Re: [Qemu-devel] [PATCH] qemu: json: Fix parsing of integers >= 0x8000000000000000

[Anthony Liguori]

On 05/23/2011 10:29 AM, Richard W.M. Jones wrote:
> On Mon, May 23, 2011 at 10:24:07AM -0500, Anthony Liguori wrote:
> > On 05/23/2011 10:19 AM, Richard W.M. Jones wrote:
> > What I suggested would let us work with any JSON client, but if
> > clients loose precision after 53-bits, those clients would not work
> > well with QEMU.
>
> I totally agree that the JSON "standard" is completely underspecified
> and not very useful (lacking a schema, strong typing, well-specified
> limits).  Nevertheless, for better or worse it's what we're using.
>
> There is one very important JSON client we are using called libvirt.

No, libvirt is a virtualization library.  It happens to have a home 
grown JSON client but down the road, if there's a nice, common JSON 
library and it decides to switch to it, we don't want to have a bunch of 
compatibility issues that prevents that from happening.

The point of using a standard RPC is to support multiple clients. 
Otherwise, we should just stop calling it JSON and make it behave the 
way we want it to.

> > The alternative approach is to be conservative and only use 32-bit
> > integers and represent everything in two numbers.
>
> Or use strings ...

JSON types are variant.  We could send integers great than 53-bits back 
as strings..  This would break libvirt badly though.

> Rich.