On 4/2/20 7:13 AM, Simran Singhal wrote:
> Remove the duplicate test "parser->bracket_count >= 0".
>
> Signed-off-by: Simran Singhal <address@hidden>
> ---
> qobject/json-streamer.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/qobject/json-streamer.c b/qobject/json-streamer.c
> index 47dd7ea576..ef48185283 100644
> --- a/qobject/json-streamer.c
> +++ b/qobject/json-streamer.c
> @@ -85,7 +85,7 @@ void json_message_process_token(JSONLexer *lexer, GString *input,
> g_queue_push_tail(&parser->tokens, token);
>
Adding some context:
> if ((parser->brace_count > 0 || parser->bracket_count > 0)
> - && parser->bracket_count >= 0 && parser->bracket_count >= 0) {
> + && parser->bracket_count >= 0) {
> return;
> }
>
> json = json_parser_parse(parser->tokens, parser->ap, &err);
> parser->tokens = NULL;
>
> out_emit:
This code was rewritten in commit 8d3265b3. Prior to that, it read:
if (parser->brace_count < 0 ||
parser->bracket_count < 0 ||
(parser->brace_count == 0 &&
parser->bracket_count == 0)) {
json = json_parser_parse(parser->tokens, parser->ap, &err);
parser->tokens = NULL;
goto out_emit;
}
return;
out_emit:
Obviously, the goal of the rewrite was to convert:
if (cond) {
do stuff
} else {
return
}
more stuff
into the more legible
if (!cond) {
return
}
do stuff
more stuff
Let's re-read my original review:
https://lists.gnu.org/archive/html/qemu-devel/2018-08/msg03017.html
> Applying deMorgan's rules:
>
> !(brace < 0 || bracket < 0 || (brace == 0 && bracket == 0))
> !(brace < 0) && !(bracket < 0) && !(brace == 0 && bracket == 0)
> brace >= 0 && bracket >= 0 && (!(brace == 0) || !(bracket == 0))
> brace >= 0 && bracket >= 0 && (brace != 0 || bracket != 0)
>
> But based on what we learned in the first two conjunctions, we can rewrite the third:
>
>
> brace >= 0 && bracket >= 0 && (brace > 0 || bracket > 0)
>
> and then commute the logic:
>
> (brace > 0 || bracket > 0) && brace >= 0 && bracket >= 0
>
What I missed was the typo: we checked bracket >= 0 twice, instead of
the intended brace >= 0 && bracket >= 0. This needs a v2.
Hello Eric,
Thanks for the explanation.
I'll send v2 with the required changes.
--
Simran
--
Eric Blake, Principal Software Engineer
Red Hat, Inc. +1-919-301-3226
Virtualization: qemu.org | libvirt.org