@matheusbsbs / matheus-bagliano / commits / 2954e5ec43

cache-tree: simplify locking logic

After we have taken the lock using `LOCK_DIE_ON_ERROR`, we know that `newfd` is non-negative. So when we check for exactly that property before calling `write_locked_index()`, the outcome is guaranteed. If we write and commit successfully, we set `newfd = -1`, so that we can later avoid calling `rollback_lock_file` on an already-committed lock. But we might just as well unconditionally call `rollback_lock_file()` -- it will be a no-op if we have already committed. All in all, we use `newfd` as a bool and the only benefit we get from it is that we can avoid calling a no-op. Remove `newfd` so that we have one variable less to reason about. Signed-off-by: Martin Ågren <martin.agren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Martin Ågren committed Oct 5, 2017 at 22:32 UTC 2954e5ec4361c6932593663859aa437583edb500

1 file changed +4 -8

cache-tree.c

+4 -8

@@ -602,11 +602,11 @@ static struct cache_tree *cache_tree_find(struct cache_tree *it, const char *pat

602

603 int write_index_as_tree(unsigned char *sha1, struct index_state *index_state, const char *index_path, int flags, const char *prefix)

604 {

605 - int entries, was_valid, newfd;

605 + int entries, was_valid;

606 struct lock_file lock_file = LOCK_INIT;

607 int ret = 0;

608

609 - newfd = hold_lock_file_for_update(&lock_file, index_path, LOCK_DIE_ON_ERROR);

609 + hold_lock_file_for_update(&lock_file, index_path, LOCK_DIE_ON_ERROR);

610

611 entries = read_index_from(index_state, index_path);

612 if (entries < 0) {

@@ -625,10 +625,7 @@ int write_index_as_tree(unsigned char *sha1, struct index_state *index_state, co

625 ret = WRITE_TREE_UNMERGED_INDEX;

626 goto out;

627 }

628 - if (0 <= newfd) {

629 - if (!write_locked_index(index_state, &lock_file, COMMIT_LOCK))

630 - newfd = -1;

631 - }

628 + write_locked_index(index_state, &lock_file, COMMIT_LOCK);

629 /* Not being able to write is fine -- we are only interested

630 * in updating the cache-tree part, and if the next caller

631 * ends up using the old index with unupdated cache-tree part

@@ -650,8 +647,7 @@ int write_index_as_tree(unsigned char *sha1, struct index_state *index_state, co

647 hashcpy(sha1, index_state->cache_tree->oid.hash);

648

649 out:

653 - if (0 <= newfd)

654 - rollback_lock_file(&lock_file);

650 + rollback_lock_file(&lock_file);

651 return ret;

652 }

653