Re: [dpdk-dev] [PATCH v3 2/2] cmdline: make struct rdline opaque

[Olivier Matz <olivier.matz@6wind.com>]

On Tue, Oct 05, 2021 at 12:03:01PM +0300, Dmitry Kozlyuk wrote:
> Hi Olivier,
> 
> Thanks for the review, please see below.
> 
> 2021-10-05 10:27 (UTC+0200), Olivier Matz:
> > [...]
> > > diff --git a/lib/cmdline/cmdline_cirbuf.c b/lib/cmdline/cmdline_cirbuf.c
> > > index 829a8af563..cbb76a7016 100644
> > > --- a/lib/cmdline/cmdline_cirbuf.c
> > > +++ b/lib/cmdline/cmdline_cirbuf.c
> > > @@ -10,7 +10,6 @@
> > >  
> > >  #include "cmdline_cirbuf.h"
> > >  
> > > -
> > >  int
> > >  cirbuf_init(struct cirbuf *cbuf, char *buf, unsigned int start, unsigned int maxlen)
> > >  {  
> > 
> > unexpected change
> 
> Will remove in v4.
> 
> > [...]
> > 
> > > --- a/lib/cmdline/cmdline_rdline.c
> > > +++ b/lib/cmdline/cmdline_rdline.c
> > > @@ -13,6 +13,7 @@
> > >  #include <ctype.h>
> > >  
> > >  #include "cmdline_cirbuf.h"
> > > +#include "cmdline_private.h"
> > >  #include "cmdline_rdline.h"
> > >  
> > >  static void rdline_puts(struct rdline *rdl, const char *buf);
> > > @@ -37,9 +38,10 @@ isblank2(char c)
> > >  
> > >  int
> > >  rdline_init(struct rdline *rdl,
> > > -		 rdline_write_char_t *write_char,
> > > -		 rdline_validate_t *validate,
> > > -		 rdline_complete_t *complete)
> > > +	    rdline_write_char_t *write_char,
> > > +	    rdline_validate_t *validate,
> > > +	    rdline_complete_t *complete,
> > > +	    void *opaque)
> > >  {
> > >  	if (!rdl || !write_char || !validate || !complete)
> > >  		return -EINVAL;
> > > @@ -47,10 +49,40 @@ rdline_init(struct rdline *rdl,
> > >  	rdl->validate = validate;
> > >  	rdl->complete = complete;
> > >  	rdl->write_char = write_char;
> > > +	rdl->opaque = opaque;
> > >  	rdl->status = RDLINE_INIT;
> > >  	return cirbuf_init(&rdl->history, rdl->history_buf, 0, RDLINE_HISTORY_BUF_SIZE);
> > >  }
> > >  
> > > +int
> > > +rdline_create(struct rdline **out,
> > > +	      rdline_write_char_t *write_char,
> > > +	      rdline_validate_t *validate,
> > > +	      rdline_complete_t *complete,
> > > +	      void *opaque)
> > > +{  
> > 
> > For consistency, wouldn't it be better to keep the same model than
> > cmdline_new()? I mean return a pointer and name it rdline_new().
> 
> If we don't really need to distinguish EINVAL and ENOMEM errors here,
> then I agree. Otherwise, do you propose to return the error code via
> rte_errno? Currenly no cmdline functions use it. This would also add a
> runtime dependency on EAL (currently cmdline only depends on its headers).

Good point, I was indeed thinking about NULL + rte_errno, but I did not
anticipate the new dependency to eal.

Given there's no errno in cmdline_new(), which is the main user API, I think
we can do the same for rdline_new().


> > [...]
> > > +size_t
> > > +rdline_get_history_buffer_size(struct rdline *rdl)
> > > +{
> > > +	return sizeof(rdl->history_buf);
> > > +}
> > > +
> > > +void *
> > > +rdline_get_opaque(struct rdline *rdl)
> > > +{
> > > +	return rdl != NULL ? rdl->opaque : NULL;
> > > +}  
> > 
> > rdline_get_opaque() is safe when rdl is NULL, but
> > rdline_get_history_buffer_size() is not.
> > 
> > To me, both are acceptable but I'd prefer to have the same behavior
> > for these 2 functions.
> 
> rdline_get_history_buffer_size() is safe because sizeof() is evaluated at
> compile time. There's a unit test checking that all functions are NULL-safe.

Oh yes, of course, thanks.