+\f
+/* Face-merge cycle checking. */
+
+/* A `named merge point' is simply a point during face-merging where we
+ look up a face by name. We keep a stack of which named lookups we're
+ currently processing so that we can easily detect cycles, using a
+ linked- list of struct named_merge_point structures, typically
+ allocated on the stack frame of the named lookup functions which are
+ active (so no consing is required). */
+struct named_merge_point
+{
+ Lisp_Object face_name;
+ struct named_merge_point *prev;
+};
+
+
+/* If a face merging cycle is detected for FACE_NAME, return 0,
+ otherwise add NEW_NAMED_MERGE_POINT, which is initialized using
+ FACE_NAME, as the head of the linked list pointed to by
+ NAMED_MERGE_POINTS, and return 1. */
+
+static INLINE int
+push_named_merge_point (struct named_merge_point *new_named_merge_point,
+ Lisp_Object face_name,
+ struct named_merge_point **named_merge_points)
+{
+ struct named_merge_point *prev;
+
+ for (prev = *named_merge_points; prev; prev = prev->prev)
+ if (EQ (face_name, prev->face_name))
+ return 0;
+
+ new_named_merge_point->face_name = face_name;
+ new_named_merge_point->prev = *named_merge_points;
+
+ *named_merge_points = new_named_merge_point;
+
+ return 1;
+}
+
+\f
+
+