[Qemu-devel] Re: [PATCH 2/6] json-lexer: Handle missing escapes

[Luiz Capitulino]

On Thu, 20 May 2010 11:55:00 -0500
Anthony Liguori <anth...@codemonkey.ws> wrote:

> On 05/20/2010 11:27 AM, Luiz Capitulino wrote:
> > On Thu, 20 May 2010 10:50:41 -0500
> > Anthony Liguori<anth...@codemonkey.ws>  wrote:
> >
> >    
> >> On 05/20/2010 10:16 AM, Paolo Bonzini wrote:
> >>      
> >>> On 05/20/2010 03:44 PM, Luiz Capitulino wrote:
> >>>        
> >>>>    I think there's another issue in the handling of strings.
> >>>>
> >>>>    The spec says that valid unescaped chars are in the following range:
> >>>>
> >>>>       unescaped = %x20-21 / %x23-5B / %x5D-10FFFF
> >>>>          
> >> That's a spec bug IMHO.  Tab is %x09.  Surely you can include tabs in
> >> strings.  Any parser that didn't accept that would be broken.
> >>      
> >   Honestly, I had the impression this should be encoded as: %x5C %x74, but
> > if you're right, wouldn't this be true for other sequences as well?
> >    
> 
> I don't think most reasonable clients are going to quote tabs as '\t'.

 That would be a bug, wouldn't it?

 Python example:

>>> json.dumps('\t')
'"\\t"'
>>>

 YAJL example (inlined below):

/tmp/ ./teste
0x22 0x5c 0x74 0x22
/tmp/ 

 I think we should strictly conform to the spec, quirks should only be
added when really needed.

#include <stdio.h>
#include <yajl/yajl_gen.h>

int main(void)
{
    yajl_gen g;
    unsigned int i, len = 0;
    const unsigned char *str = NULL;
    yajl_gen_config conf = { 0, " " };

    g = yajl_gen_alloc(&conf, NULL);

    if (yajl_gen_string(g, (unsigned char *) "\t", 1) != yajl_gen_status_ok)
        return 1;
    if (yajl_gen_get_buf(g, &str, &len) != yajl_gen_status_ok)
        return 1;

    for (i = 0; i < len; i++)
        printf("0x%x ", str[i]);
    printf("\n");

    return 0;
}