UI Code Quality: Use "params" struct for area and region callbacks

These functions with many arguments can be unwieldy. Aside from the obvious issues
with rewriting the list of arguments and the opportunities for error and frustration
that presents, the long list of arguments make these systems hard to change. So when
an argument should be added, someone might skip that and add some hack instead.

So, as proposed in T73586#1037210, this patch instead uses a "params" struct for
each of these callbacks.

- Use param argument for `ARegionType.listener`
    - Remove unused window field in region listener
- Use param argument for `SpaceType.listener`
- Use params struct for `ARegionType.message_subscribe`

Differential Revision: https://developer.blender.org/D9750

1 files changed, 26 insertions, 30 deletions

diff --git a/source/blender/editors/space_view3d/space_view3d.c b/source/blender/editors/space_view3d/space_view3d.c
index 34d342ddd94..90d42776277 100644
--- a/source/blender/editors/space_view3d/space_view3d.c
+++ b/source/blender/editors/space_view3d/space_view3d.c
@@ -783,9 +783,12 @@ static void *view3d_main_region_duplicate(void *poin)
   return NULL;
 }
 
-static void view3d_main_region_listener(
-    wmWindow *UNUSED(win), ScrArea *area, ARegion *region, wmNotifier *wmn, const Scene *scene)
+static void view3d_main_region_listener(wmRegionListenerParams *params)
 {
+  ScrArea *area = params->area;
+  ARegion *region = params->region;
+  wmNotifier *wmn = params->notifier;
+  const Scene *scene = params->scene;
   View3D *v3d = area->spacedata.first;
   RegionView3D *rv3d = region->regiondata;
   wmGizmoMap *gzmap = region->gizmo_map;
@@ -1041,14 +1044,13 @@ static void view3d_main_region_listener(
   }
 }
 
-static void view3d_main_region_message_subscribe(const struct bContext *C,
-                                                 struct WorkSpace *UNUSED(workspace),
-                                                 struct Scene *UNUSED(scene),
-                                                 struct bScreen *UNUSED(screen),
-                                                 struct ScrArea *area,
-                                                 struct ARegion *region,
-                                                 struct wmMsgBus *mbus)
+static void view3d_main_region_message_subscribe(wmRegionMessageSubscribeParams *params)
 {
+  struct wmMsgBus *mbus = params->message_bus;
+  const bContext *C = params->context;
+  ScrArea *area = params->area;
+  ARegion *region = params->region;
+
   /* Developer note: there are many properties that impact 3D view drawing,
    * so instead of subscribing to individual properties, just subscribe to types
    * accepting some redundant redraws.
@@ -1163,12 +1165,11 @@ static void view3d_header_region_draw(const bContext *C, ARegion *region)
   ED_region_header(C, region);
 }
 
-static void view3d_header_region_listener(wmWindow *UNUSED(win),
-                                          ScrArea *UNUSED(area),
-                                          ARegion *region,
-                                          wmNotifier *wmn,
-                                          const Scene *UNUSED(scene))
+static void view3d_header_region_listener(wmRegionListenerParams *params)
 {
+  ARegion *region = params->region;
+  wmNotifier *wmn = params->notifier;
+
   /* context changes */
   switch (wmn->category) {
     case NC_SCENE:
@@ -1233,14 +1234,11 @@ static void view3d_header_region_listener(wmWindow *UNUSED(win),
 #endif
 }
 
-static void view3d_header_region_message_subscribe(const struct bContext *UNUSED(C),
-                                                   struct WorkSpace *UNUSED(workspace),
-                                                   struct Scene *UNUSED(scene),
-                                                   struct bScreen *UNUSED(screen),
-                                                   struct ScrArea *UNUSED(area),
-                                                   struct ARegion *region,
-                                                   struct wmMsgBus *mbus)
+static void view3d_header_region_message_subscribe(wmRegionMessageSubscribeParams *params)
 {
+  struct wmMsgBus *mbus = params->message_bus;
+  ARegion *region = params->region;
+
   wmMsgParams_RNA msg_key_params = {{0}};
 
   /* Only subscribe to types. */
@@ -1378,12 +1376,11 @@ static void view3d_buttons_region_layout(const bContext *C, ARegion *region)
   ED_view3d_buttons_region_layout_ex(C, region, NULL);
 }
 
-static void view3d_buttons_region_listener(wmWindow *UNUSED(win),
-                                           ScrArea *UNUSED(area),
-                                           ARegion *region,
-                                           wmNotifier *wmn,
-                                           const Scene *UNUSED(scene))
+static void view3d_buttons_region_listener(wmRegionListenerParams *params)
 {
+  ARegion *region = params->region;
+  wmNotifier *wmn = params->notifier;
+
   /* context changes */
   switch (wmn->category) {
     case NC_ANIMATION:
@@ -1502,11 +1499,10 @@ static void view3d_tools_region_draw(const bContext *C, ARegion *region)
 }
 
 /* area (not region) level listener */
-static void space_view3d_listener(wmWindow *UNUSED(win),
-                                  ScrArea *area,
-                                  struct wmNotifier *wmn,
-                                  Scene *UNUSED(scene))
+static void space_view3d_listener(wmSpaceTypeListenerParams *params)
 {
+  ScrArea *area = params->area;
+  wmNotifier *wmn = params->notifier;
   View3D *v3d = area->spacedata.first;
 
   /* context changes */