ID-Remap - Step one: core work (cleanup and rework of generic ID datablock handling).

This commit changes a lot of how IDs are handled internally, especially the unlinking/freeing
processes. So far, this was very fuzy, to summarize cleanly deleting or replacing a datablock
was pretty much impossible, except for a few special cases.

Also, unlinking was handled by each datatype, in a rather messy and prone-to-errors way (quite
a few ID usages were missed or wrongly handled that way).

One of the main goal of id-remap branch was to cleanup this, and fatorize ID links handling
by using library_query utils to allow generic handling of those, which is now the case
(now, generic ID links handling is only "knwon" from readfile.c and library_query.c).

This commit also adds backends to allow live replacement and deletion of datablocks in Blender
(so-called 'remapping' process, where we replace all usages of a given ID pointer by a new one,
or NULL one in case of unlinking).

This will allow nice new features, like ability to easily reload or relocate libraries, real immediate
deletion of datablocks in blender, replacement of one datablock by another, etc.
Some of those are for next commits.

A word of warning: this commit is highly risky, because it affects potentially a lot in Blender core.
Though it was tested rather deeply, being totally impossible to check all possible ID usage cases,
it's likely there are some remaining issues and bugs in new code... Please report them! ;)

Review task: D2027 (https://developer.blender.org/D2027).
Reviewed by campbellbarton, thanks a bunch.

1 files changed, 7 insertions, 31 deletions

diff --git a/source/blender/blenkernel/intern/node.c b/source/blender/blenkernel/intern/node.c
index 2b381f6ff0b..d78ddc41e97 100644
--- a/source/blender/blenkernel/intern/node.c
+++ b/source/blender/blenkernel/intern/node.c
@@ -1782,21 +1782,21 @@ static void free_localized_node_groups(bNodeTree *ntree)
 	for (node = ntree->nodes.first; node; node = node->next) {
 		if (node->type == NODE_GROUP && node->id) {
 			bNodeTree *ngroup = (bNodeTree *)node->id;
-			ntreeFreeTree_ex(ngroup, false);
+			ntreeFreeTree(ngroup);
 			MEM_freeN(ngroup);
 		}
 	}
 }
 
-/* do not free ntree itself here, BKE_libblock_free calls this function too */
-void ntreeFreeTree_ex(bNodeTree *ntree, const bool do_id_user)
+/** Free (or release) any data used by this nodetree (does not free the nodetree itself). */
+void ntreeFreeTree(bNodeTree *ntree)
 {
 	bNodeTree *tntree;
 	bNode *node, *next;
 	bNodeSocket *sock, *nextsock;
-	
-	if (ntree == NULL) return;
-	
+
+	BKE_animdata_free((ID *)ntree, false);
+
 	/* XXX hack! node trees should not store execution graphs at all.
 	 * This should be removed when old tree types no longer require it.
 	 * Currently the execution data for texture nodes remains in the tree
@@ -1820,29 +1820,10 @@ void ntreeFreeTree_ex(bNodeTree *ntree, const bool do_id_user)
 	/* unregister associated RNA types */
 	ntreeInterfaceTypeFree(ntree);
 	
-	BKE_animdata_free((ID *)ntree);
-	
-	id_us_min((ID *)ntree->gpd);
-
 	BLI_freelistN(&ntree->links);   /* do first, then unlink_node goes fast */
 	
 	for (node = ntree->nodes.first; node; node = next) {
 		next = node->next;
-
-		/* ntreeUserIncrefID inline */
-
-		/* XXX, this is correct, however when freeing the entire database
-		 * this ends up accessing freed data which isn't properly unlinking
-		 * its self from scene nodes, SO - for now prefer invalid usercounts
-		 * on free rather then bad memory access - Campbell */
-#if 0
-		if (do_id_user) {
-			id_us_min(node->id);
-		}
-#else
-		(void)do_id_user;
-#endif
-
 		node_free_node_ex(ntree, node, false, false);
 	}
 
@@ -1874,11 +1855,6 @@ void ntreeFreeTree_ex(bNodeTree *ntree, const bool do_id_user)
 		BKE_libblock_free_data(G.main, &ntree->id);
 	}
 }
-/* same as ntreeFreeTree_ex but always manage users */
-void ntreeFreeTree(bNodeTree *ntree)
-{
-	ntreeFreeTree_ex(ntree, true);
-}
 
 void ntreeFreeCache(bNodeTree *ntree)
 {
@@ -2165,7 +2141,7 @@ void ntreeLocalMerge(bNodeTree *localtree, bNodeTree *ntree)
 		if (ntree->typeinfo->local_merge)
 			ntree->typeinfo->local_merge(localtree, ntree);
 		
-		ntreeFreeTree_ex(localtree, false);
+		ntreeFreeTree(localtree);
 		MEM_freeN(localtree);
 	}
 }