ViewLayer: Lazy sync of scene data.

When a change happens which invalidates view layers the syncing will be postponed until the first usage.
This will improve importing or adding many objects in a single operation/script.

`BKE_view_layer_need_resync_tag` is used to tag the view layer to be out of sync. Before accessing
`BKE_view_layer_active_base_get`, `BKE_view_layer_active_object_get`, `BKE_view_layer_active_collection`
or `BKE_view_layer_object_bases` the caller should call `BKE_view_layer_synced_ensure`.

Having two functions ensures that partial syncing could be added as smaller patches in the future. Tagging a
view layer out of sync could be replaced with a partial sync. Eventually the number of full resyncs could be
reduced. After all tagging has been replaced with partial syncs the ensure_sync could be phased out.

This patch has been added to discuss the details and consequences of the current approach. For clarity
the call to BKE_view_layer_ensure_sync is placed close to the getters.
In the future this could be placed in more strategical places to reduce the number of calls or improve
performance. Finding those strategical places isn't that clear. When multiple operations are grouped
in a single script you might want to always check for resync.

Some areas found that can be improved. This list isn't complete.
These areas aren't addressed by this patch as these changes would be hard to detect to the reviewer.
The idea is to add changes to these areas as a separate patch. It might be that the initial commit would reduce
performance compared to master, but will be fixed by the additional patches.

**Object duplication**
During object duplication the syncing is temporarily disabled. With this patch this isn't useful as when disabled
the view_layer is accessed to locate bases. This can be improved by first locating the source bases, then duplicate
and sync and locate the new bases. Will be solved in a separate patch for clarity reasons ({D15886}).

**Object add**
`BKE_object_add` not only adds a new object, but also selects and activates the new base. This requires the
view_layer to be resynced. Some callers reverse the selection and activation (See `get_new_constraint_target`).
We should make the selection and activation optional. This would make it possible to add multiple objects
without having to resync per object.

**Postpone Activate Base**
Setting the basact is done in many locations. They follow a rule as after an action find the base and set
the basact. Finding the base could require a resync. The idea is to store in the view_layer the object which
base will be set in the basact during the next sync, reducing the times resyncing needs to happen.

Reviewed By: mont29

Maniphest Tasks: T73411

Differential Revision: https://developer.blender.org/D15885

1 files changed, 80 insertions, 27 deletions

diff --git a/source/blender/editors/screen/screen_context.c b/source/blender/editors/screen/screen_context.c
index b96a4a10408..ffd76e70eb8 100644
--- a/source/blender/editors/screen/screen_context.c
+++ b/source/blender/editors/screen/screen_context.c
@@ -129,9 +129,11 @@ static eContextResult screen_ctx_visible_objects(const bContext *C, bContextData
 {
   wmWindow *win = CTX_wm_window(C);
   View3D *v3d = CTX_wm_view3d(C); /* This may be NULL in a lot of cases. */
+  Scene *scene = WM_window_get_active_scene(win);
   ViewLayer *view_layer = WM_window_get_active_view_layer(win);
+  BKE_view_layer_synced_ensure(scene, view_layer);
 
-  LISTBASE_FOREACH (Base *, base, &view_layer->object_bases) {
+  LISTBASE_FOREACH (Base *, base, BKE_view_layer_object_bases_get(view_layer)) {
     if (BASE_VISIBLE(v3d, base)) {
       CTX_data_id_list_add(result, &base->object->id);
     }
@@ -143,9 +145,11 @@ static eContextResult screen_ctx_selectable_objects(const bContext *C, bContextD
 {
   wmWindow *win = CTX_wm_window(C);
   View3D *v3d = CTX_wm_view3d(C); /* This may be NULL in a lot of cases. */
+  Scene *scene = WM_window_get_active_scene(win);
   ViewLayer *view_layer = WM_window_get_active_view_layer(win);
+  BKE_view_layer_synced_ensure(scene, view_layer);
 
-  LISTBASE_FOREACH (Base *, base, &view_layer->object_bases) {
+  LISTBASE_FOREACH (Base *, base, BKE_view_layer_object_bases_get(view_layer)) {
     if (BASE_SELECTABLE(v3d, base)) {
       CTX_data_id_list_add(result, &base->object->id);
     }
@@ -157,9 +161,11 @@ static eContextResult screen_ctx_selected_objects(const bContext *C, bContextDat
 {
   wmWindow *win = CTX_wm_window(C);
   View3D *v3d = CTX_wm_view3d(C); /* This may be NULL in a lot of cases. */
+  Scene *scene = WM_window_get_active_scene(win);
   ViewLayer *view_layer = WM_window_get_active_view_layer(win);
+  BKE_view_layer_synced_ensure(scene, view_layer);
 
-  LISTBASE_FOREACH (Base *, base, &view_layer->object_bases) {
+  LISTBASE_FOREACH (Base *, base, BKE_view_layer_object_bases_get(view_layer)) {
     if (BASE_SELECTED(v3d, base)) {
       CTX_data_id_list_add(result, &base->object->id);
     }
@@ -172,9 +178,11 @@ static eContextResult screen_ctx_selected_editable_objects(const bContext *C,
 {
   wmWindow *win = CTX_wm_window(C);
   View3D *v3d = CTX_wm_view3d(C); /* This may be NULL in a lot of cases. */
+  Scene *scene = WM_window_get_active_scene(win);
   ViewLayer *view_layer = WM_window_get_active_view_layer(win);
+  BKE_view_layer_synced_ensure(scene, view_layer);
 
-  LISTBASE_FOREACH (Base *, base, &view_layer->object_bases) {
+  LISTBASE_FOREACH (Base *, base, BKE_view_layer_object_bases_get(view_layer)) {
     if (BASE_SELECTED_EDITABLE(v3d, base)) {
       CTX_data_id_list_add(result, &base->object->id);
     }
@@ -186,10 +194,12 @@ static eContextResult screen_ctx_editable_objects(const bContext *C, bContextDat
 {
   wmWindow *win = CTX_wm_window(C);
   View3D *v3d = CTX_wm_view3d(C); /* This may be NULL in a lot of cases. */
+  Scene *scene = WM_window_get_active_scene(win);
   ViewLayer *view_layer = WM_window_get_active_view_layer(win);
+  BKE_view_layer_synced_ensure(scene, view_layer);
 
   /* Visible + Editable, but not necessarily selected */
-  LISTBASE_FOREACH (Base *, base, &view_layer->object_bases) {
+  LISTBASE_FOREACH (Base *, base, BKE_view_layer_object_bases_get(view_layer)) {
     if (BASE_EDITABLE(v3d, base)) {
       CTX_data_id_list_add(result, &base->object->id);
     }
@@ -203,7 +213,8 @@ static eContextResult screen_ctx_objects_in_mode(const bContext *C, bContextData
   View3D *v3d = CTX_wm_view3d(C); /* This may be NULL in a lot of cases. */
   const Scene *scene = WM_window_get_active_scene(win);
   ViewLayer *view_layer = WM_window_get_active_view_layer(win);
-  Object *obact = view_layer->basact ? view_layer->basact->object : NULL;
+  BKE_view_layer_synced_ensure(scene, view_layer);
+  Object *obact = BKE_view_layer_active_object_get(view_layer);
 
   if (obact && (obact->mode != OB_MODE_OBJECT)) {
     FOREACH_OBJECT_IN_MODE_BEGIN (scene, view_layer, v3d, obact->type, obact->mode, ob_iter) {
@@ -221,7 +232,8 @@ static eContextResult screen_ctx_objects_in_mode_unique_data(const bContext *C,
   View3D *v3d = CTX_wm_view3d(C); /* This may be NULL in a lot of cases. */
   const Scene *scene = WM_window_get_active_scene(win);
   ViewLayer *view_layer = WM_window_get_active_view_layer(win);
-  Object *obact = view_layer->basact ? view_layer->basact->object : NULL;
+  BKE_view_layer_synced_ensure(scene, view_layer);
+  Object *obact = BKE_view_layer_active_object_get(view_layer);
 
   if (obact && (obact->mode != OB_MODE_OBJECT)) {
     FOREACH_OBJECT_IN_MODE_BEGIN (scene, view_layer, v3d, obact->type, obact->mode, ob_iter) {
@@ -246,6 +258,7 @@ static eContextResult screen_ctx_visible_or_editable_bones_(const bContext *C,
   wmWindow *win = CTX_wm_window(C);
   const Scene *scene = WM_window_get_active_scene(win);
   ViewLayer *view_layer = WM_window_get_active_view_layer(win);
+  BKE_view_layer_synced_ensure(scene, view_layer);
   Object *obedit = BKE_view_layer_edit_object_get(view_layer);
 
   bArmature *arm = (obedit && obedit->type == OB_ARMATURE) ? obedit->data : NULL;
@@ -318,6 +331,7 @@ static eContextResult screen_ctx_selected_bones_(const bContext *C,
   wmWindow *win = CTX_wm_window(C);
   const Scene *scene = WM_window_get_active_scene(win);
   ViewLayer *view_layer = WM_window_get_active_view_layer(win);
+  BKE_view_layer_synced_ensure(scene, view_layer);
   Object *obedit = BKE_view_layer_edit_object_get(view_layer);
   bArmature *arm = (obedit && obedit->type == OB_ARMATURE) ? obedit->data : NULL;
   EditBone *flipbone = NULL;
@@ -389,7 +403,8 @@ static eContextResult screen_ctx_visible_pose_bones(const bContext *C, bContextD
   View3D *v3d = CTX_wm_view3d(C); /* This may be NULL in a lot of cases. */
   const Scene *scene = WM_window_get_active_scene(win);
   ViewLayer *view_layer = WM_window_get_active_view_layer(win);
-  Object *obact = view_layer->basact ? view_layer->basact->object : NULL;
+  BKE_view_layer_synced_ensure(scene, view_layer);
+  Object *obact = BKE_view_layer_active_object_get(view_layer);
   Object *obpose = BKE_object_pose_armature_get(obact);
   if (obpose && obpose->pose && obpose->data) {
     if (obpose != obact) {
@@ -418,7 +433,7 @@ static eContextResult screen_ctx_selected_pose_bones(const bContext *C, bContext
   View3D *v3d = CTX_wm_view3d(C); /* This may be NULL in a lot of cases. */
   const Scene *scene = WM_window_get_active_scene(win);
   ViewLayer *view_layer = WM_window_get_active_view_layer(win);
-  Object *obact = view_layer->basact ? view_layer->basact->object : NULL;
+  Object *obact = BKE_view_layer_active_object_get(view_layer);
   Object *obpose = BKE_object_pose_armature_get(obact);
   if (obpose && obpose->pose && obpose->data) {
     if (obpose != obact) {
@@ -445,8 +460,10 @@ static eContextResult screen_ctx_selected_pose_bones_from_active_object(const bC
                                                                         bContextDataResult *result)
 {
   wmWindow *win = CTX_wm_window(C);
+  const Scene *scene = WM_window_get_active_scene(win);
   ViewLayer *view_layer = WM_window_get_active_view_layer(win);
-  Object *obact = view_layer->basact ? view_layer->basact->object : NULL;
+  BKE_view_layer_synced_ensure(scene, view_layer);
+  Object *obact = BKE_view_layer_active_object_get(view_layer);
   Object *obpose = BKE_object_pose_armature_get(obact);
   if (obpose && obpose->pose && obpose->data) {
     if (obpose != obact) {
@@ -469,8 +486,10 @@ static eContextResult screen_ctx_selected_pose_bones_from_active_object(const bC
 static eContextResult screen_ctx_active_bone(const bContext *C, bContextDataResult *result)
 {
   wmWindow *win = CTX_wm_window(C);
+  const Scene *scene = WM_window_get_active_scene(win);
   ViewLayer *view_layer = WM_window_get_active_view_layer(win);
-  Object *obact = view_layer->basact ? view_layer->basact->object : NULL;
+  BKE_view_layer_synced_ensure(scene, view_layer);
+  Object *obact = BKE_view_layer_active_object_get(view_layer);
   if (obact && obact->type == OB_ARMATURE) {
     bArmature *arm = obact->data;
     if (arm->edbo) {
@@ -491,8 +510,10 @@ static eContextResult screen_ctx_active_bone(const bContext *C, bContextDataResu
 static eContextResult screen_ctx_active_pose_bone(const bContext *C, bContextDataResult *result)
 {
   wmWindow *win = CTX_wm_window(C);
+  const Scene *scene = WM_window_get_active_scene(win);
   ViewLayer *view_layer = WM_window_get_active_view_layer(win);
-  Object *obact = view_layer->basact ? view_layer->basact->object : NULL;
+  BKE_view_layer_synced_ensure(scene, view_layer);
+  Object *obact = BKE_view_layer_active_object_get(view_layer);
   Object *obpose = BKE_object_pose_armature_get(obact);
 
   bPoseChannel *pchan = BKE_pose_channel_active_if_layer_visible(obpose);
@@ -505,8 +526,10 @@ static eContextResult screen_ctx_active_pose_bone(const bContext *C, bContextDat
 static eContextResult screen_ctx_active_object(const bContext *C, bContextDataResult *result)
 {
   wmWindow *win = CTX_wm_window(C);
+  const Scene *scene = WM_window_get_active_scene(win);
   ViewLayer *view_layer = WM_window_get_active_view_layer(win);
-  Object *obact = view_layer->basact ? view_layer->basact->object : NULL;
+  BKE_view_layer_synced_ensure(scene, view_layer);
+  Object *obact = BKE_view_layer_active_object_get(view_layer);
 
   if (obact) {
     CTX_data_id_pointer_set(result, &obact->id);
@@ -517,8 +540,10 @@ static eContextResult screen_ctx_active_object(const bContext *C, bContextDataRe
 static eContextResult screen_ctx_object(const bContext *C, bContextDataResult *result)
 {
   wmWindow *win = CTX_wm_window(C);
+  const Scene *scene = WM_window_get_active_scene(win);
   ViewLayer *view_layer = WM_window_get_active_view_layer(win);
-  Object *obact = view_layer->basact ? view_layer->basact->object : NULL;
+  BKE_view_layer_synced_ensure(scene, view_layer);
+  Object *obact = BKE_view_layer_active_object_get(view_layer);
 
   if (obact) {
     CTX_data_id_pointer_set(result, &obact->id);
@@ -529,7 +554,9 @@ static eContextResult screen_ctx_object(const bContext *C, bContextDataResult *r
 static eContextResult screen_ctx_edit_object(const bContext *C, bContextDataResult *result)
 {
   wmWindow *win = CTX_wm_window(C);
+  Scene *scene = WM_window_get_active_scene(win);
   ViewLayer *view_layer = WM_window_get_active_view_layer(win);
+  BKE_view_layer_synced_ensure(scene, view_layer);
   Object *obedit = BKE_view_layer_edit_object_get(view_layer);
   /* convenience for now, 1 object per scene in editmode */
   if (obedit) {
@@ -541,8 +568,10 @@ static eContextResult screen_ctx_edit_object(const bContext *C, bContextDataResu
 static eContextResult screen_ctx_sculpt_object(const bContext *C, bContextDataResult *result)
 {
   wmWindow *win = CTX_wm_window(C);
+  const Scene *scene = WM_window_get_active_scene(win);
   ViewLayer *view_layer = WM_window_get_active_view_layer(win);
-  Object *obact = view_layer->basact ? view_layer->basact->object : NULL;
+  BKE_view_layer_synced_ensure(scene, view_layer);
+  Object *obact = BKE_view_layer_active_object_get(view_layer);
 
   if (obact && (obact->mode & OB_MODE_SCULPT)) {
     CTX_data_id_pointer_set(result, &obact->id);
@@ -553,8 +582,10 @@ static eContextResult screen_ctx_sculpt_object(const bContext *C, bContextDataRe
 static eContextResult screen_ctx_vertex_paint_object(const bContext *C, bContextDataResult *result)
 {
   wmWindow *win = CTX_wm_window(C);
+  const Scene *scene = WM_window_get_active_scene(win);
   ViewLayer *view_layer = WM_window_get_active_view_layer(win);
-  Object *obact = view_layer->basact ? view_layer->basact->object : NULL;
+  BKE_view_layer_synced_ensure(scene, view_layer);
+  Object *obact = BKE_view_layer_active_object_get(view_layer);
   if (obact && (obact->mode & OB_MODE_VERTEX_PAINT)) {
     CTX_data_id_pointer_set(result, &obact->id);
   }
@@ -564,8 +595,10 @@ static eContextResult screen_ctx_vertex_paint_object(const bContext *C, bContext
 static eContextResult screen_ctx_weight_paint_object(const bContext *C, bContextDataResult *result)
 {
   wmWindow *win = CTX_wm_window(C);
+  const Scene *scene = WM_window_get_active_scene(win);
   ViewLayer *view_layer = WM_window_get_active_view_layer(win);
-  Object *obact = view_layer->basact ? view_layer->basact->object : NULL;
+  BKE_view_layer_synced_ensure(scene, view_layer);
+  Object *obact = BKE_view_layer_active_object_get(view_layer);
   if (obact && (obact->mode & OB_MODE_ALL_WEIGHT_PAINT)) {
     CTX_data_id_pointer_set(result, &obact->id);
   }
@@ -575,8 +608,10 @@ static eContextResult screen_ctx_weight_paint_object(const bContext *C, bContext
 static eContextResult screen_ctx_image_paint_object(const bContext *C, bContextDataResult *result)
 {
   wmWindow *win = CTX_wm_window(C);
+  const Scene *scene = WM_window_get_active_scene(win);
   ViewLayer *view_layer = WM_window_get_active_view_layer(win);
-  Object *obact = view_layer->basact ? view_layer->basact->object : NULL;
+  BKE_view_layer_synced_ensure(scene, view_layer);
+  Object *obact = BKE_view_layer_active_object_get(view_layer);
   if (obact && (obact->mode & OB_MODE_TEXTURE_PAINT)) {
     CTX_data_id_pointer_set(result, &obact->id);
   }
@@ -587,8 +622,10 @@ static eContextResult screen_ctx_particle_edit_object(const bContext *C,
                                                       bContextDataResult *result)
 {
   wmWindow *win = CTX_wm_window(C);
+  const Scene *scene = WM_window_get_active_scene(win);
   ViewLayer *view_layer = WM_window_get_active_view_layer(win);
-  Object *obact = view_layer->basact ? view_layer->basact->object : NULL;
+  BKE_view_layer_synced_ensure(scene, view_layer);
+  Object *obact = BKE_view_layer_active_object_get(view_layer);
   if (obact && (obact->mode & OB_MODE_PARTICLE_EDIT)) {
     CTX_data_id_pointer_set(result, &obact->id);
   }
@@ -598,8 +635,10 @@ static eContextResult screen_ctx_particle_edit_object(const bContext *C,
 static eContextResult screen_ctx_pose_object(const bContext *C, bContextDataResult *result)
 {
   wmWindow *win = CTX_wm_window(C);
+  const Scene *scene = WM_window_get_active_scene(win);
   ViewLayer *view_layer = WM_window_get_active_view_layer(win);
-  Object *obact = view_layer->basact ? view_layer->basact->object : NULL;
+  BKE_view_layer_synced_ensure(scene, view_layer);
+  Object *obact = BKE_view_layer_active_object_get(view_layer);
   Object *obpose = BKE_object_pose_armature_get(obact);
   if (obpose) {
     CTX_data_id_pointer_set(result, &obpose->id);
@@ -742,8 +781,10 @@ static eContextResult screen_ctx_gpencil_data(const bContext *C, bContextDataRes
 {
   wmWindow *win = CTX_wm_window(C);
   ScrArea *area = CTX_wm_area(C);
+  const Scene *scene = WM_window_get_active_scene(win);
   ViewLayer *view_layer = WM_window_get_active_view_layer(win);
-  Object *obact = view_layer->basact ? view_layer->basact->object : NULL;
+  BKE_view_layer_synced_ensure(scene, view_layer);
+  Object *obact = BKE_view_layer_active_object_get(view_layer);
   /* FIXME: for some reason, CTX_data_active_object(C) returns NULL when called from these
    * situations (as outlined above - see Campbell's #ifdefs).
    * That causes the get_active function to fail when called from context.
@@ -761,8 +802,10 @@ static eContextResult screen_ctx_gpencil_data_owner(const bContext *C, bContextD
 {
   wmWindow *win = CTX_wm_window(C);
   ScrArea *area = CTX_wm_area(C);
+  const Scene *scene = WM_window_get_active_scene(win);
   ViewLayer *view_layer = WM_window_get_active_view_layer(win);
-  Object *obact = view_layer->basact ? view_layer->basact->object : NULL;
+  BKE_view_layer_synced_ensure(scene, view_layer);
+  Object *obact = BKE_view_layer_active_object_get(view_layer);
 
   /* Pointer to which data/datablock owns the reference to the Grease Pencil data being used
    * (as gpencil_data). */
@@ -812,8 +855,10 @@ static eContextResult screen_ctx_active_gpencil_layer(const bContext *C,
 {
   wmWindow *win = CTX_wm_window(C);
   ScrArea *area = CTX_wm_area(C);
+  const Scene *scene = WM_window_get_active_scene(win);
   ViewLayer *view_layer = WM_window_get_active_view_layer(win);
-  Object *obact = view_layer->basact ? view_layer->basact->object : NULL;
+  BKE_view_layer_synced_ensure(scene, view_layer);
+  Object *obact = BKE_view_layer_active_object_get(view_layer);
   bGPdata *gpd = ED_gpencil_data_get_active_direct(area, obact);
 
   if (gpd) {
@@ -850,8 +895,10 @@ static eContextResult screen_ctx_active_gpencil_frame(const bContext *C,
 {
   wmWindow *win = CTX_wm_window(C);
   ScrArea *area = CTX_wm_area(C);
+  const Scene *scene = WM_window_get_active_scene(win);
   ViewLayer *view_layer = WM_window_get_active_view_layer(win);
-  Object *obact = view_layer->basact ? view_layer->basact->object : NULL;
+  BKE_view_layer_synced_ensure(scene, view_layer);
+  Object *obact = BKE_view_layer_active_object_get(view_layer);
   bGPdata *gpd = ED_gpencil_data_get_active_direct(area, obact);
 
   if (gpd) {
@@ -869,8 +916,10 @@ static eContextResult screen_ctx_visible_gpencil_layers(const bContext *C,
 {
   wmWindow *win = CTX_wm_window(C);
   ScrArea *area = CTX_wm_area(C);
+  const Scene *scene = WM_window_get_active_scene(win);
   ViewLayer *view_layer = WM_window_get_active_view_layer(win);
-  Object *obact = view_layer->basact ? view_layer->basact->object : NULL;
+  BKE_view_layer_synced_ensure(scene, view_layer);
+  Object *obact = BKE_view_layer_active_object_get(view_layer);
   bGPdata *gpd = ED_gpencil_data_get_active_direct(area, obact);
 
   if (gpd) {
@@ -889,8 +938,10 @@ static eContextResult screen_ctx_editable_gpencil_layers(const bContext *C,
 {
   wmWindow *win = CTX_wm_window(C);
   ScrArea *area = CTX_wm_area(C);
+  const Scene *scene = WM_window_get_active_scene(win);
   ViewLayer *view_layer = WM_window_get_active_view_layer(win);
-  Object *obact = view_layer->basact ? view_layer->basact->object : NULL;
+  BKE_view_layer_synced_ensure(scene, view_layer);
+  Object *obact = BKE_view_layer_active_object_get(view_layer);
   bGPdata *gpd = ED_gpencil_data_get_active_direct(area, obact);
 
   if (gpd) {
@@ -909,8 +960,10 @@ static eContextResult screen_ctx_editable_gpencil_strokes(const bContext *C,
 {
   wmWindow *win = CTX_wm_window(C);
   ScrArea *area = CTX_wm_area(C);
+  const Scene *scene = WM_window_get_active_scene(win);
   ViewLayer *view_layer = WM_window_get_active_view_layer(win);
-  Object *obact = view_layer->basact ? view_layer->basact->object : NULL;
+  BKE_view_layer_synced_ensure(scene, view_layer);
+  Object *obact = BKE_view_layer_active_object_get(view_layer);
 
   bGPdata *gpd = ED_gpencil_data_get_active_direct(area, obact);
   const bool is_multiedit = (bool)GPENCIL_MULTIEDIT_SESSIONS_ON(gpd);