Convert many resolve_ref() calls to read_ref*() and ref_exists()

resolve_ref() may return a pointer to a static buffer, which is not
safe for long-term use because if another resolve_ref() call happens,
the buffer may be changed.  Many call sites though do not care about
this buffer. They simply check if the return value is NULL or not.

Convert all these call sites to new wrappers to reduce resolve_ref()
calls from 57 to 34. If we change resolve_ref() prototype later on
to avoid passing static buffer out, this helps reduce changes.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 16 insertions, 11 deletions

diff --git a/refs.c b/refs.c
index e69ba26b7..44c1c86e1 100644
--- a/refs.c
+++ b/refs.c
@@ -334,7 +334,7 @@ static void get_ref_dir(const char *submodule, const char *base,
 					flag |= REF_ISBROKEN;
 				}
 			} else
-				if (!resolve_ref(ref, sha1, 1, &flag)) {
+				if (read_ref_full(ref, sha1, 1, &flag)) {
 					hashclr(sha1);
 					flag |= REF_ISBROKEN;
 				}
@@ -612,13 +612,18 @@ struct ref_filter {
 	void *cb_data;
 };
 
-int read_ref(const char *ref, unsigned char *sha1)
+int read_ref_full(const char *ref, unsigned char *sha1, int reading, int *flags)
 {
-	if (resolve_ref(ref, sha1, 1, NULL))
+	if (resolve_ref(ref, sha1, reading, flags))
 		return 0;
 	return -1;
 }
 
+int read_ref(const char *ref, unsigned char *sha1)
+{
+	return read_ref_full(ref, sha1, 1, NULL);
+}
+
 #define DO_FOR_EACH_INCLUDE_BROKEN 01
 static int do_one_ref(const char *base, each_ref_fn fn, int trim,
 		      int flags, void *cb_data, struct ref_entry *entry)
@@ -663,7 +668,7 @@ int peel_ref(const char *ref, unsigned char *sha1)
 		goto fallback;
 	}
 
-	if (!resolve_ref(ref, base, 1, &flag))
+	if (read_ref_full(ref, base, 1, &flag))
 		return -1;
 
 	if ((flag & REF_ISPACKED)) {
@@ -746,7 +751,7 @@ static int do_head_ref(const char *submodule, each_ref_fn fn, void *cb_data)
 		return 0;
 	}
 
-	if (resolve_ref("HEAD", sha1, 1, &flag))
+	if (!read_ref_full("HEAD", sha1, 1, &flag))
 		return fn("HEAD", sha1, flag, cb_data);
 
 	return 0;
@@ -826,7 +831,7 @@ int head_ref_namespaced(each_ref_fn fn, void *cb_data)
 	int flag;
 
 	strbuf_addf(&buf, "%sHEAD", get_git_namespace());
-	if (resolve_ref(buf.buf, sha1, 1, &flag))
+	if (!read_ref_full(buf.buf, sha1, 1, &flag))
 		ret = fn(buf.buf, sha1, flag, cb_data);
 	strbuf_release(&buf);
 
@@ -1022,7 +1027,7 @@ int refname_match(const char *abbrev_name, const char *full_name, const char **r
 static struct ref_lock *verify_lock(struct ref_lock *lock,
 	const unsigned char *old_sha1, int mustexist)
 {
-	if (!resolve_ref(lock->ref_name, lock->old_sha1, mustexist, NULL)) {
+	if (read_ref_full(lock->ref_name, lock->old_sha1, mustexist, NULL)) {
 		error("Can't verify ref %s", lock->ref_name);
 		unlock_ref(lock);
 		return NULL;
@@ -1377,7 +1382,8 @@ int rename_ref(const char *oldref, const char *newref, const char *logmsg)
 		goto rollback;
 	}
 
-	if (resolve_ref(newref, sha1, 1, &flag) && delete_ref(newref, sha1, REF_NODEREF)) {
+	if (!read_ref_full(newref, sha1, 1, &flag) &&
+	    delete_ref(newref, sha1, REF_NODEREF)) {
 		if (errno==EISDIR) {
 			if (remove_empty_directories(git_path("%s", newref))) {
 				error("Directory not empty: %s", newref);
@@ -1929,7 +1935,7 @@ static int do_for_each_reflog(const char *base, each_ref_fn fn, void *cb_data)
 				retval = do_for_each_reflog(log, fn, cb_data);
 			} else {
 				unsigned char sha1[20];
-				if (!resolve_ref(log, sha1, 0, NULL))
+				if (read_ref_full(log, sha1, 0, NULL))
 					retval = error("bad ref for %s", log);
 				else
 					retval = fn(log, sha1, 0, cb_data);
@@ -2072,7 +2078,6 @@ char *shorten_unambiguous_ref(const char *ref, int strict)
 		 */
 		for (j = 0; j < rules_to_fail; j++) {
 			const char *rule = ref_rev_parse_rules[j];
-			unsigned char short_objectname[20];
 			char refname[PATH_MAX];
 
 			/* skip matched rule */
@@ -2086,7 +2091,7 @@ char *shorten_unambiguous_ref(const char *ref, int strict)
 			 */
 			mksnpath(refname, sizeof(refname),
 				 rule, short_name_len, short_name);
-			if (!read_ref(refname, short_objectname))
+			if (ref_exists(refname))
 				break;
 		}