From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (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 23948135411 for ; Fri, 16 Feb 2024 17:11:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708103497; cv=none; b=bE0oGWHsXfn7TtEaqhVvOR+1Iw0KVpqviyl2sO+xnrM+BgKCTUcsviEJwhljYWhjCtz/V0skMUAPqnkFZI759Z4+ma3y6mMcmzoRMMx5rDnpBxHlmnsGzWGdGCRV5UvmBxYGQC93y7rBXwVqgUrOROSiAjDxFP55ejwvClnh704= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708103497; c=relaxed/simple; bh=JGNjC7+UwjY9T7LKlTiK6c8kteezBUyHZKMhIDM1Evg=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=m5FltuZtEgdSIYXIaXZrrAuRD7Udj3wfZVxJsMdtdPihGWifiqKMQR/pZAyvjzUMfCJytLUotC0rjG5A95Vkd5zit3GUDupxEbDAS1d1rrg5td9qHpREiDfhE5RsclHtyM3IY2Rt2ctLZOKRjzf6zfWCOohHhgaVR43k8OoWEjI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=C3gPGtm+; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="C3gPGtm+" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1708103495; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=MIijY/r8LLfMl6D20rFmwbeRhmzXm+JMQ2A7E38ejDY=; b=C3gPGtm+sb2FuixF0HaBMQzSDAHE+xXXnArPIEnRRH4+KtZGvRAcXZ06b0cZi2KeWCMC7x djQk8AhSnSM1RuHfG8oJHGaOwxviikfRWkxa4katVb3M/M35DvhDdHR2b9QOP/xTYsTO5C ovrMs0HyJIC0KQmEUKt+r3E+VtuzvnA= Received: from mail-ej1-f71.google.com (mail-ej1-f71.google.com [209.85.218.71]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-341-M2Rj73FvOBu5iOT_p3gnQg-1; Fri, 16 Feb 2024 12:11:33 -0500 X-MC-Unique: M2Rj73FvOBu5iOT_p3gnQg-1 Received: by mail-ej1-f71.google.com with SMTP id a640c23a62f3a-a35a649c608so129559466b.2 for ; Fri, 16 Feb 2024 09:11:33 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1708103492; x=1708708292; h=content-transfer-encoding:in-reply-to:organization:from:references :cc:to:content-language:subject:user-agent:mime-version:date :message-id:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=MIijY/r8LLfMl6D20rFmwbeRhmzXm+JMQ2A7E38ejDY=; b=ReUiIx6APPOviY53+G/kD/4vsz5sCBYK/LNJVqFuKNdWfmIIzqql1018MMwGVM2LkP DPvVDRh22ZpfR4/19fHwhpp2uHulsAPaAF3PHgUf0RZ95JBEWEG6xoOnk/XmHfUE97Fh aOt5yLwJoKwuTVaUH52uz9jeEuDYWG60+nPF8GkZP1XDOY5sH4CqRNWkp77z6gMOacLQ 0wH6GVHAlcDq9J8p+xo1O+XugFf3W4gwmTD+CKzQLyxgPYeogLkJY8ujW4XJKWNM3ITL Qxr3DsXiWRArNaiHF1uoELDDqnF+48oUB86YadcpByFGb6+5MTxCjxOzegyJlLjbziWQ lR6Q== X-Forwarded-Encrypted: i=1; AJvYcCXzFVF/n+jsxOhy0z5RxOufxMvEdcG8vWAOSi+Q4YyZqa+zWCA6AvYtoLd/Tug0YBjABp3Q7+dEf5BPcRDaaorK1ONTvuOTvgNxwIlt X-Gm-Message-State: AOJu0YwkWPx/QOYllp4cPf/fiEdtF2lesoYEcxuHcoBYwmBk/TLHO54c LYulZyHUkAijo8g88znVazMOKI2BJoTqVxvJ6rR1nhxGZhl4z7TKuMrjvPR/O1Pgr5n2c+xVIpG pRkY8UkivhD4Ql//g62ZaXQbkEavnxen0+o2e8lEK6zdxfo/sY8kccnEbqDV8jQ== X-Received: by 2002:a17:906:3bd8:b0:a3d:86c0:4689 with SMTP id v24-20020a1709063bd800b00a3d86c04689mr3695498ejf.32.1708103492550; Fri, 16 Feb 2024 09:11:32 -0800 (PST) X-Google-Smtp-Source: AGHT+IFpvQYv23/X9db3iCL0o1v5CbF+U8MTR/LKixroenoT99EeMYj3m5SvBXid/pIob2FHWV+Y1A== X-Received: by 2002:a17:906:3bd8:b0:a3d:86c0:4689 with SMTP id v24-20020a1709063bd800b00a3d86c04689mr3695480ejf.32.1708103492265; Fri, 16 Feb 2024 09:11:32 -0800 (PST) Received: from ?IPV6:2a02:810d:4b3f:ee94:abf:b8ff:feee:998b? ([2a02:810d:4b3f:ee94:abf:b8ff:feee:998b]) by smtp.gmail.com with ESMTPSA id v22-20020a1709061dd600b00a3d8fb05c0csm141614ejh.86.2024.02.16.09.11.31 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 16 Feb 2024 09:11:31 -0800 (PST) Message-ID: <18a49662-3640-49c1-9587-db5cc9d62fbc@redhat.com> Date: Fri, 16 Feb 2024 18:11:30 +0100 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3] rust: str: add {make,to}_{upper,lower}case() to CString Content-Language: en-US To: Alice Ryhl Cc: a.hindborg@samsung.com, alex.gaynor@gmail.com, benno.lossin@proton.me, bjorn3_gh@protonmail.com, boqun.feng@gmail.com, gary@garyguo.net, linux-kernel@vger.kernel.org, ojeda@kernel.org, rust-for-linux@vger.kernel.org, wedsonaf@gmail.com References: <20240214172505.5044-1-dakr@redhat.com> <20240216165320.1820346-1-aliceryhl@google.com> From: Danilo Krummrich Organization: RedHat In-Reply-To: <20240216165320.1820346-1-aliceryhl@google.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 2/16/24 17:53, Alice Ryhl wrote: >> + pub fn make_ascii_lowercase(&mut self) { >> + self.0.make_ascii_lowercase(); >> + } > > It's important to note here that this doesn't remove or introduce NUL > bytes. > > pub fn make_ascii_lowercase(&mut self) { > // INVARIANT: This doesn't introduce or remove NUL bytes in the c > // string. > self.0.make_ascii_lowercase(); > } > > Ditto for make_ascii_uppercase. (But not the to_* methods.) > >> + /// Returns a copy of this [`CString`] where each character is mapped to its >> + /// ASCII lower case equivalent. >> + /// >> + /// ASCII letters 'A' to 'Z' are mapped to 'a' to 'z', >> + /// but non-ASCII letters are unchanged. >> + /// >> + /// To lowercase the value in-place, use [`make_ascii_lowercase`]. >> + /// >> + /// [`make_ascii_lowercase`]: str::make_ascii_lowercase >> + pub fn to_ascii_lowercase(&self) -> Result { >> + let mut s = (*self).to_cstring()?; >> + >> + s.make_ascii_lowercase(); >> + >> + return Ok(s); >> + } >> + >> + /// Returns a copy of this [`CString`] where each character is mapped to its >> + /// ASCII upper case equivalent. >> + /// >> + /// ASCII letters 'a' to 'z' are mapped to 'A' to 'Z', >> + /// but non-ASCII letters are unchanged. >> + /// >> + /// To uppercase the value in-place, use [`make_ascii_uppercase`]. >> + /// >> + /// [`make_ascii_uppercase`]: str::make_ascii_uppercase >> + pub fn to_ascii_uppercase(&self) -> Result { >> + let mut s = (*self).to_cstring()?; >> + >> + s.make_ascii_uppercase(); >> + >> + return Ok(s); >> + } > > Please move these to `CStr` as well. That would result into two copies if I actually want a CString, wouldn't it? Also, what would be the use case? And even if someone wants to have a CStr again, couldn't we just deref the resulting CString? - Danilo > >> +impl DerefMut for CString { >> + fn deref_mut(&mut self) -> &mut Self::Target { >> + unsafe { CStr::from_bytes_with_nul_unchecked_mut(&mut *self.buf) } >> + } >> +} > > Needs a safety comment. > > impl DerefMut for CString { > fn deref_mut(&mut self) -> &mut Self::Target { > // SAFETY: A `CString` is always NUL-terminated and contains no > // other NUL bytes. > unsafe { CStr::from_bytes_with_nul_unchecked_mut(&mut *self.buf) } > } > } > > Alice >