non-linux platforms

Signed-off-by: Nick Cameron <nrc@ncameron.org>

Author: nrc

library/std/src/fs.rs

@@ -13,7 +13,7 @@ mod tests;
 
 use crate::ffi::OsString;
 use crate::fmt;
-use crate::io::{self, BorrowCursor, IoSlice, IoSliceMut, Read, Seek, SeekFrom, Write};
+use crate::io::{self, BorrowedCursor, IoSlice, IoSliceMut, Read, Seek, SeekFrom, Write};
 use crate::path::{Path, PathBuf};
 use crate::sys::fs as fs_imp;
 use crate::sys_common::{AsInner, AsInnerMut, FromInner, IntoInner};
@@ -703,7 +703,7 @@ impl Read for File {
         self.inner.read_vectored(bufs)
     }
 
-    fn read_buf(&mut self, cursor: BorrowCursor<'_, '_>) -> io::Result<()> {
+    fn read_buf(&mut self, cursor: BorrowedCursor<'_, '_>) -> io::Result<()> {
         self.inner.read_buf(cursor)
     }
 
@@ -755,7 +755,7 @@ impl Read for &File {
         self.inner.read(buf)
     }
 
-    fn read_buf(&mut self, cursor: BorrowCursor<'_, '_>) -> io::Result<()> {
+    fn read_buf(&mut self, cursor: BorrowedCursor<'_, '_>) -> io::Result<()> {
         self.inner.read_buf(cursor)
     }
 

library/std/src/io/buffered/bufreader.rs

@@ -2,8 +2,7 @@ mod buffer;
 
 use crate::fmt;
 use crate::io::{
-    self, BorrowBuf, BorrowCursor, BufRead, IoSliceMut, Read, Seek, SeekFrom, SizeHint,
-    DEFAULT_BUF_SIZE,
+    self, BorrowedCursor, BufRead, IoSliceMut, Read, Seek, SeekFrom, SizeHint, DEFAULT_BUF_SIZE,
 };
 use buffer::Buffer;
 
@@ -267,7 +266,7 @@ impl<R: Read> Read for BufReader<R> {
         Ok(nread)
     }
 
-    fn read_buf(&mut self, mut cursor: BorrowCursor<'_, '_>) -> io::Result<()> {
+    fn read_buf(&mut self, mut cursor: BorrowedCursor<'_, '_>) -> io::Result<()> {
         // If we don't have any buffered data and we're doing a massive read
         // (larger than our internal buffer), bypass our internal buffer
         // entirely.

library/std/src/io/buffered/bufreader/buffer.rs

@@ -9,7 +9,7 @@
 /// that user code which wants to do reads from a `BufReader` via `buffer` + `consume` can do so
 /// without encountering any runtime bounds checks.
 use crate::cmp;
-use crate::io::{self, Read, ReadBuf};
+use crate::io::{self, BorrowedBuf, Read};
 use crate::mem::MaybeUninit;
 
 pub struct Buffer {
@@ -93,11 +93,15 @@ impl Buffer {
         if self.pos >= self.filled {
             debug_assert!(self.pos == self.filled);
 
-            let mut readbuf = ReadBuf::uninit(&mut self.buf);
+            let mut buf: BorrowedBuf<'_> = (&mut *self.buf).into();
+            // SAFETY: `self.filled` bytes will always have been initialized.
+            unsafe {
+                buf.set_init(self.filled);
+            }
 
-            reader.read_buf(&mut readbuf)?;
+            reader.read_buf(buf.unfilled())?;
 
-            self.filled = readbuf.filled_len();
+            self.filled = buf.len();
             self.pos = 0;
         }
         Ok(self.buffer())

library/std/src/io/buffered/tests.rs

@@ -1,5 +1,7 @@
 use crate::io::prelude::*;
-use crate::io::{self, BorrowBuf, BufReader, BufWriter, ErrorKind, IoSlice, LineWriter, SeekFrom};
+use crate::io::{
+    self, BorrowedBuf, BufReader, BufWriter, ErrorKind, IoSlice, LineWriter, SeekFrom,
+};
 use crate::mem::MaybeUninit;
 use crate::panic;
 use crate::sync::atomic::{AtomicUsize, Ordering};
@@ -62,31 +64,31 @@ fn test_buffered_reader_read_buf() {
     let mut reader = BufReader::with_capacity(2, inner);
 
     let buf: &mut [_] = &mut [MaybeUninit::uninit(); 3];
-    let mut buf: BorrowBuf<'_> = buf.into();
+    let mut buf: BorrowedBuf<'_> = buf.into();
 
     reader.read_buf(buf.unfilled()).unwrap();
 
     assert_eq!(buf.filled(), [5, 6, 7]);
     assert_eq!(reader.buffer(), []);
 
     let buf: &mut [_] = &mut [MaybeUninit::uninit(); 2];
-    let mut buf: BorrowBuf<'_> = buf.into();
+    let mut buf: BorrowedBuf<'_> = buf.into();
 
     reader.read_buf(buf.unfilled()).unwrap();
 
     assert_eq!(buf.filled(), [0, 1]);
     assert_eq!(reader.buffer(), []);
 
     let buf: &mut [_] = &mut [MaybeUninit::uninit(); 1];
-    let mut buf: BorrowBuf<'_> = buf.into();
+    let mut buf: BorrowedBuf<'_> = buf.into();
 
     reader.read_buf(buf.unfilled()).unwrap();
 
     assert_eq!(buf.filled(), [2]);
     assert_eq!(reader.buffer(), [3]);
 
     let buf: &mut [_] = &mut [MaybeUninit::uninit(); 3];
-    let mut buf: BorrowBuf<'_> = buf.into();
+    let mut buf: BorrowedBuf<'_> = buf.into();
 
     reader.read_buf(buf.unfilled()).unwrap();
 

library/std/src/io/copy.rs

@@ -1,4 +1,4 @@
-use super::{BorrowBuf, BufWriter, ErrorKind, Read, Result, Write, DEFAULT_BUF_SIZE};
+use super::{BorrowedBuf, BufWriter, ErrorKind, Read, Result, Write, DEFAULT_BUF_SIZE};
 use crate::mem::MaybeUninit;
 
 /// Copies the entire contents of a reader into a writer.
@@ -97,7 +97,7 @@ impl<I: Write> BufferedCopySpec for BufWriter<I> {
 
         loop {
             let buf = writer.buffer_mut();
-            let mut read_buf: BorrowBuf<'_> = buf.spare_capacity_mut().into();
+            let mut read_buf: BorrowedBuf<'_> = buf.spare_capacity_mut().into();
 
             unsafe {
                 // SAFETY: init is either 0 or the init_len from the previous iteration.
@@ -117,7 +117,7 @@ impl<I: Write> BufferedCopySpec for BufWriter<I> {
                         init = read_buf.init_len() - bytes_read;
                         len += bytes_read as u64;
 
-                        // SAFETY: BorrowBuf guarantees all of its filled bytes are init
+                        // SAFETY: BorrowedBuf guarantees all of its filled bytes are init
                         unsafe { buf.set_len(buf.len() + bytes_read) };
 
                         // Read again if the buffer still has enough capacity, as BufWriter itself would do
@@ -139,7 +139,7 @@ fn stack_buffer_copy<R: Read + ?Sized, W: Write + ?Sized>(
     writer: &mut W,
 ) -> Result<u64> {
     let buf: &mut [_] = &mut [MaybeUninit::uninit(); DEFAULT_BUF_SIZE];
-    let mut buf: BorrowBuf<'_> = buf.into();
+    let mut buf: BorrowedBuf<'_> = buf.into();
 
     let mut len = 0;
 

library/std/src/io/cursor.rs

@@ -5,7 +5,7 @@ use crate::io::prelude::*;
 
 use crate::alloc::Allocator;
 use crate::cmp;
-use crate::io::{self, BorrowCursor, ErrorKind, IoSlice, IoSliceMut, SeekFrom};
+use crate::io::{self, BorrowedCursor, ErrorKind, IoSlice, IoSliceMut, SeekFrom};
 
 /// A `Cursor` wraps an in-memory buffer and provides it with a
 /// [`Seek`] implementation.
@@ -323,7 +323,7 @@ where
         Ok(n)
     }
 
-    fn read_buf(&mut self, mut cursor: BorrowCursor<'_, '_>) -> io::Result<()> {
+    fn read_buf(&mut self, mut cursor: BorrowedCursor<'_, '_>) -> io::Result<()> {
         let prev_written = cursor.written();
 
         Read::read_buf(&mut self.fill_buf()?, cursor.clone())?;

library/std/src/io/impls.rs

@@ -6,7 +6,7 @@ use crate::cmp;
 use crate::collections::VecDeque;
 use crate::fmt;
 use crate::io::{
-    self, BorrowCursor, BufRead, ErrorKind, IoSlice, IoSliceMut, Read, Seek, SeekFrom, Write,
+    self, BorrowedCursor, BufRead, ErrorKind, IoSlice, IoSliceMut, Read, Seek, SeekFrom, Write,
 };
 use crate::mem;
 
@@ -21,7 +21,7 @@ impl<R: Read + ?Sized> Read for &mut R {
     }
 
     #[inline]
-    fn read_buf(&mut self, cursor: BorrowCursor<'_, '_>) -> io::Result<()> {
+    fn read_buf(&mut self, cursor: BorrowedCursor<'_, '_>) -> io::Result<()> {
         (**self).read_buf(cursor)
     }
 
@@ -125,7 +125,7 @@ impl<R: Read + ?Sized> Read for Box<R> {
     }
 
     #[inline]
-    fn read_buf(&mut self, cursor: BorrowCursor<'_, '_>) -> io::Result<()> {
+    fn read_buf(&mut self, cursor: BorrowedCursor<'_, '_>) -> io::Result<()> {
         (**self).read_buf(cursor)
     }
 
@@ -249,7 +249,7 @@ impl Read for &[u8] {
     }
 
     #[inline]
-    fn read_buf(&mut self, mut cursor: BorrowCursor<'_, '_>) -> io::Result<()> {
+    fn read_buf(&mut self, mut cursor: BorrowedCursor<'_, '_>) -> io::Result<()> {
         let amt = cmp::min(cursor.capacity(), self.len());
         let (a, b) = self.split_at(amt);
 
@@ -427,10 +427,10 @@ impl<A: Allocator> Read for VecDeque<u8, A> {
     }
 
     #[inline]
-    fn read_buf(&mut self, buf: &mut ReadBuf<'_>) -> io::Result<()> {
+    fn read_buf(&mut self, cursor: BorrowedCursor<'_, '_>) -> io::Result<()> {
         let (ref mut front, _) = self.as_slices();
-        let n = cmp::min(buf.remaining(), front.len());
-        Read::read_buf(front, buf)?;
+        let n = cmp::min(cursor.capacity(), front.len());
+        Read::read_buf(front, cursor)?;
         self.drain(..n);
         Ok(())
     }

library/std/src/io/mod.rs

@@ -278,7 +278,7 @@ pub use self::{
 };
 
 #[unstable(feature = "read_buf", issue = "78485")]
-pub use self::readbuf::{BorrowBuf, BorrowCursor};
+pub use self::readbuf::{BorrowedBuf, BorrowedCursor};
 pub(crate) use error::const_io_error;
 
 mod buffered;
@@ -362,7 +362,7 @@ pub(crate) fn default_read_to_end<R: Read + ?Sized>(r: &mut R, buf: &mut Vec<u8>
             buf.reserve(32); // buf is full, need more space
         }
 
-        let mut read_buf: BorrowBuf<'_> = buf.spare_capacity_mut().into();
+        let mut read_buf: BorrowedBuf<'_> = buf.spare_capacity_mut().into();
 
         // SAFETY: These bytes were initialized but not filled in the previous loop
         unsafe {
@@ -383,7 +383,7 @@ pub(crate) fn default_read_to_end<R: Read + ?Sized>(r: &mut R, buf: &mut Vec<u8>
         // store how much was initialized but not filled
         initialized = cursor.init_ref().len();
 
-        // SAFETY: BorrowBuf's invariants mean this much memory is initialized.
+        // SAFETY: BorrowedBuf's invariants mean this much memory is initialized.
         unsafe {
             let new_len = read_buf.filled().len() + buf.len();
             buf.set_len(new_len);
@@ -462,7 +462,7 @@ pub(crate) fn default_read_exact<R: Read + ?Sized>(this: &mut R, mut buf: &mut [
     }
 }
 
-pub(crate) fn default_read_buf<F>(read: F, mut cursor: BorrowCursor<'_, '_>) -> Result<()>
+pub(crate) fn default_read_buf<F>(read: F, mut cursor: BorrowedCursor<'_, '_>) -> Result<()>
 where
     F: FnOnce(&mut [u8]) -> Result<usize>,
 {
@@ -805,24 +805,23 @@ pub trait Read {
         default_read_exact(self, buf)
     }
 
-    // TODO naming, if should the method be read_cursor? Or should we change the names of the data structures?
     /// Pull some bytes from this source into the specified buffer.
     ///
-    /// This is equivalent to the [`read`](Read::read) method, except that it is passed a [`BorrowCursor`] rather than `[u8]` to allow use
+    /// This is equivalent to the [`read`](Read::read) method, except that it is passed a [`BorrowedCursor`] rather than `[u8]` to allow use
     /// with uninitialized buffers. The new data will be appended to any existing contents of `buf`.
     ///
     /// The default implementation delegates to `read`.
     #[unstable(feature = "read_buf", issue = "78485")]
-    fn read_buf(&mut self, buf: BorrowCursor<'_, '_>) -> Result<()> {
+    fn read_buf(&mut self, buf: BorrowedCursor<'_, '_>) -> Result<()> {
         default_read_buf(|b| self.read(b), buf)
     }
 
     /// Read the exact number of bytes required to fill `cursor`.
     ///
-    /// This is equivalent to the [`read_exact`](Read::read_exact) method, except that it is passed a [`BorrowCursor`] rather than `[u8]` to
+    /// This is equivalent to the [`read_exact`](Read::read_exact) method, except that it is passed a [`BorrowedCursor`] rather than `[u8]` to
     /// allow use with uninitialized buffers.
     #[unstable(feature = "read_buf", issue = "78485")]
-    fn read_buf_exact(&mut self, mut cursor: BorrowCursor<'_, '_>) -> Result<()> {
+    fn read_buf_exact(&mut self, mut cursor: BorrowedCursor<'_, '_>) -> Result<()> {
         while cursor.capacity() > 0 {
             let prev_written = cursor.written();
             match self.read_buf(cursor.clone()) {
@@ -2587,7 +2586,7 @@ impl<T: Read> Read for Take<T> {
         Ok(n)
     }
 
-    fn read_buf(&mut self, mut buf: BorrowCursor<'_, '_>) -> Result<()> {
+    fn read_buf(&mut self, mut buf: BorrowedCursor<'_, '_>) -> Result<()> {
         // Don't call into inner reader at all at EOF because it may still block
         if self.limit == 0 {
             return Ok(());
@@ -2602,7 +2601,7 @@ impl<T: Read> Read for Take<T> {
             // SAFETY: no uninit data is written to ibuf
             let ibuf = unsafe { &mut buf.as_mut()[..limit] };
 
-            let mut sliced_buf: BorrowBuf<'_> = ibuf.into();
+            let mut sliced_buf: BorrowedBuf<'_> = ibuf.into();
 
             // SAFETY: extra_init bytes of ibuf are known to be initialized
             unsafe {