From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7315E2E62C8; Tue, 12 Aug 2025 08:46:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754988386; cv=none; b=PnYRJfxMjEHr/U/Y09Dp4YdH0p7oULIYTwEZmfOYjnZIUndZL8BwJ1LPlvrpk7NOjgab8Mh4g4fOt1nUGn7lEoVmKBDN60xANsFxsVKg9NkfVkmgG4o+9Lo+BxUjrOUYPEi7C6CSc6K5xKos2zRiVWNUwzUzOCGx4ASMWTi4Ll0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754988386; c=relaxed/simple; bh=LiaDRIukgxQ10jLoKnR7ZV1S7vIQx9wTW24ArpjaY5M=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=RhoSsSgEglf51GuxH4RDgR2ATL+Z2fdPG7k8EuVTy4mMt/yLulO2OF1OYIl1gfgBmbT1hqD5f+4kzvTXVCg6SdLcsuudTXIiD6EkSA80wwS75bdNig0Sp0LnSq4zhF3FHlQa8jvKKrUDsLBgXA74dA347ijrbL2Ot6u/hl8wgwQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=ft800Vv2; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="ft800Vv2" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2DF37C4CEF0; Tue, 12 Aug 2025 08:46:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1754988386; bh=LiaDRIukgxQ10jLoKnR7ZV1S7vIQx9wTW24ArpjaY5M=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=ft800Vv23gZxQJ+SZOvHct4qJJRRa0SWIqLK/KMimXn7YYReaEov4BM+h5G5dmVVi 1oUO2ZUXyv7cOqH+J1F5YMNMFsNoAmn45vfH49JjSUL+p/cK7GL7tbEvUmkvMNmLC3 txQmwJIXravQwYbP3Q0G78TuHDmn+lFGjxnYXgWBKuXGdmn4NtK5mxPoey91d5b2lp wOlkxDElAP5C+ilnX+jPeZ1HLycukFnQU//OCwPaNQED29LgbTmhwGVWOxSpQ+E0gv BPKdiNeKFsQXPUCdBqXdAxYyarGk/Gg+WpK5tmCPj5pz/UMakdmX/jquR2GqvbMKdv G/ZMkEqc+siuA== From: Andreas Hindborg Date: Tue, 12 Aug 2025 10:44:20 +0200 Subject: [PATCH v4 02/15] rust: str: allow `str::Formatter` to format into `&mut [u8]`. Precedence: bulk X-Mailing-List: rust-for-linux@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20250812-rnull-up-v6-16-v4-2-ed801dd3ba5c@kernel.org> References: <20250812-rnull-up-v6-16-v4-0-ed801dd3ba5c@kernel.org> In-Reply-To: <20250812-rnull-up-v6-16-v4-0-ed801dd3ba5c@kernel.org> To: Boqun Feng , Miguel Ojeda , Alex Gaynor , Gary Guo , =?utf-8?q?Bj=C3=B6rn_Roy_Baron?= , Benno Lossin , Alice Ryhl , Trevor Gross , Danilo Krummrich , Jens Axboe Cc: linux-block@vger.kernel.org, rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org, Andreas Hindborg X-Mailer: b4 0.15-dev X-Developer-Signature: v=1; a=openpgp-sha256; l=2282; i=a.hindborg@kernel.org; h=from:subject:message-id; bh=LiaDRIukgxQ10jLoKnR7ZV1S7vIQx9wTW24ArpjaY5M=; b=owEBbQKS/ZANAwAIAeG4Gj55KGN3AcsmYgBomv8dOg+tWAebpOsOzOIbstCu7JSswO0iOdbYh ccMq+Xhv46JAjMEAAEIAB0WIQQSwflHVr98KhXWwBLhuBo+eShjdwUCaJr/HQAKCRDhuBo+eShj d06iD/9CMSzzqlw4Eya2xtHn6xJ1Yxa7LWvHaxBhAFlzr/L4YxubXJ8y+RphqtBnm2V3nSTJDPp 7/WtlyAWJ5wtWlUWEcelv7qDbHlBuV4YbeXTCu6BRS+mvU5qGJDWDCRFPb/tQM5mbUnCDfnVN2d NJk1s0HOmu1B9ZzyUbB6vUirmFbg4LEBCsdTeTNCx8bf5fj9YFtZ4DVgWwlRcFQh7Ohw4Bn5uhF KfKxSwXeUg7TLKt3TWGdbaN3IvhEOjzb8p9nPSDEkg8WtvhQTK8VK64OSB7UT/6I3DO2GszmvKY SFK4qrnEY2bJypNoFGRmlj7MlJPlw8lFVOzhtvePH5FzlG/Ajv5bOGFnPNbdzBWKKBwHPca1qSe Gtw7cVLIiBfQ6K7qT8yisf3UYJQHab1sdoUwv/20ppNLo/+VW9axNFy00Nf3KBt4xrxcbMPW0Kn g8lF/dFhfvcjHFEMtv+pgStQWReK9+hekwz3u2yd3nDA/lCZ3szOKNP33TDU/RfAzR3GJPA5NZm L3xzdgL+b9cEHJqWhIzmN5M9dWjEozOvp/BAwOChpZ1uHv9Lt6rAqYjh2dthN9m8v3e51G2q77S fyW6UrTrUmIQi+rl5tQa0kFUfxMbEnjMSmjWw5iH4il29C4qXNdoJ4Bm++RMNGxhaBzThb0Zbf3 NIDhPJjG8xR2+lw== X-Developer-Key: i=a.hindborg@kernel.org; a=openpgp; fpr=3108C10F46872E248D1FB221376EB100563EF7A7 Improve `Formatter` so that it can write to an array or slice buffer. Signed-off-by: Andreas Hindborg --- rust/kernel/str.rs | 23 +++++++++++++++++------ 1 file changed, 17 insertions(+), 6 deletions(-) diff --git a/rust/kernel/str.rs b/rust/kernel/str.rs index 082790b7a621..76632da357a6 100644 --- a/rust/kernel/str.rs +++ b/rust/kernel/str.rs @@ -7,7 +7,10 @@ fmt::{self, Write}, prelude::*, }; -use core::ops::{self, Deref, DerefMut, Index}; +use core::{ + marker::PhantomData, + ops::{self, Deref, DerefMut, Index}, +}; /// Byte string without UTF-8 validity guarantee. #[repr(transparent)] @@ -825,9 +828,9 @@ fn write_str(&mut self, s: &str) -> fmt::Result { /// Allows formatting of [`fmt::Arguments`] into a raw buffer. /// /// Fails if callers attempt to write more than will fit in the buffer. -pub(crate) struct Formatter(RawFormatter); +pub(crate) struct Formatter<'a>(RawFormatter, PhantomData<&'a mut ()>); -impl Formatter { +impl Formatter<'_> { /// Creates a new instance of [`Formatter`] with the given buffer. /// /// # Safety @@ -836,11 +839,19 @@ impl Formatter { /// for the lifetime of the returned [`Formatter`]. pub(crate) unsafe fn from_buffer(buf: *mut u8, len: usize) -> Self { // SAFETY: The safety requirements of this function satisfy those of the callee. - Self(unsafe { RawFormatter::from_buffer(buf, len) }) + Self(unsafe { RawFormatter::from_buffer(buf, len) }, PhantomData) + } + + /// Create a new [`Self`] instance. + #[expect(dead_code)] + pub(crate) fn new(buffer: &mut [u8]) -> Self { + // SAFETY: `buffer` is valid for writes for the entire length for + // the lifetime of `Self`. + unsafe { Formatter::from_buffer(buffer.as_mut_ptr(), buffer.len()) } } } -impl Deref for Formatter { +impl Deref for Formatter<'_> { type Target = RawFormatter; fn deref(&self) -> &Self::Target { @@ -848,7 +859,7 @@ fn deref(&self) -> &Self::Target { } } -impl fmt::Write for Formatter { +impl fmt::Write for Formatter<'_> { fn write_str(&mut self, s: &str) -> fmt::Result { self.0.write_str(s)?; -- 2.47.2