Cleanup: Simplify bContextStore API with C++ concepts

Remove the need for `CTX_store_copy` and `CTX_store_free` by using
C++ copy constructors, unique pointers, and `std::optional`. A few types
are made non-trivial to support this.

source/blender/blenkernel/BKE_context.h

@@ -159,8 +159,6 @@ void CTX_store_set(bContext *C, bContextStore *store);
 const PointerRNA *CTX_store_ptr_lookup(const bContextStore *store,
                                        blender::StringRefNull name,
                                        const StructRNA *type = nullptr);
-bContextStore *CTX_store_copy(const bContextStore *store);
-void CTX_store_free(bContextStore *store);
 
 #endif
 

source/blender/blenkernel/intern/context.cc

@@ -191,16 +191,6 @@ const PointerRNA *CTX_store_ptr_lookup(const bContextStore *store,
   return nullptr;
 }
 
-bContextStore *CTX_store_copy(const bContextStore *store)
-{
-  return MEM_new<bContextStore>(__func__, *store);
-}
-
-void CTX_store_free(bContextStore *store)
-{
-  MEM_delete(store);
-}
-
 /* is python initialized? */
 
 bool CTX_py_init_get(bContext *C)

source/blender/editors/interface/interface_handlers.cc

@@ -503,7 +503,7 @@ struct uiAfterFunc {
   uiBlockInteraction_CallbackData custom_interaction_callbacks;
   uiBlockInteraction_Handle *custom_interaction_handle;
 
-  bContextStore *context;
+  std::optional<bContextStore> context;
 
   char undostr[BKE_UNDO_STR_MAX];
   char drawstr[UI_MAX_DRAW_STR];
@@ -789,7 +789,7 @@ static void ui_handle_afterfunc_add_operator_ex(wmOperatorType *ot,
   }
 
   if (context_but && context_but->context) {
-    after->context = CTX_store_copy(context_but->context);
+    after->context = *context_but->context;
   }
 
   if (context_but) {
@@ -905,7 +905,7 @@ static void ui_apply_but_func(bContext *C, uiBut *but)
   }
 
   if (but->context) {
-    after->context = CTX_store_copy(but->context);
+    after->context = *but->context;
   }
 
   ui_but_drawstr_without_sep_char(but, after->drawstr, sizeof(after->drawstr));
@@ -1020,7 +1020,7 @@ static void ui_apply_but_funcs_after(bContext *C)
     MEM_delete(afterf);
 
     if (after.context) {
-      CTX_store_set(C, after.context);
+      CTX_store_set(C, &after.context.value());
     }
 
     if (after.popup_op) {
@@ -1053,7 +1053,6 @@ static void ui_apply_but_funcs_after(bContext *C)
 
     if (after.context) {
       CTX_store_set(C, nullptr);
-      CTX_store_free(after.context);
     }
 
     if (after.func) {

source/blender/windowmanager/WM_types.hh

@@ -104,6 +104,7 @@ struct wmEvent;
 struct wmOperator;
 struct wmWindowManager;
 
+#include <memory>
 #include <string>
 
 #include "BLI_compiler_attrs.h"
@@ -1169,7 +1170,7 @@ struct wmDragActiveDropState {
    * If `active_dropbox` is set, additional context provided by the active (i.e. hovered) button.
    * Activated before context sensitive operations (polling, drawing, dropping).
    */
-  bContextStore *ui_context;
+  std::unique_ptr<bContextStore> ui_context;
 
   /**
    * Text to show when a dropbox poll succeeds (so the dropbox itself is available) but the

source/blender/windowmanager/intern/wm_dragdrop.cc

@@ -169,7 +169,7 @@ static void wm_dropbox_invoke(bContext *C, wmDrag *drag)
     }
     LISTBASE_FOREACH (wmDropBox *, drop, &dm->dropboxes) {
       if (drag->drop_state.ui_context) {
-        CTX_store_set(C, drag->drop_state.ui_context);
+        CTX_store_set(C, drag->drop_state.ui_context.get());
       }
 
       if (drop->on_drag_start) {
@@ -183,7 +183,7 @@ static void wm_dropbox_invoke(bContext *C, wmDrag *drag)
 wmDrag *WM_drag_data_create(
     bContext *C, int icon, eWM_DragDataType type, void *poin, double value, uint flags)
 {
-  wmDrag *drag = MEM_cnew<wmDrag>(__func__);
+  wmDrag *drag = MEM_new<wmDrag>(__func__);
 
   /* Keep track of future multi-touch drag too, add a mouse-pointer id or so. */
   /* if multiple drags are added, they're drawn as list */
@@ -264,7 +264,7 @@ void wm_drags_exit(wmWindowManager *wm, wmWindow *win)
   }
 }
 
-static bContextStore *wm_drop_ui_context_create(const bContext *C)
+static std::unique_ptr<bContextStore> wm_drop_ui_context_create(const bContext *C)
 {
   uiBut *active_but = UI_region_active_but_get(CTX_wm_region(C));
   if (!active_but) {
@@ -276,16 +276,7 @@ static bContextStore *wm_drop_ui_context_create(const bContext *C)
     return nullptr;
   }
 
-  return CTX_store_copy(but_context);
-}
-
-static void wm_drop_ui_context_free(bContextStore **context_store)
-{
-  if (!*context_store) {
-    return;
-  }
-  CTX_store_free(*context_store);
-  *context_store = nullptr;
+  return std::make_unique<bContextStore>(*but_context);
 }
 
 void WM_event_drag_image(wmDrag *drag, const ImBuf *imb, float scale)
@@ -327,7 +318,7 @@ void WM_drag_free(wmDrag *drag)
   if (drag->flags & WM_DRAG_FREE_DATA) {
     WM_drag_data_free(drag->type, drag->poin);
   }
-  wm_drop_ui_context_free(&drag->drop_state.ui_context);
+  drag->drop_state.ui_context.reset();
   if (drag->drop_state.free_disabled_info) {
     MEM_SAFE_FREE(drag->drop_state.disabled_info);
   }
@@ -338,7 +329,7 @@ void WM_drag_free(wmDrag *drag)
     }
     BLI_freelinkN(&drag->asset_items, asset_item);
   }
-  MEM_freeN(drag);
+  MEM_delete(drag);
 }
 
 void WM_drag_free_list(ListBase *lb)
@@ -378,7 +369,7 @@ static wmDropBox *dropbox_active(bContext *C,
       if (handler->dropboxes) {
         LISTBASE_FOREACH (wmDropBox *, drop, handler->dropboxes) {
           if (drag->drop_state.ui_context) {
-            CTX_store_set(C, drag->drop_state.ui_context);
+            CTX_store_set(C, drag->drop_state.ui_context.get());
           }
 
           if (!drop->poll(C, drag, event)) {
@@ -450,7 +441,7 @@ static void wm_drop_update_active(bContext *C, wmDrag *drag, const wmEvent *even
   }
 
   /* Update UI context, before polling so polls can query this context. */
-  wm_drop_ui_context_free(&drag->drop_state.ui_context);
+  drag->drop_state.ui_context.reset();
   drag->drop_state.ui_context = wm_drop_ui_context_create(C);
 
   wmDropBox *drop_prev = drag->drop_state.active_dropbox;
@@ -469,7 +460,7 @@ static void wm_drop_update_active(bContext *C, wmDrag *drag, const wmEvent *even
   }
 
   if (!drag->drop_state.active_dropbox) {
-    wm_drop_ui_context_free(&drag->drop_state.ui_context);
+    drag->drop_state.ui_context.reset();
   }
 }
 
@@ -478,7 +469,7 @@ void wm_drop_prepare(bContext *C, wmDrag *drag, wmDropBox *drop)
   const wmOperatorCallContext opcontext = wm_drop_operator_context_get(drop);
 
   if (drag->drop_state.ui_context) {
-    CTX_store_set(C, drag->drop_state.ui_context);
+    CTX_store_set(C, drag->drop_state.ui_context.get());
   }
 
   /* Optionally copy drag information to operator properties. Don't call it if the
@@ -1039,7 +1030,7 @@ void wm_drags_draw(bContext *C, wmWindow *win)
     if (drag->drop_state.active_dropbox) {
       CTX_wm_area_set(C, drag->drop_state.area_from);
       CTX_wm_region_set(C, drag->drop_state.region_from);
-      CTX_store_set(C, drag->drop_state.ui_context);
+      CTX_store_set(C, drag->drop_state.ui_context.get());
 
       if (region && drag->drop_state.active_dropbox->draw_in_view) {
         wmViewport(&region->winrct);

source/blender/windowmanager/intern/wm_event_system.cc

@@ -1862,7 +1862,7 @@ int WM_operator_call_py(bContext *C,
 struct uiOperatorWaitForInput {
   ScrArea *area;
   wmOperatorCallParams optype_params;
-  bContextStore *context;
+  std::optional<bContextStore> context;
 };
 
 static void ui_handler_wait_for_input_remove(bContext *C, void *userdata)
@@ -1874,9 +1874,6 @@ static void ui_handler_wait_for_input_remove(bContext *C, void *userdata)
     }
     MEM_freeN(opwait->optype_params.opptr);
   }
-  if (opwait->context) {
-    CTX_store_free(opwait->context);
-  }
 
   if (opwait->area != nullptr) {
     ED_area_status_text(opwait->area, nullptr);
@@ -1885,7 +1882,7 @@ static void ui_handler_wait_for_input_remove(bContext *C, void *userdata)
     ED_workspace_status_text(C, nullptr);
   }
 
-  MEM_freeN(opwait);
+  MEM_delete(opwait);
 }
 
 static int ui_handler_wait_for_input(bContext *C, const wmEvent *event, void *userdata)
@@ -1929,7 +1926,7 @@ static int ui_handler_wait_for_input(bContext *C, const wmEvent *event, void *us
     WM_cursor_modal_restore(win);
 
     if (state == EXECUTE) {
-      CTX_store_set(C, opwait->context);
+      CTX_store_set(C, opwait->context ? &opwait->context.value() : nullptr);
       WM_operator_name_call_ptr(C,
                                 opwait->optype_params.optype,
                                 opwait->optype_params.opcontext,
@@ -1995,7 +1992,7 @@ void WM_operator_name_call_ptr_with_depends_on_cursor(bContext *C,
 
   WM_cursor_modal_set(win, ot->cursor_pending);
 
-  uiOperatorWaitForInput *opwait = MEM_cnew<uiOperatorWaitForInput>(__func__);
+  uiOperatorWaitForInput *opwait = MEM_new<uiOperatorWaitForInput>(__func__);
   opwait->optype_params.optype = ot;
   opwait->optype_params.opcontext = opcontext;
   opwait->optype_params.opptr = properties;
@@ -2011,9 +2008,8 @@ void WM_operator_name_call_ptr_with_depends_on_cursor(bContext *C,
     }
   }
 
-  bContextStore *store = CTX_store_get(C);
-  if (store) {
-    opwait->context = CTX_store_copy(store);
+  if (bContextStore *store = CTX_store_get(C)) {
+    opwait->context = *store;
   }
 
   WM_event_add_ui_handler(C,