[{"id":33870,"web_url":"https://patchwork.libcamera.org/comment/33870/","msgid":"<20250401214522.GH3494@pendragon.ideasonboard.com>","date":"2025-04-01T21:45:22","subject":"Re: [PATCH v1 3/4] libcamera: controls: Arrays of arrays are not\n\tsupported","submitter":{"id":2,"url":"https://patchwork.libcamera.org/api/people/2/","name":"Laurent Pinchart","email":"laurent.pinchart@ideasonboard.com"},"content":"On Tue, Apr 01, 2025 at 03:19:38PM +0200, Barnabás Pőcze wrote:\n> Arrays of arrays, even arrays of strings, are not supported by\n> the current `ControlValue` mechanism, so disable them to trigger\n> comptime errors if attempts are made to use them.\n\nWhat currently happens if we try to use them ?\n\n> Signed-off-by: Barnabás Pőcze \n> ---\n> include/libcamera/controls.h | 2 +-\n> src/apps/cam/capture_script.cpp | 4 ----\n> 2 files changed, 1 insertion(+), 5 deletions(-)\n> \n> diff --git a/include/libcamera/controls.h b/include/libcamera/controls.h\n> index d35347f4c..85c724ec1 100644\n> --- a/include/libcamera/controls.h\n> +++ b/include/libcamera/controls.h\n> @@ -120,7 +120,7 @@ struct control_type {\n> };\n> \n> template\n> -struct control_type> : public control_type> {\n> +struct control_type, std::enable_if_t>::size == 0>> : public control_type> {\n> \tstatic constexpr std::size_t size = N;\n> };\n> \n> diff --git a/src/apps/cam/capture_script.cpp b/src/apps/cam/capture_script.cpp\n> index fc1dfa75f..f3262af98 100644\n> --- a/src/apps/cam/capture_script.cpp\n> +++ b/src/apps/cam/capture_script.cpp\n> @@ -600,10 +600,6 @@ ControlValue CaptureScript::parseArrayControl(const ControlId *id,\n> \t\tvalue = Span(values.data(), values.size());\n> \t\tbreak;\n> \t}\n> -\tcase ControlTypeString: {\n> -\t\tvalue = Span(repr.data(), repr.size());\n> -\t\tbreak;\n> -\t}\n> \tdefault:\n> \t\tstd::cerr << \"Unsupported control type\" << std::endl;\n> \t\tbreak;","headers":{"Return-Path":"","X-Original-To":"parsemail@patchwork.libcamera.org","Delivered-To":"parsemail@patchwork.libcamera.org","Received":["from lancelot.ideasonboard.com (lancelot.ideasonboard.com\n\t[92.243.16.209])\n\tby patchwork.libcamera.org (Postfix) with ESMTPS id 32459C3213\n\tfor ;\n\tTue, 1 Apr 2025 21:45:52 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id 6F84168962;\n\tTue, 1 Apr 2025 23:45:51 +0200 (CEST)","from perceval.ideasonboard.com (perceval.ideasonboard.com\n\t[IPv6:2001:4b98:dc2:55:216:3eff:fef7:d647])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id EEFE968947\n\tfor ;\n\tTue, 1 Apr 2025 23:45:48 +0200 (CEST)","from pendragon.ideasonboard.com (81-175-209-231.bb.dnainternet.fi\n\t[81.175.209.231])\n\tby perceval.ideasonboard.com (Postfix) with ESMTPSA id E6ED5741;\n\tTue, 1 Apr 2025 23:43:55 +0200 (CEST)"],"Authentication-Results":"lancelot.ideasonboard.com; dkim=pass (1024-bit key;\n\tunprotected) header.d=ideasonboard.com header.i=@ideasonboard.com\n\theader.b=\"r3mAw6Gb\"; dkim-atps=neutral","DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com;\n\ts=mail; t=1743543836;\n\tbh=LUmG8DUH+28OLQS4gB5npGajZBOmxMSAPVM1yCAK2mM=;\n\th=Date:From:To:Cc:Subject:References:In-Reply-To:From;\n\tb=r3mAw6GbyP+zCGQMUnIqcUYDx+rVCQCy5fsKBrAFliOIljIVgjXV2MeuMvl+/iv+h\n\tLG8Xzo3HEvtlbq5lpoi2OJ+74AvCM3RAPTkxeQm/+sP+AJvWIApVNhhg4MO0ejzFiI\n\t91nCmrOjUPCv1grD8SPeaR9und+cNeqfTZS3UAm8=","Date":"Wed, 2 Apr 2025 00:45:22 +0300","From":"Laurent Pinchart ","To":"=?utf-8?q?Barnab=C3=A1s_P=C5=91cze?= ","Cc":"libcamera-devel@lists.libcamera.org","Subject":"Re: [PATCH v1 3/4] libcamera: controls: Arrays of arrays are not\n\tsupported","Message-ID":"<20250401214522.GH3494@pendragon.ideasonboard.com>","References":"<20250401131939.749583-1-barnabas.pocze@ideasonboard.com>\n\t<20250401131939.749583-4-barnabas.pocze@ideasonboard.com>","MIME-Version":"1.0","Content-Type":"text/plain; charset=utf-8","Content-Disposition":"inline","Content-Transfer-Encoding":"8bit","In-Reply-To":"<20250401131939.749583-4-barnabas.pocze@ideasonboard.com>","X-BeenThere":"libcamera-devel@lists.libcamera.org","X-Mailman-Version":"2.1.29","Precedence":"list","List-Id":"","List-Unsubscribe":",\n\t","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n\t","Errors-To":"libcamera-devel-bounces@lists.libcamera.org","Sender":"\"libcamera-devel\" "}},{"id":33879,"web_url":"https://patchwork.libcamera.org/comment/33879/","msgid":"","date":"2025-04-02T08:25:44","subject":"Re: [PATCH v1 3/4] libcamera: controls: Arrays of arrays are not\n\tsupported","submitter":{"id":216,"url":"https://patchwork.libcamera.org/api/people/216/","name":"Barnabás Pőcze","email":"barnabas.pocze@ideasonboard.com"},"content":"Hi\n\n\n2025. 04. 01. 23:45 keltezéssel, Laurent Pinchart írta:\n> On Tue, Apr 01, 2025 at 03:19:38PM +0200, Barnabás Pőcze wrote:\n>> Arrays of arrays, even arrays of strings, are not supported by\n>> the current `ControlValue` mechanism, so disable them to trigger\n>> comptime errors if attempts are made to use them.\n> \n> What currently happens if we try to use them ?\n\nThere are two options I can see:\n\n * runtime assertion failure in `set()` because `elementSize == ControlValueSize[type]`\n is not true, e.g. `Span`\n * stores spans inside `ControlValue` (with arbitrarily dangling pointers),\n e.g. `Span>` (since `sizeof(Span) == sizeof(Rectangle)`\n on x86-64)\n\nSo they don't really work in any reasonable capacity,\nthis is why I want to disable them for now.\n\n\nRegards,\nBarnabás Pőcze\n\n> \n>> Signed-off-by: Barnabás Pőcze \n>> ---\n>> include/libcamera/controls.h | 2 +-\n>> src/apps/cam/capture_script.cpp | 4 ----\n>> 2 files changed, 1 insertion(+), 5 deletions(-)\n>>\n>> diff --git a/include/libcamera/controls.h b/include/libcamera/controls.h\n>> index d35347f4c..85c724ec1 100644\n>> --- a/include/libcamera/controls.h\n>> +++ b/include/libcamera/controls.h\n>> @@ -120,7 +120,7 @@ struct control_type {\n>> };\n>> \n>> template\n>> -struct control_type> : public control_type> {\n>> +struct control_type, std::enable_if_t>::size == 0>> : public control_type> {\n>> \tstatic constexpr std::size_t size = N;\n>> };\n>> \n>> diff --git a/src/apps/cam/capture_script.cpp b/src/apps/cam/capture_script.cpp\n>> index fc1dfa75f..f3262af98 100644\n>> --- a/src/apps/cam/capture_script.cpp\n>> +++ b/src/apps/cam/capture_script.cpp\n>> @@ -600,10 +600,6 @@ ControlValue CaptureScript::parseArrayControl(const ControlId *id,\n>> \t\tvalue = Span(values.data(), values.size());\n>> \t\tbreak;\n>> \t}\n>> -\tcase ControlTypeString: {\n>> -\t\tvalue = Span(repr.data(), repr.size());\n>> -\t\tbreak;\n>> -\t}\n>> \tdefault:\n>> \t\tstd::cerr << \"Unsupported control type\" << std::endl;\n>> \t\tbreak;\n>","headers":{"Return-Path":"","X-Original-To":"parsemail@patchwork.libcamera.org","Delivered-To":"parsemail@patchwork.libcamera.org","Received":["from lancelot.ideasonboard.com (lancelot.ideasonboard.com\n\t[92.243.16.209])\n\tby patchwork.libcamera.org (Postfix) with ESMTPS id E9BABC3213\n\tfor ;\n\tWed, 2 Apr 2025 08:25:50 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id 4131068981;\n\tWed, 2 Apr 2025 10:25:50 +0200 (CEST)","from perceval.ideasonboard.com (perceval.ideasonboard.com\n\t[IPv6:2001:4b98:dc2:55:216:3eff:fef7:d647])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id D728C68979\n\tfor ;\n\tWed, 2 Apr 2025 10:25:48 +0200 (CEST)","from [192.168.33.20] (185.221.143.221.nat.pool.zt.hu\n\t[185.221.143.221])\n\tby perceval.ideasonboard.com (Postfix) with ESMTPSA id EBD8C415;\n\tWed, 2 Apr 2025 10:23:55 +0200 (CEST)"],"Authentication-Results":"lancelot.ideasonboard.com; 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