write_ref_sha1(): move write elision test to callers

write_ref_sha1() previously skipped the write if the reference already
had the desired value, unless lock->force_write was set. Instead,
perform that test at the callers.

Two of the callers (in rename_ref()) unconditionally set force_write
just before calling write_ref_sha1(), so they don't need the extra
check at all. Nor do they need to set force_write anymore.

The last caller, in ref_transaction_commit(), still needs the test.

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

diff --git a/refs.c b/refs.c
index d1130e2259689ae891990cfb8450a2de77134ca8..651e37e127dd4cc2d93772678c74a8a5304c3049 100644 (file)
--- a/refs.c
+++ b/refs.c
@@ -2878,7 +2878,6 @@ int rename_ref(const char *oldrefname, const char *newrefname, const char *logms
                error("unable to lock %s for update", newrefname);
                goto rollback;
        }
-       lock->force_write = 1;
        hashcpy(lock->old_sha1, orig_sha1);
        if (write_ref_sha1(lock, orig_sha1, logmsg)) {
                error("unable to write current sha1 into %s", newrefname);
@@ -2894,7 +2893,6 @@ int rename_ref(const char *oldrefname, const char *newrefname, const char *logms
                goto rollbacklog;
        }
 
-       lock->force_write = 1;
        flag = log_all_ref_updates;
        log_all_ref_updates = 0;
        if (write_ref_sha1(lock, orig_sha1, NULL))
@@ -3080,10 +3078,6 @@ static int write_ref_sha1(struct ref_lock *lock,
        static char term = '\n';
        struct object *o;
 
-       if (!lock->force_write && !hashcmp(lock->old_sha1, sha1)) {
-               unlock_ref(lock);
-               return 0;
-       }
        o = parse_object(sha1);
        if (!o) {
                error("Trying to write ref %s with nonexistent object %s",
@@ -3797,15 +3791,21 @@ int ref_transaction_commit(struct ref_transaction *transaction,
                struct ref_update *update = updates[i];
 
                if (!is_null_sha1(update->new_sha1)) {
-                       if (write_ref_sha1(update->lock, update->new_sha1,
-                                          update->msg)) {
+                       if (!update->lock->force_write &&
+                           !hashcmp(update->lock->old_sha1, update->new_sha1)) {
+                               unlock_ref(update->lock);
+                               update->lock = NULL;
+                       } else if (write_ref_sha1(update->lock, update->new_sha1,
+                                                 update->msg)) {
                                update->lock = NULL; /* freed by write_ref_sha1 */
                                strbuf_addf(err, "Cannot update the ref '%s'.",
                                            update->refname);
                                ret = TRANSACTION_GENERIC_ERROR;
                                goto cleanup;
+                       } else {
+                               /* freed by write_ref_sha1(): */
+                               update->lock = NULL;
                        }
-                       update->lock = NULL; /* freed by write_ref_sha1 */
                }
        }