Re: [Qemu-devel] [PATCH v2 08/18] json-parser: simplify and avoid JSONParserContext allocation

[Markus Armbruster]

Marc-André Lureau <address@hidden> writes:

> parser_context_new/free() are only used from json_parser_parse(). We
> can fold the code there and avoid an allocation altogether.
>
> Signed-off-by: Marc-André Lureau <address@hidden>
> ---
>  qobject/json-parser.c | 41 +++++++++--------------------------------
>  1 file changed, 9 insertions(+), 32 deletions(-)
>
> diff --git a/qobject/json-parser.c b/qobject/json-parser.c
> index 9a7004e680..6baf73b4b9 100644
> --- a/qobject/json-parser.c
> +++ b/qobject/json-parser.c
> @@ -244,33 +244,6 @@ static JSONToken 
> *parser_context_peek_token(JSONParserContext *ctxt)
>      return g_queue_peek_head(ctxt->buf);
>  }
>  
> -static JSONParserContext *parser_context_new(GQueue *tokens)
> -{
> -    JSONParserContext *ctxt;
> -
> -    if (!tokens) {
> -        return NULL;
> -    }
> -
> -    ctxt = g_malloc0(sizeof(JSONParserContext));
> -    ctxt->buf = tokens;
> -
> -    return ctxt;
> -}
> -
> -/* to support error propagation, ctxt->err must be freed separately */
> -static void parser_context_free(JSONParserContext *ctxt)
> -{
> -    if (ctxt) {
> -        while (!g_queue_is_empty(ctxt->buf)) {
> -            parser_context_pop_token(ctxt);
> -        }
> -        g_free(ctxt->current);
> -        g_queue_free(ctxt->buf);
> -        g_free(ctxt);
> -    }
> -}
> -
>  /**
>   * Parsing rules
>   */
> @@ -577,18 +550,22 @@ static QObject *parse_value(JSONParserContext *ctxt, 
> va_list *ap)
>  
>  QObject *json_parser_parse(GQueue *tokens, va_list *ap, Error **errp)
>  {
> -    JSONParserContext *ctxt = parser_context_new(tokens);
> +    JSONParserContext ctxt = { .buf = tokens };
>      QObject *result;
>  
> -    if (!ctxt) {
> +    if (!tokens) {
>          return NULL;
>      }
>  
> -    result = parse_value(ctxt, ap);
> +    result = parse_value(&ctxt, ap);
>  
> -    error_propagate(errp, ctxt->err);
> +    error_propagate(errp, ctxt.err);
>  
> -    parser_context_free(ctxt);
> +    while (!g_queue_is_empty(ctxt.buf)) {
> +        parser_context_pop_token(&ctxt);
> +    }
> +    g_free(ctxt.current);
> +    g_queue_free(ctxt.buf);
>  
>      return result;
>  }

A lovely simplification.

Reviewed-by: Markus Armbruster <address@hidden>