[PATCH v2 01/23] refs.c: create a public function for is_refname_available

[Ronnie Sahlberg <sahlberg@google.com>]

Export a generic is_refname_available() function. We will need this
as a public shared function later when we add additional refs backends
since we want to keep using the same rules for ref naming across
all backends.

Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
---
 refs.c | 29 ++++++++++++++++++-----------
 refs.h |  6 ++++++
 2 files changed, 24 insertions(+), 11 deletions(-)

diff --git a/refs.c b/refs.c
index 7e13c0f..4a22513 100644
--- a/refs.c
+++ b/refs.c
@@ -830,9 +830,9 @@ static int name_conflict_fn(struct ref_entry *entry, void *cb_data)
  * operation). skip contains a list of refs we want to skip checking for
  * conflicts with.
  */
-static int is_refname_available(const char *refname,
-				struct ref_dir *dir,
-				const char **skip, int skipnum)
+static int is_refname_available_dir(const char *refname,
+				    struct ref_dir *dir,
+				    const char **skip, int skipnum)
 {
 	struct name_conflict_cb data;
 	data.refname = refname;
@@ -1238,6 +1238,18 @@ static struct ref_dir *get_loose_refs(struct ref_cache *refs)
 	return get_ref_dir(refs->loose);
 }
 
+int is_refname_available(const char *refname, const char **skip, int skipnum)
+{
+	if (!is_refname_available_dir(refname, get_packed_refs(&ref_cache),
+				      skip, skipnum))
+		return 0;
+
+	if (!is_refname_available_dir(refname, get_loose_refs(&ref_cache),
+				      skip, skipnum))
+		return 0;
+	return 1;
+}
+
 /* We allow "recursive" symbolic refs. Only within reason, though */
 #define MAXDEPTH 5
 #define MAXREFLEN (1024)
@@ -2168,8 +2180,8 @@ static struct ref_lock *lock_ref_sha1_basic(const char *refname,
 	 * name is a proper prefix of our refname.
 	 */
 	if (missing &&
-	     !is_refname_available(refname, get_packed_refs(&ref_cache),
-				   skip, skipnum)) {
+	     !is_refname_available_dir(refname, get_packed_refs(&ref_cache),
+				       skip, skipnum)) {
 		last_errno = ENOTDIR;
 		goto error_return;
 	}
@@ -2676,12 +2688,7 @@ int rename_ref(const char *oldrefname, const char *newrefname, const char *logms
 		return 1;
 	}
 
-	if (!is_refname_available(newrefname, get_packed_refs(&ref_cache),
-				  &oldrefname, 1))
-		return 1;
-
-	if (!is_refname_available(newrefname, get_loose_refs(&ref_cache),
-				  &oldrefname, 1))
+	if (!is_refname_available(newrefname, &oldrefname, 1))
 		return 1;
 
 	log = reflog_exists(oldrefname);
diff --git a/refs.h b/refs.h
index f44b5c8..d526da0 100644
--- a/refs.h
+++ b/refs.h
@@ -131,6 +131,12 @@ extern int ref_exists(const char *);
 extern int is_branch(const char *refname);
 
 /*
+ * Check that a particular refname is available for creation. skip contains
+ * a list of refnames to exclude from the refname collision tests.
+ */
+int is_refname_available(const char *refname, const char **skip, int skipnum);
+
+/*
  * If refname is a non-symbolic reference that refers to a tag object,
  * and the tag can be (recursively) dereferenced to a non-tag object,
  * store the SHA1 of the referred-to object to sha1 and return 0.  If
-- 
2.0.1.556.g3edca4c