refs_ref_iterator_begin(): new function

Extract a new function from `do_for_each_ref()`. It will be useful
elsewhere.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

2 files changed, 24 insertions, 2 deletions

diff --git a/refs.c b/refs.c
index aa461156c4..2ae18097d4 100644
--- a/refs.c
+++ b/refs.c
@@ -1230,6 +1230,18 @@ int head_ref(each_ref_fn fn, void *cb_data)
 	return head_ref_submodule(NULL, fn, cb_data);
 }
 
+struct ref_iterator *refs_ref_iterator_begin(
+		struct ref_store *refs,
+		const char *prefix, int trim, int flags)
+{
+	struct ref_iterator *iter;
+
+	iter = refs->be->iterator_begin(refs, prefix, flags);
+	iter = prefix_ref_iterator_begin(iter, prefix, trim);
+
+	return iter;
+}
+
 /*
  * Call fn for each reference in the specified submodule for which the
  * refname begins with prefix. If trim is non-zero, then trim that
@@ -1247,8 +1259,7 @@ static int do_for_each_ref(struct ref_store *refs, const char *prefix,
 	if (!refs)
 		return 0;
 
-	iter = refs->be->iterator_begin(refs, prefix, flags);
-	iter = prefix_ref_iterator_begin(iter, prefix, trim);
+	iter = refs_ref_iterator_begin(refs, prefix, trim, flags);
 
 	return do_for_each_ref_iterator(iter, fn, cb_data);
 }
diff --git a/refs/refs-internal.h b/refs/refs-internal.h
index 6ee9f20dbc..545989ae7f 100644
--- a/refs/refs-internal.h
+++ b/refs/refs-internal.h
@@ -336,6 +336,17 @@ struct ref_iterator *empty_ref_iterator_begin(void);
 int is_empty_ref_iterator(struct ref_iterator *ref_iterator);
 
 /*
+ * Return an iterator that goes over each reference in `refs` for
+ * which the refname begins with prefix. If trim is non-zero, then
+ * trim that many characters off the beginning of each refname. flags
+ * can be DO_FOR_EACH_INCLUDE_BROKEN to include broken references in
+ * the iteration.
+ */
+struct ref_iterator *refs_ref_iterator_begin(
+		struct ref_store *refs,
+		const char *prefix, int trim, int flags);
+
+/*
  * A callback function used to instruct merge_ref_iterator how to
  * interleave the entries from iter0 and iter1. The function should
  * return one of the constants defined in enum iterator_selection. It