PyAPI: Fix memory leak of parameters used for python 'draw_callbacks'

When closing the blender, while the callbacks are removed, the
reference count of the object used as `customdata` is not decremented.

This commit adds two functions that correctly release the
python `draw_callbacks` before releasing all `draw_callbacks`.

Differential Revision: https://developer.blender.org/D10478

1 files changed, 16 insertions, 0 deletions

diff --git a/source/blender/editors/space_api/spacetypes.c b/source/blender/editors/space_api/spacetypes.c
index 817760615df..c112c678a09 100644
--- a/source/blender/editors/space_api/spacetypes.c
+++ b/source/blender/editors/space_api/spacetypes.c
@@ -272,6 +272,22 @@ void ED_region_draw_cb_draw(const bContext *C, ARegion *region, int type)
   }
 }
 
+void ED_region_draw_cb_remove_by_type(ARegionType *art, void *draw_fn, void (*free)(void *))
+{
+  RegionDrawCB *rdc = art->drawcalls.first;
+  while (rdc) {
+    RegionDrawCB *rdc_next = rdc->next;
+    if (rdc->draw == draw_fn) {
+      if (free) {
+        free(rdc->customdata);
+      }
+      BLI_remlink(&art->drawcalls, rdc);
+      MEM_freeN(rdc);
+    }
+    rdc = rdc_next;
+  }
+}
+
 /* ********************* space template *********************** */
 /* forward declare */
 void ED_spacetype_xxx(void);