From gambas at ...1...  Thu Jan 23 03:34:51 2014
From: gambas at ...1... (=?ISO-8859-1?Q?Beno=EEt_Minisini?=)
Date: Thu, 23 Jan 2014 03:34:51 +0100
Subject: [Gambas-devel] About gb.inotify
Message-ID: <52E07FCB.3080509@...1...>

Hi,

Here is a few remarks about gb.inotify, wrote as I read your code. So I 
may say rubbish. :-)

1) inotify is a Linux kernel specific thing. So I strongly suggest 
finding a generic name for the class and the component. "PathWatch", or 
just "Watch". If you find better, you're welcome!

2) Don't do:

	path = GB.NewZeroString(GB.ToZeroString(ARG(path)));

Do instead:

	path = GB.NewString(STRING(path), LENGTH(path));

One useless string copy avoided.

3) You can use GB.CanRaise() to know which event is handled by a new 
object. Consequently, you will be able to define the inotify_add_watch() 
mask automatically if the user does not specify it. No need to watch 
everything by default!

4) I don't think the ".InotifyEvents" class with one property for each 
event flag is really useful. As soon as you defined constants in the 
Inotify class for each event, you can define a Inotify.Events property 
as a pseudo-array of booleans:

	Inotify.Events[Inotify.Access] = True

Or you can use methods :

	Inotify.Add(INotify.Access + INotify.Attribute)
	Inotify.Remove(...)

5) The harder : portability! The inotify equivalent of other systems are 
usually not as powerful.

You should look at something like 
http://pnotify.googlecode.com/svn/trunk/README to get an idea of what 
not to implement in the hope of being portable. Maybe you can include 
that library in your component if it is good. I didn't really look at it 
: it is not maintained anymore.

For a better alternative, you have to look at 
http://www.heily.com/~mheily/proj/libkqueue/ instead, and 
http://people.freebsd.org/~jlemon/papers/kqueue.pdf

I just noted that kqueue watch file by file descriptor, which may be 
annoying. But it can associate a user pointer to any event, so no need 
to scan a linked list of Gambas objects!

If it is too difficult for you, just keep gb.inotify and fix the 
previous points.

Enough for now, let's go to bed!

Regards,

-- 
Beno?t Minisini