Replace of (id->lib != NULL) check by meaningful macro.

Idea is to replace hard-to-track (id->lib != NULL) 'is linked datablock' check everywhere in Blender
by a macro doing the same thing. This will allow to easily spot those checks in future, and more importantly,
to easily change it (see work done in asset-engine branch).

Note: did not touch to readfile.c, since there most of the time 'id->lib' check actually concerns the pointer,
and not a check whether ID is linked or not. Will have a closer look at it later.

Reviewers: campbellbarton, brecht, sergey

Differential Revision: https://developer.blender.org/D2082

1 files changed, 1 insertions, 1 deletions

diff --git a/source/blender/editors/interface/interface_eyedropper.c b/source/blender/editors/interface/interface_eyedropper.c
index 2cbc56b14d3..ac7b6428217 100644
--- a/source/blender/editors/interface/interface_eyedropper.c
+++ b/source/blender/editors/interface/interface_eyedropper.c
@@ -805,7 +805,7 @@ static int depthdropper_init(bContext *C, wmOperator *op)
 		RegionView3D *rv3d = CTX_wm_region_view3d(C);
 		if (rv3d && rv3d->persp == RV3D_CAMOB) {
 			View3D *v3d = CTX_wm_view3d(C);
-			if (v3d->camera && v3d->camera->data && (((ID *)v3d->camera->data)->lib == NULL)) {
+			if (v3d->camera && v3d->camera->data && !ID_IS_LINKED_DATABLOCK(v3d->camera->data)) {
 				RNA_id_pointer_create(v3d->camera->data, &ddr->ptr);
 				ddr->prop = RNA_struct_find_property(&ddr->ptr, "dof_distance");
 			}