_init( &ex );
 
-    libvlc_destroy( self->p_instance, &ex );
+    libvlc_release( self->p_instance, &ex );
 }
 
 libvlc_instance_t*

src/control/testapi.c

@@ -74,7 +74,10 @@ int main (int argc, char *argv[])
     libvlc_playlist_clear (vlc, &ex);
     catch ();
 
-    libvlc_destroy (vlc, &ex);
+    libvlc_retain (vlc);
+    libvlc_release (vlc, &ex);
+    catch ();
+    libvlc_release (vlc, &ex);
     catch ();
     return 0;
 }