diff options
Diffstat (limited to 'third_party/rust/uluru')
| -rw-r--r-- | third_party/rust/uluru/.cargo-checksum.json | 1 | ||||
| -rw-r--r-- | third_party/rust/uluru/Cargo.toml | 27 | ||||
| -rw-r--r-- | third_party/rust/uluru/LICENSE | 373 | ||||
| -rw-r--r-- | third_party/rust/uluru/README.md | 12 | ||||
| -rw-r--r-- | third_party/rust/uluru/src/lib.rs | 341 | ||||
| -rw-r--r-- | third_party/rust/uluru/src/tests.rs | 216 |
6 files changed, 970 insertions, 0 deletions
diff --git a/third_party/rust/uluru/.cargo-checksum.json b/third_party/rust/uluru/.cargo-checksum.json new file mode 100644 index 0000000000..d2996c097f --- /dev/null +++ b/third_party/rust/uluru/.cargo-checksum.json @@ -0,0 +1 @@ +{"files":{"Cargo.toml":"ccdd1542eacc6997f531dcf6aaba11659a7caed7935956b59121f2ca24168344","LICENSE":"3db78572e8657cca9e9446ce56a057b8a981eb41af318c49a5fe08e7a10fa52a","README.md":"ba37d1f9ea9f852f81d984b612c9028ccc96d9e1da6d9bf2c7fb51cbf10c9066","src/lib.rs":"f8990d5ff57fc701aff48338cb03e8b10e61a5f453951227823fa1ab591565cd","src/tests.rs":"7b748c3be231655c3fda95da219c6f13b4c3f6b9b383457d42b6dea35fdf6b38"},"package":"794a32261a1f5eb6a4462c81b59cec87b5c27d5deea7dd1ac8fc781c41d226db"}
\ No newline at end of file diff --git a/third_party/rust/uluru/Cargo.toml b/third_party/rust/uluru/Cargo.toml new file mode 100644 index 0000000000..9399b085af --- /dev/null +++ b/third_party/rust/uluru/Cargo.toml @@ -0,0 +1,27 @@ +# 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] +edition = "2018" +name = "uluru" +version = "3.0.0" +authors = ["The Servo Project Developers", "Matt Brubeck <mbrubeck@limpet.net>"] +include = ["src/**/*", "LICENSE", "README.md"] +description = "A simple, fast, LRU cache implementation" +readme = "README.md" +keywords = ["cache", "linkedlist", "array", "no_std"] +categories = ["data-structures", "no-std"] +license = "MPL-2.0" +repository = "https://github.com/servo/uluru" +[dependencies.arrayvec] +version = "0.7" +default-features = false diff --git a/third_party/rust/uluru/LICENSE b/third_party/rust/uluru/LICENSE new file mode 100644 index 0000000000..9ad641286f --- /dev/null +++ b/third_party/rust/uluru/LICENSE @@ -0,0 +1,373 @@ + Mozilla Public License Version 2.0 +================================== + +1. Definitions +-------------- + +1.1. "Contributor" +means each individual or legal entity that creates, contributes to +the creation of, or owns Covered Software. + +1.2. "Contributor Version" +means the combination of the Contributions of others (if any) used +by a Contributor and that particular Contributor's Contribution. + +1.3. "Contribution" +means Covered Software of a particular Contributor. + +1.4. "Covered Software" +means Source Code Form to which the initial Contributor has attached +the notice in Exhibit A, the Executable Form of such Source Code +Form, and Modifications of such Source Code Form, in each case +including portions thereof. + +1.5. "Incompatible With Secondary Licenses" +means + +(a) that the initial Contributor has attached the notice described +in Exhibit B to the Covered Software; or + +(b) that the Covered Software was made available under the terms of +version 1.1 or earlier of the License, but not also under the +terms of a Secondary License. + +1.6. "Executable Form" +means any form of the work other than Source Code Form. + +1.7. "Larger Work" +means a work that combines Covered Software with other material, in +a separate file or files, that is not Covered Software. + +1.8. "License" +means this document. + +1.9. "Licensable" +means having the right to grant, to the maximum extent possible, +whether at the time of the initial grant or subsequently, any and +all of the rights conveyed by this License. + +1.10. "Modifications" +means any of the following: + +(a) any file in Source Code Form that results from an addition to, +deletion from, or modification of the contents of Covered +Software; or + +(b) any new file in Source Code Form that contains any Covered +Software. + +1.11. "Patent Claims" of a Contributor +means any patent claim(s), including without limitation, method, +process, and apparatus claims, in any patent Licensable by such +Contributor that would be infringed, but for the grant of the +License, by the making, using, selling, offering for sale, having +made, import, or transfer of either its Contributions or its +Contributor Version. + +1.12. "Secondary License" +means either the GNU General Public License, Version 2.0, the GNU +Lesser General Public License, Version 2.1, the GNU Affero General +Public License, Version 3.0, or any later versions of those +licenses. + +1.13. "Source Code Form" +means the form of the work preferred for making modifications. + +1.14. "You" (or "Your") +means an individual or a legal entity exercising rights under this +License. For legal entities, "You" includes any entity that +controls, is controlled by, or is under common control with You. For +purposes of this definition, "control" means (a) the power, direct +or indirect, to cause the direction or management of such entity, +whether by contract or otherwise, or (b) ownership of more than +fifty percent (50%) of the outstanding shares or beneficial +ownership of such entity. + +2. License Grants and Conditions +-------------------------------- + +2.1. Grants + +Each Contributor hereby grants You a world-wide, royalty-free, +non-exclusive license: + +(a) under intellectual property rights (other than patent or trademark) +Licensable by such Contributor to use, reproduce, make available, +modify, display, perform, distribute, and otherwise exploit its +Contributions, either on an unmodified basis, with Modifications, or +as part of a Larger Work; and + +(b) under Patent Claims of such Contributor to make, use, sell, offer +for sale, have made, import, and otherwise transfer either its +Contributions or its Contributor Version. + +2.2. Effective Date + +The licenses granted in Section 2.1 with respect to any Contribution +become effective for each Contribution on the date the Contributor first +distributes such Contribution. + +2.3. Limitations on Grant Scope + +The licenses granted in this Section 2 are the only rights granted under +this License. No additional rights or licenses will be implied from the +distribution or licensing of Covered Software under this License. +Notwithstanding Section 2.1(b) above, no patent license is granted by a +Contributor: + +(a) for any code that a Contributor has removed from Covered Software; +or + +(b) for infringements caused by: (i) Your and any other third party's +modifications of Covered Software, or (ii) the combination of its +Contributions with other software (except as part of its Contributor +Version); or + +(c) under Patent Claims infringed by Covered Software in the absence of +its Contributions. + +This License does not grant any rights in the trademarks, service marks, +or logos of any Contributor (except as may be necessary to comply with +the notice requirements in Section 3.4). + +2.4. Subsequent Licenses + +No Contributor makes additional grants as a result of Your choice to +distribute the Covered Software under a subsequent version of this +License (see Section 10.2) or under the terms of a Secondary License (if +permitted under the terms of Section 3.3). + +2.5. Representation + +Each Contributor represents that the Contributor believes its +Contributions are its original creation(s) or it has sufficient rights +to grant the rights to its Contributions conveyed by this License. + +2.6. Fair Use + +This License is not intended to limit any rights You have under +applicable copyright doctrines of fair use, fair dealing, or other +equivalents. + +2.7. Conditions + +Sections 3.1, 3.2, 3.3, and 3.4 are conditions of the licenses granted +in Section 2.1. + +3. Responsibilities +------------------- + +3.1. Distribution of Source Form + +All distribution of Covered Software in Source Code Form, including any +Modifications that You create or to which You contribute, must be under +the terms of this License. You must inform recipients that the Source +Code Form of the Covered Software is governed by the terms of this +License, and how they can obtain a copy of this License. You may not +attempt to alter or restrict the recipients' rights in the Source Code +Form. + +3.2. Distribution of Executable Form + +If You distribute Covered Software in Executable Form then: + +(a) such Covered Software must also be made available in Source Code +Form, as described in Section 3.1, and You must inform recipients of +the Executable Form how they can obtain a copy of such Source Code +Form by reasonable means in a timely manner, at a charge no more +than the cost of distribution to the recipient; and + +(b) You may distribute such Executable Form under the terms of this +License, or sublicense it under different terms, provided that the +license for the Executable Form does not attempt to limit or alter +the recipients' rights in the Source Code Form under this License. + +3.3. Distribution of a Larger Work + +You may create and distribute a Larger Work under terms of Your choice, +provided that You also comply with the requirements of this License for +the Covered Software. If the Larger Work is a combination of Covered +Software with a work governed by one or more Secondary Licenses, and the +Covered Software is not Incompatible With Secondary Licenses, this +License permits You to additionally distribute such Covered Software +under the terms of such Secondary License(s), so that the recipient of +the Larger Work may, at their option, further distribute the Covered +Software under the terms of either this License or such Secondary +License(s). + +3.4. Notices + +You may not remove or alter the substance of any license notices +(including copyright notices, patent notices, disclaimers of warranty, +or limitations of liability) contained within the Source Code Form of +the Covered Software, except that You may alter any license notices to +the extent required to remedy known factual inaccuracies. + +3.5. Application of Additional Terms + +You may choose to offer, and to charge a fee for, warranty, support, +indemnity or liability obligations to one or more recipients of Covered +Software. However, You may do so only on Your own behalf, and not on +behalf of any Contributor. You must make it absolutely clear that any +such warranty, support, indemnity, or liability obligation is offered by +You alone, and You hereby agree to indemnify every Contributor for any +liability incurred by such Contributor as a result of warranty, support, +indemnity or liability terms You offer. You may include additional +disclaimers of warranty and limitations of liability specific to any +jurisdiction. + +4. Inability to Comply Due to Statute or Regulation +--------------------------------------------------- + +If it is impossible for You to comply with any of the terms of this +License with respect to some or all of the Covered Software due to +statute, judicial order, or regulation then You must: (a) comply with +the terms of this License to the maximum extent possible; and (b) +describe the limitations and the code they affect. Such description must +be placed in a text file included with all distributions of the Covered +Software under this License. Except to the extent prohibited by statute +or regulation, such description must be sufficiently detailed for a +recipient of ordinary skill to be able to understand it. + +5. Termination +-------------- + +5.1. The rights granted under this License will terminate automatically +if You fail to comply with any of its terms. However, if You become +compliant, then the rights granted under this License from a particular +Contributor are reinstated (a) provisionally, unless and until such +Contributor explicitly and finally terminates Your grants, and (b) on an +ongoing basis, if such Contributor fails to notify You of the +non-compliance by some reasonable means prior to 60 days after You have +come back into compliance. Moreover, Your grants from a particular +Contributor are reinstated on an ongoing basis if such Contributor +notifies You of the non-compliance by some reasonable means, this is the +first time You have received notice of non-compliance with this License +from such Contributor, and You become compliant prior to 30 days after +Your receipt of the notice. + +5.2. If You initiate litigation against any entity by asserting a patent +infringement claim (excluding declaratory judgment actions, +counter-claims, and cross-claims) alleging that a Contributor Version +directly or indirectly infringes any patent, then the rights granted to +You by any and all Contributors for the Covered Software under Section +2.1 of this License shall terminate. + +5.3. In the event of termination under Sections 5.1 or 5.2 above, all +end user license agreements (excluding distributors and resellers) which +have been validly granted by You or Your distributors under this License +prior to termination shall survive termination. + +************************************************************************ +* * +* 6. Disclaimer of Warranty * +* ------------------------- * +* * +* Covered Software is provided under this License on an "as is" * +* basis, without warranty of any kind, either expressed, implied, or * +* statutory, including, without limitation, warranties that the * +* Covered Software is free of defects, merchantable, fit for a * +* particular purpose or non-infringing. The entire risk as to the * +* quality and performance of the Covered Software is with You. * +* Should any Covered Software prove defective in any respect, You * +* (not any Contributor) assume the cost of any necessary servicing, * +* repair, or correction. This disclaimer of warranty constitutes an * +* essential part of this License. No use of any Covered Software is * +* authorized under this License except under this disclaimer. * +* * +************************************************************************ + +************************************************************************ +* * +* 7. Limitation of Liability * +* -------------------------- * +* * +* Under no circumstances and under no legal theory, whether tort * +* (including negligence), contract, or otherwise, shall any * +* Contributor, or anyone who distributes Covered Software as * +* permitted above, be liable to You for any direct, indirect, * +* special, incidental, or consequential damages of any character * +* including, without limitation, damages for lost profits, loss of * +* goodwill, work stoppage, computer failure or malfunction, or any * +* and all other commercial damages or losses, even if such party * +* shall have been informed of the possibility of such damages. This * +* limitation of liability shall not apply to liability for death or * +* personal injury resulting from such party's negligence to the * +* extent applicable law prohibits such limitation. Some * +* jurisdictions do not allow the exclusion or limitation of * +* incidental or consequential damages, so this exclusion and * +* limitation may not apply to You. * +* * +************************************************************************ + +8. Litigation +------------- + +Any litigation relating to this License may be brought only in the +courts of a jurisdiction where the defendant maintains its principal +place of business and such litigation shall be governed by laws of that +jurisdiction, without reference to its conflict-of-law provisions. +Nothing in this Section shall prevent a party's ability to bring +cross-claims or counter-claims. + +9. Miscellaneous +---------------- + +This License represents the complete agreement concerning the subject +matter hereof. If any provision of this License is held to be +unenforceable, such provision shall be reformed only to the extent +necessary to make it enforceable. Any law or regulation which provides +that the language of a contract shall be construed against the drafter +shall not be used to construe this License against a Contributor. + +10. Versions of the License +--------------------------- + +10.1. New Versions + +Mozilla Foundation is the license steward. Except as provided in Section +10.3, no one other than the license steward has the right to modify or +publish new versions of this License. Each version will be given a +distinguishing version number. + +10.2. Effect of New Versions + +You may distribute the Covered Software under the terms of the version +of the License under which You originally received the Covered Software, +or under the terms of any subsequent version published by the license +steward. + +10.3. Modified Versions + +If you create software not governed by this License, and you want to +create a new license for such software, you may create and use a +modified version of this License if you rename the license and remove +any references to the name of the license steward (except to note that +such modified license differs from this License). + +10.4. Distributing Source Code Form that is Incompatible With Secondary +Licenses + +If You choose to distribute Source Code Form that is Incompatible With +Secondary Licenses under the terms of this version of the License, the +notice described in Exhibit B of this License must be attached. + +Exhibit A - Source Code Form License Notice +------------------------------------------- + +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/. + +If it is not possible or desirable to put the notice in a particular +file, then You may include the notice in a location (such as a LICENSE +file in a relevant directory) where a recipient would be likely to look +for such a notice. + +You may add additional accurate notices of copyright ownership. + +Exhibit B - "Incompatible With Secondary Licenses" Notice +--------------------------------------------------------- + +This Source Code Form is "Incompatible With Secondary Licenses", as +defined by the Mozilla Public License, v. 2.0. diff --git a/third_party/rust/uluru/README.md b/third_party/rust/uluru/README.md new file mode 100644 index 0000000000..82244786e5 --- /dev/null +++ b/third_party/rust/uluru/README.md @@ -0,0 +1,12 @@ +# uluru + +A simple, fast, least-recently-used (LRU) cache implementation used for +Servo's style system. + +`LRUCache` uses a fixed-capacity array for storage. It provides `O(1)` +insertion, and `O(n)` lookup. It does not require an allocator and can be +used in `no_std` crates. It is implemented in 100% safe Rust. + +* [Documentation](https://docs.rs/uluru) +* [crates.io](https://crates.io/crates/uluru) +* [Release notes](https://github.com/servo/uluru/releases) diff --git a/third_party/rust/uluru/src/lib.rs b/third_party/rust/uluru/src/lib.rs new file mode 100644 index 0000000000..0c410509c1 --- /dev/null +++ b/third_party/rust/uluru/src/lib.rs @@ -0,0 +1,341 @@ +/* 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/. */ + +#![no_std] +#![deny(unsafe_code)] + +//! A simple, fast, least-recently-used (LRU) cache. +//! +//! [`LRUCache`] uses a fixed-capacity array for storage. It provides `O(1)` insertion, and `O(n)` +//! lookup. It does not require an allocator and can be used in `no_std` crates. +//! +//! See the [`LRUCache`](LRUCache) docs for details. + +use arrayvec::ArrayVec; +use core::{fmt, mem::replace}; + +#[cfg(test)] +mod tests; + +/// A LRU cache using a statically-sized array for storage. +/// +/// `LRUCache` uses a fixed-capacity array for storage. It provides `O(1)` insertion, and `O(n)` +/// lookup. +/// +/// All items are stored inline within the `LRUCache`, so it does not impose any heap allocation or +/// indirection. A linked list is used to record the cache order, so the items themselves do not +/// need to be moved when the order changes. (This is important for speed if the items are large.) +/// +/// # Example +/// +/// ``` +/// use uluru::LRUCache; +/// +/// struct MyValue { +/// id: u32, +/// name: &'static str, +/// } +/// +/// // A cache with a capacity of three. +/// type MyCache = LRUCache<MyValue, 3>; +/// +/// // Create an empty cache, then insert some items. +/// let mut cache = MyCache::default(); +/// cache.insert(MyValue { id: 1, name: "Mercury" }); +/// cache.insert(MyValue { id: 2, name: "Venus" }); +/// cache.insert(MyValue { id: 3, name: "Earth" }); +/// +/// // Use the `find` method to retrieve an item from the cache. +/// // This also "touches" the item, marking it most-recently-used. +/// let item = cache.find(|x| x.id == 1); +/// assert_eq!(item.unwrap().name, "Mercury"); +/// +/// // If the cache is full, inserting a new item evicts the least-recently-used item: +/// cache.insert(MyValue { id: 4, name: "Mars" }); +/// assert!(cache.find(|x| x.id == 2).is_none()); +/// ``` +pub struct LRUCache<T, const N: usize> { + /// The most-recently-used entry is at index `head`. The entries form a linked list, linked to + /// each other by indices within the `entries` array. After an entry is added to the array, + /// its index never changes, so these links are never invalidated. + entries: ArrayVec<Entry<T>, N>, + /// Index of the first entry. If the cache is empty, ignore this field. + head: u16, + /// Index of the last entry. If the cache is empty, ignore this field. + tail: u16, +} + +/// An entry in an `LRUCache`. +#[derive(Debug, Clone)] +struct Entry<T> { + val: T, + /// Index of the previous entry. If this entry is the head, ignore this field. + prev: u16, + /// Index of the next entry. If this entry is the tail, ignore this field. + next: u16, +} + +impl<T, const N: usize> Default for LRUCache<T, N> { + fn default() -> Self { + let cache = LRUCache { + entries: ArrayVec::new(), + head: 0, + tail: 0, + }; + assert!( + cache.entries.capacity() < u16::max_value() as usize, + "Capacity overflow" + ); + cache + } +} + +impl<T, const N: usize> LRUCache<T, N> { + /// Insert a given key in the cache. + /// + /// This item becomes the front (most-recently-used) item in the cache. If the cache is full, + /// the back (least-recently-used) item will be removed and returned. + pub fn insert(&mut self, val: T) -> Option<T> { + let entry = Entry { + val, + prev: 0, + next: 0, + }; + + // If the cache is full, replace the oldest entry. Otherwise, add an entry. + let (new_head, previous_entry) = if self.entries.len() == self.entries.capacity() { + let i = self.pop_back(); + let previous_entry = replace(&mut self.entries[i as usize], entry); + (i, Some(previous_entry.val)) + } else { + self.entries.push(entry); + (self.entries.len() as u16 - 1, None) + }; + + self.push_front(new_head); + previous_entry + } + + /// Returns the first item in the cache that matches the given predicate. + /// Touches the result (makes it most-recently-used) on a hit. + pub fn find<F>(&mut self, pred: F) -> Option<&mut T> + where + F: FnMut(&T) -> bool, + { + if self.touch(pred) { + self.front_mut() + } else { + None + } + } + + /// Performs a lookup on the cache with the given test routine. Touches + /// the result on a hit. + pub fn lookup<F, R>(&mut self, mut test_one: F) -> Option<R> + where + F: FnMut(&mut T) -> Option<R>, + { + let mut result = None; + let mut iter = self.iter_mut(); + while let Some((i, val)) = iter.next() { + if let Some(r) = test_one(val) { + result = Some((i, r)); + break; + } + } + + match result { + None => None, + Some((i, r)) => { + self.touch_index(i); + Some(r) + } + } + } + + /// Returns the number of elements in the cache. + #[inline] + pub fn len(&self) -> usize { + self.entries.len() + } + + /// Returns true if the cache is empty. + #[inline] + pub fn is_empty(&self) -> bool { + self.entries.is_empty() + } + + /// Evict all elements from the cache. + #[inline] + pub fn clear(&mut self) { + self.entries.clear(); + } + + /// Returns the front entry in the list (most recently used). + pub fn front(&self) -> Option<&T> { + self.entries.get(self.head as usize).map(|e| &e.val) + } + + /// Returns a mutable reference to the front entry in the list (most recently used). + pub fn front_mut(&mut self) -> Option<&mut T> { + self.entries.get_mut(self.head as usize).map(|e| &mut e.val) + } + + /// Returns the n-th entry in the list (most recently used). + pub fn get(&self, index: usize) -> Option<&T> { + self.iter().nth(index) + } + + /// Touches the first item in the cache that matches the given predicate (marks it as + /// most-recently-used). + /// Returns `true` on a hit, `false` if no matches. + pub fn touch<F>(&mut self, mut pred: F) -> bool + where + F: FnMut(&T) -> bool, + { + let mut iter = self.iter_mut(); + while let Some((i, val)) = iter.next() { + if pred(val) { + self.touch_index(i); + return true; + } + } + false + } + + /// Iterate over the contents of this cache in order from most-recently-used to + /// least-recently-used. + pub fn iter(&self) -> Iter<'_, T, N> { + Iter { + pos: self.head, + cache: self, + } + } + + /// Iterate mutably over the contents of this cache in order from most-recently-used to + /// least-recently-used. + fn iter_mut(&mut self) -> IterMut<'_, T, N> { + IterMut { + pos: self.head, + cache: self, + } + } + + /// Touch a given entry, putting it first in the list. + #[inline] + fn touch_index(&mut self, idx: u16) { + if idx != self.head { + self.remove(idx); + self.push_front(idx); + } + } + + /// Remove an entry from the linked list. + /// + /// Note: This only unlinks the entry from the list; it does not remove it from the array. + fn remove(&mut self, i: u16) { + let prev = self.entries[i as usize].prev; + let next = self.entries[i as usize].next; + + if i == self.head { + self.head = next; + } else { + self.entries[prev as usize].next = next; + } + + if i == self.tail { + self.tail = prev; + } else { + self.entries[next as usize].prev = prev; + } + } + + /// Insert a new entry at the head of the list. + fn push_front(&mut self, i: u16) { + if self.entries.len() == 1 { + self.tail = i; + } else { + self.entries[i as usize].next = self.head; + self.entries[self.head as usize].prev = i; + } + self.head = i; + } + + /// Remove the last entry from the linked list. Returns the index of the removed entry. + /// + /// Note: This only unlinks the entry from the list; it does not remove it from the array. + fn pop_back(&mut self) -> u16 { + let old_tail = self.tail; + let new_tail = self.entries[old_tail as usize].prev; + self.tail = new_tail; + old_tail + } +} + +impl<T, const N: usize> Clone for LRUCache<T, N> +where + T: Clone, +{ + fn clone(&self) -> Self { + Self { + entries: self.entries.clone(), + head: self.head, + tail: self.tail, + } + } +} + +impl<T, const N: usize> fmt::Debug for LRUCache<T, N> +where + T: fmt::Debug, +{ + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_struct("LRUCache") + .field("head", &self.head) + .field("tail", &self.tail) + .field("entries", &self.entries) + .finish() + } +} + +/// Mutable iterator over values in an `LRUCache`, from most-recently-used to least-recently-used. +struct IterMut<'a, T, const N: usize> { + cache: &'a mut LRUCache<T, N>, + pos: u16, +} + +impl<'a, T, const N: usize> IterMut<'a, T, N> { + fn next(&mut self) -> Option<(u16, &mut T)> { + let index = self.pos; + let entry = self.cache.entries.get_mut(index as usize)?; + + self.pos = if index == self.cache.tail { + N as u16 // Point past the end of the array to signal we are done. + } else { + entry.next + }; + Some((index, &mut entry.val)) + } +} + +/// Iterator over values in an [`LRUCache`], from most-recently-used to least-recently-used. +pub struct Iter<'a, T, const N: usize> { + cache: &'a LRUCache<T, N>, + pos: u16, +} + +impl<'a, T, const N: usize> Iterator for Iter<'a, T, N> { + type Item = &'a T; + + fn next(&mut self) -> Option<&'a T> { + let entry = self.cache.entries.get(self.pos as usize)?; + + self.pos = if self.pos == self.cache.tail { + N as u16 // Point past the end of the array to signal we are done. + } else { + entry.next + }; + Some(&entry.val) + } +} diff --git a/third_party/rust/uluru/src/tests.rs b/third_party/rust/uluru/src/tests.rs new file mode 100644 index 0000000000..978e129449 --- /dev/null +++ b/third_party/rust/uluru/src/tests.rs @@ -0,0 +1,216 @@ +extern crate std; + +use self::std::vec::Vec; +use super::*; + +type TestCache = LRUCache<i32, 4>; + +/// Convenience function for test assertions +fn items<T, const N: usize>(cache: &mut LRUCache<T, N>) -> Vec<T> +where + T: Clone, +{ + let mut v = Vec::new(); + let mut iter = cache.iter_mut(); + while let Some((_idx, val)) = iter.next() { + v.push(val.clone()) + } + v +} + +#[test] +fn empty() { + let mut cache = TestCache::default(); + assert_eq!(cache.is_empty(), true); + assert_eq!(items(&mut cache), []); + cache.insert(1); + assert_eq!(cache.is_empty(), false); +} + +#[test] +fn len() { + let mut cache = TestCache::default(); + cache.insert(1); + assert_eq!(cache.len(), 1); + assert_eq!(items(&mut cache), [1]); +} + +#[test] +fn insert() { + let mut cache = TestCache::default(); + cache.insert(1); + assert_eq!(cache.len(), 1); + cache.insert(2); + assert_eq!(cache.len(), 2); + cache.insert(3); + assert_eq!(cache.len(), 3); + cache.insert(4); + assert_eq!(cache.len(), 4); + assert_eq!( + items(&mut cache), + [4, 3, 2, 1], + "Ordered from most- to least-recent." + ); + + cache.insert(5); + assert_eq!(cache.len(), 4); + assert_eq!( + items(&mut cache), + [5, 4, 3, 2], + "Least-recently-used item evicted." + ); + + cache.insert(6); + cache.insert(7); + cache.insert(8); + cache.insert(9); + assert_eq!( + items(&mut cache), + [9, 8, 7, 6], + "Least-recently-used item evicted." + ); +} + +#[test] +fn lookup() { + let mut cache = TestCache::default(); + cache.insert(1); + cache.insert(2); + cache.insert(3); + cache.insert(4); + + let result = cache.lookup(|x| if *x == 5 { Some(()) } else { None }); + assert_eq!(result, None, "Cache miss."); + assert_eq!(items(&mut cache), [4, 3, 2, 1], "Order not changed."); + + // Cache hit + let result = cache.lookup(|x| if *x == 3 { Some(*x * 2) } else { None }); + assert_eq!(result, Some(6), "Cache hit."); + assert_eq!( + items(&mut cache), + [3, 4, 2, 1], + "Matching item moved to front." + ); +} + +#[test] +fn clear() { + let mut cache = TestCache::default(); + cache.insert(1); + cache.clear(); + assert_eq!(items(&mut cache), [], "all items evicted"); + + cache.insert(1); + cache.insert(2); + cache.insert(3); + cache.insert(4); + assert_eq!(items(&mut cache), [4, 3, 2, 1]); + cache.clear(); + assert_eq!(items(&mut cache), [], "all items evicted again"); +} + +#[test] +fn touch() { + let mut cache = TestCache::default(); + + cache.insert(0); + cache.insert(1); + cache.insert(2); + cache.insert(3); + + cache.touch(|x| *x == 5); + + assert_eq!(items(&mut cache), [3, 2, 1, 0], "Nothing is touched."); + + cache.touch(|x| *x == 1); + + assert_eq!( + items(&mut cache), + [1, 3, 2, 0], + "Touched item is moved to front." + ); +} + +#[test] +fn find() { + let mut cache = TestCache::default(); + + cache.insert(0); + cache.insert(1); + cache.insert(2); + cache.insert(3); + + let result = cache.find(|x| *x == 5).copied(); + + assert_eq!(result, None); + assert_eq!(items(&mut cache), [3, 2, 1, 0], "Nothing is touched."); + + let result = cache.find(|x| *x == 1).copied(); + + assert_eq!(result, Some(1)); + assert_eq!( + items(&mut cache), + [1, 3, 2, 0], + "Retrieved item is moved to front." + ); +} + +#[test] +fn front() { + let mut cache = TestCache::default(); + + assert_eq!(cache.front(), None, "Nothing is in the front."); + + cache.insert(0); + cache.insert(1); + + assert_eq!( + cache.front(), + Some(&1), + "The last inserted item should be in the front." + ); + + cache.touch(|x| *x == 0); + + assert_eq!( + cache.front(), + Some(&0), + "Touched item should be in the front." + ); +} + +#[test] +fn get() { + let mut cache = TestCache::default(); + + assert_eq!(cache.get(0), None, "Nothing at index 0."); + + cache.insert(42); + cache.insert(64); + + assert_eq!( + cache.get(0), + Some(&64), + "The last inserted item should be at index 0." + ); + + assert_eq!( + cache.get(1), + Some(&42), + "The first inserted item should be at index 1." + ); + + cache.touch(|x| *x == 42); + + assert_eq!( + cache.get(0), + Some(&42), + "The last touched item should be at index 0." + ); + + assert_eq!( + cache.get(1), + Some(&64), + "The previously front item should be at index 1." + ); +} |