Re: [PATCH v4 2/4] maintenance: introduce ENABLE/DISABLE for code clarity

[Phillip Wood <phillip.wood123@xxxxxxxxx>]

Hi Lénaïc

On 24/05/2021 08:15, Lénaïc Huard wrote:
> The first parameter of `XXX_update_schedule` and alike functions is a
> boolean specifying if the tasks should be scheduled or unscheduled.
>
> Using an `enum` with `ENABLE` and `DISABLE` values can make the code
> clearer.

I'm sorry to say that I'm not sure this does make the code clearer 
overall - I wish I'd spoken up when Danh suggested it.
While
	launchctl_boot_plist(DISABLE, filename, cmd)
is arguably clearer than
	launchctl_boot_plist(0, filename, cmd)
we end up with bizarre tests like
 	if (enabled == ENABLED)
rather than
	if (enabled)
and in the next patch we have
	(enable == ENABLE && (opts->scheduler == i)) ?
			ENABLE : DISABLE;
rather than
	enable && opts->scheduler == i

Also looking at the next patch it seems as this one is missing some 
conversions in maintenance_start() as it is still calling 
update_background_schedule() with an integer rather than the new enum.

I'd be happy to see this being dropped I'm afraid

Best Wishes

Phillip

> Signed-off-by: Lénaïc Huard <lenaic@xxxxxxxxx>
> ---
>   builtin/gc.c | 49 +++++++++++++++++++++++++++++++------------------
>   1 file changed, 31 insertions(+), 18 deletions(-)
>
> diff --git a/builtin/gc.c b/builtin/gc.c
> index ef7226d7bc..0caf8d45c4 100644
> --- a/builtin/gc.c
> +++ b/builtin/gc.c
> @@ -1570,19 +1570,21 @@ static char *launchctl_get_uid(void)
>   	return xstrfmt("gui/%d", getuid());
>   }
>   
> -static int launchctl_boot_plist(int enable, const char *filename, const char *cmd)
> +enum enable_or_disable {
> +	DISABLE,
> +	ENABLE
> +};
> +
> +static int launchctl_boot_plist(enum enable_or_disable enable,
> +				const char *filename, const char *cmd)
>   {
>   	int result;
>   	struct child_process child = CHILD_PROCESS_INIT;
>   	char *uid = launchctl_get_uid();
>   
>   	strvec_split(&child.args, cmd);
> -	if (enable)
> -		strvec_push(&child.args, "bootstrap");
> -	else
> -		strvec_push(&child.args, "bootout");
> -	strvec_push(&child.args, uid);
> -	strvec_push(&child.args, filename);
> +	strvec_pushl(&child.args, enable == ENABLE ? "bootstrap" : "bootout",
> +		     uid, filename, NULL);
>   
>   	child.no_stderr = 1;
>   	child.no_stdout = 1;
> @@ -1601,7 +1603,7 @@ static int launchctl_remove_plist(enum schedule_priority schedule, const char *c
>   	const char *frequency = get_frequency(schedule);
>   	char *name = launchctl_service_name(frequency);
>   	char *filename = launchctl_service_filename(name);
> -	int result = launchctl_boot_plist(0, filename, cmd);
> +	int result = launchctl_boot_plist(DISABLE, filename, cmd);
>   	unlink(filename);
>   	free(filename);
>   	free(name);
> @@ -1684,8 +1686,8 @@ static int launchctl_schedule_plist(const char *exec_path, enum schedule_priorit
>   	fclose(plist);
>   
>   	/* bootout might fail if not already running, so ignore */
> -	launchctl_boot_plist(0, filename, cmd);
> -	if (launchctl_boot_plist(1, filename, cmd))
> +	launchctl_boot_plist(DISABLE, filename, cmd);
> +	if (launchctl_boot_plist(ENABLE, filename, cmd))
>   		die(_("failed to bootstrap service %s"), filename);
>   
>   	free(filename);
> @@ -1702,12 +1704,17 @@ static int launchctl_add_plists(const char *cmd)
>   		launchctl_schedule_plist(exec_path, SCHEDULE_WEEKLY, cmd);
>   }
>   
> -static int launchctl_update_schedule(int run_maintenance, int fd, const char *cmd)
> +static int launchctl_update_schedule(enum enable_or_disable run_maintenance,
> +				     int fd, const char *cmd)
>   {
> -	if (run_maintenance)
> +	switch (run_maintenance) {
> +	case ENABLE:
>   		return launchctl_add_plists(cmd);
> -	else
> +	case DISABLE:
>   		return launchctl_remove_plists(cmd);
> +	default:
> +		BUG("invalid enable_or_disable value");
> +	}
>   }
>   
>   static char *schtasks_task_name(const char *frequency)
> @@ -1864,18 +1871,24 @@ static int schtasks_schedule_tasks(const char *cmd)
>   		schtasks_schedule_task(exec_path, SCHEDULE_WEEKLY, cmd);
>   }
>   
> -static int schtasks_update_schedule(int run_maintenance, int fd, const char *cmd)
> +static int schtasks_update_schedule(enum enable_or_disable run_maintenance,
> +				    int fd, const char *cmd)
>   {
> -	if (run_maintenance)
> +	switch (run_maintenance) {
> +	case ENABLE:
>   		return schtasks_schedule_tasks(cmd);
> -	else
> +	case DISABLE:
>   		return schtasks_remove_tasks(cmd);
> +	default:
> +		BUG("invalid enable_or_disable value");
> +	}
>   }
>   
>   #define BEGIN_LINE "# BEGIN GIT MAINTENANCE SCHEDULE"
>   #define END_LINE "# END GIT MAINTENANCE SCHEDULE"
>   
> -static int crontab_update_schedule(int run_maintenance, int fd, const char *cmd)
> +static int crontab_update_schedule(enum enable_or_disable run_maintenance,
> +				   int fd, const char *cmd)
>   {
>   	int result = 0;
>   	int in_old_region = 0;
> @@ -1925,7 +1938,7 @@ static int crontab_update_schedule(int run_maintenance, int fd, const char *cmd)
>   			fprintf(cron_in, "%s\n", line.buf);
>   	}
>   
> -	if (run_maintenance) {
> +	if (run_maintenance == ENABLE) {
>   		struct strbuf line_format = STRBUF_INIT;
>   		const char *exec_path = git_exec_path();
>