diff options
Diffstat (limited to 'library/std/src')
| -rw-r--r-- | library/std/src/error.rs | 43 | ||||
| -rw-r--r-- | library/std/src/ffi/c_str.rs | 1680 | ||||
| -rw-r--r-- | library/std/src/ffi/c_str/tests.rs | 240 | ||||
| -rw-r--r-- | library/std/src/ffi/mod.rs | 11 | ||||
| -rw-r--r-- | library/std/src/lib.rs | 2 | ||||
| -rw-r--r-- | library/std/src/prelude/v1.rs | 4 |
6 files changed, 55 insertions, 1925 deletions
diff --git a/library/std/src/error.rs b/library/std/src/error.rs index 4fb94908c80..3f85c2095cb 100644 --- a/library/std/src/error.rs +++ b/library/std/src/error.rs @@ -26,6 +26,7 @@ use crate::borrow::Cow; use crate::cell; use crate::char; use crate::fmt::{self, Debug, Display, Write}; +use crate::io; use crate::mem::transmute; use crate::num; use crate::str; @@ -612,6 +613,48 @@ impl Error for alloc::collections::TryReserveError {} #[unstable(feature = "duration_checked_float", issue = "83400")] impl Error for time::FromFloatSecsError {} +#[stable(feature = "rust1", since = "1.0.0")] +impl Error for alloc::ffi::NulError { + #[allow(deprecated)] + fn description(&self) -> &str { + "nul byte found in data" + } +} + +#[stable(feature = "rust1", since = "1.0.0")] +impl From<alloc::ffi::NulError> for io::Error { + /// Converts a [`alloc::ffi::NulError`] into a [`io::Error`]. + fn from(_: alloc::ffi::NulError) -> io::Error { + io::const_io_error!(io::ErrorKind::InvalidInput, "data provided contains a nul byte") + } +} + +#[stable(feature = "frombyteswithnulerror_impls", since = "1.17.0")] +impl Error for core::ffi::FromBytesWithNulError { + #[allow(deprecated)] + fn description(&self) -> &str { + self.__description() + } +} + +#[unstable(feature = "cstr_from_bytes_until_nul", issue = "95027")] +impl Error for core::ffi::FromBytesUntilNulError {} + +#[stable(feature = "cstring_from_vec_with_nul", since = "1.58.0")] +impl Error for alloc::ffi::FromVecWithNulError {} + +#[stable(feature = "cstring_into", since = "1.7.0")] +impl Error for alloc::ffi::IntoStringError { + #[allow(deprecated)] + fn description(&self) -> &str { + "C string contained non-utf8 bytes" + } + + fn source(&self) -> Option<&(dyn Error + 'static)> { + Some(self.__source()) + } +} + // Copied from `any.rs`. impl dyn Error + 'static { /// Returns `true` if the inner type is the same as `T`. diff --git a/library/std/src/ffi/c_str.rs b/library/std/src/ffi/c_str.rs deleted file mode 100644 index a68def1e83d..00000000000 --- a/library/std/src/ffi/c_str.rs +++ /dev/null @@ -1,1680 +0,0 @@ -#![deny(unsafe_op_in_unsafe_fn)] - -#[cfg(test)] -mod tests; - -use crate::ascii; -use crate::borrow::{Borrow, Cow}; -use crate::cmp::Ordering; -use crate::error::Error; -use crate::fmt::{self, Write}; -use crate::io; -use crate::mem; -use crate::num::NonZeroU8; -use crate::ops; -use crate::os::raw::c_char; -use crate::ptr; -use crate::rc::Rc; -use crate::slice; -use crate::str::{self, Utf8Error}; -use crate::sync::Arc; -use crate::sys; -use crate::sys_common::memchr; - -/// A type representing an owned, C-compatible, nul-terminated string with no nul bytes in the -/// middle. -/// -/// This type serves the purpose of being able to safely generate a -/// C-compatible string from a Rust byte slice or vector. An instance of this -/// type is a static guarantee that the underlying bytes contain no interior 0 -/// bytes ("nul characters") and that the final byte is 0 ("nul terminator"). -/// -/// `CString` is to <code>&[CStr]</code> as [`String`] is to <code>&[str]</code>: the former -/// in each pair are owned strings; the latter are borrowed -/// references. -/// -/// # Creating a `CString` -/// -/// A `CString` is created from either a byte slice or a byte vector, -/// or anything that implements <code>[Into]<[Vec]<[u8]>></code> (for -/// example, you can build a `CString` straight out of a [`String`] or -/// a <code>&[str]</code>, since both implement that trait). -/// -/// The [`CString::new`] method will actually check that the provided <code>&[[u8]]</code> -/// does not have 0 bytes in the middle, and return an error if it -/// finds one. -/// -/// # Extracting a raw pointer to the whole C string -/// -/// `CString` implements an [`as_ptr`][`CStr::as_ptr`] method through the [`Deref`] -/// trait. This method will give you a `*const c_char` which you can -/// feed directly to extern functions that expect a nul-terminated -/// string, like C's `strdup()`. Notice that [`as_ptr`][`CStr::as_ptr`] returns a -/// read-only pointer; if the C code writes to it, that causes -/// undefined behavior. -/// -/// # Extracting a slice of the whole C string -/// -/// Alternatively, you can obtain a <code>&[[u8]]</code> slice from a -/// `CString` with the [`CString::as_bytes`] method. Slices produced in this -/// way do *not* contain the trailing nul terminator. This is useful -/// when you will be calling an extern function that takes a `*const -/// u8` argument which is not necessarily nul-terminated, plus another -/// argument with the length of the string — like C's `strndup()`. -/// You can of course get the slice's length with its -/// [`len`][slice::len] method. -/// -/// If you need a <code>&[[u8]]</code> slice *with* the nul terminator, you -/// can use [`CString::as_bytes_with_nul`] instead. -/// -/// Once you have the kind of slice you need (with or without a nul -/// terminator), you can call the slice's own -/// [`as_ptr`][slice::as_ptr] method to get a read-only raw pointer to pass to -/// extern functions. See the documentation for that function for a -/// discussion on ensuring the lifetime of the raw pointer. -/// -/// [str]: prim@str "str" -/// [`Deref`]: ops::Deref -/// -/// # Examples -/// -/// ```ignore (extern-declaration) -/// # fn main() { -/// use std::ffi::CString; -/// use std::os::raw::c_char; -/// -/// extern "C" { -/// fn my_printer(s: *const c_char); -/// } -/// -/// // We are certain that our string doesn't have 0 bytes in the middle, -/// // so we can .expect() -/// let c_to_print = CString::new("Hello, world!").expect("CString::new failed"); -/// unsafe { -/// my_printer(c_to_print.as_ptr()); -/// } -/// # } -/// ``` -/// -/// # Safety -/// -/// `CString` is intended for working with traditional C-style strings -/// (a sequence of non-nul bytes terminated by a single nul byte); the -/// primary use case for these kinds of strings is interoperating with C-like -/// code. Often you will need to transfer ownership to/from that external -/// code. It is strongly recommended that you thoroughly read through the -/// documentation of `CString` before use, as improper ownership management -/// of `CString` instances can lead to invalid memory accesses, memory leaks, -/// and other memory errors. -#[derive(PartialEq, PartialOrd, Eq, Ord, Hash, Clone)] -#[cfg_attr(not(test), rustc_diagnostic_item = "cstring_type")] -#[stable(feature = "rust1", since = "1.0.0")] -pub struct CString { - // Invariant 1: the slice ends with a zero byte and has a length of at least one. - // Invariant 2: the slice contains only one zero byte. - // Improper usage of unsafe function can break Invariant 2, but not Invariant 1. - inner: Box<[u8]>, -} - -/// Representation of a borrowed C string. -/// -/// This type represents a borrowed reference to a nul-terminated -/// array of bytes. It can be constructed safely from a <code>&[[u8]]</code> -/// slice, or unsafely from a raw `*const c_char`. It can then be -/// converted to a Rust <code>&[str]</code> by performing UTF-8 validation, or -/// into an owned [`CString`]. -/// -/// `&CStr` is to [`CString`] as <code>&[str]</code> is to [`String`]: the former -/// in each pair are borrowed references; the latter are owned -/// strings. -/// -/// Note that this structure is **not** `repr(C)` and is not recommended to be -/// placed in the signatures of FFI functions. Instead, safe wrappers of FFI -/// functions may leverage the unsafe [`CStr::from_ptr`] constructor to provide -/// a safe interface to other consumers. -/// -/// # Examples -/// -/// Inspecting a foreign C string: -/// -/// ```ignore (extern-declaration) -/// use std::ffi::CStr; -/// use std::os::raw::c_char; -/// -/// extern "C" { fn my_string() -> *const c_char; } -/// -/// unsafe { -/// let slice = CStr::from_ptr(my_string()); -/// println!("string buffer size without nul terminator: {}", slice.to_bytes().len()); -/// } -/// ``` -/// -/// Passing a Rust-originating C string: -/// -/// ```ignore (extern-declaration) -/// use std::ffi::{CString, CStr}; -/// use std::os::raw::c_char; -/// -/// fn work(data: &CStr) { -/// extern "C" { fn work_with(data: *const c_char); } -/// -/// unsafe { work_with(data.as_ptr()) } -/// } -/// -/// let s = CString::new("data data data data").expect("CString::new failed"); -/// work(&s); -/// ``` -/// -/// Converting a foreign C string into a Rust [`String`]: -/// -/// ```ignore (extern-declaration) -/// use std::ffi::CStr; -/// use std::os::raw::c_char; -/// -/// extern "C" { fn my_string() -> *const c_char; } -/// -/// fn my_string_safe() -> String { -/// unsafe { -/// CStr::from_ptr(my_string()).to_string_lossy().into_owned() -/// } -/// } -/// -/// println!("string: {}", my_string_safe()); -/// ``` -/// -/// [str]: prim@str "str" -#[derive(Hash)] -#[cfg_attr(not(test), rustc_diagnostic_item = "CStr")] -#[stable(feature = "rust1", since = "1.0.0")] -// FIXME: -// `fn from` in `impl From<&CStr> for Box<CStr>` current implementation relies -// on `CStr` being layout-compatible with `[u8]`. -// When attribute privacy is implemented, `CStr` should be annotated as `#[repr(transparent)]`. -// Anyway, `CStr` representation and layout are considered implementation detail, are -// not documented and must not be relied upon. -pub struct CStr { - // FIXME: this should not be represented with a DST slice but rather with - // just a raw `c_char` along with some form of marker to make - // this an unsized type. Essentially `sizeof(&CStr)` should be the - // same as `sizeof(&c_char)` but `CStr` should be an unsized type. - inner: [c_char], -} - -/// An error indicating that an interior nul byte was found. -/// -/// While Rust strings may contain nul bytes in the middle, C strings -/// can't, as that byte would effectively truncate the string. -/// -/// This error is created by the [`new`][`CString::new`] method on -/// [`CString`]. See its documentation for more. -/// -/// # Examples -/// -/// ``` -/// use std::ffi::{CString, NulError}; -/// -/// let _: NulError = CString::new(b"f\0oo".to_vec()).unwrap_err(); -/// ``` -#[derive(Clone, PartialEq, Eq, Debug)] -#[stable(feature = "rust1", since = "1.0.0")] -pub struct NulError(usize, Vec<u8>); - -/// An error indicating that a nul byte was not in the expected position. -/// -/// The slice used to create a [`CStr`] must have one and only one nul byte, -/// positioned at the end. -/// -/// This error is created by the [`CStr::from_bytes_with_nul`] method. -/// See its documentation for more. -/// -/// # Examples -/// -/// ``` -/// use std::ffi::{CStr, FromBytesWithNulError}; -/// -/// let _: FromBytesWithNulError = CStr::from_bytes_with_nul(b"f\0oo").unwrap_err(); -/// ``` -#[derive(Clone, PartialEq, Eq, Debug)] -#[stable(feature = "cstr_from_bytes", since = "1.10.0")] -pub struct FromBytesWithNulError { - kind: FromBytesWithNulErrorKind, -} - -/// An error indicating that a nul byte was not in the expected position. -/// -/// The vector used to create a [`CString`] must have one and only one nul byte, -/// positioned at the end. -/// -/// This error is created by the [`CString::from_vec_with_nul`] method. -/// See its documentation for more. -/// -/// # Examples -/// -/// ``` -/// use std::ffi::{CString, FromVecWithNulError}; -/// -/// let _: FromVecWithNulError = CString::from_vec_with_nul(b"f\0oo".to_vec()).unwrap_err(); -/// ``` -#[derive(Clone, PartialEq, Eq, Debug)] -#[stable(feature = "cstring_from_vec_with_nul", since = "1.58.0")] -pub struct FromVecWithNulError { - error_kind: FromBytesWithNulErrorKind, - bytes: Vec<u8>, -} - -#[derive(Clone, PartialEq, Eq, Debug)] -enum FromBytesWithNulErrorKind { - InteriorNul(usize), - NotNulTerminated, -} - -impl FromBytesWithNulError { - fn interior_nul(pos: usize) -> FromBytesWithNulError { - FromBytesWithNulError { kind: FromBytesWithNulErrorKind::InteriorNul(pos) } - } - fn not_nul_terminated() -> FromBytesWithNulError { - FromBytesWithNulError { kind: FromBytesWithNulErrorKind::NotNulTerminated } - } -} - -#[stable(feature = "cstring_from_vec_with_nul", since = "1.58.0")] -impl FromVecWithNulError { - /// Returns a slice of [`u8`]s bytes that were attempted to convert to a [`CString`]. - /// - /// # Examples - /// - /// Basic usage: - /// - /// ``` - /// use std::ffi::CString; - /// - /// // Some invalid bytes in a vector - /// let bytes = b"f\0oo".to_vec(); - /// - /// let value = CString::from_vec_with_nul(bytes.clone()); - /// - /// assert_eq!(&bytes[..], value.unwrap_err().as_bytes()); - /// ``` - #[must_use] - #[stable(feature = "cstring_from_vec_with_nul", since = "1.58.0")] - pub fn as_bytes(&self) -> &[u8] { - &self.bytes[..] - } - - /// Returns the bytes that were attempted to convert to a [`CString`]. - /// - /// This method is carefully constructed to avoid allocation. It will - /// consume the error, moving out the bytes, so that a copy of the bytes - /// does not need to be made. - /// - /// # Examples - /// - /// Basic usage: - /// - /// ``` - /// use std::ffi::CString; - /// - /// // Some invalid bytes in a vector - /// let bytes = b"f\0oo".to_vec(); - /// - /// let value = CString::from_vec_with_nul(bytes.clone()); - /// - /// assert_eq!(bytes, value.unwrap_err().into_bytes()); - /// ``` - #[must_use = "`self` will be dropped if the result is not used"] - #[stable(feature = "cstring_from_vec_with_nul", since = "1.58.0")] - pub fn into_bytes(self) -> Vec<u8> { - self.bytes - } -} - -/// An error indicating that no nul byte was present. -/// -/// A slice used to create a [`CStr`] must contain a nul byte somewhere -/// within the slice. -/// -/// This error is created by the [`CStr::from_bytes_until_nul`] method. -/// -#[derive(Clone, PartialEq, Eq, Debug)] -#[unstable(feature = "cstr_from_bytes_until_nul", issue = "95027")] -pub struct FromBytesUntilNulError(()); - -#[unstable(feature = "cstr_from_bytes_until_nul", issue = "95027")] -impl Error for FromBytesUntilNulError {} - -#[unstable(feature = "cstr_from_bytes_until_nul", issue = "95027")] -impl fmt::Display for FromBytesUntilNulError { - fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { - write!(f, "data provided does not contain a nul") - } -} - -/// An error indicating invalid UTF-8 when converting a [`CString`] into a [`String`]. -/// -/// `CString` is just a wrapper over a buffer of bytes with a nul terminator; -/// [`CString::into_string`] performs UTF-8 validation on those bytes and may -/// return this error. -/// -/// This `struct` is created by [`CString::into_string()`]. See -/// its documentation for more. -#[derive(Clone, PartialEq, Eq, Debug)] -#[stable(feature = "cstring_into", since = "1.7.0")] -pub struct IntoStringError { - inner: CString, - error: Utf8Error, -} - -impl CString { - /// Creates a new C-compatible string from a container of bytes. - /// - /// This function will consume the provided data and use the - /// underlying bytes to construct a new string, ensuring that - /// there is a trailing 0 byte. This trailing 0 byte will be - /// appended by this function; the provided data should *not* - /// contain any 0 bytes in it. - /// - /// # Examples - /// - /// ```ignore (extern-declaration) - /// use std::ffi::CString; - /// use std::os::raw::c_char; - /// - /// extern "C" { fn puts(s: *const c_char); } - /// - /// let to_print = CString::new("Hello!").expect("CString::new failed"); - /// unsafe { - /// puts(to_print.as_ptr()); - /// } - /// ``` - /// - /// # Errors - /// - /// This function will return an error if the supplied bytes contain an - /// internal 0 byte. The [`NulError`] returned will contain the bytes as well as - /// the position of the nul byte. - #[stable(feature = "rust1", since = "1.0.0")] - pub fn new<T: Into<Vec<u8>>>(t: T) -> Result<CString, NulError> { - trait SpecNewImpl { - fn spec_new_impl(self) -> Result<CString, NulError>; - } - - impl<T: Into<Vec<u8>>> SpecNewImpl for T { - default fn spec_new_impl(self) -> Result<CString, NulError> { - let bytes: Vec<u8> = self.into(); - match memchr::memchr(0, &bytes) { - Some(i) => Err(NulError(i, bytes)), - None => Ok(unsafe { CString::_from_vec_unchecked(bytes) }), - } - } - } - - // Specialization for avoiding reallocation - #[inline(always)] // Without that it is not inlined into specializations - fn spec_new_impl_bytes(bytes: &[u8]) -> Result<CString, NulError> { - // We cannot have such large slice that we would overflow here - // but using `checked_add` allows LLVM to assume that capacity never overflows - // and generate twice shorter code. - // `saturating_add` doesn't help for some reason. - let capacity = bytes.len().checked_add(1).unwrap(); - - // Allocate before validation to avoid duplication of allocation code. - // We still need to allocate and copy memory even if we get an error. - let mut buffer = Vec::with_capacity(capacity); - buffer.extend(bytes); - - // Check memory of self instead of new buffer. - // This allows better optimizations if lto enabled. - match memchr::memchr(0, bytes) { - Some(i) => Err(NulError(i, buffer)), - None => Ok(unsafe { CString::_from_vec_unchecked(buffer) }), - } - } - - impl SpecNewImpl for &'_ [u8] { - fn spec_new_impl(self) -> Result<CString, NulError> { - spec_new_impl_bytes(self) - } - } - - impl SpecNewImpl for &'_ str { - fn spec_new_impl(self) -> Result<CString, NulError> { - spec_new_impl_bytes(self.as_bytes()) - } - } - - impl SpecNewImpl for &'_ mut [u8] { - fn spec_new_impl(self) -> Result<CString, NulError> { - spec_new_impl_bytes(self) - } - } - - t.spec_new_impl() - } - - /// Creates a C-compatible string by consuming a byte vector, - /// without checking for interior 0 bytes. - /// - /// Trailing 0 byte will be appended by this function. - /// - /// This method is equivalent to [`CString::new`] except that no runtime - /// assertion is made that `v` contains no 0 bytes, and it requires an - /// actual byte vector, not anything that can be converted to one with Into. - /// - /// # Examples - /// - /// ``` - /// use std::ffi::CString; - /// - /// let raw = b"foo".to_vec(); - /// unsafe { - /// let c_string = CString::from_vec_unchecked(raw); - /// } - /// ``` - #[must_use] - #[stable(feature = "rust1", since = "1.0.0")] - pub unsafe fn from_vec_unchecked(v: Vec<u8>) -> Self { - debug_assert!(memchr::memchr(0, &v).is_none()); - unsafe { Self::_from_vec_unchecked(v) } - } - - unsafe fn _from_vec_unchecked(mut v: Vec<u8>) -> Self { - v.reserve_exact(1); - v.push(0); - Self { inner: v.into_boxed_slice() } - } - - /// Retakes ownership of a `CString` that was transferred to C via - /// [`CString::into_raw`]. - /// - /// Additionally, the length of the string will be recalculated from the pointer. - /// - /// # Safety - /// - /// This should only ever be called with a pointer that was earlier - /// obtained by calling [`CString::into_raw`]. Other usage (e.g., trying to take - /// ownership of a string that was allocated by foreign code) is likely to lead - /// to undefined behavior or allocator corruption. - /// - /// It should be noted that the length isn't just "recomputed," but that - /// the recomputed length must match the original length from the - /// [`CString::into_raw`] call. This means the [`CString::into_raw`]/`from_raw` - /// methods should not be used when passing the string to C functions that can - /// modify the string's length. - /// - /// > **Note:** If you need to borrow a string that was allocated by - /// > foreign code, use [`CStr`]. If you need to take ownership of - /// > a string that was allocated by foreign code, you will need to - /// > make your own provisions for freeing it appropriately, likely - /// > with the foreign code's API to do that. - /// - /// # Examples - /// - /// Creates a `CString`, pass ownership to an `extern` function (via raw pointer), then retake - /// ownership with `from_raw`: - /// - /// ```ignore (extern-declaration) - /// use std::ffi::CString; - /// use std::os::raw::c_char; - /// - /// extern "C" { - /// fn some_extern_function(s: *mut c_char); - /// } - /// - /// let c_string = CString::new("Hello!").expect("CString::new failed"); - /// let raw = c_string.into_raw(); - /// unsafe { - /// some_extern_function(raw); - /// let c_string = CString::from_raw(raw); - /// } - /// ``` - #[must_use = "call `drop(from_raw(ptr))` if you intend to drop the `CString`"] - #[stable(feature = "cstr_memory", since = "1.4.0")] - pub unsafe fn from_raw(ptr: *mut c_char) -> CString { - // SAFETY: This is called with a pointer that was obtained from a call - // to `CString::into_raw` and the length has not been modified. As such, - // we know there is a NUL byte (and only one) at the end and that the - // information about the size of the allocation is correct on Rust's - // side. - unsafe { - let len = sys::strlen(ptr) + 1; // Including the NUL byte - let slice = slice::from_raw_parts_mut(ptr, len as usize); - CString { inner: Box::from_raw(slice as *mut [c_char] as *mut [u8]) } - } - } - - /// Consumes the `CString` and transfers ownership of the string to a C caller. - /// - /// The pointer which this function returns must be returned to Rust and reconstituted using - /// [`CString::from_raw`] to be properly deallocated. Specifically, one - /// should *not* use the standard C `free()` function to deallocate - /// this string. - /// - /// Failure to call [`CString::from_raw`] will lead to a memory leak. - /// - /// The C side must **not** modify the length of the string (by writing a - /// `null` somewhere inside the string or removing the final one) before - /// it makes it back into Rust using [`CString::from_raw`]. See the safety section - /// in [`CString::from_raw`]. - /// - /// # Examples - /// - /// ``` - /// use std::ffi::CString; - /// - /// let c_string = CString::new("foo").expect("CString::new failed"); - /// - /// let ptr = c_string.into_raw(); - /// - /// unsafe { - /// assert_eq!(b'f', *ptr as u8); - /// assert_eq!(b'o', *ptr.offset(1) as u8); - /// assert_eq!(b'o', *ptr.offset(2) as u8); - /// assert_eq!(b'\0', *ptr.offset(3) as u8); - /// - /// // retake pointer to free memory - /// let _ = CString::from_raw(ptr); - /// } - /// ``` - #[inline] - #[must_use = "`self` will be dropped if the result is not used"] - #[stable(feature = "cstr_memory", since = "1.4.0")] - pub fn into_raw(self) -> *mut c_char { - Box::into_raw(self.into_inner()) as *mut c_char - } - - /// Converts the `CString` into a [`String`] if it contains valid UTF-8 data. - /// - /// On failure, ownership of the original `CString` is returned. - /// - /// # Examples - /// - /// ``` - /// use std::ffi::CString; - /// - /// let valid_utf8 = vec![b'f', b'o', b'o']; - /// let cstring = CString::new(valid_utf8).expect("CString::new failed"); - /// assert_eq!(cstring.into_string().expect("into_string() call failed"), "foo"); - /// - /// let invalid_utf8 = vec![b'f', 0xff, b'o', b'o']; - /// let cstring = CString::new(invalid_utf8).expect("CString::new failed"); - /// let err = cstring.into_string().err().expect("into_string().err() failed"); - /// assert_eq!(err.utf8_error().valid_up_to(), 1); - /// ``` - #[stable(feature = "cstring_into", since = "1.7.0")] - pub fn into_string(self) -> Result<String, IntoStringError> { - String::from_utf8(self.into_bytes()).map_err(|e| IntoStringError { - error: e.utf8_error(), - inner: unsafe { Self::_from_vec_unchecked(e.into_bytes()) }, - }) - } - - /// Consumes the `CString` and returns the underlying byte buffer. - /// - /// The returned buffer does **not** contain the trailing nul - /// terminator, and it is guaranteed to not have any interior nul - /// bytes. - /// - /// # Examples - /// - /// ``` - /// use std::ffi::CString; - /// - /// let c_string = CString::new("foo").expect("CString::new failed"); - /// let bytes = c_string.into_bytes(); - /// assert_eq!(bytes, vec![b'f', b'o', b'o']); - /// ``` - #[must_use = "`self` will be dropped if the result is not used"] - #[stable(feature = "cstring_into", since = "1.7.0")] - pub fn into_bytes(self) -> Vec<u8> { - let mut vec = self.into_inner().into_vec(); - let _nul = vec.pop(); - debug_assert_eq!(_nul, Some(0u8)); - vec - } - - /// Equivalent to [`CString::into_bytes()`] except that the - /// returned vector includes the trailing nul terminator. - /// - /// # Examples - /// - /// ``` - /// use std::ffi::CString; - /// - /// let c_string = CString::new("foo").expect("CString::new failed"); - /// let bytes = c_string.into_bytes_with_nul(); - /// assert_eq!(bytes, vec![b'f', b'o', b'o', b'\0']); - /// ``` - #[must_use = "`self` will be dropped if the result is not used"] - #[stable(feature = "cstring_into", since = "1.7.0")] - pub fn into_bytes_with_nul(self) -> Vec<u8> { - self.into_inner().into_vec() - } - - /// Returns the contents of this `CString` as a slice of bytes. - /// - /// The returned slice does **not** contain the trailing nul - /// terminator, and it is guaranteed to not have any interior nul - /// bytes. If you need the nul terminator, use - /// [`CString::as_bytes_with_nul`] instead. - /// - /// # Examples - /// - /// ``` - /// use std::ffi::CString; - /// - /// let c_string = CString::new("foo").expect("CString::new failed"); - /// let bytes = c_string.as_bytes(); - /// assert_eq!(bytes, &[b'f', b'o', b'o']); - /// ``` - #[inline] - #[must_use] - #[stable(feature = "rust1", since = "1.0.0")] - pub fn as_bytes(&self) -> &[u8] { - // SAFETY: CString has a length at least 1 - unsafe { self.inner.get_unchecked(..self.inner.len() - 1) } - } - - /// Equivalent to [`CString::as_bytes()`] except that the - /// returned slice includes the trailing nul terminator. - /// - /// # Examples - /// - /// ``` - /// use std::ffi::CString; - /// - /// let c_string = CString::new("foo").expect("CString::new failed"); - /// let bytes = c_string.as_bytes_with_nul(); - /// assert_eq!(bytes, &[b'f', b'o', b'o', b'\0']); - /// ``` - #[inline] - #[must_use] - #[stable(feature = "rust1", since = "1.0.0")] - pub fn as_bytes_with_nul(&self) -> &[u8] { - &self.inner - } - - /// Extracts a [`CStr`] slice containing the entire string. - /// - /// # Examples - /// - /// ``` - /// use std::ffi::{CString, CStr}; - /// - /// let c_string = CString::new(b"foo".to_vec()).expect("CString::new failed"); - /// let cstr = c_string.as_c_str(); - /// assert_eq!(cstr, - /// CStr::from_bytes_with_nul(b"foo\0").expect("CStr::from_bytes_with_nul failed")); - /// ``` - #[inline] - #[must_use] - #[stable(feature = "as_c_str", since = "1.20.0")] - pub fn as_c_str(&self) -> &CStr { - &*self - } - - /// Converts this `CString` into a boxed [`CStr`]. - /// - /// # Examples - /// - /// ``` - /// use std::ffi::{CString, CStr}; - /// - /// let c_string = CString::new(b"foo".to_vec()).expect("CString::new failed"); - /// let boxed = c_string.into_boxed_c_str(); - /// assert_eq!(&*boxed, - /// CStr::from_bytes_with_nul(b"foo\0").expect("CStr::from_bytes_with_nul failed")); - /// ``` - #[must_use = "`self` will be dropped if the result is not used"] - #[stable(feature = "into_boxed_c_str", since = "1.20.0")] - pub fn into_boxed_c_str(self) -> Box<CStr> { - unsafe { Box::from_raw(Box::into_raw(self.into_inner()) as *mut CStr) } - } - - /// Bypass "move out of struct which implements [`Drop`] trait" restriction. - #[inline] - fn into_inner(self) -> Box<[u8]> { - // Rationale: `mem::forget(self)` invalidates the previous call to `ptr::read(&self.inner)` - // so we use `ManuallyDrop` to ensure `self` is not dropped. - // Then we can return the box directly without invalidating it. - // See https://github.com/rust-lang/rust/issues/62553. - let this = mem::ManuallyDrop::new(self); - unsafe { ptr::read(&this.inner) } - } - - /// Converts a <code>[Vec]<[u8]></code> to a [`CString`] without checking the - /// invariants on the given [`Vec`]. - /// - /// # Safety - /// - /// The given [`Vec`] **must** have one nul byte as its last element. - /// This means it cannot be empty nor have any other nul byte anywhere else. - /// - /// # Example - /// - /// ``` - /// use std::ffi::CString; - /// assert_eq!( - /// unsafe { CString::from_vec_with_nul_unchecked(b"abc\0".to_vec()) }, - /// unsafe { CString::from_vec_unchecked(b"abc".to_vec()) } - /// ); - /// ``` - #[must_use] - #[stable(feature = "cstring_from_vec_with_nul", since = "1.58.0")] - pub unsafe fn from_vec_with_nul_unchecked(v: Vec<u8>) -> Self { - debug_assert!(memchr::memchr(0, &v).unwrap() + 1 == v.len()); - unsafe { Self::_from_vec_with_nul_unchecked(v) } - } - - unsafe fn _from_vec_with_nul_unchecked(v: Vec<u8>) -> Self { - Self { inner: v.into_boxed_slice() } - } - - /// Attempts to converts a <code>[Vec]<[u8]></code> to a [`CString`]. - /// - /// Runtime checks are present to ensure there is only one nul byte in the - /// [`Vec`], its last element. - /// - /// # Errors - /// - /// If a nul byte is present and not the last element or no nul bytes - /// is present, an error will be returned. - /// - /// # Examples - /// - /// A successful conversion will produce the same result as [`CString::new`] - /// when called without the ending nul byte. - /// - /// ``` - /// use std::ffi::CString; - /// assert_eq!( - /// CString::from_vec_with_nul(b"abc\0".to_vec()) - /// .expect("CString::from_vec_with_nul failed"), - /// CString::new(b"abc".to_vec()).expect("CString::new failed") - /// ); - /// ``` - /// - /// An incorrectly formatted [`Vec`] will produce an error. - /// - /// ``` - /// use std::ffi::{CString, FromVecWithNulError}; - /// // Interior nul byte - /// let _: FromVecWithNulError = CString::from_vec_with_nul(b"a\0bc".to_vec()).unwrap_err(); - /// // No nul byte - /// let _: FromVecWithNulError = CString::from_vec_with_nul(b"abc".to_vec()).unwrap_err(); - /// ``` - #[stable(feature = "cstring_from_vec_with_nul", since = "1.58.0")] - pub fn from_vec_with_nul(v: Vec<u8>) -> Result<Self, FromVecWithNulError> { - let nul_pos = memchr::memchr(0, &v); - match nul_pos { - Some(nul_pos) if nul_pos + 1 == v.len() => { - // SAFETY: We know there is only one nul byte, at the end - // of the vec. - Ok(unsafe { Self::_from_vec_with_nul_unchecked(v) }) - } - Some(nul_pos) => Err(FromVecWithNulError { - error_kind: FromBytesWithNulErrorKind::InteriorNul(nul_pos), - bytes: v, - }), - None => Err(FromVecWithNulError { - error_kind: FromBytesWithNulErrorKind::NotNulTerminated, - bytes: v, - }), - } - } -} - -// Turns this `CString` into an empty string to prevent -// memory-unsafe code from working by accident. Inline -// to prevent LLVM from optimizing it away in debug builds. -#[stable(feature = "cstring_drop", since = "1.13.0")] -impl Drop for CString { - #[inline] - fn drop(&mut self) { - unsafe { - *self.inner.get_unchecked_mut(0) = 0; - } - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl ops::Deref for CString { - type Target = CStr; - - #[inline] - fn deref(&self) -> &CStr { - unsafe { CStr::_from_bytes_with_nul_unchecked(self.as_bytes_with_nul()) } - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl fmt::Debug for CString { - fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { - fmt::Debug::fmt(&**self, f) - } -} - -#[stable(feature = "cstring_into", since = "1.7.0")] -impl From<CString> for Vec<u8> { - /// Converts a [`CString`] into a <code>[Vec]<[u8]></code>. - /// - /// The conversion consumes the [`CString`], and removes the terminating NUL byte. - #[inline] - fn from(s: CString) -> Vec<u8> { - s.into_bytes() - } -} - -#[stable(feature = "cstr_debug", since = "1.3.0")] -impl fmt::Debug for CStr { - fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { - write!(f, "\"")?; - for byte in self.to_bytes().iter().flat_map(|&b| ascii::escape_default(b)) { - f.write_char(byte as char)?; - } - write!(f, "\"") - } -} - -#[stable(feature = "cstr_default", since = "1.10.0")] -impl Default for &CStr { - fn default() -> Self { - const SLICE: &[c_char] = &[0]; - unsafe { CStr::from_ptr(SLICE.as_ptr()) } - } -} - -#[stable(feature = "cstr_default", since = "1.10.0")] -impl Default for CString { - /// Creates an empty `CString`. - fn default() -> CString { - let a: &CStr = Default::default(); - a.to_owned() - } -} - -#[stable(feature = "cstr_borrow", since = "1.3.0")] -impl Borrow<CStr> for CString { - #[inline] - fn borrow(&self) -> &CStr { - self - } -} - -#[stable(feature = "cstring_from_cow_cstr", since = "1.28.0")] -impl<'a> From<Cow<'a, CStr>> for CString { - /// Converts a `Cow<'a, CStr>` into a `CString`, by copying the contents if they are - /// borrowed. - #[inline] - fn from(s: Cow<'a, CStr>) -> Self { - s.into_owned() - } -} - -#[stable(feature = "box_from_c_str", since = "1.17.0")] -impl From<&CStr> for Box<CStr> { - /// Converts a `&CStr` into a `Box<CStr>`, - /// by copying the contents into a newly allocated [`Box`]. - fn from(s: &CStr) -> Box<CStr> { - let boxed: Box<[u8]> = Box::from(s.to_bytes_with_nul()); - unsafe { Box::from_raw(Box::into_raw(boxed) as *mut CStr) } - } -} - -#[stable(feature = "box_from_cow", since = "1.45.0")] -impl From<Cow<'_, CStr>> for Box<CStr> { - /// Converts a `Cow<'a, CStr>` into a `Box<CStr>`, - /// by copying the contents if they are borrowed. - #[inline] - fn from(cow: Cow<'_, CStr>) -> Box<CStr> { - match cow { - Cow::Borrowed(s) => Box::from(s), - Cow::Owned(s) => Box::from(s), - } - } -} - -#[stable(feature = "c_string_from_box", since = "1.18.0")] -impl From<Box<CStr>> for CString { - /// Converts a <code>[Box]<[CStr]></code> into a [`CString`] without copying or allocating. - #[inline] - fn from(s: Box<CStr>) -> CString { - s.into_c_string() - } -} - -#[stable(feature = "cstring_from_vec_of_nonzerou8", since = "1.43.0")] -impl From<Vec<NonZeroU8>> for CString { - /// Converts a <code>[Vec]<[NonZeroU8]></code> into a [`CString`] without - /// copying nor checking for inner null bytes. - #[inline] - fn from(v: Vec<NonZeroU8>) -> CString { - unsafe { - // Transmute `Vec<NonZeroU8>` to `Vec<u8>`. - let v: Vec<u8> = { - // SAFETY: - // - transmuting between `NonZeroU8` and `u8` is sound; - // - `alloc::Layout<NonZeroU8> == alloc::Layout<u8>`. - let (ptr, len, cap): (*mut NonZeroU8, _, _) = Vec::into_raw_parts(v); - Vec::from_raw_parts(ptr.cast::<u8>(), len, cap) - }; - // SAFETY: `v` cannot contain null bytes, given the type-level - // invariant of `NonZeroU8`. - Self::_from_vec_unchecked(v) - } - } -} - -#[stable(feature = "more_box_slice_clone", since = "1.29.0")] -impl Clone for Box<CStr> { - #[inline] - fn clone(&self) -> Self { - (**self).into() - } -} - -#[stable(feature = "box_from_c_string", since = "1.20.0")] -impl From<CString> for Box<CStr> { - /// Converts a [`CString`] into a <code>[Box]<[CStr]></code> without copying or allocating. - #[inline] - fn from(s: CString) -> Box<CStr> { - s.into_boxed_c_str() - } -} - -#[stable(feature = "cow_from_cstr", since = "1.28.0")] -impl<'a> From<CString> for Cow<'a, CStr> { - /// Converts a [`CString`] into an owned [`Cow`] without copying or allocating. - #[inline] - fn from(s: CString) -> Cow<'a, CStr> { - Cow::Owned(s) - } -} - -#[stable(feature = "cow_from_cstr", since = "1.28.0")] -impl<'a> From<&'a CStr> for Cow<'a, CStr> { - /// Converts a [`CStr`] into a borrowed [`Cow`] without copying or allocating. - #[inline] - fn from(s: &'a CStr) -> Cow<'a, CStr> { - Cow::Borrowed(s) - } -} - -#[stable(feature = "cow_from_cstr", since = "1.28.0")] -impl<'a> From<&'a CString> for Cow<'a, CStr> { - /// Converts a `&`[`CString`] into a borrowed [`Cow`] without copying or allocating. - #[inline] - fn from(s: &'a CString) -> Cow<'a, CStr> { - Cow::Borrowed(s.as_c_str()) - } -} - -#[stable(feature = "shared_from_slice2", since = "1.24.0")] -impl From<CString> for Arc<CStr> { - /// Converts a [`CString`] into an <code>[Arc]<[CStr]></code> by moving the [`CString`] - /// data into a new [`Arc`] buffer. - #[inline] - fn from(s: CString) -> Arc<CStr> { - let arc: Arc<[u8]> = Arc::from(s.into_inner()); - unsafe { Arc::from_raw(Arc::into_raw(arc) as *const CStr) } - } -} - -#[stable(feature = "shared_from_slice2", since = "1.24.0")] -impl From<&CStr> for Arc<CStr> { - /// Converts a `&CStr` into a `Arc<CStr>`, - /// by copying the contents into a newly allocated [`Arc`]. - #[inline] - fn from(s: &CStr) -> Arc<CStr> { - let arc: Arc<[u8]> = Arc::from(s.to_bytes_with_nul()); - unsafe { Arc::from_raw(Arc::into_raw(arc) as *const CStr) } - } -} - -#[stable(feature = "shared_from_slice2", since = "1.24.0")] -impl From<CString> for Rc<CStr> { - /// Converts a [`CString`] into an <code>[Rc]<[CStr]></code> by moving the [`CString`] - /// data into a new [`Arc`] buffer. - #[inline] - fn from(s: CString) -> Rc<CStr> { - let rc: Rc<[u8]> = Rc::from(s.into_inner()); - unsafe { Rc::from_raw(Rc::into_raw(rc) as *const CStr) } - } -} - -#[stable(feature = "shared_from_slice2", since = "1.24.0")] -impl From<&CStr> for Rc<CStr> { - /// Converts a `&CStr` into a `Rc<CStr>`, - /// by copying the contents into a newly allocated [`Rc`]. - #[inline] - fn from(s: &CStr) -> Rc<CStr> { - let rc: Rc<[u8]> = Rc::from(s.to_bytes_with_nul()); - unsafe { Rc::from_raw(Rc::into_raw(rc) as *const CStr) } - } -} - -#[stable(feature = "default_box_extra", since = "1.17.0")] -impl Default for Box<CStr> { - fn default() -> Box<CStr> { - let boxed: Box<[u8]> = Box::from([0]); - unsafe { Box::from_raw(Box::into_raw(boxed) as *mut CStr) } - } -} - -impl NulError { - /// Returns the position of the nul byte in the slice that caused - /// [`CString::new`] to fail. - /// - /// # Examples - /// - /// ``` - /// use std::ffi::CString; - /// - /// let nul_error = CString::new("foo\0bar").unwrap_err(); - /// assert_eq!(nul_error.nul_position(), 3); - /// - /// let nul_error = CString::new("foo bar\0").unwrap_err(); - /// assert_eq!(nul_error.nul_position(), 7); - /// ``` - #[must_use] - #[stable(feature = "rust1", since = "1.0.0")] - pub fn nul_position(&self) -> usize { - self.0 - } - - /// Consumes this error, returning the underlying vector of bytes which - /// generated the error in the first place. - /// - /// # Examples - /// - /// ``` - /// use std::ffi::CString; - /// - /// let nul_error = CString::new("foo\0bar").unwrap_err(); - /// assert_eq!(nul_error.into_vec(), b"foo\0bar"); - /// ``` - #[must_use = "`self` will be dropped if the result is not used"] - #[stable(feature = "rust1", since = "1.0.0")] - pub fn into_vec(self) -> Vec<u8> { - self.1 - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl Error for NulError { - #[allow(deprecated)] - fn description(&self) -> &str { - "nul byte found in data" - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl fmt::Display for NulError { - fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { - write!(f, "nul byte found in provided data at position: {}", self.0) - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl From<NulError> for io::Error { - /// Converts a [`NulError`] into a [`io::Error`]. - fn from(_: NulError) -> io::Error { - io::const_io_error!(io::ErrorKind::InvalidInput, "data provided contains a nul byte") - } -} - -#[stable(feature = "frombyteswithnulerror_impls", since = "1.17.0")] -impl Error for FromBytesWithNulError { - #[allow(deprecated)] - fn description(&self) -> &str { - match self.kind { - FromBytesWithNulErrorKind::InteriorNul(..) => { - "data provided contains an interior nul byte" - } - FromBytesWithNulErrorKind::NotNulTerminated => "data provided is not nul terminated", - } - } -} - -#[stable(feature = "frombyteswithnulerror_impls", since = "1.17.0")] -impl fmt::Display for FromBytesWithNulError { - #[allow(deprecated, deprecated_in_future)] - fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { - f.write_str(self.description())?; - if let FromBytesWithNulErrorKind::InteriorNul(pos) = self.kind { - write!(f, " at byte pos {pos}")?; - } - Ok(()) - } -} - -#[stable(feature = "cstring_from_vec_with_nul", since = "1.58.0")] -impl Error for FromVecWithNulError {} - -#[stable(feature = "cstring_from_vec_with_nul", since = "1.58.0")] -impl fmt::Display for FromVecWithNulError { - fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { - match self.error_kind { - FromBytesWithNulErrorKind::InteriorNul(pos) => { - write!(f, "data provided contains an interior nul byte at pos {pos}") - } - FromBytesWithNulErrorKind::NotNulTerminated => { - write!(f, "data provided is not nul terminated") - } - } - } -} - -impl IntoStringError { - /// Consumes this error, returning original [`CString`] which generated the - /// error. - #[must_use = "`self` will be dropped if the result is not used"] - #[stable(feature = "cstring_into", since = "1.7.0")] - pub fn into_cstring(self) -> CString { - self.inner - } - - /// Access the underlying UTF-8 error that was the cause of this error. - #[must_use] - #[stable(feature = "cstring_into", since = "1.7.0")] - pub fn utf8_error(&self) -> Utf8Error { - self.error - } -} - -#[stable(feature = "cstring_into", since = "1.7.0")] -impl Error for IntoStringError { - #[allow(deprecated)] - fn description(&self) -> &str { - "C string contained non-utf8 bytes" - } - - fn source(&self) -> Option<&(dyn Error + 'static)> { - Some(&self.error) - } -} - -#[stable(feature = "cstring_into", since = "1.7.0")] -impl fmt::Display for IntoStringError { - #[allow(deprecated, deprecated_in_future)] - fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { - self.description().fmt(f) - } -} - -impl CStr { - /// Wraps a raw C string with a safe C string wrapper. - /// - /// This function will wrap the provided `ptr` with a `CStr` wrapper, which - /// allows inspection and interoperation of non-owned C strings. The total - /// size of the raw C string must be smaller than `isize::MAX` **bytes** - /// in memory due to calling the `slice::from_raw_parts` function. - /// This method is unsafe for a number of reasons: - /// - /// * There is no guarantee to the validity of `ptr`. - /// * The returned lifetime is not guaranteed to be the actual lifetime of - /// `ptr`. - /// * There is no guarantee that the memory pointed to by `ptr` contains a - /// valid nul terminator byte at the end of the string. - /// * It is not guaranteed that the memory pointed by `ptr` won't change - /// before the `CStr` has been destroyed. - /// - /// > **Note**: This operation is intended to be a 0-cost cast but it is - /// > currently implemented with an up-front calculation of the length of - /// > the string. This is not guaranteed to always be the case. - /// - /// # Examples - /// - /// ```ignore (extern-declaration) - /// # fn main() { - /// use std::ffi::CStr; - /// use std::os::raw::c_char; - /// - /// extern "C" { - /// fn my_string() -> *const c_char; - /// } - /// - /// unsafe { - /// let slice = CStr::from_ptr(my_string()); - /// println!("string returned: {}", slice.to_str().unwrap()); - /// } - /// # } - /// ``` - #[inline] - #[must_use] - #[stable(feature = "rust1", since = "1.0.0")] - pub unsafe fn from_ptr<'a>(ptr: *const c_char) -> &'a CStr { - // SAFETY: The caller has provided a pointer that points to a valid C - // string with a NUL terminator of size less than `isize::MAX`, whose - // content remain valid and doesn't change for the lifetime of the - // returned `CStr`. - // - // Thus computing the length is fine (a NUL byte exists), the call to - // from_raw_parts is safe because we know the length is at most `isize::MAX`, meaning - // the call to `from_bytes_with_nul_unchecked` is correct. - // - // The cast from c_char to u8 is ok because a c_char is always one byte. - unsafe { - let len = sys::strlen(ptr); - let ptr = ptr as *const u8; - Self::_from_bytes_with_nul_unchecked(slice::from_raw_parts(ptr, len as usize + 1)) - } - } - - /// Creates a C string wrapper from a byte slice. - /// - /// This method will create a `CStr` from any byte slice that contains at - /// least one nul byte. The caller does not need to know or specify where - /// the nul byte is located. - /// - /// If the first byte is a nul character, this method will return an - /// empty `CStr`. If multiple nul characters are present, the `CStr` will - /// end at the first one. - /// - /// If the slice only has a single nul byte at the end, this method is - /// equivalent to [`CStr::from_bytes_with_nul`]. - /// - /// # Examples - /// ``` - /// #![feature(cstr_from_bytes_until_nul)] - /// - /// use std::ffi::CStr; - /// - /// let mut buffer = [0u8; 16]; - /// unsafe { - /// // Here we might call an unsafe C function that writes a string - /// // into the buffer. - /// let buf_ptr = buffer.as_mut_ptr(); - /// buf_ptr.write_bytes(b'A', 8); - /// } - /// // Attempt to extract a C nul-terminated string from the buffer. - /// let c_str = CStr::from_bytes_until_nul(&buffer[..]).unwrap(); - /// assert_eq!(c_str.to_str().unwrap(), "AAAAAAAA"); - /// ``` - /// - #[unstable(feature = "cstr_from_bytes_until_nul", issue = "95027")] - pub fn from_bytes_until_nul(bytes: &[u8]) -> Result<&CStr, FromBytesUntilNulError> { - let nul_pos = memchr::memchr(0, bytes); - match nul_pos { - Some(nul_pos) => { - // SAFETY: We know there is a nul byte at nul_pos, so this slice - // (ending at the nul byte) is a well-formed C string. - let subslice = &bytes[..nul_pos + 1]; - Ok(unsafe { CStr::from_bytes_with_nul_unchecked(subslice) }) - } - None => Err(FromBytesUntilNulError(())), - } - } - - /// Creates a C string wrapper from a byte slice. - /// - /// This function will cast the provided `bytes` to a `CStr` - /// wrapper after ensuring that the byte slice is nul-terminated - /// and does not contain any interior nul bytes. - /// - /// If the nul byte may not be at the end, - /// [`CStr::from_bytes_until_nul`] can be used instead. - /// - /// # Examples - /// - /// ``` - /// use std::ffi::CStr; - /// - /// let cstr = CStr::from_bytes_with_nul(b"hello\0"); - /// assert!(cstr.is_ok()); - /// ``` - /// - /// Creating a `CStr` without a trailing nul terminator is an error: - /// - /// ``` - /// use std::ffi::CStr; - /// - /// let cstr = CStr::from_bytes_with_nul(b"hello"); - /// assert!(cstr.is_err()); - /// ``` - /// - /// Creating a `CStr` with an interior nul byte is an error: - /// - /// ``` - /// use std::ffi::CStr; - /// - /// let cstr = CStr::from_bytes_with_nul(b"he\0llo\0"); - /// assert!(cstr.is_err()); - /// ``` - #[stable(feature = "cstr_from_bytes", since = "1.10.0")] - pub fn from_bytes_with_nul(bytes: &[u8]) -> Result<&Self, FromBytesWithNulError> { - let nul_pos = memchr::memchr(0, bytes); - match nul_pos { - Some(nul_pos) if nul_pos + 1 == bytes.len() => { - // SAFETY: We know there is only one nul byte, at the end - // of the byte slice. - Ok(unsafe { Self::_from_bytes_with_nul_unchecked(bytes) }) - } - Some(nul_pos) => Err(FromBytesWithNulError::interior_nul(nul_pos)), - None => Err(FromBytesWithNulError::not_nul_terminated()), - } - } - - /// Unsafely creates a C string wrapper from a byte slice. - /// - /// This function will cast the provided `bytes` to a `CStr` wrapper without - /// performing any sanity checks. The provided slice **must** be nul-terminated - /// and not contain any interior nul bytes. - /// - /// # Examples - /// - /// ``` - /// use std::ffi::{CStr, CString}; - /// - /// unsafe { - /// let cstring = CString::new("hello").expect("CString::new failed"); - /// let cstr = CStr::from_bytes_with_nul_unchecked(cstring.to_bytes_with_nul()); - /// assert_eq!(cstr, &*cstring); - /// } - /// ``` - #[inline] - #[must_use] - #[stable(feature = "cstr_from_bytes", since = "1.10.0")] - #[rustc_const_stable(feature = "const_cstr_unchecked", since = "1.59.0")] - pub const unsafe fn from_bytes_with_nul_unchecked(bytes: &[u8]) -> &CStr { - // We're in a const fn, so this is the best we can do - debug_assert!(!bytes.is_empty() && bytes[bytes.len() - 1] == 0); - unsafe { Self::_from_bytes_with_nul_unchecked(bytes) } - } - - #[inline] - const unsafe fn _from_bytes_with_nul_unchecked(bytes: &[u8]) -> &Self { - // SAFETY: Casting to CStr is safe because its internal representation - // is a [u8] too (safe only inside std). - // Dereferencing the obtained pointer is safe because it comes from a - // reference. Making a reference is then safe because its lifetime - // is bound by the lifetime of the given `bytes`. - unsafe { &*(bytes as *const [u8] as *const Self) } - } - - /// Returns the inner pointer to this C string. - /// - /// The returned pointer will be valid for as long as `self` is, and points - /// to a contiguous region of memory terminated with a 0 byte to represent - /// the end of the string. - /// - /// **WARNING** - /// - /// The returned pointer is read-only; writing to it (including passing it - /// to C code that writes to it) causes undefined behavior. - /// - /// It is your responsibility to make sure that the underlying memory is not - /// freed too early. For example, the following code will cause undefined - /// behavior when `ptr` is used inside the `unsafe` block: - /// - /// ```no_run - /// # #![allow(unused_must_use)] #![allow(temporary_cstring_as_ptr)] - /// use std::ffi::CString; - /// - /// let ptr = CString::new("Hello").expect("CString::new failed").as_ptr(); - /// unsafe { - /// // `ptr` is dangling - /// *ptr; - /// } - /// ``` - /// - /// This happens because the pointer returned by `as_ptr` does not carry any - /// lifetime information and the [`CString`] is deallocated immediately after - /// the `CString::new("Hello").expect("CString::new failed").as_ptr()` - /// expression is evaluated. - /// To fix the problem, bind the `CString` to a local variable: - /// - /// ```no_run - /// # #![allow(unused_must_use)] - /// use std::ffi::CString; - /// - /// let hello = CString::new("Hello").expect("CString::new failed"); - /// let ptr = hello.as_ptr(); - /// unsafe { - /// // `ptr` is valid because `hello` is in scope - /// *ptr; - /// } - /// ``` - /// - /// This way, the lifetime of the [`CString`] in `hello` encompasses - /// the lifetime of `ptr` and the `unsafe` block. - #[inline] - #[must_use] - #[stable(feature = "rust1", since = "1.0.0")] - #[rustc_const_stable(feature = "const_str_as_ptr", since = "1.32.0")] - pub const fn as_ptr(&self) -> *const c_char { - self.inner.as_ptr() - } - - /// Converts this C string to a byte slice. - /// - /// The returned slice will **not** contain the trailing nul terminator that this C - /// string has. - /// - /// > **Note**: This method is currently implemented as a constant-time - /// > cast, but it is planned to alter its definition in the future to - /// > perform the length calculation whenever this method is called. - /// - /// # Examples - /// - /// ``` - /// use std::ffi::CStr; - /// - /// let cstr = CStr::from_bytes_with_nul(b"foo\0").expect("CStr::from_bytes_with_nul failed"); - /// assert_eq!(cstr.to_bytes(), b"foo"); - /// ``` - #[inline] - #[must_use = "this returns the result of the operation, \ - without modifying the original"] - #[stable(feature = "rust1", since = "1.0.0")] - pub fn to_bytes(&self) -> &[u8] { - let bytes = self.to_bytes_with_nul(); - // SAFETY: to_bytes_with_nul returns slice with length at least 1 - unsafe { bytes.get_unchecked(..bytes.len() - 1) } - } - - /// Converts this C string to a byte slice containing the trailing 0 byte. - /// - /// This function is the equivalent of [`CStr::to_bytes`] except that it - /// will retain the trailing nul terminator instead of chopping it off. - /// - /// > **Note**: This method is currently implemented as a 0-cost cast, but - /// > it is planned to alter its definition in the future to perform the - /// > length calculation whenever this method is called. - /// - /// # Examples - /// - /// ``` - /// use std::ffi::CStr; - /// - /// let cstr = CStr::from_bytes_with_nul(b"foo\0").expect("CStr::from_bytes_with_nul failed"); - /// assert_eq!(cstr.to_bytes_with_nul(), b"foo\0"); - /// ``` - #[inline] - #[must_use = "this returns the result of the operation, \ - without modifying the original"] - #[stable(feature = "rust1", since = "1.0.0")] - pub fn to_bytes_with_nul(&self) -> &[u8] { - unsafe { &*(&self.inner as *const [c_char] as *const [u8]) } - } - - /// Yields a <code>&[str]</code> slice if the `CStr` contains valid UTF-8. - /// - /// If the contents of the `CStr` are valid UTF-8 data, this - /// function will return the corresponding <code>&[str]</code> slice. Otherwise, - /// it will return an error with details of where UTF-8 validation failed. - /// - /// [str]: prim@str "str" - /// - /// # Examples - /// - /// ``` - /// use std::ffi::CStr; - /// - /// let cstr = CStr::from_bytes_with_nul(b"foo\0").expect("CStr::from_bytes_with_nul failed"); - /// assert_eq!(cstr.to_str(), Ok("foo")); - /// ``` - #[stable(feature = "cstr_to_str", since = "1.4.0")] - pub fn to_str(&self) -> Result<&str, str::Utf8Error> { - // N.B., when `CStr` is changed to perform the length check in `.to_bytes()` - // instead of in `from_ptr()`, it may be worth considering if this should - // be rewritten to do the UTF-8 check inline with the length calculation - // instead of doing it afterwards. - str::from_utf8(self.to_bytes()) - } - - /// Converts a `CStr` into a <code>[Cow]<[str]></code>. - /// - /// If the contents of the `CStr` are valid UTF-8 data, this - /// function will return a <code>[Cow]::[Borrowed]\(&[str])</code> - /// with the corresponding <code>&[str]</code> slice. Otherwise, it will - /// replace any invalid UTF-8 sequences with - /// [`U+FFFD REPLACEMENT CHARACTER`][U+FFFD] and return a - /// <code>[Cow]::[Owned]\(&[str])</code> with the result. - /// - /// [str]: prim@str "str" - /// [Borrowed]: Cow::Borrowed - /// [Owned]: Cow::Owned - /// [U+FFFD]: crate::char::REPLACEMENT_CHARACTER "std::char::REPLACEMENT_CHARACTER" - /// - /// # Examples - /// - /// Calling `to_string_lossy` on a `CStr` containing valid UTF-8: - /// - /// ``` - /// use std::borrow::Cow; - /// use std::ffi::CStr; - /// - /// let cstr = CStr::from_bytes_with_nul(b"Hello World\0") - /// .expect("CStr::from_bytes_with_nul failed"); - /// assert_eq!(cstr.to_string_lossy(), Cow::Borrowed("Hello World")); - /// ``` - /// - /// Calling `to_string_lossy` on a `CStr` containing invalid UTF-8: - /// - /// ``` - /// use std::borrow::Cow; - /// use std::ffi::CStr; - /// - /// let cstr = CStr::from_bytes_with_nul(b"Hello \xF0\x90\x80World\0") - /// .expect("CStr::from_bytes_with_nul failed"); - /// assert_eq!( - /// cstr.to_string_lossy(), - /// Cow::Owned(String::from("Hello �World")) as Cow<'_, str> - /// ); - /// ``` - #[must_use = "this returns the result of the operation, \ - without modifying the original"] - #[stable(feature = "cstr_to_str", since = "1.4.0")] - pub fn to_string_lossy(&self) -> Cow<'_, str> { - String::from_utf8_lossy(self.to_bytes()) - } - - /// Converts a <code>[Box]<[CStr]></code> into a [`CString`] without copying or allocating. - /// - /// # Examples - /// - /// ``` - /// use std::ffi::CString; - /// - /// let c_string = CString::new(b"foo".to_vec()).expect("CString::new failed"); - /// let boxed = c_string.into_boxed_c_str(); - /// assert_eq!(boxed.into_c_string(), CString::new("foo").expect("CString::new failed")); - /// ``` - #[must_use = "`self` will be dropped if the result is not used"] - #[stable(feature = "into_boxed_c_str", since = "1.20.0")] - pub fn into_c_string(self: Box<CStr>) -> CString { - let raw = Box::into_raw(self) as *mut [u8]; - CString { inner: unsafe { Box::from_raw(raw) } } - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl PartialEq for CStr { - fn eq(&self, other: &CStr) -> bool { - self.to_bytes().eq(other.to_bytes()) - } -} -#[stable(feature = "rust1", since = "1.0.0")] -impl Eq for CStr {} -#[stable(feature = "rust1", since = "1.0.0")] -impl PartialOrd for CStr { - fn partial_cmp(&self, other: &CStr) -> Option<Ordering> { - self.to_bytes().partial_cmp(&other.to_bytes()) - } -} -#[stable(feature = "rust1", since = "1.0.0")] -impl Ord for CStr { - fn cmp(&self, other: &CStr) -> Ordering { - self.to_bytes().cmp(&other.to_bytes()) - } -} - -#[stable(feature = "cstr_borrow", since = "1.3.0")] -impl ToOwned for CStr { - type Owned = CString; - - fn to_owned(&self) -> CString { - CString { inner: self.to_bytes_with_nul().into() } - } - - fn clone_into(&self, target: &mut CString) { - let mut b = Vec::from(mem::take(&mut target.inner)); - self.to_bytes_with_nul().clone_into(&mut b); - target.inner = b.into_boxed_slice(); - } -} - -#[stable(feature = "cstring_asref", since = "1.7.0")] -impl From<&CStr> for CString { - /// Copies the contents of the `&CStr` into a newly allocated `CString`. - fn from(s: &CStr) -> CString { - s.to_owned() - } -} - -#[stable(feature = "cstring_asref", since = "1.7.0")] -impl ops::Index<ops::RangeFull> for CString { - type Output = CStr; - - #[inline] - fn index(&self, _index: ops::RangeFull) -> &CStr { - self - } -} - -#[stable(feature = "cstr_range_from", since = "1.47.0")] -impl ops::Index<ops::RangeFrom<usize>> for CStr { - type Output = CStr; - - fn index(&self, index: ops::RangeFrom<usize>) -> &CStr { - let bytes = self.to_bytes_with_nul(); - // we need to manually check the starting index to account for the null - // byte, since otherwise we could get an empty string that doesn't end - // in a null. - if index.start < bytes.len() { - unsafe { CStr::_from_bytes_with_nul_unchecked(&bytes[index.start..]) } - } else { - panic!( - "index out of bounds: the len is {} but the index is {}", - bytes.len(), - index.start - ); - } - } -} - -#[stable(feature = "cstring_asref", since = "1.7.0")] -impl AsRef<CStr> for CStr { - #[inline] - fn as_ref(&self) -> &CStr { - self - } -} - -#[stable(feature = "cstring_asref", since = "1.7.0")] -impl AsRef<CStr> for CString { - #[inline] - fn as_ref(&self) -> &CStr { - self - } -} diff --git a/library/std/src/ffi/c_str/tests.rs b/library/std/src/ffi/c_str/tests.rs deleted file mode 100644 index c20da138a18..00000000000 --- a/library/std/src/ffi/c_str/tests.rs +++ /dev/null @@ -1,240 +0,0 @@ -use super::*; -use crate::borrow::Cow::{Borrowed, Owned}; -use crate::collections::hash_map::DefaultHasher; -use crate::hash::{Hash, Hasher}; -use crate::os::raw::c_char; -use crate::rc::Rc; -use crate::sync::Arc; - -#[test] -fn c_to_rust() { - let data = b"123\0"; - let ptr = data.as_ptr() as *const c_char; - unsafe { - assert_eq!(CStr::from_ptr(ptr).to_bytes(), b"123"); - assert_eq!(CStr::from_ptr(ptr).to_bytes_with_nul(), b"123\0"); - } -} - -#[test] -fn simple() { - let s = CString::new("1234").unwrap(); - assert_eq!(s.as_bytes(), b"1234"); - assert_eq!(s.as_bytes_with_nul(), b"1234\0"); -} - -#[test] -fn build_with_zero1() { - assert!(CString::new(&b"\0"[..]).is_err()); -} -#[test] -fn build_with_zero2() { - assert!(CString::new(vec![0]).is_err()); -} - -#[test] -fn formatted() { - let s = CString::new(&b"abc\x01\x02\n\xE2\x80\xA6\xFF"[..]).unwrap(); - assert_eq!(format!("{s:?}"), r#""abc\x01\x02\n\xe2\x80\xa6\xff""#); -} - -#[test] -fn borrowed() { - unsafe { - let s = CStr::from_ptr(b"12\0".as_ptr() as *const _); - assert_eq!(s.to_bytes(), b"12"); - assert_eq!(s.to_bytes_with_nul(), b"12\0"); - } -} - -#[test] -fn to_str() { - let data = b"123\xE2\x80\xA6\0"; - let ptr = data.as_ptr() as *const c_char; - unsafe { - assert_eq!(CStr::from_ptr(ptr).to_str(), Ok("123…")); - assert_eq!(CStr::from_ptr(ptr).to_string_lossy(), Borrowed("123…")); - } - let data = b"123\xE2\0"; - let ptr = data.as_ptr() as *const c_char; - unsafe { - assert!(CStr::from_ptr(ptr).to_str().is_err()); - assert_eq!(CStr::from_ptr(ptr).to_string_lossy(), Owned::<str>(format!("123\u{FFFD}"))); - } -} - -#[test] -fn to_owned() { - let data = b"123\0"; - let ptr = data.as_ptr() as *const c_char; - - let owned = unsafe { CStr::from_ptr(ptr).to_owned() }; - assert_eq!(owned.as_bytes_with_nul(), data); -} - -#[test] -fn equal_hash() { - let data = b"123\xE2\xFA\xA6\0"; - let ptr = data.as_ptr() as *const c_char; - let cstr: &'static CStr = unsafe { CStr::from_ptr(ptr) }; - - let mut s = DefaultHasher::new(); - cstr.hash(&mut s); - let cstr_hash = s.finish(); - let mut s = DefaultHasher::new(); - CString::new(&data[..data.len() - 1]).unwrap().hash(&mut s); - let cstring_hash = s.finish(); - - assert_eq!(cstr_hash, cstring_hash); -} - -#[test] -fn from_bytes_with_nul() { - let data = b"123\0"; - let cstr = CStr::from_bytes_with_nul(data); - assert_eq!(cstr.map(CStr::to_bytes), Ok(&b"123"[..])); - let cstr = CStr::from_bytes_with_nul(data); - assert_eq!(cstr.map(CStr::to_bytes_with_nul), Ok(&b"123\0"[..])); - - unsafe { - let cstr = CStr::from_bytes_with_nul(data); - let cstr_unchecked = CStr::from_bytes_with_nul_unchecked(data); - assert_eq!(cstr, Ok(cstr_unchecked)); - } -} - -#[test] -fn from_bytes_with_nul_unterminated() { - let data = b"123"; - let cstr = CStr::from_bytes_with_nul(data); - assert!(cstr.is_err()); -} - -#[test] -fn from_bytes_with_nul_interior() { - let data = b"1\023\0"; - let cstr = CStr::from_bytes_with_nul(data); - assert!(cstr.is_err()); -} - -#[test] -fn cstr_from_bytes_until_nul() { - // Test an empty slice. This should fail because it - // does not contain a nul byte. - let b = b""; - assert_eq!(CStr::from_bytes_until_nul(&b[..]), Err(FromBytesUntilNulError(()))); - - // Test a non-empty slice, that does not contain a nul byte. - let b = b"hello"; - assert_eq!(CStr::from_bytes_until_nul(&b[..]), Err(FromBytesUntilNulError(()))); - - // Test an empty nul-terminated string - let b = b"\0"; - let r = CStr::from_bytes_until_nul(&b[..]).unwrap(); - assert_eq!(r.to_bytes(), b""); - - // Test a slice with the nul byte in the middle - let b = b"hello\0world!"; - let r = CStr::from_bytes_until_nul(&b[..]).unwrap(); - assert_eq!(r.to_bytes(), b"hello"); - - // Test a slice with the nul byte at the end - let b = b"hello\0"; - let r = CStr::from_bytes_until_nul(&b[..]).unwrap(); - assert_eq!(r.to_bytes(), b"hello"); - - // Test a slice with two nul bytes at the end - let b = b"hello\0\0"; - let r = CStr::from_bytes_until_nul(&b[..]).unwrap(); - assert_eq!(r.to_bytes(), b"hello"); - - // Test a slice containing lots of nul bytes - let b = b"\0\0\0\0"; - let r = CStr::from_bytes_until_nul(&b[..]).unwrap(); - assert_eq!(r.to_bytes(), b""); -} - -#[test] -fn into_boxed() { - let orig: &[u8] = b"Hello, world!\0"; - let cstr = CStr::from_bytes_with_nul(orig).unwrap(); - let boxed: Box<CStr> = Box::from(cstr); - let cstring = cstr.to_owned().into_boxed_c_str().into_c_string(); - assert_eq!(cstr, &*boxed); - assert_eq!(&*boxed, &*cstring); - assert_eq!(&*cstring, cstr); -} - -#[test] -fn boxed_default() { - let boxed = <Box<CStr>>::default(); - assert_eq!(boxed.to_bytes_with_nul(), &[0]); -} - -#[test] -fn test_c_str_clone_into() { - let mut c_string = CString::new("lorem").unwrap(); - let c_ptr = c_string.as_ptr(); - let c_str = CStr::from_bytes_with_nul(b"ipsum\0").unwrap(); - c_str.clone_into(&mut c_string); - assert_eq!(c_str, c_string.as_c_str()); - // The exact same size shouldn't have needed to move its allocation - assert_eq!(c_ptr, c_string.as_ptr()); -} - -#[test] -fn into_rc() { - let orig: &[u8] = b"Hello, world!\0"; - let cstr = CStr::from_bytes_with_nul(orig).unwrap(); - let rc: Rc<CStr> = Rc::from(cstr); - let arc: Arc<CStr> = Arc::from(cstr); - - assert_eq!(&*rc, cstr); - assert_eq!(&*arc, cstr); - - let rc2: Rc<CStr> = Rc::from(cstr.to_owned()); - let arc2: Arc<CStr> = Arc::from(cstr.to_owned()); - - assert_eq!(&*rc2, cstr); - assert_eq!(&*arc2, cstr); -} - -#[test] -fn cstr_const_constructor() { - const CSTR: &CStr = unsafe { CStr::from_bytes_with_nul_unchecked(b"Hello, world!\0") }; - - assert_eq!(CSTR.to_str().unwrap(), "Hello, world!"); -} - -#[test] -fn cstr_index_from() { - let original = b"Hello, world!\0"; - let cstr = CStr::from_bytes_with_nul(original).unwrap(); - let result = CStr::from_bytes_with_nul(&original[7..]).unwrap(); - - assert_eq!(&cstr[7..], result); -} - -#[test] -#[should_panic] -fn cstr_index_from_empty() { - let original = b"Hello, world!\0"; - let cstr = CStr::from_bytes_with_nul(original).unwrap(); - let _ = &cstr[original.len()..]; -} - -#[test] -fn c_string_from_empty_string() { - let original = ""; - let cstring = CString::new(original).unwrap(); - assert_eq!(original.as_bytes(), cstring.as_bytes()); - assert_eq!([b'\0'], cstring.as_bytes_with_nul()); -} - -#[test] -fn c_str_from_empty_string() { - let original = b"\0"; - let cstr = CStr::from_bytes_with_nul(original).unwrap(); - assert_eq!([] as [u8; 0], cstr.to_bytes()); - assert_eq!([b'\0'], cstr.to_bytes_with_nul()); -} diff --git a/library/std/src/ffi/mod.rs b/library/std/src/ffi/mod.rs index 13e3dacc30d..5989ba71de0 100644 --- a/library/std/src/ffi/mod.rs +++ b/library/std/src/ffi/mod.rs @@ -146,12 +146,14 @@ #![stable(feature = "rust1", since = "1.0.0")] -#[stable(feature = "cstr_from_bytes", since = "1.10.0")] -pub use self::c_str::FromBytesWithNulError; #[stable(feature = "cstring_from_vec_with_nul", since = "1.58.0")] -pub use self::c_str::FromVecWithNulError; +pub use alloc::ffi::FromVecWithNulError; +#[stable(feature = "rust1", since = "1.0.0")] +pub use alloc::ffi::{CString, IntoStringError, NulError}; #[stable(feature = "rust1", since = "1.0.0")] -pub use self::c_str::{CStr, CString, IntoStringError, NulError}; +pub use core::ffi::CStr; +#[stable(feature = "cstr_from_bytes", since = "1.10.0")] +pub use core::ffi::FromBytesWithNulError; #[stable(feature = "rust1", since = "1.0.0")] pub use self::os_str::{OsStr, OsString}; @@ -176,5 +178,4 @@ pub use core::ffi::{c_ptrdiff_t, c_size_t, c_ssize_t}; )] pub use core::ffi::{VaList, VaListImpl}; -mod c_str; mod os_str; diff --git a/library/std/src/lib.rs b/library/std/src/lib.rs index 60e7c2af8e4..411a38038f1 100644 --- a/library/std/src/lib.rs +++ b/library/std/src/lib.rs @@ -261,6 +261,8 @@ #![feature(char_error_internals)] #![feature(char_internals)] #![feature(core_intrinsics)] +#![feature(cstr_from_bytes_until_nul)] +#![feature(cstr_internals)] #![feature(duration_checked_float)] #![feature(duration_constants)] #![feature(exact_size_is_empty)] diff --git a/library/std/src/prelude/v1.rs b/library/std/src/prelude/v1.rs index 0226c4d7a25..f7533696df4 100644 --- a/library/std/src/prelude/v1.rs +++ b/library/std/src/prelude/v1.rs @@ -95,3 +95,7 @@ pub use crate::string::{String, ToString}; #[stable(feature = "rust1", since = "1.0.0")] #[doc(no_inline)] pub use crate::vec::Vec; + +#[cfg(bootstrap)] +#[unstable(feature = "cstr_internals", issue = "none")] +pub use alloc::ffi::CStrExt; |