hashmap: use *_entry APIs for iteration

Inspired by list_for_each_entry in the Linux kernel.
Once again, these are somewhat compromised usability-wise
by compilers lacking __typeof__ support.

Signed-off-by: Eric Wong <e@80x24.org>
Reviewed-by: Derrick Stolee <stolee@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 13 insertions, 2 deletions

diff --git a/hashmap.h b/hashmap.h
index 8f5c163d56..8d4b3907b4 100644
--- a/hashmap.h
+++ b/hashmap.h
@@ -382,16 +382,27 @@ struct hashmap_iter {
 void hashmap_iter_init(struct hashmap *map, struct hashmap_iter *iter);
 
 /* Returns the next hashmap_entry, or NULL if there are no more entries. */
-void *hashmap_iter_next(struct hashmap_iter *iter);
+struct hashmap_entry *hashmap_iter_next(struct hashmap_iter *iter);
 
 /* Initializes the iterator and returns the first entry, if any. */
-static inline void *hashmap_iter_first(struct hashmap *map,
+static inline struct hashmap_entry *hashmap_iter_first(struct hashmap *map,
 		struct hashmap_iter *iter)
 {
 	hashmap_iter_init(map, iter);
 	return hashmap_iter_next(iter);
 }
 
+#define hashmap_iter_next_entry(iter, type, member) \
+	container_of_or_null(hashmap_iter_next(iter), type, member)
+
+#define hashmap_iter_first_entry(map, iter, type, member) \
+	container_of_or_null(hashmap_iter_first(map, iter), type, member)
+
+#define hashmap_for_each_entry(map, iter, var, type, member) \
+	for (var = hashmap_iter_first_entry(map, iter, type, member); \
+		var; \
+		var = hashmap_iter_next_entry(iter, type, member))
+
 /*
  * returns a @pointer of @type matching @keyvar, or NULL if nothing found.
  * @keyvar is a pointer of @type