diff options
Diffstat (limited to '')
| -rw-r--r-- | third_party/rust/atomic/.cargo-checksum.json | 1 | ||||
| -rw-r--r-- | third_party/rust/atomic/Cargo.toml | 26 | ||||
| -rw-r--r-- | third_party/rust/atomic/LICENSE-APACHE | 201 | ||||
| -rw-r--r-- | third_party/rust/atomic/LICENSE-MIT | 25 | ||||
| -rw-r--r-- | third_party/rust/atomic/README.md | 51 | ||||
| -rw-r--r-- | third_party/rust/atomic/src/fallback.rs | 196 | ||||
| -rw-r--r-- | third_party/rust/atomic/src/lib.rs | 735 | ||||
| -rw-r--r-- | third_party/rust/atomic/src/ops.rs | 666 | ||||
| -rw-r--r-- | third_party/rust/atomic_refcell/.cargo-checksum.json | 1 | ||||
| -rw-r--r-- | third_party/rust/atomic_refcell/Cargo.toml | 21 | ||||
| -rw-r--r-- | third_party/rust/atomic_refcell/README.md | 2 | ||||
| -rw-r--r-- | third_party/rust/atomic_refcell/benches/basic.rs | 37 | ||||
| -rw-r--r-- | third_party/rust/atomic_refcell/src/lib.rs | 486 | ||||
| -rw-r--r-- | third_party/rust/atomic_refcell/tests/basic.rs | 156 |
14 files changed, 2604 insertions, 0 deletions
diff --git a/third_party/rust/atomic/.cargo-checksum.json b/third_party/rust/atomic/.cargo-checksum.json new file mode 100644 index 0000000000..9410ca648a --- /dev/null +++ b/third_party/rust/atomic/.cargo-checksum.json @@ -0,0 +1 @@ +{"files":{"Cargo.toml":"811d9a1badcf5b916dfb9be29473760b368750e94790dec636665ff4f07f43a7","LICENSE-APACHE":"a60eea817514531668d7e00765731449fe14d059d3249e0bc93b36de45f759f2","LICENSE-MIT":"c9a75f18b9ab2927829a208fc6aa2cf4e63b8420887ba29cdb265d6619ae82d5","README.md":"c45110524352e139b2d7de30ae225d098d3e016cabb66fcc4a90c790ebcb1c3c","src/fallback.rs":"ef3172236b690c8bb88d307c7a33c898420ea34c8a5ad5025f0e3eb3cef2b4f5","src/lib.rs":"bbbf586ec7e2e5e54863fd3f2bdfbf5b2a2a6c179cf6df228635163a2592c89f","src/ops.rs":"884549e2c4163fc9e3e383fa007db5aad872d8e4c99680e6c6bf48806cd26390"},"package":"64f46ca51dca4837f1520754d1c8c36636356b81553d928dc9c177025369a06e"}
\ No newline at end of file diff --git a/third_party/rust/atomic/Cargo.toml b/third_party/rust/atomic/Cargo.toml new file mode 100644 index 0000000000..cc7531f90e --- /dev/null +++ b/third_party/rust/atomic/Cargo.toml @@ -0,0 +1,26 @@ +# THIS FILE IS AUTOMATICALLY GENERATED BY CARGO +# +# When uploading crates to the registry Cargo will automatically +# "normalize" Cargo.toml files for maximal compatibility +# with all versions of Cargo and also rewrite `path` dependencies +# to registry (e.g., crates.io) dependencies +# +# If you believe there's an error in this file please file an +# issue against the rust-lang/cargo repository. If you're +# editing this file be aware that the upstream Cargo.toml +# will likely look very different (and much more reasonable) + +[package] +name = "atomic" +version = "0.4.6" +authors = ["Amanieu d'Antras <amanieu@gmail.com>"] +description = "Generic Atomic<T> wrapper type" +documentation = "https://amanieu.github.io/atomic-rs/atomic/index.html" +readme = "README.md" +keywords = ["atomic", "no_std"] +license = "Apache-2.0/MIT" +repository = "https://github.com/Amanieu/atomic-rs" + +[features] +nightly = [] +std = [] diff --git a/third_party/rust/atomic/LICENSE-APACHE b/third_party/rust/atomic/LICENSE-APACHE new file mode 100644 index 0000000000..16fe87b06e --- /dev/null +++ b/third_party/rust/atomic/LICENSE-APACHE @@ -0,0 +1,201 @@ + Apache License + Version 2.0, January 2004 + http://www.apache.org/licenses/ + +TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION + +1. Definitions. + + "License" shall mean the terms and conditions for use, reproduction, + and distribution as defined by Sections 1 through 9 of this document. + + "Licensor" shall mean the copyright owner or entity authorized by + the copyright owner that is granting the License. + + "Legal Entity" shall mean the union of the acting entity and all + other entities that control, are controlled by, or are under common + control with that entity. For the purposes of this definition, + "control" means (i) the power, direct or indirect, to cause the + direction or management of such entity, whether by contract or + otherwise, or (ii) ownership of fifty percent (50%) or more of the + outstanding shares, or (iii) beneficial ownership of such entity. + + "You" (or "Your") shall mean an individual or Legal Entity + exercising permissions granted by this License. + + "Source" form shall mean the preferred form for making modifications, + including but not limited to software source code, documentation + source, and configuration files. + + "Object" form shall mean any form resulting from mechanical + transformation or translation of a Source form, including but + not limited to compiled object code, generated documentation, + and conversions to other media types. + + "Work" shall mean the work of authorship, whether in Source or + Object form, made available under the License, as indicated by a + copyright notice that is included in or attached to the work + (an example is provided in the Appendix below). + + "Derivative Works" shall mean any work, whether in Source or Object + form, that is based on (or derived from) the Work and for which the + editorial revisions, annotations, elaborations, or other modifications + represent, as a whole, an original work of authorship. For the purposes + of this License, Derivative Works shall not include works that remain + separable from, or merely link (or bind by name) to the interfaces of, + the Work and Derivative Works thereof. + + "Contribution" shall mean any work of authorship, including + the original version of the Work and any modifications or additions + to that Work or Derivative Works thereof, that is intentionally + submitted to Licensor for inclusion in the Work by the copyright owner + or by an individual or Legal Entity authorized to submit on behalf of + the copyright owner. For the purposes of this definition, "submitted" + means any form of electronic, verbal, or written communication sent + to the Licensor or its representatives, including but not limited to + communication on electronic mailing lists, source code control systems, + and issue tracking systems that are managed by, or on behalf of, the + Licensor for the purpose of discussing and improving the Work, but + excluding communication that is conspicuously marked or otherwise + designated in writing by the copyright owner as "Not a Contribution." + + "Contributor" shall mean Licensor and any individual or Legal Entity + on behalf of whom a Contribution has been received by Licensor and + subsequently incorporated within the Work. + +2. Grant of Copyright License. Subject to the terms and conditions of + this License, each Contributor hereby grants to You a perpetual, + worldwide, non-exclusive, no-charge, royalty-free, irrevocable + copyright license to reproduce, prepare Derivative Works of, + publicly display, publicly perform, sublicense, and distribute the + Work and such Derivative Works in Source or Object form. + +3. Grant of Patent License. Subject to the terms and conditions of + this License, each Contributor hereby grants to You a perpetual, + worldwide, non-exclusive, no-charge, royalty-free, irrevocable + (except as stated in this section) patent license to make, have made, + use, offer to sell, sell, import, and otherwise transfer the Work, + where such license applies only to those patent claims licensable + by such Contributor that are necessarily infringed by their + Contribution(s) alone or by combination of their Contribution(s) + with the Work to which such Contribution(s) was submitted. If You + institute patent litigation against any entity (including a + cross-claim or counterclaim in a lawsuit) alleging that the Work + or a Contribution incorporated within the Work constitutes direct + or contributory patent infringement, then any patent licenses + granted to You under this License for that Work shall terminate + as of the date such litigation is filed. + +4. Redistribution. You may reproduce and distribute copies of the + Work or Derivative Works thereof in any medium, with or without + modifications, and in Source or Object form, provided that You + meet the following conditions: + + (a) You must give any other recipients of the Work or + Derivative Works a copy of this License; and + + (b) You must cause any modified files to carry prominent notices + stating that You changed the files; and + + (c) You must retain, in the Source form of any Derivative Works + that You distribute, all copyright, patent, trademark, and + attribution notices from the Source form of the Work, + excluding those notices that do not pertain to any part of + the Derivative Works; and + + (d) If the Work includes a "NOTICE" text file as part of its + distribution, then any Derivative Works that You distribute must + include a readable copy of the attribution notices contained + within such NOTICE file, excluding those notices that do not + pertain to any part of the Derivative Works, in at least one + of the following places: within a NOTICE text file distributed + as part of the Derivative Works; within the Source form or + documentation, if provided along with the Derivative Works; or, + within a display generated by the Derivative Works, if and + wherever such third-party notices normally appear. The contents + of the NOTICE file are for informational purposes only and + do not modify the License. You may add Your own attribution + notices within Derivative Works that You distribute, alongside + or as an addendum to the NOTICE text from the Work, provided + that such additional attribution notices cannot be construed + as modifying the License. + + You may add Your own copyright statement to Your modifications and + may provide additional or different license terms and conditions + for use, reproduction, or distribution of Your modifications, or + for any such Derivative Works as a whole, provided Your use, + reproduction, and distribution of the Work otherwise complies with + the conditions stated in this License. + +5. Submission of Contributions. Unless You explicitly state otherwise, + any Contribution intentionally submitted for inclusion in the Work + by You to the Licensor shall be under the terms and conditions of + this License, without any additional terms or conditions. + Notwithstanding the above, nothing herein shall supersede or modify + the terms of any separate license agreement you may have executed + with Licensor regarding such Contributions. + +6. Trademarks. This License does not grant permission to use the trade + names, trademarks, service marks, or product names of the Licensor, + except as required for reasonable and customary use in describing the + origin of the Work and reproducing the content of the NOTICE file. + +7. Disclaimer of Warranty. Unless required by applicable law or + agreed to in writing, Licensor provides the Work (and each + Contributor provides its Contributions) on an "AS IS" BASIS, + WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or + implied, including, without limitation, any warranties or conditions + of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A + PARTICULAR PURPOSE. You are solely responsible for determining the + appropriateness of using or redistributing the Work and assume any + risks associated with Your exercise of permissions under this License. + +8. Limitation of Liability. In no event and under no legal theory, + whether in tort (including negligence), contract, or otherwise, + unless required by applicable law (such as deliberate and grossly + negligent acts) or agreed to in writing, shall any Contributor be + liable to You for damages, including any direct, indirect, special, + incidental, or consequential damages of any character arising as a + result of this License or out of the use or inability to use the + Work (including but not limited to damages for loss of goodwill, + work stoppage, computer failure or malfunction, or any and all + other commercial damages or losses), even if such Contributor + has been advised of the possibility of such damages. + +9. Accepting Warranty or Additional Liability. While redistributing + the Work or Derivative Works thereof, You may choose to offer, + and charge a fee for, acceptance of support, warranty, indemnity, + or other liability obligations and/or rights consistent with this + License. However, in accepting such obligations, You may act only + on Your own behalf and on Your sole responsibility, not on behalf + of any other Contributor, and only if You agree to indemnify, + defend, and hold each Contributor harmless for any liability + incurred by, or claims asserted against, such Contributor by reason + of your accepting any such warranty or additional liability. + +END OF TERMS AND CONDITIONS + +APPENDIX: How to apply the Apache License to your work. + + To apply the Apache License to your work, attach the following + boilerplate notice, with the fields enclosed by brackets "[]" + replaced with your own identifying information. (Don't include + the brackets!) The text should be enclosed in the appropriate + comment syntax for the file format. We also recommend that a + file or class name and description of purpose be included on the + same "printed page" as the copyright notice for easier + identification within third-party archives. + +Copyright [yyyy] [name of copyright owner] + +Licensed under the Apache License, Version 2.0 (the "License"); +you may not use this file except in compliance with the License. +You may obtain a copy of the License at + + http://www.apache.org/licenses/LICENSE-2.0 + +Unless required by applicable law or agreed to in writing, software +distributed under the License is distributed on an "AS IS" BASIS, +WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +See the License for the specific language governing permissions and +limitations under the License. diff --git a/third_party/rust/atomic/LICENSE-MIT b/third_party/rust/atomic/LICENSE-MIT new file mode 100644 index 0000000000..40b8817a47 --- /dev/null +++ b/third_party/rust/atomic/LICENSE-MIT @@ -0,0 +1,25 @@ +Copyright (c) 2016 The Rust Project Developers + +Permission is hereby granted, free of charge, to any +person obtaining a copy of this software and associated +documentation files (the "Software"), to deal in the +Software without restriction, including without +limitation the rights to use, copy, modify, merge, +publish, distribute, sublicense, and/or sell copies of +the Software, and to permit persons to whom the Software +is furnished to do so, subject to the following +conditions: + +The above copyright notice and this permission notice +shall be included in all copies or substantial portions +of the Software. + +THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF +ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED +TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A +PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT +SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY +CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION +OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR +IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER +DEALINGS IN THE SOFTWARE. diff --git a/third_party/rust/atomic/README.md b/third_party/rust/atomic/README.md new file mode 100644 index 0000000000..7b122167bf --- /dev/null +++ b/third_party/rust/atomic/README.md @@ -0,0 +1,51 @@ +Generic `Atomic<T>` for Rust +============================ + +[](https://travis-ci.org/Amanieu/atomic-rs) [](https://crates.io/crates/atomic) + +A Rust library which provides a generic `Atomic<T>` type for all `T: Copy` types, unlike the standard library which only provides a few fixed atomic types (`AtomicBool`, `AtomicIsize`, `AtomicUsize`, `AtomicPtr`). + +This library will use native atomic instructions if possible, and will otherwise fall back to a lock-based mechanism. You can use the `Atomic::<T>::is_lock_free()` function to check whether native atomic operations are supported for a given type. Note that a type must have a power-of-2 size and alignment in order to be used by native atomic instructions. + +Only a subset of native atomic operations are supported on stable Rust (types which are the same size as `AtomicUsize`), but you can use the `nightly` Cargo feature on a nightly compiler to enable the full range of native atomic instructions. The `nightly` feature also enables `const fn` constructors which allow you to initialize static atomic variables. + +This crate uses `#![no_std]` and only depends on libcore. + +[Documentation](https://amanieu.github.io/atomic-rs/atomic/index.html) + +## Usage + +Add this to your `Cargo.toml`: + +```toml +[dependencies] +atomic = "0.4" +``` + +and this to your crate root: + +```rust +extern crate atomic; +``` + +To enable nightly-only features, add this to your `Cargo.toml` instead: + +```toml +[dependencies] +atomic = {version = "0.4", features = ["nightly"]} +``` + +## License + +Licensed under either of + + * Apache License, Version 2.0, ([LICENSE-APACHE](LICENSE-APACHE) or http://www.apache.org/licenses/LICENSE-2.0) + * MIT license ([LICENSE-MIT](LICENSE-MIT) or http://opensource.org/licenses/MIT) + +at your option. + +### Contribution + +Unless you explicitly state otherwise, any contribution intentionally submitted +for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any +additional terms or conditions. diff --git a/third_party/rust/atomic/src/fallback.rs b/third_party/rust/atomic/src/fallback.rs new file mode 100644 index 0000000000..8b7e86119b --- /dev/null +++ b/third_party/rust/atomic/src/fallback.rs @@ -0,0 +1,196 @@ +// Copyright 2016 Amanieu d'Antras +// +// Licensed under the Apache License, Version 2.0, <LICENSE-APACHE or +// http://apache.org/licenses/LICENSE-2.0> or the MIT license <LICENSE-MIT or +// http://opensource.org/licenses/MIT>, at your option. This file may not be +// copied, modified, or distributed except according to those terms. + +use core::cmp; +use core::mem; +use core::num::Wrapping; +use core::ops; +use core::ptr; +use core::slice; +use core::sync::atomic::{self, AtomicUsize, Ordering}; + +// We use an AtomicUsize instead of an AtomicBool because it performs better +// on architectures that don't have byte-sized atomics. +// +// We give each spinlock its own cache line to avoid false sharing. +#[repr(align(64))] +struct SpinLock(AtomicUsize); + +impl SpinLock { + fn lock(&self) { + while self + .0 + .compare_exchange_weak(0, 1, Ordering::Acquire, Ordering::Relaxed) + .is_err() + { + while self.0.load(Ordering::Relaxed) != 0 { + atomic::spin_loop_hint(); + } + } + } + + fn unlock(&self) { + self.0.store(0, Ordering::Release); + } +} + +// A big array of spinlocks which we use to guard atomic accesses. A spinlock is +// chosen based on a hash of the address of the atomic object, which helps to +// reduce contention compared to a single global lock. +macro_rules! array { + (@accum (0, $($_es:expr),*) -> ($($body:tt)*)) + => {array!(@as_expr [$($body)*])}; + (@accum (1, $($es:expr),*) -> ($($body:tt)*)) + => {array!(@accum (0, $($es),*) -> ($($body)* $($es,)*))}; + (@accum (2, $($es:expr),*) -> ($($body:tt)*)) + => {array!(@accum (0, $($es),*) -> ($($body)* $($es,)* $($es,)*))}; + (@accum (4, $($es:expr),*) -> ($($body:tt)*)) + => {array!(@accum (2, $($es,)* $($es),*) -> ($($body)*))}; + (@accum (8, $($es:expr),*) -> ($($body:tt)*)) + => {array!(@accum (4, $($es,)* $($es),*) -> ($($body)*))}; + (@accum (16, $($es:expr),*) -> ($($body:tt)*)) + => {array!(@accum (8, $($es,)* $($es),*) -> ($($body)*))}; + (@accum (32, $($es:expr),*) -> ($($body:tt)*)) + => {array!(@accum (16, $($es,)* $($es),*) -> ($($body)*))}; + (@accum (64, $($es:expr),*) -> ($($body:tt)*)) + => {array!(@accum (32, $($es,)* $($es),*) -> ($($body)*))}; + + (@as_expr $e:expr) => {$e}; + + [$e:expr; $n:tt] => { array!(@accum ($n, $e) -> ()) }; +} +static SPINLOCKS: [SpinLock; 64] = array![SpinLock(AtomicUsize::new(0)); 64]; + +// Spinlock pointer hashing function from compiler-rt +#[inline] +fn lock_for_addr(addr: usize) -> &'static SpinLock { + // Disregard the lowest 4 bits. We want all values that may be part of the + // same memory operation to hash to the same value and therefore use the same + // lock. + let mut hash = addr >> 4; + // Use the next bits as the basis for the hash + let low = hash & (SPINLOCKS.len() - 1); + // Now use the high(er) set of bits to perturb the hash, so that we don't + // get collisions from atomic fields in a single object + hash >>= 16; + hash ^= low; + // Return a pointer to the lock to use + &SPINLOCKS[hash & (SPINLOCKS.len() - 1)] +} + +#[inline] +fn lock(addr: usize) -> LockGuard { + let lock = lock_for_addr(addr); + lock.lock(); + LockGuard(lock) +} + +struct LockGuard(&'static SpinLock); +impl Drop for LockGuard { + #[inline] + fn drop(&mut self) { + self.0.unlock(); + } +} + +#[inline] +pub unsafe fn atomic_load<T>(dst: *mut T) -> T { + let _l = lock(dst as usize); + ptr::read(dst) +} + +#[inline] +pub unsafe fn atomic_store<T>(dst: *mut T, val: T) { + let _l = lock(dst as usize); + ptr::write(dst, val); +} + +#[inline] +pub unsafe fn atomic_swap<T>(dst: *mut T, val: T) -> T { + let _l = lock(dst as usize); + ptr::replace(dst, val) +} + +#[inline] +pub unsafe fn atomic_compare_exchange<T>(dst: *mut T, current: T, new: T) -> Result<T, T> { + let _l = lock(dst as usize); + let result = ptr::read(dst); + // compare_exchange compares with memcmp instead of Eq + let a = slice::from_raw_parts(&result as *const _ as *const u8, mem::size_of_val(&result)); + let b = slice::from_raw_parts( + ¤t as *const _ as *const u8, + mem::size_of_val(¤t), + ); + if a == b { + ptr::write(dst, new); + Ok(result) + } else { + Err(result) + } +} + +#[inline] +pub unsafe fn atomic_add<T: Copy>(dst: *mut T, val: T) -> T +where + Wrapping<T>: ops::Add<Output = Wrapping<T>>, +{ + let _l = lock(dst as usize); + let result = ptr::read(dst); + ptr::write(dst, (Wrapping(result) + Wrapping(val)).0); + result +} + +#[inline] +pub unsafe fn atomic_sub<T: Copy>(dst: *mut T, val: T) -> T +where + Wrapping<T>: ops::Sub<Output = Wrapping<T>>, +{ + let _l = lock(dst as usize); + let result = ptr::read(dst); + ptr::write(dst, (Wrapping(result) - Wrapping(val)).0); + result +} + +#[inline] +pub unsafe fn atomic_and<T: Copy + ops::BitAnd<Output = T>>(dst: *mut T, val: T) -> T { + let _l = lock(dst as usize); + let result = ptr::read(dst); + ptr::write(dst, result & val); + result +} + +#[inline] +pub unsafe fn atomic_or<T: Copy + ops::BitOr<Output = T>>(dst: *mut T, val: T) -> T { + let _l = lock(dst as usize); + let result = ptr::read(dst); + ptr::write(dst, result | val); + result +} + +#[inline] +pub unsafe fn atomic_xor<T: Copy + ops::BitXor<Output = T>>(dst: *mut T, val: T) -> T { + let _l = lock(dst as usize); + let result = ptr::read(dst); + ptr::write(dst, result ^ val); + result +} + +#[inline] +pub unsafe fn atomic_min<T: Copy + cmp::Ord>(dst: *mut T, val: T) -> T { + let _l = lock(dst as usize); + let result = ptr::read(dst); + ptr::write(dst, cmp::min(result, val)); + result +} + +#[inline] +pub unsafe fn atomic_max<T: Copy + cmp::Ord>(dst: *mut T, val: T) -> T { + let _l = lock(dst as usize); + let result = ptr::read(dst); + ptr::write(dst, cmp::max(result, val)); + result +} diff --git a/third_party/rust/atomic/src/lib.rs b/third_party/rust/atomic/src/lib.rs new file mode 100644 index 0000000000..d6b19a651b --- /dev/null +++ b/third_party/rust/atomic/src/lib.rs @@ -0,0 +1,735 @@ +// Copyright 2016 Amanieu d'Antras +// +// Licensed under the Apache License, Version 2.0, <LICENSE-APACHE or +// http://apache.org/licenses/LICENSE-2.0> or the MIT license <LICENSE-MIT or +// http://opensource.org/licenses/MIT>, at your option. This file may not be +// copied, modified, or distributed except according to those terms. + +//! Generic `Atomic<T>` wrapper type +//! +//! Atomic types provide primitive shared-memory communication between +//! threads, and are the building blocks of other concurrent types. +//! +//! This library defines a generic atomic wrapper type `Atomic<T>` for all +//! `T: Copy` types. +//! Atomic types present operations that, when used correctly, synchronize +//! updates between threads. +//! +//! Each method takes an `Ordering` which represents the strength of +//! the memory barrier for that operation. These orderings are the +//! same as [LLVM atomic orderings][1]. +//! +//! [1]: http://llvm.org/docs/LangRef.html#memory-model-for-concurrent-operations +//! +//! Atomic variables are safe to share between threads (they implement `Sync`) +//! but they do not themselves provide the mechanism for sharing. The most +//! common way to share an atomic variable is to put it into an `Arc` (an +//! atomically-reference-counted shared pointer). +//! +//! Most atomic types may be stored in static variables, initialized using +//! the `const fn` constructors (only available on nightly). Atomic statics +//! are often used for lazy global initialization. + +#![warn(missing_docs)] +#![no_std] +#![cfg_attr( + feature = "nightly", feature(const_fn, cfg_target_has_atomic, atomic_min_max) +)] + +#[cfg(any(test, feature = "std"))] +#[macro_use] +extern crate std; + +// Re-export some useful definitions from libcore +pub use core::sync::atomic::{fence, Ordering}; + +use core::cell::UnsafeCell; +use core::fmt; + +#[cfg(feature = "std")] +use std::panic::RefUnwindSafe; + +mod fallback; +mod ops; + +/// A generic atomic wrapper type which allows an object to be safely shared +/// between threads. +pub struct Atomic<T: Copy> { + v: UnsafeCell<T>, +} + +// Atomic<T> is only Sync if T is Send +unsafe impl<T: Copy + Send> Sync for Atomic<T> {} + +// Given that atomicity is guaranteed, Atomic<T> is RefUnwindSafe if T is +// +// This is trivially correct for native lock-free atomic types. For those whose +// atomicity is emulated using a spinlock, it is still correct because the +// `Atomic` API does not allow doing any panic-inducing operation after writing +// to the target object. +#[cfg(feature = "std")] +impl<T: Copy + RefUnwindSafe> RefUnwindSafe for Atomic<T> {} + +impl<T: Copy + Default> Default for Atomic<T> { + #[inline] + fn default() -> Self { + Self::new(Default::default()) + } +} + +impl<T: Copy + fmt::Debug> fmt::Debug for Atomic<T> { + fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { + f.debug_tuple("Atomic") + .field(&self.load(Ordering::SeqCst)) + .finish() + } +} + +impl<T: Copy> Atomic<T> { + /// Creates a new `Atomic`. + #[inline] + #[cfg(feature = "nightly")] + pub const fn new(v: T) -> Atomic<T> { + Atomic { + v: UnsafeCell::new(v), + } + } + + /// Creates a new `Atomic`. + #[inline] + #[cfg(not(feature = "nightly"))] + pub fn new(v: T) -> Atomic<T> { + Atomic { + v: UnsafeCell::new(v), + } + } + + /// Checks if `Atomic` objects of this type are lock-free. + /// + /// If an `Atomic` is not lock-free then it may be implemented using locks + /// internally, which makes it unsuitable for some situations (such as + /// communicating with a signal handler). + #[inline] + #[cfg(feature = "nightly")] + pub const fn is_lock_free() -> bool { + ops::atomic_is_lock_free::<T>() + } + + /// Checks if `Atomic` objects of this type are lock-free. + /// + /// If an `Atomic` is not lock-free then it may be implemented using locks + /// internally, which makes it unsuitable for some situations (such as + /// communicating with a signal handler). + #[inline] + #[cfg(not(feature = "nightly"))] + pub fn is_lock_free() -> bool { + ops::atomic_is_lock_free::<T>() + } + + /// Returns a mutable reference to the underlying type. + /// + /// This is safe because the mutable reference guarantees that no other threads are + /// concurrently accessing the atomic data. + #[inline] + pub fn get_mut(&mut self) -> &mut T { + unsafe { &mut *self.v.get() } + } + + /// Consumes the atomic and returns the contained value. + /// + /// This is safe because passing `self` by value guarantees that no other threads are + /// concurrently accessing the atomic data. + #[inline] + pub fn into_inner(self) -> T { + self.v.into_inner() + } + + /// Loads a value from the `Atomic`. + /// + /// `load` takes an `Ordering` argument which describes the memory ordering + /// of this operation. + /// + /// # Panics + /// + /// Panics if `order` is `Release` or `AcqRel`. + #[inline] + pub fn load(&self, order: Ordering) -> T { + unsafe { ops::atomic_load(self.v.get(), order) } + } + + /// Stores a value into the `Atomic`. + /// + /// `store` takes an `Ordering` argument which describes the memory ordering + /// of this operation. + /// + /// # Panics + /// + /// Panics if `order` is `Acquire` or `AcqRel`. + #[inline] + pub fn store(&self, val: T, order: Ordering) { + unsafe { + ops::atomic_store(self.v.get(), val, order); + } + } + + /// Stores a value into the `Atomic`, returning the old value. + /// + /// `swap` takes an `Ordering` argument which describes the memory ordering + /// of this operation. + #[inline] + pub fn swap(&self, val: T, order: Ordering) -> T { + unsafe { ops::atomic_swap(self.v.get(), val, order) } + } + + /// Stores a value into the `Atomic` if the current value is the same as the + /// `current` value. + /// + /// The return value is a result indicating whether the new value was + /// written and containing the previous value. On success this value is + /// guaranteed to be equal to `new`. + /// + /// `compare_exchange` takes two `Ordering` arguments to describe the memory + /// ordering of this operation. The first describes the required ordering if + /// the operation succeeds while the second describes the required ordering + /// when the operation fails. The failure ordering can't be `Acquire` or + /// `AcqRel` and must be equivalent or weaker than the success ordering. + #[inline] + pub fn compare_exchange( + &self, + current: T, + new: T, + success: Ordering, + failure: Ordering, + ) -> Result<T, T> { + unsafe { ops::atomic_compare_exchange(self.v.get(), current, new, success, failure) } + } + + /// Stores a value into the `Atomic` if the current value is the same as the + /// `current` value. + /// + /// Unlike `compare_exchange`, this function is allowed to spuriously fail + /// even when the comparison succeeds, which can result in more efficient + /// code on some platforms. The return value is a result indicating whether + /// the new value was written and containing the previous value. + /// + /// `compare_exchange` takes two `Ordering` arguments to describe the memory + /// ordering of this operation. The first describes the required ordering if + /// the operation succeeds while the second describes the required ordering + /// when the operation fails. The failure ordering can't be `Acquire` or + /// `AcqRel` and must be equivalent or weaker than the success ordering. + /// success ordering. + #[inline] + pub fn compare_exchange_weak( + &self, + current: T, + new: T, + success: Ordering, + failure: Ordering, + ) -> Result<T, T> { + unsafe { ops::atomic_compare_exchange_weak(self.v.get(), current, new, success, failure) } + } +} + +impl Atomic<bool> { + /// Logical "and" with a boolean value. + /// + /// Performs a logical "and" operation on the current value and the argument + /// `val`, and sets the new value to the result. + /// + /// Returns the previous value. + #[inline] + pub fn fetch_and(&self, val: bool, order: Ordering) -> bool { + unsafe { ops::atomic_and(self.v.get(), val, order) } + } + + /// Logical "or" with a boolean value. + /// + /// Performs a logical "or" operation on the current value and the argument + /// `val`, and sets the new value to the result. + /// + /// Returns the previous value. + #[inline] + pub fn fetch_or(&self, val: bool, order: Ordering) -> bool { + unsafe { ops::atomic_or(self.v.get(), val, order) } + } + + /// Logical "xor" with a boolean value. + /// + /// Performs a logical "xor" operation on the current value and the argument + /// `val`, and sets the new value to the result. + /// + /// Returns the previous value. + #[inline] + pub fn fetch_xor(&self, val: bool, order: Ordering) -> bool { + unsafe { ops::atomic_xor(self.v.get(), val, order) } + } +} + +macro_rules! atomic_ops_common { + ($($t:ty)*) => ($( + impl Atomic<$t> { + /// Add to the current value, returning the previous value. + #[inline] + pub fn fetch_add(&self, val: $t, order: Ordering) -> $t { + unsafe { ops::atomic_add(self.v.get(), val, order) } + } + + /// Subtract from the current value, returning the previous value. + #[inline] + pub fn fetch_sub(&self, val: $t, order: Ordering) -> $t { + unsafe { ops::atomic_sub(self.v.get(), val, order) } + } + + /// Bitwise and with the current value, returning the previous value. + #[inline] + pub fn fetch_and(&self, val: $t, order: Ordering) -> $t { + unsafe { ops::atomic_and(self.v.get(), val, order) } + } + + /// Bitwise or with the current value, returning the previous value. + #[inline] + pub fn fetch_or(&self, val: $t, order: Ordering) -> $t { + unsafe { ops::atomic_or(self.v.get(), val, order) } + } + + /// Bitwise xor with the current value, returning the previous value. + #[inline] + pub fn fetch_xor(&self, val: $t, order: Ordering) -> $t { + unsafe { ops::atomic_xor(self.v.get(), val, order) } + } + } + )*); +} +macro_rules! atomic_ops_signed { + ($($t:ty)*) => ( + atomic_ops_common!{ $($t)* } + $( + impl Atomic<$t> { + /// Minimum with the current value. + #[inline] + pub fn fetch_min(&self, val: $t, order: Ordering) -> $t { + unsafe { ops::atomic_min(self.v.get(), val, order) } + } + + /// Maximum with the current value. + #[inline] + pub fn fetch_max(&self, val: $t, order: Ordering) -> $t { + unsafe { ops::atomic_max(self.v.get(), val, order) } + } + } + )* + ); +} +macro_rules! atomic_ops_unsigned { + ($($t:ty)*) => ( + atomic_ops_common!{ $($t)* } + $( + impl Atomic<$t> { + /// Minimum with the current value. + #[inline] + pub fn fetch_min(&self, val: $t, order: Ordering) -> $t { + unsafe { ops::atomic_umin(self.v.get(), val, order) } + } + + /// Maximum with the current value. + #[inline] + pub fn fetch_max(&self, val: $t, order: Ordering) -> $t { + unsafe { ops::atomic_umax(self.v.get(), val, order) } + } + } + )* + ); +} +atomic_ops_signed!{ i8 i16 i32 i64 isize i128 } +atomic_ops_unsigned!{ u8 u16 u32 u64 usize u128 } + +#[cfg(test)] +mod tests { + use core::mem; + use Atomic; + use Ordering::*; + + #[derive(Copy, Clone, Eq, PartialEq, Debug, Default)] + struct Foo(u8, u8); + #[derive(Copy, Clone, Eq, PartialEq, Debug, Default)] + struct Bar(u64, u64); + #[derive(Copy, Clone, Eq, PartialEq, Debug, Default)] + struct Quux(u32); + + #[test] + fn atomic_bool() { + let a = Atomic::new(false); + assert_eq!(Atomic::<bool>::is_lock_free(), cfg!(feature = "nightly")); + assert_eq!(format!("{:?}", a), "Atomic(false)"); + assert_eq!(a.load(SeqCst), false); + a.store(true, SeqCst); + assert_eq!(a.swap(false, SeqCst), true); + assert_eq!(a.compare_exchange(true, false, SeqCst, SeqCst), Err(false)); + assert_eq!(a.compare_exchange(false, true, SeqCst, SeqCst), Ok(false)); + assert_eq!(a.fetch_and(false, SeqCst), true); + assert_eq!(a.fetch_or(true, SeqCst), false); + assert_eq!(a.fetch_xor(false, SeqCst), true); + assert_eq!(a.load(SeqCst), true); + } + + #[test] + fn atomic_i8() { + let a = Atomic::new(0i8); + assert_eq!( + Atomic::<i8>::is_lock_free(), + cfg!(any( + target_pointer_width = "8", + all(feature = "nightly", target_has_atomic = "8") + )) + ); + assert_eq!(format!("{:?}", a), "Atomic(0)"); + assert_eq!(a.load(SeqCst), 0); + a.store(1, SeqCst); + assert_eq!(a.swap(2, SeqCst), 1); + assert_eq!(a.compare_exchange(5, 45, SeqCst, SeqCst), Err(2)); + assert_eq!(a.compare_exchange(2, 3, SeqCst, SeqCst), Ok(2)); + assert_eq!(a.fetch_add(123, SeqCst), 3); + // Make sure overflows are handled correctly + assert_eq!(a.fetch_sub(-56, SeqCst), 126); + assert_eq!(a.fetch_and(7, SeqCst), -74); + assert_eq!(a.fetch_or(64, SeqCst), 6); + assert_eq!(a.fetch_xor(1, SeqCst), 70); + assert_eq!(a.fetch_min(30, SeqCst), 71); + assert_eq!(a.fetch_max(-25, SeqCst), 30); + assert_eq!(a.load(SeqCst), 30); + } + + #[test] + fn atomic_i16() { + let a = Atomic::new(0i16); + assert_eq!( + Atomic::<i16>::is_lock_free(), + cfg!(any( + target_pointer_width = "16", + all(feature = "nightly", target_has_atomic = "16") + )) + ); + assert_eq!(format!("{:?}", a), "Atomic(0)"); + assert_eq!(a.load(SeqCst), 0); + a.store(1, SeqCst); + assert_eq!(a.swap(2, SeqCst), 1); + assert_eq!(a.compare_exchange(5, 45, SeqCst, SeqCst), Err(2)); + assert_eq!(a.compare_exchange(2, 3, SeqCst, SeqCst), Ok(2)); + assert_eq!(a.fetch_add(123, SeqCst), 3); + assert_eq!(a.fetch_sub(-56, SeqCst), 126); + assert_eq!(a.fetch_and(7, SeqCst), 182); + assert_eq!(a.fetch_or(64, SeqCst), 6); + assert_eq!(a.fetch_xor(1, SeqCst), 70); + assert_eq!(a.fetch_min(30, SeqCst), 71); + assert_eq!(a.fetch_max(-25, SeqCst), 30); + assert_eq!(a.load(SeqCst), 30); + } + + #[test] + fn atomic_i32() { + let a = Atomic::new(0i32); + assert_eq!( + Atomic::<i32>::is_lock_free(), + cfg!(any( + target_pointer_width = "32", + all(feature = "nightly", target_has_atomic = "32") + )) + ); + assert_eq!(format!("{:?}", a), "Atomic(0)"); + assert_eq!(a.load(SeqCst), 0); + a.store(1, SeqCst); + assert_eq!(a.swap(2, SeqCst), 1); + assert_eq!(a.compare_exchange(5, 45, SeqCst, SeqCst), Err(2)); + assert_eq!(a.compare_exchange(2, 3, SeqCst, SeqCst), Ok(2)); + assert_eq!(a.fetch_add(123, SeqCst), 3); + assert_eq!(a.fetch_sub(-56, SeqCst), 126); + assert_eq!(a.fetch_and(7, SeqCst), 182); + assert_eq!(a.fetch_or(64, SeqCst), 6); + assert_eq!(a.fetch_xor(1, SeqCst), 70); + assert_eq!(a.fetch_min(30, SeqCst), 71); + assert_eq!(a.fetch_max(-25, SeqCst), 30); + assert_eq!(a.load(SeqCst), 30); + } + + #[test] + fn atomic_i64() { + let a = Atomic::new(0i64); + assert_eq!( + Atomic::<i64>::is_lock_free(), + cfg!(any( + target_pointer_width = "64", + all(feature = "nightly", target_has_atomic = "64") + )) && mem::align_of::<i64>() == 8 + ); + assert_eq!(format!("{:?}", a), "Atomic(0)"); + assert_eq!(a.load(SeqCst), 0); + a.store(1, SeqCst); + assert_eq!(a.swap(2, SeqCst), 1); + assert_eq!(a.compare_exchange(5, 45, SeqCst, SeqCst), Err(2)); + assert_eq!(a.compare_exchange(2, 3, SeqCst, SeqCst), Ok(2)); + assert_eq!(a.fetch_add(123, SeqCst), 3); + assert_eq!(a.fetch_sub(-56, SeqCst), 126); + assert_eq!(a.fetch_and(7, SeqCst), 182); + assert_eq!(a.fetch_or(64, SeqCst), 6); + assert_eq!(a.fetch_xor(1, SeqCst), 70); + assert_eq!(a.fetch_min(30, SeqCst), 71); + assert_eq!(a.fetch_max(-25, SeqCst), 30); + assert_eq!(a.load(SeqCst), 30); + } + + #[test] + fn atomic_i128() { + let a = Atomic::new(0i128); + assert_eq!( + Atomic::<i128>::is_lock_free(), + cfg!(any( + target_pointer_width = "128", + all(feature = "nightly", target_has_atomic = "128") + )) + ); + assert_eq!(format!("{:?}", a), "Atomic(0)"); + assert_eq!(a.load(SeqCst), 0); + a.store(1, SeqCst); + assert_eq!(a.swap(2, SeqCst), 1); + assert_eq!(a.compare_exchange(5, 45, SeqCst, SeqCst), Err(2)); + assert_eq!(a.compare_exchange(2, 3, SeqCst, SeqCst), Ok(2)); + assert_eq!(a.fetch_add(123, SeqCst), 3); + assert_eq!(a.fetch_sub(-56, SeqCst), 126); + assert_eq!(a.fetch_and(7, SeqCst), 182); + assert_eq!(a.fetch_or(64, SeqCst), 6); + assert_eq!(a.fetch_xor(1, SeqCst), 70); + assert_eq!(a.fetch_min(30, SeqCst), 71); + assert_eq!(a.fetch_max(-25, SeqCst), 30); + assert_eq!(a.load(SeqCst), 30); + } + + #[test] + fn atomic_isize() { + let a = Atomic::new(0isize); + assert!(Atomic::<isize>::is_lock_free()); + assert_eq!(format!("{:?}", a), "Atomic(0)"); + assert_eq!(a.load(SeqCst), 0); + a.store(1, SeqCst); + assert_eq!(a.swap(2, SeqCst), 1); + assert_eq!(a.compare_exchange(5, 45, SeqCst, SeqCst), Err(2)); + assert_eq!(a.compare_exchange(2, 3, SeqCst, SeqCst), Ok(2)); + assert_eq!(a.fetch_add(123, SeqCst), 3); + assert_eq!(a.fetch_sub(-56, SeqCst), 126); + assert_eq!(a.fetch_and(7, SeqCst), 182); + assert_eq!(a.fetch_or(64, SeqCst), 6); + assert_eq!(a.fetch_xor(1, SeqCst), 70); + assert_eq!(a.fetch_min(30, SeqCst), 71); + assert_eq!(a.fetch_max(-25, SeqCst), 30); + assert_eq!(a.load(SeqCst), 30); + } + + #[test] + fn atomic_u8() { + let a = Atomic::new(0u8); + assert_eq!( + Atomic::<u8>::is_lock_free(), + cfg!(any( + target_pointer_width = "8", + all(feature = "nightly", target_has_atomic = "8") + )) + ); + assert_eq!(format!("{:?}", a), "Atomic(0)"); + assert_eq!(a.load(SeqCst), 0); + a.store(1, SeqCst); + assert_eq!(a.swap(2, SeqCst), 1); + assert_eq!(a.compare_exchange(5, 45, SeqCst, SeqCst), Err(2)); + assert_eq!(a.compare_exchange(2, 3, SeqCst, SeqCst), Ok(2)); + assert_eq!(a.fetch_add(123, SeqCst), 3); + assert_eq!(a.fetch_sub(56, SeqCst), 126); + assert_eq!(a.fetch_and(7, SeqCst), 70); + assert_eq!(a.fetch_or(64, SeqCst), 6); + assert_eq!(a.fetch_xor(1, SeqCst), 70); + assert_eq!(a.fetch_min(30, SeqCst), 71); + assert_eq!(a.fetch_max(25, SeqCst), 30); + assert_eq!(a.load(SeqCst), 30); + } + + #[test] + fn atomic_u16() { + let a = Atomic::new(0u16); + assert_eq!( + Atomic::<u16>::is_lock_free(), + cfg!(any( + target_pointer_width = "16", + all(feature = "nightly", target_has_atomic = "16") + )) + ); + assert_eq!(format!("{:?}", a), "Atomic(0)"); + assert_eq!(a.load(SeqCst), 0); + a.store(1, SeqCst); + assert_eq!(a.swap(2, SeqCst), 1); + assert_eq!(a.compare_exchange(5, 45, SeqCst, SeqCst), Err(2)); + assert_eq!(a.compare_exchange(2, 3, SeqCst, SeqCst), Ok(2)); + assert_eq!(a.fetch_add(123, SeqCst), 3); + assert_eq!(a.fetch_sub(56, SeqCst), 126); + assert_eq!(a.fetch_and(7, SeqCst), 70); + assert_eq!(a.fetch_or(64, SeqCst), 6); + assert_eq!(a.fetch_xor(1, SeqCst), 70); + assert_eq!(a.fetch_min(30, SeqCst), 71); + assert_eq!(a.fetch_max(25, SeqCst), 30); + assert_eq!(a.load(SeqCst), 30); + } + + #[test] + fn atomic_u32() { + let a = Atomic::new(0u32); + assert_eq!( + Atomic::<u32>::is_lock_free(), + cfg!(any( + target_pointer_width = "32", + all(feature = "nightly", target_has_atomic = "32") + )) + ); + assert_eq!(format!("{:?}", a), "Atomic(0)"); + assert_eq!(a.load(SeqCst), 0); + a.store(1, SeqCst); + assert_eq!(a.swap(2, SeqCst), 1); + assert_eq!(a.compare_exchange(5, 45, SeqCst, SeqCst), Err(2)); + assert_eq!(a.compare_exchange(2, 3, SeqCst, SeqCst), Ok(2)); + assert_eq!(a.fetch_add(123, SeqCst), 3); + assert_eq!(a.fetch_sub(56, SeqCst), 126); + assert_eq!(a.fetch_and(7, SeqCst), 70); + assert_eq!(a.fetch_or(64, SeqCst), 6); + assert_eq!(a.fetch_xor(1, SeqCst), 70); + assert_eq!(a.fetch_min(30, SeqCst), 71); + assert_eq!(a.fetch_max(25, SeqCst), 30); + assert_eq!(a.load(SeqCst), 30); + } + + #[test] + fn atomic_u64() { + let a = Atomic::new(0u64); + assert_eq!( + Atomic::<u64>::is_lock_free(), + cfg!(any( + target_pointer_width = "64", + all(feature = "nightly", target_has_atomic = "64") + )) && mem::align_of::<u64>() == 8 + ); + assert_eq!(format!("{:?}", a), "Atomic(0)"); + assert_eq!(a.load(SeqCst), 0); + a.store(1, SeqCst); + assert_eq!(a.swap(2, SeqCst), 1); + assert_eq!(a.compare_exchange(5, 45, SeqCst, SeqCst), Err(2)); + assert_eq!(a.compare_exchange(2, 3, SeqCst, SeqCst), Ok(2)); + assert_eq!(a.fetch_add(123, SeqCst), 3); + assert_eq!(a.fetch_sub(56, SeqCst), 126); + assert_eq!(a.fetch_and(7, SeqCst), 70); + assert_eq!(a.fetch_or(64, SeqCst), 6); + assert_eq!(a.fetch_xor(1, SeqCst), 70); + assert_eq!(a.fetch_min(30, SeqCst), 71); + assert_eq!(a.fetch_max(25, SeqCst), 30); + assert_eq!(a.load(SeqCst), 30); + } + + #[test] + fn atomic_u128() { + let a = Atomic::new(0u128); + assert_eq!( + Atomic::<u128>::is_lock_free(), + cfg!(any( + target_pointer_width = "128", + all(feature = "nightly", target_has_atomic = "128") + )) + ); + assert_eq!(format!("{:?}", a), "Atomic(0)"); + assert_eq!(a.load(SeqCst), 0); + a.store(1, SeqCst); + assert_eq!(a.swap(2, SeqCst), 1); + assert_eq!(a.compare_exchange(5, 45, SeqCst, SeqCst), Err(2)); + assert_eq!(a.compare_exchange(2, 3, SeqCst, SeqCst), Ok(2)); + assert_eq!(a.fetch_add(123, SeqCst), 3); + assert_eq!(a.fetch_sub(56, SeqCst), 126); + assert_eq!(a.fetch_and(7, SeqCst), 70); + assert_eq!(a.fetch_or(64, SeqCst), 6); + assert_eq!(a.fetch_xor(1, SeqCst), 70); + assert_eq!(a.fetch_min(30, SeqCst), 71); + assert_eq!(a.fetch_max(25, SeqCst), 30); + assert_eq!(a.load(SeqCst), 30); + } + + #[test] + fn atomic_usize() { + let a = Atomic::new(0usize); + assert!(Atomic::<usize>::is_lock_free()); + assert_eq!(format!("{:?}", a), "Atomic(0)"); + assert_eq!(a.load(SeqCst), 0); + a.store(1, SeqCst); + assert_eq!(a.swap(2, SeqCst), 1); + assert_eq!(a.compare_exchange(5, 45, SeqCst, SeqCst), Err(2)); + assert_eq!(a.compare_exchange(2, 3, SeqCst, SeqCst), Ok(2)); + assert_eq!(a.fetch_add(123, SeqCst), 3); + assert_eq!(a.fetch_sub(56, SeqCst), 126); + assert_eq!(a.fetch_and(7, SeqCst), 70); + assert_eq!(a.fetch_or(64, SeqCst), 6); + assert_eq!(a.fetch_xor(1, SeqCst), 70); + assert_eq!(a.fetch_min(30, SeqCst), 71); + assert_eq!(a.fetch_max(25, SeqCst), 30); + assert_eq!(a.load(SeqCst), 30); + } + + #[test] + fn atomic_foo() { + let a = Atomic::default(); + assert_eq!(Atomic::<Foo>::is_lock_free(), false); + assert_eq!(format!("{:?}", a), "Atomic(Foo(0, 0))"); + assert_eq!(a.load(SeqCst), Foo(0, 0)); + a.store(Foo(1, 1), SeqCst); + assert_eq!(a.swap(Foo(2, 2), SeqCst), Foo(1, 1)); + assert_eq!( + a.compare_exchange(Foo(5, 5), Foo(45, 45), SeqCst, SeqCst), + Err(Foo(2, 2)) + ); + assert_eq!( + a.compare_exchange(Foo(2, 2), Foo(3, 3), SeqCst, SeqCst), + Ok(Foo(2, 2)) + ); + assert_eq!(a.load(SeqCst), Foo(3, 3)); + } + + #[test] + fn atomic_bar() { + let a = Atomic::default(); + assert_eq!(Atomic::<Bar>::is_lock_free(), false); + assert_eq!(format!("{:?}", a), "Atomic(Bar(0, 0))"); + assert_eq!(a.load(SeqCst), Bar(0, 0)); + a.store(Bar(1, 1), SeqCst); + assert_eq!(a.swap(Bar(2, 2), SeqCst), Bar(1, 1)); + assert_eq!( + a.compare_exchange(Bar(5, 5), Bar(45, 45), SeqCst, SeqCst), + Err(Bar(2, 2)) + ); + assert_eq!( + a.compare_exchange(Bar(2, 2), Bar(3, 3), SeqCst, SeqCst), + Ok(Bar(2, 2)) + ); + assert_eq!(a.load(SeqCst), Bar(3, 3)); + } + + #[test] + fn atomic_quxx() { + let a = Atomic::default(); + assert_eq!( + Atomic::<Quux>::is_lock_free(), + cfg!(any(feature = "nightly", target_pointer_width = "32")) + ); + assert_eq!(format!("{:?}", a), "Atomic(Quux(0))"); + assert_eq!(a.load(SeqCst), Quux(0)); + a.store(Quux(1), SeqCst); + assert_eq!(a.swap(Quux(2), SeqCst), Quux(1)); + assert_eq!( + a.compare_exchange(Quux(5), Quux(45), SeqCst, SeqCst), + Err(Quux(2)) + ); + assert_eq!( + a.compare_exchange(Quux(2), Quux(3), SeqCst, SeqCst), + Ok(Quux(2)) + ); + assert_eq!(a.load(SeqCst), Quux(3)); + } +} diff --git a/third_party/rust/atomic/src/ops.rs b/third_party/rust/atomic/src/ops.rs new file mode 100644 index 0000000000..3626c9ed9a --- /dev/null +++ b/third_party/rust/atomic/src/ops.rs @@ -0,0 +1,666 @@ +// Copyright 2016 Amanieu d'Antras +// +// Licensed under the Apache License, Version 2.0, <LICENSE-APACHE or +// http://apache.org/licenses/LICENSE-2.0> or the MIT license <LICENSE-MIT or +// http://opensource.org/licenses/MIT>, at your option. This file may not be +// copied, modified, or distributed except according to those terms. + +use core::cmp; +use core::mem; +use core::num::Wrapping; +use core::ops; +use core::sync::atomic::Ordering; +use fallback; + +#[cfg(all(feature = "nightly", target_has_atomic = "8"))] +use core::sync::atomic::{ AtomicI8, AtomicU8 }; +#[cfg(all(feature = "nightly", target_has_atomic = "16"))] +use core::sync::atomic::{ AtomicI16, AtomicU16 }; +#[cfg(all(feature = "nightly", target_has_atomic = "32"))] +use core::sync::atomic::{ AtomicI32, AtomicU32 }; +#[cfg(all(feature = "nightly", target_has_atomic = "64"))] +use core::sync::atomic::{ AtomicI64, AtomicU64 }; + +#[cfg(not(feature = "nightly"))] +use core::sync::atomic::AtomicUsize; +#[cfg(not(feature = "nightly"))] +const SIZEOF_USIZE: usize = mem::size_of::<usize>(); +#[cfg(not(feature = "nightly"))] +const ALIGNOF_USIZE: usize = mem::align_of::<usize>(); + +#[cfg(feature = "nightly")] +#[inline] +pub const fn atomic_is_lock_free<T>() -> bool { + let size = mem::size_of::<T>(); + // FIXME: switch to … && … && … once that operator is supported in const functions + (1 == size.count_ones()) & (8 >= size) & (mem::align_of::<T>() >= size) +} + +#[cfg(not(feature = "nightly"))] +#[inline] +pub fn atomic_is_lock_free<T>() -> bool { + let size = mem::size_of::<T>(); + 1 == size.count_ones() && SIZEOF_USIZE >= size && mem::align_of::<T>() >= ALIGNOF_USIZE +} + +#[inline] +pub unsafe fn atomic_load<T>(dst: *mut T, order: Ordering) -> T { + match mem::size_of::<T>() { + #[cfg(all(feature = "nightly", target_has_atomic = "8"))] + 1 if mem::align_of::<T>() >= 1 => + { + mem::transmute_copy(&(*(dst as *const AtomicU8)).load(order)) + } + #[cfg(all(feature = "nightly", target_has_atomic = "16"))] + 2 if mem::align_of::<T>() >= 2 => + { + mem::transmute_copy(&(*(dst as *const AtomicU16)).load(order)) + } + #[cfg(all(feature = "nightly", target_has_atomic = "32"))] + 4 if mem::align_of::<T>() >= 4 => + { + mem::transmute_copy(&(*(dst as *const AtomicU32)).load(order)) + } + #[cfg(all(feature = "nightly", target_has_atomic = "64"))] + 8 if mem::align_of::<T>() >= 8 => + { + mem::transmute_copy(&(*(dst as *const AtomicU64)).load(order)) + } + #[cfg(not(feature = "nightly"))] + SIZEOF_USIZE if mem::align_of::<T>() >= ALIGNOF_USIZE => + { + mem::transmute_copy(&(*(dst as *const AtomicUsize)).load(order)) + } + _ => fallback::atomic_load(dst), + } +} + +#[inline] +pub unsafe fn atomic_store<T>(dst: *mut T, val: T, order: Ordering) { + match mem::size_of::<T>() { + #[cfg(all(feature = "nightly", target_has_atomic = "8"))] + 1 if mem::align_of::<T>() >= 1 => + { + (*(dst as *const AtomicU8)).store(mem::transmute_copy(&val), order) + } + #[cfg(all(feature = "nightly", target_has_atomic = "16"))] + 2 if mem::align_of::<T>() >= 2 => + { + (*(dst as *const AtomicU16)).store(mem::transmute_copy(&val), order) + } + #[cfg(all(feature = "nightly", target_has_atomic = "32"))] + 4 if mem::align_of::<T>() >= 4 => + { + (*(dst as *const AtomicU32)).store(mem::transmute_copy(&val), order) + } + #[cfg(all(feature = "nightly", target_has_atomic = "64"))] + 8 if mem::align_of::<T>() >= 8 => + { + (*(dst as *const AtomicU64)).store(mem::transmute_copy(&val), order) + } + #[cfg(not(feature = "nightly"))] + SIZEOF_USIZE if mem::align_of::<T>() >= ALIGNOF_USIZE => + { + (*(dst as *const AtomicUsize)).store(mem::transmute_copy(&val), order) + } + _ => fallback::atomic_store(dst, val), + } +} + +#[inline] +pub unsafe fn atomic_swap<T>(dst: *mut T, val: T, order: Ordering) -> T { + match mem::size_of::<T>() { + #[cfg(all(feature = "nightly", target_has_atomic = "8"))] + 1 if mem::align_of::<T>() >= 1 => + { + mem::transmute_copy(&(*(dst as *const AtomicU8)).swap(mem::transmute_copy(&val), order)) + } + #[cfg(all(feature = "nightly", target_has_atomic = "16"))] + 2 if mem::align_of::<T>() >= 2 => + { + mem::transmute_copy( + &(*(dst as *const AtomicU16)).swap(mem::transmute_copy(&val), order), + ) + } + #[cfg(all(feature = "nightly", target_has_atomic = "32"))] + 4 if mem::align_of::<T>() >= 4 => + { + mem::transmute_copy( + &(*(dst as *const AtomicU32)).swap(mem::transmute_copy(&val), order), + ) + } + #[cfg(all(feature = "nightly", target_has_atomic = "64"))] + 8 if mem::align_of::<T>() >= 8 => + { + mem::transmute_copy( + &(*(dst as *const AtomicU64)).swap(mem::transmute_copy(&val), order), + ) + } + #[cfg(not(feature = "nightly"))] + SIZEOF_USIZE if mem::align_of::<T>() >= ALIGNOF_USIZE => + { + mem::transmute_copy( + &(*(dst as *const AtomicUsize)).swap(mem::transmute_copy(&val), order), + ) + } + _ => fallback::atomic_swap(dst, val), + } +} + +#[inline] +unsafe fn map_result<T, U>(r: Result<T, T>) -> Result<U, U> { + match r { + Ok(x) => Ok(mem::transmute_copy(&x)), + Err(x) => Err(mem::transmute_copy(&x)), + } +} + +#[inline] +pub unsafe fn atomic_compare_exchange<T>( + dst: *mut T, + current: T, + new: T, + success: Ordering, + failure: Ordering, +) -> Result<T, T> { + match mem::size_of::<T>() { + #[cfg(all(feature = "nightly", target_has_atomic = "8"))] + 1 if mem::align_of::<T>() >= 1 => + { + map_result((*(dst as *const AtomicU8)).compare_exchange( + mem::transmute_copy(¤t), + mem::transmute_copy(&new), + success, + failure, + )) + } + #[cfg(all(feature = "nightly", target_has_atomic = "16"))] + 2 if mem::align_of::<T>() >= 2 => + { + map_result((*(dst as *const AtomicU16)).compare_exchange( + mem::transmute_copy(¤t), + mem::transmute_copy(&new), + success, + failure, + )) + } + #[cfg(all(feature = "nightly", target_has_atomic = "32"))] + 4 if mem::align_of::<T>() >= 4 => + { + map_result((*(dst as *const AtomicU32)).compare_exchange( + mem::transmute_copy(¤t), + mem::transmute_copy(&new), + success, + failure, + )) + } + #[cfg(all(feature = "nightly", target_has_atomic = "64"))] + 8 if mem::align_of::<T>() >= 8 => + { + map_result((*(dst as *const AtomicU64)).compare_exchange( + mem::transmute_copy(¤t), + mem::transmute_copy(&new), + success, + failure, + )) + } + #[cfg(not(feature = "nightly"))] + SIZEOF_USIZE if mem::align_of::<T>() >= ALIGNOF_USIZE => + { + map_result((*(dst as *const AtomicUsize)).compare_exchange( + mem::transmute_copy(¤t), + mem::transmute_copy(&new), + success, + failure, + )) + } + _ => fallback::atomic_compare_exchange(dst, current, new), + } +} + +#[inline] +pub unsafe fn atomic_compare_exchange_weak<T>( + dst: *mut T, + current: T, + new: T, + success: Ordering, + failure: Ordering, +) -> Result<T, T> { + match mem::size_of::<T>() { + #[cfg(all(feature = "nightly", target_has_atomic = "8"))] + 1 if mem::align_of::<T>() >= 1 => + { + map_result((*(dst as *const AtomicU8)).compare_exchange_weak( + mem::transmute_copy(¤t), + mem::transmute_copy(&new), + success, + failure, + )) + } + #[cfg(all(feature = "nightly", target_has_atomic = "16"))] + 2 if mem::align_of::<T>() >= 2 => + { + map_result((*(dst as *const AtomicU16)).compare_exchange_weak( + mem::transmute_copy(¤t), + mem::transmute_copy(&new), + success, + failure, + )) + } + #[cfg(all(feature = "nightly", target_has_atomic = "32"))] + 4 if mem::align_of::<T>() >= 4 => + { + map_result((*(dst as *const AtomicU32)).compare_exchange_weak( + mem::transmute_copy(¤t), + mem::transmute_copy(&new), + success, + failure, + )) + } + #[cfg(all(feature = "nightly", target_has_atomic = "64"))] + 8 if mem::align_of::<T>() >= 8 => + { + map_result((*(dst as *const AtomicU64)).compare_exchange_weak( + mem::transmute_copy(¤t), + mem::transmute_copy(&new), + success, + failure, + )) + } + #[cfg(not(feature = "nightly"))] + SIZEOF_USIZE if mem::align_of::<T>() >= ALIGNOF_USIZE => + { + map_result((*(dst as *const AtomicUsize)).compare_exchange_weak( + mem::transmute_copy(¤t), + mem::transmute_copy(&new), + success, + failure, + )) + } + _ => fallback::atomic_compare_exchange(dst, current, new), + } +} + +#[inline] +pub unsafe fn atomic_add<T: Copy>(dst: *mut T, val: T, order: Ordering) -> T +where + Wrapping<T>: ops::Add<Output = Wrapping<T>>, +{ + match mem::size_of::<T>() { + #[cfg(all(feature = "nightly", target_has_atomic = "8"))] + 1 if mem::align_of::<T>() >= 1 => + { + mem::transmute_copy( + &(*(dst as *const AtomicU8)).fetch_add(mem::transmute_copy(&val), order), + ) + } + #[cfg(all(feature = "nightly", target_has_atomic = "16"))] + 2 if mem::align_of::<T>() >= 2 => + { + mem::transmute_copy( + &(*(dst as *const AtomicU16)).fetch_add(mem::transmute_copy(&val), order), + ) + } + #[cfg(all(feature = "nightly", target_has_atomic = "32"))] + 4 if mem::align_of::<T>() >= 4 => + { + mem::transmute_copy( + &(*(dst as *const AtomicU32)).fetch_add(mem::transmute_copy(&val), order), + ) + } + #[cfg(all(feature = "nightly", target_has_atomic = "64"))] + 8 if mem::align_of::<T>() >= 8 => + { + mem::transmute_copy( + &(*(dst as *const AtomicU64)).fetch_add(mem::transmute_copy(&val), order), + ) + } + #[cfg(not(feature = "nightly"))] + SIZEOF_USIZE if mem::align_of::<T>() >= ALIGNOF_USIZE => + { + mem::transmute_copy( + &(*(dst as *const AtomicUsize)).fetch_add(mem::transmute_copy(&val), order), + ) + } + _ => fallback::atomic_add(dst, val), + } +} + +#[inline] +pub unsafe fn atomic_sub<T: Copy>(dst: *mut T, val: T, order: Ordering) -> T +where + Wrapping<T>: ops::Sub<Output = Wrapping<T>>, +{ + match mem::size_of::<T>() { + #[cfg(all(feature = "nightly", target_has_atomic = "8"))] + 1 if mem::align_of::<T>() >= 1 => + { + mem::transmute_copy( + &(*(dst as *const AtomicU8)).fetch_sub(mem::transmute_copy(&val), order), + ) + } + #[cfg(all(feature = "nightly", target_has_atomic = "16"))] + 2 if mem::align_of::<T>() >= 2 => + { + mem::transmute_copy( + &(*(dst as *const AtomicU16)).fetch_sub(mem::transmute_copy(&val), order), + ) + } + #[cfg(all(feature = "nightly", target_has_atomic = "32"))] + 4 if mem::align_of::<T>() >= 4 => + { + mem::transmute_copy( + &(*(dst as *const AtomicU32)).fetch_sub(mem::transmute_copy(&val), order), + ) + } + #[cfg(all(feature = "nightly", target_has_atomic = "64"))] + 8 if mem::align_of::<T>() >= 8 => + { + mem::transmute_copy( + &(*(dst as *const AtomicU64)).fetch_sub(mem::transmute_copy(&val), order), + ) + } + #[cfg(not(feature = "nightly"))] + SIZEOF_USIZE if mem::align_of::<T>() >= ALIGNOF_USIZE => + { + mem::transmute_copy( + &(*(dst as *const AtomicUsize)).fetch_sub(mem::transmute_copy(&val), order), + ) + } + _ => fallback::atomic_sub(dst, val), + } +} + +#[inline] +pub unsafe fn atomic_and<T: Copy + ops::BitAnd<Output = T>>( + dst: *mut T, + val: T, + order: Ordering, +) -> T { + match mem::size_of::<T>() { + #[cfg(all(feature = "nightly", target_has_atomic = "8"))] + 1 if mem::align_of::<T>() >= 1 => + { + mem::transmute_copy( + &(*(dst as *const AtomicU8)).fetch_and(mem::transmute_copy(&val), order), + ) + } + #[cfg(all(feature = "nightly", target_has_atomic = "16"))] + 2 if mem::align_of::<T>() >= 2 => + { + mem::transmute_copy( + &(*(dst as *const AtomicU16)).fetch_and(mem::transmute_copy(&val), order), + ) + } + #[cfg(all(feature = "nightly", target_has_atomic = "32"))] + 4 if mem::align_of::<T>() >= 4 => + { + mem::transmute_copy( + &(*(dst as *const AtomicU32)).fetch_and(mem::transmute_copy(&val), order), + ) + } + #[cfg(all(feature = "nightly", target_has_atomic = "64"))] + 8 if mem::align_of::<T>() >= 8 => + { + mem::transmute_copy( + &(*(dst as *const AtomicU64)).fetch_and(mem::transmute_copy(&val), order), + ) + } + #[cfg(not(feature = "nightly"))] + SIZEOF_USIZE if mem::align_of::<T>() >= ALIGNOF_USIZE => + { + mem::transmute_copy( + &(*(dst as *const AtomicUsize)).fetch_and(mem::transmute_copy(&val), order), + ) + } + _ => fallback::atomic_and(dst, val), + } +} + +#[inline] +pub unsafe fn atomic_or<T: Copy + ops::BitOr<Output = T>>( + dst: *mut T, + val: T, + order: Ordering, +) -> T { + match mem::size_of::<T>() { + #[cfg(all(feature = "nightly", target_has_atomic = "8"))] + 1 if mem::align_of::<T>() >= 1 => + { + mem::transmute_copy( + &(*(dst as *const AtomicU8)).fetch_or(mem::transmute_copy(&val), order), + ) + } + #[cfg(all(feature = "nightly", target_has_atomic = "16"))] + 2 if mem::align_of::<T>() >= 2 => + { + mem::transmute_copy( + &(*(dst as *const AtomicU16)).fetch_or(mem::transmute_copy(&val), order), + ) + } + #[cfg(all(feature = "nightly", target_has_atomic = "32"))] + 4 if mem::align_of::<T>() >= 4 => + { + mem::transmute_copy( + &(*(dst as *const AtomicU32)).fetch_or(mem::transmute_copy(&val), order), + ) + } + #[cfg(all(feature = "nightly", target_has_atomic = "64"))] + 8 if mem::align_of::<T>() >= 8 => + { + mem::transmute_copy( + &(*(dst as *const AtomicU64)).fetch_or(mem::transmute_copy(&val), order), + ) + } + #[cfg(not(feature = "nightly"))] + SIZEOF_USIZE if mem::align_of::<T>() >= ALIGNOF_USIZE => + { + mem::transmute_copy( + &(*(dst as *const AtomicUsize)).fetch_or(mem::transmute_copy(&val), order), + ) + } + _ => fallback::atomic_or(dst, val), + } +} + +#[inline] +pub unsafe fn atomic_xor<T: Copy + ops::BitXor<Output = T>>( + dst: *mut T, + val: T, + order: Ordering, +) -> T { + match mem::size_of::<T>() { + #[cfg(all(feature = "nightly", target_has_atomic = "8"))] + 1 if mem::align_of::<T>() >= 1 => + { + mem::transmute_copy( + &(*(dst as *const AtomicU8)).fetch_xor(mem::transmute_copy(&val), order), + ) + } + #[cfg(all(feature = "nightly", target_has_atomic = "16"))] + 2 if mem::align_of::<T>() >= 2 => + { + mem::transmute_copy( + &(*(dst as *const AtomicU16)).fetch_xor(mem::transmute_copy(&val), order), + ) + } + #[cfg(all(feature = "nightly", target_has_atomic = "32"))] + 4 if mem::align_of::<T>() >= 4 => + { + mem::transmute_copy( + &(*(dst as *const AtomicU32)).fetch_xor(mem::transmute_copy(&val), order), + ) + } + #[cfg(all(feature = "nightly", target_has_atomic = "64"))] + 8 if mem::align_of::<T>() >= 8 => + { + mem::transmute_copy( + &(*(dst as *const AtomicU64)).fetch_xor(mem::transmute_copy(&val), order), + ) + } + #[cfg(not(feature = "nightly"))] + SIZEOF_USIZE if mem::align_of::<T>() >= ALIGNOF_USIZE => + { + mem::transmute_copy( + &(*(dst as *const AtomicUsize)).fetch_xor(mem::transmute_copy(&val), order), + ) + } + _ => fallback::atomic_xor(dst, val), + } +} + +#[inline] +pub unsafe fn atomic_min<T: Copy + cmp::Ord>(dst: *mut T, val: T, order: Ordering) -> T { + // Silence warning, fetch_min is not stable yet + #[cfg(not(feature = "nightly"))] + let _ = order; + + match mem::size_of::<T>() { + #[cfg(all(feature = "nightly", target_has_atomic = "8"))] + 1 if mem::align_of::<T>() >= 1 => + { + mem::transmute_copy( + &(*(dst as *const AtomicI8)).fetch_min(mem::transmute_copy(&val), order), + ) + } + #[cfg(all(feature = "nightly", target_has_atomic = "16"))] + 2 if mem::align_of::<T>() >= 2 => + { + mem::transmute_copy( + &(*(dst as *const AtomicI16)).fetch_min(mem::transmute_copy(&val), order), + ) + } + #[cfg(all(feature = "nightly", target_has_atomic = "32"))] + 4 if mem::align_of::<T>() >= 4 => + { + mem::transmute_copy( + &(*(dst as *const AtomicI32)).fetch_min(mem::transmute_copy(&val), order), + ) + } + #[cfg(all(feature = "nightly", target_has_atomic = "64"))] + 8 if mem::align_of::<T>() >= 8 => + { + mem::transmute_copy( + &(*(dst as *const AtomicI64)).fetch_min(mem::transmute_copy(&val), order), + ) + } + _ => fallback::atomic_min(dst, val), + } +} + +#[inline] +pub unsafe fn atomic_max<T: Copy + cmp::Ord>(dst: *mut T, val: T, order: Ordering) -> T { + // Silence warning, fetch_min is not stable yet + #[cfg(not(feature = "nightly"))] + let _ = order; + + match mem::size_of::<T>() { + #[cfg(all(feature = "nightly", target_has_atomic = "8"))] + 1 if mem::align_of::<T>() >= 1 => + { + mem::transmute_copy( + &(*(dst as *const AtomicI8)).fetch_max(mem::transmute_copy(&val), order), + ) + } + #[cfg(all(feature = "nightly", target_has_atomic = "16"))] + 2 if mem::align_of::<T>() >= 2 => + { + mem::transmute_copy( + &(*(dst as *const AtomicI16)).fetch_max(mem::transmute_copy(&val), order), + ) + } + #[cfg(all(feature = "nightly", target_has_atomic = "32"))] + 4 if mem::align_of::<T>() >= 4 => + { + mem::transmute_copy( + &(*(dst as *const AtomicI32)).fetch_max(mem::transmute_copy(&val), order), + ) + } + #[cfg(all(feature = "nightly", target_has_atomic = "64"))] + 8 if mem::align_of::<T>() >= 8 => + { + mem::transmute_copy( + &(*(dst as *const AtomicI64)).fetch_max(mem::transmute_copy(&val), order), + ) + } + _ => fallback::atomic_max(dst, val), + } +} + +#[inline] +pub unsafe fn atomic_umin<T: Copy + cmp::Ord>(dst: *mut T, val: T, order: Ordering) -> T { + // Silence warning, fetch_min is not stable yet + #[cfg(not(feature = "nightly"))] + let _ = order; + + match mem::size_of::<T>() { + #[cfg(all(feature = "nightly", target_has_atomic = "8"))] + 1 if mem::align_of::<T>() >= 1 => + { + mem::transmute_copy( + &(*(dst as *const AtomicU8)).fetch_min(mem::transmute_copy(&val), order), + ) + } + #[cfg(all(feature = "nightly", target_has_atomic = "16"))] + 2 if mem::align_of::<T>() >= 2 => + { + mem::transmute_copy( + &(*(dst as *const AtomicU16)).fetch_min(mem::transmute_copy(&val), order), + ) + } + #[cfg(all(feature = "nightly", target_has_atomic = "32"))] + 4 if mem::align_of::<T>() >= 4 => + { + mem::transmute_copy( + &(*(dst as *const AtomicU32)).fetch_min(mem::transmute_copy(&val), order), + ) + } + #[cfg(all(feature = "nightly", target_has_atomic = "64"))] + 8 if mem::align_of::<T>() >= 8 => + { + mem::transmute_copy( + &(*(dst as *const AtomicU64)).fetch_min(mem::transmute_copy(&val), order), + ) + } + _ => fallback::atomic_min(dst, val), + } +} + +#[inline] +pub unsafe fn atomic_umax<T: Copy + cmp::Ord>(dst: *mut T, val: T, order: Ordering) -> T { + // Silence warning, fetch_min is not stable yet + #[cfg(not(feature = "nightly"))] + let _ = order; + + match mem::size_of::<T>() { + #[cfg(all(feature = "nightly", target_has_atomic = "8"))] + 1 if mem::align_of::<T>() >= 1 => + { + mem::transmute_copy( + &(*(dst as *const AtomicU8)).fetch_max(mem::transmute_copy(&val), order), + ) + } + #[cfg(all(feature = "nightly", target_has_atomic = "16"))] + 2 if mem::align_of::<T>() >= 2 => + { + mem::transmute_copy( + &(*(dst as *const AtomicU16)).fetch_max(mem::transmute_copy(&val), order), + ) + } + #[cfg(all(feature = "nightly", target_has_atomic = "32"))] + 4 if mem::align_of::<T>() >= 4 => + { + mem::transmute_copy( + &(*(dst as *const AtomicU32)).fetch_max(mem::transmute_copy(&val), order), + ) + } + #[cfg(all(feature = "nightly", target_has_atomic = "64"))] + 8 if mem::align_of::<T>() >= 8 => + { + mem::transmute_copy( + &(*(dst as *const AtomicU64)).fetch_max(mem::transmute_copy(&val), order), + ) + } + _ => fallback::atomic_max(dst, val), + } +} diff --git a/third_party/rust/atomic_refcell/.cargo-checksum.json b/third_party/rust/atomic_refcell/.cargo-checksum.json new file mode 100644 index 0000000000..0dc5177384 --- /dev/null +++ b/third_party/rust/atomic_refcell/.cargo-checksum.json @@ -0,0 +1 @@ +{"files":{"Cargo.toml":"1191be2168fb6a9914afd20cd5a1c7ac5e612596b834a60ac495b45629805a51","README.md":"6b468f17809063c5dcee5758d1daca147d74e2297a9dc78a5e50ae13d9ea6e42","benches/basic.rs":"aba00ab044b37a7fb4e5c855cf88a323a04d6143b651717e227fdd12735602f3","src/lib.rs":"631e765b36b20ab47c7cd35fb0bf2e9b6f9c2bf2a0ab72bd67d59759ff53a71f","tests/basic.rs":"2cefa20188254d8357a595975733ad1bffb4de90933d5d9e9caa17232c1d646b"},"package":"73b5e5f48b927f04e952dedc932f31995a65a0bf65ec971c74436e51bf6e970d"}
\ No newline at end of file diff --git a/third_party/rust/atomic_refcell/Cargo.toml b/third_party/rust/atomic_refcell/Cargo.toml new file mode 100644 index 0000000000..d71703f230 --- /dev/null +++ b/third_party/rust/atomic_refcell/Cargo.toml @@ -0,0 +1,21 @@ +# THIS FILE IS AUTOMATICALLY GENERATED BY CARGO +# +# When uploading crates to the registry Cargo will automatically +# "normalize" Cargo.toml files for maximal compatibility +# with all versions of Cargo and also rewrite `path` dependencies +# to registry (e.g., crates.io) dependencies. +# +# If you are reading this file be aware that the original Cargo.toml +# will likely look very different (and much more reasonable). +# See Cargo.toml.orig for the original contents. + +[package] +name = "atomic_refcell" +version = "0.1.8" +authors = ["Bobby Holley <bobbyholley@gmail.com>"] +description = "Threadsafe RefCell" +documentation = "https://docs.rs/atomic_refcell/" +license = "Apache-2.0/MIT" +repository = "https://github.com/bholley/atomic_refcell" + +[dependencies] diff --git a/third_party/rust/atomic_refcell/README.md b/third_party/rust/atomic_refcell/README.md new file mode 100644 index 0000000000..de72c55daa --- /dev/null +++ b/third_party/rust/atomic_refcell/README.md @@ -0,0 +1,2 @@ +# atomic_refcell +Threadsafe RefCell for Rust. diff --git a/third_party/rust/atomic_refcell/benches/basic.rs b/third_party/rust/atomic_refcell/benches/basic.rs new file mode 100644 index 0000000000..3902a98a37 --- /dev/null +++ b/third_party/rust/atomic_refcell/benches/basic.rs @@ -0,0 +1,37 @@ +#![feature(test)] + +extern crate atomic_refcell; +extern crate test; + +use atomic_refcell::AtomicRefCell; +use test::Bencher; + +#[derive(Default)] +struct Bar(u32); + +#[bench] +fn immutable_borrow(b: &mut Bencher) { + let a = AtomicRefCell::new(Bar::default()); + b.iter(|| a.borrow()); +} + +#[bench] +fn immutable_second_borrow(b: &mut Bencher) { + let a = AtomicRefCell::new(Bar::default()); + let _first = a.borrow(); + b.iter(|| a.borrow()); +} + +#[bench] +fn immutable_third_borrow(b: &mut Bencher) { + let a = AtomicRefCell::new(Bar::default()); + let _first = a.borrow(); + let _second = a.borrow(); + b.iter(|| a.borrow()); +} + +#[bench] +fn mutable_borrow(b: &mut Bencher) { + let a = AtomicRefCell::new(Bar::default()); + b.iter(|| a.borrow_mut()); +} diff --git a/third_party/rust/atomic_refcell/src/lib.rs b/third_party/rust/atomic_refcell/src/lib.rs new file mode 100644 index 0000000000..dbf599aa52 --- /dev/null +++ b/third_party/rust/atomic_refcell/src/lib.rs @@ -0,0 +1,486 @@ +/* This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ + +//! Implements a container type providing RefCell-like semantics for objects +//! shared across threads. +//! +//! RwLock is traditionally considered to be the |Sync| analogue of RefCell. +//! However, for consumers that can guarantee that they will never mutably +//! borrow the contents concurrently with immutable borrows, an RwLock is +//! overkill, and has key disadvantages: +//! * Performance: Even the fastest existing implementation of RwLock (that of +//! parking_lot) performs at least two atomic operations during immutable +//! borrows. This makes mutable borrows significantly cheaper than immutable +//! borrows, leading to weird incentives when writing performance-critical +//! code. +//! * Features: Implementing AtomicRefCell on top of RwLock makes it impossible +//! to implement useful things like AtomicRef{,Mut}::map. +//! +//! As such, we re-implement RefCell semantics from scratch with a single atomic +//! reference count. The primary complication of this scheme relates to keeping +//! things in a consistent state when one thread performs an illegal borrow and +//! panics. Since an AtomicRefCell can be accessed by multiple threads, and since +//! panics are recoverable, we need to ensure that an illegal (panicking) access by +//! one thread does not lead to undefined behavior on other, still-running threads. +//! +//! So we represent things as follows: +//! * Any value with the high bit set (so half the total refcount space) indicates +//! a mutable borrow. +//! * Mutable borrows perform an atomic compare-and-swap, swapping in the high bit +//! if the current value is zero. If the current value is non-zero, the thread +//! panics and the value is left undisturbed. +//! * Immutable borrows perform an atomic increment. If the new value has the high +//! bit set, the thread panics. The incremented refcount is left as-is, since it +//! still represents a valid mutable borrow. When the mutable borrow is released, +//! the refcount is set unconditionally to zero, clearing any stray increments by +//! panicked threads. +//! +//! There are a few additional purely-academic complications to handle overflow, +//! which are documented in the implementation. +//! +//! The rest of this module is mostly derived by copy-pasting the implementation of +//! RefCell and fixing things up as appropriate. Certain non-threadsafe methods +//! have been removed. We segment the concurrency logic from the rest of the code to +//! keep the tricky parts small and easy to audit. + +#![no_std] +#![allow(unsafe_code)] +#![deny(missing_docs)] + +use core::cell::UnsafeCell; +use core::cmp; +use core::fmt; +use core::fmt::{Debug, Display}; +use core::ops::{Deref, DerefMut}; +use core::sync::atomic; +use core::sync::atomic::AtomicUsize; + +/// A threadsafe analogue to RefCell. +pub struct AtomicRefCell<T: ?Sized> { + borrow: AtomicUsize, + value: UnsafeCell<T>, +} + +/// An error returned by [`AtomicRefCell::try_borrow`](struct.AtomicRefCell.html#method.try_borrow). +pub struct BorrowError { + _private: (), +} + +impl Debug for BorrowError { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_struct("BorrowError").finish() + } +} + +impl Display for BorrowError { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + Display::fmt("already mutably borrowed", f) + } +} + +/// An error returned by [`AtomicRefCell::try_borrow_mut`](struct.AtomicRefCell.html#method.try_borrow_mut). +pub struct BorrowMutError { + _private: (), +} + +impl Debug for BorrowMutError { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_struct("BorrowMutError").finish() + } +} + +impl Display for BorrowMutError { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + Display::fmt("already borrowed", f) + } +} + +impl<T> AtomicRefCell<T> { + /// Creates a new `AtomicRefCell` containing `value`. + #[inline] + pub const fn new(value: T) -> AtomicRefCell<T> { + AtomicRefCell { + borrow: AtomicUsize::new(0), + value: UnsafeCell::new(value), + } + } + + /// Consumes the `AtomicRefCell`, returning the wrapped value. + #[inline] + pub fn into_inner(self) -> T { + debug_assert!(self.borrow.load(atomic::Ordering::Acquire) == 0); + self.value.into_inner() + } +} + +impl<T: ?Sized> AtomicRefCell<T> { + /// Immutably borrows the wrapped value. + #[inline] + pub fn borrow(&self) -> AtomicRef<T> { + match AtomicBorrowRef::try_new(&self.borrow) { + Ok(borrow) => AtomicRef { + value: unsafe { &*self.value.get() }, + borrow, + }, + Err(s) => panic!("{}", s), + } + } + + /// Attempts to immutably borrow the wrapped value, but instead of panicking + /// on a failed borrow, returns `Err`. + #[inline] + pub fn try_borrow(&self) -> Result<AtomicRef<T>, BorrowError> { + match AtomicBorrowRef::try_new(&self.borrow) { + Ok(borrow) => Ok(AtomicRef { + value: unsafe { &*self.value.get() }, + borrow, + }), + Err(_) => Err(BorrowError { _private: () }), + } + } + + /// Mutably borrows the wrapped value. + #[inline] + pub fn borrow_mut(&self) -> AtomicRefMut<T> { + match AtomicBorrowRefMut::try_new(&self.borrow) { + Ok(borrow) => AtomicRefMut { + value: unsafe { &mut *self.value.get() }, + borrow, + }, + Err(s) => panic!("{}", s), + } + } + + /// Attempts to mutably borrow the wrapped value, but instead of panicking + /// on a failed borrow, returns `Err`. + #[inline] + pub fn try_borrow_mut(&self) -> Result<AtomicRefMut<T>, BorrowMutError> { + match AtomicBorrowRefMut::try_new(&self.borrow) { + Ok(borrow) => Ok(AtomicRefMut { + value: unsafe { &mut *self.value.get() }, + borrow, + }), + Err(_) => Err(BorrowMutError { _private: () }), + } + } + + /// Returns a raw pointer to the underlying data in this cell. + /// + /// External synchronization is needed to avoid data races when dereferencing + /// the pointer. + #[inline] + pub fn as_ptr(&self) -> *mut T { + self.value.get() + } + + /// Returns a mutable reference to the wrapped value. + /// + /// No runtime checks take place (unless debug assertions are enabled) + /// because this call borrows `AtomicRefCell` mutably at compile-time. + #[inline] + pub fn get_mut(&mut self) -> &mut T { + debug_assert!(self.borrow.load(atomic::Ordering::Acquire) == 0); + unsafe { &mut *self.value.get() } + } +} + +// +// Core synchronization logic. Keep this section small and easy to audit. +// + +const HIGH_BIT: usize = !(::core::usize::MAX >> 1); +const MAX_FAILED_BORROWS: usize = HIGH_BIT + (HIGH_BIT >> 1); + +struct AtomicBorrowRef<'b> { + borrow: &'b AtomicUsize, +} + +impl<'b> AtomicBorrowRef<'b> { + #[inline] + fn try_new(borrow: &'b AtomicUsize) -> Result<Self, &'static str> { + let new = borrow.fetch_add(1, atomic::Ordering::Acquire) + 1; + if new & HIGH_BIT != 0 { + // If the new count has the high bit set, that almost certainly + // means there's an pre-existing mutable borrow. In that case, + // we simply leave the increment as a benign side-effect and + // return `Err`. Once the mutable borrow is released, the + // count will be reset to zero unconditionally. + // + // The overflow check here ensures that an unbounded number of + // immutable borrows during the scope of one mutable borrow + // will soundly trigger a panic (or abort) rather than UB. + Self::check_overflow(borrow, new); + Err("already mutably borrowed") + } else { + Ok(AtomicBorrowRef { borrow: borrow }) + } + } + + #[cold] + #[inline(never)] + fn check_overflow(borrow: &'b AtomicUsize, new: usize) { + if new == HIGH_BIT { + // We overflowed into the reserved upper half of the refcount + // space. Before panicking, decrement the refcount to leave things + // in a consistent immutable-borrow state. + // + // This can basically only happen if somebody forget()s AtomicRefs + // in a tight loop. + borrow.fetch_sub(1, atomic::Ordering::Release); + panic!("too many immutable borrows"); + } else if new >= MAX_FAILED_BORROWS { + // During the mutable borrow, an absurd number of threads have + // attempted to increment the refcount with immutable borrows. + // To avoid hypothetically wrapping the refcount, we abort the + // process once a certain threshold is reached. + // + // This requires billions of borrows to fail during the scope of + // one mutable borrow, and so is very unlikely to happen in a real + // program. + // + // To avoid a potential unsound state after overflowing, we make + // sure the entire process aborts. + // + // Right now, there's no stable way to do that without `std`: + // https://github.com/rust-lang/rust/issues/67952 + // As a workaround, we cause an abort by making this thread panic + // during the unwinding of another panic. + // + // On platforms where the panic strategy is already 'abort', the + // ForceAbort object here has no effect, as the program already + // panics before it is dropped. + struct ForceAbort; + impl Drop for ForceAbort { + fn drop(&mut self) { + panic!("Aborting to avoid unsound state of AtomicRefCell"); + } + } + let _abort = ForceAbort; + panic!("Too many failed borrows"); + } + } +} + +impl<'b> Drop for AtomicBorrowRef<'b> { + #[inline] + fn drop(&mut self) { + let old = self.borrow.fetch_sub(1, atomic::Ordering::Release); + // This assertion is technically incorrect in the case where another + // thread hits the hypothetical overflow case, since we might observe + // the refcount before it fixes it up (and panics). But that never will + // never happen in a real program, and this is a debug_assert! anyway. + debug_assert!(old & HIGH_BIT == 0); + } +} + +struct AtomicBorrowRefMut<'b> { + borrow: &'b AtomicUsize, +} + +impl<'b> Drop for AtomicBorrowRefMut<'b> { + #[inline] + fn drop(&mut self) { + self.borrow.store(0, atomic::Ordering::Release); + } +} + +impl<'b> AtomicBorrowRefMut<'b> { + #[inline] + fn try_new(borrow: &'b AtomicUsize) -> Result<AtomicBorrowRefMut<'b>, &'static str> { + // Use compare-and-swap to avoid corrupting the immutable borrow count + // on illegal mutable borrows. + let old = match borrow.compare_exchange( + 0, + HIGH_BIT, + atomic::Ordering::Acquire, + atomic::Ordering::Relaxed, + ) { + Ok(x) => x, + Err(x) => x, + }; + + if old == 0 { + Ok(AtomicBorrowRefMut { borrow }) + } else if old & HIGH_BIT == 0 { + Err("already immutably borrowed") + } else { + Err("already mutably borrowed") + } + } +} + +unsafe impl<T: ?Sized + Send> Send for AtomicRefCell<T> {} +unsafe impl<T: ?Sized + Send + Sync> Sync for AtomicRefCell<T> {} + +// +// End of core synchronization logic. No tricky thread stuff allowed below +// this point. +// + +impl<T: Clone> Clone for AtomicRefCell<T> { + #[inline] + fn clone(&self) -> AtomicRefCell<T> { + AtomicRefCell::new(self.borrow().clone()) + } +} + +impl<T: Default> Default for AtomicRefCell<T> { + #[inline] + fn default() -> AtomicRefCell<T> { + AtomicRefCell::new(Default::default()) + } +} + +impl<T: ?Sized + PartialEq> PartialEq for AtomicRefCell<T> { + #[inline] + fn eq(&self, other: &AtomicRefCell<T>) -> bool { + *self.borrow() == *other.borrow() + } +} + +impl<T: ?Sized + Eq> Eq for AtomicRefCell<T> {} + +impl<T: ?Sized + PartialOrd> PartialOrd for AtomicRefCell<T> { + #[inline] + fn partial_cmp(&self, other: &AtomicRefCell<T>) -> Option<cmp::Ordering> { + self.borrow().partial_cmp(&*other.borrow()) + } +} + +impl<T: ?Sized + Ord> Ord for AtomicRefCell<T> { + #[inline] + fn cmp(&self, other: &AtomicRefCell<T>) -> cmp::Ordering { + self.borrow().cmp(&*other.borrow()) + } +} + +impl<T> From<T> for AtomicRefCell<T> { + fn from(t: T) -> AtomicRefCell<T> { + AtomicRefCell::new(t) + } +} + +impl<'b> Clone for AtomicBorrowRef<'b> { + #[inline] + fn clone(&self) -> AtomicBorrowRef<'b> { + AtomicBorrowRef::try_new(self.borrow).unwrap() + } +} + +/// A wrapper type for an immutably borrowed value from an `AtomicRefCell<T>`. +pub struct AtomicRef<'b, T: ?Sized + 'b> { + value: &'b T, + borrow: AtomicBorrowRef<'b>, +} + +impl<'b, T: ?Sized> Deref for AtomicRef<'b, T> { + type Target = T; + + #[inline] + fn deref(&self) -> &T { + self.value + } +} + +impl<'b, T: ?Sized> AtomicRef<'b, T> { + /// Copies an `AtomicRef`. + #[inline] + pub fn clone(orig: &AtomicRef<'b, T>) -> AtomicRef<'b, T> { + AtomicRef { + value: orig.value, + borrow: orig.borrow.clone(), + } + } + + /// Make a new `AtomicRef` for a component of the borrowed data. + #[inline] + pub fn map<U: ?Sized, F>(orig: AtomicRef<'b, T>, f: F) -> AtomicRef<'b, U> + where + F: FnOnce(&T) -> &U, + { + AtomicRef { + value: f(orig.value), + borrow: orig.borrow, + } + } + + /// Make a new `AtomicRef` for an optional component of the borrowed data. + #[inline] + pub fn filter_map<U: ?Sized, F>(orig: AtomicRef<'b, T>, f: F) -> Option<AtomicRef<'b, U>> + where + F: FnOnce(&T) -> Option<&U>, + { + Some(AtomicRef { + value: f(orig.value)?, + borrow: orig.borrow, + }) + } +} + +impl<'b, T: ?Sized> AtomicRefMut<'b, T> { + /// Make a new `AtomicRefMut` for a component of the borrowed data, e.g. an enum + /// variant. + #[inline] + pub fn map<U: ?Sized, F>(orig: AtomicRefMut<'b, T>, f: F) -> AtomicRefMut<'b, U> + where + F: FnOnce(&mut T) -> &mut U, + { + AtomicRefMut { + value: f(orig.value), + borrow: orig.borrow, + } + } + + /// Make a new `AtomicRefMut` for an optional component of the borrowed data. + #[inline] + pub fn filter_map<U: ?Sized, F>(orig: AtomicRefMut<'b, T>, f: F) -> Option<AtomicRefMut<'b, U>> + where + F: FnOnce(&mut T) -> Option<&mut U>, + { + Some(AtomicRefMut { + value: f(orig.value)?, + borrow: orig.borrow, + }) + } +} + +/// A wrapper type for a mutably borrowed value from an `AtomicRefCell<T>`. +pub struct AtomicRefMut<'b, T: ?Sized + 'b> { + value: &'b mut T, + borrow: AtomicBorrowRefMut<'b>, +} + +impl<'b, T: ?Sized> Deref for AtomicRefMut<'b, T> { + type Target = T; + + #[inline] + fn deref(&self) -> &T { + self.value + } +} + +impl<'b, T: ?Sized> DerefMut for AtomicRefMut<'b, T> { + #[inline] + fn deref_mut(&mut self) -> &mut T { + self.value + } +} + +impl<'b, T: ?Sized + Debug + 'b> Debug for AtomicRef<'b, T> { + fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { + self.value.fmt(f) + } +} + +impl<'b, T: ?Sized + Debug + 'b> Debug for AtomicRefMut<'b, T> { + fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { + self.value.fmt(f) + } +} + +impl<T: ?Sized + Debug> Debug for AtomicRefCell<T> { + fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { + write!(f, "AtomicRefCell {{ ... }}") + } +} diff --git a/third_party/rust/atomic_refcell/tests/basic.rs b/third_party/rust/atomic_refcell/tests/basic.rs new file mode 100644 index 0000000000..a37833085d --- /dev/null +++ b/third_party/rust/atomic_refcell/tests/basic.rs @@ -0,0 +1,156 @@ +extern crate atomic_refcell; + +use atomic_refcell::{AtomicRef, AtomicRefCell, AtomicRefMut}; + +#[derive(Debug)] +struct Foo { + u: u32, +} + +#[derive(Debug)] +struct Bar { + f: Foo, +} + +impl Default for Bar { + fn default() -> Self { + Bar { f: Foo { u: 42 } } + } +} + +// FIXME(bholley): Add tests to exercise this in concurrent scenarios. + +#[test] +fn immutable() { + let a = AtomicRefCell::new(Bar::default()); + let _first = a.borrow(); + let _second = a.borrow(); +} + +#[test] +fn try_immutable() { + let a = AtomicRefCell::new(Bar::default()); + let _first = a.try_borrow().unwrap(); + let _second = a.try_borrow().unwrap(); +} + +#[test] +fn mutable() { + let a = AtomicRefCell::new(Bar::default()); + let _ = a.borrow_mut(); +} + +#[test] +fn try_mutable() { + let a = AtomicRefCell::new(Bar::default()); + let _ = a.try_borrow_mut().unwrap(); +} + +#[test] +fn get_mut() { + let mut a = AtomicRefCell::new(Bar::default()); + let _ = a.get_mut(); +} + +#[test] +fn interleaved() { + let a = AtomicRefCell::new(Bar::default()); + { + let _ = a.borrow_mut(); + } + { + let _first = a.borrow(); + let _second = a.borrow(); + } + { + let _ = a.borrow_mut(); + } +} + +#[test] +fn try_interleaved() { + let a = AtomicRefCell::new(Bar::default()); + { + let _ = a.try_borrow_mut().unwrap(); + } + { + let _first = a.try_borrow().unwrap(); + let _second = a.try_borrow().unwrap(); + let _ = a.try_borrow_mut().unwrap_err(); + } + { + let _first = a.try_borrow_mut().unwrap(); + let _ = a.try_borrow().unwrap_err(); + } +} + +#[test] +#[should_panic(expected = "already immutably borrowed")] +fn immutable_then_mutable() { + let a = AtomicRefCell::new(Bar::default()); + let _first = a.borrow(); + let _second = a.borrow_mut(); +} + +#[test] +fn immutable_then_try_mutable() { + let a = AtomicRefCell::new(Bar::default()); + let _first = a.borrow(); + let _second = a.try_borrow_mut().unwrap_err(); +} + +#[test] +#[should_panic(expected = "already mutably borrowed")] +fn mutable_then_immutable() { + let a = AtomicRefCell::new(Bar::default()); + let _first = a.borrow_mut(); + let _second = a.borrow(); +} + +#[test] +fn mutable_then_try_immutable() { + let a = AtomicRefCell::new(Bar::default()); + let _first = a.borrow_mut(); + let _second = a.try_borrow().unwrap_err(); +} + +#[test] +#[should_panic(expected = "already mutably borrowed")] +fn double_mutable() { + let a = AtomicRefCell::new(Bar::default()); + let _first = a.borrow_mut(); + let _second = a.borrow_mut(); +} + +#[test] +fn mutable_then_try_mutable() { + let a = AtomicRefCell::new(Bar::default()); + let _first = a.borrow_mut(); + let _second = a.try_borrow_mut().unwrap_err(); +} + +#[test] +fn map() { + let a = AtomicRefCell::new(Bar::default()); + let b = a.borrow(); + assert_eq!(b.f.u, 42); + let c = AtomicRef::map(b, |x| &x.f); + assert_eq!(c.u, 42); + let d = AtomicRef::map(c, |x| &x.u); + assert_eq!(*d, 42); +} + +#[test] +fn map_mut() { + let a = AtomicRefCell::new(Bar::default()); + let mut b = a.borrow_mut(); + assert_eq!(b.f.u, 42); + b.f.u = 43; + let mut c = AtomicRefMut::map(b, |x| &mut x.f); + assert_eq!(c.u, 43); + c.u = 44; + let mut d = AtomicRefMut::map(c, |x| &mut x.u); + assert_eq!(*d, 44); + *d = 45; + assert_eq!(*d, 45); +} |