Fix T49775: Appending data with internal dependency cycles prevents correct clearing of linked data-blocks.

This is not a simple fix, but imho still needs to be backported to 2.78a...

1 files changed, 91 insertions, 21 deletions

diff --git a/source/blender/blenkernel/intern/library_query.c b/source/blender/blenkernel/intern/library_query.c
index 08f9c439a7a..cec7fbacd80 100644
--- a/source/blender/blenkernel/intern/library_query.c
+++ b/source/blender/blenkernel/intern/library_query.c
@@ -1029,30 +1029,32 @@ static int foreach_libblock_id_users_callback(void *user_data, ID *self_id, ID *
 {
 	IDUsersIter *iter = user_data;
 
-	/* XXX This is actually some kind of hack...
-	 * Issue is, shapekeys' 'from' ID pointer is not actually ID usage.
-	 * Maybe we should even nuke it from BKE_library_foreach_ID_link, not 100% sure yet...
-	 */
-	if ((GS(self_id->name) == ID_KE) && (((Key *)self_id)->from == *id_p)) {
-		return IDWALK_RET_NOP;
-	}
-	/* XXX another hack, for similar reasons as above one. */
-	if ((GS(self_id->name) == ID_OB) && (((Object *)self_id)->proxy_from == (Object *)*id_p)) {
-		return IDWALK_RET_NOP;
-	}
+	if (*id_p) {
+		/* XXX This is actually some kind of hack...
+		 * Issue is, shapekeys' 'from' ID pointer is not actually ID usage.
+		 * Maybe we should even nuke it from BKE_library_foreach_ID_link, not 100% sure yet...
+		 */
+		if ((GS(self_id->name) == ID_KE) && (((Key *)self_id)->from == *id_p)) {
+			return IDWALK_RET_NOP;
+		}
+		/* XXX another hack, for similar reasons as above one. */
+		if ((GS(self_id->name) == ID_OB) && (((Object *)self_id)->proxy_from == (Object *)*id_p)) {
+			return IDWALK_RET_NOP;
+		}
 
-	if (*id_p && (*id_p == iter->id)) {
+		if (*id_p == iter->id) {
 #if 0
-		printf("%s uses %s (refcounted: %d, userone: %d, used_one: %d, used_one_active: %d, indirect_usage: %d)\n",
-		       iter->curr_id->name, iter->id->name, (cb_flag & IDWALK_USER) ? 1 : 0, (cb_flag & IDWALK_USER_ONE) ? 1 : 0,
-		       (iter->id->tag & LIB_TAG_EXTRAUSER) ? 1 : 0, (iter->id->tag & LIB_TAG_EXTRAUSER_SET) ? 1 : 0,
-		       (cb_flag & IDWALK_INDIRECT_USAGE) ? 1 : 0);
+			printf("%s uses %s (refcounted: %d, userone: %d, used_one: %d, used_one_active: %d, indirect_usage: %d)\n",
+				   iter->curr_id->name, iter->id->name, (cb_flag & IDWALK_USER) ? 1 : 0, (cb_flag & IDWALK_USER_ONE) ? 1 : 0,
+				   (iter->id->tag & LIB_TAG_EXTRAUSER) ? 1 : 0, (iter->id->tag & LIB_TAG_EXTRAUSER_SET) ? 1 : 0,
+				   (cb_flag & IDWALK_INDIRECT_USAGE) ? 1 : 0);
 #endif
-		if (cb_flag & IDWALK_INDIRECT_USAGE) {
-			iter->count_indirect++;
-		}
-		else {
-			iter->count_direct++;
+			if (cb_flag & IDWALK_INDIRECT_USAGE) {
+				iter->count_indirect++;
+			}
+			else {
+				iter->count_direct++;
+			}
 		}
 	}
 
@@ -1167,3 +1169,71 @@ void BKE_library_ID_test_usages(Main *bmain, void *idv, bool *is_used_local, boo
 	*is_used_local = (iter.count_direct != 0);
 	*is_used_linked = (iter.count_indirect != 0);
 }
+
+
+static int foreach_libblock_tag_unused_linked_data_callback(void *user_data, ID *self_id, ID **id_p, int UNUSED(cb_flag))
+{
+	bool *is_changed = user_data;
+
+	if (*id_p) {
+		/* XXX This is actually some kind of hack...
+		 * Issue is, shapekeys' 'from' ID pointer is not actually ID usage.
+		 * Maybe we should even nuke it from BKE_library_foreach_ID_link, not 100% sure yet...
+		 */
+		if ((GS(self_id->name) == ID_KE) && (((Key *)self_id)->from == *id_p)) {
+			return IDWALK_RET_NOP;
+		}
+		/* XXX another hack, for similar reasons as above one. */
+		if ((GS(self_id->name) == ID_OB) && (((Object *)self_id)->proxy_from == (Object *)*id_p)) {
+			return IDWALK_RET_NOP;
+		}
+
+		/* If checked id is used by an assumed used ID, then it is also used and not part of any linked archipelago. */
+		if (!(self_id->tag & LIB_TAG_DOIT) && ((*id_p)->tag & LIB_TAG_DOIT)) {
+			(*id_p)->tag &= ~LIB_TAG_DOIT;
+			*is_changed = true;
+		}
+	}
+
+	return IDWALK_RET_NOP;
+}
+
+/**
+ * Detect orphaned linked data blocks (i.e. linked data not used (directly or indirectly) in any way by any local data),
+ * including complex cases like 'linked archipelagoes', i.e. linked datablocks that use each other in loops,
+ * which prevents their deletion by 'basic' usage checks...
+ *
+ * \param do_init_tag if \a true, all linked data are checked, if \a false, only linked datablocks already tagged with
+ *                    LIB_TAG_DOIT are checked.
+ */
+void BKE_library_tag_unused_linked_data(Main *bmain, const bool do_init_tag)
+{
+	ListBase *lb_array[MAX_LIBARRAY];
+
+	if (do_init_tag) {
+		int i = set_listbasepointers(bmain, lb_array);
+
+		while (i--) {
+			for (ID *id = lb_array[i]->first; id; id = id->next) {
+				if (id->lib && (id->tag & LIB_TAG_INDIRECT) != 0) {
+					id->tag |= LIB_TAG_DOIT;
+				}
+				else {
+					id->tag &= ~LIB_TAG_DOIT;
+				}
+			}
+		}
+	}
+
+	bool do_loop = true;
+	while (do_loop) {
+		int i = set_listbasepointers(bmain, lb_array);
+		do_loop = false;
+
+		while (i--) {
+			for (ID *id = lb_array[i]->first; id; id = id->next) {
+				BKE_library_foreach_ID_link(id, foreach_libblock_tag_unused_linked_data_callback, &do_loop, IDWALK_NOP);
+			}
+		}
+	}
+}