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Lima" , , Subject: Re: [PATCH v3] rust: transmute: add `as_bytes` method for `AsBytes` trait From: "Alexandre Courbot" To: "Benno Lossin" , "Alice Ryhl" X-Mailer: aerc 0.20.1-0-g2ecb8770224a-dirty References: <20250726-as_bytes-v3-1-eb7514faab28@nvidia.com> In-Reply-To: X-ClientProxiedBy: TYCPR01CA0133.jpnprd01.prod.outlook.com (2603:1096:400:26d::14) To CH2PR12MB3990.namprd12.prod.outlook.com (2603:10b6:610:28::18) Precedence: bulk X-Mailing-List: rust-for-linux@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: CH2PR12MB3990:EE_|IA1PR12MB6651:EE_ X-MS-Office365-Filtering-Correlation-Id: 62e0b15f-39f7-400a-8f63-08ddcd885e51 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|7416014|376014|1800799024|366016|10070799003; X-Microsoft-Antispam-Message-Info: =?utf-8?B?WXVjRmFaZFRhZ3pBbHBveFE5RW51N3laWDhYQ1U1VE1MdU05U1Z3QlFYUlRz?= =?utf-8?B?Y1dNYVljSXAwdzNGZ3VuY01kbkNmSCtnQk1mbmFYZE1SNTRTNFNIaUQ5QjFq?= =?utf-8?B?ay84Y2pYUFp5OVZnZ1A2VXozYVAxRmt6emc4Y24wb0tUT0VBeGJ3U3hKK1B4?= =?utf-8?B?QzcxdnlsYUNSbThjMzdkQitKTW56QWIzU0s2TWV6VTkwcGo0SXgyMVp6L3hM?= =?utf-8?B?M1gwMS9PRUVrZHFKcmErNUY1WG9pMldScVN3eU1SbFdNWldaS2JDQ01DOGxR?= =?utf-8?B?MzRRUG1FUXNta3U5aC8wU1VVLzVudE43TDlNcENieERBbUVscUVWdDBacWg0?= =?utf-8?B?YUZLd1IrOXhHR3JiSmkxeXBnUS9xeFo5R2trZWppL3RZUFQyaDRSY0FvSWNi?= =?utf-8?B?RDRyN2JTNTdKRFBkMEcvRzM5c2FuNjY0MHFIRjNhWHE4ekNJNzJmSkwyV3Zi?= =?utf-8?B?b3NOREZOTitucjkrWWhxYU0zWlY5MG9MOCtqK05IaG1iVllGUkZic0RxdUt1?= =?utf-8?B?b2tvM1dybDhYOWMvelVXdndRMXFLNDgvUXI1ZzVVNXVJOGtkZjRvcVFpQlhy?= =?utf-8?B?ZVhIZFQyZkxITDJtTHB1ZTNGQVR0VXZLdkpndlVRaVNRbzdubVlOWjJuekhS?= =?utf-8?B?QUVMU1dOQ3c1blpGMW9teU5iZUgwei9TajdiNVFVYkJMd2JWckFGOEdWRHNr?= =?utf-8?B?Q01HWll1c1oxaG00eGNiTC9DTEJHaGc1aDhKR0ZhNUozT1dIUzU5R0V5Y1RP?= =?utf-8?B?WEQzREJxZmlKMFVpVHcvTjdqTUkzZ0xPdmNiUzRUejZib2w3SDRmVXZXRGh2?= =?utf-8?B?OWQrSkhGb1B5SnFMeWswNlFnTk1pWUJCNnZPaUtBanpaV1N0bE9NalpzUnlL?= =?utf-8?B?b0QxeGczSlAzcmRweWFNZ3duMFA0OVd3VXpSTjZPa1JoTkkzZmw2ZytiQzBS?= =?utf-8?B?a3FRcFhhTDVWMVJzMUJucm91dTNLaStQT3dEVmVyTlpQT3RTalhiRU1kZFYw?= =?utf-8?B?M2V4YjN4ZURXM1UwTTV1M2o3Tm81cUZxbStCNnZyemdzeU9QeWswMUN2QUhh?= =?utf-8?B?akIvWHM4Rlo1L3Zhdno1ZDR3SjkvS3NvTVpTSkRUdkZ3OWpZeENRb0F6b29M?= =?utf-8?B?MkZ4RXh4amt6NmVNYWZZdmZMazBYcW1Wc0xJcytpekRoamVoQjZJRm1OcUNj?= =?utf-8?B?OUpOTjB4dkZpZjUzTFYvUlNzOFQ1N1g5WTR6d0Y5SWJJZzBsR01Tc3V5TGc1?= =?utf-8?B?ZlBPZmE4Mm02c3RucmZwZ2cxaXMwcW1zNEV1UkpiVUdvN3ovV2NJWWFKZUxo?= =?utf-8?B?Zk1mVk5tYWJCNnQvQTVraGwvVmlMRTVQc2lscmhnSC9YSys3NnZzVFlma3h3?= =?utf-8?B?Z290dlVTUEQ0UGhTL2xmalEvTHd5Uk93WXJGZEhScmtaQkZjMzRJeG5sNFNa?= =?utf-8?B?ajNmNFRUQ3N5RHJidTJydUZwSE1MdkhRRU4xOEQ2NEpKQk5vMXFTVFhnRE4y?= =?utf-8?B?VWtPL3ZyMTJyenBrNHcwRjlrdGNaaFFHK2xRNGdMekkxbGM5UVNoVHhoaGM2?= =?utf-8?B?eUtjWndTUFArMWt6V0U4QnhNNjU1enRWc2Z0clNKczBnSkRsNE1USlMzWllM?= =?utf-8?B?K2h6TmJ4bVhKSUZvYm1wQlVmUW4vRDhNZ1cyM09DM0lOck9RNFpkYWI3QU1M?= =?utf-8?B?bUhlU0ZhaGtBNFFRREdJSFgzR1NEejRCa1ZSUXBDc3Y2VUtlaGlhT3dDeEtp?= =?utf-8?B?akFGQzM2Vy92QldWVU5GRGdFM01TRVBIQWxvYzVvQ0JjR2sxbVkzaE9rcnk1?= =?utf-8?B?MWZxclFOdnRodTJkNjc4K3BpNDdyVlc3QjNqYm5MbEF6bEROTFVuWVluM3Fo?= =?utf-8?B?VENFVElXU1M1eE15Q2dIcEJ2d3JjWHBkcS9WU2hTR2JZViszZzZ3czVXb2ln?= =?utf-8?Q?ebJCUr96Y2A=3D?= X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:CH2PR12MB3990.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(7416014)(376014)(1800799024)(366016)(10070799003);DIR:OUT;SFP:1101; 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Thi= s type must not have interior >>> > /// mutability. >>> > -pub unsafe trait AsBytes {} >>> > +pub unsafe trait AsBytes { >>> > + /// Returns `self` as a slice of bytes. >>> > + fn as_bytes(&self) -> &[u8] { >>> > + let data =3D core::ptr::from_ref(self).cast::(); >>> > + let len =3D size_of_val(self); >>> > + >>> > + // SAFETY: `data` is non-null and valid for `len * sizeof::<= u8>()` bytes. >>> > + unsafe { core::slice::from_raw_parts(data, len) } >>> > + } >>> > +} >>>=20 >>> Let's also have an as_bytes_mut() method. I would require the type to >>> also implement FromBytes as it lets you replace the value with another >>> set of bytes. >> >> s/I would/It would/ >> >> FromBytes is needed only for as_bytes_mut(), not for the existing >> method. > > I agree with your suggestion, but it can be an independent patch and > doesn't need to go in via this one, right? Given where we are in the merge cycle, it seems like we have a couple of months until that code gets merged anyway, so I don't see any reason to not send a v4 with Alice's suggestion? The only drawback I see is that I would have to reset the Reviewed-by tags.