[Qemu-devel] Re: ANN: QEMU Monitor Protocol git tree

[Avi Kivity]

On 09/23/2009 04:40 PM, Paolo Bonzini wrote:
> On 09/23/2009 12:57 PM, Avi Kivity wrote:
> > On 09/23/2009 12:57 PM, Daniel P. Berrange wrote:
> > > > Ignoring the dos-ism, since you can parse JSON with a regexp, why 
> > > > do we
> > > > need explicit message boundaries?
> > > I think it would be nice to be able to assume that each JSON message
> > > will not cross a line-end boundary. Whether we use CRLF, just CR or
> > > just LF I don't mind. Its much easier to search for a message boundary
> > > by just doing strchr('\n') than having to actually parse the JSON or
> > > use a regexp at that point.
> >
> > A good parser will consume exactly enough characters to make up an
> > object or let you know if it needs more. I don't think using a regexp is
> > warranted.
>
> Agreed, regexes are unnecessary.  Also because a regex cannot parse 
> JSON; it can only detect _some_ invalid JSON inputs, and then only if 
> you're given an already complete input.
>
> In other words, there are Javascript JSON parsers that are just "match 
> a regexp and run eval on the input", but the actual parsing is done by 
> the Javascript interpreter using eval.  The regexp is just avoiding 
> the security problems that are inherent in eval.

On the other hand, the two parsers I looked at only accept a string as 
input, not a stream (strangely, one of them internally converts the 
string to a stream, but doesn't expose the stream interface), so record 
termination might be helpful to parsers.  Would be best not to rely on 
it in the server, though.

--
error compiling committee.c: too many arguments to function