Record const state of input list

diff --git a/src/lib/util/dcursor.h b/src/lib/util/dcursor.h
index 6f1e49aca3042e51c51a6a138d6254b985d5d990..c72643594b8ef3ef011c986294371c29327e3c37 100644 (file)
--- a/src/lib/util/dcursor.h
+++ b/src/lib/util/dcursor.h
@@ -82,6 +82,7 @@ typedef struct {
        fr_dcursor_iter_t       iter;           //!< Iterator function.
        fr_dcursor_insert_t     insert;         //!< Callback function on insert.
        fr_dcursor_delete_t     delete;         //!< Callback function on delete.
+       bool                    is_const;       //!< The list we're iterating over is immutable.
        void                    *uctx;          //!< to pass to iterator function.
 } fr_dcursor_t;
 
@@ -613,7 +614,16 @@ static inline void fr_dcursor_free_list(fr_dcursor_t *cursor)
  *     - The first item returned by the iterator.
  */
 #define fr_dcursor_talloc_iter_init(_cursor, _head, _iter, _uctx, _type) \
-       _fr_dcursor_init(_cursor, (fr_dlist_head_t const *)_head, _iter, NULL, NULL, _uctx)
+       _fr_dcursor_init(_cursor, \
+                        _head, \
+                        _iter, \
+                        NULL, \
+                        NULL, \
+                        _Generic((_head), \
+                               fr_dlist_head_t *       : false, \
+                               fr_dlist_head_t const * : true \
+                        ), \
+                        _uctx)
 
 /** Initialise a cursor with a custom iterator
  *
@@ -627,7 +637,16 @@ static inline void fr_dcursor_free_list(fr_dcursor_t *cursor)
  *     - The first item returned by the iterator.
  */
 #define fr_dcursor_iter_init(_cursor, _head, _iter, _uctx) \
-       _fr_dcursor_init(_cursor, (fr_dlist_head_t *)_head, _iter, NULL, NULL, _uctx)
+       _fr_dcursor_init(_cursor, \
+                        _head, \
+                        _iter, \
+                        NULL, \
+                        NULL, \
+                        _Generic((_head), \
+                               fr_dlist_head_t *       : false, \
+                               fr_dlist_head_t const * : true \
+                        ), \
+                        _uctx)
 
 /** Initialise a cursor with runtime talloc type safety checks
  *
@@ -639,7 +658,16 @@ static inline void fr_dcursor_free_list(fr_dcursor_t *cursor)
  *     - The first item in the list.
  */
 #define fr_dcursor_talloc_init(_cursor, _head, _type) \
-       _fr_dcursor_init(_cursor, (fr_dlist_head_t const *)_head, NULL, NULL, NULL, NULL)
+       _fr_dcursor_init(_cursor, \
+                        _head, \
+                        NULL, \
+                        NULL, \
+                        NULL, \
+                        _Generic((_head), \
+                               fr_dlist_head_t *       : false, \
+                               fr_dlist_head_t const * : true \
+                        ), \
+                        NULL)
 
 /** Initialise a cursor
  *
@@ -650,7 +678,16 @@ static inline void fr_dcursor_free_list(fr_dcursor_t *cursor)
  *     - The first item in the list.
  */
 #define fr_dcursor_init(_cursor, _head) \
-       _fr_dcursor_init(_cursor, (fr_dlist_head_t const *)_head, NULL, NULL, NULL, NULL)
+       _fr_dcursor_init(_cursor, \
+                        _head, \
+                        NULL, \
+                        NULL, \
+                        NULL, \
+                        _Generic((_head), \
+                               fr_dlist_head_t *       : false, \
+                               fr_dlist_head_t const * : true \
+                        ), \
+                        NULL)
 
 /** Setup a cursor to iterate over attribute items in dlists
  *
@@ -659,6 +696,7 @@ static inline void fr_dcursor_free_list(fr_dcursor_t *cursor)
  * @param[in] iter     Iterator callback.
  * @param[in] insert   Callback for inserts.
  * @param[in] delete   Callback for removals.
+ * @param[in] is_const Don't allow modification of the underlying list.
  * @param[in] uctx     to pass to iterator function.
  * @return the attribute pointed to by v.
  *
@@ -666,19 +704,16 @@ static inline void fr_dcursor_free_list(fr_dcursor_t *cursor)
  */
 static inline void * CC_HINT(hot) _fr_dcursor_init(fr_dcursor_t *cursor, fr_dlist_head_t const *head,
                                     fr_dcursor_iter_t iter, fr_dcursor_insert_t insert,
-                                    fr_dcursor_delete_t delete, void const *uctx)
+                                    fr_dcursor_delete_t delete, bool is_const, void const *uctx)
 {
-       fr_dlist_head_t *v;
-
-       memcpy(&v, &head, sizeof(v));                   /* stupid const hacks */
        *cursor = (fr_dcursor_t){
-               .dlist = v,
+               .dlist = UNCONST(fr_dlist_head_t *, head),
                .iter = iter,
                .insert = insert,
                .delete = delete,
-               .prev = NULL
+               .uctx = UNCONST(void *, uctx),
+               .is_const = is_const
        };
-       memcpy(&cursor->uctx, &uctx, sizeof(cursor->uctx));
        if (!fr_dlist_empty(cursor->dlist)) return fr_dcursor_next(cursor);     /* Initialise current */
 
        return NULL;