diff --git a/library/std/src/sys/windows/args.rs b/library/std/src/sys/windows/args.rs index 01f26298290f0..6741ae46d32dd 100644 --- a/library/std/src/sys/windows/args.rs +++ b/library/std/src/sys/windows/args.rs @@ -9,17 +9,16 @@ mod tests; use crate::ffi::OsString; use crate::fmt; use crate::io; -use crate::marker::PhantomData; use crate::num::NonZeroU16; use crate::os::windows::prelude::*; use crate::path::PathBuf; -use crate::ptr::NonNull; use crate::sys::c; use crate::sys::process::ensure_no_nuls; use crate::sys::windows::os::current_exe; +use crate::sys_common::wstr::WStrUnits; use crate::vec; -use core::iter; +use crate::iter; /// This is the const equivalent to `NonZeroU16::new(n).unwrap()` /// @@ -199,55 +198,6 @@ impl ExactSizeIterator for Args { } } -/// A safe iterator over a LPWSTR -/// (aka a pointer to a series of UTF-16 code units terminated by a NULL). -struct WStrUnits<'a> { - // The pointer must never be null... - lpwstr: NonNull, - // ...and the memory it points to must be valid for this lifetime. - lifetime: PhantomData<&'a [u16]>, -} -impl WStrUnits<'_> { - /// Create the iterator. Returns `None` if `lpwstr` is null. - /// - /// SAFETY: `lpwstr` must point to a null-terminated wide string that lives - /// at least as long as the lifetime of this struct. - unsafe fn new(lpwstr: *const u16) -> Option { - Some(Self { lpwstr: NonNull::new(lpwstr as _)?, lifetime: PhantomData }) - } - fn peek(&self) -> Option { - // SAFETY: It's always safe to read the current item because we don't - // ever move out of the array's bounds. - unsafe { NonZeroU16::new(*self.lpwstr.as_ptr()) } - } - /// Advance the iterator while `predicate` returns true. - /// Returns the number of items it advanced by. - fn advance_while bool>(&mut self, mut predicate: P) -> usize { - let mut counter = 0; - while let Some(w) = self.peek() { - if !predicate(w) { - break; - } - counter += 1; - self.next(); - } - counter - } -} -impl Iterator for WStrUnits<'_> { - // This can never return zero as that marks the end of the string. - type Item = NonZeroU16; - fn next(&mut self) -> Option { - // SAFETY: If NULL is reached we immediately return. - // Therefore it's safe to advance the pointer after that. - unsafe { - let next = self.peek()?; - self.lpwstr = NonNull::new_unchecked(self.lpwstr.as_ptr().add(1)); - Some(next) - } - } -} - #[derive(Debug)] pub(crate) enum Arg { /// Add quotes (if needed) diff --git a/library/std/src/sys_common/mod.rs b/library/std/src/sys_common/mod.rs index 8c19f9332dc56..53259e8dbbd46 100644 --- a/library/std/src/sys_common/mod.rs +++ b/library/std/src/sys_common/mod.rs @@ -35,6 +35,7 @@ pub mod thread; pub mod thread_info; pub mod thread_local_dtor; pub mod thread_parker; +pub mod wstr; pub mod wtf8; cfg_if::cfg_if! { diff --git a/library/std/src/sys_common/wstr.rs b/library/std/src/sys_common/wstr.rs new file mode 100644 index 0000000000000..b230fd1a829f7 --- /dev/null +++ b/library/std/src/sys_common/wstr.rs @@ -0,0 +1,59 @@ +//! This module contains constructs to work with 16-bit characters (UCS-2 or UTF-16) +#![allow(dead_code)] + +use crate::marker::PhantomData; +use crate::num::NonZeroU16; +use crate::ptr::NonNull; + +/// A safe iterator over a LPWSTR +/// (aka a pointer to a series of UTF-16 code units terminated by a NULL). +pub struct WStrUnits<'a> { + // The pointer must never be null... + lpwstr: NonNull, + // ...and the memory it points to must be valid for this lifetime. + lifetime: PhantomData<&'a [u16]>, +} + +impl WStrUnits<'_> { + /// Create the iterator. Returns `None` if `lpwstr` is null. + /// + /// SAFETY: `lpwstr` must point to a null-terminated wide string that lives + /// at least as long as the lifetime of this struct. + pub unsafe fn new(lpwstr: *const u16) -> Option { + Some(Self { lpwstr: NonNull::new(lpwstr as _)?, lifetime: PhantomData }) + } + + pub fn peek(&self) -> Option { + // SAFETY: It's always safe to read the current item because we don't + // ever move out of the array's bounds. + unsafe { NonZeroU16::new(*self.lpwstr.as_ptr()) } + } + + /// Advance the iterator while `predicate` returns true. + /// Returns the number of items it advanced by. + pub fn advance_while bool>(&mut self, mut predicate: P) -> usize { + let mut counter = 0; + while let Some(w) = self.peek() { + if !predicate(w) { + break; + } + counter += 1; + self.next(); + } + counter + } +} + +impl Iterator for WStrUnits<'_> { + // This can never return zero as that marks the end of the string. + type Item = NonZeroU16; + fn next(&mut self) -> Option { + // SAFETY: If NULL is reached we immediately return. + // Therefore it's safe to advance the pointer after that. + unsafe { + let next = self.peek()?; + self.lpwstr = NonNull::new_unchecked(self.lpwstr.as_ptr().add(1)); + Some(next) + } + } +}