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, 14 insertions, 16 deletions

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 */