variables: add helper function when adding/removing variable callbacks

src/misc/variables.c

@@ -804,36 +804,15 @@ int var_Get( vlc_object_t *p_this, const char *psz_name, vlc_value_t *p_val )
     return var_GetChecked( p_this, psz_name, 0, p_val );
 }
 
-#undef var_AddCallback
-/**
- * Register a callback in a variable
- *
- * We store a function pointer that will be called upon variable
- * modification.
- *
- * \param p_this The object that holds the variable
- * \param psz_name The name of the variable
- * \param pf_callback The function pointer
- * \param p_data A generic pointer that will be passed as the last
- *               argument to the callback function.
- *
- * \warning The callback function is run in the thread that calls var_Set on
- *          the variable. Use proper locking. This thread may not have much
- *          time to spare, so keep callback functions short.
- */
-int var_AddCallback( vlc_object_t *p_this, const char *psz_name,
-                     vlc_callback_t pf_callback, void *p_data )
+static int AddCallback( vlc_object_t *p_this, const char *psz_name,
+                        callback_entry_t entry )
 {
     variable_t *p_var;
-    callback_entry_t entry;
 
     assert( p_this );
 
     vlc_object_internals_t *p_priv = vlc_internals( p_this );
 
-    entry.pf_callback = pf_callback;
-    entry.p_data = p_data;
-
     vlc_mutex_lock( &p_priv->var_lock );
 
     p_var = Lookup( p_this, psz_name );
@@ -841,7 +820,7 @@ int var_AddCallback( vlc_object_t *p_this, const char *psz_name,
     {
         vlc_mutex_unlock( &p_priv->var_lock );
         msg_Err( p_this, "cannot add callback %p to nonexistent "
-                         "variable '%s'", pf_callback, psz_name );
+                         "variable '%s'", entry.pf_callback, psz_name );
         return VLC_ENOVAR;
     }
 
@@ -856,15 +835,35 @@ int var_AddCallback( vlc_object_t *p_this, const char *psz_name,
     return VLC_SUCCESS;
 }
 
-#undef var_DelCallback
+#undef var_AddCallback
 /**
- * Remove a callback from a variable
+ * Register a callback in a variable
  *
- * pf_callback and p_data have to be given again, because different objects
- * might have registered the same callback function.
+ * We store a function pointer that will be called upon variable
+ * modification.
+ *
+ * \param p_this The object that holds the variable
+ * \param psz_name The name of the variable
+ * \param pf_callback The function pointer
+ * \param p_data A generic pointer that will be passed as the last
+ *               argument to the callback function.
+ *
+ * \warning The callback function is run in the thread that calls var_Set on
+ *          the variable. Use proper locking. This thread may not have much
+ *          time to spare, so keep callback functions short.
  */
-int var_DelCallback( vlc_object_t *p_this, const char *psz_name,
+int var_AddCallback( vlc_object_t *p_this, const char *psz_name,
                      vlc_callback_t pf_callback, void *p_data )
+{
+    callback_entry_t entry;
+    entry.pf_callback = pf_callback;
+    entry.p_data = p_data;
+
+    return AddCallback(p_this, psz_name, entry);
+}
+
+static int DelCallback( vlc_object_t *p_this, const char *psz_name,
+                        callback_entry_t entry )
 {
     int i_entry;
     variable_t *p_var;
@@ -889,13 +888,13 @@ int var_DelCallback( vlc_object_t *p_this, const char *psz_name,
 
     for( i_entry = p_var->i_entries ; i_entry-- ; )
     {
-        if( p_var->p_entries[i_entry].pf_callback == pf_callback
-            && p_var->p_entries[i_entry].p_data == p_data )
+        if( p_var->p_entries[i_entry].pf_callback == entry.pf_callback
+            && p_var->p_entries[i_entry].p_data == entry.p_data )
         {
             break;
         }
 #ifndef NDEBUG
-        else if( p_var->p_entries[i_entry].pf_callback == pf_callback )
+        else if( p_var->p_entries[i_entry].pf_callback == entry.pf_callback )
             b_found_similar = true;
 #endif
     }
@@ -919,6 +918,23 @@ int var_DelCallback( vlc_object_t *p_this, const char *psz_name,
     return VLC_SUCCESS;
 }
 
+#undef var_DelCallback
+/**
+ * Remove a callback from a variable
+ *
+ * pf_callback and p_data have to be given again, because different objects
+ * might have registered the same callback function.
+ */
+int var_DelCallback( vlc_object_t *p_this, const char *psz_name,
+                     vlc_callback_t pf_callback, void *p_data )
+{
+    callback_entry_t entry;
+    entry.pf_callback = pf_callback;
+    entry.p_data = p_data;
+
+    return DelCallback(p_this, psz_name, entry);
+}
+
 #undef var_TriggerCallback
 /**
  * Trigger callback on a variable