After reviewing this proposal again I'm still worried about direct multi-user usage. Locking single files seems doable, but I see problems e.g. when you move a file and want to update links in X other files. Would you need to lock all these files before proceeding ? If so, lot of code needs to be touched.
Easier option is a single lock per notebook, but that essentially enforces a single editor at a time, so not multi-user at all. -- Jaap On Thu, Mar 1, 2012 at 8:36 PM, Jaap Karssenberg <jaap.karssenb...@gmail.com> wrote: > On Thu, Mar 1, 2012 at 8:18 PM, João Santos <j...@jsantos.eu> wrote: >> >> Apparently renaming a directory is atomic on windows if you can guaranty >> that the destination name doesn't exist, so I think we can use that to >> ensure that the lock is removed atomically, if we use the an uuid based name >> as the destination name, and removing it after that. > > > Agreed, so to summarize: > > When creating a lock, we need to create the directory first under another > name, and then rename it to the lock directory. If someone tries to do the > same at the same time, one of both should fail because the lock already > exists. > > For remove we need to do the opposite, move it to another name, than delete > it. > > Creating a folder, than the file, or first deleting the file, than the > folder, could leave an empty folder if we crash in between the two actions. > > Becomes quite involved, so think we need to hide this from the user, > probably I will put the locks in a ".locks" folder in the notebook folder to > keep them out of sight. > > Maybe when zim initializes, we should do a cleanup of empty folders than are > older than X minutes (so crashes get cleaned up). > > Also I would say re-touch the lockfile every few minutes, so if we want to > acquire a lock, and the file is older than X hours, we just break it without > bothering the user. > > Regards, > > Jaap > _______________________________________________ Mailing list: https://launchpad.net/~zim-wiki Post to : zim-wiki@lists.launchpad.net Unsubscribe : https://launchpad.net/~zim-wiki More help : https://help.launchpad.net/ListHelp
