Refactor ID copying (and to some extent, ID freeing).

This will allow much finer controll over how we copy data-blocks, from
full copy in Main database, to "lighter" ones (out of Main, inside an
already allocated datablock, etc.).

This commit also transfers a llot of what was previously handled by
per-ID-type custom code to generic ID handling code in BKE_library.
Hopefully will avoid in future inconsistencies and missing bits we had
all over the codebase in the past.

It also adds missing copying handling for a few types, most notably
Scene (which where using a fully customized handling previously).

Note that the type of allocation used during copying (regular in Main,
allocated but outside of Main, or not allocated by ID handling code at
all) is stored in ID's, which allows to handle them correctly when
freeing. This needs to be taken care of with caution when doing 'weird'
unusual things with ID copying and/or allocation!

As a final note, while rather noisy, this commit will hopefully not
break too much existing branches, old 'API' has been kept for the main
part, as a wrapper around new code. Cleaning it up will happen later.

Design task : T51804
Phab Diff: D2714

1 files changed, 15 insertions, 9 deletions

diff --git a/source/blender/blenkernel/intern/constraint.c b/source/blender/blenkernel/intern/constraint.c
index 07a6b304dff..c05feb7faf4 100644
--- a/source/blender/blenkernel/intern/constraint.c
+++ b/source/blender/blenkernel/intern/constraint.c
@@ -4737,29 +4737,30 @@ static void con_fix_copied_refs_cb(bConstraint *UNUSED(con), ID **idpoin, bool i
 }
 
 /* duplicate all of the constraints in a constraint stack */
-void BKE_constraints_copy(ListBase *dst, const ListBase *src, bool do_extern)
+void BKE_constraints_copy_ex(ListBase *dst, const ListBase *src, const int flag, bool do_extern)
 {
 	bConstraint *con, *srccon;
-	
+
 	BLI_listbase_clear(dst);
 	BLI_duplicatelist(dst, src);
-	
+
 	for (con = dst->first, srccon = src->first; con && srccon; srccon = srccon->next, con = con->next) {
 		const bConstraintTypeInfo *cti = BKE_constraint_typeinfo_get(con);
-		
+
 		/* make a new copy of the constraint's data */
 		con->data = MEM_dupallocN(con->data);
-		
+
 		/* only do specific constraints if required */
 		if (cti) {
 			/* perform custom copying operations if needed */
 			if (cti->copy_data)
 				cti->copy_data(con, srccon);
-				
-			/* fix usercounts for all referenced data in referenced data */
-			if (cti->id_looper)
+
+			/* Fix usercounts for all referenced data that need it. */
+			if (cti->id_looper && (flag & LIB_ID_CREATE_NO_USER_REFCOUNT) == 0) {
 				cti->id_looper(con, con_fix_copied_refs_cb, NULL);
-			
+			}
+
 			/* for proxies we don't want to make extern */
 			if (do_extern) {
 				/* go over used ID-links for this constraint to ensure that they are valid for proxies */
@@ -4770,6 +4771,11 @@ void BKE_constraints_copy(ListBase *dst, const ListBase *src, bool do_extern)
 	}
 }
 
+void BKE_constraints_copy(ListBase *dst, const ListBase *src, bool do_extern)
+{
+	BKE_constraints_copy_ex(dst, src, 0, do_extern);
+}
+
 /* ......... */
 
 bConstraint *BKE_constraints_find_name(ListBase *list, const char *name)