[glib: 7/9] Release GBinding transform functions also when implicitly unbinding because source/target are finali

[Philip Withnall <pwithnall src gnome org>]

commit 7367c5d367bf28737c9e488823bcf2376aa3f739
Author: Sebastian Dröge <sebastian centricular com>
Date:   Thu Nov 26 12:35:28 2020 +0200

    Release GBinding transform functions also when implicitly unbinding because source/target are finalized
    
    This was inconsistently handled before and only explicit unbinding or
    finalizing the binding would've previously released the transform
    function. If the source/target were finalized while more strong
    references to the binding still existed then the transform function
    would stay alive and only the binding itself would be deactivated.

 gobject/gbinding.c | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)
---
diff --git a/gobject/gbinding.c b/gobject/gbinding.c
index 6e8d95e4b..9a4190a97 100644
--- a/gobject/gbinding.c
+++ b/gobject/gbinding.c
@@ -183,11 +183,7 @@ binding_context_unref (BindingContext *context)
  *
  * The transform functions are released when unbinding but unbinding can happen
  * while the transform functions are currently in use inside the notify callbacks.
- *
- * Note that the transform functions are only released from explicit unbinding
- * or when the binding itself is finalized. Finalizing the source and target
- * while the binding is still alive does not release the transform functions
- * yet. */
+ */
 typedef struct {
   GBindingTransformFunc transform_s2t;
   GBindingTransformFunc transform_t2s;
@@ -374,6 +370,7 @@ weak_unbind (gpointer  user_data,
   GBinding *binding;
   GObject *source, *target;
   gboolean binding_was_removed = FALSE;
+  TransformFunc *transform_func;
 
   binding = g_weak_ref_get (&context->binding);
   if (!binding)
@@ -385,6 +382,8 @@ weak_unbind (gpointer  user_data,
 
   g_mutex_lock (&binding->unbind_lock);
 
+  transform_func = g_steal_pointer (&binding->transform_func);
+
   source = g_weak_ref_get (&context->source);
   target = g_weak_ref_get (&context->target);
 
@@ -399,11 +398,13 @@ weak_unbind (gpointer  user_data,
 
   g_mutex_unlock (&binding->unbind_lock);
 
-  /* Unref source and target after the mutex is unlocked as it might
-   * release the last reference, which then accesses the mutex again */
+  /* Unref source, target and transform_func after the mutex is unlocked as it
+   * might release the last reference, which then accesses the mutex again */
   g_clear_object (&target);
   g_clear_object (&source);
 
+  g_clear_pointer (&transform_func, transform_func_unref);
+
   /* This releases the strong reference we got from the weak ref above */
   g_object_unref (binding);