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

26 files changed, 375 insertions, 475 deletions

diff --git a/source/blender/blenkernel/BKE_screen.h b/source/blender/blenkernel/BKE_screen.h
index 7b5df98d148..4274d59cb9f 100644
--- a/source/blender/blenkernel/BKE_screen.h
+++ b/source/blender/blenkernel/BKE_screen.h
@@ -67,6 +67,13 @@ struct wmWindowManager;
 
 #define BKE_ST_MAXNAME 64
 
+typedef struct wmSpaceTypeListenerParams {
+  struct wmWindow *window;
+  struct ScrArea *area;
+  struct wmNotifier *notifier;
+  const struct Scene *scene;
+} wmSpaceTypeListenerParams;
+
 typedef struct SpaceType {
   struct SpaceType *next, *prev;
 
@@ -85,10 +92,7 @@ typedef struct SpaceType {
   /* exit is called when the area is hidden or removed */
   void (*exit)(struct wmWindowManager *wm, struct ScrArea *area);
   /* Listeners can react to bContext changes */
-  void (*listener)(struct wmWindow *win,
-                   struct ScrArea *area,
-                   struct wmNotifier *wmn,
-                   struct Scene *scene);
+  void (*listener)(wmSpaceTypeListenerParams *params);
 
   /* called when the mouse moves out of the area */
   void (*deactivate)(struct ScrArea *area);
@@ -134,6 +138,23 @@ typedef struct SpaceType {
 
 /* region types are also defined using spacetypes_init, via a callback */
 
+typedef struct wmRegionListenerParams {
+  struct ScrArea *area; /* Can be NULL when the region is not part of an area. */
+  struct ARegion *region;
+  struct wmNotifier *notifier;
+  const struct Scene *scene;
+} wmRegionListenerParams;
+
+typedef struct wmRegionMessageSubscribeParams {
+  const struct bContext *context;
+  struct wmMsgBus *message_bus;
+  struct WorkSpace *workspace;
+  struct Scene *scene;
+  struct bScreen *screen;
+  struct ScrArea *area;
+  struct ARegion *region;
+} wmRegionMessageSubscribeParams;
+
 typedef struct ARegionType {
   struct ARegionType *next, *prev;
 
@@ -158,19 +179,9 @@ typedef struct ARegionType {
   /* snap the size of the region (can be NULL for no snapping). */
   int (*snap_size)(const struct ARegion *region, int size, int axis);
   /* contextual changes should be handled here */
-  void (*listener)(struct wmWindow *win,
-                   struct ScrArea *area,
-                   struct ARegion *region,
-                   struct wmNotifier *wmn,
-                   const struct Scene *scene);
+  void (*listener)(wmRegionListenerParams *params);
   /* Optional callback to generate subscriptions. */
-  void (*message_subscribe)(const struct bContext *C,
-                            struct WorkSpace *workspace,
-                            struct Scene *scene,
-                            struct bScreen *screen,
-                            struct ScrArea *area,
-                            struct ARegion *region,
-                            struct wmMsgBus *mbus);
+  void (*message_subscribe)(wmRegionMessageSubscribeParams *params);
 
   void (*free)(struct ARegion *);
 
diff --git a/source/blender/editors/include/ED_screen.h b/source/blender/editors/include/ED_screen.h
index 20417634020..571f4e74c60 100644
--- a/source/blender/editors/include/ED_screen.h
+++ b/source/blender/editors/include/ED_screen.h
@@ -57,15 +57,14 @@ struct wmMsgSubscribeKey;
 struct wmMsgSubscribeValue;
 struct wmNotifier;
 struct wmOperatorType;
+struct wmRegionListenerParams;
+struct wmRegionMessageSubscribeParams;
+struct wmSpaceTypeListenerParams;
 struct wmWindow;
 struct wmWindowManager;
 
 /* regions */
-void ED_region_do_listen(struct wmWindow *win,
-                         struct ScrArea *area,
-                         struct ARegion *region,
-                         struct wmNotifier *note,
-                         const Scene *scene);
+void ED_region_do_listen(struct wmRegionListenerParams *params);
 void ED_region_do_layout(struct bContext *C, struct ARegion *region);
 void ED_region_do_draw(struct bContext *C, struct ARegion *region);
 void ED_region_exit(struct bContext *C, struct ARegion *region);
@@ -144,29 +143,11 @@ void ED_area_do_msg_notify_tag_refresh(struct bContext *C,
                                        struct wmMsgSubscribeKey *msg_key,
                                        struct wmMsgSubscribeValue *msg_val);
 
-void ED_area_do_mgs_subscribe_for_tool_header(const struct bContext *C,
-                                              struct WorkSpace *workspace,
-                                              struct Scene *scene,
-                                              struct bScreen *screen,
-                                              struct ScrArea *area,
-                                              struct ARegion *region,
-                                              struct wmMsgBus *mbus);
-void ED_area_do_mgs_subscribe_for_tool_ui(const struct bContext *C,
-                                          struct WorkSpace *workspace,
-                                          struct Scene *scene,
-                                          struct bScreen *screen,
-                                          struct ScrArea *area,
-                                          struct ARegion *region,
-                                          struct wmMsgBus *mbus);
+void ED_area_do_mgs_subscribe_for_tool_header(struct wmRegionMessageSubscribeParams *params);
+void ED_area_do_mgs_subscribe_for_tool_ui(struct wmRegionMessageSubscribeParams *params);
 
 /* message bus */
-void ED_region_message_subscribe(struct bContext *C,
-                                 struct WorkSpace *workspace,
-                                 struct Scene *scene,
-                                 struct bScreen *screen,
-                                 struct ScrArea *area,
-                                 struct ARegion *region,
-                                 struct wmMsgBus *mbus);
+void ED_region_message_subscribe(struct wmRegionMessageSubscribeParams *params);
 
 /* spaces */
 void ED_spacetypes_keymap(struct wmKeyConfig *keyconf);
@@ -178,7 +159,7 @@ void ED_area_exit(struct bContext *C, struct ScrArea *area);
 int ED_screen_area_active(const struct bContext *C);
 void ED_screen_global_areas_refresh(struct wmWindow *win);
 void ED_screen_global_areas_sync(struct wmWindow *win);
-void ED_area_do_listen(struct wmWindow *win, ScrArea *area, struct wmNotifier *note, Scene *scene);
+void ED_area_do_listen(struct wmSpaceTypeListenerParams *params);
 void ED_area_tag_redraw(ScrArea *area);
 void ED_area_tag_redraw_no_rebuild(ScrArea *area);
 void ED_area_tag_redraw_regiontype(ScrArea *area, int type);
@@ -427,13 +408,8 @@ void ED_region_cache_draw_cached_segments(struct ARegion *region,
                                           const int efra);
 
 /* area_utils.c */
-void ED_region_generic_tools_region_message_subscribe(const struct bContext *C,
-                                                      struct WorkSpace *workspace,
-                                                      struct Scene *scene,
-                                                      struct bScreen *screen,
-                                                      struct ScrArea *area,
-                                                      struct ARegion *region,
-                                                      struct wmMsgBus *mbus);
+void ED_region_generic_tools_region_message_subscribe(
+    struct wmRegionMessageSubscribeParams *params);
 int ED_region_generic_tools_region_snap_size(const struct ARegion *region, int size, int axis);
 
 /* area_query.c */
diff --git a/source/blender/editors/interface/interface_region_popup.c b/source/blender/editors/interface/interface_region_popup.c
index 93e3dbb2cc8..c6c6cd1eeea 100644
--- a/source/blender/editors/interface/interface_region_popup.c
+++ b/source/blender/editors/interface/interface_region_popup.c
@@ -413,12 +413,11 @@ static void ui_block_region_draw(const bContext *C, ARegion *region)
 /**
  * Use to refresh centered popups on screen resizing (for splash).
  */
-static void ui_block_region_popup_window_listener(wmWindow *UNUSED(win),
-                                                  ScrArea *UNUSED(area),
-                                                  ARegion *region,
-                                                  wmNotifier *wmn,
-                                                  const Scene *UNUSED(scene))
+static void ui_block_region_popup_window_listener(wmRegionListenerParams *params)
 {
+  ARegion *region = params->region;
+  wmNotifier *wmn = params->notifier;
+
   switch (wmn->category) {
     case NC_WINDOW: {
       switch (wmn->action) {
diff --git a/source/blender/editors/screen/area.c b/source/blender/editors/screen/area.c
index 581169d823e..24773ccbbee 100644
--- a/source/blender/editors/screen/area.c
+++ b/source/blender/editors/screen/area.c
@@ -141,13 +141,15 @@ void ED_region_pixelspace(ARegion *region)
 }
 
 /* only exported for WM */
-void ED_region_do_listen(
-    wmWindow *win, ScrArea *area, ARegion *region, wmNotifier *note, const Scene *scene)
+void ED_region_do_listen(wmRegionListenerParams *params)
 {
+  ARegion *region = params->region;
+  wmNotifier *notifier = params->notifier;
+
   /* generic notes first */
-  switch (note->category) {
+  switch (notifier->category) {
     case NC_WM:
-      if (note->data == ND_FILEREAD) {
+      if (notifier->data == ND_FILEREAD) {
         ED_region_tag_redraw(region);
       }
       break;
@@ -157,16 +159,16 @@ void ED_region_do_listen(
   }
 
   if (region->type && region->type->listener) {
-    region->type->listener(win, area, region, note, scene);
+    region->type->listener(params);
   }
 }
 
 /* only exported for WM */
-void ED_area_do_listen(wmWindow *win, ScrArea *area, wmNotifier *note, Scene *scene)
+void ED_area_do_listen(wmSpaceTypeListenerParams *params)
 {
   /* no generic notes? */
-  if (area->type && area->type->listener) {
-    area->type->listener(win, area, note, scene);
+  if (params->area->type && params->area->type->listener) {
+    params->area->type->listener(params);
   }
 }
 
@@ -418,16 +420,13 @@ void ED_area_do_msg_notify_tag_refresh(
   ED_area_tag_refresh(area);
 }
 
-void ED_area_do_mgs_subscribe_for_tool_header(
-    /* Follow ARegionType.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)
+/* Follow ARegionType.message_subscribe */
+void ED_area_do_mgs_subscribe_for_tool_header(wmRegionMessageSubscribeParams *params)
 {
+  struct wmMsgBus *mbus = params->message_bus;
+  WorkSpace *workspace = params->workspace;
+  ARegion *region = params->region;
+
   BLI_assert(region->regiontype == RGN_TYPE_TOOL_HEADER);
   wmMsgSubscribeValue msg_sub_value_region_tag_redraw = {
       .owner = region,
@@ -438,16 +437,12 @@ void ED_area_do_mgs_subscribe_for_tool_header(
       mbus, &workspace->id, workspace, WorkSpace, tools, &msg_sub_value_region_tag_redraw);
 }
 
-void ED_area_do_mgs_subscribe_for_tool_ui(
-    /* Follow ARegionType.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)
+void ED_area_do_mgs_subscribe_for_tool_ui(wmRegionMessageSubscribeParams *params)
 {
+  struct wmMsgBus *mbus = params->message_bus;
+  WorkSpace *workspace = params->workspace;
+  ARegion *region = params->region;
+
   BLI_assert(region->regiontype == RGN_TYPE_UI);
   const char *panel_category_tool = "Tool";
   const char *category = UI_panel_category_active_get(region, false);
@@ -634,7 +629,16 @@ void ED_region_do_draw(bContext *C, ARegion *region)
       WM_msg_subscribe_rna(mbus, &ptr, NULL, &msg_sub_value_region_tag_redraw, __func__);
     }
 
-    ED_region_message_subscribe(C, workspace, scene, screen, area, region, mbus);
+    wmRegionMessageSubscribeParams message_subscribe_params = {
+        .context = C,
+        .message_bus = mbus,
+        .workspace = workspace,
+        .scene = scene,
+        .screen = screen,
+        .area = area,
+        .region = region,
+    };
+    ED_region_message_subscribe(&message_subscribe_params);
   }
 }
 
@@ -4027,14 +4031,12 @@ void ED_region_cache_draw_cached_segments(
 /**
  * Generate subscriptions for this region.
  */
-void ED_region_message_subscribe(bContext *C,
-                                 struct WorkSpace *workspace,
-                                 struct Scene *scene,
-                                 struct bScreen *screen,
-                                 struct ScrArea *area,
-                                 struct ARegion *region,
-                                 struct wmMsgBus *mbus)
+void ED_region_message_subscribe(wmRegionMessageSubscribeParams *params)
 {
+  ARegion *region = params->region;
+  const bContext *C = params->context;
+  struct wmMsgBus *mbus = params->message_bus;
+
   if (region->gizmo_map != NULL) {
     WM_gizmomap_message_subscribe(C, region->gizmo_map, region, mbus);
   }
@@ -4044,7 +4046,7 @@ void ED_region_message_subscribe(bContext *C,
   }
 
   if (region->type->message_subscribe != NULL) {
-    region->type->message_subscribe(C, workspace, scene, screen, area, region, mbus);
+    region->type->message_subscribe(params);
   }
 }
 
diff --git a/source/blender/editors/screen/area_utils.c b/source/blender/editors/screen/area_utils.c
index 075759f1120..e362563260b 100644
--- a/source/blender/editors/screen/area_utils.c
+++ b/source/blender/editors/screen/area_utils.c
@@ -22,6 +22,8 @@
 
 #include "DNA_userdef_types.h"
 
+#include "BKE_screen.h"
+
 #include "BLI_blenlib.h"
 #include "BLI_utildefines.h"
 
@@ -42,14 +44,11 @@
 /**
  * Callback for #ARegionType.message_subscribe
  */
-void ED_region_generic_tools_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)
+void ED_region_generic_tools_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,
diff --git a/source/blender/editors/space_action/space_action.c b/source/blender/editors/space_action/space_action.c
index ff0201f9702..9cb7ec69df1 100644
--- a/source/blender/editors/space_action/space_action.c
+++ b/source/blender/editors/space_action/space_action.c
@@ -305,12 +305,11 @@ static void action_header_region_draw(const bContext *C, ARegion *region)
   ED_region_header(C, region);
 }
 
-static void action_channel_region_listener(wmWindow *UNUSED(win),
-                                           ScrArea *UNUSED(area),
-                                           ARegion *region,
-                                           wmNotifier *wmn,
-                                           const Scene *UNUSED(scene))
+static void action_channel_region_listener(wmRegionListenerParams *params)
 {
+  ARegion *region = params->region;
+  wmNotifier *wmn = params->notifier;
+
   /* context changes */
   switch (wmn->category) {
     case NC_ANIMATION:
@@ -356,14 +355,13 @@ static void action_channel_region_listener(wmWindow *UNUSED(win),
   }
 }
 
-static void saction_channel_region_message_subscribe(const struct bContext *UNUSED(C),
-                                                     struct WorkSpace *UNUSED(workspace),
-                                                     struct Scene *UNUSED(scene),
-                                                     struct bScreen *screen,
-                                                     struct ScrArea *area,
-                                                     struct ARegion *region,
-                                                     struct wmMsgBus *mbus)
+static void saction_channel_region_message_subscribe(wmRegionMessageSubscribeParams *params)
 {
+  struct wmMsgBus *mbus = params->message_bus;
+  bScreen *screen = params->screen;
+  ScrArea *area = params->area;
+  ARegion *region = params->region;
+
   PointerRNA ptr;
   RNA_pointer_create(&screen->id, &RNA_SpaceDopeSheetEditor, area->spacedata.first, &ptr);
 
@@ -401,12 +399,11 @@ static void saction_channel_region_message_subscribe(const struct bContext *UNUS
   }
 }
 
-static void action_main_region_listener(wmWindow *UNUSED(win),
-                                        ScrArea *UNUSED(area),
-                                        ARegion *region,
-                                        wmNotifier *wmn,
-                                        const Scene *UNUSED(scene))
+static void action_main_region_listener(wmRegionListenerParams *params)
 {
+  ARegion *region = params->region;
+  wmNotifier *wmn = params->notifier;
+
   /* context changes */
   switch (wmn->category) {
     case NC_ANIMATION:
@@ -460,14 +457,14 @@ static void action_main_region_listener(wmWindow *UNUSED(win),
   }
 }
 
-static void saction_main_region_message_subscribe(const struct bContext *C,
-                                                  struct WorkSpace *workspace,
-                                                  struct Scene *scene,
-                                                  struct bScreen *screen,
-                                                  struct ScrArea *area,
-                                                  struct ARegion *region,
-                                                  struct wmMsgBus *mbus)
+static void saction_main_region_message_subscribe(wmRegionMessageSubscribeParams *params)
 {
+  struct wmMsgBus *mbus = params->message_bus;
+  Scene *scene = params->scene;
+  bScreen *screen = params->screen;
+  ScrArea *area = params->area;
+  ARegion *region = params->region;
+
   PointerRNA ptr;
   RNA_pointer_create(&screen->id, &RNA_SpaceDopeSheetEditor, area->spacedata.first, &ptr);
 
@@ -502,15 +499,14 @@ static void saction_main_region_message_subscribe(const struct bContext *C,
   }
 
   /* Now run the general "channels region" one - since channels and main should be in sync */
-  saction_channel_region_message_subscribe(C, workspace, scene, screen, area, region, mbus);
+  saction_channel_region_message_subscribe(params);
 }
 
 /* editor level listener */
-static void action_listener(wmWindow *UNUSED(win),
-                            ScrArea *area,
-                            wmNotifier *wmn,
-                            Scene *UNUSED(scene))
+static void action_listener(wmSpaceTypeListenerParams *params)
 {
+  ScrArea *area = params->area;
+  wmNotifier *wmn = params->notifier;
   SpaceAction *saction = (SpaceAction *)area->spacedata.first;
 
   /* context changes */
@@ -660,12 +656,11 @@ static void action_listener(wmWindow *UNUSED(win),
   }
 }
 
-static void action_header_region_listener(wmWindow *UNUSED(win),
-                                          ScrArea *area,
-                                          ARegion *region,
-                                          wmNotifier *wmn,
-                                          const Scene *UNUSED(scene))
+static void action_header_region_listener(wmRegionListenerParams *params)
 {
+  ScrArea *area = params->area;
+  ARegion *region = params->region;
+  wmNotifier *wmn = params->notifier;
   SpaceAction *saction = (SpaceAction *)area->spacedata.first;
 
   /* context changes */
@@ -737,12 +732,11 @@ static void action_buttons_area_draw(const bContext *C, ARegion *region)
   ED_region_panels(C, region);
 }
 
-static void action_region_listener(wmWindow *UNUSED(win),
-                                   ScrArea *UNUSED(area),
-                                   ARegion *region,
-                                   wmNotifier *wmn,
-                                   const Scene *UNUSED(scene))
+static void action_region_listener(wmRegionListenerParams *params)
 {
+  ARegion *region = params->region;
+  wmNotifier *wmn = params->notifier;
+
   /* context changes */
   switch (wmn->category) {
     case NC_ANIMATION:
diff --git a/source/blender/editors/space_buttons/space_buttons.c b/source/blender/editors/space_buttons/space_buttons.c
index e50ca2ec92b..797bb00dec2 100644
--- a/source/blender/editors/space_buttons/space_buttons.c
+++ b/source/blender/editors/space_buttons/space_buttons.c
@@ -514,12 +514,11 @@ static void buttons_main_region_layout(const bContext *C, ARegion *region)
   sbuts->mainbo = sbuts->mainb;
 }
 
-static void buttons_main_region_listener(wmWindow *UNUSED(win),
-                                         ScrArea *UNUSED(area),
-                                         ARegion *region,
-                                         wmNotifier *wmn,
-                                         const Scene *UNUSED(scene))
+static void buttons_main_region_listener(wmRegionListenerParams *params)
 {
+  ARegion *region = params->region;
+  wmNotifier *wmn = params->notifier;
+
   /* context changes */
   switch (wmn->category) {
     case NC_SCREEN:
@@ -567,15 +566,13 @@ static void buttons_header_region_draw(const bContext *C, ARegion *region)
   ED_region_header(C, region);
 }
 
-static void buttons_header_region_message_subscribe(const bContext *UNUSED(C),
-                                                    WorkSpace *UNUSED(workspace),
-                                                    Scene *UNUSED(scene),
-                                                    bScreen *UNUSED(screen),
-                                                    ScrArea *area,
-                                                    ARegion *region,
-                                                    struct wmMsgBus *mbus)
+static void buttons_header_region_message_subscribe(wmRegionMessageSubscribeParams *params)
 {
+  struct wmMsgBus *mbus = params->message_bus;
+  ScrArea *area = params->area;
+  ARegion *region = params->region;
   SpaceProperties *sbuts = area->spacedata.first;
+
   wmMsgSubscribeValue msg_sub_value_region_tag_redraw = {
       .owner = region,
       .user_data = region,
@@ -621,14 +618,11 @@ static void buttons_navigation_bar_region_draw(const bContext *C, ARegion *regio
   ED_region_panels_draw(C, region);
 }
 
-static void buttons_navigation_bar_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 buttons_navigation_bar_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,
@@ -657,11 +651,10 @@ static void buttons_area_redraw(ScrArea *area, short buttons)
  * \{ */
 
 /* reused! */
-static void buttons_area_listener(wmWindow *UNUSED(win),
-                                  ScrArea *area,
-                                  wmNotifier *wmn,
-                                  Scene *UNUSED(scene))
+static void buttons_area_listener(wmSpaceTypeListenerParams *params)
 {
+  ScrArea *area = params->area;
+  wmNotifier *wmn = params->notifier;
   SpaceProperties *sbuts = area->spacedata.first;
 
   /* context changes */
diff --git a/source/blender/editors/space_clip/space_clip.c b/source/blender/editors/space_clip/space_clip.c
index 085dbccabb2..3806c1494e3 100644
--- a/source/blender/editors/space_clip/space_clip.c
+++ b/source/blender/editors/space_clip/space_clip.c
@@ -229,7 +229,7 @@ static void clip_scopes_check_gpencil_change(ScrArea *area)
   }
 }
 
-static void clip_area_sync_frame_from_scene(ScrArea *area, Scene *scene)
+static void clip_area_sync_frame_from_scene(ScrArea *area, const Scene *scene)
 {
   SpaceClip *space_clip = (SpaceClip *)area->spacedata.first;
   BKE_movieclip_user_set_frame(&space_clip->user, scene->r.cfra);
@@ -334,8 +334,12 @@ static SpaceLink *clip_duplicate(SpaceLink *sl)
   return (SpaceLink *)scn;
 }
 
-static void clip_listener(wmWindow *UNUSED(win), ScrArea *area, wmNotifier *wmn, Scene *scene)
+static void clip_listener(wmSpaceTypeListenerParams *params)
 {
+  ScrArea *area = params->area;
+  wmNotifier *wmn = params->notifier;
+  const Scene *scene = params->scene;
+
   /* context changes */
   switch (wmn->category) {
     case NC_SCENE:
@@ -1004,12 +1008,11 @@ static void clip_main_region_draw(const bContext *C, ARegion *region)
   WM_gizmomap_draw(region->gizmo_map, C, WM_GIZMOMAP_DRAWSTEP_2D);
 }
 
-static void clip_main_region_listener(wmWindow *UNUSED(win),
-                                      ScrArea *UNUSED(area),
-                                      ARegion *region,
-                                      wmNotifier *wmn,
-                                      const Scene *UNUSED(scene))
+static void clip_main_region_listener(wmRegionListenerParams *params)
 {
+  ARegion *region = params->region;
+  wmNotifier *wmn = params->notifier;
+
   /* context changes */
   switch (wmn->category) {
     case NC_GPENCIL:
@@ -1140,11 +1143,7 @@ static void clip_preview_region_draw(const bContext *C, ARegion *region)
   }
 }
 
-static void clip_preview_region_listener(wmWindow *UNUSED(win),
-                                         ScrArea *UNUSED(area),
-                                         ARegion *UNUSED(region),
-                                         wmNotifier *UNUSED(wmn),
-                                         const Scene *UNUSED(scene))
+static void clip_preview_region_listener(wmRegionListenerParams *UNUSED(params))
 {
 }
 
@@ -1185,11 +1184,7 @@ static void clip_channels_region_draw(const bContext *C, ARegion *region)
   UI_view2d_view_restore(C);
 }
 
-static void clip_channels_region_listener(wmWindow *UNUSED(win),
-                                          ScrArea *UNUSED(area),
-                                          ARegion *UNUSED(region),
-                                          wmNotifier *UNUSED(wmn),
-                                          const Scene *UNUSED(scene))
+static void clip_channels_region_listener(wmRegionListenerParams *UNUSED(params))
 {
 }
 
@@ -1206,12 +1201,11 @@ static void clip_header_region_draw(const bContext *C, ARegion *region)
   ED_region_header(C, region);
 }
 
-static void clip_header_region_listener(wmWindow *UNUSED(win),
-                                        ScrArea *UNUSED(area),
-                                        ARegion *region,
-                                        wmNotifier *wmn,
-                                        const Scene *UNUSED(scene))
+static void clip_header_region_listener(wmRegionListenerParams *params)
 {
+  ARegion *region = params->region;
+  wmNotifier *wmn = params->notifier;
+
   /* context changes */
   switch (wmn->category) {
     case NC_SCENE:
@@ -1249,12 +1243,11 @@ static void clip_tools_region_draw(const bContext *C, ARegion *region)
 
 /****************** tool properties region ******************/
 
-static void clip_props_region_listener(wmWindow *UNUSED(win),
-                                       ScrArea *UNUSED(area),
-                                       ARegion *region,
-                                       wmNotifier *wmn,
-                                       const Scene *UNUSED(scene))
+static void clip_props_region_listener(wmRegionListenerParams *params)
 {
+  ARegion *region = params->region;
+  wmNotifier *wmn = params->notifier;
+
   /* context changes */
   switch (wmn->category) {
     case NC_WM:
@@ -1302,12 +1295,11 @@ static void clip_properties_region_draw(const bContext *C, ARegion *region)
   ED_region_panels(C, region);
 }
 
-static void clip_properties_region_listener(wmWindow *UNUSED(win),
-                                            ScrArea *UNUSED(area),
-                                            ARegion *region,
-                                            wmNotifier *wmn,
-                                            const Scene *UNUSED(scene))
+static void clip_properties_region_listener(wmRegionListenerParams *params)
 {
+  ARegion *region = params->region;
+  wmNotifier *wmn = params->notifier;
+
   /* context changes */
   switch (wmn->category) {
     case NC_GPENCIL:
diff --git a/source/blender/editors/space_console/space_console.c b/source/blender/editors/space_console/space_console.c
index 9b8e9e0e871..ba95a3cabb6 100644
--- a/source/blender/editors/space_console/space_console.c
+++ b/source/blender/editors/space_console/space_console.c
@@ -273,13 +273,11 @@ static void console_header_region_draw(const bContext *C, ARegion *region)
   ED_region_header(C, region);
 }
 
-static void console_main_region_listener(wmWindow *UNUSED(win),
-                                         ScrArea *area,
-                                         ARegion *region,
-                                         wmNotifier *wmn,
-                                         const Scene *UNUSED(scene))
+static void console_main_region_listener(wmRegionListenerParams *params)
 {
-  // SpaceInfo *sinfo = area->spacedata.first;
+  ScrArea *area = params->area;
+  ARegion *region = params->region;
+  wmNotifier *wmn = params->notifier;
 
   /* context changes */
   switch (wmn->category) {
diff --git a/source/blender/editors/space_file/space_file.c b/source/blender/editors/space_file/space_file.c
index 9fb69c7301a..273532c6b84 100644
--- a/source/blender/editors/space_file/space_file.c
+++ b/source/blender/editors/space_file/space_file.c
@@ -392,11 +392,10 @@ static void file_refresh(const bContext *C, ScrArea *area)
   ED_area_tag_redraw(area);
 }
 
-static void file_listener(wmWindow *UNUSED(win),
-                          ScrArea *area,
-                          wmNotifier *wmn,
-                          Scene *UNUSED(scene))
+static void file_listener(wmSpaceTypeListenerParams *params)
 {
+  ScrArea *area = params->area;
+  wmNotifier *wmn = params->notifier;
   SpaceFile *sfile = (SpaceFile *)area->spacedata.first;
 
   /* context changes */
@@ -447,12 +446,11 @@ static void file_main_region_init(wmWindowManager *wm, ARegion *region)
   WM_event_add_keymap_handler_v2d_mask(&region->handlers, keymap);
 }
 
-static void file_main_region_listener(wmWindow *UNUSED(win),
-                                      ScrArea *UNUSED(area),
-                                      ARegion *region,
-                                      wmNotifier *wmn,
-                                      const Scene *UNUSED(scene))
+static void file_main_region_listener(wmRegionListenerParams *params)
 {
+  ARegion *region = params->region;
+  wmNotifier *wmn = params->notifier;
+
   /* context changes */
   switch (wmn->category) {
     case NC_SPACE:
@@ -468,16 +466,15 @@ static void file_main_region_listener(wmWindow *UNUSED(win),
   }
 }
 
-static void file_main_region_message_subscribe(const struct bContext *UNUSED(C),
-                                               struct WorkSpace *UNUSED(workspace),
-                                               struct Scene *UNUSED(scene),
-                                               struct bScreen *screen,
-                                               struct ScrArea *area,
-                                               struct ARegion *region,
-                                               struct wmMsgBus *mbus)
+static void file_main_region_message_subscribe(wmRegionMessageSubscribeParams *params)
 {
+  struct wmMsgBus *mbus = params->message_bus;
+  bScreen *screen = params->screen;
+  ScrArea *area = params->area;
+  ARegion *region = params->region;
   SpaceFile *sfile = area->spacedata.first;
-  FileSelectParams *params = ED_fileselect_ensure_active_params(sfile);
+
+  FileSelectParams *file_params = ED_fileselect_ensure_active_params(sfile);
   /* This is a bit odd that a region owns the subscriber for an area,
    * keep for now since all subscribers for WM are regions.
    * May be worth re-visiting later. */
@@ -499,7 +496,7 @@ static void file_main_region_message_subscribe(const struct bContext *UNUSED(C),
   /* FileSelectParams */
   {
     PointerRNA ptr;
-    RNA_pointer_create(&screen->id, &RNA_FileSelectParams, params, &ptr);
+    RNA_pointer_create(&screen->id, &RNA_FileSelectParams, file_params, &ptr);
 
     /* All properties for this space type. */
     WM_msg_subscribe_rna(mbus, &ptr, NULL, &msg_sub_value_area_tag_refresh, __func__);
@@ -649,18 +646,8 @@ static void file_tools_region_draw(const bContext *C, ARegion *region)
   ED_region_panels(C, region);
 }
 
-static void file_tools_region_listener(wmWindow *UNUSED(win),
-                                       ScrArea *UNUSED(area),
-                                       ARegion *UNUSED(region),
-                                       wmNotifier *UNUSED(wmn),
-                                       const Scene *UNUSED(scene))
+static void file_tools_region_listener(wmRegionListenerParams *UNUSED(params))
 {
-#if 0
-  /* context changes */
-  switch (wmn->category) {
-    /* pass */
-  }
-#endif
 }
 
 /* add handlers, stuff you only do once or on area/region changes */
@@ -717,12 +704,11 @@ static void file_execution_region_draw(const bContext *C, ARegion *region)
   ED_region_panels(C, region);
 }
 
-static void file_ui_region_listener(wmWindow *UNUSED(win),
-                                    ScrArea *UNUSED(area),
-                                    ARegion *region,
-                                    wmNotifier *wmn,
-                                    const Scene *UNUSED(scene))
+static void file_ui_region_listener(wmRegionListenerParams *params)
 {
+  ARegion *region = params->region;
+  wmNotifier *wmn = params->notifier;
+
   /* context changes */
   switch (wmn->category) {
     case NC_SPACE:
diff --git a/source/blender/editors/space_graph/space_graph.c b/source/blender/editors/space_graph/space_graph.c
index 791039498e8..2fab393b1b3 100644
--- a/source/blender/editors/space_graph/space_graph.c
+++ b/source/blender/editors/space_graph/space_graph.c
@@ -403,12 +403,11 @@ static void graph_buttons_region_draw(const bContext *C, ARegion *region)
   ED_region_panels(C, region);
 }
 
-static void graph_region_listener(wmWindow *UNUSED(win),
-                                  ScrArea *UNUSED(area),
-                                  ARegion *region,
-                                  wmNotifier *wmn,
-                                  const Scene *UNUSED(scene))
+static void graph_region_listener(wmRegionListenerParams *params)
 {
+  ARegion *region = params->region;
+  wmNotifier *wmn = params->notifier;
+
   /* context changes */
   switch (wmn->category) {
     case NC_ANIMATION:
@@ -470,14 +469,14 @@ static void graph_region_listener(wmWindow *UNUSED(win),
   }
 }
 
-static void graph_region_message_subscribe(const struct bContext *UNUSED(C),
-                                           struct WorkSpace *UNUSED(workspace),
-                                           struct Scene *scene,
-                                           struct bScreen *screen,
-                                           struct ScrArea *area,
-                                           struct ARegion *region,
-                                           struct wmMsgBus *mbus)
+static void graph_region_message_subscribe(wmRegionMessageSubscribeParams *params)
 {
+  struct wmMsgBus *mbus = params->message_bus;
+  Scene *scene = params->scene;
+  bScreen *screen = params->screen;
+  ScrArea *area = params->area;
+  ARegion *region = params->region;
+
   PointerRNA ptr;
   RNA_pointer_create(&screen->id, &RNA_SpaceGraphEditor, area->spacedata.first, &ptr);
 
@@ -546,11 +545,10 @@ static void graph_region_message_subscribe(const struct bContext *UNUSED(C),
 }
 
 /* editor level listener */
-static void graph_listener(wmWindow *UNUSED(win),
-                           ScrArea *area,
-                           wmNotifier *wmn,
-                           Scene *UNUSED(scene))
+static void graph_listener(wmSpaceTypeListenerParams *params)
 {
+  ScrArea *area = params->area;
+  wmNotifier *wmn = params->notifier;
   SpaceGraph *sipo = (SpaceGraph *)area->spacedata.first;
 
   /* context changes */
diff --git a/source/blender/editors/space_image/space_image.c b/source/blender/editors/space_image/space_image.c
index 1981f04682d..8411507dfa7 100644
--- a/source/blender/editors/space_image/space_image.c
+++ b/source/blender/editors/space_image/space_image.c
@@ -320,8 +320,11 @@ static void image_refresh(const bContext *C, ScrArea *area)
   }
 }
 
-static void image_listener(wmWindow *win, ScrArea *area, wmNotifier *wmn, Scene *UNUSED(scene))
+static void image_listener(wmSpaceTypeListenerParams *params)
 {
+  wmWindow *win = params->window;
+  ScrArea *area = params->area;
+  wmNotifier *wmn = params->notifier;
   SpaceImage *sima = (SpaceImage *)area->spacedata.first;
 
   /* context changes */
@@ -723,12 +726,12 @@ static void image_main_region_draw(const bContext *C, ARegion *region)
   draw_image_cache(C, region);
 }
 
-static void image_main_region_listener(wmWindow *UNUSED(win),
-                                       ScrArea *area,
-                                       ARegion *region,
-                                       wmNotifier *wmn,
-                                       const Scene *UNUSED(scene))
+static void image_main_region_listener(wmRegionListenerParams *params)
 {
+  ScrArea *area = params->area;
+  ARegion *region = params->region;
+  wmNotifier *wmn = params->notifier;
+
   /* context changes */
   switch (wmn->category) {
     case NC_GEOM:
@@ -838,12 +841,11 @@ static void image_buttons_region_draw(const bContext *C, ARegion *region)
   ED_region_panels_draw(C, region);
 }
 
-static void image_buttons_region_listener(wmWindow *UNUSED(win),
-                                          ScrArea *UNUSED(area),
-                                          ARegion *region,
-                                          wmNotifier *wmn,
-                                          const Scene *UNUSED(scene))
+static void image_buttons_region_listener(wmRegionListenerParams *params)
 {
+  ARegion *region = params->region;
+  wmNotifier *wmn = params->notifier;
+
   /* context changes */
   switch (wmn->category) {
     case NC_TEXTURE:
@@ -901,12 +903,11 @@ static void image_tools_region_draw(const bContext *C, ARegion *region)
   ED_region_panels(C, region);
 }
 
-static void image_tools_region_listener(wmWindow *UNUSED(win),
-                                        ScrArea *UNUSED(area),
-                                        ARegion *region,
-                                        wmNotifier *wmn,
-                                        const Scene *UNUSED(scene))
+static void image_tools_region_listener(wmRegionListenerParams *params)
 {
+  ARegion *region = params->region;
+  wmNotifier *wmn = params->notifier;
+
   /* context changes */
   switch (wmn->category) {
     case NC_GPENCIL:
@@ -958,12 +959,11 @@ static void image_header_region_draw(const bContext *C, ARegion *region)
   ED_region_header(C, region);
 }
 
-static void image_header_region_listener(wmWindow *UNUSED(win),
-                                         ScrArea *UNUSED(area),
-                                         ARegion *region,
-                                         wmNotifier *wmn,
-                                         const Scene *UNUSED(scene))
+static void image_header_region_listener(wmRegionListenerParams *params)
 {
+  ARegion *region = params->region;
+  wmNotifier *wmn = params->notifier;
+
   /* context changes */
   switch (wmn->category) {
     case NC_SCENE:
diff --git a/source/blender/editors/space_info/space_info.c b/source/blender/editors/space_info/space_info.c
index 8d3f21aefeb..6339bab2dcf 100644
--- a/source/blender/editors/space_info/space_info.c
+++ b/source/blender/editors/space_info/space_info.c
@@ -204,13 +204,10 @@ static void info_header_region_draw(const bContext *C, ARegion *region)
   ED_region_header(C, region);
 }
 
-static void info_main_region_listener(wmWindow *UNUSED(win),
-                                      ScrArea *UNUSED(area),
-                                      ARegion *region,
-                                      wmNotifier *wmn,
-                                      const Scene *UNUSED(scene))
+static void info_main_region_listener(wmRegionListenerParams *params)
 {
-  // SpaceInfo *sinfo = area->spacedata.first;
+  ARegion *region = params->region;
+  wmNotifier *wmn = params->notifier;
 
   /* context changes */
   switch (wmn->category) {
@@ -223,12 +220,11 @@ static void info_main_region_listener(wmWindow *UNUSED(win),
   }
 }
 
-static void info_header_listener(wmWindow *UNUSED(win),
-                                 ScrArea *UNUSED(area),
-                                 ARegion *region,
-                                 wmNotifier *wmn,
-                                 const Scene *UNUSED(scene))
+static void info_header_listener(wmRegionListenerParams *params)
 {
+  ARegion *region = params->region;
+  wmNotifier *wmn = params->notifier;
+
   /* context changes */
   switch (wmn->category) {
     case NC_SCREEN:
@@ -259,14 +255,11 @@ static void info_header_listener(wmWindow *UNUSED(win),
   }
 }
 
-static void info_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 info_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,
diff --git a/source/blender/editors/space_nla/space_nla.c b/source/blender/editors/space_nla/space_nla.c
index c6fe1b8539e..0d6ef279327 100644
--- a/source/blender/editors/space_nla/space_nla.c
+++ b/source/blender/editors/space_nla/space_nla.c
@@ -324,12 +324,11 @@ static void nla_buttons_region_draw(const bContext *C, ARegion *region)
   ED_region_panels(C, region);
 }
 
-static void nla_region_listener(wmWindow *UNUSED(win),
-                                ScrArea *UNUSED(area),
-                                ARegion *region,
-                                wmNotifier *wmn,
-                                const Scene *UNUSED(scene))
+static void nla_region_listener(wmRegionListenerParams *params)
 {
+  ARegion *region = params->region;
+  wmNotifier *wmn = params->notifier;
+
   /* context changes */
   switch (wmn->category) {
     case NC_ANIMATION:
@@ -364,12 +363,11 @@ static void nla_region_listener(wmWindow *UNUSED(win),
   }
 }
 
-static void nla_main_region_listener(wmWindow *UNUSED(win),
-                                     ScrArea *UNUSED(area),
-                                     ARegion *region,
-                                     wmNotifier *wmn,
-                                     const Scene *UNUSED(scene))
+static void nla_main_region_listener(wmRegionListenerParams *params)
 {
+  ARegion *region = params->region;
+  wmNotifier *wmn = params->notifier;
+
   /* context changes */
   switch (wmn->category) {
     case NC_ANIMATION:
@@ -423,14 +421,14 @@ static void nla_main_region_listener(wmWindow *UNUSED(win),
   }
 }
 
-static void nla_main_region_message_subscribe(const struct bContext *UNUSED(C),
-                                              struct WorkSpace *UNUSED(workspace),
-                                              struct Scene *scene,
-                                              struct bScreen *screen,
-                                              struct ScrArea *area,
-                                              struct ARegion *region,
-                                              struct wmMsgBus *mbus)
+static void nla_main_region_message_subscribe(wmRegionMessageSubscribeParams *params)
 {
+  struct wmMsgBus *mbus = params->message_bus;
+  Scene *scene = params->scene;
+  bScreen *screen = params->screen;
+  ScrArea *area = params->area;
+  ARegion *region = params->region;
+
   PointerRNA ptr;
   RNA_pointer_create(&screen->id, &RNA_SpaceNLA, area->spacedata.first, &ptr);
 
@@ -465,12 +463,11 @@ static void nla_main_region_message_subscribe(const struct bContext *UNUSED(C),
   }
 }
 
-static void nla_channel_region_listener(wmWindow *UNUSED(win),
-                                        ScrArea *UNUSED(area),
-                                        ARegion *region,
-                                        wmNotifier *wmn,
-                                        const Scene *UNUSED(scene))
+static void nla_channel_region_listener(wmRegionListenerParams *params)
 {
+  ARegion *region = params->region;
+  wmNotifier *wmn = params->notifier;
+
   /* context changes */
   switch (wmn->category) {
     case NC_ANIMATION:
@@ -508,14 +505,13 @@ static void nla_channel_region_listener(wmWindow *UNUSED(win),
   }
 }
 
-static void nla_channel_region_message_subscribe(const struct bContext *UNUSED(C),
-                                                 struct WorkSpace *UNUSED(workspace),
-                                                 struct Scene *UNUSED(scene),
-                                                 struct bScreen *screen,
-                                                 struct ScrArea *area,
-                                                 struct ARegion *region,
-                                                 struct wmMsgBus *mbus)
+static void nla_channel_region_message_subscribe(wmRegionMessageSubscribeParams *params)
 {
+  struct wmMsgBus *mbus = params->message_bus;
+  bScreen *screen = params->screen;
+  ScrArea *area = params->area;
+  ARegion *region = params->region;
+
   PointerRNA ptr;
   RNA_pointer_create(&screen->id, &RNA_SpaceNLA, area->spacedata.first, &ptr);
 
@@ -543,11 +539,11 @@ static void nla_channel_region_message_subscribe(const struct bContext *UNUSED(C
 }
 
 /* editor level listener */
-static void nla_listener(wmWindow *UNUSED(win),
-                         ScrArea *area,
-                         wmNotifier *wmn,
-                         Scene *UNUSED(scene))
+static void nla_listener(wmSpaceTypeListenerParams *params)
 {
+  ScrArea *area = params->area;
+  wmNotifier *wmn = params->notifier;
+
   /* context changes */
   switch (wmn->category) {
     case NC_ANIMATION:
diff --git a/source/blender/editors/space_node/space_node.c b/source/blender/editors/space_node/space_node.c
index ad7632377a3..ddd791b326f 100644
--- a/source/blender/editors/space_node/space_node.c
+++ b/source/blender/editors/space_node/space_node.c
@@ -328,11 +328,11 @@ static void node_init(struct wmWindowManager *UNUSED(wm), ScrArea *UNUSED(area))
 {
 }
 
-static void node_area_listener(wmWindow *UNUSED(win),
-                               ScrArea *area,
-                               wmNotifier *wmn,
-                               Scene *UNUSED(scene))
+static void node_area_listener(wmSpaceTypeListenerParams *params)
 {
+  ScrArea *area = params->area;
+  wmNotifier *wmn = params->notifier;
+
   /* note, ED_area_tag_refresh will re-execute compositor */
   SpaceNode *snode = area->spacedata.first;
   /* shaderfrom is only used for new shading nodes, otherwise all shaders are from objects */
@@ -703,12 +703,10 @@ static void node_header_region_draw(const bContext *C, ARegion *region)
 }
 
 /* used for header + main region */
-static void node_region_listener(wmWindow *UNUSED(win),
-                                 ScrArea *UNUSED(area),
-                                 ARegion *region,
-                                 wmNotifier *wmn,
-                                 const Scene *UNUSED(scene))
+static void node_region_listener(wmRegionListenerParams *params)
 {
+  ARegion *region = params->region;
+  wmNotifier *wmn = params->notifier;
   wmGizmoMap *gzmap = region->gizmo_map;
 
   /* context changes */
diff --git a/source/blender/editors/space_outliner/space_outliner.c b/source/blender/editors/space_outliner/space_outliner.c
index 6c9d4433abd..4cfd72e9544 100644
--- a/source/blender/editors/space_outliner/space_outliner.c
+++ b/source/blender/editors/space_outliner/space_outliner.c
@@ -102,12 +102,11 @@ static void outliner_main_region_free(ARegion *UNUSED(region))
 {
 }
 
-static void outliner_main_region_listener(wmWindow *UNUSED(win),
-                                          ScrArea *area,
-                                          ARegion *region,
-                                          wmNotifier *wmn,
-                                          const Scene *UNUSED(scene))
+static void outliner_main_region_listener(wmRegionListenerParams *params)
 {
+  ScrArea *area = params->area;
+  ARegion *region = params->region;
+  wmNotifier *wmn = params->notifier;
   SpaceOutliner *space_outliner = area->spacedata.first;
 
   /* context changes */
@@ -264,15 +263,13 @@ static void outliner_main_region_listener(wmWindow *UNUSED(win),
   }
 }
 
-static void outliner_main_region_message_subscribe(const struct bContext *UNUSED(C),
-                                                   struct WorkSpace *UNUSED(workspace),
-                                                   struct Scene *UNUSED(scene),
-                                                   struct bScreen *UNUSED(screen),
-                                                   struct ScrArea *area,
-                                                   struct ARegion *region,
-                                                   struct wmMsgBus *mbus)
+static void outliner_main_region_message_subscribe(wmRegionMessageSubscribeParams *params)
 {
+  struct wmMsgBus *mbus = params->message_bus;
+  ScrArea *area = params->area;
+  ARegion *region = params->region;
   SpaceOutliner *space_outliner = area->spacedata.first;
+
   wmMsgSubscribeValue msg_sub_value_region_tag_redraw = {
       .owner = region,
       .user_data = region,
@@ -301,12 +298,11 @@ static void outliner_header_region_free(ARegion *UNUSED(region))
 {
 }
 
-static void outliner_header_region_listener(wmWindow *UNUSED(win),
-                                            ScrArea *UNUSED(area),
-                                            ARegion *region,
-                                            wmNotifier *wmn,
-                                            const Scene *UNUSED(scene))
+static void outliner_header_region_listener(wmRegionListenerParams *params)
 {
+  ARegion *region = params->region;
+  wmNotifier *wmn = params->notifier;
+
   /* context changes */
   switch (wmn->category) {
     case NC_SCENE:
diff --git a/source/blender/editors/space_script/space_script.c b/source/blender/editors/space_script/space_script.c
index 3330ba14530..68697f20f9c 100644
--- a/source/blender/editors/space_script/space_script.c
+++ b/source/blender/editors/space_script/space_script.c
@@ -156,13 +156,8 @@ static void script_header_region_draw(const bContext *C, ARegion *region)
   ED_region_header(C, region);
 }
 
-static void script_main_region_listener(wmWindow *UNUSED(win),
-                                        ScrArea *UNUSED(area),
-                                        ARegion *UNUSED(region),
-                                        wmNotifier *UNUSED(wmn),
-                                        const Scene *UNUSED(scene))
+static void script_main_region_listener(wmRegionListenerParams *UNUSED(params))
 {
-/* context changes */
 /* XXX - Todo, need the ScriptSpace accessible to get the python script to run. */
 #if 0
   BPY_run_script_space_listener()
diff --git a/source/blender/editors/space_sequencer/space_sequencer.c b/source/blender/editors/space_sequencer/space_sequencer.c
index b11e2a32b87..a7c4a2a849b 100644
--- a/source/blender/editors/space_sequencer/space_sequencer.c
+++ b/source/blender/editors/space_sequencer/space_sequencer.c
@@ -334,11 +334,11 @@ static SpaceLink *sequencer_duplicate(SpaceLink *sl)
   return (SpaceLink *)sseqn;
 }
 
-static void sequencer_listener(wmWindow *UNUSED(win),
-                               ScrArea *area,
-                               wmNotifier *wmn,
-                               Scene *UNUSED(scene))
+static void sequencer_listener(wmSpaceTypeListenerParams *params)
 {
+  ScrArea *area = params->area;
+  wmNotifier *wmn = params->notifier;
+
   /* Context changes. */
   switch (wmn->category) {
     case NC_SCENE:
@@ -534,12 +534,11 @@ static void sequencer_main_region_draw_overlay(const bContext *C, ARegion *regio
   draw_timeline_seq_display(C, region);
 }
 
-static void sequencer_main_region_listener(wmWindow *UNUSED(win),
-                                           ScrArea *UNUSED(area),
-                                           ARegion *region,
-                                           wmNotifier *wmn,
-                                           const Scene *UNUSED(scene))
+static void sequencer_main_region_listener(wmRegionListenerParams *params)
 {
+  ARegion *region = params->region;
+  wmNotifier *wmn = params->notifier;
+
   /* Context changes. */
   switch (wmn->category) {
     case NC_SCENE:
@@ -579,14 +578,12 @@ static void sequencer_main_region_listener(wmWindow *UNUSED(win),
   }
 }
 
-static void sequencer_main_region_message_subscribe(const struct bContext *UNUSED(C),
-                                                    struct WorkSpace *UNUSED(workspace),
-                                                    struct Scene *scene,
-                                                    struct bScreen *UNUSED(screen),
-                                                    struct ScrArea *UNUSED(area),
-                                                    struct ARegion *region,
-                                                    struct wmMsgBus *mbus)
+static void sequencer_main_region_message_subscribe(wmRegionMessageSubscribeParams *params)
 {
+  struct wmMsgBus *mbus = params->message_bus;
+  Scene *scene = params->scene;
+  ARegion *region = params->region;
+
   wmMsgSubscribeValue msg_sub_value_region_tag_redraw = {
       .owner = region,
       .user_data = region,
@@ -746,12 +743,11 @@ static void sequencer_preview_region_draw(const bContext *C, ARegion *region)
   }
 }
 
-static void sequencer_preview_region_listener(wmWindow *UNUSED(win),
-                                              ScrArea *UNUSED(area),
-                                              ARegion *region,
-                                              wmNotifier *wmn,
-                                              const Scene *UNUSED(scene))
+static void sequencer_preview_region_listener(wmRegionListenerParams *params)
 {
+  ARegion *region = params->region;
+  wmNotifier *wmn = params->notifier;
+
   /* Context changes. */
   switch (wmn->category) {
     case NC_GPENCIL:
@@ -816,12 +812,11 @@ static void sequencer_buttons_region_draw(const bContext *C, ARegion *region)
   ED_region_panels(C, region);
 }
 
-static void sequencer_buttons_region_listener(wmWindow *UNUSED(win),
-                                              ScrArea *UNUSED(area),
-                                              ARegion *region,
-                                              wmNotifier *wmn,
-                                              const Scene *UNUSED(scene))
+static void sequencer_buttons_region_listener(wmRegionListenerParams *params)
 {
+  ARegion *region = params->region;
+  wmNotifier *wmn = params->notifier;
+
   /* Context changes. */
   switch (wmn->category) {
     case NC_GPENCIL:
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,
diff --git a/source/blender/editors/space_text/space_text.c b/source/blender/editors/space_text/space_text.c
index 0f5ac5abe1d..90b75d26526 100644
--- a/source/blender/editors/space_text/space_text.c
+++ b/source/blender/editors/space_text/space_text.c
@@ -122,11 +122,10 @@ static SpaceLink *text_duplicate(SpaceLink *sl)
   return (SpaceLink *)stextn;
 }
 
-static void text_listener(wmWindow *UNUSED(win),
-                          ScrArea *area,
-                          wmNotifier *wmn,
-                          Scene *UNUSED(scene))
+static void text_listener(wmSpaceTypeListenerParams *params)
 {
+  ScrArea *area = params->area;
+  wmNotifier *wmn = params->notifier;
   SpaceText *st = area->spacedata.first;
 
   /* context changes */
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,
diff --git a/source/blender/editors/space_userpref/space_userpref.c b/source/blender/editors/space_userpref/space_userpref.c
index 3efdee9cec9..52c97ed5014 100644
--- a/source/blender/editors/space_userpref/space_userpref.c
+++ b/source/blender/editors/space_userpref/space_userpref.c
@@ -183,46 +183,20 @@ static void userpref_execute_region_init(wmWindowManager *wm, ARegion *region)
   region->v2d.keepzoom |= V2D_LOCKZOOM_X | V2D_LOCKZOOM_Y;
 }
 
-static void userpref_main_region_listener(wmWindow *UNUSED(win),
-                                          ScrArea *UNUSED(area),
-                                          ARegion *UNUSED(region),
-                                          wmNotifier *UNUSED(wmn),
-                                          const Scene *UNUSED(scene))
+static void userpref_main_region_listener(wmRegionListenerParams *UNUSED(params))
 {
-  /* context changes */
 }
 
-static void userpref_header_listener(wmWindow *UNUSED(win),
-                                     ScrArea *UNUSED(area),
-                                     ARegion *UNUSED(region),
-                                     wmNotifier *UNUSED(wmn),
-                                     const Scene *UNUSED(scene))
+static void userpref_header_listener(wmRegionListenerParams *UNUSED(params))
 {
-  /* context changes */
-#if 0
-  switch (wmn->category) {
-    default:
-      break;
-  }
-#endif
 }
 
-static void userpref_navigation_region_listener(wmWindow *UNUSED(win),
-                                                ScrArea *UNUSED(area),
-                                                ARegion *UNUSED(region),
-                                                wmNotifier *UNUSED(wmn),
-                                                const Scene *UNUSED(scene))
+static void userpref_navigation_region_listener(wmRegionListenerParams *UNUSED(params))
 {
-  /* context changes */
 }
 
-static void userpref_execute_region_listener(wmWindow *UNUSED(win),
-                                             ScrArea *UNUSED(area),
-                                             ARegion *UNUSED(region),
-                                             wmNotifier *UNUSED(wmn),
-                                             const Scene *UNUSED(scene))
+static void userpref_execute_region_listener(wmRegionListenerParams *UNUSED(params))
 {
-  /* context changes */
 }
 
 /* only called once, from space/spacetypes.c */
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 */
diff --git a/source/blender/windowmanager/gizmo/WM_gizmo_api.h b/source/blender/windowmanager/gizmo/WM_gizmo_api.h
index 70ddae4d724..cf1a7628267 100644
--- a/source/blender/windowmanager/gizmo/WM_gizmo_api.h
+++ b/source/blender/windowmanager/gizmo/WM_gizmo_api.h
@@ -301,7 +301,7 @@ void WM_gizmomap_draw(struct wmGizmoMap *gzmap,
 void WM_gizmomap_add_handlers(struct ARegion *region, struct wmGizmoMap *gzmap);
 bool WM_gizmomap_select_all(struct bContext *C, struct wmGizmoMap *gzmap, const int action);
 bool WM_gizmomap_cursor_set(const struct wmGizmoMap *gzmap, struct wmWindow *win);
-void WM_gizmomap_message_subscribe(struct bContext *C,
+void WM_gizmomap_message_subscribe(const struct bContext *C,
                                    struct wmGizmoMap *gzmap,
                                    struct ARegion *region,
                                    struct wmMsgBus *mbus);
diff --git a/source/blender/windowmanager/gizmo/intern/wm_gizmo_map.c b/source/blender/windowmanager/gizmo/intern/wm_gizmo_map.c
index 479768c3536..12c6eb46c12 100644
--- a/source/blender/windowmanager/gizmo/intern/wm_gizmo_map.c
+++ b/source/blender/windowmanager/gizmo/intern/wm_gizmo_map.c
@@ -1156,7 +1156,7 @@ ListBase *wm_gizmomap_groups_get(wmGizmoMap *gzmap)
   return &gzmap->groups;
 }
 
-void WM_gizmomap_message_subscribe(bContext *C,
+void WM_gizmomap_message_subscribe(const bContext *C,
                                    wmGizmoMap *gzmap,
                                    ARegion *region,
                                    struct wmMsgBus *mbus)
diff --git a/source/blender/windowmanager/intern/wm_event_system.c b/source/blender/windowmanager/intern/wm_event_system.c
index 859336d0338..d08051dd5fb 100644
--- a/source/blender/windowmanager/intern/wm_event_system.c
+++ b/source/blender/windowmanager/intern/wm_event_system.c
@@ -543,13 +543,31 @@ void wm_event_do_notifiers(bContext *C)
         ED_screen_do_listen(C, note);
 
         LISTBASE_FOREACH (ARegion *, region, &screen->regionbase) {
-          ED_region_do_listen(win, NULL, region, note, scene);
+          wmRegionListenerParams region_params = {
+              .area = NULL,
+              .region = region,
+              .scene = scene,
+              .notifier = note,
+          };
+          ED_region_do_listen(&region_params);
         }
 
         ED_screen_areas_iter (win, screen, area) {
-          ED_area_do_listen(win, area, note, scene);
+          wmSpaceTypeListenerParams area_params = {
+              .window = win,
+              .area = area,
+              .notifier = note,
+              .scene = scene,
+          };
+          ED_area_do_listen(&area_params);
           LISTBASE_FOREACH (ARegion *, region, &area->regionbase) {
-            ED_region_do_listen(win, area, region, note, scene);
+            wmRegionListenerParams region_params = {
+                .area = area,
+                .region = region,
+                .scene = scene,
+                .notifier = note,
+            };
+            ED_region_do_listen(&region_params);
           }
         }
       }