On 12/31/2016 07:32 AM, Jeff King wrote: > On Sat, Dec 31, 2016 at 04:12:53AM +0100, Michael Haggerty wrote: > >> This function will most often be called by log_ref_write_1(), which >> wants to append to the reflog file. In that case, it is silly to close >> the file only for the caller to reopen it immediately. So, in the case >> that the file was opened, pass the open file descriptor back to the >> caller. > > Sounds like a much saner interface. > >> /* >> - * Create a reflog for a ref. If force_create = 0, the reflog will >> - * only be created for certain refs (those for which >> - * should_autocreate_reflog returns non-zero. Otherwise, create it >> - * regardless of the ref name. Fill in *err and return -1 on failure. >> + * Create a reflog for a ref. Store its path to *logfile. If >> + * force_create = 0, only create the reflog for certain refs (those >> + * for which should_autocreate_reflog returns non-zero). Otherwise, >> + * create it regardless of the reference name. If the logfile already >> + * existed or was created, return 0 and set *logfd to the file >> + * descriptor opened for appending to the file. If no logfile exists >> + * and we decided not to create one, return 0 and set *logfd to -1. On >> + * failure, fill in *err, set *logfd to -1, and return -1. >> */ >> -static int log_ref_setup(const char *refname, struct strbuf *logfile, struct strbuf *err, int force_create) >> +static int log_ref_setup(const char *refname, >> + struct strbuf *logfile, int *logfd, >> + struct strbuf *err, int force_create) > > The return value is always "0" or "-1". It seems like it would be > simpler to just return the descriptor instead of 0. > > I guess that makes it hard to identify the case when we chose not to > create a descriptor. I wonder if more "normal" semantics would be: > > 1. ret >= 0: file existed or was created, and ret is the descriptor > > 2. ret < 0, err is empty: we chose not to create > > 3. ret < 0, err is non-empty: a real error I don't like making callers read err to find out whether the call was successful, and I think we've been able to avoid that pattern so far. Another alternative would be to make ret == -1 mean a real error and ret == -2 mean that we chose not to create the file. But that would be straying from the usual "-1 means error" interface of open(), so I wasn't fond of that idea either. > I dunno. This may just be bikeshedding, and I can live with it either > way (especially because you documented it!). Let's see if anybody has a strong opinion about it; otherwise I'd rather leave it as is. Michael