This will be used to implement IMAP IDLE, first.
Eventually, it may be used to trigger other things:
* incremental internal updates for manifest.js.gz
* restart `git cat-file' processes on pack index unlink
* IMAP IDLE-like long-polling HTTP endpoint
And maybe more things we haven't thought of, yet.
It uses Linux::Inotify2 or IO::KQueue depending on what packages
are installed and what the kernel supports. It falls back to
nanosecond-aware Time::HiRes::stat() (available with Perl 5.10.0+)
on systems lacking Linux::Inotify2 and IO::KQueue.
In the future, a pure Perl alternative to Linux::Inotify2 may be
supplied for users of architectures we already support signalfd
and epoll on.
v2 changes:
- avoid O_TRUNC on lock file
- change ctime on Linux systems w/o inotify
- fix naming of comments and fields