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, 8 insertions, 12 deletions

diff --git a/source/blender/editors/space_statusbar/space_statusbar.c b/source/blender/editors/space_statusbar/space_statusbar.c
index ae56b111360..bf7535f5448 100644
--- a/source/blender/editors/space_statusbar/space_statusbar.c
+++ b/source/blender/editors/space_statusbar/space_statusbar.c
@@ -95,12 +95,11 @@ static void statusbar_keymap(struct wmKeyConfig *UNUSED(keyconf))
 {
 }
 
-static void statusbar_header_region_listener(wmWindow *UNUSED(win),
-                                             ScrArea *UNUSED(area),
-                                             ARegion *region,
-                                             wmNotifier *wmn,
-                                             const Scene *UNUSED(scene))
+static void statusbar_header_region_listener(wmRegionListenerParams *params)
 {
+  ARegion *region = params->region;
+  wmNotifier *wmn = params->notifier;
+
   /* context changes */
   switch (wmn->category) {
     case NC_SCREEN:
@@ -131,14 +130,11 @@ static void statusbar_header_region_listener(wmWindow *UNUSED(win),
   }
 }
 
-static void statusbar_header_region_message_subscribe(const bContext *UNUSED(C),
-                                                      WorkSpace *UNUSED(workspace),
-                                                      Scene *UNUSED(scene),
-                                                      bScreen *UNUSED(screen),
-                                                      ScrArea *UNUSED(area),
-                                                      ARegion *region,
-                                                      struct wmMsgBus *mbus)
+static void statusbar_header_region_message_subscribe(wmRegionMessageSubscribeParams *params)
 {
+  struct wmMsgBus *mbus = params->message_bus;
+  ARegion *region = params->region;
+
   wmMsgSubscribeValue msg_sub_value_region_tag_redraw = {
       .owner = region,
       .user_data = region,