Re: [Qemu-devel] [PATCH v2 1/2] qapi: Allow decimal values

[Eric Blake]

On 04/29/2014 03:44 AM, Fam Zheng wrote:
> This allows giving decimal constants in the schema as expr.
> 
> Signed-off-by: Fam Zheng <address@hidden>
> ---
>  scripts/qapi.py | 15 +++++++++++++--
>  1 file changed, 13 insertions(+), 2 deletions(-)
> 
> diff --git a/scripts/qapi.py b/scripts/qapi.py
> index b474c39..6022de5 100644
> --- a/scripts/qapi.py
> +++ b/scripts/qapi.py
> @@ -108,6 +108,14 @@ class QAPISchema:
>                          return
>                      else:
>                          string += ch
> +            elif self.tok in "123456789":
> +                self.val = int(self.tok)
> +                while True:
> +                    ch = self.src[self.cursor]
> +                    if ch not in "1234567890":
> +                        return
> +                    self.val = self.val * 10 + int(ch)
> +                    self.cursor += 1

What does this do on integer overflow?  Should you validate that the
result fits in [u]int64_t?  Should you allow for a leading '-' sign for
a default of a negative number?  You have forbidden '0' as a valid
number (although you correctly forbid '00' and any non-zero number with
a leading 0, which matches JSON restrictions).

> -        if not self.tok in [ '{', '[', "'" ]:
> -            raise QAPISchemaError(self, 'Expected "{", "[", "]" or string')
> +        if not self.tok in "{['123456789":
> +            raise QAPISchemaError(self, 'Expected "{", "[", "]", string or 
> number')

Again, this forbids the use of '0' as a default.

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

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