NightOwl888 opened a new pull request, #826: URL: https://github.com/apache/lucenenet/pull/826
This adds a new ref struct to the project, `Lucene.Net.Util.ValuePriorityQueue<T>`. This struct contains the most of the same API and business logic as `PriorityQueue<T>`, but allows the memory used to be allocated elsewhere as `Span<T>` and passed in. The amount to allocate can be calculated by calling `PriorityQueue.GetArrayHeapSize(maxSize)`, where `maxSize` is the external size of the `PriorityQueue` (representing the same value that is passed into the constructor of the current `PriorityQueue<T>`). The actual allocation amount is 1 greater than the priority queue size because it is 1-based rather than 0-based. We get around the issue with structs not being inheritable by introducing a new `IPriorityComparer<T>` interface with a single `bool LessThan(T a, T b)` method. This signature makes converting existing subclasses of `PriorityQueue<T>` to `IPriorityComparer<T>` straightforward, as there are no business logic changes to make. This comparer is a required constructor argument of `ValuePriorityQueue<T>`. This also modifies `SingleTaxonomyFacets`, `Int32TaxonomyFacets`, `TopDocs` merge and `FST` pack to use `ValuePriorityQueue<T>` and converts the item types they deal with from class to struct so they can be stack allocated if the size is below `Constants.MaxStackByteLimit`, which is set using the [system property](https://github.com/apache/lucenenet/issues/307) `maxStackByteLimit`. Closes #774. Thanks @eladmarg for the suggestion. There are a few more places in the codebase where this type can be useful, but unfortunately the types they use don't convert easily into structs so although we can eliminate the heap allocation of the priority queue itself, we will need some configuration and/or logic to decide whether to allocate the array directly or use an array pool. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: dev-unsubscr...@lucenenet.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org
