Python handlers: Pass depsgraph to events where it makes sense

The goal is to make it possible to access evaluated datablocks at a
corresponding context. For example, be able to check evaluated state
if an object used for rendering.

Allows to write scripts in a safe manner for T63548 and T60094.

Reviewers: brecht

Differential Revision: https://developer.blender.org/D5726

3 files changed, 57 insertions, 8 deletions

diff --git a/source/blender/blenkernel/BKE_callbacks.h b/source/blender/blenkernel/BKE_callbacks.h
index 380ce30668d..e15cf7fed18 100644
--- a/source/blender/blenkernel/BKE_callbacks.h
+++ b/source/blender/blenkernel/BKE_callbacks.h
@@ -21,8 +21,10 @@
 #ifndef __BKE_CALLBACKS_H__
 #define __BKE_CALLBACKS_H__
 
+struct Depsgraph;
 struct ID;
 struct Main;
+struct PointerRNA;
 
 /**
  * Common suffix uses:
@@ -59,12 +61,21 @@ typedef enum {
 
 typedef struct bCallbackFuncStore {
   struct bCallbackFuncStore *next, *prev;
-  void (*func)(struct Main *, struct ID *, void *arg);
+  void (*func)(struct Main *, struct PointerRNA **, const int num_pointers, void *arg);
   void *arg;
   short alloc;
 } bCallbackFuncStore;
 
-void BKE_callback_exec(struct Main *bmain, struct ID *self, eCbEvent evt);
+void BKE_callback_exec(struct Main *bmain,
+                       struct PointerRNA **pointers,
+                       const int num_pointers,
+                       eCbEvent evt);
+void BKE_callback_exec_null(struct Main *bmain, eCbEvent evt);
+void BKE_callback_exec_id(struct Main *bmain, struct ID *id, eCbEvent evt);
+void BKE_callback_exec_id_depsgraph(struct Main *bmain,
+                                    struct ID *id,
+                                    struct Depsgraph *depsgraph,
+                                    eCbEvent evt);
 void BKE_callback_add(bCallbackFuncStore *funcstore, eCbEvent evt);
 
 void BKE_callback_global_init(void);
diff --git a/source/blender/blenkernel/intern/callbacks.c b/source/blender/blenkernel/intern/callbacks.c
index cbecba2efe1..367fed818af 100644
--- a/source/blender/blenkernel/intern/callbacks.c
+++ b/source/blender/blenkernel/intern/callbacks.c
@@ -25,18 +25,55 @@
 
 #include "MEM_guardedalloc.h"
 
+#include "RNA_types.h"
+#include "RNA_access.h"
+
 static ListBase callback_slots[BKE_CB_EVT_TOT] = {{NULL}};
 
-void BKE_callback_exec(struct Main *bmain, struct ID *self, eCbEvent evt)
+void BKE_callback_exec(struct Main *bmain,
+                       struct PointerRNA **pointers,
+                       const int num_pointers,
+                       eCbEvent evt)
 {
   ListBase *lb = &callback_slots[evt];
   bCallbackFuncStore *funcstore;
 
   for (funcstore = lb->first; funcstore; funcstore = funcstore->next) {
-    funcstore->func(bmain, self, funcstore->arg);
+    funcstore->func(bmain, pointers, num_pointers, funcstore->arg);
   }
 }
 
+void BKE_callback_exec_null(struct Main *bmain, eCbEvent evt)
+{
+  BKE_callback_exec(bmain, NULL, 0, evt);
+}
+
+void BKE_callback_exec_id(struct Main *bmain, struct ID *id, eCbEvent evt)
+{
+  PointerRNA id_ptr;
+  RNA_id_pointer_create(id, &id_ptr);
+
+  PointerRNA *pointers[1] = {&id_ptr};
+
+  BKE_callback_exec(bmain, pointers, 1, evt);
+}
+
+void BKE_callback_exec_id_depsgraph(struct Main *bmain,
+                                    struct ID *id,
+                                    struct Depsgraph *depsgraph,
+                                    eCbEvent evt)
+{
+  PointerRNA id_ptr;
+  RNA_id_pointer_create(id, &id_ptr);
+
+  PointerRNA depsgraph_ptr;
+  RNA_pointer_create(NULL, &RNA_Depsgraph, depsgraph, &depsgraph_ptr);
+
+  PointerRNA *pointers[2] = {&id_ptr, &depsgraph_ptr};
+
+  BKE_callback_exec(bmain, pointers, 2, evt);
+}
+
 void BKE_callback_add(bCallbackFuncStore *funcstore, eCbEvent evt)
 {
   ListBase *lb = &callback_slots[evt];
diff --git a/source/blender/blenkernel/intern/scene.c b/source/blender/blenkernel/intern/scene.c
index aa812dff877..cd10713897a 100644
--- a/source/blender/blenkernel/intern/scene.c
+++ b/source/blender/blenkernel/intern/scene.c
@@ -1309,7 +1309,7 @@ static void scene_graph_update_tagged(Depsgraph *depsgraph, Main *bmain, bool on
 
   bool run_callbacks = DEG_id_type_any_updated(depsgraph);
   if (run_callbacks) {
-    BKE_callback_exec(bmain, &scene->id, BKE_CB_EVT_DEPSGRAPH_UPDATE_PRE);
+    BKE_callback_exec_id(bmain, &scene->id, BKE_CB_EVT_DEPSGRAPH_UPDATE_PRE);
   }
 
   for (int pass = 0; pass < 2; pass++) {
@@ -1327,7 +1327,8 @@ static void scene_graph_update_tagged(Depsgraph *depsgraph, Main *bmain, bool on
     BKE_scene_update_sound(depsgraph, bmain);
     /* Notify python about depsgraph update. */
     if (run_callbacks) {
-      BKE_callback_exec(bmain, &scene->id, BKE_CB_EVT_DEPSGRAPH_UPDATE_POST);
+      BKE_callback_exec_id_depsgraph(
+          bmain, &scene->id, depsgraph, BKE_CB_EVT_DEPSGRAPH_UPDATE_POST);
     }
     /* Inform editors about possible changes. */
     DEG_ids_check_recalc(bmain, depsgraph, scene, view_layer, false);
@@ -1362,7 +1363,7 @@ void BKE_scene_graph_update_for_newframe(Depsgraph *depsgraph, Main *bmain)
   ViewLayer *view_layer = DEG_get_input_view_layer(depsgraph);
 
   /* Keep this first. */
-  BKE_callback_exec(bmain, &scene->id, BKE_CB_EVT_FRAME_CHANGE_PRE);
+  BKE_callback_exec_id(bmain, &scene->id, BKE_CB_EVT_FRAME_CHANGE_PRE);
 
   for (int pass = 0; pass < 2; pass++) {
     /* Update animated image textures for particles, modifiers, gpu, etc,
@@ -1384,7 +1385,7 @@ void BKE_scene_graph_update_for_newframe(Depsgraph *depsgraph, Main *bmain)
 
     /* Notify editors and python about recalc. */
     if (pass == 0) {
-      BKE_callback_exec(bmain, &scene->id, BKE_CB_EVT_FRAME_CHANGE_POST);
+      BKE_callback_exec_id_depsgraph(bmain, &scene->id, depsgraph, BKE_CB_EVT_FRAME_CHANGE_POST);
     }
 
     /* Inform editors about possible changes. */