Re: [PATCH] Fix handle leak in write_tree

On 4/24/07, Junio C Hamano [off-list ref] wrote:

quoted

How about something like this (just interface):

struct lock_file
{
      struct lock_file *next;
      pid_t owner;
      int fd;
      char on_list;
      char filename[PATH_MAX];
};

struct lock_file *open_locked(const char *path, int die_on_error);
struct lock_file *open_index_locked(int die_on_error);
void commit_lock_file(struct lock_file *); /* always assuming .lock */
void rollback_lock_file(struct lock_file *);

I agree that making commit and rollback close the file
descriptor and lock holders to use lock->fd for write() makes
more sense, although it is a bit unclear from the above set of
function signatures what your plan on the lifetime rule for
"struct lock_file" is.  If it will be linked to the list given
to the atexit() handler and the caller of open_locked() never
frees it, I think I am fine with the interface.

I actually expected the caller to define the lifetime. atexit is not exactly
libification-effort friendly. I could imagine open*locked with an additional
argument for atexit registration, I just don't like the idea (dislike
die_on_error
too). Isn't such kind of resource control _generally_ nicer to implement
in the top levels of a program?