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Add the Layout of the failed allocation to TryReserveError::AllocError

… and add a separately-unstable field to force non-exhaustive matching
(`#[non_exhaustive]` is no implemented yet on enum variants)
so that we have the option to later expose the allocator’s error value.

CC rust-lang/wg-allocators#23
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SimonSapin committed Jun 12, 2019
1 parent a92c29b commit 59a340963fa5d8b5507d95cd015f7ca2855ba151
@@ -41,25 +41,28 @@ pub use linked_list::LinkedList;
#[doc(no_inline)]
pub use vec_deque::VecDeque;

use crate::alloc::{AllocErr, LayoutErr};
use crate::alloc::{Layout, LayoutErr};

/// Augments `AllocErr` with a CapacityOverflow variant.
/// The error type for `try_reserve` methods.
#[derive(Clone, PartialEq, Eq, Debug)]
#[unstable(feature = "try_reserve", reason = "new API", issue="48043")]
pub enum TryReserveError {
/// Error due to the computed capacity exceeding the collection's maximum
/// (usually `isize::MAX` bytes).
CapacityOverflow,
/// Error due to the allocator (see the `AllocErr` type's docs).
AllocErr,
}

#[unstable(feature = "try_reserve", reason = "new API", issue="48043")]
impl From<AllocErr> for TryReserveError {
#[inline]
fn from(AllocErr: AllocErr) -> Self {
TryReserveError::AllocErr
}
/// The memory allocator returned an error
AllocError {
/// The layout of allocation request that failed
layout: Layout,

#[doc(hidden)]
#[unstable(feature = "container_error_extra", issue = "0", reason = "\
Enable exposing the allocator’s custom error value \
if an associated type is added in the future: \
https://github.com/rust-lang/wg-allocators/issues/23")]
non_exhaustive: (),
},
}

#[unstable(feature = "try_reserve", reason = "new API", issue="48043")]
@@ -87,6 +87,7 @@
#![feature(const_in_array_repeat_expressions)]
#![feature(dispatch_from_dyn)]
#![feature(core_intrinsics)]
#![feature(container_error_extra)]
#![feature(dropck_eyepatch)]
#![feature(exact_size_is_empty)]
#![feature(fmt_internals)]
@@ -7,7 +7,7 @@ use core::ops::Drop;
use core::ptr::{self, NonNull, Unique};
use core::slice;

use crate::alloc::{Alloc, Layout, Global, handle_alloc_error};
use crate::alloc::{Alloc, Layout, Global, AllocErr, handle_alloc_error};
use crate::collections::TryReserveError::{self, *};
use crate::boxed::Box;

@@ -413,7 +413,7 @@ impl<T, A: Alloc> RawVec<T, A> {
pub fn reserve_exact(&mut self, used_capacity: usize, needed_extra_capacity: usize) {
match self.reserve_internal(used_capacity, needed_extra_capacity, Infallible, Exact) {
Err(CapacityOverflow) => capacity_overflow(),
Err(AllocErr) => unreachable!(),
Err(AllocError { .. }) => unreachable!(),
Ok(()) => { /* yay */ }
}
}
@@ -494,7 +494,7 @@ impl<T, A: Alloc> RawVec<T, A> {
pub fn reserve(&mut self, used_capacity: usize, needed_extra_capacity: usize) {
match self.reserve_internal(used_capacity, needed_extra_capacity, Infallible, Amortized) {
Err(CapacityOverflow) => capacity_overflow(),
Err(AllocErr) => unreachable!(),
Err(AllocError { .. }) => unreachable!(),
Ok(()) => { /* yay */ }
}
}
@@ -642,8 +642,6 @@ impl<T, A: Alloc> RawVec<T, A> {
strategy: ReserveStrategy,
) -> Result<(), TryReserveError> {
unsafe {
use crate::alloc::AllocErr;

// NOTE: we don't early branch on ZSTs here because we want this
// to actually catch "asking for more than usize::MAX" in that case.
// If we make it past the first branch then we are guaranteed to
@@ -672,12 +670,16 @@ impl<T, A: Alloc> RawVec<T, A> {
None => self.a.alloc(new_layout),
};

match (&res, fallibility) {
let ptr = match (res, fallibility) {
(Err(AllocErr), Infallible) => handle_alloc_error(new_layout),
_ => {}
}
(Err(AllocErr), Fallible) => return Err(TryReserveError::AllocError {
layout: new_layout,
non_exhaustive: (),
}),
(Ok(ptr), _) => ptr,
};

self.ptr = res?.cast().into();
self.ptr = ptr.cast().into();
self.cap = new_cap;

Ok(())
@@ -566,11 +566,11 @@ fn test_try_reserve() {
} else { panic!("usize::MAX should trigger an overflow!") }
} else {
// Check isize::MAX + 1 is an OOM
if let Err(AllocErr) = empty_string.try_reserve(MAX_CAP + 1) {
if let Err(AllocError { .. }) = empty_string.try_reserve(MAX_CAP + 1) {
} else { panic!("isize::MAX + 1 should trigger an OOM!") }

// Check usize::MAX is an OOM
if let Err(AllocErr) = empty_string.try_reserve(MAX_USIZE) {
if let Err(AllocError { .. }) = empty_string.try_reserve(MAX_USIZE) {
} else { panic!("usize::MAX should trigger an OOM!") }
}
}
@@ -590,7 +590,7 @@ fn test_try_reserve() {
if let Err(CapacityOverflow) = ten_bytes.try_reserve(MAX_CAP - 9) {
} else { panic!("isize::MAX + 1 should trigger an overflow!"); }
} else {
if let Err(AllocErr) = ten_bytes.try_reserve(MAX_CAP - 9) {
if let Err(AllocError { .. }) = ten_bytes.try_reserve(MAX_CAP - 9) {
} else { panic!("isize::MAX + 1 should trigger an OOM!") }
}
// Should always overflow in the add-to-len
@@ -629,10 +629,10 @@ fn test_try_reserve_exact() {
if let Err(CapacityOverflow) = empty_string.try_reserve_exact(MAX_USIZE) {
} else { panic!("usize::MAX should trigger an overflow!") }
} else {
if let Err(AllocErr) = empty_string.try_reserve_exact(MAX_CAP + 1) {
if let Err(AllocError { .. }) = empty_string.try_reserve_exact(MAX_CAP + 1) {
} else { panic!("isize::MAX + 1 should trigger an OOM!") }

if let Err(AllocErr) = empty_string.try_reserve_exact(MAX_USIZE) {
if let Err(AllocError { .. }) = empty_string.try_reserve_exact(MAX_USIZE) {
} else { panic!("usize::MAX should trigger an OOM!") }
}
}
@@ -651,7 +651,7 @@ fn test_try_reserve_exact() {
if let Err(CapacityOverflow) = ten_bytes.try_reserve_exact(MAX_CAP - 9) {
} else { panic!("isize::MAX + 1 should trigger an overflow!"); }
} else {
if let Err(AllocErr) = ten_bytes.try_reserve_exact(MAX_CAP - 9) {
if let Err(AllocError { .. }) = ten_bytes.try_reserve_exact(MAX_CAP - 9) {
} else { panic!("isize::MAX + 1 should trigger an OOM!") }
}
if let Err(CapacityOverflow) = ten_bytes.try_reserve_exact(MAX_USIZE) {
@@ -1121,11 +1121,11 @@ fn test_try_reserve() {
} else { panic!("usize::MAX should trigger an overflow!") }
} else {
// Check isize::MAX + 1 is an OOM
if let Err(AllocErr) = empty_bytes.try_reserve(MAX_CAP + 1) {
if let Err(AllocError { .. }) = empty_bytes.try_reserve(MAX_CAP + 1) {
} else { panic!("isize::MAX + 1 should trigger an OOM!") }

// Check usize::MAX is an OOM
if let Err(AllocErr) = empty_bytes.try_reserve(MAX_USIZE) {
if let Err(AllocError { .. }) = empty_bytes.try_reserve(MAX_USIZE) {
} else { panic!("usize::MAX should trigger an OOM!") }
}
}
@@ -1145,7 +1145,7 @@ fn test_try_reserve() {
if let Err(CapacityOverflow) = ten_bytes.try_reserve(MAX_CAP - 9) {
} else { panic!("isize::MAX + 1 should trigger an overflow!"); }
} else {
if let Err(AllocErr) = ten_bytes.try_reserve(MAX_CAP - 9) {
if let Err(AllocError { .. }) = ten_bytes.try_reserve(MAX_CAP - 9) {
} else { panic!("isize::MAX + 1 should trigger an OOM!") }
}
// Should always overflow in the add-to-len
@@ -1168,7 +1168,7 @@ fn test_try_reserve() {
if let Err(CapacityOverflow) = ten_u32s.try_reserve(MAX_CAP/4 - 9) {
} else { panic!("isize::MAX + 1 should trigger an overflow!"); }
} else {
if let Err(AllocErr) = ten_u32s.try_reserve(MAX_CAP/4 - 9) {
if let Err(AllocError { .. }) = ten_u32s.try_reserve(MAX_CAP/4 - 9) {
} else { panic!("isize::MAX + 1 should trigger an OOM!") }
}
// Should fail in the mul-by-size
@@ -1209,10 +1209,10 @@ fn test_try_reserve_exact() {
if let Err(CapacityOverflow) = empty_bytes.try_reserve_exact(MAX_USIZE) {
} else { panic!("usize::MAX should trigger an overflow!") }
} else {
if let Err(AllocErr) = empty_bytes.try_reserve_exact(MAX_CAP + 1) {
if let Err(AllocError { .. }) = empty_bytes.try_reserve_exact(MAX_CAP + 1) {
} else { panic!("isize::MAX + 1 should trigger an OOM!") }

if let Err(AllocErr) = empty_bytes.try_reserve_exact(MAX_USIZE) {
if let Err(AllocError { .. }) = empty_bytes.try_reserve_exact(MAX_USIZE) {
} else { panic!("usize::MAX should trigger an OOM!") }
}
}
@@ -1231,7 +1231,7 @@ fn test_try_reserve_exact() {
if let Err(CapacityOverflow) = ten_bytes.try_reserve_exact(MAX_CAP - 9) {
} else { panic!("isize::MAX + 1 should trigger an overflow!"); }
} else {
if let Err(AllocErr) = ten_bytes.try_reserve_exact(MAX_CAP - 9) {
if let Err(AllocError { .. }) = ten_bytes.try_reserve_exact(MAX_CAP - 9) {
} else { panic!("isize::MAX + 1 should trigger an OOM!") }
}
if let Err(CapacityOverflow) = ten_bytes.try_reserve_exact(MAX_USIZE) {
@@ -1252,7 +1252,7 @@ fn test_try_reserve_exact() {
if let Err(CapacityOverflow) = ten_u32s.try_reserve_exact(MAX_CAP/4 - 9) {
} else { panic!("isize::MAX + 1 should trigger an overflow!"); }
} else {
if let Err(AllocErr) = ten_u32s.try_reserve_exact(MAX_CAP/4 - 9) {
if let Err(AllocError { .. }) = ten_u32s.try_reserve_exact(MAX_CAP/4 - 9) {
} else { panic!("isize::MAX + 1 should trigger an OOM!") }
}
if let Err(CapacityOverflow) = ten_u32s.try_reserve_exact(MAX_USIZE - 20) {
@@ -1168,7 +1168,7 @@ fn test_try_reserve() {
// VecDeque starts with capacity 7, always adds 1 to the capacity
// and also rounds the number to next power of 2 so this is the
// furthest we can go without triggering CapacityOverflow
if let Err(AllocErr) = empty_bytes.try_reserve(MAX_CAP) {
if let Err(AllocError { .. }) = empty_bytes.try_reserve(MAX_CAP) {
} else { panic!("isize::MAX + 1 should trigger an OOM!") }
}
}
@@ -1188,7 +1188,7 @@ fn test_try_reserve() {
if let Err(CapacityOverflow) = ten_bytes.try_reserve(MAX_CAP - 9) {
} else { panic!("isize::MAX + 1 should trigger an overflow!"); }
} else {
if let Err(AllocErr) = ten_bytes.try_reserve(MAX_CAP - 9) {
if let Err(AllocError { .. }) = ten_bytes.try_reserve(MAX_CAP - 9) {
} else { panic!("isize::MAX + 1 should trigger an OOM!") }
}
// Should always overflow in the add-to-len
@@ -1211,7 +1211,7 @@ fn test_try_reserve() {
if let Err(CapacityOverflow) = ten_u32s.try_reserve(MAX_CAP/4 - 9) {
} else { panic!("isize::MAX + 1 should trigger an overflow!"); }
} else {
if let Err(AllocErr) = ten_u32s.try_reserve(MAX_CAP/4 - 9) {
if let Err(AllocError { .. }) = ten_u32s.try_reserve(MAX_CAP/4 - 9) {
} else { panic!("isize::MAX + 1 should trigger an OOM!") }
}
// Should fail in the mul-by-size
@@ -1256,7 +1256,7 @@ fn test_try_reserve_exact() {
// VecDeque starts with capacity 7, always adds 1 to the capacity
// and also rounds the number to next power of 2 so this is the
// furthest we can go without triggering CapacityOverflow
if let Err(AllocErr) = empty_bytes.try_reserve_exact(MAX_CAP) {
if let Err(AllocError { .. }) = empty_bytes.try_reserve_exact(MAX_CAP) {
} else { panic!("isize::MAX + 1 should trigger an OOM!") }
}
}
@@ -1275,7 +1275,7 @@ fn test_try_reserve_exact() {
if let Err(CapacityOverflow) = ten_bytes.try_reserve_exact(MAX_CAP - 9) {
} else { panic!("isize::MAX + 1 should trigger an overflow!"); }
} else {
if let Err(AllocErr) = ten_bytes.try_reserve_exact(MAX_CAP - 9) {
if let Err(AllocError { .. }) = ten_bytes.try_reserve_exact(MAX_CAP - 9) {
} else { panic!("isize::MAX + 1 should trigger an OOM!") }
}
if let Err(CapacityOverflow) = ten_bytes.try_reserve_exact(MAX_USIZE) {
@@ -1296,7 +1296,7 @@ fn test_try_reserve_exact() {
if let Err(CapacityOverflow) = ten_u32s.try_reserve_exact(MAX_CAP/4 - 9) {
} else { panic!("isize::MAX + 1 should trigger an overflow!"); }
} else {
if let Err(AllocErr) = ten_u32s.try_reserve_exact(MAX_CAP/4 - 9) {
if let Err(AllocError { .. }) = ten_u32s.try_reserve_exact(MAX_CAP/4 - 9) {
} else { panic!("isize::MAX + 1 should trigger an OOM!") }
}
if let Err(CapacityOverflow) = ten_u32s.try_reserve_exact(MAX_USIZE - 20) {
@@ -2545,7 +2545,10 @@ fn map_entry<'a, K: 'a, V: 'a>(raw: base::RustcEntry<'a, K, V>) -> Entry<'a, K,
fn map_collection_alloc_err(err: hashbrown::CollectionAllocErr) -> TryReserveError {
match err {
hashbrown::CollectionAllocErr::CapacityOverflow => TryReserveError::CapacityOverflow,
hashbrown::CollectionAllocErr::AllocErr { .. } => TryReserveError::AllocErr,
hashbrown::CollectionAllocErr::AllocErr { layout } => TryReserveError::AllocError {
layout,
non_exhaustive: (),
},
}
}

@@ -3405,7 +3408,7 @@ mod test_map {
panic!("usize::MAX should trigger an overflow!");
}

if let Err(AllocErr) = empty_bytes.try_reserve(MAX_USIZE / 8) {
if let Err(AllocError { .. }) = empty_bytes.try_reserve(MAX_USIZE / 8) {
} else {
panic!("usize::MAX / 8 should trigger an OOM!")
}
@@ -251,6 +251,7 @@
#![feature(concat_idents)]
#![feature(const_cstr_unchecked)]
#![feature(const_raw_ptr_deref)]
#![feature(container_error_extra)]
#![feature(core_intrinsics)]
#![feature(custom_test_frameworks)]
#![feature(doc_alias)]

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