Linked lists that supports arbitrary removal in constant time.
+It is based on the linked list implementation in Rust-for-Linux.
+Redirecting to ../../linked_list/struct.List.html...
+ + + \ No newline at end of file diff --git a/linked_list/linked_list/trait.AdapterWrapped.html b/linked_list/linked_list/trait.AdapterWrapped.html new file mode 100644 index 0000000..4c41ad3 --- /dev/null +++ b/linked_list/linked_list/trait.AdapterWrapped.html @@ -0,0 +1,11 @@ + + + + +Redirecting to ../../linked_list/trait.AdapterWrapped.html...
+ + + \ No newline at end of file diff --git a/linked_list/linked_list/trait.Wrapper.html b/linked_list/linked_list/trait.Wrapper.html new file mode 100644 index 0000000..472ca95 --- /dev/null +++ b/linked_list/linked_list/trait.Wrapper.html @@ -0,0 +1,11 @@ + + + + +Redirecting to ../../linked_list/trait.Wrapper.html...
+ + + \ No newline at end of file diff --git a/linked_list/sidebar-items.js b/linked_list/sidebar-items.js new file mode 100644 index 0000000..c7df4b5 --- /dev/null +++ b/linked_list/sidebar-items.js @@ -0,0 +1 @@ +window.SIDEBAR_ITEMS = {"mod":["unsafe_list"],"struct":["List"],"trait":["AdapterWrapped","Wrapper"]}; \ No newline at end of file diff --git a/linked_list/struct.List.html b/linked_list/struct.List.html new file mode 100644 index 0000000..d51adde --- /dev/null +++ b/linked_list/struct.List.html @@ -0,0 +1,41 @@ +pub struct List<G: AdapterWrapped> { /* private fields */ }A linked list.
+Elements in the list are wrapped and ownership is transferred to the list while the element is +in the list.
+Adds the given object to the end (back) of the list.
+It is dropped if it’s already on this (or another) list; this can happen for +reference-counted objects, so dropping means decrementing the reference count.
+Inserts the given object after existing.
It is dropped if it’s already on this (or another) list; this can happen for +reference-counted objects, so dropping means decrementing the reference count.
+Callers must ensure that existing points to a valid entry that is on the list.
Removes the given entry.
+Callers must ensure that data is either on this list. It being on another
+list leads to memory unsafety.
Removes the element currently at the front of the list and returns it.
+Returns None if the list is empty.
Returns the first element of the list, if one exists.
+Returns the last element of the list, if one exists.
+Returns a cursor starting on the first (front) element of the list.
+pub trait AdapterWrapped: Adapter {
+ type Wrapped: Wrapper<Self::EntryType>;
+}A descriptor of wrapped list elements.
+pub trait Wrapper<T: ?Sized> {
+ // Required methods
+ fn into_pointer(self) -> NonNull<T>;
+ unsafe fn from_pointer(ptr: NonNull<T>) -> Self;
+ fn as_ref(&self) -> &T;
+}Wraps an object to be inserted in a linked list.
+Converts the wrapped object into a pointer that represents it.
+Converts the object back from the pointer representation.
+The passed pointer must come from a previous call to Wrapper::into_pointer().
Intrusive circular doubly-linked lists.
+Copied from linux/rust/kernel/unsafe_list.rs.
+We don’t use the C version for two main reasons:
+?Sized types, so wouldn’t be able to have a list of, for
+example, dyn Trait.pub struct Cursor<'a, A: Adapter + ?Sized> { /* private fields */ }A list cursor that allows traversing a linked list and inspecting elements.
+pub struct Iterator<'a, A: Adapter + ?Sized> { /* private fields */ }An iterator for the linked list.
+iter_advance_by)n elements. Read morenth element from the end of the iterator. Read moreIterator::try_fold(): it takes
+elements starting from the back of the iterator. Read moreiter_next_chunk)N values. Read moreiter_advance_by)n elements. Read morenth element of the iterator. Read moreiter_intersperse)separator
+between adjacent items of the original iterator. Read moren elements. Read moren elements, or fewer
+if the underlying iterator ends sooner. Read moreiter_map_windows)f for each contiguous window of size N over
+self and returns an iterator over the outputs of f. Like slice::windows(),
+the windows during mapping overlap as well. Read moreiter_collect_into)iter_partition_in_place)true precede all those that return false.
+Returns the number of true elements found. Read moreiter_is_partitioned)true precede all those that return false. Read moreiterator_try_reduce)try_find)iter_array_chunks)N elements of the iterator at a time. Read moreiter_order_by)Iterator with those
+of another with respect to the specified comparison function. Read morePartialOrd elements of
+this Iterator with those of another. The comparison works like short-circuit
+evaluation, returning a result without comparing the remaining elements.
+As soon as an order can be determined, the evaluation stops and a result is returned. Read moreiter_order_by)Iterator with those
+of another with respect to the specified comparison function. Read moreiter_order_by)Iterator are lexicographically
+less than those of another. Read moreIterator are lexicographically
+less or equal to those of another. Read moreIterator are lexicographically
+greater than those of another. Read moreIterator are lexicographically
+greater than or equal to those of another. Read moreis_sorted)is_sorted)pub struct Links<T: ?Sized>(/* private fields */);Links of a linked list.
+List entries need one of these per concurrent list.
+pub struct List<A: Adapter + ?Sized> { /* private fields */ }An intrusive circular doubly-linked list.
+Membership of elements of the list must be tracked by the owner of the list.
+While elements of the list must remain pinned while in the list, the list itself does not
+require pinning. In other words, users are allowed to move instances of List.
The links of an entry are wrapped in UnsafeCell and they are acessible when the list itself
+is. For example, when a thread has a mutable reference to a list, it may also safely get
+mutable references to the links of the elements in the list.
The links of an entry are also wrapped in MaybeUninit and they are initialised when they
+are present in a list. Otherwise they are uninitialised.
+struct Example {
+ v: usize,
+ links: Links<Example>,
+}
+
+// SAFETY: This adapter is the only one that uses `Example::links`.
+unsafe impl Adapter for Example {
+ type EntryType = Self;
+ fn to_links(obj: &Self) -> &Links<Self> {
+ &obj.links
+ }
+}
+
+let a = Example {
+ v: 0,
+ links: Links::new(),
+};
+let b = Example {
+ v: 1,
+ links: Links::new(),
+};
+
+let mut list = List::<Example>::new();
+assert!(list.is_empty());
+
+// SAFETY: `a` was declared above, it's not in any lists yet, is never moved, and outlives the
+// list.
+unsafe { list.push_back(&a) };
+
+// SAFETY: `b` was declared above, it's not in any lists yet, is never moved, and outlives the
+// list.
+unsafe { list.push_back(&b) };
+
+assert!(core::ptr::eq(&a, list.front().unwrap().as_ptr()));
+assert!(core::ptr::eq(&b, list.back().unwrap().as_ptr()));
+
+for (i, e) in list.iter().enumerate() {
+ assert_eq!(i, e.v);
+}
+
+for e in &list {
+ println!("{}", e.v);
+}
+
+// SAFETY: `b` was added to the list above and wasn't removed yet.
+unsafe { list.remove(&b) };
+
+assert!(core::ptr::eq(&a, list.front().unwrap().as_ptr()));
+assert!(core::ptr::eq(&a, list.back().unwrap().as_ptr()));Inserts the only entry to a list.
+This must only be called when the list is empty.
+Adds the given object to the end of the list.
+Callers must ensure that:
+Adds the given object to the beginning of the list.
+Callers must ensure that:
+Removes the given object from the list.
+The object must be in the list. In other words, the object must have previously been +inserted into this list and not removed yet.
+Adds the given object after another object already in the list.
+Callers must ensure that:
+Adds the given object before another object already in the list.
+Callers must ensure that:
+Returns the first element of the list, if one exists.
+Returns the last element of the list, if one exists.
+Returns an iterator for the list starting at the first entry.
+Returns an iterator for the list starting at the last entry.
+Returns a cursor starting on the first (front) element of the list.
+Returns a cursor starting on the last (back) element of the list.
+pub unsafe trait Adapter {
+ type EntryType: ?Sized;
+
+ // Required method
+ fn to_links(obj: &Self::EntryType) -> &Links<Self::EntryType>;
+}A linked-list adapter.
+It is a separate type (as opposed to implemented by the type of the elements of the list) +so that a given type can be inserted into multiple lists at the same time; in such cases, each +list needs its own adapter that returns a different pointer to links.
+It may, however, be implemented by the type itself to be inserted into lists, which makes it +more readable.
+Implementers must ensure that the links returned by Adapter::to_links are unique to the
+adapter. That is, different adapters must return different links for a given object.
The reason for this requirement is to avoid confusion that may lead to UB. In particular, if
+two adapters were to use the same links, a user may have two lists (one for each adapter) and
+try to insert the same object into both at the same time; although this clearly violates the
+list safety requirements (e.g., those in List::push_back), for users to notice it, they’d
+have to dig into the details of the two adapters.
By imposing the requirement on the adapter, we make it easier for users to check compliance +with the requirements when using the list.
+
+struct Example {
+ a: u32,
+ b: u32,
+ links1: Links<Example>,
+ links2: Links<Example>,
+}
+
+// SAFETY: This adapter is the only one that uses `Example::links1`.
+unsafe impl Adapter for Example {
+ type EntryType = Self;
+ fn to_links(obj: &Self) -> &Links<Self> {
+ &obj.links1
+ }
+}
+
+struct ExampleAdapter;
+
+// SAFETY: This adapter is the only one that uses `Example::links2`.
+unsafe impl Adapter for ExampleAdapter {
+ type EntryType = Example;
+ fn to_links(obj: &Example) -> &Links<Example> {
+ &obj.links2
+ }
+}
+
+static LIST1: List<Example> = List::new();
+static LIST2: List<ExampleAdapter> = List::new();Box and Arc) wraps the list …\nWraps an object to be inserted in a linked list.\nReturns a reference to the wrapped object.\nReturns the last element of the list, if one exists.\nReturns a cursor starting on the first (front) element of …\nReturns the argument unchanged.\nConverts the object back from the pointer representation.\nReturns the first element of the list, if one exists.\nInserts the given object after existing.\nCalls U::from(self).\nConverts the wrapped object into a pointer that represents …\nReturns whether the list is empty.\nConstructs a new empty linked list.\nRemoves the element currently at the front of the list and …\nAdds the given object to the end (back) of the list.\nRemoves the given entry.\nIntrusive circular doubly-linked lists.\nA linked-list adapter.\nA list cursor that allows traversing a linked list and …\nThe type of the enties in the list.\nAn iterator for the linked list.\nLinks of a linked list.\nAn intrusive circular doubly-linked list.\nReturns the last element of the list, if one exists.\nReturns the element the cursor is currently positioned on.\nReturns a cursor starting on the last (back) element of …\nReturns a cursor starting on the first (front) element of …\nReturns the argument unchanged.\nReturns the argument unchanged.\nReturns the argument unchanged.\nReturns the argument unchanged.\nReturns the first element of the list, if one exists.\nAdds the given object after another object already in the …\nAdds the given object before another object already in the …\nInserts the only entry to a list.\nCalls U::from(self).\nCalls U::from(self).\nCalls U::from(self).\nCalls U::from(self).\nDetermines if the list is empty.\nReturns an iterator for the list starting at the first …\nReturns an iterator for the list starting at the last …\nMoves the cursor to the next element.\nMoves the cursor to the previous element.\nConstructs a new empty list.\nConstructs a new instance of the linked-list links.\nAdds the given object to the end of the list.\nAdds the given object to the beginning of the list.\nRemoves the given object from the list.\nRetrieves the linked list links for the given object.")
\ No newline at end of file
diff --git a/settings.html b/settings.html
new file mode 100644
index 0000000..61f4016
--- /dev/null
+++ b/settings.html
@@ -0,0 +1 @@
+//! Linked lists that supports arbitrary removal in constant time.
+//!
+//! It is based on the linked list implementation in [Rust-for-Linux][1].
+//!
+//! [1]: https://github.com/Rust-for-Linux/linux/blob/rust/rust/kernel/linked_list.rs
+
+#![no_std]
+
+mod linked_list;
+
+pub mod unsafe_list;
+
+pub use self::linked_list::{AdapterWrapped, List, Wrapper};
+pub use unsafe_list::{Adapter, Cursor, Links};
+1 +2 +3 +4 +5 +6 +7 +8 +9 +10 +11 +12 +13 +14 +15 +16 +17 +18 +19 +20 +21 +22 +23 +24 +25 +26 +27 +28 +29 +30 +31 +32 +33 +34 +35 +36 +37 +38 +39 +40 +41 +42 +43 +44 +45 +46 +47 +48 +49 +50 +51 +52 +53 +54 +55 +56 +57 +58 +59 +60 +61 +62 +63 +64 +65 +66 +67 +68 +69 +70 +71 +72 +73 +74 +75 +76 +77 +78 +79 +80 +81 +82 +83 +84 +85 +86 +87 +88 +89 +90 +91 +92 +93 +94 +95 +96 +97 +98 +99 +100 +101 +102 +103 +104 +105 +106 +107 +108 +109 +110 +111 +112 +113 +114 +115 +116 +117 +118 +119 +120 +121 +122 +123 +124 +125 +126 +127 +128 +129 +130 +131 +132 +133 +134 +135 +136 +137 +138 +139 +140 +141 +142 +143 +144 +145 +146 +147 +148 +149 +150 +151 +152 +153 +154 +155 +156 +157 +158 +159 +160 +161 +162 +163 +164 +165 +166 +167 +168 +169 +170 +171 +172 +173 +174 +175 +176 +177 +178 +179 +180 +181 +182 +183 +184 +185 +186 +187 +188 +189 +190 +191 +192 +193 +194 +195 +196 +197 +198 +199 +200 +201 +202 +203 +204 +205 +206 +207 +208 +209 +210 +211 +212 +213 +214 +215 +216 +217 +218 +219 +220 +
// SPDX-License-Identifier: GPL-2.0
+
+//! Linked lists.
+//!
+//! Based on linux/rust/kernel/linked_list.rs, but use
+//! [`unsafe_list::List`] as the inner implementation.
+//!
+//! TODO: This module is a work in progress.
+
+extern crate alloc;
+
+use alloc::{boxed::Box, sync::Arc};
+use core::ptr::NonNull;
+
+use crate::unsafe_list::{self, Adapter, Cursor, Links};
+
+// TODO: Use the one from `kernel::file_operations::PointerWrapper` instead.
+/// Wraps an object to be inserted in a linked list.
+pub trait Wrapper<T: ?Sized> {
+ /// Converts the wrapped object into a pointer that represents it.
+ fn into_pointer(self) -> NonNull<T>;
+
+ /// Converts the object back from the pointer representation.
+ ///
+ /// # Safety
+ ///
+ /// The passed pointer must come from a previous call to [`Wrapper::into_pointer()`].
+ unsafe fn from_pointer(ptr: NonNull<T>) -> Self;
+
+ /// Returns a reference to the wrapped object.
+ fn as_ref(&self) -> &T;
+}
+
+impl<T: ?Sized> Wrapper<T> for Box<T> {
+ #[inline]
+ fn into_pointer(self) -> NonNull<T> {
+ NonNull::new(Box::into_raw(self)).unwrap()
+ }
+
+ #[inline]
+ unsafe fn from_pointer(ptr: NonNull<T>) -> Self {
+ unsafe { Box::from_raw(ptr.as_ptr()) }
+ }
+
+ #[inline]
+ fn as_ref(&self) -> &T {
+ AsRef::as_ref(self)
+ }
+}
+
+impl<T: ?Sized> Wrapper<T> for Arc<T> {
+ #[inline]
+ fn into_pointer(self) -> NonNull<T> {
+ NonNull::new(Arc::into_raw(self) as _).unwrap()
+ }
+
+ #[inline]
+ unsafe fn from_pointer(ptr: NonNull<T>) -> Self {
+ // SAFETY: The safety requirements of `from_pointer` satisfy the ones from `Arc::from_raw`.
+ unsafe { Arc::from_raw(ptr.as_ptr() as _) }
+ }
+
+ #[inline]
+ fn as_ref(&self) -> &T {
+ AsRef::as_ref(self)
+ }
+}
+
+impl<T: ?Sized> Wrapper<T> for &T {
+ #[inline]
+ fn into_pointer(self) -> NonNull<T> {
+ NonNull::from(self)
+ }
+
+ #[inline]
+ unsafe fn from_pointer(ptr: NonNull<T>) -> Self {
+ unsafe { &*ptr.as_ptr() }
+ }
+
+ #[inline]
+ fn as_ref(&self) -> &T {
+ self
+ }
+}
+
+/// A descriptor of wrapped list elements.
+pub trait AdapterWrapped: Adapter {
+ /// Specifies which wrapper (e.g., `Box` and `Arc`) wraps the list entries.
+ type Wrapped: Wrapper<Self::EntryType>;
+}
+
+impl<T: ?Sized> AdapterWrapped for Box<T>
+where
+ Box<T>: Adapter,
+{
+ type Wrapped = Box<<Box<T> as Adapter>::EntryType>;
+}
+
+unsafe impl<T: Adapter + ?Sized> Adapter for Box<T> {
+ type EntryType = T::EntryType;
+
+ #[inline]
+ fn to_links(data: &Self::EntryType) -> &Links<Self::EntryType> {
+ <T as Adapter>::to_links(data)
+ }
+}
+
+impl<T: ?Sized> AdapterWrapped for Arc<T>
+where
+ Arc<T>: Adapter,
+{
+ type Wrapped = Arc<<Arc<T> as Adapter>::EntryType>;
+}
+
+unsafe impl<T: Adapter + ?Sized> Adapter for Arc<T> {
+ type EntryType = T::EntryType;
+
+ #[inline]
+ fn to_links(data: &Self::EntryType) -> &Links<Self::EntryType> {
+ <T as Adapter>::to_links(data)
+ }
+}
+
+/// A linked list.
+///
+/// Elements in the list are wrapped and ownership is transferred to the list while the element is
+/// in the list.
+pub struct List<G: AdapterWrapped> {
+ list: unsafe_list::List<G>,
+}
+
+impl<G: AdapterWrapped> List<G> {
+ /// Constructs a new empty linked list.
+ pub const fn new() -> Self {
+ Self {
+ list: unsafe_list::List::new(),
+ }
+ }
+
+ /// Returns whether the list is empty.
+ #[inline]
+ pub const fn is_empty(&self) -> bool {
+ self.list.is_empty()
+ }
+
+ /// Adds the given object to the end (back) of the list.
+ ///
+ /// It is dropped if it's already on this (or another) list; this can happen for
+ /// reference-counted objects, so dropping means decrementing the reference count.
+ pub fn push_back(&mut self, data: G::Wrapped) {
+ let ptr = data.into_pointer();
+
+ // SAFETY: We took ownership of the entry, so it is safe to insert it.
+ unsafe { self.list.push_back(ptr.as_ref()) }
+ }
+
+ /// Inserts the given object after `existing`.
+ ///
+ /// It is dropped if it's already on this (or another) list; this can happen for
+ /// reference-counted objects, so dropping means decrementing the reference count.
+ ///
+ /// # Safety
+ ///
+ /// Callers must ensure that `existing` points to a valid entry that is on the list.
+ pub unsafe fn insert_after(&mut self, existing: NonNull<G::EntryType>, data: G::Wrapped) {
+ let ptr = data.into_pointer();
+ unsafe { self.list.insert_after(existing, ptr.as_ref()) }
+ }
+
+ /// Removes the given entry.
+ ///
+ /// # Safety
+ ///
+ /// Callers must ensure that `data` is either on this list. It being on another
+ /// list leads to memory unsafety.
+ pub unsafe fn remove(&mut self, data: &G::Wrapped) -> Option<G::Wrapped> {
+ let entry_ref = Wrapper::as_ref(data);
+ unsafe { self.list.remove(entry_ref) };
+ Some(unsafe { G::Wrapped::from_pointer(NonNull::from(entry_ref)) })
+ }
+
+ /// Removes the element currently at the front of the list and returns it.
+ ///
+ /// Returns `None` if the list is empty.
+ pub fn pop_front(&mut self) -> Option<G::Wrapped> {
+ let entry_ref = unsafe { self.list.front()?.as_ref() };
+ unsafe { self.list.remove(entry_ref) };
+ Some(unsafe { G::Wrapped::from_pointer(NonNull::from(entry_ref)) })
+ }
+
+ /// Returns the first element of the list, if one exists.
+ #[inline]
+ pub fn front(&self) -> Option<&G::EntryType> {
+ self.list.front().map(|ptr| unsafe { ptr.as_ref() })
+ }
+
+ /// Returns the last element of the list, if one exists.
+ #[inline]
+ pub fn back(&self) -> Option<&G::EntryType> {
+ self.list.back().map(|ptr| unsafe { ptr.as_ref() })
+ }
+
+ /// Returns a cursor starting on the first (front) element of the list.
+ #[inline]
+ pub fn cursor_front(&self) -> Cursor<'_, G> {
+ self.list.cursor_front()
+ }
+}
+
+impl<G: AdapterWrapped> Default for List<G> {
+ fn default() -> Self {
+ Self::new()
+ }
+}
+
+impl<G: AdapterWrapped> Drop for List<G> {
+ fn drop(&mut self) {
+ while self.pop_front().is_some() {}
+ }
+}
+1 +2 +3 +4 +5 +6 +7 +8 +9 +10 +11 +12 +13 +14 +15 +16 +17 +18 +19 +20 +21 +22 +23 +24 +25 +26 +27 +28 +29 +30 +31 +32 +33 +34 +35 +36 +37 +38 +39 +40 +41 +42 +43 +44 +45 +46 +47 +48 +49 +50 +51 +52 +53 +54 +55 +56 +57 +58 +59 +60 +61 +62 +63 +64 +65 +66 +67 +68 +69 +70 +71 +72 +73 +74 +75 +76 +77 +78 +79 +80 +81 +82 +83 +84 +85 +86 +87 +88 +89 +90 +91 +92 +93 +94 +95 +96 +97 +98 +99 +100 +101 +102 +103 +104 +105 +106 +107 +108 +109 +110 +111 +112 +113 +114 +115 +116 +117 +118 +119 +120 +121 +122 +123 +124 +125 +126 +127 +128 +129 +130 +131 +132 +133 +134 +135 +136 +137 +138 +139 +140 +141 +142 +143 +144 +145 +146 +147 +148 +149 +150 +151 +152 +153 +154 +155 +156 +157 +158 +159 +160 +161 +162 +163 +164 +165 +166 +167 +168 +169 +170 +171 +172 +173 +174 +175 +176 +177 +178 +179 +180 +181 +182 +183 +184 +185 +186 +187 +188 +189 +190 +191 +192 +193 +194 +195 +196 +197 +198 +199 +200 +201 +202 +203 +204 +205 +206 +207 +208 +209 +210 +211 +212 +213 +214 +215 +216 +217 +218 +219 +220 +221 +222 +223 +224 +225 +226 +227 +228 +229 +230 +231 +232 +233 +234 +235 +236 +237 +238 +239 +240 +241 +242 +243 +244 +245 +246 +247 +248 +249 +250 +251 +252 +253 +254 +255 +256 +257 +258 +259 +260 +261 +262 +263 +264 +265 +266 +267 +268 +269 +270 +271 +272 +273 +274 +275 +276 +277 +278 +279 +280 +281 +282 +283 +284 +285 +286 +287 +288 +289 +290 +291 +292 +293 +294 +295 +296 +297 +298 +299 +300 +301 +302 +303 +304 +305 +306 +307 +308 +309 +310 +311 +312 +313 +314 +315 +316 +317 +318 +319 +320 +321 +322 +323 +324 +325 +326 +327 +328 +329 +330 +331 +332 +333 +334 +335 +336 +337 +338 +339 +340 +341 +342 +343 +344 +345 +346 +347 +348 +349 +350 +351 +352 +353 +354 +355 +356 +357 +358 +359 +360 +361 +362 +363 +364 +365 +366 +367 +368 +369 +370 +371 +372 +373 +374 +375 +376 +377 +378 +379 +380 +381 +382 +383 +384 +385 +386 +387 +388 +389 +390 +391 +392 +393 +394 +395 +396 +397 +398 +399 +400 +401 +402 +403 +404 +405 +406 +407 +408 +409 +410 +411 +412 +413 +414 +415 +416 +417 +418 +419 +420 +421 +422 +423 +424 +425 +426 +427 +428 +429 +430 +431 +432 +433 +434 +435 +436 +437 +438 +439 +440 +441 +442 +443 +444 +445 +446 +447 +448 +449 +450 +451 +452 +453 +454 +455 +456 +457 +458 +459 +460 +461 +462 +463 +464 +465 +466 +467 +468 +469 +470 +471 +472 +473 +474 +475 +476 +477 +478 +479 +480 +481 +482 +483 +484 +485 +486 +487 +488 +489 +490 +491 +492 +493 +494 +495 +496 +497 +498 +499 +500 +501 +502 +503 +504 +505 +506 +507 +508 +509 +510 +511 +512 +513 +514 +515 +516 +517 +518 +519 +520 +521 +522 +523 +524 +525 +526 +527 +528 +529 +530 +531 +532 +533 +534 +535 +536 +537 +538 +539 +540 +541 +542 +543 +544 +545 +546 +547 +548 +549 +550 +551 +552 +553 +554 +555 +556 +557 +558 +559 +560 +561 +562 +563 +564 +565 +566 +567 +568 +569 +570 +571 +572 +573 +574 +575 +576 +577 +578 +579 +580 +581 +582 +583 +584 +585 +586 +587 +588 +589 +590 +591 +592 +593 +594 +595 +596 +597 +598 +599 +600 +601 +602 +603 +604 +605 +606 +607 +608 +609 +610 +611 +612 +613 +614 +615 +616 +617 +618 +619 +620 +621 +622 +623 +624 +625 +626 +627 +628 +629 +630 +631 +632 +633 +634 +635 +636 +637 +638 +639 +640 +641 +642 +643 +644 +645 +646 +647 +648 +649 +650 +651 +652 +653 +654 +655 +656 +657 +658 +659 +660 +661 +662 +663 +664 +665 +666 +667 +668 +669 +670 +671 +672 +673 +674 +675 +676 +677 +678 +679 +680 +681 +682 +683 +
// SPDX-License-Identifier: GPL-2.0
+
+//! Intrusive circular doubly-linked lists.
+//!
+//! Copied from linux/rust/kernel/unsafe_list.rs.
+//!
+//! We don't use the C version for two main reasons:
+//! - Next/prev pointers do not support `?Sized` types, so wouldn't be able to have a list of, for
+//! example, `dyn Trait`.
+//! - It would require the list head to be pinned (in addition to the list entries).
+
+use core::{cell::UnsafeCell, iter, marker::PhantomPinned, mem::MaybeUninit, ptr::NonNull};
+
+/// An intrusive circular doubly-linked list.
+///
+/// Membership of elements of the list must be tracked by the owner of the list.
+///
+/// While elements of the list must remain pinned while in the list, the list itself does not
+/// require pinning. In other words, users are allowed to move instances of [`List`].
+///
+/// # Invariants
+///
+/// The links of an entry are wrapped in [`UnsafeCell`] and they are acessible when the list itself
+/// is. For example, when a thread has a mutable reference to a list, it may also safely get
+/// mutable references to the links of the elements in the list.
+///
+/// The links of an entry are also wrapped in [`MaybeUninit`] and they are initialised when they
+/// are present in a list. Otherwise they are uninitialised.
+///
+/// # Examples
+///
+/// ```
+/// # use linked_list::unsafe_list::{Adapter, Links, List};
+///
+/// struct Example {
+/// v: usize,
+/// links: Links<Example>,
+/// }
+///
+/// // SAFETY: This adapter is the only one that uses `Example::links`.
+/// unsafe impl Adapter for Example {
+/// type EntryType = Self;
+/// fn to_links(obj: &Self) -> &Links<Self> {
+/// &obj.links
+/// }
+/// }
+///
+/// let a = Example {
+/// v: 0,
+/// links: Links::new(),
+/// };
+/// let b = Example {
+/// v: 1,
+/// links: Links::new(),
+/// };
+///
+/// let mut list = List::<Example>::new();
+/// assert!(list.is_empty());
+///
+/// // SAFETY: `a` was declared above, it's not in any lists yet, is never moved, and outlives the
+/// // list.
+/// unsafe { list.push_back(&a) };
+///
+/// // SAFETY: `b` was declared above, it's not in any lists yet, is never moved, and outlives the
+/// // list.
+/// unsafe { list.push_back(&b) };
+///
+/// assert!(core::ptr::eq(&a, list.front().unwrap().as_ptr()));
+/// assert!(core::ptr::eq(&b, list.back().unwrap().as_ptr()));
+///
+/// for (i, e) in list.iter().enumerate() {
+/// assert_eq!(i, e.v);
+/// }
+///
+/// for e in &list {
+/// println!("{}", e.v);
+/// }
+///
+/// // SAFETY: `b` was added to the list above and wasn't removed yet.
+/// unsafe { list.remove(&b) };
+///
+/// assert!(core::ptr::eq(&a, list.front().unwrap().as_ptr()));
+/// assert!(core::ptr::eq(&a, list.back().unwrap().as_ptr()));
+/// ```
+pub struct List<A: Adapter + ?Sized> {
+ first: Option<NonNull<A::EntryType>>,
+}
+
+// SAFETY: The list is itself can be safely sent to other threads but we restrict it to being `Send`
+// only when its entries are also `Send`.
+unsafe impl<A: Adapter + ?Sized> Send for List<A> where A::EntryType: Send {}
+
+// SAFETY: The list is itself usable from other threads via references but we restrict it to being
+// `Sync` only when its entries are also `Sync`.
+unsafe impl<A: Adapter + ?Sized> Sync for List<A> where A::EntryType: Sync {}
+
+impl<A: Adapter + ?Sized> List<A> {
+ /// Constructs a new empty list.
+ pub const fn new() -> Self {
+ Self { first: None }
+ }
+
+ /// Determines if the list is empty.
+ pub const fn is_empty(&self) -> bool {
+ self.first.is_none()
+ }
+
+ /// Inserts the only entry to a list.
+ ///
+ /// This must only be called when the list is empty.
+ pub fn insert_only_entry(&mut self, obj: &A::EntryType) {
+ let obj_ptr = NonNull::from(obj);
+
+ // SAFETY: We have mutable access to the list, so we also have access to the entry
+ // we're about to insert (and it's not in any other lists per the function safety
+ // requirements).
+ let obj_inner = unsafe { &mut *A::to_links(obj).0.get() };
+
+ // INVARIANTS: All fields of the links of the newly-inserted object are initialised
+ // below.
+ obj_inner.write(LinksInner {
+ next: obj_ptr,
+ prev: obj_ptr,
+ _pin: PhantomPinned,
+ });
+ self.first = Some(obj_ptr);
+ }
+
+ /// Adds the given object to the end of the list.
+ ///
+ /// # Safety
+ ///
+ /// Callers must ensure that:
+ /// - The object is not currently in any lists.
+ /// - The object remains alive until it is removed from the list.
+ /// - The object is not moved until it is removed from the list.
+ pub unsafe fn push_back(&mut self, obj: &A::EntryType) {
+ if let Some(first) = self.first {
+ // SAFETY: The previous entry to the first one is necessarily present in the list (it
+ // may in fact be the first entry itself as this is a circular list). The safety
+ // requirements of this function regarding `obj` satisfy those of `insert_after`.
+ unsafe { self.insert_after(self.inner_ref(first).prev, obj) };
+ } else {
+ self.insert_only_entry(obj);
+ }
+ }
+
+ /// Adds the given object to the beginning of the list.
+ ///
+ /// # Safety
+ ///
+ /// Callers must ensure that:
+ /// - The object is not currently in any lists.
+ /// - The object remains alive until it is removed from the list.
+ /// - The object is not moved until it is removed from the list.
+ pub unsafe fn push_front(&mut self, obj: &A::EntryType) {
+ if let Some(first) = self.first {
+ // SAFETY: The safety requirements of this function regarding `obj` satisfy those of
+ // `insert_before`. Additionally, `first` is in the list.
+ unsafe { self.insert_before(first, obj) };
+ } else {
+ self.insert_only_entry(obj);
+ }
+ }
+
+ /// Removes the given object from the list.
+ ///
+ /// # Safety
+ ///
+ /// The object must be in the list. In other words, the object must have previously been
+ /// inserted into this list and not removed yet.
+ pub unsafe fn remove(&mut self, entry: &A::EntryType) {
+ // SAFETY: Per the function safety requirements, `entry` is in the list.
+ let inner = unsafe { self.inner_ref(NonNull::from(entry)) };
+ let next = inner.next;
+ let prev = inner.prev;
+
+ // SAFETY: We have mutable access to the list, so we also have access to the entry we're
+ // about to remove (which we know is in the list per the function safety requirements).
+ let inner = unsafe { &mut *A::to_links(entry).0.get() };
+
+ // SAFETY: Since the entry was in the list, it was initialised.
+ unsafe { inner.assume_init_drop() };
+
+ if core::ptr::eq(next.as_ptr(), entry) {
+ // Removing the only element.
+ self.first = None;
+ } else {
+ // SAFETY: `prev` is in the list because it is pointed at by the entry being removed.
+ unsafe { self.inner(prev).next = next };
+ // SAFETY: `next` is in the list because it is pointed at by the entry being removed.
+ unsafe { self.inner(next).prev = prev };
+
+ if core::ptr::eq(self.first.unwrap().as_ptr(), entry) {
+ // Update the pointer to the first element as we're removing it.
+ self.first = Some(next);
+ }
+ }
+ }
+
+ /// Adds the given object after another object already in the list.
+ ///
+ /// # Safety
+ ///
+ /// Callers must ensure that:
+ /// - The existing object is currently in the list.
+ /// - The new object is not currently in any lists.
+ /// - The new object remains alive until it is removed from the list.
+ /// - The new object is not moved until it is removed from the list.
+ pub unsafe fn insert_after(&mut self, existing: NonNull<A::EntryType>, new: &A::EntryType) {
+ // SAFETY: We have mutable access to the list, so we also have access to the entry we're
+ // about to insert (and it's not in any other lists per the function safety requirements).
+ let new_inner = unsafe { &mut *A::to_links(new).0.get() };
+
+ // SAFETY: Per the function safety requirements, `existing` is in the list.
+ let existing_inner = unsafe { self.inner(existing) };
+ let next = existing_inner.next;
+
+ // INVARIANTS: All fields of the links of the newly-inserted object are initialised below.
+ new_inner.write(LinksInner {
+ next,
+ prev: existing,
+ _pin: PhantomPinned,
+ });
+
+ existing_inner.next = NonNull::from(new);
+
+ // SAFETY: `next` is in the list because it's pointed at by the existing entry.
+ unsafe { self.inner(next).prev = NonNull::from(new) };
+ }
+
+ /// Adds the given object before another object already in the list.
+ ///
+ /// # Safety
+ ///
+ /// Callers must ensure that:
+ /// - The existing object is currently in the list.
+ /// - The new object is not currently in any lists.
+ /// - The new object remains alive until it is removed from the list.
+ /// - The new object is not moved until it is removed from the list.
+ pub unsafe fn insert_before(&mut self, existing: NonNull<A::EntryType>, new: &A::EntryType) {
+ // SAFETY: The safety requirements of this function satisfy those of `insert_after`.
+ unsafe { self.insert_after(self.inner_ref(existing).prev, new) };
+
+ if core::ptr::eq(self.first.unwrap().as_ptr(), existing.as_ptr()) {
+ // Update the pointer to the first element as we're inserting before it.
+ self.first = Some(NonNull::from(new));
+ }
+ }
+
+ /// Returns the first element of the list, if one exists.
+ pub fn front(&self) -> Option<NonNull<A::EntryType>> {
+ self.first
+ }
+
+ /// Returns the last element of the list, if one exists.
+ pub fn back(&self) -> Option<NonNull<A::EntryType>> {
+ // SAFETY: Having a pointer to it guarantees that the object is in the list.
+ self.first.map(|f| unsafe { self.inner_ref(f).prev })
+ }
+
+ /// Returns an iterator for the list starting at the first entry.
+ pub fn iter(&self) -> Iterator<'_, A> {
+ Iterator::new(self.cursor_front())
+ }
+
+ /// Returns an iterator for the list starting at the last entry.
+ pub fn iter_back(&self) -> impl iter::DoubleEndedIterator<Item = &'_ A::EntryType> {
+ Iterator::new(self.cursor_back())
+ }
+
+ /// Returns a cursor starting on the first (front) element of the list.
+ pub fn cursor_front(&self) -> Cursor<'_, A> {
+ // SAFETY: `front` is in the list (or is `None`) because we've read it from the list head
+ // and the list cannot have changed because we hold a shared reference to it.
+ unsafe { Cursor::new(self, self.front()) }
+ }
+
+ /// Returns a cursor starting on the last (back) element of the list.
+ pub fn cursor_back(&self) -> Cursor<'_, A> {
+ // SAFETY: `back` is in the list (or is `None`) because we've read it from the list head
+ // and the list cannot have changed because we hold a shared reference to it.
+ unsafe { Cursor::new(self, self.back()) }
+ }
+
+ /// Returns a mutable reference to the links of a given object.
+ ///
+ /// # Safety
+ ///
+ /// Callers must ensure that the element is in the list.
+ unsafe fn inner(&mut self, ptr: NonNull<A::EntryType>) -> &mut LinksInner<A::EntryType> {
+ // SAFETY: The safety requirements guarantee that we the links are initialised because
+ // that's part of the type invariants. Additionally, the type invariants also guarantee
+ // that having a mutable reference to the list guarantees that the links are mutably
+ // accessible as well.
+ unsafe { (*A::to_links(ptr.as_ref()).0.get()).assume_init_mut() }
+ }
+
+ /// Returns a shared reference to the links of a given object.
+ ///
+ /// # Safety
+ ///
+ /// Callers must ensure that the element is in the list.
+ unsafe fn inner_ref(&self, ptr: NonNull<A::EntryType>) -> &LinksInner<A::EntryType> {
+ // SAFETY: The safety requirements guarantee that we the links are initialised because
+ // that's part of the type invariants. Additionally, the type invariants also guarantee
+ // that having a shared reference to the list guarantees that the links are accessible in
+ // shared mode as well.
+ unsafe { (*A::to_links(ptr.as_ref()).0.get()).assume_init_ref() }
+ }
+}
+
+impl<'a, A: Adapter + ?Sized> iter::IntoIterator for &'a List<A> {
+ type Item = &'a A::EntryType;
+ type IntoIter = Iterator<'a, A>;
+ fn into_iter(self) -> Self::IntoIter {
+ self.iter()
+ }
+}
+
+/// An iterator for the linked list.
+pub struct Iterator<'a, A: Adapter + ?Sized> {
+ cursor: Cursor<'a, A>,
+}
+
+impl<'a, A: Adapter + ?Sized> Iterator<'a, A> {
+ fn new(cursor: Cursor<'a, A>) -> Self {
+ Self { cursor }
+ }
+}
+
+impl<'a, A: Adapter + ?Sized> iter::Iterator for Iterator<'a, A> {
+ type Item = &'a A::EntryType;
+
+ fn next(&mut self) -> Option<Self::Item> {
+ let ret = self.cursor.current()?;
+ self.cursor.move_next();
+ Some(ret)
+ }
+}
+
+impl<A: Adapter + ?Sized> iter::DoubleEndedIterator for Iterator<'_, A> {
+ fn next_back(&mut self) -> Option<Self::Item> {
+ let ret = self.cursor.current()?;
+ self.cursor.move_prev();
+ Some(ret)
+ }
+}
+
+/// A linked-list adapter.
+///
+/// It is a separate type (as opposed to implemented by the type of the elements of the list)
+/// so that a given type can be inserted into multiple lists at the same time; in such cases, each
+/// list needs its own adapter that returns a different pointer to links.
+///
+/// It may, however, be implemented by the type itself to be inserted into lists, which makes it
+/// more readable.
+///
+/// # Safety
+///
+/// Implementers must ensure that the links returned by [`Adapter::to_links`] are unique to the
+/// adapter. That is, different adapters must return different links for a given object.
+///
+/// The reason for this requirement is to avoid confusion that may lead to UB. In particular, if
+/// two adapters were to use the same links, a user may have two lists (one for each adapter) and
+/// try to insert the same object into both at the same time; although this clearly violates the
+/// list safety requirements (e.g., those in [`List::push_back`]), for users to notice it, they'd
+/// have to dig into the details of the two adapters.
+///
+/// By imposing the requirement on the adapter, we make it easier for users to check compliance
+/// with the requirements when using the list.
+///
+/// # Examples
+///
+/// ```
+/// # use linked_list::unsafe_list::{Adapter, Links, List};
+///
+/// struct Example {
+/// a: u32,
+/// b: u32,
+/// links1: Links<Example>,
+/// links2: Links<Example>,
+/// }
+///
+/// // SAFETY: This adapter is the only one that uses `Example::links1`.
+/// unsafe impl Adapter for Example {
+/// type EntryType = Self;
+/// fn to_links(obj: &Self) -> &Links<Self> {
+/// &obj.links1
+/// }
+/// }
+///
+/// struct ExampleAdapter;
+///
+/// // SAFETY: This adapter is the only one that uses `Example::links2`.
+/// unsafe impl Adapter for ExampleAdapter {
+/// type EntryType = Example;
+/// fn to_links(obj: &Example) -> &Links<Example> {
+/// &obj.links2
+/// }
+/// }
+///
+/// static LIST1: List<Example> = List::new();
+/// static LIST2: List<ExampleAdapter> = List::new();
+/// ```
+pub unsafe trait Adapter {
+ /// The type of the enties in the list.
+ type EntryType: ?Sized;
+
+ /// Retrieves the linked list links for the given object.
+ fn to_links(obj: &Self::EntryType) -> &Links<Self::EntryType>;
+}
+
+struct LinksInner<T: ?Sized> {
+ next: NonNull<T>,
+ prev: NonNull<T>,
+ _pin: PhantomPinned,
+}
+
+/// Links of a linked list.
+///
+/// List entries need one of these per concurrent list.
+pub struct Links<T: ?Sized>(UnsafeCell<MaybeUninit<LinksInner<T>>>);
+
+// SAFETY: `Links` can be safely sent to other threads but we restrict it to being `Send` only when
+// the list entries it points to are also `Send`.
+unsafe impl<T: ?Sized> Send for Links<T> {}
+
+// SAFETY: `Links` is usable from other threads via references but we restrict it to being `Sync`
+// only when the list entries it points to are also `Sync`.
+unsafe impl<T: ?Sized> Sync for Links<T> {}
+
+impl<T: ?Sized> Links<T> {
+ /// Constructs a new instance of the linked-list links.
+ pub const fn new() -> Self {
+ Self(UnsafeCell::new(MaybeUninit::uninit()))
+ }
+}
+
+pub(crate) struct CommonCursor<A: Adapter + ?Sized> {
+ pub(crate) cur: Option<NonNull<A::EntryType>>,
+}
+
+impl<A: Adapter + ?Sized> CommonCursor<A> {
+ pub(crate) fn new(cur: Option<NonNull<A::EntryType>>) -> Self {
+ Self { cur }
+ }
+
+ /// Moves the cursor to the next entry of the list.
+ ///
+ /// # Safety
+ ///
+ /// Callers must ensure that the cursor is either [`None`] or points to an entry that is in
+ /// `list`.
+ pub(crate) unsafe fn move_next(&mut self, list: &List<A>) {
+ match self.cur.take() {
+ None => self.cur = list.first,
+ Some(cur) => {
+ if let Some(head) = list.first {
+ // SAFETY: Per the function safety requirements, `cur` is in the list.
+ let links = unsafe { list.inner_ref(cur) };
+ if !core::ptr::eq(links.next.as_ptr(), head.as_ptr()) {
+ self.cur = Some(links.next);
+ }
+ }
+ }
+ }
+ }
+
+ /// Moves the cursor to the previous entry of the list.
+ ///
+ /// # Safety
+ ///
+ /// Callers must ensure that the cursor is either [`None`] or points to an entry that is in
+ /// `list`.
+ pub(crate) unsafe fn move_prev(&mut self, list: &List<A>) {
+ match list.first {
+ None => self.cur = None,
+ Some(head) => {
+ let next = match self.cur.take() {
+ None => head,
+ Some(cur) => {
+ if core::ptr::eq(cur.as_ptr(), head.as_ptr()) {
+ return;
+ }
+ cur
+ }
+ };
+ // SAFETY: `next` is either `head` or `cur`. The former is in the list because it's
+ // its head; the latter is in the list per the function safety requirements.
+ self.cur = Some(unsafe { list.inner_ref(next) }.prev);
+ }
+ }
+ }
+}
+
+/// A list cursor that allows traversing a linked list and inspecting elements.
+pub struct Cursor<'a, A: Adapter + ?Sized> {
+ cursor: CommonCursor<A>,
+ list: &'a List<A>,
+}
+
+impl<'a, A: Adapter + ?Sized> Cursor<'a, A> {
+ /// Creates a new cursor.
+ ///
+ /// # Safety
+ ///
+ /// Callers must ensure that `cur` is either [`None`] or points to an entry in `list`.
+ pub(crate) unsafe fn new(list: &'a List<A>, cur: Option<NonNull<A::EntryType>>) -> Self {
+ Self {
+ list,
+ cursor: CommonCursor::new(cur),
+ }
+ }
+
+ /// Returns the element the cursor is currently positioned on.
+ pub fn current(&self) -> Option<&'a A::EntryType> {
+ let cur = self.cursor.cur?;
+ // SAFETY: `cursor` starts off in the list and only changes within the list. Additionally,
+ // the list cannot change because we hold a shared reference to it, so the cursor is always
+ // within the list.
+ Some(unsafe { cur.as_ref() })
+ }
+
+ /// Moves the cursor to the next element.
+ pub fn move_next(&mut self) {
+ // SAFETY: `cursor` starts off in the list and only changes within the list. Additionally,
+ // the list cannot change because we hold a shared reference to it, so the cursor is always
+ // within the list.
+ unsafe { self.cursor.move_next(self.list) };
+ }
+
+ /// Moves the cursor to the previous element.
+ pub fn move_prev(&mut self) {
+ // SAFETY: `cursor` starts off in the list and only changes within the list. Additionally,
+ // the list cannot change because we hold a shared reference to it, so the cursor is always
+ // within the list.
+ unsafe { self.cursor.move_prev(self.list) };
+ }
+}
+
+#[cfg(test)]
+mod tests {
+ extern crate alloc;
+ use alloc::{boxed::Box, vec::Vec};
+ use core::ptr::NonNull;
+
+ struct Example {
+ links: super::Links<Self>,
+ }
+
+ // SAFETY: This is the only adapter that uses `Example::links`.
+ unsafe impl super::Adapter for Example {
+ type EntryType = Self;
+ fn to_links(obj: &Self) -> &super::Links<Self> {
+ &obj.links
+ }
+ }
+
+ fn build_vector(size: usize) -> Vec<Box<Example>> {
+ let mut v = Vec::new();
+ v.reserve(size);
+ for _ in 0..size {
+ v.push(Box::new(Example {
+ links: super::Links::new(),
+ }));
+ }
+ v
+ }
+
+ #[track_caller]
+ fn assert_list_contents(v: &[Box<Example>], list: &super::List<Example>) {
+ let n = v.len();
+
+ // Assert that the list is ok going forward.
+ let mut count = 0;
+ for (i, e) in list.iter().enumerate() {
+ assert!(core::ptr::eq(e, &*v[i]));
+ count += 1;
+ }
+ assert_eq!(count, n);
+
+ // Assert that the list is ok going backwards.
+ let mut count = 0;
+ for (i, e) in list.iter_back().rev().enumerate() {
+ assert!(core::ptr::eq(e, &*v[n - 1 - i]));
+ count += 1;
+ }
+ assert_eq!(count, n);
+ }
+
+ #[track_caller]
+ fn test_each_element(
+ min_len: usize,
+ max_len: usize,
+ test: impl Fn(&mut Vec<Box<Example>>, &mut super::List<Example>, usize, Box<Example>),
+ ) {
+ for n in min_len..=max_len {
+ for i in 0..n {
+ let extra = Box::new(Example {
+ links: super::Links::new(),
+ });
+ let mut v = build_vector(n);
+ let mut list = super::List::<Example>::new();
+
+ // Build list.
+ for j in 0..n {
+ // SAFETY: The entry was allocated above, it's not in any lists yet, is never
+ // moved, and outlives the list.
+ unsafe { list.push_back(&v[j]) };
+ }
+
+ // Call the test case.
+ test(&mut v, &mut list, i, extra);
+
+ // Check that the list is ok.
+ assert_list_contents(&v, &list);
+ }
+ }
+ }
+
+ #[test]
+ fn test_push_back() {
+ const MAX: usize = 10;
+ let v = build_vector(MAX);
+ let mut list = super::List::<Example>::new();
+
+ for n in 1..=MAX {
+ // SAFETY: The entry was allocated above, it's not in any lists yet, is never moved,
+ // and outlives the list.
+ unsafe { list.push_back(&v[n - 1]) };
+ assert_list_contents(&v[..n], &list);
+ }
+ }
+
+ #[test]
+ fn test_push_front() {
+ const MAX: usize = 10;
+ let v = build_vector(MAX);
+ let mut list = super::List::<Example>::new();
+
+ for n in 1..=MAX {
+ // SAFETY: The entry was allocated above, it's not in any lists yet, is never moved,
+ // and outlives the list.
+ unsafe { list.push_front(&v[MAX - n]) };
+ assert_list_contents(&v[MAX - n..], &list);
+ }
+ }
+
+ #[test]
+ fn test_one_removal() {
+ test_each_element(1, 10, |v, list, i, _| {
+ // Remove the i-th element.
+ // SAFETY: The i-th element was added to the list above, and wasn't removed yet.
+ unsafe { list.remove(&v[i]) };
+ v.remove(i);
+ });
+ }
+
+ #[test]
+ fn test_one_insert_after() {
+ test_each_element(1, 10, |v, list, i, extra| {
+ // Insert after the i-th element.
+ // SAFETY: The i-th element was added to the list above, and wasn't removed yet.
+ // Additionally, the new element isn't in any list yet, isn't moved, and outlives
+ // the list.
+ unsafe { list.insert_after(NonNull::from(&*v[i]), &*extra) };
+ v.insert(i + 1, extra);
+ });
+ }
+
+ #[test]
+ fn test_one_insert_before() {
+ test_each_element(1, 10, |v, list, i, extra| {
+ // Insert before the i-th element.
+ // SAFETY: The i-th element was added to the list above, and wasn't removed yet.
+ // Additionally, the new element isn't in any list yet, isn't moved, and outlives
+ // the list.
+ unsafe { list.insert_before(NonNull::from(&*v[i]), &*extra) };
+ v.insert(i, extra);
+ });
+ }
+}
+fn:) to \
+ restrict the search to a given item kind.","Accepted kinds are: fn, mod, struct, \
+ enum, trait, type, macro, \
+ and const.","Search functions by type signature (e.g., vec -> usize or \
+ -> vec or String, enum:Cow -> bool)","You can look for items with an exact name by putting double quotes around \
+ your request: \"string\"","Look for functions that accept or return \
+ slices and \
+ arrays by writing \
+ square brackets (e.g., -> [u8] or [] -> Option)","Look for items inside another one by searching for a path: vec::Vec",].map(x=>""+x+"
").join("");const div_infos=document.createElement("div");addClass(div_infos,"infos");div_infos.innerHTML="${value.replaceAll(" ", " ")}`}else{error[index]=value}});output+=`