1860ee521a
This commit is an implementation of [RFC 592][r592] and [RFC 840][r840]. These two RFCs tweak the behavior of `CString` and add a new `CStr` unsized slice type to the module. [r592]: https://github.com/rust-lang/rfcs/blob/master/text/0592-c-str-deref.md [r840]: https://github.com/rust-lang/rfcs/blob/master/text/0840-no-panic-in-c-string.md The new `CStr` type is only constructable via two methods: 1. By `deref`'ing from a `CString` 2. Unsafely via `CStr::from_ptr` The purpose of `CStr` is to be an unsized type which is a thin pointer to a `libc::c_char` (currently it is a fat pointer slice due to implementation limitations). Strings from C can be safely represented with a `CStr` and an appropriate lifetime as well. Consumers of `&CString` should now consume `&CStr` instead to allow producers to pass in C-originating strings instead of just Rust-allocated strings. A new constructor was added to `CString`, `new`, which takes `T: IntoBytes` instead of separate `from_slice` and `from_vec` methods (both have been deprecated in favor of `new`). The `new` method returns a `Result` instead of panicking. The error variant contains the relevant information about where the error happened and bytes (if present). Conversions are provided to the `io::Error` and `old_io::IoError` types via the `FromError` trait which translate to `InvalidInput`. This is a breaking change due to the modification of existing `#[unstable]` APIs and new deprecation, and more detailed information can be found in the two RFCs. Notable breakage includes: * All construction of `CString` now needs to use `new` and handle the outgoing `Result`. * Usage of `CString` as a byte slice now explicitly needs a `.as_bytes()` call. * The `as_slice*` methods have been removed in favor of just having the `as_bytes*` methods. Closes #22469 Closes #22470 [breaking-change]
37 lines
992 B
Rust
37 lines
992 B
Rust
// Copyright 2012 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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// ignore-fast doesn't like extern crate
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extern crate libc;
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use std::ffi::CString;
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mod mlibc {
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use libc::{c_char, size_t};
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extern {
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#[link_name = "strlen"]
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pub fn my_strlen(str: *const c_char) -> size_t;
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}
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}
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fn strlen(str: String) -> uint {
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// C string is terminated with a zero
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let s = CString::from_slice(str.as_bytes()).unwrap();
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unsafe {
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mlibc::my_strlen(s.as_ptr()) as uint
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}
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}
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pub fn main() {
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let len = strlen("Rust".to_string());
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assert_eq!(len, 4u);
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}
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