khash: rename kh_oid_t to kh_oid_set

khash lets us define a hash as either a map or a set (i.e., with no
"value" type). For the oid maps we define, "oid" is the set and
"oid_map" is the map. As the bug in the previous commit shows, it's easy
to pick the wrong one.

So let's make the names more distinct: "oid_set" and "oid_map".

An alternative naming scheme would be to actually name the type after
the key/value types. So e.g., "oid" _would_ be the set, since it has no
value type. And "oid_map" would become "oid_void" or similar (and
"oid_pos" becomes "oid_int"). That's better in some ways: it's more
regular, and a given map type can be more reasily reused in multiple
contexts (e.g., something storing an "int" that isn't a "pos"). But it's
also slightly less descriptive.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

khash.h

@@ -342,7 +342,7 @@ static inline int oid_equal(struct object_id a, struct object_id b)
 	return oideq(&a, &b);
 }
 
-KHASH_INIT(oid, struct object_id, int, 0, oid_hash, oid_equal)
+KHASH_INIT(oid_set, struct object_id, int, 0, oid_hash, oid_equal)
 
 KHASH_INIT(oid_map, struct object_id, void *, 1, oid_hash, oid_equal)
 

oidset.c

@@ -5,33 +5,33 @@ void oidset_init(struct oidset *set, size_t initial_size)
 {
 	memset(&set->set, 0, sizeof(set->set));
 	if (initial_size)
-		kh_resize_oid(&set->set, initial_size);
+		kh_resize_oid_set(&set->set, initial_size);
 }
 
 int oidset_contains(const struct oidset *set, const struct object_id *oid)
 {
-	khiter_t pos = kh_get_oid(&set->set, *oid);
+	khiter_t pos = kh_get_oid_set(&set->set, *oid);
 	return pos != kh_end(&set->set);
 }
 
 int oidset_insert(struct oidset *set, const struct object_id *oid)
 {
 	int added;
-	kh_put_oid(&set->set, *oid, &added);
+	kh_put_oid_set(&set->set, *oid, &added);
 	return !added;
 }
 
 int oidset_remove(struct oidset *set, const struct object_id *oid)
 {
-	khiter_t pos = kh_get_oid(&set->set, *oid);
+	khiter_t pos = kh_get_oid_set(&set->set, *oid);
 	if (pos == kh_end(&set->set))
 		return 0;
-	kh_del_oid(&set->set, pos);
+	kh_del_oid_set(&set->set, pos);
 	return 1;
 }
 
 void oidset_clear(struct oidset *set)
 {
-	kh_release_oid(&set->set);
+	kh_release_oid_set(&set->set);
 	oidset_init(set, 0);
 }

oidset.h

@@ -20,7 +20,7 @@
  * A single oidset; should be zero-initialized (or use OIDSET_INIT).
  */
 struct oidset {
-	kh_oid_t set;
+	kh_oid_set_t set;
 };
 
 #define OIDSET_INIT { { 0 } }
@@ -62,7 +62,7 @@ int oidset_remove(struct oidset *set, const struct object_id *oid);
 void oidset_clear(struct oidset *set);
 
 struct oidset_iter {
-	kh_oid_t *set;
+	kh_oid_set_t *set;
 	khiter_t iter;
 };