Workspaces: reference count screens, otherwise they are never freed.

They are not directly accessible in the UI anymore, it's the workspaces
that we always keep until they are manually deleted now.

5 files changed, 19 insertions, 17 deletions

diff --git a/source/blender/blenkernel/intern/library_query.c b/source/blender/blenkernel/intern/library_query.c
index c569f43e7f4..27f0b653347 100644
--- a/source/blender/blenkernel/intern/library_query.c
+++ b/source/blender/blenkernel/intern/library_query.c
@@ -950,7 +950,7 @@ void BKE_library_foreach_ID_link(Main *bmain, ID *id, LibraryIDLinkCallback call
 
 					/* CALLBACK_INVOKE expects an actual pointer, not a variable holding the pointer.
 					 * However we can't acess layout->screen here since we are outside the workspace project. */
-					CALLBACK_INVOKE(screen, IDWALK_CB_NOP);
+					CALLBACK_INVOKE(screen, IDWALK_CB_USER);
 					/* allow callback to set a different screen */
 					BKE_workspace_layout_screen_set(layout, screen);
 				}
diff --git a/source/blender/blenkernel/intern/workspace.c b/source/blender/blenkernel/intern/workspace.c
index a5e93c8d765..2829708391f 100644
--- a/source/blender/blenkernel/intern/workspace.c
+++ b/source/blender/blenkernel/intern/workspace.c
@@ -243,6 +243,7 @@ WorkSpaceLayout *BKE_workspace_layout_add(
 	UNUSED_VARS(bmain);
 #endif
 	layout->screen = screen;
+	id_us_plus(&layout->screen->id);
 	workspace_layout_name_set(workspace, layout, name);
 	BLI_addtail(&workspace->layouts, layout);
 
@@ -253,7 +254,8 @@ void BKE_workspace_layout_remove(
         Main *bmain,
         WorkSpace *workspace, WorkSpaceLayout *layout)
 {
-	BKE_libblock_free(bmain, BKE_workspace_layout_screen_get(layout));
+	id_us_min(&layout->screen->id);
+	BKE_libblock_free(bmain, layout->screen);
 	BLI_freelinkN(&workspace->layouts, layout);
 }
 
diff --git a/source/blender/blenloader/intern/readfile.c b/source/blender/blenloader/intern/readfile.c
index 810bc466275..b774bb8d1f6 100644
--- a/source/blender/blenloader/intern/readfile.c
+++ b/source/blender/blenloader/intern/readfile.c
@@ -2949,15 +2949,13 @@ static void lib_link_workspaces(FileData *fd, Main *bmain)
 		id_us_ensure_real(id);
 
 		for (WorkSpaceLayout *layout = layouts->first, *layout_next; layout; layout = layout_next) {
-			bScreen *screen = newlibadr(fd, id->lib, BKE_workspace_layout_screen_get(layout));
+			layout->screen = newlibadr_us(fd, id->lib, layout->screen);
 
 			layout_next = layout->next;
-			if (screen) {
-				BKE_workspace_layout_screen_set(layout, screen);
-
+			if (layout->screen) {
 				if (ID_IS_LINKED(id)) {
-					screen->winid = 0;
-					if (screen->temp) {
+					layout->screen->winid = 0;
+					if (layout->screen->temp) {
 						/* delete temp layouts when appending */
 						BKE_workspace_layout_remove(bmain, workspace, layout);
 					}
@@ -7251,7 +7249,6 @@ static void lib_link_screen(FileData *fd, Main *main)
 	for (bScreen *sc = main->screen.first; sc; sc = sc->id.next) {
 		if (sc->id.tag & LIB_TAG_NEED_LINK) {
 			IDP_LibLinkProperty(sc->id.properties, fd);
-			id_us_ensure_real(&sc->id);
 
 			/* deprecated, but needed for versioning (will be NULL'ed then) */
 			sc->scene = newlibadr(fd, sc->id.lib, sc->scene);
diff --git a/source/blender/blenloader/intern/writefile.c b/source/blender/blenloader/intern/writefile.c
index 57aa5111add..16bc845a3e9 100644
--- a/source/blender/blenloader/intern/writefile.c
+++ b/source/blender/blenloader/intern/writefile.c
@@ -3005,15 +3005,18 @@ static void write_windowmanager(WriteData *wd, wmWindowManager *wm)
 
 static void write_screen(WriteData *wd, bScreen *sc)
 {
-	/* write LibData */
-	/* in 2.50+ files, the file identifier for screens is patched, forward compatibility */
-	writestruct(wd, ID_SCRN, bScreen, 1, sc);
-	write_iddata(wd, &sc->id);
+	/* Screens are reference counted, only saved if used by a workspace. */
+	if (sc->id.us > 0 || wd->use_memfile) {
+		/* write LibData */
+		/* in 2.50+ files, the file identifier for screens is patched, forward compatibility */
+		writestruct(wd, ID_SCRN, bScreen, 1, sc);
+		write_iddata(wd, &sc->id);
 
-	write_previews(wd, sc->preview);
+		write_previews(wd, sc->preview);
 
-	/* direct data */
-	write_area_map(wd, AREAMAP_FROM_SCREEN(sc));
+		/* direct data */
+		write_area_map(wd, AREAMAP_FROM_SCREEN(sc));
+	}
 }
 
 static void write_bone(WriteData *wd, Bone *bone)
diff --git a/source/blender/makesdna/DNA_workspace_types.h b/source/blender/makesdna/DNA_workspace_types.h
index ad047a85c18..296fa8a713c 100644
--- a/source/blender/makesdna/DNA_workspace_types.h
+++ b/source/blender/makesdna/DNA_workspace_types.h
@@ -111,7 +111,7 @@ typedef struct bToolRef {
 typedef struct WorkSpaceLayout {
 	struct WorkSpaceLayout *next, *prev;
 
-	struct bScreen *screen DNA_PRIVATE_WORKSPACE;
+	struct bScreen *screen;
 	/* The name of this layout, we override the RNA name of the screen with this (but not ID name itself) */
 	char name[64] DNA_PRIVATE_WORKSPACE; /* MAX_NAME */
 } WorkSpaceLayout;