We do not expose any functions via our public headers that would allow a
caller to initialize a reftable iterator from a merged table. Instead,
they are expected to go via the generic `reftable_table` interface,
which is somewhat roundabout.

Implement two new functions to initialize iterators for ref and log
records to plug this gap.

Signed-off-by: Patrick Steinhardt <redacted>
---
 reftable/merged.c          | 12 ++++++++++++
 reftable/reftable-merged.h |  8 ++++++++
 2 files changed, 20 insertions(+)

diff --git a/reftable/merged.c b/reftable/merged.c
index 6adce44f4b..8d78b3da71 100644
--- a/reftable/merged.c
+++ b/reftable/merged.c

@@ -254,6 +254,18 @@ void merged_table_init_iter(struct reftable_merged_table *mt,
 	iterator_from_merged_iter(it, mi);
 }

+void reftable_merged_table_init_ref_iterator(struct reftable_merged_table *mt,
+					     struct reftable_iterator *it)
+{
+	merged_table_init_iter(mt, it, BLOCK_TYPE_REF);
+}
+
+void reftable_merged_table_init_log_iterator(struct reftable_merged_table *mt,
+					     struct reftable_iterator *it)
+{
+	merged_table_init_iter(mt, it, BLOCK_TYPE_LOG);
+}
+