diff options
| -rw-r--r-- | Cargo.toml | 10 | ||||
| -rw-r--r-- | LICENSE | 121 | ||||
| -rw-r--r-- | README.md | 22 | ||||
| -rw-r--r-- | src/collection.rs | 129 | ||||
| -rw-r--r-- | src/key.rs | 11 | ||||
| -rw-r--r-- | src/lib.rs | 9 | ||||
| -rw-r--r-- | src/lockable.rs | 79 | ||||
| -rw-r--r-- | src/mutex.rs | 29 | ||||
| -rw-r--r-- | src/rwlock.rs | 79 |
9 files changed, 416 insertions, 73 deletions
@@ -1,9 +1,15 @@ [package] name = "happylock" version = "0.1.0" +authors = ["Mica White <botahamec@outlook.com>"] edition = "2021" -description = "Locks without Deadlocks" -license = "Unlicense" +description = "Free deadlock prevention" +documentation = "https://docs.rs/happylock" +readme = "README.md" +repository = "https://github.com/botahamec/happylock/" +license = "CC0-1.0" +keywords = ["deadlock", "mutex", "rwlock"] +categories = ["concurrency"] # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html @@ -0,0 +1,121 @@ +Creative Commons Legal Code + +CC0 1.0 Universal + + CREATIVE COMMONS CORPORATION IS NOT A LAW FIRM AND DOES NOT PROVIDE + LEGAL SERVICES. DISTRIBUTION OF THIS DOCUMENT DOES NOT CREATE AN + ATTORNEY-CLIENT RELATIONSHIP. CREATIVE COMMONS PROVIDES THIS + INFORMATION ON AN "AS-IS" BASIS. CREATIVE COMMONS MAKES NO WARRANTIES + REGARDING THE USE OF THIS DOCUMENT OR THE INFORMATION OR WORKS + PROVIDED HEREUNDER, AND DISCLAIMS LIABILITY FOR DAMAGES RESULTING FROM + THE USE OF THIS DOCUMENT OR THE INFORMATION OR WORKS PROVIDED + HEREUNDER. + +Statement of Purpose + +The laws of most jurisdictions throughout the world automatically confer +exclusive Copyright and Related Rights (defined below) upon the creator +and subsequent owner(s) (each and all, an "owner") of an original work of +authorship and/or a database (each, a "Work"). + +Certain owners wish to permanently relinquish those rights to a Work for +the purpose of contributing to a commons of creative, cultural and +scientific works ("Commons") that the public can reliably and without fear +of later claims of infringement build upon, modify, incorporate in other +works, reuse and redistribute as freely as possible in any form whatsoever +and for any purposes, including without limitation commercial purposes. +These owners may contribute to the Commons to promote the ideal of a free +culture and the further production of creative, cultural and scientific +works, or to gain reputation or greater distribution for their Work in +part through the use and efforts of others. + +For these and/or other purposes and motivations, and without any +expectation of additional consideration or compensation, the person +associating CC0 with a Work (the "Affirmer"), to the extent that he or she +is an owner of Copyright and Related Rights in the Work, voluntarily +elects to apply CC0 to the Work and publicly distribute the Work under its +terms, with knowledge of his or her Copyright and Related Rights in the +Work and the meaning and intended legal effect of CC0 on those rights. + +1. Copyright and Related Rights. A Work made available under CC0 may be +protected by copyright and related or neighboring rights ("Copyright and +Related Rights"). Copyright and Related Rights include, but are not +limited to, the following: + + i. the right to reproduce, adapt, distribute, perform, display, + communicate, and translate a Work; + ii. moral rights retained by the original author(s) and/or performer(s); +iii. publicity and privacy rights pertaining to a person's image or + likeness depicted in a Work; + iv. rights protecting against unfair competition in regards to a Work, + subject to the limitations in paragraph 4(a), below; + v. rights protecting the extraction, dissemination, use and reuse of data + in a Work; + vi. database rights (such as those arising under Directive 96/9/EC of the + European Parliament and of the Council of 11 March 1996 on the legal + protection of databases, and under any national implementation + thereof, including any amended or successor version of such + directive); and +vii. other similar, equivalent or corresponding rights throughout the + world based on applicable law or treaty, and any national + implementations thereof. + +2. Waiver. To the greatest extent permitted by, but not in contravention +of, applicable law, Affirmer hereby overtly, fully, permanently, +irrevocably and unconditionally waives, abandons, and surrenders all of +Affirmer's Copyright and Related Rights and associated claims and causes +of action, whether now known or unknown (including existing as well as +future claims and causes of action), in the Work (i) in all territories +worldwide, (ii) for the maximum duration provided by applicable law or +treaty (including future time extensions), (iii) in any current or future +medium and for any number of copies, and (iv) for any purpose whatsoever, +including without limitation commercial, advertising or promotional +purposes (the "Waiver"). Affirmer makes the Waiver for the benefit of each +member of the public at large and to the detriment of Affirmer's heirs and +successors, fully intending that such Waiver shall not be subject to +revocation, rescission, cancellation, termination, or any other legal or +equitable action to disrupt the quiet enjoyment of the Work by the public +as contemplated by Affirmer's express Statement of Purpose. + +3. Public License Fallback. Should any part of the Waiver for any reason +be judged legally invalid or ineffective under applicable law, then the +Waiver shall be preserved to the maximum extent permitted taking into +account Affirmer's express Statement of Purpose. In addition, to the +extent the Waiver is so judged Affirmer hereby grants to each affected +person a royalty-free, non transferable, non sublicensable, non exclusive, +irrevocable and unconditional license to exercise Affirmer's Copyright and +Related Rights in the Work (i) in all territories worldwide, (ii) for the +maximum duration provided by applicable law or treaty (including future +time extensions), (iii) in any current or future medium and for any number +of copies, and (iv) for any purpose whatsoever, including without +limitation commercial, advertising or promotional purposes (the +"License"). The License shall be deemed effective as of the date CC0 was +applied by Affirmer to the Work. Should any part of the License for any +reason be judged legally invalid or ineffective under applicable law, such +partial invalidity or ineffectiveness shall not invalidate the remainder +of the License, and in such case Affirmer hereby affirms that he or she +will not (i) exercise any of his or her remaining Copyright and Related +Rights in the Work or (ii) assert any associated claims and causes of +action with respect to the Work, in either case contrary to Affirmer's +express Statement of Purpose. + +4. Limitations and Disclaimers. + + a. No trademark or patent rights held by Affirmer are waived, abandoned, + surrendered, licensed or otherwise affected by this document. + b. Affirmer offers the Work as-is and makes no representations or + warranties of any kind concerning the Work, express, implied, + statutory or otherwise, including without limitation warranties of + title, merchantability, fitness for a particular purpose, non + infringement, or the absence of latent or other defects, accuracy, or + the present or absence of errors, whether or not discoverable, all to + the greatest extent permissible under applicable law. + c. Affirmer disclaims responsibility for clearing rights of other persons + that may apply to the Work or any use thereof, including without + limitation any person's Copyright and Related Rights in the Work. + Further, Affirmer disclaims responsibility for obtaining any necessary + consents, permissions or other rights required for any use of the + Work. + d. Affirmer understands and acknowledges that Creative Commons is not a + party to this document and has no duty or obligation with respect to + this CC0 or use of the Work. @@ -52,7 +52,7 @@ for _ in 0..N { let key = ThreadKey::lock().unwrap(); // happylock ensures at runtime there are no duplicate locks - let collection = LockCollection::new((&DATA_1, &DATA_2)); + let collection = LockCollection::try_new((&DATA_1, &DATA_2)).unwrap(); let mut guard = collection.lock(key); *guard.1 = (100 - *guard.0).to_string(); @@ -77,20 +77,22 @@ println!("{}", *data.1); ## Future Work -Are the ergonomics here any good? This is completely untreaded territory. Maybe there are some useful helper methods we don't have here yet. Maybe `try_lock` should return a `Result`. Maybe `lock_api` or `spin` implements some useful methods that I kept out for this proof of concept. +Although this library is able to successfully prevent deadlocks, livelocks may still be an issue. Imagine thread 1 gets resource 1, thread 2 gets resource 2, thread 1 realizes it can't get resource 2, thread 2 realizes it can't get resource 1, thread 1 drops resource 1, thread 2 drops resource 2, and then repeat forever. In practice, this situation probably wouldn't last forever. But it would be nice if this could be prevented somehow. A more fair system for getting sets of locks would help, but I have no clue what that looks like. -There might be some promise in trying to prevent circular wait. There could be a special type that only allows the locking mutexes in a specific order. This would still require a thread key so that nobody tries to unlock multiple lock sequences at the same time. But this could improve performance, since we wouldn't need to worry about making sure the lock operations are atomic. The biggest problem is that `LockSequence::lock_next` would need to return the same value each time, which is not very ergonomic. +We should add `Condvar` at some point. I didn't because I've never used it before, and I'm probably not the right person to solve this problem. I think all the synchronization problems could be solved by having `Condvar::wait` take a `ThreadKey` instead of a `MutexGuard`. Something similar can probably be done for `Barrier`. But again, I'm no expert. -Although this library is able to successfully prevent deadlocks, livelocks may still be an issue. Imagine thread 1 gets resource 1, thread 2 gets resource 2, thread 1 realizes it can't get resource 2, thread 2 realizes it can't get resource 1, thread 1 drops resource 1, thread 2 drops resource 2, and then repeat forever. In practice, this situation probably wouldn't last forever. But it would be nice if this could be prevented somehow. +Do `OnceLock` or `LazyLock` ever deadlock? We might not need to add those here. -I want to try to get this working without the standard library. There are a few problems with this though. For instance, this crate uses `thread_local` to allow other threads to have their own keys. Also, the only practical type of mutex that would work is a spinlock. Although, more could be implemented using the `RawMutex` trait. The `LockCollection` requires memory allocation at this time in order to check for duplicate locks. +It'd be nice to be able to use the mutexes built into the operating system, saving on binary size. Using `std::sync::Mutex` sounds promising, but it doesn't implement `RawMutex`, and implementing that is very difficult, if not impossible. -More types might be lockable using a `LockGuard`. In addition, some sort of `DynamicLock` type might be useful so that, for example, a `Mutex<usize>` and an `RwLock<usize>` could be unlocked at the same time inside of a `Vec<DynamicLock<usize>>`. Although, this wouldn't solve the problem of needing a `Mutex<usize>` and a `Mutex<String>` at the same time. This would be better solved usin the existing tuple system. +Personally, I don't like mutex poisoning, but maybe it can be worked into the library if you're into that sort of thing. -It'd be nice to be able to use the mutexes built into the operating system. Using `std::sync::Mutex` sounds promising, but it doesn't implement `RawMutex`, and implementing that is very difficult, if not impossible. +Are the ergonomics here any good? This is completely uncharted territory. Maybe there are some useful helper methods we don't have here yet. Maybe `try_lock` should return a `Result`. Maybe `lock_api` or `spin` implements some useful methods that I kept out for this proof of concept. Maybe there are some lock-specific methods that could be added to `LockCollection`. More types might be lockable using a `LockGuard`. -A more fair system for getting sets of locks would help, but I have no clue what that looks like. +I want to try to get this working without the standard library. There are a few problems with this though. For instance, this crate uses `thread_local` to allow other threads to have their own keys. Also, the only practical type of mutex that would work is a spinlock. Although, more could be implemented using the `RawMutex` trait. The `LockCollection` requires memory allocation at this time in order to check for duplicate locks. -Maybe adding other primitives such as condvars and barriers? +It'd be interesting to add some methods such as `lock_clone` or `lock_swap`. This would still require a thread key, in case the mutex is already locked. The only way this could be done without a thread key is with a `&mut Mutex<T>`, but we already have `get_mut`. A special lock that looks like `Cell` but implements `Sync` could be shared without a thread key, because the lock would be dropped immediately (solving non-preemptive allocation). It might make some common operations easier. -Personally, I don't like mutex poisoning, but maybe it can be worked into the library if you're into that sort of thing. +There might be some use in trying to prevent circular wait. There could be a special type that only allows the locking mutexes in a specific order. This would still require a thread key so that nobody tries to unlock multiple lock sequences at the same time. The biggest problem is that `LockSequence::lock_next` would need to return the same value each time, which is not very flexible. Most use cases for this are solved already by using `LockCollection<OwnedLockable>`. + +Some sort of `DynamicLock` type might be useful so that, for example, a `Mutex<usize>` and an `RwLock<usize>` could be unlocked at the same time inside of a `Vec<DynamicLock<usize>>`. Although, this wouldn't solve the problem of needing a `Mutex<usize>` and a `Mutex<String>` at the same time. This would be better solved usin the existing tuple system. diff --git a/src/collection.rs b/src/collection.rs index 34de620..1ee5956 100644 --- a/src/collection.rs +++ b/src/collection.rs @@ -1,7 +1,5 @@ -use std::{ - marker::PhantomData, - ops::{Deref, DerefMut}, -}; +use std::marker::PhantomData; +use std::ops::{Deref, DerefMut}; use crate::{ key::Keyable, @@ -9,6 +7,7 @@ use crate::{ }; /// returns `true` if the list contains a duplicate +#[must_use] fn contains_duplicates(l: &[usize]) -> bool { for i in 0..l.len() { for j in (i + 1)..l.len() { @@ -26,6 +25,7 @@ fn contains_duplicates(l: &[usize]) -> bool { /// This could be a tuple of [`Lockable`] types, an array, or a `Vec`. But it /// can be safely locked without causing a deadlock. To do this, it is very /// important that no duplicate locks are included within. +#[derive(Debug, Clone, Copy)] pub struct LockCollection<L> { collection: L, } @@ -37,15 +37,81 @@ pub struct LockGuard<'a, 'key: 'a, L: Lockable<'a>, Key: Keyable + 'key> { _phantom: PhantomData<&'key ()>, } -impl<L> LockCollection<L> { - /// Creates a new collections of locks. - /// - /// # Safety - /// - /// This results in undefined behavior if any locks are presented twice - /// within this collection. - pub const unsafe fn new_unchecked(collection: L) -> Self { - Self { collection } +impl<'a, L: OwnedLockable<'a>> From<L> for LockCollection<L> { + fn from(value: L) -> Self { + Self::new(value) + } +} + +impl<'a, L: OwnedLockable<'a>> AsRef<L> for LockCollection<L> { + fn as_ref(&self) -> &L { + &self.collection + } +} + +impl<'a, L: OwnedLockable<'a>> AsMut<L> for LockCollection<L> { + fn as_mut(&mut self) -> &mut L { + &mut self.collection + } +} + +impl<'a, L: OwnedLockable<'a>> AsRef<Self> for LockCollection<L> { + fn as_ref(&self) -> &Self { + self + } +} + +impl<'a, L: OwnedLockable<'a>> AsMut<Self> for LockCollection<L> { + fn as_mut(&mut self) -> &mut Self { + self + } +} + +impl<L: IntoIterator> IntoIterator for LockCollection<L> { + type Item = L::Item; + type IntoIter = L::IntoIter; + + fn into_iter(self) -> Self::IntoIter { + self.collection.into_iter() + } +} + +impl<'a, L> IntoIterator for &'a LockCollection<L> +where + &'a L: IntoIterator, +{ + type Item = <&'a L as IntoIterator>::Item; + type IntoIter = <&'a L as IntoIterator>::IntoIter; + + fn into_iter(self) -> Self::IntoIter { + self.collection.into_iter() + } +} + +impl<'a, L> IntoIterator for &'a mut LockCollection<L> +where + &'a mut L: IntoIterator, +{ + type Item = <&'a mut L as IntoIterator>::Item; + type IntoIter = <&'a mut L as IntoIterator>::IntoIter; + + fn into_iter(self) -> Self::IntoIter { + self.collection.into_iter() + } +} + +impl<'a, L: OwnedLockable<'a>, I: FromIterator<L> + OwnedLockable<'a>> FromIterator<L> + for LockCollection<I> +{ + fn from_iter<T: IntoIterator<Item = L>>(iter: T) -> Self { + let iter: I = iter.into_iter().collect(); + Self::new(iter) + } +} + +impl<'a, E: OwnedLockable<'a> + Extend<L>, L: OwnedLockable<'a>> Extend<L> for LockCollection<E> { + fn extend<T: IntoIterator<Item = L>>(&mut self, iter: T) { + self.collection.extend(iter) } } @@ -54,6 +120,7 @@ impl<'a, L: OwnedLockable<'a>> LockCollection<L> { /// /// Because the locks are owned, there's no need to do any checks for /// duplicate values. + #[must_use] pub const fn new(collection: L) -> Self { Self { collection } } @@ -62,11 +129,25 @@ impl<'a, L: OwnedLockable<'a>> LockCollection<L> { /// /// Because the locks are owned, there's no need to do any checks for /// duplicate values. + #[must_use] pub const fn new_ref(collection: &L) -> LockCollection<&L> { LockCollection { collection } } } +impl<L> LockCollection<L> { + /// Creates a new collections of locks. + /// + /// # Safety + /// + /// This results in undefined behavior if any locks are presented twice + /// within this collection. + #[must_use] + pub const unsafe fn new_unchecked(collection: L) -> Self { + Self { collection } + } +} + impl<'a, L: Lockable<'a>> LockCollection<L> { /// Creates a new collection of locks. /// @@ -78,6 +159,7 @@ impl<'a, L: Lockable<'a>> LockCollection<L> { /// This does a check at runtime to make sure that the collection contains /// no two copies of the same lock. This is an `O(n^2)` operation. Prefer /// [`LockCollection::new`] or [`LockCollection::new_ref`] instead. + #[must_use] pub fn try_new(collection: L) -> Option<Self> { let ptrs = collection.get_ptrs(); if contains_duplicates(&ptrs) { @@ -123,6 +205,27 @@ impl<'a, L: Lockable<'a>> LockCollection<L> { } } +impl<'a, L: 'a> LockCollection<L> +where + &'a L: IntoIterator, +{ + /// Returns an iterator over references to each value in the collection. + pub fn iter(&'a self) -> <&'a L as IntoIterator>::IntoIter { + self.into_iter() + } +} + +impl<'a, L: 'a> LockCollection<L> +where + &'a mut L: IntoIterator, +{ + /// Returns an iterator over mutable references to each value in the + /// collection. + pub fn iter_mut(&'a mut self) -> <&'a mut L as IntoIterator>::IntoIter { + self.into_iter() + } +} + impl<'a, 'key: 'a, L: Lockable<'a>, Key: Keyable> Deref for LockGuard<'a, 'key, L, Key> { type Target = L::Output; @@ -6,9 +6,10 @@ use once_cell::sync::Lazy; use thread_local::ThreadLocal; use self::sealed::Sealed; +use super::ThreadKey; mod sealed { - use super::ThreadKey; + use crate::ThreadKey; pub trait Sealed {} impl Sealed for ThreadKey {} impl Sealed for &mut ThreadKey {} @@ -16,12 +17,7 @@ mod sealed { static KEY: Lazy<ThreadLocal<AtomicLock>> = Lazy::new(ThreadLocal::new); -/// The key for the current thread. -/// -/// Only one of these exist per thread. To get the current thread's key, call -/// [`ThreadKey::lock`]. If the `ThreadKey` is dropped, it can be reobtained. -pub type ThreadKey = Key<'static>; - +/// A key that can be obtained and dropped pub struct Key<'a> { phantom: PhantomData<*const ()>, // implement !Send and !Sync lock: &'a AtomicLock, @@ -85,6 +81,7 @@ impl AtomicLock { /// /// This is not a fair lock. It is not recommended to call this function /// repeatedly in a loop. + #[must_use] pub fn try_lock(&self) -> Option<Key> { // safety: we just acquired the lock (!self.is_locked.swap(true, Ordering::Acquire)).then_some(Key { @@ -5,17 +5,22 @@ #![allow(clippy::semicolon_if_nothing_returned)] mod collection; -mod key; mod lockable; +pub mod key; pub mod mutex; pub mod rwlock; pub use collection::LockCollection; -pub use key::{Key, ThreadKey}; pub use lockable::Lockable; pub use mutex::SpinLock; +/// The key for the current thread. +/// +/// Only one of these exist per thread. To get the current thread's key, call +/// [`ThreadKey::lock`]. If the `ThreadKey` is dropped, it can be reobtained. +pub type ThreadKey = key::Key<'static>; + /// A mutual exclusion primitive useful for protecting shared data, which cannot deadlock. /// /// By default, this uses `parking_lot` as a backend. diff --git a/src/lockable.rs b/src/lockable.rs index 3c217c4..d3367fa 100644 --- a/src/lockable.rs +++ b/src/lockable.rs @@ -7,28 +7,6 @@ use crate::{ use lock_api::{RawMutex, RawRwLock}; -mod sealed { - use super::Lockable as L; - #[allow(clippy::wildcard_imports)] - use super::*; - - pub trait Sealed {} - impl<'a, T, R: RawMutex + 'a> Sealed for Mutex<T, R> {} - impl<'a, T, R: RawRwLock + 'a> Sealed for RwLock<T, R> {} - impl<'a, T, R: RawRwLock + 'a> Sealed for ReadLock<'a, T, R> {} - impl<'a, T, R: RawRwLock + 'a> Sealed for WriteLock<'a, T, R> {} - impl<T: Sealed> Sealed for &T {} - impl<T: Sealed> Sealed for &mut T {} - impl<'a, A: L<'a>> Sealed for (A,) {} - impl<'a, A: L<'a>, B: L<'a>> Sealed for (A, B) {} - impl<'a, A: L<'a>, B: L<'a>, C: L<'a>> Sealed for (A, B, C) {} - impl<'a, A: L<'a>, B: L<'a>, C: L<'a>, D: L<'a>> Sealed for (A, B, C, D) {} - impl<'a, A: L<'a>, B: L<'a>, C: L<'a>, D: L<'a>, E: L<'a>> Sealed for (A, B, C, D, E) {} - impl<'a, A: L<'a>, B: L<'a>, C: L<'a>, D: L<'a>, E: L<'a>, F: L<'a>> Sealed for (A, B, C, D, E, F) {} - impl<'a, T: Lockable<'a>, const N: usize> Sealed for [T; N] {} - impl<'a, T: Lockable<'a>> Sealed for Vec<T> {} -} - /// A type that may be locked and unlocked, and is known to be the only valid /// instance of the lock. /// @@ -45,12 +23,13 @@ pub unsafe trait OwnedLockable<'a>: Lockable<'a> {} /// A deadlock must never occur. The `unlock` method must correctly unlock the /// data. The `get_ptrs` method must be implemented correctly. The `Output` /// must be unlocked when it is dropped. -pub unsafe trait Lockable<'a>: sealed::Sealed { +pub unsafe trait Lockable<'a> { /// The output of the lock type Output; /// Returns a list of all pointers to locks. This is used to ensure that /// the same lock isn't included twice + #[must_use] fn get_ptrs(&self) -> Vec<usize>; /// Blocks until the lock is acquired @@ -62,7 +41,7 @@ pub unsafe trait Lockable<'a>: sealed::Sealed { /// which should last as long as the return value is alive. /// * Call this on multiple locks without unlocking first. /// - /// [`ThreadKey`]: `crate::key::ThreadKey` + /// [`ThreadKey`]: `crate::ThreadKey` unsafe fn lock(&'a self) -> Self::Output; /// Attempt to lock without blocking. @@ -75,7 +54,7 @@ pub unsafe trait Lockable<'a>: sealed::Sealed { /// access to the [`ThreadKey`], which should last as long as the return /// value is alive. /// - /// [`ThreadKey`]: `crate::key::ThreadKey` + /// [`ThreadKey`]: `crate::ThreadKey` unsafe fn try_lock(&'a self) -> Option<Self::Output>; } @@ -153,7 +132,7 @@ unsafe impl<'a, T: 'a, R: RawRwLock + 'a> Lockable<'a> for ReadLock<'a, T, R> { type Output = RwLockReadRef<'a, T, R>; fn get_ptrs(&self) -> Vec<usize> { - vec![self.0 as *const RwLock<T, R> as usize] + vec![self.as_ref() as *const RwLock<T, R> as usize] } unsafe fn lock(&'a self) -> Self::Output { @@ -169,7 +148,7 @@ unsafe impl<'a, T: 'a, R: RawRwLock + 'a> Lockable<'a> for WriteLock<'a, T, R> { type Output = RwLockWriteRef<'a, T, R>; fn get_ptrs(&self) -> Vec<usize> { - vec![self.0 as *const RwLock<T, R> as usize] + vec![self.as_ref() as *const RwLock<T, R> as usize] } unsafe fn lock(&'a self) -> Self::Output { @@ -562,6 +541,51 @@ unsafe impl<'a, T: Lockable<'a>, const N: usize> Lockable<'a> for [T; N] { } } +unsafe impl<'a, T: Lockable<'a>> Lockable<'a> for Box<[T]> { + type Output = Box<[T::Output]>; + + fn get_ptrs(&self) -> Vec<usize> { + let mut ptrs = Vec::with_capacity(self.len()); + for lock in &**self { + ptrs.append(&mut lock.get_ptrs()); + } + ptrs + } + + unsafe fn lock(&'a self) -> Self::Output { + 'outer: loop { + let mut outputs = Vec::with_capacity(self.len()); + if self.is_empty() { + return outputs.into_boxed_slice(); + } + + outputs.push(self[0].lock()); + for lock in self.iter().skip(1) { + if let Some(guard) = lock.try_lock() { + outputs.push(guard); + } else { + continue 'outer; + }; + } + + return outputs.into_boxed_slice(); + } + } + + unsafe fn try_lock(&'a self) -> Option<Self::Output> { + let mut outputs = Vec::with_capacity(self.len()); + for lock in &**self { + if let Some(guard) = lock.try_lock() { + outputs.push(guard); + } else { + return None; + }; + } + + Some(outputs.into_boxed_slice()) + } +} + unsafe impl<'a, T: Lockable<'a>> Lockable<'a> for Vec<T> { type Output = Vec<T::Output>; @@ -608,4 +632,5 @@ unsafe impl<'a, T: Lockable<'a>> Lockable<'a> for Vec<T> { } unsafe impl<'a, T: OwnedLockable<'a>, const N: usize> OwnedLockable<'a> for [T; N] {} +unsafe impl<'a, T: OwnedLockable<'a>> OwnedLockable<'a> for Box<[T]> {} unsafe impl<'a, T: OwnedLockable<'a>> OwnedLockable<'a> for Vec<T> {} diff --git a/src/mutex.rs b/src/mutex.rs index c78d398..e7a439c 100644 --- a/src/mutex.rs +++ b/src/mutex.rs @@ -1,4 +1,5 @@ use std::cell::UnsafeCell; +use std::fmt::Debug; use std::marker::PhantomData; use std::ops::{Deref, DerefMut}; @@ -97,6 +98,7 @@ impl<'a, 'key: 'a, T: ?Sized + 'a, Key: Keyable, R: RawMutex> DerefMut impl<'a, 'key: 'a, T: ?Sized + 'a, Key: Keyable, R: RawMutex> MutexGuard<'a, 'key, T, Key, R> { /// Create a guard to the given mutex. Undefined if multiple guards to the /// same mutex exist at once. + #[must_use] const unsafe fn new(mutex: &'a Mutex<T, R>, thread_key: Key) -> Self { Self { mutex: MutexRef(mutex), @@ -116,6 +118,7 @@ impl<T, R: RawMutex> Mutex<T, R> { /// /// let mutex = Mutex::new(0); /// ``` + #[must_use] pub const fn new(value: T) -> Self { Self { raw: R::INIT, @@ -124,6 +127,24 @@ impl<T, R: RawMutex> Mutex<T, R> { } } +impl<T: ?Sized, R> Debug for Mutex<T, R> { + fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result { + f.write_str(&format!("Mutex<{}>", std::any::type_name::<T>())) + } +} + +impl<T, R: RawMutex> From<T> for Mutex<T, R> { + fn from(value: T) -> Self { + Self::new(value) + } +} + +impl<T: ?Sized, R> AsMut<T> for Mutex<T, R> { + fn as_mut(&mut self) -> &mut T { + self.get_mut() + } +} + impl<T, R> Mutex<T, R> { /// Consumes this mutex, returning the underlying data. /// @@ -134,7 +155,8 @@ impl<T, R> Mutex<T, R> { /// /// let mutex = Mutex::new(0); /// assert_eq!(mutex.into_inner(), 0); - /// ```` + /// ``` + #[must_use] pub fn into_inner(self) -> T { self.value.into_inner() } @@ -155,7 +177,8 @@ impl<T: ?Sized, R> Mutex<T, R> { /// let mut mutex = Mutex::new(0); /// *mutex.get_mut() = 10; /// assert_eq!(*mutex.lock(key), 10); - /// ```` + /// ``` + #[must_use] pub fn get_mut(&mut self) -> &mut T { self.value.get_mut() } @@ -283,4 +306,4 @@ impl<T: ?Sized, R: RawMutex> Mutex<T, R> { } unsafe impl<R: RawMutex + Send, T: ?Sized + Send> Send for Mutex<T, R> {} -unsafe impl<R: RawMutex + Sync, T: ?Sized + Send> Sync for Mutex<T, R> {} +unsafe impl<R: RawMutex + Sync, T: ?Sized + Send + Sync> Sync for Mutex<T, R> {} diff --git a/src/rwlock.rs b/src/rwlock.rs index 722ca2f..f5f0f2b 100644 --- a/src/rwlock.rs +++ b/src/rwlock.rs @@ -1,8 +1,7 @@ -use std::{ - cell::UnsafeCell, - marker::PhantomData, - ops::{Deref, DerefMut}, -}; +use std::cell::UnsafeCell; +use std::fmt::Debug; +use std::marker::PhantomData; +use std::ops::{Deref, DerefMut}; use lock_api::RawRwLock; @@ -17,9 +16,9 @@ pub struct RwLock<T: ?Sized, R> { value: UnsafeCell<T>, } -pub struct ReadLock<'a, T: ?Sized, R>(pub(crate) &'a RwLock<T, R>); +pub struct ReadLock<'a, T: ?Sized, R>(&'a RwLock<T, R>); -pub struct WriteLock<'a, T: ?Sized, R>(pub(crate) &'a RwLock<T, R>); +pub struct WriteLock<'a, T: ?Sized, R>(&'a RwLock<T, R>); pub struct RwLockReadRef<'a, T: ?Sized, R: RawRwLock>(&'a RwLock<T, R>); @@ -37,6 +36,9 @@ pub struct RwLockWriteGuard<'a, 'key, T: ?Sized, Key: Keyable + 'key, R: RawRwLo _phantom: PhantomData<&'key ()>, } +unsafe impl<R: RawRwLock + Send, T: ?Sized + Send> Send for RwLock<T, R> {} +unsafe impl<R: RawRwLock + Sync, T: ?Sized + Send + Sync> Sync for RwLock<T, R> {} + impl<'a, T: ?Sized + 'a, R: RawRwLock> Deref for RwLockReadRef<'a, T, R> { type Target = T; @@ -117,6 +119,7 @@ impl<'a, 'key: 'a, T: ?Sized + 'a, Key: Keyable, R: RawRwLock> { /// Create a guard to the given mutex. Undefined if multiple guards to the /// same mutex exist at once. + #[must_use] const unsafe fn new(rwlock: &'a RwLock<T, R>, thread_key: Key) -> Self { Self { rwlock: RwLockReadRef(rwlock), @@ -131,6 +134,7 @@ impl<'a, 'key: 'a, T: ?Sized + 'a, Key: Keyable, R: RawRwLock> { /// Create a guard to the given mutex. Undefined if multiple guards to the /// same mutex exist at once. + #[must_use] const unsafe fn new(rwlock: &'a RwLock<T, R>, thread_key: Key) -> Self { Self { rwlock: RwLockWriteRef(rwlock), @@ -141,6 +145,7 @@ impl<'a, 'key: 'a, T: ?Sized + 'a, Key: Keyable, R: RawRwLock> } impl<T, R: RawRwLock> RwLock<T, R> { + #[must_use] pub const fn new(value: T) -> Self { Self { value: UnsafeCell::new(value), @@ -149,6 +154,60 @@ impl<T, R: RawRwLock> RwLock<T, R> { } } +impl<T: ?Sized, R> Debug for RwLock<T, R> { + fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result { + f.write_str(&format!("RwLock<{}>", std::any::type_name::<T>())) + } +} + +impl<T, R: RawRwLock> From<T> for RwLock<T, R> { + fn from(value: T) -> Self { + Self::new(value) + } +} + +impl<T: ?Sized, R> AsMut<T> for RwLock<T, R> { + fn as_mut(&mut self) -> &mut T { + self.get_mut() + } +} + +impl<'a, T: ?Sized, R> Debug for ReadLock<'a, T, R> { + fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result { + f.write_str(&format!("ReadLock<{}>", std::any::type_name::<T>())) + } +} + +impl<'a, T: ?Sized, R> From<&'a RwLock<T, R>> for ReadLock<'a, T, R> { + fn from(value: &'a RwLock<T, R>) -> Self { + Self::new(value) + } +} + +impl<'a, T: ?Sized, R> AsRef<RwLock<T, R>> for ReadLock<'a, T, R> { + fn as_ref(&self) -> &RwLock<T, R> { + self.0 + } +} + +impl<'a, T: ?Sized, R> Debug for WriteLock<'a, T, R> { + fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result { + f.write_str(&format!("WriteLock<{}>", std::any::type_name::<T>())) + } +} + +impl<'a, T: ?Sized, R> From<&'a RwLock<T, R>> for WriteLock<'a, T, R> { + fn from(value: &'a RwLock<T, R>) -> Self { + Self::new(value) + } +} + +impl<'a, T: ?Sized, R> AsRef<RwLock<T, R>> for WriteLock<'a, T, R> { + fn as_ref(&self) -> &RwLock<T, R> { + self.0 + } +} + impl<T, R> RwLock<T, R> { pub fn into_inner(self) -> T { self.value.into_inner() @@ -273,7 +332,8 @@ impl<T: ?Sized, R: RawRwLock> RwLock<T, R> { } } -impl<'a, T, R> ReadLock<'a, T, R> { +impl<'a, T: ?Sized, R> ReadLock<'a, T, R> { + #[must_use] pub const fn new(rwlock: &'a RwLock<T, R>) -> Self { Self(rwlock) } @@ -307,7 +367,8 @@ impl<'a, T: ?Sized, R: RawRwLock> ReadLock<'a, T, R> { } } -impl<'a, T, R> WriteLock<'a, T, R> { +impl<'a, T: ?Sized, R> WriteLock<'a, T, R> { + #[must_use] pub const fn new(rwlock: &'a RwLock<T, R>) -> Self { Self(rwlock) } |