From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists1p.gnu.org (lists1p.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 009D8CD98C5 for ; Mon, 15 Jun 2026 08:11:42 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists1p.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1wZ2Ps-0000rd-M6; Mon, 15 Jun 2026 04:11:32 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists1p.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1wZ2Pr-0000of-Jw for qemu-devel@nongnu.org; Mon, 15 Jun 2026 04:11:31 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1wZ2Pp-0001jj-GG for qemu-devel@nongnu.org; Mon, 15 Jun 2026 04:11:30 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1781511087; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=ZhA39Yvx0p6sgB3mCXfl0JfeG0XgVFzx7f2+Io1Psp0=; b=JRkstwn4M+u3Uhqzb080dtPzOOi6fbIhMdQ7tQBej3HNKzZC8e0jYqv0xruPTujQCZEu2Z IHqJjTPp7ynDo83q+ZWBp9XJmcmFZl3zHfmc/EWR+DhSBbdIb+gpxVkNX+zuM1qCVwTAMJ 4Mlkf1QOK54pWiDcjtU9ZN4ez5IAYi8= Received: from mx-prod-mc-05.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-78-Fd5oOG8_MTyymlfQ4pk05Q-1; Mon, 15 Jun 2026 04:11:26 -0400 X-MC-Unique: Fd5oOG8_MTyymlfQ4pk05Q-1 X-Mimecast-MFC-AGG-ID: Fd5oOG8_MTyymlfQ4pk05Q_1781511085 Received: from mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.111]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 6DA0119560A1 for ; Mon, 15 Jun 2026 08:11:25 +0000 (UTC) Received: from blackfin.pond.sub.org (unknown [10.44.22.4]) by mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 2BA32180049F for ; Mon, 15 Jun 2026 08:11:24 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id 9455021E6A01; Mon, 15 Jun 2026 10:11:22 +0200 (CEST) From: Markus Armbruster To: Paolo Bonzini Cc: qemu-devel@nongnu.org Subject: Re: [PATCH v3 4/7] json-streamer: make brace/bracket count unsigned In-Reply-To: <20260525150503.393743-5-pbonzini@redhat.com> (Paolo Bonzini's message of "Mon, 25 May 2026 17:05:00 +0200") References: <20260525150503.393743-1-pbonzini@redhat.com> <20260525150503.393743-5-pbonzini@redhat.com> Date: Mon, 15 Jun 2026 10:11:22 +0200 Message-ID: <877bo0rzo5.fsf@pond.sub.org> User-Agent: Gnus/5.13 (Gnus v5.13) MIME-Version: 1.0 Content-Type: text/plain X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.111 Received-SPF: pass client-ip=170.10.133.124; envelope-from=armbru@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: 8 X-Spam_score: 0.8 X-Spam_bar: / X-Spam_report: (0.8 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.445, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H5=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_SBL_CSS=3.335, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: qemu development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Paolo Bonzini writes: > It makes no sense to let brace_count and bracket_count go negative, > also because it immediately ends error recovery and sets them both > back to zero. Instead set them to zero *before* choosing > whether to process the token queue; this makes it possible to > have the fields as unsigned. > > Note that JSON_END_OF_INPUT now forces the parentheses to appear > balanced, so that the queue is emptied and an error is reported; > hence, the "type != JSON_END_OF_INPUT" condition can be removed. > > Signed-off-by: Paolo Bonzini > --- > include/qobject/json-parser.h | 4 ++-- > qobject/json-streamer.c | 19 ++++++++++++++++--- > 2 files changed, 18 insertions(+), 5 deletions(-) > > diff --git a/include/qobject/json-parser.h b/include/qobject/json-parser.h > index 4c3d89f751f..0cf6932ecdc 100644 > --- a/include/qobject/json-parser.h > +++ b/include/qobject/json-parser.h > @@ -31,8 +31,8 @@ typedef struct JSONMessageParser { > void *opaque; > JSONLexer lexer; > JSONParserContext parser; > - int brace_count; > - int bracket_count; > + unsigned int brace_count; > + unsigned int bracket_count; > GQueue tokens; > uint64_t token_size; > } JSONMessageParser; > diff --git a/qobject/json-streamer.c b/qobject/json-streamer.c > index f3dfdcaea12..b0bf2083ca6 100644 > --- a/qobject/json-streamer.c > +++ b/qobject/json-streamer.c > @@ -41,12 +41,18 @@ void json_message_process_token(JSONLexer *lexer, GString *input, > parser->brace_count++; > break; > case JSON_RCURLY: > + if (parser->brace_count <= 0) { Why <= 0? parser->brace_count is unsigned now... > + goto end_error_recovery; > + } > parser->brace_count--; > break; > case JSON_LSQUARE: > parser->bracket_count++; > break; > case JSON_RSQUARE: > + if (parser->bracket_count <= 0) { Likewise. > + goto end_error_recovery; > + } > parser->bracket_count--; > break; > case JSON_ERROR: > @@ -56,6 +62,15 @@ void json_message_process_token(JSONLexer *lexer, GString *input, > if (g_queue_is_empty(&parser->tokens)) { > return; > } > + end_error_recovery: > + /* > + * Cause error recovery to end immediately. > + * If not in error recovery, the parser will raise an error > + * (due to JSON_ERROR or unexpected JSON_R{CURLY,SQUARE}) What do you mean by "due to JSON_ERROR"? We get here on unmatched } or ]: that's the gotos you add above. We also get here on end of non-empty input: that's when the if right above doesn't return. > + * but error recovery won't be entered at all. > + */ This is the only comment on error recovery. Would a comment giving a brief overview on error recovery be useful? > + parser->brace_count = 0; > + parser->bracket_count = 0; > break; > default: > break; > @@ -83,9 +98,7 @@ void json_message_process_token(JSONLexer *lexer, GString *input, > > g_queue_push_tail(&parser->tokens, token); > > - if ((parser->brace_count > 0 || parser->bracket_count > 0) > - && parser->brace_count >= 0 && parser->bracket_count >= 0 > - && type != JSON_END_OF_INPUT) { > + if (parser->brace_count > 0 || parser->bracket_count > 0) { > return; > } We get here when * no lexical error, and * no limits exceeded, and * the curlies and squares are balanced, either in fact or because we passed through end_error_recovery. Good. /* Process all tokens in the queue */ while (!g_queue_is_empty(&parser->tokens)) {