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Remove Option from BufWriter

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Fixes #72925
This commit is contained in:
Alex Macleod 2021-07-15 20:04:14 +01:00
parent 1158367a6d
commit 8837bf1acd
1 changed files with 14 additions and 10 deletions
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24
library/std/src/io/buffered/bufwriter.rs
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@ -68,7 +68,7 @@ use crate::ptr;
/// [`flush`]: BufWriter::flush /// [`flush`]: BufWriter::flush
#[stable(feature = "rust1", since = "1.0.0")] #[stable(feature = "rust1", since = "1.0.0")]
pub struct BufWriter<W: Write> { pub struct BufWriter<W: Write> {
inner: Option<W>, inner: W,
// The buffer. Avoid using this like a normal `Vec` in common code paths. // The buffer. Avoid using this like a normal `Vec` in common code paths.
// That is, don't use `buf.push`, `buf.extend_from_slice`, or any other // That is, don't use `buf.push`, `buf.extend_from_slice`, or any other
// methods that require bounds checking or the like. This makes an enormous // methods that require bounds checking or the like. This makes an enormous
@ -112,7 +112,7 @@ impl<W: Write> BufWriter<W> {
/// ``` /// ```
#[stable(feature = "rust1", since = "1.0.0")] #[stable(feature = "rust1", since = "1.0.0")]
pub fn with_capacity(capacity: usize, inner: W) -> BufWriter<W> { pub fn with_capacity(capacity: usize, inner: W) -> BufWriter<W> {
BufWriter { inner: Some(inner), buf: Vec::with_capacity(capacity), panicked: false } BufWriter { inner, buf: Vec::with_capacity(capacity), panicked: false }
} }
/// Send data in our local buffer into the inner writer, looping as /// Send data in our local buffer into the inner writer, looping as
@ -161,10 +161,9 @@ impl<W: Write> BufWriter<W> {
} }
let mut guard = BufGuard::new(&mut self.buf); let mut guard = BufGuard::new(&mut self.buf);
let inner = self.inner.as_mut().unwrap();
while !guard.done() { while !guard.done() {
self.panicked = true; self.panicked = true;
let r = inner.write(guard.remaining()); let r = self.inner.write(guard.remaining());
self.panicked = false; self.panicked = false;
match r { match r {
@ -212,7 +211,7 @@ impl<W: Write> BufWriter<W> {
/// ``` /// ```
#[stable(feature = "rust1", since = "1.0.0")] #[stable(feature = "rust1", since = "1.0.0")]
pub fn get_ref(&self) -> &W { pub fn get_ref(&self) -> &W {
self.inner.as_ref().unwrap() &self.inner
} }
/// Gets a mutable reference to the underlying writer. /// Gets a mutable reference to the underlying writer.
@ -232,7 +231,7 @@ impl<W: Write> BufWriter<W> {
/// ``` /// ```
#[stable(feature = "rust1", since = "1.0.0")] #[stable(feature = "rust1", since = "1.0.0")]
pub fn get_mut(&mut self) -> &mut W { pub fn get_mut(&mut self) -> &mut W {
self.inner.as_mut().unwrap() &mut self.inner
} }
/// Returns a reference to the internally buffered data. /// Returns a reference to the internally buffered data.
@ -308,7 +307,7 @@ impl<W: Write> BufWriter<W> {
pub fn into_inner(mut self) -> Result<W, IntoInnerError<BufWriter<W>>> { pub fn into_inner(mut self) -> Result<W, IntoInnerError<BufWriter<W>>> {
match self.flush_buf() { match self.flush_buf() {
Err(e) => Err(IntoInnerError::new(self, e)), Err(e) => Err(IntoInnerError::new(self, e)),
Ok(()) => Ok(self.inner.take().unwrap()), Ok(()) => Ok(self.into_raw_parts().0),
} }
} }
@ -339,7 +338,12 @@ impl<W: Write> BufWriter<W> {
pub fn into_raw_parts(mut self) -> (W, Result<Vec<u8>, WriterPanicked>) { pub fn into_raw_parts(mut self) -> (W, Result<Vec<u8>, WriterPanicked>) {
let buf = mem::take(&mut self.buf); let buf = mem::take(&mut self.buf);
let buf = if !self.panicked { Ok(buf) } else { Err(WriterPanicked { buf }) }; let buf = if !self.panicked { Ok(buf) } else { Err(WriterPanicked { buf }) };
(self.inner.take().unwrap(), buf)
// SAFETY: forget(self) prevents double dropping inner
let inner = unsafe { ptr::read(&mut self.inner) };
mem::forget(self);
(inner, buf)
} }
// Ensure this function does not get inlined into `write`, so that it // Ensure this function does not get inlined into `write`, so that it
@ -643,7 +647,7 @@ where
{ {
fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result { fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
fmt.debug_struct("BufWriter") fmt.debug_struct("BufWriter")
.field("writer", &self.inner.as_ref().unwrap()) .field("writer", &self.inner)
.field("buffer", &format_args!("{}/{}", self.buf.len(), self.buf.capacity())) .field("buffer", &format_args!("{}/{}", self.buf.len(), self.buf.capacity()))
.finish() .finish()
} }
@ -663,7 +667,7 @@ impl<W: Write + Seek> Seek for BufWriter<W> {
#[stable(feature = "rust1", since = "1.0.0")] #[stable(feature = "rust1", since = "1.0.0")]
impl<W: Write> Drop for BufWriter<W> { impl<W: Write> Drop for BufWriter<W> {
fn drop(&mut self) { fn drop(&mut self) {
if self.inner.is_some() && !self.panicked { if !self.panicked {
// dtors should not panic, so we ignore a failed flush // dtors should not panic, so we ignore a failed flush
let _r = self.flush_buf(); let _r = self.flush_buf();
} }