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, 13 insertions, 17 deletions

diff --git a/source/blender/editors/space_topbar/space_topbar.c b/source/blender/editors/space_topbar/space_topbar.c
index dc357cdd355..be249699d57 100644
--- a/source/blender/editors/space_topbar/space_topbar.c
+++ b/source/blender/editors/space_topbar/space_topbar.c
@@ -129,12 +129,11 @@ static void topbar_header_region_init(wmWindowManager *UNUSED(wm), ARegion *regi
   ED_region_header_init(region);
 }
 
-static void topbar_main_region_listener(wmWindow *UNUSED(win),
-                                        ScrArea *UNUSED(area),
-                                        ARegion *region,
-                                        wmNotifier *wmn,
-                                        const Scene *UNUSED(scene))
+static void topbar_main_region_listener(wmRegionListenerParams *params)
 {
+  ARegion *region = params->region;
+  wmNotifier *wmn = params->notifier;
+
   /* context changes */
   switch (wmn->category) {
     case NC_WM:
@@ -160,12 +159,11 @@ static void topbar_main_region_listener(wmWindow *UNUSED(win),
   }
 }
 
-static void topbar_header_listener(wmWindow *UNUSED(win),
-                                   ScrArea *UNUSED(area),
-                                   ARegion *region,
-                                   wmNotifier *wmn,
-                                   const Scene *UNUSED(scene))
+static void topbar_header_listener(wmRegionListenerParams *params)
 {
+  ARegion *region = params->region;
+  wmNotifier *wmn = params->notifier;
+
   /* context changes */
   switch (wmn->category) {
     case NC_WM:
@@ -191,14 +189,12 @@ static void topbar_header_listener(wmWindow *UNUSED(win),
   }
 }
 
-static void topbar_header_region_message_subscribe(const struct bContext *UNUSED(C),
-                                                   struct WorkSpace *workspace,
-                                                   struct Scene *UNUSED(scene),
-                                                   struct bScreen *UNUSED(screen),
-                                                   struct ScrArea *UNUSED(area),
-                                                   struct ARegion *region,
-                                                   struct wmMsgBus *mbus)
+static void topbar_header_region_message_subscribe(wmRegionMessageSubscribeParams *params)
 {
+  struct wmMsgBus *mbus = params->message_bus;
+  WorkSpace *workspace = params->workspace;
+  ARegion *region = params->region;
+
   wmMsgSubscribeValue msg_sub_value_region_tag_redraw = {
       .owner = region,
       .user_data = region,