Lookup Watch ID Given a Path?

[chrisdonlan]

Any intention to add a 4th method: get_wd(path)? This would be very useful for me to have implemented here (rather than around INotify in my code), and am willing to add this and PR if it is alright.

[letorbi]

Hej Chris,

I actually had get_wd(path) implemented in a development version that was never committed, but decided to remove it in the end, because - at least in my implementation - deriving wd from path was quite expensive, because in general for a path, which consists of n parts, the whole __info map has to be searched n times.

The are probably some optimization-possibilities for specials cases, but I didn't implement them, because I thought that even in the best case the __info map has to be searched one time. In general the fastest general solution I could think of would be to store wd in a path:wd map right after the add_watch_recursive() call, if you know that you need wd later. The worst case of this implementation would be still as fast as the best case of my get_wd(path) implementation, so I decdied to drop get_wd(path) again.

Apart from the speed considerations I also didn't like the idea of having a get_wd(path) function, because I'd like to follow the implement-only-the-necessary-philosophy of the underlying inotify_simple package. In fact I'd be happy, if I could drop get_path(wd) as well ;)

However, I'd like to know your implementation and the reasons why you need it. So please create a PR, if you have the code done already. Maybe my previous conclusions were wrong and it makes sense to include get_wd(path) into the package anyway.

[letorbi]

Hej Chris,

any news on this issue? I'm still curious about your implementation. If not, I would close this issue by the end of this week.