Thanks Ken, On Jan 29, 2011, at 10:36 AM, Robert DuToit wrote:
> Thanks Ken, > On Jan 29, 2011, at 9:29 AM, Ken Thomases wrote: > >> On Jan 29, 2011, at 8:01 AM, Robert DuToit wrote: >> >>> On Jan 29, 2011, at 5:15 AM, Ken Thomases wrote: >>> >>>> You should definitely not be creating subprocesses to run 'tail' or 'ps'. >>>> 'tail' is just a file reader, and your app can directly open and read the >>>> file. To monitor whether rsync is still running, you may be able to use >>>> the techniques illustrated in these articles: >>> >>> I know - I didn't see any easy way to directly read in just some last lines >>> of the log as 'tail' does assuming you don't want to read in 1 million >>> lines of a log every fraction of a second and then parse. I'll research >>> this more. >> >> You shouldn't open the file and read from the beginning every time. Open >> the file once after rsync creates it, then read some data (perhaps up to the >> then-current end of file) and parse it, keeping in mind that the final line >> may be incomplete. At the next firing of your timer, clear the end-of-file >> marker and read some more. Append the new data to whatever partial line was >> left over from the last time. Etc. > I have been googling around and not sure how to do this - is it with NSData or NSStream perhaps? Cheers and thanks for all, Rob > I have been googling around and not sure how to do this - is it with NSData > or NSStream perhaps? > > Cheers and thanks for all, > > Rob > > >> >> >>>> It may also be possible to use a pipe to the rsync process not for >>>> communicating its output but just to monitor its lifetime. If you >>>> redirect most of rsync's output to a file (e.g. using the --log-file >>>> option), then you can monitor its stdout (and/or stderr) from your app. >>>> When it closes, the process has presumably exited. >>> >>> I hadn't thought of that - I was redirecting the stdout in the Helper Tool >>> using a timer to poll the log but never thought of the rsync option itself! >>> I'll have to check this out. That would do away with the ps call nicely. >>> Isn't the stdout already redirected to the file though via rsync? Maybe the >>> two can coincide. >> >> I wouldn't expect the --log-file option to redirect stdout. Even if it did, >> you can (and probably should) capture the rsync stderr via the pipe, and >> that should only close when the process exits. >> >>> Thanks Ken. This has been an enlightening discussion. >> >> You're welcome. >> >> Cheers, >> Ken >> > _______________________________________________ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
