Re: OSX FSEvents file watching support

[Muir Manders]

> FSEvents only reports the directory where changes occurred.

Based on my testing, FSEvents reports the full file path for each change along 
with metadata about the file and the change.

Here is the test program I was using to play around with it: 
https://gist.github.com/muirrn/ea8c63c22ca7624f304f805ba77b25f4

Muir

On Thu, Jul 18, 2019, at 2:54 AM, Mattias Engdegård wrote:
> 17 juli 2019 kl. 06.18 skrev Muir Manders <address@hidden>:
> > 
> > I am interested in adding support in Emacs for Mac OS "FSEvents" file 
> > watching. FSEvents allows for efficient recursive directory watching, which 
> > would be a boon for packages like lsp-mode.
> 
> Good!
> 
> > 1. Write a new backend for filenotify.el. The existing backends explicitly 
> > don't support recursive watching, so I'm not sure if it makes sense to have 
> > one special backend that does support recursive watching.
> 
> This is probably the way to go, but some careful interface design is 
> necessary. For example, FSEvents only reports the directory where 
> changes occurred. For some applications this may be sufficient, but for 
> others, the exact file names are required. What about lsp-mode? Without 
> a specific application in mind, we risk over-engineering.
> 
> FSEvents can probably co-exist with kqueue which fits the filenotify 
> model better for watching individual files, but it would be nice to 
> have something that scales better (kqueue uses up file descriptors). On 
> the other hand, FSEvents may require careful filtering to avoid being 
> swamped with notifications during periods of intensive file system 
> change.
> 
>