Re: [PATCH v2 05/12] checkout-index: simplify locking logic
Martin Ågren writes:
> `newfd` starts out negative. If we then take the lock, `newfd` will
> become non-negative. We later check for exactly that property before
> calling `write_locked_index()`. That is, we are simply using `newfd` as
> a boolean to keep track of whether we took the lock or not. (We always
> use `newfd` and `lock_file` together, so they really are mirroring each
> other.)
>
> Drop `newfd` and check with `is_lock_file_locked()` instead. While at
> it, move the `static struct lock_file` into `cmd_checkout_index()` and
> make it non-static. It is only used in this function, and after
> 076aa2cbd (tempfile: auto-allocate tempfiles on heap, 2017-09-05), we
> can have lockfiles on the stack.
>
> Signed-off-by: Martin Ågren
> ---
> v2: New patch.
Well reasoned and explained. Thanks.
>
> builtin/checkout-index.c | 8 +++-
> 1 file changed, 3 insertions(+), 5 deletions(-)
>
> diff --git a/builtin/checkout-index.c b/builtin/checkout-index.c
> index 39c8be05d..b0e78b819 100644
> --- a/builtin/checkout-index.c
> +++ b/builtin/checkout-index.c
> @@ -129,8 +129,6 @@ static const char * const builtin_checkout_index_usage[]
> = {
> NULL
> };
>
> -static struct lock_file lock_file;
> -
> static int option_parse_stage(const struct option *opt,
> const char *arg, int unset)
> {
> @@ -150,7 +148,7 @@ static int option_parse_stage(const struct option *opt,
> int cmd_checkout_index(int argc, const char **argv, const char *prefix)
> {
> int i;
> - int newfd = -1;
> + struct lock_file lock_file = LOCK_INIT;
> int all = 0;
> int read_from_stdin = 0;
> int prefix_length;
> @@ -206,7 +204,7 @@ int cmd_checkout_index(int argc, const char **argv, const
> char *prefix)
> if (index_opt && !state.base_dir_len && !to_tempfile) {
> state.refresh_cache = 1;
> state.istate = &the_index;
> - newfd = hold_locked_index(&lock_file, LOCK_DIE_ON_ERROR);
> + hold_locked_index(&lock_file, LOCK_DIE_ON_ERROR);
> }
>
> /* Check out named files first */
> @@ -251,7 +249,7 @@ int cmd_checkout_index(int argc, const char **argv, const
> char *prefix)
> if (all)
> checkout_all(prefix, prefix_length);
>
> - if (0 <= newfd &&
> + if (is_lock_file_locked(&lock_file) &&
> write_locked_index(&the_index, &lock_file, COMMIT_LOCK))
> die("Unable to write new index file");
> return 0;
[PATCH v2 05/12] checkout-index: simplify locking logic
`newfd` starts out negative. If we then take the lock, `newfd` will
become non-negative. We later check for exactly that property before
calling `write_locked_index()`. That is, we are simply using `newfd` as
a boolean to keep track of whether we took the lock or not. (We always
use `newfd` and `lock_file` together, so they really are mirroring each
other.)
Drop `newfd` and check with `is_lock_file_locked()` instead. While at
it, move the `static struct lock_file` into `cmd_checkout_index()` and
make it non-static. It is only used in this function, and after
076aa2cbd (tempfile: auto-allocate tempfiles on heap, 2017-09-05), we
can have lockfiles on the stack.
Signed-off-by: Martin Ågren
---
v2: New patch.
builtin/checkout-index.c | 8 +++-
1 file changed, 3 insertions(+), 5 deletions(-)
diff --git a/builtin/checkout-index.c b/builtin/checkout-index.c
index 39c8be05d..b0e78b819 100644
--- a/builtin/checkout-index.c
+++ b/builtin/checkout-index.c
@@ -129,8 +129,6 @@ static const char * const builtin_checkout_index_usage[] = {
NULL
};
-static struct lock_file lock_file;
-
static int option_parse_stage(const struct option *opt,
const char *arg, int unset)
{
@@ -150,7 +148,7 @@ static int option_parse_stage(const struct option *opt,
int cmd_checkout_index(int argc, const char **argv, const char *prefix)
{
int i;
- int newfd = -1;
+ struct lock_file lock_file = LOCK_INIT;
int all = 0;
int read_from_stdin = 0;
int prefix_length;
@@ -206,7 +204,7 @@ int cmd_checkout_index(int argc, const char **argv, const
char *prefix)
if (index_opt && !state.base_dir_len && !to_tempfile) {
state.refresh_cache = 1;
state.istate = &the_index;
- newfd = hold_locked_index(&lock_file, LOCK_DIE_ON_ERROR);
+ hold_locked_index(&lock_file, LOCK_DIE_ON_ERROR);
}
/* Check out named files first */
@@ -251,7 +249,7 @@ int cmd_checkout_index(int argc, const char **argv, const
char *prefix)
if (all)
checkout_all(prefix, prefix_length);
- if (0 <= newfd &&
+ if (is_lock_file_locked(&lock_file) &&
write_locked_index(&the_index, &lock_file, COMMIT_LOCK))
die("Unable to write new index file");
return 0;
--
2.14.2.666.gea220ee40
