LibOverride: Refactor collection items 'local' helper functions.

It's easier to read and less 'weird' to check that an item is non-local
in a liboverride data-block, than the other way around. Thanks to
@sybren for noticing it.

source/blender/blenkernel/BKE_constraint.h

@@ -177,8 +177,8 @@ struct bConstraint *BKE_constraint_find_from_target(struct Object *ob,
                                                     struct bConstraintTarget *tgt,
                                                     struct bPoseChannel **r_pchan);
 
-bool BKE_constraint_is_local_in_liboverride(const struct Object *ob,
-                                            const struct bConstraint *con);
+bool BKE_constraint_is_nonlocal_in_liboverride(const struct Object *ob,
+                                               const struct bConstraint *con);
 
 struct bConstraint *BKE_constraint_add_for_object(struct Object *ob, const char *name, short type);
 struct bConstraint *BKE_constraint_add_for_pose(struct Object *ob,

source/blender/blenkernel/BKE_gpencil_modifier.h

@@ -278,8 +278,8 @@ void BKE_gpencil_modifiers_foreach_tex_link(struct Object *ob,
                                             GreasePencilTexWalkFunc walk,
                                             void *userData);
 
-bool BKE_gpencil_modifier_is_local_in_liboverride(const struct Object *ob,
-                                                  const struct GpencilModifierData *gmd);
+bool BKE_gpencil_modifier_is_nonlocal_in_liboverride(const struct Object *ob,
+                                                     const struct GpencilModifierData *gmd);
 
 typedef struct GpencilVirtualModifierData {
   ArmatureGpencilModifierData amd;

source/blender/blenkernel/BKE_modifier.h

@@ -431,7 +431,8 @@ bool BKE_modifier_is_non_geometrical(ModifierData *md);
 bool BKE_modifier_is_enabled(const struct Scene *scene,
                              struct ModifierData *md,
                              int required_mode);
-bool BKE_modifier_is_local_in_liboverride(const struct Object *ob, const struct ModifierData *md);
+bool BKE_modifier_is_nonlocal_in_liboverride(const struct Object *ob,
+                                             const struct ModifierData *md);
 void BKE_modifier_set_error(const struct Object *ob,
                             struct ModifierData *md,
                             const char *format,

source/blender/blenkernel/intern/constraint.c

@@ -5963,10 +5963,10 @@ static bConstraint *constraint_find_original_for_update(bConstraintOb *cob, bCon
  *
  * \note This check is only valid for a liboverride data-block, it always return \a true otherwise.
  */
-bool BKE_constraint_is_local_in_liboverride(const Object *ob, const bConstraint *con)
+bool BKE_constraint_is_nonlocal_in_liboverride(const Object *ob, const bConstraint *con)
 {
-  return (!ID_IS_OVERRIDE_LIBRARY(ob) ||
-          (con != NULL && (con->flag & CONSTRAINT_OVERRIDE_LIBRARY_LOCAL) != 0));
+  return (ID_IS_OVERRIDE_LIBRARY(ob) &&
+          (con == NULL || (con->flag & CONSTRAINT_OVERRIDE_LIBRARY_LOCAL) == 0));
 }
 
 /* -------- Constraints and Proxies ------- */

source/blender/blenkernel/intern/gpencil_modifier.c

@@ -531,16 +531,16 @@ void BKE_gpencil_modifier_set_error(GpencilModifierData *md, const char *_format
 }
 
 /**
- * Check whether given modifier is local when the object is a library override.
+ * Check whether given modifier is not local (i.e. from linked data) when the object is a library
+ * override.
  *
  * \param gmd May be NULL, in which case we consider it as a non-local modifier case.
- *
- * \note This check is only valid for a liboverride data-block, it always return \a true otherwise.
  */
-bool BKE_gpencil_modifier_is_local_in_liboverride(const Object *ob, const GpencilModifierData *gmd)
+bool BKE_gpencil_modifier_is_nonlocal_in_liboverride(const Object *ob,
+                                                     const GpencilModifierData *gmd)
 {
-  return (!ID_IS_OVERRIDE_LIBRARY(ob) ||
-          (gmd != NULL && (gmd->flag & eGpencilModifierFlag_OverrideLibrary_Local) != 0));
+  return (ID_IS_OVERRIDE_LIBRARY(ob) &&
+          (gmd == NULL || (gmd->flag & eGpencilModifierFlag_OverrideLibrary_Local) == 0));
 }
 
 /**

source/blender/blenkernel/intern/modifier.c

@@ -581,10 +581,10 @@ bool BKE_modifier_is_enabled(const struct Scene *scene, ModifierData *md, int re
  *
  * \note This check is only valid for a liboverride data-block, it always return \a true otherwise.
  */
-bool BKE_modifier_is_local_in_liboverride(const Object *ob, const ModifierData *md)
+bool BKE_modifier_is_nonlocal_in_liboverride(const Object *ob, const ModifierData *md)
 {
-  return (!ID_IS_OVERRIDE_LIBRARY(ob) ||
-          (md != NULL && (md->flag & eModifierFlag_OverrideLibrary_Local) != 0));
+  return (ID_IS_OVERRIDE_LIBRARY(ob) &&
+          (md == NULL || (md->flag & eModifierFlag_OverrideLibrary_Local) == 0));
 }
 
 CDMaskLink *BKE_modifier_calc_data_masks(struct Scene *scene,

source/blender/editors/object/object_constraint.c

@@ -706,8 +706,9 @@ static bool edit_constraint_poll_generic(bContext *C,
     return false;
   }
 
-  if (!is_liboverride_allowed && !BKE_constraint_is_local_in_liboverride(ob, con)) {
-    CTX_wm_operator_poll_msg_set(C, "Cannot edit constraints coming from library override");
+  if (!is_liboverride_allowed && BKE_constraint_is_nonlocal_in_liboverride(ob, con)) {
+    CTX_wm_operator_poll_msg_set(
+        C, "Cannot edit constraints coming from linked data in a library override");
     return false;
   }
 

source/blender/editors/object/object_gpencil_modifier.c

@@ -443,9 +443,9 @@ static bool gpencil_edit_modifier_poll_generic(bContext *C,
     return false;
   }
 
-  if (!is_liboverride_allowed &&
-      (mod == NULL || !BKE_gpencil_modifier_is_local_in_liboverride(ob, mod))) {
-    CTX_wm_operator_poll_msg_set(C, "Cannot edit modifiers coming from library override");
+  if (!is_liboverride_allowed && BKE_gpencil_modifier_is_nonlocal_in_liboverride(ob, mod)) {
+    CTX_wm_operator_poll_msg_set(
+        C, "Cannot edit modifiers coming from linked data in a library override");
     return false;
   }
 

source/blender/editors/object/object_modifier.c

@@ -1052,8 +1052,9 @@ bool edit_modifier_poll_generic(bContext *C,
     return false;
   }
 
-  if (!is_liboverride_allowed && !BKE_modifier_is_local_in_liboverride(ob, mod)) {
-    CTX_wm_operator_poll_msg_set(C, "Cannot edit modifiers coming from library override");
+  if (!is_liboverride_allowed && BKE_modifier_is_nonlocal_in_liboverride(ob, mod)) {
+    CTX_wm_operator_poll_msg_set(
+        C, "Cannot edit modifiers coming from linked data in a library override");
     return false;
   }