Re: [PATCH] libxl: new xlu_disk_parse function

From: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
To: Ian Jackson <Ian.Jackson@eu.citrix.com>
Cc: "xen-devel@lists.xensource.com" <xen-devel@lists.xensource.com>,
	Gianni Tedesco <gianni.tedesco@citrix.com>
Subject: Re: [PATCH] libxl: new xlu_disk_parse function
Date: Mon, 4 Apr 2011 12:29:40 +0100	[thread overview]
Message-ID: <alpine.DEB.2.00.1104041225370.16492@kaball-desktop> (raw)
In-Reply-To: <19860.47659.19132.816771@mariner.uk.xensource.com>

On Thu, 31 Mar 2011, Ian Jackson wrote:
> > > +raw:           { DSET(format,FORMAT,RAW); }
> > > +qcow:          { DSET(format,FORMAT,QCOW); }
> > > +qcow2:         { DSET(format,FORMAT,QCOW2); }
> > > +vhd:           { DSET(format,FORMAT,QCOW2); }
> > > +
> > > +phy:           { DSET(format,FORMAT,RAW); DSET(backend,BACKEND,PHY); }
> > > +file:          { DSET(format,FORMAT,RAW); DSET(backend,BACKEND,TAP); }
> > > +tapdisk:|tap2?:        { DSET(backend,BACKEND,TAP); }
> > > +aio:           { }
> > > +ioemu:         { }
> > 
> > This bit is quite nice though. We could probably just tidy up the
> > existing parser using arrays of values and things rather than a lot of
> > if/else statements though.
> 
> I wanted to avoid parsing with pointer arithmetic, which is very easy
> to write bugs in - particularly when new features are added.

We'll just have to be careful. I certainly find easier to read (and
therefore to debug and maintain) the current state machine than this
patch.