Outliner: Added new mode for displaying "orphaned" datablocks

Orphaned datablocks are those which have either:
* 0 users
* A "fake" user only

In the case of the former, they will be quietly discarded from the file on the next
save + reload. Hence, it is helpful to have a view where you can confirm which ones
fall into this category and might be worth saving.

We also include datablocks with a fake user only so that datablocks given a user
above can have that easily turned off again (in case the user makes a mistake).
Another benefit of showing these is that it become easier to remove fake users from
datablocks you no longer want retained without having to hunt for them.

3 files changed, 44 insertions, 0 deletions

diff --git a/source/blender/editors/space_outliner/outliner_tree.c b/source/blender/editors/space_outliner/outliner_tree.c
index c956d77d64a..d176fd29867 100644
--- a/source/blender/editors/space_outliner/outliner_tree.c
+++ b/source/blender/editors/space_outliner/outliner_tree.c
@@ -1474,6 +1474,7 @@ static int outliner_filter_tree(SpaceOops *soops, ListBase *lb)
 	return (BLI_listbase_is_empty(lb) == false);
 }
 
+// XXX: move this above all the filters?
 static void outliner_add_library_contents(Main *mainvar, SpaceOops *soops, TreeElement *te, Library *lib)
 {
 	TreeElement *ten;
@@ -1509,6 +1510,43 @@ static void outliner_add_library_contents(Main *mainvar, SpaceOops *soops, TreeE
 	
 }
 
+// XXX: move this above all the filters?
+static void outliner_add_orphaned_datablocks(Main *mainvar, SpaceOops *soops)
+{
+	TreeElement *ten;
+	ListBase *lbarray[MAX_LIBARRAY];
+	int a, tot;
+	
+	tot = set_listbasepointers(mainvar, lbarray);
+	for (a = 0; a < tot; a++) {
+		if (lbarray[a]->first) {
+			ID *id = lbarray[a]->first;
+			
+			/* check if there are any datablocks of this type which are orphans */
+			for (; id; id = id->next) {
+				if (ID_REAL_USERS(id) <= 0)
+					break;
+			}
+			
+			if (id) {
+				/* header for this type of datablock */
+				ten = outliner_add_element(soops, &soops->tree, (void *)lbarray[a], NULL, TSE_ID_BASE, 0);
+				ten->directdata = lbarray[a];
+				
+				ten->name = (char *)BKE_idcode_to_name_plural(GS(id->name));
+				if (ten->name == NULL)
+					ten->name = "UNKNOWN";
+				
+				/* add the orphaned datablocks - these will not be added with any subtrees attached */
+				for (id = lbarray[a]->first; id; id = id->next) {
+					if (ID_REAL_USERS(id) <= 0)
+						outliner_add_element(soops, &ten->subtree, id, ten, 0, 0);
+				}
+			}
+		}
+	}
+}
+
 
 /* ======================================================= */
 /* Main Tree Building API */
@@ -1713,6 +1751,9 @@ void outliner_build_tree(Main *mainvar, Scene *scene, SpaceOops *soops)
 			tselem->flag &= ~TSE_CLOSED;
 		}
 	}
+	else if (soops->outlinevis == SO_ID_ORPHANS) {
+		outliner_add_orphaned_datablocks(mainvar, soops);
+	}
 	else {
 		ten = outliner_add_element(soops, &soops->tree, OBACT, NULL, 0, 0);
 		if (ten) ten->directdata = BASACT;
diff --git a/source/blender/makesdna/DNA_space_types.h b/source/blender/makesdna/DNA_space_types.h
index f41de65f68e..41fbb26c50c 100644
--- a/source/blender/makesdna/DNA_space_types.h
+++ b/source/blender/makesdna/DNA_space_types.h
@@ -292,6 +292,7 @@ typedef enum eSpaceOutliner_Mode {
 	SO_DATABLOCKS = 11,
 	SO_USERDEF = 12,
 	/* SO_KEYMAP = 13, */        /* deprecated! */
+	SO_ID_ORPHANS = 14,
 } eSpaceOutliner_Mode;
 
 /* SpaceOops->storeflag */
diff --git a/source/blender/makesrna/intern/rna_space.c b/source/blender/makesrna/intern/rna_space.c
index 816d4acd729..ef5a6c2a51c 100644
--- a/source/blender/makesrna/intern/rna_space.c
+++ b/source/blender/makesrna/intern/rna_space.c
@@ -1841,6 +1841,8 @@ static void rna_def_space_outliner(BlenderRNA *brna)
 		{SO_LIBRARIES, "LIBRARIES", 0, "Blender File", "Display data of current file and linked libraries"},
 		{SO_DATABLOCKS, "DATABLOCKS", 0, "Datablocks", "Display all raw datablocks"},
 		{SO_USERDEF, "USER_PREFERENCES", 0, "User Preferences", "Display the user preference datablocks"},
+		{SO_ID_ORPHANS, "ORPHANED_DATABLOCKS", 0, "Orphaned Datablocks", 
+		                "Display datablocks which are unused and/or will be lost when the file is reloaded"},
 		{0, NULL, 0, NULL, NULL}
 	};