Cleanup: Main id looping: add FOREACH_MAIN_LISTBASE macro.

We don't want to use flow control like `break` statement into the basic
`FOREACH_MAIN_ID` macro, as this is a nested loop.

When refined behavior is needed (like breaking whole iteration, or just
skipping to next ID type), FOREACH_MAIN_LISTBASE and
FOREACH_MAIN_LISTBASE_ID macros should be used instead.

Based on D4382 by @campbellbarton
(Other potential solution, using flow control macros: D4384).

1 files changed, 46 insertions, 41 deletions

diff --git a/source/blender/python/intern/bpy_rna_id_collection.c b/source/blender/python/intern/bpy_rna_id_collection.c
index 31b135fe933..7a5849f818d 100644
--- a/source/blender/python/intern/bpy_rna_id_collection.c
+++ b/source/blender/python/intern/bpy_rna_id_collection.c
@@ -159,6 +159,7 @@ static PyObject *bpy_user_map(PyObject *UNUSED(self), PyObject *args, PyObject *
 #else
 	Main *bmain = G_MAIN;  /* XXX Ugly, but should work! */
 #endif
+	ListBase *lb;
 	ID *id;
 
 	PyObject *subset = NULL;
@@ -223,57 +224,61 @@ static PyObject *bpy_user_map(PyObject *UNUSED(self), PyObject *args, PyObject *
 
 	data_cb.types_bitmap = key_types_bitmap;
 
-	FOREACH_MAIN_ID_BEGIN(bmain, id)
+	FOREACH_MAIN_LISTBASE_BEGIN(bmain, lb)
 	{
-		/* We cannot skip here in case we have some filter on key types... */
-		if (key_types_bitmap == NULL && val_types_bitmap != NULL) {
-			if (!id_check_type(id, val_types_bitmap)) {
-				break;  /* Break iter on that type of IDs, continues with next ID type. */
+		FOREACH_MAIN_LISTBASE_ID_BEGIN(lb, id)
+		{
+			/* We cannot skip here in case we have some filter on key types... */
+			if (key_types_bitmap == NULL && val_types_bitmap != NULL) {
+				if (!id_check_type(id, val_types_bitmap)) {
+					break;
+				}
 			}
-		}
 
-		/* One-time init, ID is just used as placeholder here, we abuse this in iterator callback
-		 * to avoid having to rebuild a complete bpyrna object each time for the key searching
-		 * (where only ID pointer value is used). */
-		if (data_cb.py_id_key_lookup_only == NULL) {
-			data_cb.py_id_key_lookup_only = pyrna_id_CreatePyObject(id);
-		}
+			/* One-time init, ID is just used as placeholder here, we abuse this in iterator callback
+			 * to avoid having to rebuild a complete bpyrna object each time for the key searching
+			 * (where only ID pointer value is used). */
+			if (data_cb.py_id_key_lookup_only == NULL) {
+				data_cb.py_id_key_lookup_only = pyrna_id_CreatePyObject(id);
+			}
 
-		if (!data_cb.is_subset &&
-		    /* We do not want to pre-add keys of flitered out types. */
-		    (key_types_bitmap == NULL || id_check_type(id, key_types_bitmap)) &&
-		    /* We do not want to pre-add keys when we have filter on value types, but not on key types. */
-		    (val_types_bitmap == NULL || key_types_bitmap != NULL))
-		{
-			PyObject *key = data_cb.py_id_key_lookup_only;
-			PyObject *set;
-
-			RNA_id_pointer_create(id, &((BPy_StructRNA *)key)->ptr);
-
-			/* We have to insert the key now, otherwise ID unused would be missing from final dict... */
-			if ((set = PyDict_GetItem(data_cb.user_map, key)) == NULL) {
-				/* Cannot use our placeholder key here! */
-				key = pyrna_id_CreatePyObject(id);
-				set = PySet_New(NULL);
-				PyDict_SetItem(data_cb.user_map, key, set);
-				Py_DECREF(set);
-				Py_DECREF(key);
+			if (!data_cb.is_subset &&
+			    /* We do not want to pre-add keys of flitered out types. */
+			    (key_types_bitmap == NULL || id_check_type(id, key_types_bitmap)) &&
+			    /* We do not want to pre-add keys when we have filter on value types, but not on key types. */
+			    (val_types_bitmap == NULL || key_types_bitmap != NULL))
+			{
+				PyObject *key = data_cb.py_id_key_lookup_only;
+				PyObject *set;
+
+				RNA_id_pointer_create(id, &((BPy_StructRNA *)key)->ptr);
+
+				/* We have to insert the key now, otherwise ID unused would be missing from final dict... */
+				if ((set = PyDict_GetItem(data_cb.user_map, key)) == NULL) {
+					/* Cannot use our placeholder key here! */
+					key = pyrna_id_CreatePyObject(id);
+					set = PySet_New(NULL);
+					PyDict_SetItem(data_cb.user_map, key, set);
+					Py_DECREF(set);
+					Py_DECREF(key);
+				}
 			}
-		}
 
-		if (val_types_bitmap != NULL && !id_check_type(id, val_types_bitmap)) {
-			continue;
-		}
+			if (val_types_bitmap != NULL && !id_check_type(id, val_types_bitmap)) {
+				continue;
+			}
 
-		data_cb.id_curr = id;
-		BKE_library_foreach_ID_link(NULL, id, foreach_libblock_id_user_map_callback, &data_cb, IDWALK_CB_NOP);
+			data_cb.id_curr = id;
+			BKE_library_foreach_ID_link(NULL, id, foreach_libblock_id_user_map_callback, &data_cb, IDWALK_CB_NOP);
 
-		if (data_cb.py_id_curr) {
-			Py_DECREF(data_cb.py_id_curr);
-			data_cb.py_id_curr = NULL;
+			if (data_cb.py_id_curr) {
+				Py_DECREF(data_cb.py_id_curr);
+				data_cb.py_id_curr = NULL;
+			}
 		}
+		FOREACH_MAIN_LISTBASE_ID_END;
 	}
-	FOREACH_MAIN_ID_END;
+	FOREACH_MAIN_LISTBASE_ID_END;
 
 	ret = data_cb.user_map;