[PATCH 1/6] vclock: allow to use const vclock as search key

[Vladimir Davydov <vdavydov.dev@gmail.com>]

vclockset_psearch() and friends never modify the vclock used as a search
key, but the compiler will not allow to pass const struct vclock to any
of those functions. Fix this.
---
 src/box/vclock.c | 4 +++-
 src/box/vclock.h | 5 +++--
 2 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/src/box/vclock.c b/src/box/vclock.c
index b5eb2800..3c4b3204 100644
--- a/src/box/vclock.c
+++ b/src/box/vclock.c
@@ -206,4 +206,6 @@ vclockset_node_compare(const struct vclock *a, const struct vclock *b)
 	return res;
 }
 
-rb_gen(, vclockset_, vclockset_t, struct vclock, link, vclockset_node_compare);
+rb_gen_ext_key(, vclockset_, vclockset_t, struct vclock, link,
+	       vclockset_node_compare, const struct vclock *,
+	       vclockset_node_compare);
diff --git a/src/box/vclock.h b/src/box/vclock.h
index 111e2916..d90f5697 100644
--- a/src/box/vclock.h
+++ b/src/box/vclock.h
@@ -271,7 +271,8 @@ vclock_compare(const struct vclock *a, const struct vclock *b)
  * @brief vclockset - a set of vclocks
  */
 typedef rb_tree(struct vclock) vclockset_t;
-rb_proto(, vclockset_, vclockset_t, struct vclock);
+rb_proto_ext_key(, vclockset_, vclockset_t, struct vclock,
+		 const struct vclock *);
 
 /**
  * A proximity search in a set of vclock objects.
@@ -283,7 +284,7 @@ rb_proto(, vclockset_, vclockset_t, struct vclock);
  * @return a vclock that <= than \a key
  */
 static inline struct vclock *
-vclockset_match(vclockset_t *set, struct vclock *key)
+vclockset_match(vclockset_t *set, const struct vclock *key)
 {
 	struct vclock *match = vclockset_psearch(set, key);
 	/**
-- 
2.11.0