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stepanchegstepancheg
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Avoid allocations in Debug for os_str
Fixes #38879
1 parent ea149b8 commit ac96fd7

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6 files changed

+117
-35
lines changed

6 files changed

+117
-35
lines changed

Diff for: ‎src/libstd/ffi/os_str.rs

+12-6
Original file line numberDiff line numberDiff line change
@@ -9,7 +9,7 @@
99
// except according to those terms.
1010

1111
use borrow::{Borrow, Cow};
12-
use fmt::{self, Debug};
12+
use fmt;
1313
use mem;
1414
use ops;
1515
use cmp;
@@ -312,8 +312,8 @@ impl Default for OsString {
312312
}
313313

314314
#[stable(feature = "rust1", since = "1.0.0")]
315-
impl Debug for OsString {
316-
fn fmt(&self, formatter: &mut fmt::Formatter) -> Result<(), fmt::Error> {
315+
impl fmt::Debug for OsString {
316+
fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
317317
fmt::Debug::fmt(&**self, formatter)
318318
}
319319
}
@@ -669,9 +669,15 @@ impl Hash for OsStr {
669669
}
670670

671671
#[stable(feature = "rust1", since = "1.0.0")]
672-
impl Debug for OsStr {
673-
fn fmt(&self, formatter: &mut fmt::Formatter) -> Result<(), fmt::Error> {
674-
self.inner.fmt(formatter)
672+
impl fmt::Debug for OsStr {
673+
fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
674+
fmt::Debug::fmt(&self.inner, formatter)
675+
}
676+
}
677+
678+
impl OsStr {
679+
pub(crate) fn display(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
680+
fmt::Display::fmt(&self.inner, formatter)
675681
}
676682
}
677683

Diff for: ‎src/libstd/path.rs

+4-4
Original file line numberDiff line numberDiff line change
@@ -2281,8 +2281,8 @@ impl AsRef<OsStr> for Path {
22812281

22822282
#[stable(feature = "rust1", since = "1.0.0")]
22832283
impl fmt::Debug for Path {
2284-
fn fmt(&self, formatter: &mut fmt::Formatter) -> Result<(), fmt::Error> {
2285-
self.inner.fmt(formatter)
2284+
fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
2285+
fmt::Debug::fmt(&self.inner, formatter)
22862286
}
22872287
}
22882288

@@ -2314,14 +2314,14 @@ pub struct Display<'a> {
23142314
#[stable(feature = "rust1", since = "1.0.0")]
23152315
impl<'a> fmt::Debug for Display<'a> {
23162316
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
2317-
fmt::Debug::fmt(&self.path.to_string_lossy(), f)
2317+
fmt::Debug::fmt(&self.path, f)
23182318
}
23192319
}
23202320

23212321
#[stable(feature = "rust1", since = "1.0.0")]
23222322
impl<'a> fmt::Display for Display<'a> {
23232323
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
2324-
fmt::Display::fmt(&self.path.to_string_lossy(), f)
2324+
self.path.inner.display(f)
23252325
}
23262326
}
23272327

Diff for: ‎src/libstd/sys/redox/os_str.rs

+20-7
Original file line numberDiff line numberDiff line change
@@ -12,10 +12,11 @@
1212
/// a `Vec<u8>`/`[u8]`.
1313
1414
use borrow::Cow;
15-
use fmt::{self, Debug};
15+
use fmt;
1616
use str;
1717
use mem;
1818
use sys_common::{AsInner, IntoInner};
19+
use std_unicode::lossy::Utf8Lossy;
1920

2021
#[derive(Clone, Hash)]
2122
pub struct Buf {
@@ -26,15 +27,27 @@ pub struct Slice {
2627
pub inner: [u8]
2728
}
2829

29-
impl Debug for Slice {
30-
fn fmt(&self, formatter: &mut fmt::Formatter) -> Result<(), fmt::Error> {
31-
self.to_string_lossy().fmt(formatter)
30+
impl fmt::Debug for Slice {
31+
fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
32+
fmt::Debug::fmt(&Utf8Lossy::from_bytes(&self.inner), formatter)
3233
}
3334
}
3435

35-
impl Debug for Buf {
36-
fn fmt(&self, formatter: &mut fmt::Formatter) -> Result<(), fmt::Error> {
37-
self.as_slice().fmt(formatter)
36+
impl fmt::Display for Slice {
37+
fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
38+
fmt::Display::fmt(&Utf8Lossy::from_bytes(&self.inner), formatter)
39+
}
40+
}
41+
42+
impl fmt::Debug for Buf {
43+
fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
44+
fmt::Debug::fmt(self.as_slice(), formatter)
45+
}
46+
}
47+
48+
impl fmt::Display for Buf {
49+
fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
50+
fmt::Display::fmt(self.as_slice(), formatter)
3851
}
3952
}
4053

Diff for: ‎src/libstd/sys/unix/os_str.rs

+20-7
Original file line numberDiff line numberDiff line change
@@ -12,10 +12,11 @@
1212
/// a `Vec<u8>`/`[u8]`.
1313
1414
use borrow::Cow;
15-
use fmt::{self, Debug};
15+
use fmt;
1616
use str;
1717
use mem;
1818
use sys_common::{AsInner, IntoInner};
19+
use std_unicode::lossy::Utf8Lossy;
1920

2021
#[derive(Clone, Hash)]
2122
pub struct Buf {
@@ -26,15 +27,27 @@ pub struct Slice {
2627
pub inner: [u8]
2728
}
2829

29-
impl Debug for Slice {
30-
fn fmt(&self, formatter: &mut fmt::Formatter) -> Result<(), fmt::Error> {
31-
self.to_string_lossy().fmt(formatter)
30+
impl fmt::Debug for Slice {
31+
fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
32+
fmt::Debug::fmt(&Utf8Lossy::from_bytes(&self.inner), formatter)
3233
}
3334
}
3435

35-
impl Debug for Buf {
36-
fn fmt(&self, formatter: &mut fmt::Formatter) -> Result<(), fmt::Error> {
37-
self.as_slice().fmt(formatter)
36+
impl fmt::Display for Slice {
37+
fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
38+
fmt::Display::fmt(&Utf8Lossy::from_bytes(&self.inner), formatter)
39+
}
40+
}
41+
42+
impl fmt::Debug for Buf {
43+
fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
44+
fmt::Debug::fmt(self.as_slice(), formatter)
45+
}
46+
}
47+
48+
impl fmt::Display for Buf {
49+
fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
50+
fmt::Display::fmt(self.as_slice(), formatter)
3851
}
3952
}
4053

Diff for: ‎src/libstd/sys/windows/os_str.rs

+19-7
Original file line numberDiff line numberDiff line change
@@ -12,7 +12,7 @@
1212
/// wrapper around the "WTF-8" encoding; see the `wtf8` module for more.
1313
1414
use borrow::Cow;
15-
use fmt::{self, Debug};
15+
use fmt;
1616
use sys_common::wtf8::{Wtf8, Wtf8Buf};
1717
use mem;
1818
use sys_common::{AsInner, IntoInner};
@@ -34,19 +34,31 @@ impl AsInner<Wtf8> for Buf {
3434
}
3535
}
3636

37-
impl Debug for Buf {
38-
fn fmt(&self, formatter: &mut fmt::Formatter) -> Result<(), fmt::Error> {
39-
self.as_slice().fmt(formatter)
37+
impl fmt::Debug for Buf {
38+
fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
39+
fmt::Debug::fmt(self.as_slice(), formatter)
40+
}
41+
}
42+
43+
impl fmt::Display for Buf {
44+
fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
45+
fmt::Display::fmt(self.as_slice(), formatter)
4046
}
4147
}
4248

4349
pub struct Slice {
4450
pub inner: Wtf8
4551
}
4652

47-
impl Debug for Slice {
48-
fn fmt(&self, formatter: &mut fmt::Formatter) -> Result<(), fmt::Error> {
49-
self.inner.fmt(formatter)
53+
impl fmt::Debug for Slice {
54+
fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
55+
fmt::Debug::fmt(&self.inner, formatter)
56+
}
57+
}
58+
59+
impl fmt::Display for Slice {
60+
fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
61+
fmt::Display::fmt(&self.inner, formatter)
5062
}
5163
}
5264

Diff for: ‎src/libstd/sys_common/wtf8.rs

+42-4
Original file line numberDiff line numberDiff line change
@@ -39,7 +39,7 @@ use slice;
3939
use str;
4040
use sys_common::AsInner;
4141

42-
const UTF8_REPLACEMENT_CHARACTER: &'static [u8] = b"\xEF\xBF\xBD";
42+
const UTF8_REPLACEMENT_CHARACTER: &'static str = "\u{FFFD}";
4343

4444
/// A Unicode code point: from U+0000 to U+10FFFF.
4545
///
@@ -339,7 +339,7 @@ impl Wtf8Buf {
339339
Some((surrogate_pos, _)) => {
340340
pos = surrogate_pos + 3;
341341
self.bytes[surrogate_pos..pos]
342-
.copy_from_slice(UTF8_REPLACEMENT_CHARACTER);
342+
.copy_from_slice(UTF8_REPLACEMENT_CHARACTER.as_bytes());
343343
},
344344
None => return unsafe { String::from_utf8_unchecked(self.bytes) }
345345
}
@@ -438,6 +438,30 @@ impl fmt::Debug for Wtf8 {
438438
}
439439
}
440440

441+
impl fmt::Display for Wtf8 {
442+
fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
443+
let wtf8_bytes = &self.bytes;
444+
let mut pos = 0;
445+
loop {
446+
match self.next_surrogate(pos) {
447+
Some((surrogate_pos, _)) => {
448+
formatter.write_str(unsafe {
449+
str::from_utf8_unchecked(&wtf8_bytes[pos .. surrogate_pos])
450+
})?;
451+
formatter.write_str(UTF8_REPLACEMENT_CHARACTER)?;
452+
pos = surrogate_pos + 3;
453+
},
454+
None => {
455+
formatter.write_str(unsafe {
456+
str::from_utf8_unchecked(&wtf8_bytes[pos..])
457+
})?;
458+
return Ok(());
459+
}
460+
}
461+
}
462+
}
463+
}
464+
441465
impl Wtf8 {
442466
/// Creates a WTF-8 slice from a UTF-8 `&str` slice.
443467
///
@@ -516,13 +540,13 @@ impl Wtf8 {
516540
let wtf8_bytes = &self.bytes;
517541
let mut utf8_bytes = Vec::with_capacity(self.len());
518542
utf8_bytes.extend_from_slice(&wtf8_bytes[..surrogate_pos]);
519-
utf8_bytes.extend_from_slice(UTF8_REPLACEMENT_CHARACTER);
543+
utf8_bytes.extend_from_slice(UTF8_REPLACEMENT_CHARACTER.as_bytes());
520544
let mut pos = surrogate_pos + 3;
521545
loop {
522546
match self.next_surrogate(pos) {
523547
Some((surrogate_pos, _)) => {
524548
utf8_bytes.extend_from_slice(&wtf8_bytes[pos .. surrogate_pos]);
525-
utf8_bytes.extend_from_slice(UTF8_REPLACEMENT_CHARACTER);
549+
utf8_bytes.extend_from_slice(UTF8_REPLACEMENT_CHARACTER.as_bytes());
526550
pos = surrogate_pos + 3;
527551
},
528552
None => {
@@ -1200,6 +1224,20 @@ mod tests {
12001224
assert_eq!(string.to_string_lossy(), expected);
12011225
}
12021226

1227+
#[test]
1228+
fn wtf8_display() {
1229+
fn d(b: &[u8]) -> String {
1230+
format!("{}", &unsafe { Wtf8::from_bytes_unchecked(b) })
1231+
}
1232+
1233+
assert_eq!("", d("".as_bytes()));
1234+
assert_eq!("aé 💩", d("aé 💩".as_bytes()));
1235+
1236+
let mut string = Wtf8Buf::from_str("aé 💩");
1237+
string.push(CodePoint::from_u32(0xD800).unwrap());
1238+
assert_eq!("aé 💩�", d(string.as_inner()));
1239+
}
1240+
12031241
#[test]
12041242
fn wtf8_encode_wide() {
12051243
let mut string = Wtf8Buf::from_str("aé ");

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