Re: [lwip-devel] Cleaner include handling / using pbuf standalone

[address@hidden]

Am 08.02.10 15:50, schrieb Kieran Mansley:
> On Mon, 2010-02-08 at 09:39 -0500, Bill Auerbach wrote:
>    
> > I have 3 points on lwIP #includes I’d like to make and maybe see
> > improvements for:
> >
> > 1)      When I use other 3rd party libraries or code to include in a
> > project, I have rarely had to use anything but one search path in the
> > compiler options to have the compiler find all of the #include files.
> > With lwIP I find I have to add 3 or 4 search paths to the compiler
> > options.  It sure would be nice to have one, like “lwip/src/include”
> > and have that be all that’s required to find all of the files.
> >      
> This is largely down to the way lwIP is distributed in two parts: the
> core lwIP code and a system-dependent port.
Besides from the core/port issue there is the ipv4/v6 issue. This can 
currently only be solved by giving he headers different names (i.e. 
adding v4 or v6 to the names somewhere). Then there's the include/netif 
directory. This one could indeed be removed, I guess, since it only 
contains 3 files or so (note that the api headers are in the core 
include directory, too, so why not the netif headers).
> You get header files from
> the two halves.  Historically these have been kept in two separate
> places in the filing system for simplicity of porting I suppose.
> There's no reason why a port couldn't be done by putting all of its own
> code in with the lwIP tree and so cut down on the locations of header
> files, if you wanted to do things that way.
>    
That won't work currently, as cc.h and sys_arch.h are incuded as 
"arch/cc.h" and "arch/sys_arch.h".
> > 2)      I’m doing a new lwIP platform port and I want the low-level
> > hardware driver to be as standalone as possible.  The driver needs
> > only the struct pbuf declaration to be able to send and receive
> > packets.  So I added #include “pbuf.h”.  But it includes opts.h and
> > err.h.  pbuf.h only needs the type definitions.  It would be nice to
> > include only that file.  Doing this also shows point 1 above – I had
> > to add 4 search paths simply to include pbuf.h.
> >      
> Can you give examples of what the four search paths you needed were?
> opt.h and err.h should both be in the same location as pbuf.h
>    
At least for the current CVS code, the directories containing pbuf.h and 
cc.h should be enough, I think, since neither netif- nor ipv4-headers 
are included by pbuf.h.
> Splitting header files is usually a good idea so that code can just
> import the actual bits it needs, but you reach a practical limit where
> dependencies between header files get complex and cyclical.
Well, I do think there's some room for improvement in lwIP and I already 
improved a little. Especially tcp.h could be splitted into an external 
part (for applications) and an internal part (for the tcp 
implementation). Personally, I'm open to suggestions here.

Simon