UI: Port view item features to base class, merge view item button types

No user visible changes expected.

Merges the tree row and grid tile button types, which were mostly doing
the same things. The idea is that there is a button type for
highlighting, as well as supporting general view item features (e.g.
renaming, drag/drop, etc.). So instead there is a view item button type
now. Also ports view item features like renaming, custom context menus,
drag controllers and drop controllers to `ui::AbstractViewItem` (the new
base class for all view items).

This should be quite an improvement because:
- Merges code that was duplicated over view items.
- Mentioned features (renaming, drag & drop, ...) are much easier to
  implement in new view types now. Most of it comes "for free".
- Further features will immediately become availalbe to all views (e.g.
  selection).
- Simplifies APIs, there don't have to be functions for individual view
  item types anymore.
- View item classes are split and thus less overwhelming visually.
- View item buttons now share all code (drawing, handling, etc.)
- We're soon running out of available button types, this commit merges
  two into one.

I was hoping I could do this in multiple smaller commits, but things
were quite intertwined so that would've taken quite some effort.

1 files changed, 22 insertions, 66 deletions

diff --git a/source/blender/editors/interface/interface_handlers.c b/source/blender/editors/interface/interface_handlers.c
index 2496136883d..0a50522a141 100644
--- a/source/blender/editors/interface/interface_handlers.c
+++ b/source/blender/editors/interface/interface_handlers.c
@@ -1151,7 +1151,10 @@ static void ui_apply_but_ROW(bContext *C, uiBlock *block, uiBut *but, uiHandleBu
   data->applied = true;
 }
 
-static void ui_apply_but_TREEROW(bContext *C, uiBlock *block, uiBut *but, uiHandleButtonData *data)
+static void ui_apply_but_VIEW_ITEM(bContext *C,
+                                   uiBlock *block,
+                                   uiBut *but,
+                                   uiHandleButtonData *data)
 {
   if (data->apply_through_extra_icon) {
     /* Don't apply this, it would cause unintended tree-row toggling when clicking on extra icons.
@@ -2128,10 +2131,10 @@ static bool ui_but_drag_init(bContext *C,
         return false;
       }
     }
-    else if (but->type == UI_BTYPE_TREEROW) {
-      uiButTreeRow *tree_row_but = (uiButTreeRow *)but;
-      if (tree_row_but->tree_item) {
-        UI_tree_view_item_drag_start(C, tree_row_but->tree_item);
+    else if (but->type == UI_BTYPE_VIEW_ITEM) {
+      const uiButViewItem *view_item_but = (uiButViewItem *)but;
+      if (view_item_but->view_item) {
+        UI_view_item_drag_start(C, view_item_but->view_item);
       }
     }
     else {
@@ -2289,11 +2292,8 @@ static void ui_apply_but(
     case UI_BTYPE_ROW:
       ui_apply_but_ROW(C, block, but, data);
       break;
-    case UI_BTYPE_GRID_TILE:
-      ui_apply_but_ROW(C, block, but, data);
-      break;
-    case UI_BTYPE_TREEROW:
-      ui_apply_but_TREEROW(C, block, but, data);
+    case UI_BTYPE_VIEW_ITEM:
+      ui_apply_but_VIEW_ITEM(C, block, but, data);
       break;
     case UI_BTYPE_LISTROW:
       ui_apply_but_LISTROW(C, block, but, data);
@@ -4764,53 +4764,13 @@ static int ui_do_but_TOG(bContext *C, uiBut *but, uiHandleButtonData *data, cons
   return WM_UI_HANDLER_CONTINUE;
 }
 
-static int ui_do_but_TREEROW(bContext *C,
-                             uiBut *but,
-                             uiHandleButtonData *data,
-                             const wmEvent *event)
-{
-  uiButTreeRow *tree_row_but = (uiButTreeRow *)but;
-  BLI_assert(tree_row_but->but.type == UI_BTYPE_TREEROW);
-
-  if (data->state == BUTTON_STATE_HIGHLIGHT) {
-    if (event->type == LEFTMOUSE) {
-      switch (event->val) {
-        case KM_PRESS:
-          /* Extra icons have priority, don't mess with them. */
-          if (ui_but_extra_operator_icon_mouse_over_get(but, data->region, event)) {
-            return WM_UI_HANDLER_BREAK;
-          }
-          button_activate_state(C, but, BUTTON_STATE_WAIT_DRAG);
-          data->dragstartx = event->xy[0];
-          data->dragstarty = event->xy[1];
-          return WM_UI_HANDLER_CONTINUE;
-
-        case KM_CLICK:
-          button_activate_state(C, but, BUTTON_STATE_EXIT);
-          return WM_UI_HANDLER_BREAK;
-
-        case KM_DBL_CLICK:
-          data->cancel = true;
-          UI_tree_view_item_begin_rename(tree_row_but->tree_item);
-          ED_region_tag_redraw(CTX_wm_region(C));
-          return WM_UI_HANDLER_BREAK;
-      }
-    }
-  }
-  else if (data->state == BUTTON_STATE_WAIT_DRAG) {
-    /* Let "default" button handling take care of the drag logic. */
-    return ui_do_but_EXIT(C, but, data, event);
-  }
-
-  return WM_UI_HANDLER_CONTINUE;
-}
-
-static int ui_do_but_GRIDTILE(bContext *C,
-                              uiBut *but,
-                              uiHandleButtonData *data,
-                              const wmEvent *event)
+static int ui_do_but_VIEW_ITEM(bContext *C,
+                               uiBut *but,
+                               uiHandleButtonData *data,
+                               const wmEvent *event)
 {
-  BLI_assert(but->type == UI_BTYPE_GRID_TILE);
+  uiButViewItem *view_item_but = (uiButViewItem *)but;
+  BLI_assert(view_item_but->but.type == UI_BTYPE_VIEW_ITEM);
 
   if (data->state == BUTTON_STATE_HIGHLIGHT) {
     if (event->type == LEFTMOUSE) {
@@ -4831,8 +4791,7 @@ static int ui_do_but_GRIDTILE(bContext *C,
 
         case KM_DBL_CLICK:
           data->cancel = true;
-          // uiButGridTile *grid_tile_but = (uiButGridTile *)but;
-          // UI_tree_view_item_begin_rename(grid_tile_but->tree_item);
+          UI_view_item_begin_rename(view_item_but->view_item);
           ED_region_tag_redraw(CTX_wm_region(C));
           return WM_UI_HANDLER_BREAK;
       }
@@ -7980,7 +7939,7 @@ static int ui_do_button(bContext *C, uiBlock *block, uiBut *but, const wmEvent *
        * to spawn the context menu should also activate the item. This makes it clear which item
        * will be operated on.
        * Apply the button immediately, so context menu polls get the right active item. */
-      if (ELEM(but->type, UI_BTYPE_TREEROW)) {
+      if (ELEM(but->type, UI_BTYPE_VIEW_ITEM)) {
         ui_apply_but(C, but->block, but, but->active, true);
       }
 
@@ -8045,11 +8004,8 @@ static int ui_do_button(bContext *C, uiBlock *block, uiBut *but, const wmEvent *
     case UI_BTYPE_ROW:
       retval = ui_do_but_TOG(C, but, data, event);
       break;
-    case UI_BTYPE_GRID_TILE:
-      retval = ui_do_but_GRIDTILE(C, but, data, event);
-      break;
-    case UI_BTYPE_TREEROW:
-      retval = ui_do_but_TREEROW(C, but, data, event);
+    case UI_BTYPE_VIEW_ITEM:
+      retval = ui_do_but_VIEW_ITEM(C, but, data, event);
       break;
     case UI_BTYPE_SCROLL:
       retval = ui_do_but_SCROLL(C, block, but, data, event);
@@ -9725,7 +9681,7 @@ static int ui_handle_view_items_hover(const wmEvent *event, const ARegion *regio
     }
 
     LISTBASE_FOREACH (uiBut *, but, &block->buttons) {
-      if (ui_but_is_view_item(but)) {
+      if (but->type == UI_BTYPE_VIEW_ITEM) {
         but->flag &= ~UI_ACTIVE;
         has_view_item = true;
       }
@@ -9752,7 +9708,7 @@ static int ui_handle_view_item_event(bContext *C,
                                      ARegion *region,
                                      uiBut *view_but)
 {
-  BLI_assert(ui_but_is_view_item(view_but));
+  BLI_assert(view_but->type == UI_BTYPE_VIEW_ITEM);
   if (event->type == LEFTMOUSE) {
     /* Will free active button if there already is one. */
     ui_handle_button_activate(C, region, view_but, BUTTON_ACTIVATE_OVER);