Cleaner fix to the "object is not attached" issue with modules loaded from cache

 which weren't used by VLC. This now adds a new b_used flag to module_cache_t which is set to VLC_TRUE once we know that the cached version of the plugin is usable (and thus gets attached to something). If it's not usable, it wont be attached so we tell ModuleDelete() not to try dettaching it.

src/misc/modules.c

@@ -137,7 +137,7 @@ static int  AllocatePluginFile  ( vlc_object_t *, char *, int64_t, int64_t );
 static module_t * AllocatePlugin( vlc_object_t *, char * );
 #endif
 static int  AllocateBuiltinModule( vlc_object_t *, int ( * ) ( module_t * ) );
-static int  DeleteModule ( module_t * );
+static int  DeleteModule ( module_t *, vlc_bool_t );
 #ifdef HAVE_DYNAMIC_PLUGINS
 static void   DupModule        ( module_t * );
 static void   UndupModule      ( module_t * );
@@ -263,7 +263,7 @@ void __module_EndBank( vlc_object_t *p_this )
     {
         if( p_bank->pp_loaded_cache[p_bank->i_loaded_cache] )
         {
-            DeleteModule( p_bank->pp_loaded_cache[p_bank->i_loaded_cache]->p_module );
+            DeleteModule( p_bank->pp_loaded_cache[p_bank->i_loaded_cache]->p_module, p_bank->pp_loaded_cache[p_bank->i_loaded_cache]->b_used );
             free( p_bank->pp_loaded_cache[p_bank->i_loaded_cache]->psz_file );
             free( p_bank->pp_loaded_cache[p_bank->i_loaded_cache] );
             p_bank->pp_loaded_cache[p_bank->i_loaded_cache] = NULL;
@@ -294,7 +294,7 @@ void __module_EndBank( vlc_object_t *p_this )
     {
         p_next = (module_t *)p_this->p_libvlc_global->p_module_bank->pp_children[0];
 
-        if( DeleteModule( p_next ) )
+        if( DeleteModule( p_next, VLC_TRUE ) )
         {
             /* Module deletion failed */
             msg_Err( p_this, "module \"%s\" can't be removed, trying harder",
@@ -639,7 +639,7 @@ found_shortcut:
             {
                 CacheMerge( p_this, p_module, p_new_module );
                 vlc_object_attach( p_new_module, p_module );
-                DeleteModule( p_new_module );
+                DeleteModule( p_new_module, VLC_TRUE );
             }
         }
 #endif
@@ -1057,12 +1057,12 @@ static int AllocatePluginFile( vlc_object_t * p_this, char * psz_file,
             {
                 if( p_item->pf_callback || p_item->i_action )
                 {
-                    module_t *p_new_module = AllocatePlugin( p_this, psz_file );
-                    vlc_object_attach( p_module, p_new_module );
-                    p_module = p_new_module;
+                    module_t *p_module = AllocatePlugin( p_this, psz_file );
                     break;
                 }
             }
+            if( p_module == p_cache_entry->p_module )
+                p_cache_entry->b_used = VLC_TRUE;
         }
     }
 
@@ -1091,6 +1091,7 @@ static int AllocatePluginFile( vlc_object_t * p_this, char * psz_file,
         p_bank->pp_cache[p_bank->i_cache]->i_time = i_file_time;
         p_bank->pp_cache[p_bank->i_cache]->i_size = i_file_size;
         p_bank->pp_cache[p_bank->i_cache]->b_junk = p_module ? 0 : 1;
+        p_bank->pp_cache[p_bank->i_cache]->b_used = VLC_TRUE;
         p_bank->pp_cache[p_bank->i_cache]->p_module = p_module;
         p_bank->i_cache++;
     }
@@ -1264,10 +1265,11 @@ static int AllocateBuiltinModule( vlc_object_t * p_this,
  *****************************************************************************
  * This function can only be called if the module isn't being used.
  *****************************************************************************/
-static int DeleteModule( module_t * p_module )
+static int DeleteModule( module_t * p_module, vlc_bool_t b_detach )
 {
     if( !p_module ) return VLC_EGENERIC;
-    vlc_object_detach( p_module );
+    if( b_detach )
+        vlc_object_detach( p_module );
 
     /* We free the structures that we strdup()ed in Allocate*Module(). */
 #ifdef HAVE_DYNAMIC_PLUGINS
@@ -1774,6 +1776,7 @@ static void CacheLoad( vlc_object_t *p_this )
         LOAD_IMMEDIATE( pp_cache[i]->i_time );
         LOAD_IMMEDIATE( pp_cache[i]->i_size );
         LOAD_IMMEDIATE( pp_cache[i]->b_junk );
+        pp_cache[i]->b_used = VLC_FALSE;
 
         if( pp_cache[i]->b_junk ) continue;
 
@@ -2216,7 +2219,7 @@ static void CacheMerge( vlc_object_t *p_this, module_t *p_cache,
 }
 
 /*****************************************************************************
- * FindPluginCache: finds the cache entry corresponding to a file
+ * CacheFind: finds the cache entry corresponding to a file
  *****************************************************************************/
 static module_cache_t *CacheFind( vlc_object_t *p_this, char *psz_file,
                                   int64_t i_time, int64_t i_size )

src/misc/modules.h

@@ -67,6 +67,7 @@ struct module_cache_t
 
     /* Optional extra data */
     module_t *p_module;
+    vlc_bool_t b_used;
 };
 
 #define module_InitBank(a)     __module_InitBank(VLC_OBJECT(a))