try_merge_strategy(): use a statically-allocated lock_file object

Even the one lockfile object needn't be allocated each time the
function is called.  Instead, define one statically-allocated
lock_file object and reuse it for every call.

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

diff --git a/builtin/merge.c b/builtin/merge.c
index 1ec39394af3a9db0b21338a8cb31d95ea3d48daa..be07f27487bf839444f8e2a6c1af117bad42a0e5 100644 (file)
--- a/builtin/merge.c
+++ b/builtin/merge.c
@@ -656,14 +656,14 @@ static int try_merge_strategy(const char *strategy, struct commit_list *common,
                              struct commit_list *remoteheads,
                              struct commit *head, const char *head_arg)
 {
-       struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
+       static struct lock_file lock;
 
-       hold_locked_index(lock, 1);
+       hold_locked_index(&lock, 1);
        refresh_cache(REFRESH_QUIET);
        if (active_cache_changed &&
-           write_locked_index(&the_index, lock, COMMIT_LOCK))
+           write_locked_index(&the_index, &lock, COMMIT_LOCK))
                return error(_("Unable to write index."));
-       rollback_lock_file(lock);
+       rollback_lock_file(&lock);
 
        if (!strcmp(strategy, "recursive") || !strcmp(strategy, "subtree")) {
                int clean, x;
@@ -695,13 +695,13 @@ static int try_merge_strategy(const char *strategy, struct commit_list *common,
                for (j = common; j; j = j->next)
                        commit_list_insert(j->item, &reversed);
 
-               hold_locked_index(lock, 1);
+               hold_locked_index(&lock, 1);
                clean = merge_recursive(&o, head,
                                remoteheads->item, reversed, &result);
                if (active_cache_changed &&
-                   write_locked_index(&the_index, lock, COMMIT_LOCK))
+                   write_locked_index(&the_index, &lock, COMMIT_LOCK))
                        die (_("unable to write %s"), get_index_file());
-               rollback_lock_file(lock);
+               rollback_lock_file(&lock);
                return clean ? 0 : 1;
        } else {
                return try_merge_command(strategy, xopts_nr, xopts,