[{"id":14973,"web_url":"https://patchwork.libcamera.org/comment/14973/","msgid":"","date":"2021-02-04T16:37:42","subject":"Re: [libcamera-devel] [PATCH] android: jpeg: Utilise compiler\n\tspecific nodiscard","submitter":{"id":2,"url":"https://patchwork.libcamera.org/api/people/2/","name":"Laurent Pinchart","email":"laurent.pinchart@ideasonboard.com"},"content":"Hi Kieran,\n\nThank you for the patch.\n\nOn Thu, Feb 04, 2021 at 02:37:36PM +0000, Kieran Bingham wrote:\n> Utilise the new compiler specific __nodiscard to maintain coding style.\n> \n> Signed-off-by: Kieran Bingham \n> ---\n> \n> Only applicable along with Laurent's [[nodiscard]] series.\n\nI'm open to discussing this, but as replied in another e-mail, I was\nenvisioning the __nodiscard macro as a temporary fix until we declare\nthe public API to require C++17. I was annoyed by the C++ [[...]]\nattributes initially, but after some time I got used to them and I don't\nmind them anymore. Using native language features is usually better from\na readability point of view compared to wrapping them in custom macros,\nas the latter needs additional knowledge from the reader.\n\n> src/android/jpeg/exif.cpp | 2 +-\n> src/android/jpeg/exif.h | 3 ++-\n> 2 files changed, 3 insertions(+), 2 deletions(-)\n> \n> diff --git a/src/android/jpeg/exif.cpp b/src/android/jpeg/exif.cpp\n> index fdd46070ba7c..ed995ca13167 100644\n> --- a/src/android/jpeg/exif.cpp\n> +++ b/src/android/jpeg/exif.cpp\n> @@ -515,7 +515,7 @@ std::u16string Exif::utf8ToUtf16(const std::string &str)\n> \treturn ret;\n> }\n> \n> -[[nodiscard]] int Exif::generate()\n> +__nodiscard int Exif::generate()\n> {\n> \tif (exifData_) {\n> \t\tfree(exifData_);\n> diff --git a/src/android/jpeg/exif.h b/src/android/jpeg/exif.h\n> index b0d614027ede..67dbd20524d8 100644\n> --- a/src/android/jpeg/exif.h\n> +++ b/src/android/jpeg/exif.h\n> @@ -13,6 +13,7 @@\n> \n> #include \n> \n> +#include \n> #include \n> #include \n> \n> @@ -75,7 +76,7 @@ public:\n> \tvoid setWhiteBalance(WhiteBalance wb);\n> \n> \tlibcamera::Span data() const { return { exifData_, size_ }; }\n> -\t[[nodiscard]] int generate();\n> +\t__nodiscard int generate();\n> \n> private:\n> \tExifEntry *createEntry(ExifIfd ifd, ExifTag tag);","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 7CFD7BD162\n\tfor ;\n\tThu, 4 Feb 2021 16:38:07 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id 0665661445;\n\tThu, 4 Feb 2021 17:38:07 +0100 (CET)","from perceval.ideasonboard.com (perceval.ideasonboard.com\n\t[213.167.242.64])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id 871B561430\n\tfor ;\n\tThu, 4 Feb 2021 17:38:05 +0100 (CET)","from pendragon.ideasonboard.com (62-78-145-57.bb.dnainternet.fi\n\t[62.78.145.57])\n\tby perceval.ideasonboard.com (Postfix) with ESMTPSA id EEE9B510;\n\tThu, 4 Feb 2021 17:38:04 +0100 (CET)"],"Authentication-Results":"lancelot.ideasonboard.com;\n\tdkim=fail reason=\"signature verification failed\" (1024-bit key;\n\tunprotected) header.d=ideasonboard.com header.i=@ideasonboard.com\n\theader.b=\"W+DIT1qb\"; dkim-atps=neutral","DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com;\n\ts=mail; t=1612456685;\n\tbh=C0g0bfUcVHqzLYujJP4dEbibPMrjvRsWA4bRLUS/R7A=;\n\th=Date:From:To:Cc:Subject:References:In-Reply-To:From;\n\tb=W+DIT1qbSZSJuhvTmlzGZ411E4Pr2si7PcWzSMGSfBD1YwNy/xTojWDqMcLW2F2zp\n\t0t2304AHn4xDiJWi5rtrecz+00/KALG2hc/J2kYI4FAUC6M9vFmquQ1IcyZ43ZfDN/\n\taf0Fwl/BUMwT5fvzF0KmZ4YUTQPycAL3MRlZ2DiE=","Date":"Thu, 4 Feb 2021 18:37:42 +0200","From":"Laurent Pinchart ","To":"Kieran Bingham ","Message-ID":"","References":"<20210204035951.23751-1-laurent.pinchart@ideasonboard.com>\n\t<20210204143736.1762344-1-kieran.bingham@ideasonboard.com>","MIME-Version":"1.0","Content-Disposition":"inline","In-Reply-To":"<20210204143736.1762344-1-kieran.bingham@ideasonboard.com>","Subject":"Re: [libcamera-devel] [PATCH] android: jpeg: Utilise compiler\n\tspecific nodiscard","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","Cc":"libcamera devel ","Content-Type":"text/plain; charset=\"us-ascii\"","Content-Transfer-Encoding":"7bit","Errors-To":"libcamera-devel-bounces@lists.libcamera.org","Sender":"\"libcamera-devel\" "}},{"id":14974,"web_url":"https://patchwork.libcamera.org/comment/14974/","msgid":"<9dbc1b33-f65f-ccf9-4921-12925f94d5e7@ideasonboard.com>","date":"2021-02-04T16:49:20","subject":"Re: [libcamera-devel] [PATCH] android: jpeg: Utilise compiler\n\tspecific nodiscard","submitter":{"id":4,"url":"https://patchwork.libcamera.org/api/people/4/","name":"Kieran Bingham","email":"kieran.bingham@ideasonboard.com"},"content":"Hi Laurent,\n\nOn 04/02/2021 16:37, Laurent Pinchart wrote:\n> Hi Kieran,\n> \n> Thank you for the patch.\n> \n> On Thu, Feb 04, 2021 at 02:37:36PM +0000, Kieran Bingham wrote:\n>> Utilise the new compiler specific __nodiscard to maintain coding style.\n>>\n>> Signed-off-by: Kieran Bingham \n>> ---\n>>\n>> Only applicable along with Laurent's [[nodiscard]] series.\n> \n> I'm open to discussing this, but as replied in another e-mail, I was\n> envisioning the __nodiscard macro as a temporary fix until we declare\n> the public API to require C++17. I was annoyed by the C++ [[...]]\n\nYup, I find it a little 'ugly' but no matter.\n\n> attributes initially, but after some time I got used to them and I don't\n> mind them anymore. Using native language features is usually better from\n> a readability point of view compared to wrapping them in custom macros,\n> as the latter needs additional knowledge from the reader.\n\nDon't worry - if this is temporary, then don't worry about this patch.\n--\nKieran\n\n\n> \n>> src/android/jpeg/exif.cpp | 2 +-\n>> src/android/jpeg/exif.h | 3 ++-\n>> 2 files changed, 3 insertions(+), 2 deletions(-)\n>>\n>> diff --git a/src/android/jpeg/exif.cpp b/src/android/jpeg/exif.cpp\n>> index fdd46070ba7c..ed995ca13167 100644\n>> --- a/src/android/jpeg/exif.cpp\n>> +++ b/src/android/jpeg/exif.cpp\n>> @@ -515,7 +515,7 @@ std::u16string Exif::utf8ToUtf16(const std::string &str)\n>> \treturn ret;\n>> }\n>> \n>> -[[nodiscard]] int Exif::generate()\n>> +__nodiscard int Exif::generate()\n>> {\n>> \tif (exifData_) {\n>> \t\tfree(exifData_);\n>> diff --git a/src/android/jpeg/exif.h b/src/android/jpeg/exif.h\n>> index b0d614027ede..67dbd20524d8 100644\n>> --- a/src/android/jpeg/exif.h\n>> +++ b/src/android/jpeg/exif.h\n>> @@ -13,6 +13,7 @@\n>> \n>> #include \n>> \n>> +#include \n>> #include \n>> #include \n>> \n>> @@ -75,7 +76,7 @@ public:\n>> \tvoid setWhiteBalance(WhiteBalance wb);\n>> \n>> \tlibcamera::Span data() const { return { exifData_, size_ }; }\n>> -\t[[nodiscard]] int generate();\n>> +\t__nodiscard int generate();\n>> \n>> private:\n>> \tExifEntry *createEntry(ExifIfd ifd, ExifTag tag);\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 B320FBD160\n\tfor ;\n\tThu, 4 Feb 2021 16:49:25 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id 3F5316144C;\n\tThu, 4 Feb 2021 17:49:25 +0100 (CET)","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 C53A961430\n\tfor ;\n\tThu, 4 Feb 2021 17:49:23 +0100 (CET)","from [192.168.0.20]\n\t(cpc89244-aztw30-2-0-cust3082.18-1.cable.virginm.net [86.31.172.11])\n\tby perceval.ideasonboard.com (Postfix) with ESMTPSA id 307EC510;\n\tThu, 4 Feb 2021 17:49:23 +0100 (CET)"],"Authentication-Results":"lancelot.ideasonboard.com;\n\tdkim=fail reason=\"signature verification failed\" (1024-bit key;\n\tunprotected) header.d=ideasonboard.com header.i=@ideasonboard.com\n\theader.b=\"UfgaxrYp\"; dkim-atps=neutral","DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com;\n\ts=mail; t=1612457363;\n\tbh=5Fp0sd7jRgsPc8YVdbecwLcdvZdt6LXQRzkr6Kh5t7g=;\n\th=Reply-To:Subject:To:Cc:References:From:Date:In-Reply-To:From;\n\tb=UfgaxrYpSRgX+gGygfSmzEip88AcbmKj4FC8VMU9asrui1zygFiNYPUTGkjMZ+oKs\n\thgDVjzgMhR9sjB5SD69gw6eoZB8QqHWNkSJbU9P/chhAEt0R+fYqcUex3FL81z0/LG\n\tMzFLqg39YkebXKNdsFV/VlQlvWQSLE+hhMjKYOyE=","To":"Laurent Pinchart ","References":"<20210204035951.23751-1-laurent.pinchart@ideasonboard.com>\n\t<20210204143736.1762344-1-kieran.bingham@ideasonboard.com>\n\t","From":"Kieran Bingham ","Autocrypt":"addr=kieran.bingham@ideasonboard.com; keydata=\n\tmQINBFYE/WYBEACs1PwjMD9rgCu1hlIiUA1AXR4rv2v+BCLUq//vrX5S5bjzxKAryRf0uHat\n\tV/zwz6hiDrZuHUACDB7X8OaQcwhLaVlq6byfoBr25+hbZG7G3+5EUl9cQ7dQEdvNj6V6y/SC\n\trRanWfelwQThCHckbobWiQJfK9n7rYNcPMq9B8e9F020LFH7Kj6YmO95ewJGgLm+idg1Kb3C\n\tpotzWkXc1xmPzcQ1fvQMOfMwdS+4SNw4rY9f07Xb2K99rjMwZVDgESKIzhsDB5GY465sCsiQ\n\tcSAZRxqE49RTBq2+EQsbrQpIc8XiffAB8qexh5/QPzCmR4kJgCGeHIXBtgRj+nIkCJPZvZtf\n\tKr2EAbc6tgg6DkAEHJb+1okosV09+0+TXywYvtEop/WUOWQ+zo+Y/OBd+8Ptgt1pDRyOBzL8\n\tRXa8ZqRf0Mwg75D+dKntZeJHzPRJyrlfQokngAAs4PaFt6UfS+ypMAF37T6CeDArQC41V3ko\n\tlPn1yMsVD0p+6i3DPvA/GPIksDC4owjnzVX9kM8Zc5Cx+XoAN0w5Eqo4t6qEVbuettxx55gq\n\t8K8FieAjgjMSxngo/HST8TpFeqI5nVeq0/lqtBRQKumuIqDg+Bkr4L1V/PSB6XgQcOdhtd36\n\tOe9X9dXB8YSNt7VjOcO7BTmFn/Z8r92mSAfHXpb07YJWJosQOQARAQABtDBLaWVyYW4gQmlu\n\tZ2hhbSA8a2llcmFuLmJpbmdoYW1AaWRlYXNvbmJvYXJkLmNvbT6JAlcEEwEKAEECGwMFCwkI\n\tBwIGFQgJCgsCBBYCAwECHgECF4ACGQEWIQSQLdeYP70o/eNy1HqhHkZyEKRh/QUCXWTtygUJ\n\tCyJXZAAKCRChHkZyEKRh/f8dEACTDsbLN2nioNZMwyLuQRUAFcXNolDX48xcUXsWS2QjxaPm\n\tVsJx8Uy8aYkS85mdPBh0C83OovQR/OVbr8AxhGvYqBs3nQvbWuTl/+4od7DfK2VZOoKBAu5S\n\tQK2FYuUcikDqYcFWJ8DQnubxfE8dvzojHEkXw0sA4igINHDDFX3HJGZtLio+WpEFQtCbfTAG\n\tYZslasz1YZRbwEdSsmO3/kqy5eMnczlm8a21A3fKUo3g8oAZEFM+f4DUNzqIltg31OAB/kZS\n\tenKZQ/SWC8PmLg/ZXBrReYakxXtkP6w3FwMlzOlhGxqhIRNiAJfXJBaRhuUWzPOpEDE9q5YJ\n\tBmqQL2WJm1VSNNVxbXJHpaWMH1sA2R00vmvRrPXGwyIO0IPYeUYQa3gsy6k+En/aMQJd27dp\n\taScf9am9PFICPY5T4ppneeJLif2lyLojo0mcHOV+uyrds9XkLpp14GfTkeKPdPMrLLTsHRfH\n\tfA4I4OBpRrEPiGIZB/0im98MkGY/Mu6qxeZmYLCcgD6qz4idOvfgVOrNh+aA8HzIVR+RMW8H\n\tQGBN9f0E3kfwxuhl3omo6V7lDw8XOdmuWZNC9zPq1UfryVHANYbLGz9KJ4Aw6M+OgBC2JpkD\n\thXMdHUkC+d20dwXrwHTlrJi1YNp6rBc+xald3wsUPOZ5z8moTHUX/uPA/qhGsbkCDQRWBP1m\n\tARAAzijkb+Sau4hAncr1JjOY+KyFEdUNxRy+hqTJdJfaYihxyaj0Ee0P0zEi35CbE6lgU0Uz\n\ttih9fiUbSV3wfsWqg1Ut3/5rTKu7kLFp15kF7eqvV4uezXRD3Qu4yjv/rMmEJbbD4cTvGCYI\n\td6MDC417f7vK3hCbCVIZSp3GXxyC1LU+UQr3fFcOyCwmP9vDUR9JV0BSqHHxRDdpUXE26Dk6\n\tmhf0V1YkspE5St814ETXpEus2urZE5yJIUROlWPIL+hm3NEWfAP06vsQUyLvr/GtbOT79vXl\n\tEn1aulcYyu20dRRxhkQ6iILaURcxIAVJJKPi8dsoMnS8pB0QW12AHWuirPF0g6DiuUfPmrA5\n\tPKe56IGlpkjc8cO51lIxHkWTpCMWigRdPDexKX+Sb+W9QWK/0JjIc4t3KBaiG8O4yRX8ml2R\n\t+rxfAVKM6V769P/hWoRGdgUMgYHFpHGSgEt80OKK5HeUPy2cngDUXzwrqiM5Sz6Od0qw5pCk\n\tNlXqI0W/who0iSVM+8+RmyY0OEkxEcci7rRLsGnM15B5PjLJjh1f2ULYkv8s4SnDwMZ/kE04\n\t/UqCMK/KnX8pwXEMCjz0h6qWNpGwJ0/tYIgQJZh6bqkvBrDogAvuhf60Sogw+mH8b+PBlx1L\n\toeTK396wc+4c3BfiC6pNtUS5GpsPMMjYMk7kVvEAEQEAAYkCPAQYAQoAJgIbDBYhBJAt15g/\n\tvSj943LUeqEeRnIQpGH9BQJdizzIBQkLSKZiAAoJEKEeRnIQpGH9eYgQAJpjaWNgqNOnMTmD\n\tMJggbwjIotypzIXfhHNCeTkG7+qCDlSaBPclcPGYrTwCt0YWPU2TgGgJrVhYT20ierN8LUvj\n\t6qOPTd+Uk7NFzL65qkh80ZKNBFddx1AabQpSVQKbdcLb8OFs85kuSvFdgqZwgxA1vl4TFhNz\n\tPZ79NAmXLackAx3sOVFhk4WQaKRshCB7cSl+RIng5S/ThOBlwNlcKG7j7W2MC06BlTbdEkUp\n\tECzuuRBv8wX4OQl+hbWbB/VKIx5HKlLu1eypen/5lNVzSqMMIYkkZcjV2SWQyUGxSwq0O/sx\n\tS0A8/atCHUXOboUsn54qdxrVDaK+6jIAuo8JiRWctP16KjzUM7MO0/+4zllM8EY57rXrj48j\n\tsbEYX0YQnzaj+jO6kJtoZsIaYR7rMMq9aUAjyiaEZpmP1qF/2sYenDx0Fg2BSlLvLvXM0vU8\n\tpQk3kgDu7kb/7PRYrZvBsr21EIQoIjXbZxDz/o7z95frkP71EaICttZ6k9q5oxxA5WC6sTXc\n\tMW8zs8avFNuA9VpXt0YupJd2ijtZy2mpZNG02fFVXhIn4G807G7+9mhuC4XG5rKlBBUXTvPU\n\tAfYnB4JBDLmLzBFavQfvonSfbitgXwCG3vS+9HEwAjU30Bar1PEOmIbiAoMzuKeRm2LVpmq4\n\tWZw01QYHU/GUV/zHJSFk","Organization":"Ideas on Board","Message-ID":"<9dbc1b33-f65f-ccf9-4921-12925f94d5e7@ideasonboard.com>","Date":"Thu, 4 Feb 2021 16:49:20 +0000","User-Agent":"Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101\n\tThunderbird/68.10.0","MIME-Version":"1.0","In-Reply-To":"","Content-Language":"en-GB","Subject":"Re: [libcamera-devel] [PATCH] android: jpeg: Utilise compiler\n\tspecific nodiscard","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","Reply-To":"kieran.bingham@ideasonboard.com","Cc":"libcamera devel ","Content-Type":"text/plain; charset=\"us-ascii\"","Content-Transfer-Encoding":"7bit","Errors-To":"libcamera-devel-bounces@lists.libcamera.org","Sender":"\"libcamera-devel\" "}}]