Re: [boost] [filesystem] file monitoring

Subject: Re: [boost] [filesystem] file monitoring
From: Boris (boriss_at_[hidden])
Date: 2008-10-23 09:21:03

On Thu, 23 Oct 2008 14:45:20 +0200, Carlos Rafael Giani  
<e0325834_at_[hidden]> wrote:

> is a file monitor feature planned for boost.filesystem? I have been  
> looking for a platform independent solution, but there is none (except  
> in toolkits like Qt). Also, so far only inotify (a subsystem in the  
> Linux kernel) can tell me when a file is closed after writing, which is  
> absolutely necessary when watching a plugins/ directory, for example  
> (you don't want to touch the plugins when they're only halfway copied).  
> Several tools watch the plugin directory, but don't care if the plugins  
> are being written or are fully there already. This can lead to  
> instabilities.
>
> I think it is only logical to add this to boost.filesystem, something  
> like set_monitor_callback(pathname, function_object);

I created a directory monitor as a Boost.Asio extension which is used like  
this:

boost::asio::io_service io_service;
boost::asio::dir_monitor dir_monitor(io_service);
dir_monitor.add_directory("C:\\Test");
boost::asio::dir_monitor_event ev = dir_monitor.monitor(); // or:  
dir_monitor.async_monitor(...)

While I finished the code I didn't have time yet to test it sufficiently.  
I hope I can put it online in the coming days.

While my directory monitor is Windows-only a Linux-only directory monitor  
is available since August - see  
http://article.gmane.org/gmane.comp.lib.boost.asio.user/2699. The  
Linux-only directory monitor is a bit unconventional though as for example  
it keeps firing events even if you call async_monitor only once. I'd like  
to see one platform-independent directory monitor in the future but would  
want to see my Windows-only directory monitor to become stable first.  
Anyway I'll post another message in a few days when I put the diretory  
monitor online.

Boris