[ naviserver-Feature Requests-1202462 ] Rewrite to use Tcl VFS filesystem abstraction

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Feature Requests item #1202462, was opened at 2005-05-15 22:14
Message generated for change (Comment added) made by vasiljevic
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Category: C-API
Group: None
Status: Open
Resolution: None
Priority: 5
Submitted By: Zoran Vasiljevic (vasiljevic)
Assigned to: Zoran Vasiljevic (vasiljevic)
Summary: Rewrite to use Tcl VFS filesystem abstraction

Initial Comment:
We should really invest some time and rewrite all
(most?) of the
internal usages of open(), stat() (etc) so we can take
advantage of
Tcl virtual filesystem wappers. 


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>Comment By: Zoran Vasiljevic (vasiljevic)
Date: 2005-05-16 13:43

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Oh yes. The packaging is what I'm (mostly) after. 

The only parts where mmap is used is fastpath.c.
I do not know what/where is sendfile...

So, effectively, the mmap has to be *enabled* to be
used, right? Well, there is nothing wrong in leaving the
mmap inplace. Actually, it should be also done in the 
way that Windows platform can use it (nees some wrapping
but its easy done). 

But, it mmap is not enabled? Then the server uses standard
open/read/close stuff from the OS. Now, what's wrong  in
using Tcl API equivalents of that? In that case, it is transparent
where the file actually comes from, filesystem, zip/tarfile, etc...
Do you think this could hit us performance-wise. I do not know.
Maybe, but it's worth trying it out.  

Also, there are whole lotta places where the server uses OS
calls to the filesystem which has nothing to do with serving
pages (logfiles, access files, config files, etc...). These are 
not sensitive performance-wise and those places should/could
be rewritten so we can bootstrap from zipfile if needed.
Or be entirely wrapped in a startkit.

What do you think?

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Comment By: Stephen Deasey (sdeasey)
Date: 2005-05-16 13:30

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I'd be reluctant to let go of mmap and sendfile, considering
our niche as a performace server.

You can already use the vfs to read zip files etc., it's the
single file packaging your after, right?


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Comment By: Zoran Vasiljevic (vasiljevic)
Date: 2005-05-16 08:55

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The advantage is that you can for example, assemble all of the server
distro in a starkit and distribute it as a wrapped application.
Also, all sorts of filesystem wrappers (tar, zip, metakit, http, ...)
are already implemeted in TclVFS so you can serve pages out of 
the tar/zip files directly, for example.

No, mmap kind of things would be not possible since all would be 
going thru Tcl API. But, where is the mmap used? I believe only 
in fastpath and only if you explicitly enable it. And, only for Unix
port. 





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Comment By: Stephen Deasey (sdeasey)
Date: 2005-05-16 01:25

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What would be the advantage of using the Tcl VFS?  Would it
be just as fast?  Could we still use performance enhancemts
such as mmap() and sendfile()?


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